HARVARD UNIVERSITY LIBRARY OF THE Museum of Comparative Zoology THE HYLID FROGS OF MIDDLE AMERICA THE HYLID FROGS OF MIDDLE AMERICA Volume 1 WILLIAM E. DUELLMAN Curator Division of Herpetology Museum of Natural History The University of Kansas MONOGRAPH OF THE MUSEUM OF NATURAL HISTORY, THE UNIVERSITY OF KANSAS NUMBER 1 1970 1/ . X MUs- COMP. ZOCL LiRr?Ar?Y HARVARD UNIVERSITY i c. 7^- 3 u<»li - - MONOGRAPH OF THE MUSEUM OF NATURAL HISTORY, THE UNIVERSITY OF KANSAS Number 1, pages 1-753, text figures 1-324, plates 1-72 ( bound in two volumes ) Issued December 15, 1970 PREFACE Nearly two decades have passed since an undergraduate, who was primarily preoccu- pied with snakes at the time, attempted to identify some Mexican tree frogs and sought the aid of Professor Charles F. Walker. The latter offered assistance and encouragement, so that in time the student's field and labora- tory studies turned more and more towards the anurans with special emphasis on the hy- lids. This fortuitous occurrence seemed triv- ial at the time, for the student in 1950, al- though his classroom daydreaming carried him far afield, could not begin to visualize the exciting experiences of the future. A year later the student found himself in Mex- ico trodding paths through the mountains and discovering things new to him around every turn. The die was cast — an inescapable lure of the tropics, a lust that has intensified over the years. Little did he realize that in the ensuing 15 years he would spend more than one thou- sand nights in the quest for the nocturnal songsters, whose calls he came to know as well as the physical features of the frogs them- selves. Nor was it within his powers to fore- see all of the wondrous aspects of nature in the tropics that would pass before his eyes. There are few of the precious memories that can be transcribed adequately to paper, for it is difficult to describe in words such experiences as the grandeur of the forest at Laguna, the moonlight across Golfo Dulce, the awakening in a hammock to the gentle lapping of the waves on the beach of the Peninsula Valiente, the silence of the conif- erous forest on Cerro Barolosa, the quetzals at Cerro Monte Cristo, the curious spider monkeys on Cerro Quia, the distant rumbling of erupting Volcan Irazu at night at La Palma, nor of the joy of having a peccary grace the meager food supplies, or of the aroma of a stewing tinamou, or of the smell of the rain in Chiriqui, the sunrise in the cold and damp- ness on Cerro de la Muerte, nor least of all the splendor of the sunset after the storm at Li- beria. The quest for tree frogs carried him to many strange places and provided him with many challenges, not the least of which was travelling to the back country in search of specimens; travelling in much of Latin Amer- ica cannot be appreciated by the uninitiated, who has not experienced the long hot trip on the flatcar from Arriaga to Tapachula, or the mudslide on the road to Puerto Escondido that temporarily stopped us and once we were through it took the truck that was following us over the mountain, or of careening down a mountain road in a second class Mexican bus whose brakes have just failed and the driver placing his passengers in the "hands of God." Nor is it possible for all persons to appreciate the long hours, nigh days, sitting in an un- comfortable saddle astride a mule plodding steadily across the mountains, as the wind blows your pancho and the rain runs down your neck, nor the three arduous days of pull- ing and pushing a piragua up the Rio Tuira and how a month later we returned down- stream through those same rapids in seven hours, nor of crossing Chiriqui Lagoon in a dugout in the fog and rain and how we ran aground twice on coral reefs, nor of flying to remote airstrips in overloaded Piper Cubs, whose pilots somehow always manage to miss the trees in the passes and find the small clear- ings casually referred to as airstrips. But even in this day of a variety of means of transpor- tation the only way to many of the most inter- esting areas in Middle America is by foot, a time-honored method of travel, though at times painfully slow and arduous, neverthe- less usually trustworthy. The days thus spent seem innumerable, perhaps only because of their apparent length, and are remembered for the steep ascent to Cerro Mali and how heavy our packs were when we reached the top, the scenic walk up the Rio Tacarcuna until the river rose in flood and we made our last ford in water to our chests, the slippery roots that were used for foot-holds on Cerro Pando, and how after all day of slipping and sliding in the rain we reached our campsite on the Rio Changena after dark and how two of our native packers came in later without their packs and we had to return for an hour's walk to fetch our sleeping gear. He has been happy with his associations with many natives, who have provided a sepa- rate, but enduring kind of education. How impressive were the chicleros knowledge of the Peten forest and its inhabitants, or the Negros' ability at guiding the piraguas through the rapids in Darien, or the seem- ingly tirelessness of the packers on Cerro Mali. Memories of these people and others recall many incidents, many humorous, some happy, and a few sad, such as the sobering effect of the escape of a six-foot snake on the patrons of a small Mexican cantina, the sing- ing of our mozos as we rode horseback across the Sierra de Coalcoman, the gleefulness with which Mayan children brought us specimens at Piste, and the caution that our camp boys displayed when catching some animal that they thought to be venomous but moreso the board grins of satisfaction when they learned that they had found something valuable to us. The pleasant memories have been em- bellished with some misfortune, such as the revolution in Guatemala City with the smell of tear gas permeating the cool mountain air, the drunken Tarascans invading our camp and causing several frightful minutes of anxiety, the shooting and fires at the time of the Canal Zone crisis in 1964, but these are solely the everyday events of modern man. Not all of the field work was easy; hard- ships are to be expected, and he would be re- miss if he did not mention the mosquitos at Toocog that made our faces masses of lumps, or of the heat in the Tepalcatepec Valley, or of the cold on Volcan Barba and how the wind blew the rain level across the marsh there, or of losing our way in the swamp near Cosaleacaque and twisting and turning in mud and water for three hours before we came out, or of seeing a companion fall more than 30 feet from a tree, or having the logs break beneath his weight and lose his light and fall into a pool beneath a waterfall with darkness all around, or of having our clothing and sleeping bags partially eaten by ants. But all of these things are only indirectly related to tree frogs. The search for tree frogs brought the stu- dent more than 10,000 specimens from Middle America of all but a few of the known species of hylids, plus many other kinds of amphib- ians and reptiles. The rewards of the field work were gratifying, for the thrill of finding a rare or unknown species in its natural habi- tat is worth many hardships. But the search was not always successful, for how many times did he seek the rare Plectrohyla avia and then upon seeing his only individual, slip and fall in the stream and subsequently dis- cover that the frog had moved away, not to be seen again, or of the four nights spent in the cloud forest on Cerro Uyuca and finding but two frogs, or of finally finding Smilisca phaeota calling in eastern Nicaragua, only to have the tape recorder cease to function, or of hearing unknown calls from the treetops and not being able to find the frogs, or of finding unknown tadpoles and having them die before reaching metamorphosis. These frustrations have been partially compensated by the collection of the second fringe-limbed Hijla in Mexico, the discovery of the wierd spiny frog on Cerro Pando, the identification of the "treetop bopper" with the large Gastro- theca ceratophrys, and of ascending Cerro Monte Cristo for the purpose of obtaining recordings of Hijla sahadorensis and finding them calling in the last stream. Perhaps the present generation of students in biology will not be so fortunate as to trod jungle pathways and see the living results of eons of natural selection, for in the minds of many scientists such mundane approaches to biological problems are history. But the student who was inspired to study tree frogs in 1950 is not displeased with himself for not having donned a white laboratory coat and synthesized proteins or attempted to crack the genetic code and scanned the output of a computer instead of the results of nature. In fact, he hopes to continue his pursuit of the tree frogs into South America where the fauna is even richer and more varied than in Middle America, but before he departs, he wishes to dedicate the present publication to an inspir- ing teacher, valued colleague, and good friend, Charles F. Walker. William E. Duellman Santa Cecilia del Rio Aguarico, Ecuador June 21, 1968 VI CONTENTS Introduction Acknowledgments 3 Materials and Methods 5 Historical Resume 8 Classification and Identification 18 Classification of the Hylidae 18 Taxonomic Characters and Criteria in Hylid Frogs 21 External Morphology _ 21 Coloration ... __ _ 29 Tadpoles 33 Cranial Osteology 43 Chromosomes - 50 Voice 53 Taxonomic Criteria in Hylid Frogs 66 Identification of Middle American Hylid Frogs 69 Key to the Genera of Middle American Hylid Frogs — 69 Key to the Species of Agalychnis 70 Key to the Middle American Species of Gastrotheca 71 Key to the Species and Subspecies of Hyla in Mexico (Northwest of the Isthmus of Tehuantepec) 71 Key to the Species and Subspecies of Hyla in Northern Central America ( Isthmus of Tehuantepec-Honduras, including Yucatan Peninsula) _ 74 Key to the Species and Subspecies of Hyla in Lower Central America ( Nicaragua-Panama) _ ._._ 75 Key to the Middle American Species of Phyllomedusa - 78 Key to the Species of Plectrohyla ... 78 Key to the Species of Pternohyla 78 Key to the Species and Subspecies of Ptychohyla 78 Key to the Species of Smilisca 79 Key to the Species and Subspecies of Triprion 79 Accounts of the Genera and Species 81 Genus Pachymedusa Duellman _ 81 Pachymedusa dacnicolor ( Cope ) 81 Genus Agalychnis Cope ._ 87 Agalychnis saltator Taylor 99 Agalychnis callidryas ( Cope ) 102 Agalychnis moreletii ( Dumeril) 112 Agalychnis annae ( Duellman) _ 117 Agalychnis calcarifer Boulenger 120 Agalychnis spurrelli Boulenger 124 Agalychnis litodryas (Duellman and Trueb) ._ 128 Genus Phyllomedusa Wagler 130 Phyllomedusa lemur Boulenger 132 Phyllomedusa venusta Duellman and Trueb 135 Genus Hemiphractus Wagler 138 Hemiphractus panamensis (Stejneger) 140 Genus Anotheca Smith 144 Anotheca spinosa ( Steindachner) 145 Genus Gastrotheca Fitzinger 151 vii Gastrotheca ceratophrys ( Stejneger ) 153 Gastrotheca nicefori 158 Genus Plirynohyas Fitzinger 160 Phrynohyas venulosa ( Laurenti) ._ .._ 163 Genus Hyla Laurenti 173 The Hyla rubra Group .._ _ 176 Hyla rubra Laurenti 183 Hyla elaeochroa Cope 188 Hyla staufferi Cope 193 Hyla staufferi staufferi Cope 195 Hyla staufferi altae Dunn ____ 199 Hyla boulengeri ( Cope ) 200 Hyla rostrata Peters 204 The Hyla microcephala Group 207 Hyla microcephala Cope 210 Hyla microcephala microcephala Cope 211 Hyla microcephala underwoodi Boulenger 215 Hyla robertmertensi Taylor 217 Hyla phlebodes Stejneger 220 Hyla sartori Smith _ 223 The Hyla leucophyllata Group 226 Hyla ebraccata Cope 227 The Hyla parviceps Group — __ 234 Hyla subocularis Dunn _ 235 The Hyla albomarginata Group 239 Hyla rufitela Fouquette 240 The Hyla boans Group _ 245 Hyla crepitans Wied 247 Hyla rosenbergi Boulenger 253 Hyla boans ( Linnaeus ) 258 The Hyla pseudopuma Group 261 Hyla pseudopuma Giinther 262 Hyla pseudopuma pseudopuma Giinther 263 Hyla pseudopuma infucata Duellman 271 Hyla angustilineata Taylor 273 The Hyla rivularis Group _ 276 Hyla tica Starrett .... _ 278 Hyla rivularis Taylor 284 Hyla debilis Taylor ._ 289 Hyla xanthosticta Duellman 292 The Hyla pictipes Group 294 Hyla pictipes Cope _ 295 The Hyla uranochroa Group 301 Hyla uranochroa Cope 302 Hyla rufioculis Taylor 307 The Hyla lancasteri Group 311 Hyla lancasteri Barbour _ 312 The Hyla zeteki Group _ 318 Hyla picadoi Dunn 319 Hyla zeteki Gaige .. 323 The Hyla bogotensis Group _ _ 327 Hyla colymba Dunn 328 viii The Hyla salvadorensis Group — 332 Hyla legleri Taylor - 333 Hyla salvadorensis Mertens 337 The Hyla miliaria Group 341 Hyla valancifer Firschein and Smith — 342 Hyla echinata Duellman 346 Hyla fimbrimembra Taylor 348 Hyla thysanota Duellman 350 Hyla miliaria (Cope) — 352 The Hyla godmani Group 355 Hyla god7nani Giinther 356 Hyla loquax Gaige and Stuart 359 The Hyla picta Group 363 Hyla picta ( Giinther) — - — - 365 Hyla smithii Boulenger 368 The Hyla miotympanum Group — 370 Hyla miotympanum Cope - — 372 Hyla arborescandens Taylor — 380 The Hyla hazelae Group 384 Hyla hazelae Taylor 385 Hyla thorectes Adler - 388 The Hyla erythromma Group _ __ — 391 Hyla erythromma Taylor 392 The Hyla pinorum Group 395 Hyla mclanomma Taylor — 397 Hyla melanomma melanomma Taylor 398 Hyla melanomma bivocata Duellman and Hoyt _. — — - 402 Hyla pinorum Taylor 403 The Hyla sumichrasti Group 408 Hyla sumichrasti ( Brocchi ) 409 Hyla smaragdina Taylor 413 The Hyla mixomaculata Group 416 Hyla mixomaculata Taylor ___ 416 Hyla pellita Duellman 421 Hyla nubicola Duellman _ 423 Hyla mixe Duellman 425 The Hyla bromeliacia Group 429 Hyla bromeliacia Schmidt 429 Hyla dendroscarta Taylor 434 The Hyla taeniopus Group 437 Hyla chaneque Duellman 440 Hyla taeniopus Giinther 445 Hyla altipotens Duellman 450 The Hyla bistincta Group 453 Hyla bistincta Cope __ — . 457 Hyla pentheter Adler 462 Hyla charadricola Duellman 466 Hyla chryses Adler 468 Hyla robertsorum Taylor - — 470 Hyla pachyderma Taylor 473 Hyla siopela Duellman 475 Hyla crassa ( Brocchi ) 477 ix Hyla bogertae Straughan and Wright 479 The Hyla eximia Group — - 482 Hyla regilla Baird and Girard ----- — 484 Hyla regilla curia Cope — - 490 Hyla regilla hypochondriaca Hallowell 491 Hyla cadaverina Cope — 493 Hyla plicata Brocchi 496 Hyla eximia Baird 499 Hyla euphorbiacea Giinther - — 505 Hyla walkeri Stuart — - 510 The Hyla versicolor Group 513 Hyla arenicolor Cope 514 Genus Ptychohyla Taylor __. - 517 Ptychohyla schmidtorum Stuart _ - 527 Ptychohyla schmidtorum schmidtorum Stuart 527 Ptychohyla schmidtorum chamulae Duellman __. 531 Ptychohyla ignicolor Duellman — 532 Ptychohyla euthysanota ( Kellogg) 535 Ptychohyla euthysanota euthysanota (Kellogg) — 535 Ptychohyla euthysanota macrotympanum (Tanner) 539 Ptychohyla leonhardschultzei ( Ahl) - 541 Ptychohyla spinipollex ( Schmidt) _ _ - 544 Genus Plectrohyla Brocchi 547 Plectrohyla matudai Hartweg __ — - 559 Plectrohyla ixil Stuart 563 Plectrohyla sagorum Hartweg 566 Plectrohyla quecchi Stuart 569 Plectrohyla glandulosa ( Boulenger) 572 Plectrohyla pycnochila Rabb 575 Plectrohyla lacertosa Bumzahem and Smith 577 Plectrohyla avia Stuart 578 Plectrohyla guatemalensis Brocchi 580 Plectrohyla hartwegi Duellman - 583 Genus Smilisca Cope _- — 585 Smilisca baudinii (Dumeril and Bibron) 594 Smilisca cyanosticta ( Smith) — - 598 Smilisca phaeota ( Cope) - - 603 Smilisca puma ( Cope) 607 Smilisca sila Duellmann and Trueb — — 609 Smilisca sordida ( Peters ) 613 Genus Pternohyla Boulenger — - 618 Pternohyla dentata Smith 621 Pternohyla fodiens Boulenger - 624 Genus Triprion Cope . — 628 Triprion spatulatus spatulatus Giinther _ 629 Triprion spatulatus spatuatus Giinther 632 Triprion spatulatus reticulatus (Taylor) __ — — 636 Triprion petasatus ( Cope) - — 637 Genus Pseudacris Fitzinger — 641 Pseudacris clarkii ( Baird ) 642 Genus Acris Dumeril and Bibron — 645 Acris crepitans Baird 647 Nomina Dubita 649 Hyla cherrei Cope _ _ — - 650 Hyla molitor O. Schmidt _ 650 Hyla splendens O. Schmidt 651 Species Inquirienda — 651 Hyla species 651 Life History - 654 Breeding 654 Eggs - 657 Tadpoles 658 Duration of Development 659 Phylogeny and Zoogeography 660 Relationships of the Species 660 Zoogeography of Middle American Hylid Frogs 663 Ecological Distribution 663 Distribution within Habitats 666 Altitudinal Distribution 668 Geographical Distribution 671 Evolution of the Middle American Hylid Fauna 677 The Mesoamerican Hylids 678 The Neotropical Hylids 686 The Nearctic Hylids __ 691 The West Indian Hylids _ 692 Summary and Conclusions 694 Appendix 1 695 Appendix 2 __ 730 Literature Cited 736 Index _ 749 PLATES ( following index ) xi INTRODUCTION When the first erossopterygian crawled out of the rich Devonian waters and cast the first envious vertebrate gaze at the terrestrial world, a boundless empire awaited coloniza- tion. Although the change from an ungainly lobe-finned locomotion to a terrestrial walking gait, enhanced and made possible by drastic modifications and even loss of precious bones, was agonizingly slow, generations succeeded generations, archotypes gave way to new evo- lutionary experiments, and the land became the home for the first quadrupeds — the am- phibians. But this new environment was hos- tile to these aquatic emigrants who fought to avoid desiccation and faced the necessity to return to the water from which they had struggled in order to combine their genetic heritages in the production of a new genera- tion. Some kinds, although they had devel- oped lungs, eyelids, feet, and other assorted terrestrial adaptations, retreated to the placid life of the waters and slowly passed into evo- lutionary oblivion. Others faced the prob- lems of terrestrial existence by developing armour and further invaded the land only to resign themselves to the inevitable return to the water to provide the continuation and eventual extinction of their own kind. Somewhere, lost in the inextricable past of evolutionary history, one group of am- phibians deviated from those who retired to their primordial home and from those who haphazardly rushed ahead without the ad- vantage of the cleidoic egg. Perhaps at a time when the first reptilian rehearsal in ther- moregulation was taking place or maybe at the time of the sprouting of the first mam- malian hairs — it makes little difference — our little band of amphibian survivors struggled amidst a diverse lot of terrestrial creatures which had physiologically surpassed them. Among the many unsolved evolutionary mysteries few tingle the imagination more than those interactions between the environ- ment and the amphibian morphological adap- tations— all unrecorded in the fossil record — that resulted in the reduction of the number of vertebrae, the fusion of the postsacral verte- brae into a long inflexible rod, the loss of the tail, and the development of extraordinary long and powerful hind legs. Seemingly with- out predilection this group of amphibians leaped into the terrestrial scene, and the frog was born! Such bizarreness of structure is equalled in the tetrapods only by the turtles; both groups have had an illustrious and successful existence. The relative triumph of the frogs in comparison with the amphibians of less radi- cal posture is attested to by the vast array of living frogs, whereas most other groups of amphibians have long since abandoned their earlier conquests and remain now only as fragmentary designs in beds of shale. Not all non-saltatorial amphibians were so unfortu- nate, for by some unexplainable means a group of small, apparently relatively unmodi- fied tailed forms survived to become sala- manders and another group in a successful attempt to imitate earthworms lost their hard- earned limbs and took up a subterranean existence to survive as caecilians. But frogs were not content just to be frogs. Although in the beginning they still were chained to the water for purposes of repro- duction, they diversified and in so doing un- derwent many morphological and behavioral changes. They developed vocal cords and a membranous resonating chamber and learned to communicate, albeit crudely, but neverthe- less effectively for their purpose. They con- tinued their struggle against their aquatic bondage which they had inherited, and at several times in different places some of them broke the bonds and achieved terrestriality. But not all of the evolution was on land; the aquatic stages were not static. Swamps, lakes, marshes, and ponds were only the beginning. Rivers led away from the plains, and streams reached further into the highlands, where cold torrents awaited. By these aquatic avenues, dispersal was possible and life in new areas was achieved. And while the aquatic stages tested many schemes before developing the array of tadpoles known today, the frogs themselves hopped across the continents and reached every accessible corner of the globe where an ectotherm could live. Some settled in arid regions and modified their way of life and their structure so as to survive for months MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 on a small amount of invaluable water cleverly stored within their bodies. Others returned to the water and changed their ways to a strictly aquatic life, whereas most were con- tent to remain on land and to utilize the marshes, swamps, streams, and forests for their abodes. Some frogs explored the trees and found there an extensive and varied habitat, to which they adapted by modifying their fingers and toes, so as to be able to more effectively grasp the branches and leaves in their chosen home. One of these groups had an arciferal girdle and intercalary cartilages. Long after the evolution of these structures and the diversification of the group into perhaps 500 or so species, another highly successful evo- lutionary line listened to their nocturnal ca- cophony, instilled them in their stories and generations later studied them and called them Hylidae. Long before the amphibians arose, the earth was covered by extensive shallow seas sepa- rated by landmasses supporting only primitive plants. The imperceptible changes in the con- figurations of the land required millions of years during which time areas of land sepa- rated and drifted apart and the Atlantic Ocean was born between Africa and South America, and Australia and Antarctica shifted as Gond- wanaland disappeared below the waters of the Indian Ocean. By one and one-quarter million years ago, in the Cretaceous, the conti- nents of North America and South America were entirely separated from land in the rest of the world, except for an intermittent land bridge in the Bering Straits. At that time, North America was connected to South Amer- ica by a narrow link — Central America. Meager geological evidence indicates that in the upper Cretaceous, Central America was a moderately uplifted region enjoying equable climates. With the Laramide Revolution came changes — uplift of mountains, modification of climates, and consequent alteration of biotas. Sometime in the Eocene, the Bolivar Geo- syncline resulted in the separation of South America from Central America and North America. Throughout the Tertiary, especially in the Miocene and Pliocene, dramatic dis- turbances greatly changed the Americas. Lev- els of the oceans rose and receded; the Rocky Mountains and the Andes rose high above the clouds, and tropical climates retreated to- wards the lower latitudes leaving in some places nearly barren deserts in their wake. Recession of the seas and uplift of the land resulted in a reunification of South and Cen- tral America in the Pliocene. Mountains con- tinued to rise, as volcanos rose and spewed ash and lava over much of Central America. These tortuous events were not halted during the Pleistocene when sea levels and water tables rose and fell, climates changed, and glaciers formed on the higher mountains. The stage is basically the same, but the props have resulted in many different scenes. The hylid frogs are among the actors in a drama that has been continuing for many, many millennia. We, the biologists, have been able to glimpse a moment of the play and are faced with the challenge of interpreting not only the present but all of the earlier scenes. I find the challenge exciting, but am envious of my readers, the critics. The problems and principles of systemat- ics and zoogeography are intricately amalga- mated with those of evolution, the synthesis of all biology. The biochemists, physiologists, and embryologists can test many of their hypotheses by experimentation, but the con- clusions of the systematists and zoogeogra- phers can be reached only by observation, inferences, and extrapolation. New facts and interpretations continually result in minor ad- ditions to our knowledge and changes in our ideas. These facts and ideas emanate from the exploration of previously unstudied areas, the discovery of fossil faunas or even a single significant fossil, the intensive study of one or more biological problems in a single spe- cies or in an ecological community, and by the application of new methods of study. New insights into old problems can be gained by applying new techniques to a large, diverse, and widespread natural group of or- ganisms. Furthermore, the thorough study of the taxonomy and distribution of such groups provides the raw material for zoogeographic syntheses, which, in turn, can be applied to other groups of organisms. The conclusions of such studies each provides another small piece in the immense evolutionary puzzle. The hylid frogs are one of the most di- 1970 DUELLMAN: HYLID FROGS verse and widespread families in the Ameri- can tropics. Many of the species are common and easily studied; thus, the group affords an excellent subject for a systematic study. The size of the group — some 30 genera and per- haps 500 species — is too large to be treated monographically at one time. The results of my research presented here deal only with the species occurring in Middle America (Mexico and Central America). No comprehensive review of the Middle American hylids has been attempted pre- viously, although revisions of some of the genera (Duellman, 1956a; Funkhouser, 1957; Duellman, 1963c; and Duellman and Trueb, 1966) have appeared. During the preparation of the present monograph, I have become painfully aware of the necessity of obtaining much additional knowledge on the much larger and more diverse South American hy- Iid fauna, for therein lies the answer to many of the problems of relationships of the Middle American species. Although I have a keen interest in hylid frogs that has become more intense in the past decade, I must confess that the study of the hylids was begun as a means to gain a better understanding of Middle American zoogeog- raphy. In a large measure the research has been successful in that regard. However, equally exciting has been the unraveling of a variety of problems concerning the taxonomy and life history of many of the species. The purposes of the present publication are to 1) Describe accurately the taxa of Middle American hylid frogs and provide a means for their identification, 2) Assay the phylogenetic relationships of the genera and species, and 3) Evaluate the phylogenetic re- lationships and distributional data in a zoo- geographic synthesis. The taxonomic meth- odology utilized has included the usual array of external morphological characters, includ- ing wherever possible coloration in life, plus cranial osteology, tadpole morphology, mating calls, chromosome number, and various as- pects of the ecology, behavior, and life his- tory. My ideas on phylogenetic relationships differ markedly from some of those presented by other workers. This is due principally to the fact that most earlier workers did not utilize characteristics of the tadpoles, cranial osteology, and mating calls, all of which I have found to be extremely useful in deter- mining relationships. In synthesizing the dis- tributional and phylogenetic data I have crit- ically reevaluated the generally accepted zoo- geographic "truths" on the basis of new infor- mation, both biological and geological. Thus, by taking the attitude that nothing is sacred. I have come up with some interpretations that strongly differ from previous ideas. Perhaps my colleagues and succeeding generations of biologists will find some of my thoughts more than amusing and maybe even useful and justifiable. Probably every author of a systematic monograph wishes that his published results could be the "last word" on the group, but such is never the case. I am certain that addi- tional species await discovery in Middle America and that the information provided by such unknown species will alter some of my groupings and ideas of relationships. The discovery of tadpoles and analysis of calls still unknown to me most likely will result in further revisions. Thus, I beg my readers not to judge my work too harshly and to remem- ber that the material presented here makes their critical evaluation of new, as well as old, material a much easier task. ACKNOWLEDGMENTS The report of my researches embodied in the following pages is the result of innumer- able kindnesses and cooperation of many col- leagues^ associates, assistants, friends, and even total strangers. Through the years of my active work on the hylid frogs my debt of gratitude has grown to enormous proportions and were I to acknowledge each person adequately for his or her favors, I am afraid that I would have little or no room left for the frogs. During the past decade I have borrowed and even reborrowed hundreds of specimens from many collections and have visited all major collections in the United States at least once. For their efforts in my behalf, either by providing working space in their laboratories, loaning specimens to me, or both, I am grate- ful to Sr. Ticul Alvarez, Sr. Miguel Alvarez del Toro, Dr. Richard J. Raldauf, Dr. W. MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Frank Blair, Dr. Charles M. Bogert, Dr. James E. Bohlke, the late Dr. Doris M. Cochran, Dr. William G. Degenhardt, Dr. James R. Dixon, Dr. Charles L. Douglas, Dr. Josef Eiselt, Dr. Coleman J. Goin, Miss Alice G. C. Grandison, Dr. Jean Guibe, Dr. Robert F. Inger, Dr. Konrad Klemmer, Dr. John M. Legler, Dr. Alan E. Leviton, Dr. Richard B. Loomis, Mr. Hymen Marx, Sr. Eustorgio Mendez, Dr. George S. Myers, Dr. James A. Peters, Dr. Wilhelm Peters, Mr. Douglas C. Robinson, Dr. Douglas A. Rossman, Dr. Jay M. Savage, Dr. Hobart M. Smith, Dr. Robert C. Stebbins, Dr. Wilmer W. Tanner, Dr. Edward H. Tay- lor, Dr. Charles F. Walker, Dr. Ernest E. Wil- liams, Dr. John W. Wright, and Dr. Richard G. Zweifel. Although most of the colored photographs of frogs on which the colored plates were based were taken by me, some additional photographs — some of species that I did not have — were generously provided by Dr. Kraig Adler, Dr. Charles M. Bogert, Dr. Richard B. Loomis, Dr. John D. Lynch, Dr. Charles W. Myers, and Dr. Richard G. Zweifel. Dr. Loomis and Dr. David L. Jameson also pro- vided living frogs for illustrative purposes, and Dr. Myers contributed photographs re- produced herein as black and white plates. My work on the analysis of the mating calls was enhanced through the loans of tapes from Dr. W. Frank Blair, Dr. Charles M. Bogert, Dr. W. Ronald Heyer, Dr. David L. Jameson, Dr. Kenneth R. Porter, and Dr. Richard G Zweifel. Several persons contributed information from their own observations and gave me access to their field notes; thusly, I am in- debted to Dr. Kraig Adler, Dr. Jay M. Savage, Dr. Laurence C. Stuart, Dr. Charles F. Walker, Dr. Richard G. Zweifel, and especially Dr. Charles W. Myers. Furthermore, Dr. Savage made available to me manuscripts on aspects of his work on Costa Rican frogs and Dr. Alan E. Leviton provided helpful data on Hemipliractus. Dr. William F. Pyburn pro- vided tadpoles of two species. Had the collection of all of the data and specimens been left to me alone, the amount of available material would be considerably less than now exists. Several of my associates and students at the University of Kansas suf- fered long hours of hardship, often under most unpleasant conditions, in assisting me in the field or working independently in the field. For their efforts, I am grateful to Dr. Charles J. Cole, Dr. Arthur C. Echternacht, Dr. Laurence M. Hardy, Mr. Richard L. Hol- land, Mr. Dale L. Hoyt, Sr. Juan R. Leon, Dr. John D. Lynch, Dr. Craig E. Nelson, Dr. Jerome B. Tulecke, and Dr. John Wellman. Dr. Charles W. Myers and Dr. Linda Trueb were the greatest contributors in the field; together, often guided solely by Pan, we trod many distant ridges and explored many swamps and cascading streams; their aid and companionship cannot be adequately ac- knowledged by words alone. I am also grate- ful to Dr. J. Knox Jones, Jr. and Dr. James D. Smith, who in the course of their field work on mammals in Central America, took the time to collect many valuable frogs. My own field work was furthered by helpful sug- gestions by persons familiar with certain areas. Dr. Charles M. Bogert, Dr. Norman Scott, and Dr. Laurence C. Stuart directed me to choice localities in Oaxaca, Costa Rica, and Guatemala, respectively. Field work in the Middle American coun- tries was made possible by the generous co- operation of government officials, especially Ing. Rodolfo Hernandez Corzo of the Direc- cion General de Caza in Mexico and Sr. Jorge Ibarra, Director of the Museo Nacional de Historia Natural in Guatemala. Ing. Julio Aguirre C. provided comfortable working quarters at the Instituto Tropical de Investi- gaciones Cientificas in San Salvador and pro- vided guides and transportation to the moun- tains of northern El Salvador. Dr. Robert Armour, Assistant Director of the Escuela Agricola Panamericana at El Zamorano, Hon- duras, graciously provided plush quarters at the school and arranged for our stay on Cerro Uyuca. Dr. Alvaro Wille of the Universidad de Costa Rica provided invaluable aid in that country in 1961; at the same time Dr. Robert Hunter arranged for quarters at the Instituto Interamerican de Ciencia Agricolas at Tur- rialba and provided housing at Puerto Viejo. In 1965 and 1966, field work was facilitated by Dr. Stephen B. Preston of the Organization of Tropical Studies. Work in Panama was greatly facilitated by the cooperation of Mr. 1970 DUELLMAN: HYLID FROGS Marvin Keenan of the United States Army Environmental Health Unit at Fort Clayton, Dr. Martin H. Moynihan and Dr. Neal G. Smith of the Smithsonian Institute for Tropi- cal Research, and Dr. G. B. Fairchild and Dr. Martin D. Young of the Gorgas Memorial Laboratory. In addition, the field work was successful due to the kindnesses of many local residents, who provided housing, transporta- tion, guides, and often valuable specimens. Their generosity will be remembered long after the details of the frogs are forgotten. In the laboratory Miss Martha Crump and Mr. Bruce Curfman aided in collecting and tabulating data. Miss Crump and Mr. Robert R. Patterson prepared the osteological speci- mens, and Dr. Gerald R. Smith took necessary radiographs. To them I am deeply grateful for shortening my months of drudgery. The osteological data presented herein is the work of Dr. Linda Trueb, who examined all of the osteological material, aided in de- fining the groups, and helped me formulate the concepts of phylogenetic relationships. Her contributions to the study represent many laborious hours and a great deal of thought. I owe thanks to Mr. Jeffry Allen and Mr. Tom Swearingen for preparing the final maps and graphs. All line drawings and tone and color drawings reproduced as plates are the careful work of Mr. David M. Dennis. I have been fortunate to have such a skillful illustra- tor. Furthermore, I am grateful to Mr. Elmo Reiff of the Mid-Continent Engraving Com- pany, who provided much technical advice and painstaking care on the reproduction of the colored illustrations. A scientific paper of this magnitude can result only from the efforts of a skilled secre- tary. I have been fortunate in having the determined assistance of Mrs. Donna L. Ford, who transcribed my recorded text, corrected my grammar, proofread the copy, and then faithfully reproduced the final draft. She has my most profound thanks. Dr. Linda Trueb critically read the entire manuscript. Various sections of the manu- script were read by Sr. Juan R. Leon, Dr. John D. Lynch, Dr. Charles W. Myers, Dr. Lau- rence C. Stuart, Dr. Charles F. Walker, and Dr. Richard G. Zweifel. I am grateful for their comments and emphasize that errors of commission and omission are my responsibil- ity alone. Throughout the course of my work on the hylid frogs at the University of Kansas, I have been fortunate in being associated with con- siderate administrators. Dr. E. Raymond Hall, former Director of the Museum of Natural History, and Dr. A. Byron Leonard, former Chairman of the Department of Zoology, have released me from duties and helped to ar- range my schedule so that I could spend long periods of time in the field. Their enlightened attitudes made much of the work possible. I am indebted to Dr. Philip S. Humphrey, Di- rector of the Museum of Natural History, and to Mr. Irvin E. Youngberg of the Endowment Association, University of Kansas, for their encouragement and assistance in bringing this work to completion. For eight years, my research on Middle American hvlid frogs was supported by grants (G-9827, GB-1441, and GB 5818) from the Biomedical Sciences Section of the National Science Foundation. The publication of the colored plates was made possible by a grant (GN-640) from the Office of Science Infor- mation Service of the National Science Foun- dation. In this era of world crises it is com- forting to realize that the people of our nation through government agencies support a vast array of pure research. I only hope that in due time the results in the present publica- tion will justify part of the monetary expendi- ture. MATERIALS AND METHODS The material basis for this report is a total of 32,569 museum specimens of the 115 spe- cies of hylid frogs from Middle America, the accompanying field notes on many of these specimens, and recordings of their mating calls. I have examined 31,327 preserved frogs, 575 skeletons, 591 lots of tadpoles and 76 clutches of eggs of hylids from Middle Amer- ica, plus several hundred specimens from South America and some from the United States. The field work by my associates and me in Middle America resulted in the collec- tion of approximately 12,000 of these speci- mens, most of which are preserved in the Museum of Natural History at the University of Kansas. 6 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 All frogs collected by me and my asso- ciates were preserved in 10 per cent formalin and later transferred to 70 per cent ethyl alcohol. Specimens were fixed in trays with the knees spread, heels together, and fingers and toes spread, plantar surfaces down. Dried skeletons were prepared from preserved speci- mens or by means of dermestid beetles from carcasses dried in the field. Skeletal prepara- tions of small specimens (less than 40 mm. snout-vent length) were made by clearing the frogs in potassium hydroxide, staining the bones with alizarin red, destaining in potas- sium hydroxide, and storing them in glycerin. Dried skeletons were found to be wholly un- satisfactory for small species; when sufficient material was available, both dried and cleared and stained skeletal preparations were made of species having snout-vent lengths of 40 to 60 mm. All eggs and tadpoles were fixed and stored in 10 per cent formalin. Proper preservation of tadpoles is possible only if the specimens are not crowded in the con- tainer; preferably the original preservative is replaced with fresh formalin after about 24 hours. Measurements were taken with dial cali- pers and recorded to the nearest 0.1 mm. When possible, I measured only specimens that were fixed in the manner just described (usually those collected by me and my field associates). I found that measurements taken on uniformly preserved specimens were sub- ject to less variation than those on specimens fixed in various ways. Measurements usually were taken on one series of 20 to 25 males and as many females as available from a single locality. When sufficient specimens were not available from one locality, a sample was as- sembled from several localities in one area. In wide ranging species and in species having disjunct ranges, measurements were taken on samples from various parts of the range. Throughout the text several ratios of measure- ments to snout-vent length are given; where these ratios arc tabulated, snout-vent length is abbreviated S-V L. Developmental stages of tadpoles were determined from Gosner's ( 1960 ) develop- mental tables. In the course of my work on Middle American hylids, I have analyzed 731 record- ings of 76 species. Most of these recordings are in the bioacoustics laboratory in the Mu- seum of Natural History at the University of Kansas, but I have also utilized tapes from the collection at the University of Texas and at the American Museum of Natural History, plus a few tapes in the collection in the Museum of Zoology at the University of Michigan. My recordings were obtained by using a Magnemite (Model 610E and 610EV) with a tape speed of 15 inches per second, and a Uher (Model 4000-S) with a tape speed of 7M inches per second. Audiospectro- grams were made on a Vibralyzer ( Kay Elec- tric Company). The audiospectrograms re- produced here as plates 12-40 were all made using the narrow band of frequency. I have found that these displays more accurately show the nature of the call than do the wide band displays; this is especially true of the sections of the calls. In some cases, it is difficult or impossible to determine the pulse rate from audiospectrograms made on the narrow band frequency; in those cases, I made wide band audiospectrograms for pur- poses of determining pulse rate, but these have not been reproduced in the plates. Char- acteristics and measurements of the calls were obtained by using a grid marked on a plastic overlay on top of the audiospec- trograms. In tables, cycles per second is ab- breviated cps. The synonymy given at the beginning of each generic account includes only references to the original description of the genus and other genera that are considered to be synon- ymous. The type species is listed for each. The synonymies at the beginning of each species account include the reference to the original description of that species and all other species and subspecies that are consid- ered to be junior synonyms. In addition, the following standard references on Middle American hylids are listed, where appropriate, in the synonymies: Boulenger (1882a), Broc- chi (1882),' Giinther (1885-1902), Kellogg (1932), Smith and Taylor (1948), Stuart (1963), and Taylor ( 1952c ) . References to each gen- eric and specific, or subspecific, combination of names is given. Furthermore, if the species is included in a group that has been recently revised or monographed, a reference to such 1970 DUELLMAN: HYLID FROGS publication is given. The synonymies are an- notated to include the catalogue number and depository of type specimens, the type local- ity, and the collector of the type specimens. The synonymies also contain references to publications in which names are synonymized or transferred from one genus to another. All references in a synonymy are given only to author, date, and page. The complete citations for these references are given in the Literature Cited. The locality records for the various species and subspecies have been plotted on maps. All localities that could be found have been plotted, but due to the crowding of symbols, some localities have been covered by one symbol. The Map of Hispanic America (Scale 1:1,000,000) published by the Ameri- can Geographical Society has been my pri- mary source, but other maps and atlases have been consulted. Specimens examined are listed in Appen- dix 1. Throughout the text and appendices, specimens are listed with their catalogue num- bers and abbreviations for the museum or private collections, as follows: A.M.N.H., The American Museum of Natural History A.N.S.P., Academy of Natural Sciences of Philadelphia B.M.N.H., British Museum (Natural History), London B.Y.U., Brigham Young University C.A.S., California Academy of Sciences C.J.G., Coleman J. Goin, Gainesville, Florida CM., Carnegie Museum, Pittsburgh E.H.T.-H.M.S., Edward H. Taylor-Hobart M. Smith, Lawrence, Kansas F.A.S., Frederick A. Shannon, Wickenberg, Arizona F.M.N. H, Field Museum of Natural History G.M.L., Gorgas Memorial Laboratory, Pan- ama City I.P.N., Instituto Politecnico Nacional, Mexico City K.U., University of Kansas Museum of Nat- ural History L.A.C.M., Los Angeles County Museum L.B.S.C, Long Beach State College L.S.U., Louisiana State University, Museum of Zoology M.C.Z., Museum of Comparative Zoology, Harvard M.d.L.S., Museo de La Salle, Bogota, Colom- bia M. M., Magdeburg Museum, Germany M.N.H.N., Museum National d'Histoire Nat- urelle, Paris M.V.Z, Museum of Vertebrate Zoology, Berke- ley M.Z.T.G., Museo de Zoologia Tuxtla Gutier- rez, Mexico N.H.R.M., Naturhistoriska Riksmuseet, Stock- holm N.M.W., Naturhistorisches Museum Wien, Vienna R.C.T., Richard C. Taylor, Lawrence, Kansas R.H., Ratibor Hartmann, Finca Santa Clara, Panama S.D.N.H.M., San Diego Natural History Mu- seum S.N.M., Senckenbergische Natur-Museum, Frankfurt-am-Main, Germany S.U., Stanford University T.C.W.C., Texas Cooperative Wildlife Collec- tion, Texas A&M University T.N.H.M., Texas Natural History Museum, University of Texas U.C.R., Universidad de Costa Rica, San Jose U.F., University of Florida U.I.M.N.H., University of Illinois Museum of Natural History U.M.M.Z., University of Michigan Museum of Zoology U.N.M., University of New Mexico U.S.C., University of Southern California U.S.N.M., United States National Museum U.U., University of Utah Z.M.B., Zoologisches Museum, Berlin The color illustrations (pis. 41-72) are water-color reproductions drawn from color transparencies taken in the field, principally by the author, with a Kine Exacta camera. The four-color engravings were made at the Mid-Continent Engraving Company in Wich- ita, Kansas. The individual figures on each color plate are identified only to species and scale. The museum number and locality for the specimens depicted in the plates are given in Appendix 2. 8 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 HISTORICAL RESUME A review of the history of our knowledge of Middle American hylids reveals that there have been three major periods. During the first period (1853-1900) most of the work on hylids was done by a few herpetologists — chiefly George A. Boulenger, Paul Brocchi, Edward D. Cope, and Albert C. L. Giinther — working with relatively few specimens col- lected by other persons. These workers sel- dom had any knowledge of the appearances of the frogs in life, nor did they possess much, if any, information on the habitats or life histories of the frogs. During the second period (1920-1941) an increased number of herpetologists worked on Central American hylids, and the chief contributors to our knowledge — Emmett R. Dunn, Karl P. Schmidt, Hobart M. Smith, Laurence C. Stu- art, and Edward H. Taylor — collected most of their own material; consequently, new kinds of data (colors in life, habitats, and life histories) were utilized. The third period (1947-present) is an intensified continuation of the second period. However, the third period differs from the others by being a time of synthesis and interpretation, which has been made possible by quantities of speci- mens, knowledge of the frogs in their natural environments, and the utilization of new kinds of information, such as voice analysis, cyto- genetics, and comparative osteology. Herpetological exploration in Middle America lagged behind that in North and South America by about half a century. Lin- naeus (1758) and Laurenti (1768) named several species of South American frogs; many of these were based on illustrations in Seba's (1734) "Thesaurus." Three species — Hyla boans, H. rubra, and Phrynohyas venulosa — occur in Central America. Spix (1824) and Wied (1824b) named several species of frogs from South America; of those named, Hyla crepitans Wied, occurs in Central America. Many herpetological specimens were ob- tained for the United States National Museum by various members of the field parties con- ducting the United States and Mexican Boundary Survey from 1851 to 1854. These collections provided the type specimens of Hyla affinis and H. vanvlietii Baird (1854) and Hyla nebulosa Hallowell (1854). The first species of hylid named from Middle America was Hyla baudinii from "Mexique" (Dumeril and Bibron, 1841); the type is in the Museum National d'Histoire Naturelle in Paris. Another collection re- ceived by the museum in Paris was made by Arthur Morelet in El Peten and Alta Verapaz, Guatemala; his collection contained the speci- men that became the type of Hyla moreletii (Dumeril, 1853). Major William Rich sent a collection of amphibians from Mexico City to the United States National Museum in 1853. In the collection were two specimens that became the syntypes of Hyla eximia Baird (1854). Baron J. von Warzewicz made important botanical collections and obtained many species of amphibians in western Pan- ama. The amphibians were sent to the Kra- kow Museum in Poland. Oscar Schmidt (1857) gave brief Latin diagnoses for several new species, including Hyla ynolitor, H. pug- nax, and H. splendens, and in 1858 provided extensive descriptions and illustrations of the new species. Some of Warzewicz's collection reached the Zoologisches Museum in Berlin; Wilhelm Peters (1863) named Hyla sordida from "Veraguas," Panama. Other collections were received in Berlin, and among the new species named from Mexico was Hyla micro- tis Peters. The most prolific writer on Middle Amer- ican hylids in the last half of the Nineteenth Century was Edward D. Cope, who between 1862 and 1894 named 31 species and five genera of hylid frogs from Middle America. Among Cope's more important contributions are his report on the Costa Rican collections made by William M. Gabb and the Nicara- guan collections assembled by J. A. McNiel and J. F. Bransford. Most of the collections studied by Cope had been received by the United States National Museum; most of the types of Cope's species are in that museum, but some are in the Academy of Natural Sci- ences of Philadelphia, whereas the location of others is unknown. The first Middle American hylids to reach the British Museum apparently were those in a collection made by Auguste Salle in Vera- cruz, Mexico; specimens in this collection formed the type series of Hyla euphorbiacea Giinther, 1859. At about this time Osbert 1970 DUELLMAN: HYLID FROGS 9 Salvin and Frederick D. Godman initiated their expeditions to Mexico and northern Cen- tral America. Salvin's first trip to Alta Verapaz, Guatemala, resulted in the description of Hyla holochroa (Salvin, 1860). Godman and vari- ous associates (Herbert H. Smith, C. T. Hoege, and Mateo Trujillo) collected in many parts of southern Mexico; Salvin and Godman both collected in Guatemala and other parts of Central America; in later years (1879 and 1880), O. C. Champion continued their field work in Guatemala (see Godman, 1915, for itineraries ) . Alphonso Forrer made important collections from Sinaloa, Mexico. The ex- plorations by Salvin and Godman, and their associates, resulted in the material basis for the "Biologia Centrali-Americana." Albert C. L. Giinther prepared the volume on the rep- tiles and amphibians, which was issued in parts between 1885 and 1902 (accounts of 48 hylids in 1901 and 1902). By this time the explorations in Middle America had acquired specimens that became the types of 14 species named by Giinther and George A. Boulenger; the latter included much of the new material in his "Catalogue of the Batrichia Salientia . . ." published in 1882, in which he listed 38 species of hylids from Mexico and Central America. The counterpart of the British biological investigation in Middle America was the French "Mission Scientifique au Mexique et dans l'Amerique Centrale" decreed by Na- poleon III in 1864. Marie-Firmin Bocourt was the chief naturalist attached to the commis- sion, and Adolphe Boucard was a member of at least one of the exploration parties, which worked in Mexico and Guatemala from 1865 to 1867. All of the specimens were deposited in the Museum National d'Histoire Naturelle in Paris. The amphibians were studied by Paul Brocchi, who published descriptions of five new species in 1877 and 1879 and sum- marized the amphibians of the Mission Scien- tifique in his "Etude des Batraciens de l'Ame- rique Centrale," published in 1882. Brocchi listed 31 species of hylids. Additional Mexi- can specimens were reported by M. F. Moc- quard in 1889. Thus, at the dawn of the Twentieth Cen- tury the first period of herpetological explora- tion had been completed. The new century witnessed only the minor amphibian collec- tions made by Edward W. Nelson and Ed- ward A. Goldman in Mexico (reported by Remington Kellogg in 1932) and a few small collections sent to the United States National Museum where Leonhard Stejneger (1906, 1911, and 1917) named four species of hylids. Essentially for the first quarter of the Twen- tieth Century, the fertile herpetological fields of Middle America lay fallow, except that the American Museum of Natural History sent an expedition to the Caribbean lowlands of Nica- ragua in 1916; the amphibians were reported on by Noble (1918). Many amphibians were obtained in Darien, Panama, by Charles M. Breder, Jr. as a member of the Marsh-Darien Expeditions of The American Museum of Nat- ural History in 1924; Emmett R. Dunn (1934) named one new species of Hyla from the col- lection, and Breder (1946) presented a sum- mary of the life history data. Between the late 1920's and World War II, North American herpetologists began a second biological conquest of Middle Amer- ica. Emmett R. Dunn explored the fauna in Costa Rica and Panama, and Karl P. Schmidt made important collections in Guatemala and Honduras. Between them, they discovered and named seven new hylids from Central America in as many years. The collections made by Dunn were deposited in the Acad- emy of Natural Sciences of Philadelphia, the American Museum of Natural History, and the Museum of Comparative Zoology at Har- vard University, whereas those made by Schmidt were deposited in the Field Museum of Natural History. The first Mexican expedition by the Mu- seum of Zoology at the University of Michigan was conducted by Alexander G. Ruthven in 1911, and Helen T. Gaige collected in Panama in 1923, but that institution did not intensify its Middle American program until the 1930's. James A. Oliver made important collections in Colima, Mexico, in 1935 and with Norman Hartweg studied the herpetofauna of the Pacific slopes of the Isthmus of Tehuantepec, Mexico. In 1940 and 1941, Hartweg made important collections in Chiapas. In 1933, Laurence C. Stuart began his studies of the Guatemalan herpetofauna that have contin- ued to the present time and resulted in many 10 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 faunal studies, descriptions of new species (including four Plectrolujla and one Ptycho- hyla), and in 1963, a checklist of the Guate- malan herpetofauna. In 1932, Edward H. Taylor initiated his studies on the amphibians and reptiles of Mexico. Joined in his researches by Hobart M. Smith, he named and described 24 species of Mexican hylids from 1937 to 1945. From 1939 to 1941, Smith collected in Mexico under the auspices of the Walter Rathbone Bacon Travelling Fellowship of the Smithsonian In- stitution. The large collections of amphibians were deposited, for the most part, in the United States National Museum and reported on by Taylor and Smith (1945). The earlier material collected in Mexico by Smith and Taylor formed a part of the Edward H. Taylor-Hobart M. Smith collection. Approxi- mately half of this collection was later de- posited in the Museum of Natural History at the University of Illinois; in 1959, most of the other half was sold to the Field Museum of Natural History. The amphibian fauna of Mexico was summarized by Smith and Tay- lor in 1948; they listed 55 species of hylids from Mexico. After World War II, with the advent of new roads in Middle America and financial support for biological investigations, herpe- tologists began swarming into Mexico in the late 1940's and into Central America about a decade later. Laurence C. Stuart continued his studies in Guatemala, whereas Edward H. Taylor began a study of the herpetofauna of Costa Rica. Taylor collected in Costa Rica in 1947, 1951, 1952, and 1954; his collections were deposited in the Museum of Natural History at the University of Kansas. In 1947, Taylor was accompanied by Richard C. Tay- lor, who kept his collections apart from those deposited at the University of Kansas. Later R. C. Taylor's collections were sold to the Field Museum of Natural History. Taylor (1952c, 1954b, 1955, and 1958) reviewed the amphibians of Costa Rica and named 15 spe- cies of hylids. The post-war period of discovery has continued to the present time due to efforts of collectors in reaching isolated areas that previously had not been collected. Most of the species of hylids named from Middle America in the past decade are montane species. By 1968, 187 hylid frogs had been named from Middle America (fig. 1; table l).1 The trend curve for the rate of species de- scription of Middle American hylids is nearly like that for the entire family throughout its world-wide range (Steyskal, 1965). In the 1950's began a period of synthesis and review of genera and species groups; thus, the genus Phnjnohyas was reviewed by Duellman (1956a), Phyllomedusa by Funk- houser (1957), Ptychohyla by Duellman (1963c), and Smilisca by Duellman and Trucb (1966). The University of Michigan and the University of Illinois continued to concentrate on the Mexican and Guatemalan faunas, and a group of biologists at the Uni- versity of Southern California, under the enthusiastic direction of Jay M. Savage, be- gan an intensive study of the Costa Rican herpetofauna. The early post-war emphasis at the University of Kansas was on Mexico and Costa Rica; but later the work in Mexico diminished as Central American areas were emphasized. Excellent collections of Middle American hylids are present in North American mu- seums, but pitifully few specimens are repre- sented in Middle American collections. The Institute Politecnico Nacional and the Museo de Zoologia de Tuxtla Gutierrez in Mexico, the Museo Nacional de Historia Natural in Guatemala, the Institute de Investigaciones Tropicales at the Universidad de El Salvador, the Museo de Zoologia de la Universidad de Costa Rica, and the Gorgas Memorial Labora- tory in Panama have small collections. In the past decade we have observed a change from museum-oriented work to field- oriented research. Increasingly more atten- 1 Two specific names originally proposed in the genus Hyla in Middle America are now considered to belong to the leptodactylid genus Eleuthcrodactylus. These are Hyla punctariola O. Schmidt (1857) and //. chica Noble (1918); the latter is a synonym of Eleutlicrodactylus diastema. Gunther ( 1901 ) named Hyla mocquardi from "Guatemala or Panama"; Duell- man (1968c) showed that mocquardi was a member of the South American Hyla pulchclla group and should not be considered as a member of the Middle American herpetofauna. Taylor ( 1952a ) named Hyla shrevei from Panama; Goin (1959) demonstrated that the type of shrevei was actually a mislabeled Hyla wilderae. 1970 DUELLMAN: HYLID FROGS 11 n r 1840 50 60 70 80 90 1900 10 20 30 40 50 60 70 YEARS Fig. 1. Number of species and subspecies of hylid frogs named from Middle America from 1841 through 1968. The bars represent the number of names proposed in each year; the line represents the cumulative num- ber of taxa considered to be valid. Middle American ta.xa discovered in, and name from, the United States and from South America, replacement names for earlier names that are preoccupied, and nomina nuda are not in- cluded; nomina dubita are not included in the line. tion is being given to life histories (Starrett, 1960a) and interactions between species, es- pecially regarding the importance of voice in frogs (Fouquette, 1960b; Duellman, 1967c). These kinds of studies have complemented the faunistic surveys and have added a wealth of supplemental data to museum specimens. My own early work in Middle America was not directed towards the study of hylid frogs, although an interest in these frogs soon developed. My first collections in Mexico were made in the summer of 1951, when I traversed the Sierra de Coalcoman in Michoa- can to the Pacific coast and also worked briefly in Nayarit. In 1955, I returned to western Mexico for two months and collected in the Tepalcatepec Valley and the Sierra de Coalcoman in Michoacan and briefly at Oaxaca and Tehuantepec in the state of Oaxaca. Seven months were spent in Mexico in 1956; the country was traversed in both rainy and dry seasons, and only the peninsulas of Baja California and Yu- catan were neglected. January and early February of 1958 were spent in the cloud forests of eastern Mexico in an effort to secure hylids. The same areas were worked again during a two-month visit to Mexico in the summer of 1958, but most of the time was spent in the Isthmus of Tehuantepec. In March and April of 1959 a brief, but profit- able, trip was made into the Sierra de Juarez in northern Oaxaca. All material collected up to that time was deposited in the Museum of Zoology at the University of Michigan. In September, 1959, my studies on the Middle American hylid frogs received sup- port from the National Science Foundation and were centered at the Museum of Natural History at the University of Kansas. All speci- mens henceforth collected were deposited in that museum. A brief trip was made to the cloud forests of eastern Mexico in December, 1959; I was accompanied by Dale L. Hoyt and John Wellman, and we succeeded in obtain- ing needed material of the bistincta, miotym- panum, and taeniopus groups of Hyla. In Feb- ruary and March, 1960, J. Knox Jones, Jr. and 12 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TABLE 1 Alphabetical Synonymy of Middle American Hylid Frogs Trivial name, original generic name, author, and date Present name adipoventris ( Ptychohyla ) Taylor, 1944 _ Ptijchohyla leonhardschultzei affinis (Hyla) Baird, 1854 (nee Spix) Hylaarenicolor alcomi (Agalychnis) Taylor, 1952.. Pachymedusa dacnicolor alleei (Hyla) Taylor, 1952 Hyla uranochroa altae (Hyla) Dunn, 1933 Hyla stanfferi altae altipotens ( Hyla ) Duellman, 1968 _ Hyla altipotens alvaradoi (Hyla) Taylor, 1952 Hyla colymba angustilineata (Hyla) Taylor, 1952 Hyla angustilineata annae (Phyllomedusa) Duellman, 1963 — . Agalychnis annae arborescandens ( Hyla ) Taylor, 1939 Hyla arborescandens arboricola (Hyla) Taylor, 1941 Hylaeximia arenicolor (Hyla) Cope, 1866... Hylaarenicolor avia (Plectrohyla) Stuart, 1952 Plectrohyla avia axillamembrana ( Hyla ) Shannon and Werler, 1955 Hyla loquax azteca (Hylella) Taylor, 1943 Hyla smaragdina baudinii (Hyla) Dumeril and Bibron, 1841 _ ._. Smilisca baudinii beltrani ( Hijla ) Taylor, 1942 Smilisca baudinii biseriata (Hyla euphorbiacea) Lynch, 1964 nomen nudum bistincta (Hyla) Cope, 1877 Hyla bistincta bivocata (Hyla) Duellman and Hoyt, 1961 Hyla melanommabivocata boans (Rana) Linnaeus, 1768 ~- Hylaboans bocourti (Hyla) Mocquard, 1899 Hyla euphorbiacea bogertae (Hyla) Straughan and Wright, 1969 Hyla bogertae bogerti (Ptychohyla) Taylor, 1949 _ Ptychohyla euthysanota euthysa- nota boulengeri (Scytopis) Cope, 1887 Hylaboulengeri brachycephala (Plectrohyla) Taylor, 1949 . . Plectrohyla matudai bromeliacia ( Hyla ) Schmidt, 1933 Hyla bromeliacia bromeliana (Hyla) Taylor, 1939 Hyla taeniopus bufonia (Hyla) Spix, 1824 Phrynohyas venulosa cadaverina (Hyla) Cope, 1866 __~ Hyla cadaverina calcarifer (Agalychnis) Boulenger, 1902 Agalychnis calcarifer californiae (Hyla) Gorman, 1960 .... Hyla cadaverina callidryas (Hyla) Cope, 1862 Agalychnis callidryas cardenasi (Hyla) Taylor, 1939 Hylaeximia ceratophrys (Hyla) Stejneger, 1911 Gastrotheca ceratophrys chamulae (Ptychohyla) Duellman, 1961 Ptychohyla schmidtorum chamulae chaneque (Hyla) Duellman, 1961 Hyla chaneque charadricola (Hyla) Duellman, 1964 Hyla char adricola cherrei (Hyla) Cope, 1894 nomen dubium chryses (Hyla) Adler, 1965 _. - Hylachryses clarkii (Helocaetes) Baird, 1854 Pseudacris clarkii colymba (Hyla) Dunn, 1931 Hyla colymba copii ( Hyla ) Boulenger, 1887 Hyla arenicolor corasterias (Phrynohyas) Shannon and Humphrey, 1957 .. - Phrynohyas venulosa coronata (Gastrotheca) Stejneger, 1911 .._ Anotheca spinosa 1970 DUELLMAN: HYLID FROGS TABLE 1 — (Continued) 13 Trivial name, original generic name, author, and date Present name cotzicensis (Plectrohyla) Stuart, 1948 Plectrolujla glandulosa crassus (Cauphias) Brocchi, 1877. Hyla crassa crepitans (Hyla) Wied, 1824 Hyla crepitans crepitans (Acris) Baird, 1854 Acris crepitans culex (Hyla) Dunn and Emlen, 1932 Hyla staufferi staufferi cnrta ( Hyla ) Cope, 1866 _... Hyla regilla curta cyanosticta (Hyla phaeota) Smith, 1953 ._.. Smilisca cyanosticta cyclomaculata (Hyla) Taylor, 1949 Hyla taeniopus dacnicolor (Phyllomedusa) Cope, 1864 Pachymediisa dacnicolor dalqnesti (Hyla) Taylor, 1949 Hyla taeniopus darlingi ( Hyla ) Smith, Smith, and Werler, 1952 Hyla miotympanum daulinia (Hyla) Cope, 1865 Smilisca baudinii debilis (Hyla) Taylor, 1952 Hyla debilis dendroscarta (Hyla) Taylor, 1940 Hyla dendroscarta dentata (Pternohyla) Smith, 1957 Pternohyla dentata deserticola ( Hyla regilla ) Jameson, et al., 1966 Hyla regilla hypochondriaca digueti (Hyliola) Mocquard, 1899 Hyla are tricolor dolomedes (Hyla baudinii) Barbour, 1923 Smilisca phaeota duellmani (Hyla) Lynch and Smith, 1966 Hyla chaneque dulcensis (Hyla) Taylor, 1958 Hyla elaeochroa ebraccata (Hyla) Cope, 1874 Hyla ebraccata echinata (Hyla) Duellman, 1962 Hylaechinata elaeochroa (Hyla) Cope, 1876 Hyla elaeochroa erythromma (Hyla) Taylor, 1937 Hylaerythromma euphorbiacea (Hyla) Giinther, 1859 Hyla euphorbiacea euthysanota (Hyla) Kellogg, 1928 Ptychohyla euthysanota euthysa- nota eximia (Hyla) Baird, 1854 Hylaeximia fimbrimembra ( Hyla ) Taylor, 1948 Hyla fimbrimembra fodiens (Pternohyla) Boulenger, 1882 Pternohyla fodiens foliamorta ( Hyla ) Fouquette, 1958 Hyla rostrata forbesi ( Hyla ) Taylor, 1940 Hyla arborescandens gabbii (Hyla) Cope, 1876 Smilisca sordida glandulosa (Hyla) Boulenger, 1883 Plectrohyla glandulosa godmani (Hyla) Giinther, 1901 Hyla godmani gracilipes (Hyla) Cope, 1865 Hylaeximia guatemalensis (Plectrohyla) Broechi, 1877 Plectrohyla guatemalensis hartwegi (Plectrohyla) Duellman, 1968 Plectrohyla hartwegi hazelae (Hyla) Taylor, 1940 Hylahazelae helenae (Agalychnis) Cope, 1885 Agalychnis callidryas holochroa (Hyla) Salvin, 1860 Agalychnis mo reletii hypochondriaca (Hyla scapularis var. ) Hallowell, 1854 Hyla regilla hypochondriaca ignicolor (Ptychohyla) Duellman, 1961 Ptychohyla ignicolor immensa (Hyla) Taylor, 1952 Hyla miliaria inflata (Acrodytes) Taylor, 1944 Phrynohyas venulosa infucata ( Hyla pseudopuma ) Duellman, 1968 Hyla pseudopuma infucata ixil (Plectrohyla) Stuart, 1942 Plectrohyla ixil labeculata (Hyla bistincta) Shannon, 1951 Hyla bistincta 14 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TABLE 1— (Continued) Trivial name, original generic name, author, and date Present name lacertosa (Plectrohyla) Bumzahem and Smith, 1954 „ - Plectrohylalacertosa lafrentzi (Hyla) Mertens and Wolterstorff, 1929 Hyla plicata lancasteri (Hyla) Barbour, 1928 Hyla lancasteri laticeps {Hyla regilla) Cope, 1889 Hylaregilla carta latifasciata (Phrynohyas) Duellman, 1956 Phrynohyas venulosa legleri (Hyla) Taylor, 1958 - Hylalegleri lemur (Phyllomednsa) Boulenger, 1882 .. - Phyllomedusa lemur leonhardschultzei (Hyla) Ahl, 1934... Ptychohyla leonhardschultzei lichenosa (Hyla) Gunther, 1859 .— Phrynohyas venulosa litodryas (Phyllomedusa) Duellman and Trueb, 1967 .. . Agalychnis litodryas loquax (Hyla) Gaige and Stuart, 1934 Hylaloquax lythrodes (Hyla) Savage, 1968.... ~- Hyla rufioculis macrotympanum ( Hyla ) Tanner, 1957 - Ptychohyla euthysanota macrotym- panum manisorum (Hyla) Taylor, 1954 Smilisca baudinii marmorata (Hyla molitor var.) Schmidt, 1857 .. nomendubium martini (Hyla microcephala) Smith, 1951 .. __ Hyla microcephala underwoodi matudai ( Plectrohyla ) Hartweg, 1941 .. - Plectrohyla matudai maxima (Rana) Laurenti, 1768 Hylaboans melanomma (Hyla) Taylor, 1940 ... Hyla melanomma melanomma microcephala (Hyla) Cope, 1886 . Hyla microcephala microcephala microcephala (Hyla) Boulenger, 1898 (nee Cope) . . Hyla microcephala underwoodi microeximia (Hyla) Maslin, 1957 ~~~ Hylaeximia microtis (Hyla) Peters, 1869 .. Hyla miotympanum miliarias (Hypsiboas) Cope, 1886 . Hyla miliaria milled (Hyla) Shannon, 1951 .. Ptychohyla leonhardschultzei miotympanum (Hyla) Cope, 1863 Hyla miotympanum mixe (Hyla) Duellman, 1965 Hyla mixe mixomaculata (Hyla) Taylor, 1950 Hyla mixomaculata modesta (Acrodytes) Taylor and Smith, 1945 Phrynohyas venulosa moesta (Hyla punctariola) Cope, 1876 ...- Hyla pictipes molitor (Hyla) Schmidt, 1857 . nomendubium monticola (Hyla punctariola) Cope, 1876 . Hyla pictipes moraviaensis (Hyla) Taylor, 1952 . . Hyla lancasteri moreletii (Hyla) Dumeril, 1853 .__ Agalychnis moreletii muricolor (Hyla) Cope, 1862 ..... Smilisca baudinii nana (Hyla) Gunther, 1901 (nee Boulenger) ..... Hyla smithii nebulosa (Hyla) Hallowell, 1854 (ncc Spix) . Hyla cadaverina nicefori (Gastrotheca) Gaige, 1933 . - Gastrotheca nicefori nigripes ( Hyla ) Cope, 1876 ... Smilisca sordida nigropunctata (Hyla) Boulenger, 1882 ... Phrynohyas venulosa nubicola (Hyla) Duellman, 1964 Hylanubicola oaxacae (Hyla bivocata) Lynch, 1964 nomen nudum pachyderma (Hyla) Taylor, 1942 .. Hyla pachy derma paenulata (Hyla) Brocchi, 1881 Phrynohyas venulosa panamemis (Cerathyla) Stejneger, 1917 Hemiphractus panamensis pansosana (Hyla) Brocchi, 1877 Smilisca baudinii pellita ( Hyla ) Duellman, 1968 Hyla pellita 1970 DUELLMAN: HYLID FROGS TABLE I— (Continued) 15 Trivial name, original generic name, author, and date Present name pentheter ( Hyla ) Adler, 1965 Hyla pentheter petasatus ( Pharyngodon ) Cope, 1865 ..... Triprion petasatus phaeota (Hyla) Cope, 1862 Smilisca phaeota phantasmagoria (Hyla) Dunn, 1943 Hyla miliaria phlebodes (Hyla) Stejneger, 1906 Hyla phlebodes picadoi (Hyla) Dunn, 1937 Hyla picadoi picta (Hylella) Gunther, 1901 Hyla picta pictipes (Hyla) Cope, 1876 Hylapictipes pinorum (Hyla) Taylor, 1937 Hyla pinorum platycephala (Hylella) Cope, 1879 ..... Hyla sumichrasti plicata (Hyla) Brocchi, 1877. Hyla plicata proboscidea (Hyla) Taylor, 1948 (nee Brongersma) Hyla taeniopus pseudopuma (Hyla) Gunther, 1901..... Hyla pseudopuma pseudopuma pugnax (Hyla) Schmidt, 1857 Hyla crepitans puma (Hyla) Cope, 1885 Smilisca puma pynochila (Plectrohyla) Rabb, 1959 Plectrohyla pynochila quecchi (Plectrohyla) Stuart, 1942 .... Plectrohyla quecchi quinquevittata (Hyla) Cope, 1886 Hyla elaeochroa resinifictrix (Hyla) Goeldi, 1907 Phrynohyas venulosa reticidata (Diaglena) Taylor, 1942 Triprion spatulatus reticulatus richardi (Hyla) Taylor, 1948 (nee Baird) Hylafimbrimembra richardtaylori ( Hyla ) Taylor, 1954 Hyla fimbrimembra rickardsi (Hyla) Taylor, 1939 Hyla godmani rivularis (Hyla) Taylor, 1952 Hyla rivularis robertmertensi (Hyla) Taylor, 1937 Hylarobertmcrtensi robertsorum (Hyla) Taylor, 1940 Hyla robertsorum robustofemora ( Hyla ) Taylor, 1940 Hyla crassa rosenbergi ( Hyla ) Boulenger, 1898 Hyla rosenbergi rostrata (Hyla) Peters Hyla rostrata rozellae (Hyla) Taylor, 1942 Ptychohyla euthysanota euthysa- nota rubra ( Hyla ) Laurenti, 1768 Hyla rubra rudis (Hyla) Moequard, 1899 Pternohyla fodiens rufioadis (Hyla) Taylor, 1952 Hyla rufioculis rufitela ( Hyla ) Fouquette, 1961 Hyla rufitela sagorum (Plectrohyla) Hartweg, 1941 Plectrohyla sagorum saltator (Agalychnis) Taylor, 1955 Agalychnis saltator salvadorensis (Hyla) Mertens, 1952 .... Hyla salvadorensis salvini (Hyla) Boulenger, 1882 Smilisca sordida schmidtorum (Ptychohyla) Stuart, 1954 Ptychohyla schmidtorum schmidt- orum sila (S7iiilisca) Duellman and Trueb, 1966 Smilisca sila siopela (Hyla) Duellman, 1968 .. Hyla siopela smaragdina (Hyla) Taylor, 1940 ..... Hyla smaragdina smithii (Hyla) Boulenger, 1902... Hylasmithii sordida (Hyla) Peters, 1863 Smilisca sordida spatulatus ( Triprion ) Gunther, 1882 Triprion spatulatus spatulatus spilomma (Hyla) Cope, 1877 Phrynohyas venulosa 16 MONOGRAPH MUSEUM OF NATURAL HISTORY TARLE I— (Concluded) NO. 1 Trivial name, original generic name, author, and date Present name spinipollex (Hyla) Schmidt, 1936 Ptychohyla spinipollex spinosa (Hyla) Steindachner, 1864—. Anotheca spinosa splendens (Hyla) Schmidt, 1857 nomen dubium spurrelli (Agalychnis) Roulenger, 1913 Agalychnis spurrelli stadelmani ( Hyla ) Schmidt, 1936 Hyla loquax staufferi (Hyla) Cope, 1865 Hylastaufferistaufferi subocularis (Hyla) Dunn, 1934 Hyla subocuhris sumichrasti (Exerodonta) Rrocchi, 1879 Hyla sumichrasti taeniopus (Hyla) Gunther, 1901 _. _ Hyla taeniopus taylori (Phyllomedusa callidryas) Funkhouser, 1957 Agalychnis callidry as thorectes (Hyla) Adler, 1965 ~~ Hyla thorectes thysanota ( Hyla ) Duellman, 1966 Hyla thysanota tica (Hyla) Starrett, 1966 Hylatica underwoodi (Hyla) Roulenger, 1899 Hyla microcephala underwoodi uranochroa (Hyla) Cope, 1876 Hyla uranochroa valancifer (Hyla) Firschein and Smith, 1955 Hyla valancifer vanvlietii (Hyla) Raird, 1854 Smilisca baudinii venulosa (Rana) Laurenti, 1768 _ Phrynohyas venulosa venusta (Phyllomedusa) Duellman and Trueb, 1967 Phyllomedusa venusta vermiculata (Hyla) Dumeril and Ribron, 1841 Phrynohyas venulosa vociferans (Hyla) Raird, 1859 Smilisca baudinii walked (Hyla) Stuart, 1954 Hylawalkeri wellmanorum (Hyla) Taylor, 1952 Smilisca puma weyerae ( Hyla ) Taylor, 1954 __ Hyla ebraccata wrightorum ( Hyla ) Taylor, 1939 __ ._.. Hyla eximia xanthosticta (Hyla) Duellman, 1968 Hylaxanthosticta zeteki (Hyla) Gaige, 1929 __ Hylazeteki zonata (Hyla) Spix, 1824 _ Phrynohyas venulosa I collected at Chinaja and Toocog in the De- companied by a group of graduate students partamento El Peten, Guatemala. John Well- to Mexico; we worked briefly in the Sierra man and I returned there in June 1960, and Madre Oriental and then spent two months then spent July concentrating our efforts on in the Yucatan Peninsula, where we were Plectrohyla and Ptychohyla in the Guate- fortunate to find Triprion petasatus in abun- malan highlands. In August we were joined dance. by Dale L. Hoyt and spent a month working The summer of 1963 was spent in Panama, in the mountains of Chiapas and Oaxaca in accompanied by Charles W. Myers. Studies Mexico. on hylids were made at Rarro Colorado Is- In February, 1961, Jerome R. Tulecke and land and at Achiote on the Caribbean low- I collected briefly in Guatemala, Honduras, lands of Colon Province. Excellent collections and on Cerro Montecristo in El Salvador, be- were obtained at El Valle, on Cerro La Cam- fore setting up headquarters in San Jose, pana, at Volcan and Roquete in Chiriqui Costa Rica. We spent five months gathering Province, and in the savanna country near data on Costa Rican hylids and were joined Chepo. Through the cooperation of the Gor- in June by Craig E. Nelson. In July and gas Memorial Laboratory in Panama, we August, 1961, the three of us worked slowly were able to accompany an expedition to the northward through Central America and Serrania del Darien on the Colombian border; Mexico. In the summer of 1962, I was ac- there we obtained much valuable material. 1970 DUELLMAN: HYLID FROGS 17 In January, 1964, Charles J. Cole and I ar- rived in Panama to join Alexander Wetmore and Charles O. Handley, Jr. in another expe- dition to the Serrania del Darien; our princi- pal objective was Cerro Tacarcuna, the high- est mountain in eastern Panama. The Canal Zone "crisis" disrupted our plans and resulted in our working briefly on Barro Colorado Is- land and in the Altos de Pacora. The ridges leading to the top of Cerro Tacarcuna still remain untrodden by a herpetologist. In June of 1964, I again went to Mexico accompanied by a group of graduate students. We worked in the Sierra Madre del Sur in Guerrero and Oaxaca and in the Sierra de Juarez in northern Oaxaca. In early July, I worked briefly in Nicaragua with a field party from the University of Kansas; three of the members of the party — Charles J. Cole, Lau- rence M. Hardy, and Richard L. Holland — spent most of the summer working in Nica- ragua. I went on to Costa Rica and joined Linda Trueb; we collected out of San Isidro el General and Puerto Viejo. Cole and Hol- land joined us in late August and made col- lections at Tilaran and Pandora. In July, 1964, Charles W. Myers initiated three years of field work in Panama. During the tenure of his stay in Panama, he sampled the herpetofauna of every part of the country. In February and March, 1965, I joined him for field work in the Bocas Archipelago and in the mountains of Chiriqui. In the summer of 1965, Linda Trueb and I joined Myers for a month in the upper Tuira Basin in Darien, where we discovered Agalychnis litodryas and Phylhmedusa venusta. In August of the same year, Trueb and I obtained some hylid ma- terial from the Golfo Dulce region in Costa Rica. In early 1966, field work was planned for concentrated effort in areas that were poorly known and to acquire needed recordings and data on life histories. Linda Trueb and I de- parted in a camper for Middle America in early February, 1966. We spent a week in the cloud forests of eastern Mexico and then worked for a week in the Sierra Madre del Sur in Oaxaca, where we discovered Hijla altipotens and pellita. In the highlands of Chiapas, we were unsuccessful in obtaining the rare Plectrohyla pycnochila, so we con- tinued into Guatemala and crossed to the north slopes of the Sierra de Cuchumatanes only to be disappointed in finding most of the area heavily cut over and nothing of interest in hylid frogs. As guests of the Escuela Agri cola Panamericana in El Zamorano, Hon- duras, we spent four unsuccessful days in the cloud forest on Cerro Uyuca. By late March, we were in Costa Rica, where we obtained valuable data at Tapanti, Cinchona, and on the south slope of Cerro de la Muerte. In five days on Volcan Barba, we managed to obtain tadpoles, juveniles, adults, and recordings of the mating call of the rare Hyla angustiline- ata. Late in April of 1966, we joined Charles W. Myers for a five-week trip from Santa Clara, Chiriqui Province, Panama, over Cerro Pando, and down to the Rio Changena in Bocas del Toro Province. At each of our four camps, we obtained excellent collections of, and a wealth of data on, hylid frogs. Part of June was spent on the Panamanian savannas and in the Azuero Peninsula before returning to Costa Rica, where, accompanied by Juan R. Leon and John D. Lynch, we again visited Volcan Barba and Cinchona and spent a profitable four days at Puerto Viejo. Early in July, we met Arthur C. Echternacht in Mana- gua, Nicaragua, and worked briefly in the Sebaco-Matagalpa area before going on to Honduras for a successful assault on Cerro Uyuca for Hyla salvadorensis. A brief stay in Guatemala was made memorable by missing a topotypic Plectrohyla avia. The first half of August was spent in Oaxaca, where valuable data were obtained in the Sierra Madre del Sur, in the Sierra de Juarez, and on Cerro San Felipe. In the latter part of August, we worked northward through western Mexico. Thus, upon crossing the Rio Grande on Au- gust 26, 1966, I completed my field work on Middle American hylids, which had begun 15 years before and had amounted to nearly four years in the field. CLASSIFICATION AND IDENTIFICATION CLASSIFICATION OF THE HYLIDAE Approximately 450 species are recognized in the family Hylidae. The variety of morpho- logical, developmental, and behavioral traits of this vast array of species creates some in- triguing problems of classification. Two-thirds of the recognized species are currently placed in the genus HyJa, which most likely is com- posite. This genus presently contains such widely divergent Neotropical species as mi- liaria and nana and Australian species as caerulea and ewingi. In addition to the genus Hyla, the other 150 species are placed in 31 genera, some of which are only weakly differ- entiated from some species groups of Hyla, whereas others possess distinctive combina- tions of characters. Obviously, until a thor- ough study has been made on the morphology and life histories of at least representatives of all of the genera and of the species groups in Hyla, any classification of the hylicl frogs is likely to be tenuous. Nevertheless, I am pre- senting here a tentative classification of the Hylidae with the full realization that many parts of it will not withstand the test of time. Although this classification has many weak- nesses, I think it is more realistic than pre- vious ones. Some of the evidence for the classification, together with some of its in- herent problems are discussed following its presentation. Family Hylidae Hallowell Hylidae Hallowell, 1857, p. 237. Frogs having procoelous vertebrae, a dou- ble coccygeal condyle, arciferal pectoral gir- dle, disc-shaped intercalary cartilages be- tween terminal and penultimate phalanges, and usually claw-shaped terminal phalanges. Subfamily Phyllomedusinae Giinther Phyllomedusidae Giinther, 1859, p. 120. Phyllomedusinae Miranda-Ribeiro, 1926, p. 100. Frogs having moderately ossified skulls, with or without the dermis co-ossified with the skull; pupil vertical; aquatic tadpoles. Three genera. Agalyclmis Cope, 1864, p. 181. Eight spe- cies in Middle America and northwestern South America. Pachymedusa Duellman, 1968b, p. 5. One species in western Mexico. Phyllomediisa Wagler, 1830, p. 201. Thirty- one species in tropical America. Subfamily Hemiphractinae Gadow Hemiphractinae Gadow, 1901, p. 210. Frogs having a triangular helmet but with- out dermis co-ossified with the skull; ptery- goids and palatines massive, the latter bear- ing teeth; pupil horizontal; young developing directly from eggs carried on the back of female. One genus. Genus Hemiphractus Wagler, 1830, p. 743. Five species in northwestern South America and lower Central America. Subfamily Amphignathodontinae Boulenger Amphignathodontidae Boulenger, 1882a, p. 449. Amphignathodontinae Gadow, 1901, p. 139. Frogs having extensively ossified skulls, with or without the dermis co-ossified with the skull; pupil horizontal; eggs carried on back or in dorsal pouch of females (except Anotheca and Nyctimantis). Eight genera. Amphignathodon Boulenger, 1882a, p. 450. One species in Ecuador. Anotheca Smith, 1939, p. 190. One species in Middle America. Cryptobatrachus Ruthven, 1916, p. 1. Two species in the highlands of Colombia. Flectonotus Miranda-Ribeiro, 1920b, p. 321. One species in southeastern Brasil and one in Venezuela. Fritziana Mello Leitao, 1937, p. 330. Two species in southeastern Brasil. Gastrotheca Fitzinger, 1843, p. 30. Nine- teen species in southeastern Brasil and the Andes of Bolivia northward into lower Cen- tral America. Nyctimantis Boulenger, 1882a, p. 421. One species in Amazonian Ecuador. 18 1970 Stefania Rivero, 1967, p. 142. Four species in the Guiana highlands of Venezuela and Guyana. Subfamily Hylinae Gray Hylina Gray, 1S25, p. 213. Hylinae Gadow, 1901, p. 139. Frogs having variable cranial conditions; pupil horizontal, except in Nyctimystes; aquatic tadpoles. Twenty genera. Acris Dumeril and Bibron, 1841, p. 506. Two species in eastern and central North America. Allophryne Gaige, 1926, p. 1. One species in northeastern South America. Aparasphenodon Miranda-Ribeiro, 1920a, p. 87. Two species in southeastern Brasil and Orinoco Basin in Venezuela. Aplastodiscus Lutz, 1950a, p. 612. One species in southeastern Brasil. Argenteolujla Trueb, 1970b, p. 255. One species in Uruguay and northern Argentina. Corythomantis Boulenger, 1896, p. 405. One species in northeastern Brasil. Hyla Laurenti, 1768, p. 32. At least 300 species in all temperate and tropical parts of the world, except Africa from the Sahara southward and the islands in the Pacific Ocean. Limnaoedus Mittleman and List, 1953, p. 83. One species in southeastern United States. Nyctimystes Stejneger, 1916, p. 85. Twen- ty species in New Guinea and northern Aus- tralia. Osteocephalus Steindachner, 1862, p. 77. Five species in Amazonian South America. Phnjnohyas Fitzinger, 1843, p. 30. Six species in tropical America. PhyUodytes Wagler, 1830, p. 202. Three species in eastern Brasil and one on Trinidad. Plectrohyla Brocchi, 1877a, p. 93. Ten species in the highlands of northern Central America. Pseudacris Fitzinger, 1843, p. 31. Seven species in North America east of the Rocky Mountains. Ptemohyla Boulenger, 1882b, p. 326. Two species in western Mexico. Ptychohijla Taylor, 1944a, p. 41. Five spe- cies in the highlands of southern Mexico and northern Central America. Smilisca Cope, 1865b, p. 194. Six species DUELLMAN: HYLID FROGS 19 in Middle America and northwestern South America. Sphaenorhynchus Tschudi, 1838, p. 71. Seven species in tropical South America east of the Andes. Trachycephalus Tschudi, 1838, p. 74. Three species in eastern South America and Pacific lowlands of Ecuador and Colombia. Triprion Cope, 1866a, p. 127. Two species in western Mexico and Yucatan Peninsula. The arrangement given here differs from Goin's ( 1961b ) synopsis of hylid genera by the addition of four genera (Stefania Rivero, 1967, Pachymedusa Duellman, 1968b, Argen- teohyla Trueb, 1970b, and Limnaoedus Mit- tleman and List, 1953; the latter was placed as a synonym of Hyla by Goin 1961b) and the deletion of six genera. Trueb (1970a) synonymized Diaglena with Triprion and Tetraprion with Trachycephalus. Bokermann (1966b) treated Nototheca as a synonym of Flcctonotus; Habrahyla Goin (1961a) is a synonym of the rhacophorid Leptopelis Giin- ther, 1859 ( Mertens, 1963 ) . Cerathyla is sy- nonymized with Hemiphractus in this paper, and Hyloscirtus is synonymized with Hyla. Bokermann (1966a) showed that PhyUodytes Wagler, 1830, is an earlier name for Ampho- dus Peters, 1872. The subfamilial arrangement given here is based on seemingly minor morphological char- acters and on life history. The status of the Neotropical genera in the Phyllomedusinae was discussed by Duellman ( 1968b ) , who gave considerable weight to the presence of a vertical pupil in those genera. In the ad- vanced families of frogs, vertical pupils occur sporadically in some African ranids and rha- cophorids and consistently in the phyllome- dusine hylids and some primitive Australian leptodactylids. Triprion and Nyctimantis have horizontal pupils; some earlier workers reported vertical pupils in those genera. Lynch (1969) considered the condition of the pupil in leptodactylids as an indication of relationships with the megophryine peloba- tids. All of the phyllomedusine genera have a differentiation of an anterior slip of the sub- maxillaris muscle, a condition so far known to occur only in some of the Australian spe- cies currently placed in the genus Hyla. Cei 20 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 (1963) and Cei and Erspamer (1966) noted the distinctive biochemical properties of the skin in Neotropical phyllomedusines; the re- sults of their current researches on some of the Australo-Papuan hylids should be interest- ing with regard to the relationships of Nyc- timystes to the American genera. With the exception of Anotheca and Nyc- timantis, in all of the amphignathodontine genera the females carry the eggs on their backs (Cryptobatrachus, Fritziana, and Ste- fania) or in a dorsal pouch ( Amphignatho- don, Flectonotus, and Gastrotheca) . The re- lationships of these genera are indicated by the nature of the brooding habits and varying stages of the development of a brood pouch from the simple adherence of eggs on the back in Stefania to the individual depressions for eggs in Cryptobatrachus and a single large basin with individual depressions in Fritziana. A slit-like dorsal pouch is present in Flecto- notus; only the posterior end of the slit is open as a puckered aperture in Gastrotheca, and Amphignathodon. These two genera seem to be closely related and perhaps should be placed in one genus. Amphignathodon differs from all other hylids by having teeth on the dentary. Nothing is known about the life his- tory of Nyctimantis. Anotheca differs from all other amphignathodontine genera by hav- ing much less specialized breeding habits; the eggs are deposited and the tadpoles develop in arboreal bromeliads or water-filled cavities in trees. However, on the bases of general cranial characters and features of external morphology, Anotheca closely resembles the casque-headed species of Gastrotheca. Thus, mindful that these similarities may be the result of convergence, I tentatively place Anotheca in the Amphignathodontinae rather than the Hylinae. Hemiphractus is a morphological oddity. The peculiar skull is mostly due to modifica- tions of the dermal roofing bones. The pres- ence of odontoids on the prevomers and den- taries is unique among hylids. The eggs are carried in separate depressions on the backs of females and hatch into frogs. Despite the similarities in brooding and development, I consider the morphological modifications to be of sufficient magnitude to set Hemiphrac- tus apart as a separate subfamily from the Amphignathodontinae. The remaining 19 genera are placed in the Hylinae. Although there is excellent evi- dence in support of relationships among some groups of genera in the subfamily, there is little evidence of relationships between some other genera. Thus, the Hylinae is composed of all those genera that cannot be relegated to some other subfamily. The greatest need for research is with the frogs in this subfamily. I have not recognized the subfamily Tri- prioninae Miranda-Ribeiro, 1926; Trueb ( 1970a ) showed that the casque-headed gen- era assigned to this subfamily represent at least three phyletic lines from Hi/la. Thus, Smilisca, Pternohyla, and Triprion are closely related, and Phrynohyas, Argenteohijla, Os- teoceplialus, and Trachycephalus represent a single phyletic line (Trueb, 1970b). Cory- thomantis and Aparasphenodon apparently have diverged from a Hyla rubra group stock. Acris, Lirnnaoedus, and Pseudacris seem to form a closely related group of genera in North America. Plectrohyla and Ptychohyla are independently derived groups from Mid- dle American Hyla. Sphaenorhynclnis and Phyllodytes apparently are South American de- rivatives of Hyla. The status of the monotypic South American Aplastodiscus and Allo- phryne is questionable. Lynch and Freeman ( 1966 ) noted the T-shaped terminal pha- langes and absence of teeth in Allophryne and tentatively referred Allophryne ruthveni to the Hylidae. The clues to the relationships of many of the genera of hyline frogs are hidden in the complexities of the immense genus Hyla. Obviously, the frogs currently placed in this genus have undergone a tremendous adaptive radiation, which through divergence, con- vergence, and parallelism has resulted in an obfuscation of relationships. A major prob- lem is the possible polyphyletic nature of the genus Hyla as now recognized. The simi- larities in vertebral characters and the identi- cal number of chromosomes in some of the Australian Hyla with Nyctimystes and the Neotropical phyllomedusines perhaps is evi- dence for closer relationships of those Aus- tralian Hyla with the phyllomedusines than with the bylines. I have few illusions to the permanence of these ideas. My intention in presenting the classification and the feeble amount of evi- 1970 DUELLMAN: HYLID FROGS 21 dence in support of the arrangement has not been to provide a fixed classification but rather to stimulate the search for new evi- dence so that in the future a realistic classi- fication of hylid frogs will be based on an amalgamation of morphological, develop- mental, behavioral, biochemical, and cyto- genetic evidence. TAXONOMIC CHARACTERS AND CRITERIA IN HYLID FROGS Proper assessment of the morphological and behavioral traits of the Middle American hylid frogs is dependent upon an understand- ing of the kinds of characters and the nature of the variation in these characters. Each of the characters used in the taxonomic study of the Middle American hylids is defined and discussed in the following paragraphs. Adap- tive significance, evolutionary trends, and re- lationships between morphological characters and environmental conditions are excluded here. They are presented in the later discus- sions of relationships and distribution. External Morphology Among the herpetological forms of life, frogs are notorious for their lack of definitive external characters. The absence of scales, costal grooves, or other countable characters is faced by most workers with mixed feelings. To someone like myself, who counted tens of thousands of scales on Leptodeira and spent countless hours peering through a microscope while counting the granules on Cnemidoph- orus, the absence of such taxonomically im- portant structures in frogs is a great blessing. Although there are some definite "present or absent" external characters in hylids, most of the differences are relative. During a visit to the Academy of Natural Sciences of Phila- delphia many years ago, I handed the late Em- mett R. Dunn two hylids that he had identi- fied as different species and asked him how he distinguished one from the other. He carefully compared them for a minute and then boldly announced: "They look different. That's how." Upon close examination I, too, could see that they looked different. Perhaps some of my readers will feel that in the ac- counts of the species I have unduly belabored certain aspects of the descriptions of external characters. However, I am merely trying to relate what the frogs look like. Measurements and Proportions Seven measurements were routinely made (fig. 2): snout-vent length — direct line dis- tance from the tip of the snout (excluding a fleshy proboscis, if present) to the posterior margin of the vent; tibia length — straight length of the tibia; foot length — distance from the proximal edge of the inner metatarsal tubercle ( the large tubercle at the base of the first toe ) to the tip of the longest ( fourth ) toe, including disc; head length — straight line dis- tance from the posterior edge of the jaw articulation to the tip of the snout; head width — the greatest width of the head, usu- ally at about the level of the anterior edges of the tympani; diameter of the eye — greatest length of the orbit; diameter of the tympanum — greatest horizontal distance between the outer edges of the tympanic ring. Four other measurements were taken on some species: interorbital distance — the width of the fronto- parietals between the orbits; width of eyelid ■Snout-Vent Fig. merits. 2. A hylid frog showing places of measure- 22 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 — greatest width of the upper eyelid; inter- narial distance — the distance between the me- dian margins of the external nares; snout length — the straight line distance between the anterior corner of the orbital opening and the posterior margin of the external nares. Measurements of preserved frogs have limited values. Recause it can be assumed that frogs continue to grow throughout life and have slight changes in proportions dur- ing growth, even after sexual maturity, the usefulness of measurements, except for snout-vent length in adults, is of much less taxonomic value than in endotherms. Recause of continued growth, proportions rather than actual measurements, are better for making comparisons between samples and species. On all specimens four ratios to snout-vent length were calculated: tibia length, foot length, head length, and head width. In those species having distinct tympani, the ratio of the diameter of the tympanum to that of the eye was calculated. The interorbital distance, internarial distance, and width of the eyelid are expressed as ratios of the head width, and the snout length is expressed as a ratio of the head length or the diameter of the tympanum. The size of Middle American hylids varies from that of Hyla picta, in which males reach a known maximum snout-vent length of 21.4 mm., to the gigantic Hyla boans, in which males attain a maximum snout-vent length of 131.9 mm. Other very small species of Hyla and the maximum snout-vent lengths of males are: subocularis (23.1 mm.), zeteki (23.5 mm.), and phlebodes (23.6 mm.). The very large species in which the maximum snout- vent length exceeds 100 mm. in males, besides Hyla boans, are Hyla miliaria (106.0 mm.) and Phrynohyas venulosa (100.5 mm.). The Hispaniolan Hyla vasta is usually considered to be the largest hylid frog; Cochran ( 1941, p. 21) reported a female of that species with a snout-vent length of 142 mm., but her larg- est male had a snout-vent length of 112 mm., considerably smaller than the largest Pana- manian Hyla boans and even smaller than the average snout-vent length of 119.9 mm. in ten Hyla boans from Sasardi Panama. Thus, it is likely that Hyla boans is the largest spe- cies in the family. In general terms, I have referred to species in which the males have snout-vent lengths of 30 mm. or less as being small, 30 to 50 mm. as medium-sized, 50 to 80 mm. as large, and more than 80 mm. as very large. Usually the members of a given species group are in the same size-class. For example, all members of the Hyla microcephala group are small, and all members of the Hyla taeniopas group are large. For the most part, closely related spe- cies are similar in size. The general habitus or shape of the body is difficult to measure and is expressed in general terms. Most hylids, except gravid fe- males, are rather slender frogs. There are two major exceptions — the squat toad-like body of Pternohyla and the depressed body of Hcmiphractus. Head The head is generalized in most species, but it is modified in some in which the cranial roofing bones are expanded and frequently co-ossified with the skin ( see discussion of dermal modification in section on Cranial Osteology). The development of broad la- bial flanges and cranial crests results in a highly modified head in Pternohyla and Tri- prion. The head of Anotheca is modified by the presence of numerous spines arising from the dermal cranial bones, and that of Hemi- phractus is arrow-shaped due to the postero- lateral expansion of the squamosals. The shape of the snout is a reliable and easily discernible taxonomic feature. In dor- sal view, the snout is truncate, round, or acuminate; these same shapes are evident in lateral views, but laterally, the snouts of some species are sloping or acuminate and protruding beyond the margin of the lower jaw, such as in Hyla boalengeri (fig. 3). In Hyla chryses and siopela, Ptychohyla leon- hardschultzei and spinipollex, and Plectrohyla ixil and matudai, a fleshy vertical rostral keel is present ( fig. 4G and H ) . This keel is readily apparent in most individuals of those species, except specimens that are soft and have been standing on their noses in jars for a number of years. In all juveniles and in most adults of Hcmiphractus panamensis, a fleshy triangu- lar proboscis is present on the tip of the snout (fig. 41). The only other dermal appendage 1970 DUELLMAN: HYLID FROGS 23 on the head is the fleshy supraorbital "horn" that is well developed in Gastrotheca cera- toplirys and less so in Hemiphractus pana- mensis (fig. 41 and J). Three characters on the anterior part of the head are highly subjective; these are the canthus ( canthus rostralis ) , loreal region, and the lips. The canthus is the angle of the head from the anterior corner of the eye to the nostrils or to the tip of the snout. The con- dition of the canthus varies: indistinct and rounded, distinct and rounded, angular, acutely angular, and elevated and ridge-like. The loreal region is the side of the face be- tween the canthus and the lips. The condi- tion of the loreal region is a reflection of the nature of the canthus and the lips. In most hylids, the loreal region is slightly concave; in a few species it is nearly flat and inclined laterally, and in species with prominent can- thai ridges and flared lips, the loreal region is deeply concave. The nature of the lips is most easily determined in an anterior view. In those hylids having robust, but generalized, heads the lips tend to be massive (thick) and barely, if at all, flared laterally. Those species having depressed heads tend to have thin and flared lips. The lateral flaring is most pro- nounced in the species of Triprion, which have broad labial flanges. The nature of these three facial features is primarily dependent upon the structure of the underlying nasal and pars facialis of the maxillary. The pupil of the eye is horizontally ellip- tical in all Middle American hylids, except the phyllomedusine genera Agahjchnis, Pa- chymedusa, and PhyUomechisa, in which it is vertically elliptical (fig. 5). The palpebral membrane, the transparent lower eyelid, is unpigmented or only barely pigmented in most species. However, in Hijla boans, Pa- chymedusa dacnicohr, and all species of Agahjchnis (except calcarifer), the membrane has a pigmented reticulation (fig. 5). A dermal fold, the supratympanic fold, extends posteriorly from the corner of the eye. This fold passes just above the tym- panum and continues onto the flank, slopes downward to a point above the insertion of < Fig. 3. Lateral views of heads of hylid frogs show- ing shapes of snouts. A. Truncate. B. Round. C. Sloping. D. Acuminate. E. Protruding. 24 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 the arm, or angles ventrally to the angle of the jaw. In most species, the fold obscures the upper edge of the tympanum, and in some of those in which the fold drops to the angle of the jaw, the posterior edge of the tym- panum also is covered. In most of the small species and most pond-breeding hylids the supratympanic fold is comparatively thin, whereas it is much heavier in some of the larger stream-breeding frogs of the Hyla bistincta and taeniopus groups and in those of the genus Plectrohyla. In these frogs, the tympanum in some individuals is nearly hid- den beneath the supratympanic fold. The same condition exists in some specimens of Phrynohijas (see discussion of parotoid glands in the section on skin). A tympanum and usually a tympanic ring are evident in most Middle American hylids. The tympanum is barely evident and the tympanic ring absent in Hyla melanomma, picadoi, and zeteki. The tympanum is completely concealed beneath the skin in Plectrohyla lacertosa, Hyla pachy- derma, Hyla pinorum, and the four species in the Hyla mixomaculata group. With the ex- ception of Hyla picadoi and zeteki, which breed in bromeliads, all species in which the tympanum is indistinct or concealed are stream breeders. The tongue in hylids is not extensible; it is usually barely free behind and free for no more than half of its length. The shape of the tongue is of some taxonomic importance; however, the shape is dependent upon careful Fig. 5. Eyes of hylid frogs. A. Vertical pupil and reticulated palpebral membrane. B. Horizontal pupil and unpigmented palpebral membrane. <- Fig. 4. External morphological characters of hylid frogs. Arrows indicate important structures. A. Foot showing dermal fringe. B. Foot showing calcar. C. Foot of Pternohijla jodiens showing spatulate inner metatarsal tubercle and tarsal fold. D. Foot of Hyla elaeochroa showing reduced webbing between first and second toes characteristic of the Hyla rubra group. E. Axillary membrane. F. Thoracic fold. G and H. Rostral keel. I. Fleshy proboscis on Hemiphractus panamensis. J. Supraocular fleshy "horn" on Gastro- theca ceratophrys. 1970 DUELLMAN: HYLID FROGS 25 and uniform preparation. Four shapes are recognized in Middle American hylids: round, cordiform (heart-shaped), elongately ovoid, and lanceolate (fig. 6). The vocal slits are paired — one on either side of the floor of the mouth. The slit usually extends from the midlateral base of the tongue nearly to the angle of the jaw; in some groups, the slit lies along the median edge of the mandible. Fig. 6. Tongues of hylid frogs. A. Round. B. Cordiform. C. Ovoid. D. Lanceolate. The vocal sacs of Middle American hylids are of four structural types ( fig. 7 ) . The most common type is the single median subgular sac; in Hyla pseudopuma, the sac is weakly constricted medially and is termed a bilobate subgular sac. In Triprion petasatus and all species of Smilisca and Pternohyla the vocal sac forms two bulbous protrusions with a deep medial constriction between; this type is called the paired subgular vocal sac. In Phrynohyas, the vocal sacs are paired and behind the angles of the jaws. The vocal sacs in all of these frogs are formed by modifica- tion of the thin submaxillaris ( intermandibu- laris) muscle. The submaxillaris is attached medially by fascia to the deeper hyoglossus and geniohyoideus muscles in those species having paired subgular vocal sacs. The paired lateral sacs in Phrynohyas are formed by pos- terolateral extensions of the submaxillaris ( see Duellman, 1956a, for detailed description). The single, median subgular vocal sacs in most of the pond-breeding frogs are greatly distensible, whereas in many of the stream- breeding species, the sacs are only moderately or barely distensible. Vocal slits, vocal sac, and presumably a voice are lacking in Hyla altipotens, the Hyla bistincta group (except bistincta and pentheter), the Hyla mixomacu- lata group, the large species of Plectrohyla, and in some populations of Hyla chaneque. Fig. 7. Structural types of vocal sacs. A. Single, median, subgular. B. Bilobate subgular. C. Paired subgular. D. Paired lateral. Skin The nature of the skin, its structure and modifications in such places as around the anal opening, the presence of dermal ap- pendages, and the kinds and positions of glands, are of considerable taxonomic im- portance. It must be noted however that the nature of the dermal features is strongly af- fected by preservation. Generally in speci- mens that are soft and poorly preserved or in those that were slightly decomposed prior to preservation, rugosities, folds, and tubercles are minimized, whereas in specimens that have been desiccated or preserved in very 26 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 strong formalin, those structures are empha- sized. In general, the skin on the dorsum of most hylids is smooth; that on the ventral sur- faces of the arms and shanks is smooth and that on the throat, chest, belly, and ventral surfaces of the thighs is granular. The gran- ules are not apparent in the skin of distended vocal sacs. The skin on the dorsum in several species of Hyla and some of Plectrolujla is weakly tuberculate and that in Phnjnohyas is strongly tuberculate. In the populations of Hyla lancasteri at high elevations, the tuber- cles are elongated into fleshy "spines." In some species in the Hyla bistincta, parviceps, rividaris, and taeniopus groups, a thoracic fold (fig. 4F) is present. This should not be confused with the transverse dermal fold formed by the deflated vocal sac in breeding males. A web of skin, an axillary membrane (fig. 4E), extends from the flank to the posterior edge of the forearm. This membrane extends nearly to the elbow in members of the Hyla godmani and swni- chrasti groups and is less extensive but pres- ent in all members of the bromeliacia, ery- thromma, microcephala, mixomaculata, picta, and rivularis groups of Hyla. An axillary membrane is present in the three small mem- bers of the Hyla rubra group and in some members of the Hyla bistincta group. A row of tubercles is present on the ven- trolateral edge of the forearm in many spe- cies; these are most prominent in some of the larger stream-breeding frogs, such as mem- bers of the Hyla bistincta and taeniopus groups In most Middle American hylids, a transverse dermal fold is present on the dor- sal surface of the wrist and the outer surface of the heel. Members of the Hyla miliaria group have a scalloped dermal fringe along the outer edges of the forearms, hands, and feet (fig. 4A); these are the so-called fringe- limbed hylids. A prominent triangular dermal flap or calcar is present on the heel in Aga- lychnis calcarifer, Gastrotheca ceratophrys, Hemiphractus panamensis, and Hyla boans (fig. 4B). The position of the anal opening and its attendant folds and tubercles show various modifications in Middle American hylids. In most of the small pond-breeding frogs, the anal opening is directed posteriorly at the up- per level of the thighs and is covered by a short, broad anal flap (fig. 8A). In some pond-breeders and many stream-breeding hylids, the anal opening is directed postero- ventrally at the midlevel of the thighs and covered by a moderately long anal sheath ( fig. 8B ) . The anal opening is directed ven- trally near the ventral surfaces of the thighs and covered by an elongate anal sheath in some Agalychnis, Pachymedusa clacnicolor, and some members of the Hyla bistincta and taeniopus groups (fig. 8C). The only dorsal aperture is the brood pouch in females of Gastrotheca. Females of Hemiphractus that are carrying eggs or young have depressions in the dorsal skin; the eggs and at later stages, the young are attached to the skin in these depressions (pi. 7). The skin in hylids contains numerous mucous glands and fewer poison glands; the latter apparently are modified mucous glands. Poison glands are concentrated in the exten- sive parotoid glands in Phnjnohyas, in which the skin is thickened and glandular on the head and neck. McDiarmid (1968, p. 20) demonstrated that the parotoid glands are better developed in specimens obtained in Fig. 8. Posterior and sectional views of anal open- ings. A. Directed posteriorly at upper level of thighs. B. Directed posteroventrally at midlevel of thighs. C. Directed ventrally at lower level of thighs. 1970 DUELLMAN: HYLID FROGS 27 the dry season than in those collected in the rainy season. Because of the slime secretion by these frogs and the effectiveness of the slime in preventing desiccation, McDiarmid suggested that "the greater development and subsequent secretion of the glands in the dry season is produced as an adaptive re- sponse to arid environments." Long, ele- vated dorsolateral parotoid glands are present in Phyllomcdusa venusta. Breeding males of the genus Ptychohyla have thickened, pigmented ventrolateral glands on the body (fig. 9A). The glandular areas seem to be composed of large concen- trations of mucous glands. Because the glands are present only in breeding males, it is sur- mised that the glands are associated with some phase of the breeding activity. Adults of both sexes of HyJa colymba have an ovoid "mental gland" on the chin (fig. 9B); the histological structure and function of the gland is unknown. Osteoderms are present in the dorsal skin of Hyla miliaria and PhyUomedusa venusta. Possibly these result in a decrease in the permeability of the skin and help to reduce desiccation in these arboreal frogs. The tips of granules on the chest in some specimens of Smilisca phaeota and on various parts of Fig. 9. Glands on ventral surfaces. A. Ventro- lateral glands of Pttjcholnjla. B. Mental gland of Hyla colymba. the venter in large specimens of Hyla miliaria are keratinized. The significance of keratini- zation of the granules is unknown. Hands and Feet The structural characters of the hands and feet are of immense taxonomic importance and are easily studied on specimens that have been fixed in trays with their hands and feet spread and the digits straight. The terminol- ogy of the structures of the hands and feet is as follows: Digit: any one of the four fingers or five toes. Phalanx: any one of the bony segments of a given digit; the terminal phalanx (disc) is offset ventrally and separated from the proximally adjacent phalanx by an intercalary cartilage. Disc: the terminal phalanx; it is expanded and flattened in most species. Penultimate phalanx: the phalanx immedi- ately proximal to the disc. Antepenultimate phalanx: the phalanx im- mediately proximal to the penultimate pha- lanx. Thumb: the first (inner) digit on the hand. Prepollex: the vestigial digit on the inner base of the thumb. Prepollical spine: the bone supporting the prepollex and protruding through the distal end of the prepollex in some species. Nuptial excrescence: the horny pad or keratinized area on the inner surface of the prepollex (also on other digits in some spe- cies) in breeding males. Subarticular tubercles: those tubercles be- low the articulations of the phalanges. Supernumerary tubercles: the small tu- bercles on the ventral surfaces of the digits, exclusive of the larger subarticular tubercles; absent in some hylids. Palmer tubercle: one or more tubercles on the palm at the bases of the third and fourth fingers. Inner metatarsal tubercle: the large tu- bercle on the ventral surface of the foot at the base of the first (shortest) toe (fig. 4C). Outer metatarsal tubercle: a small tubercle on the ventral surface of the foot at the base of the fourth (longest) toe; absent in many species. 28 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Tarsal fold: a dermal fold on the ventral surface of the foot commencing at the heel or distal thereto and terminating at the inner metatarsal tubercle (fig. 4C). Outer tarsal fold: a weak dermal fold on the outer edge of the foot in some populations of Ptijchohyla glanduhsa. Web: the membraneous skin connecting the fingers and the toes. The relative lengths of the digits, from shortest to longest, are on the hand 1-2-4-3 and on the foot, 1-2-5-3-4. The relative lengths of the fingers differs in Hemiphractus and Qastrotheca; in those genera the first finger (thumb) is longer than the second. In Phyl- lomedusa venusta the first toe is longer than, and opposable to, the second. The fingers are proportionately longer in Gastrotheca, Anotheca, Hemiphractus, and the stream- breeding frogs of the Hijla bistincta, lan- casteri, and pictipes groups and Plectrolujla. The fingers are proportionately shorter in many of the pond-breeding frogs, such as Agalychnis and members of the Hijla god- mani, leucophyllata, microcephala, and picta groups. Short fingers are characteristic of the bromeliad-breeding members of the Hijla bromeliacia group and the stream-breeding Hijla sumichrasti group. The terminal discs on the fingers are usually larger than those on the toes. The discs are round, or nearly so, in all species except Hijla boulengeri and rostrata, in which they are truncate. The terminal phalanges are not expanded in Acris, Hemiphractus, Pternohyla, and Phijllomedusa venusta and barely expanded in Pseudacris and members of the Hijla eximia group. In most of the large arboreal hylids, the discs are proportionately very large, such as in Aga- lychnis, Anotheca, Gastrotheca, Phrynohijas, and members of the Hijla albomarginata, boons, and miliaria groups. Large discs are also present in the three largest species of Plectrolujla (avia, guatemalensis, and hart- wegi). The subarticular tubercles vary in size and structure. They are largest in some of the large arboreal groups, such as Agalychnis, Gastrotheca, Phrynohijas, and the Hyla albo- marginata, boons, and miliaria groups. The subarticular tubercles also are large in the terrestrial Pternohyla and the stream-breeding Plectrolujla and members of the Hyla bis- tincta and taeniopus groups. The subarticular tubercles usually are round or subconical, but in many species, the distal tubercle on the fourth finger (and in some individuals, the distal tubercle on the third finger) is bifid or even divided (fig. 10). Rifid subarticular tubercles are characteristic of such diverse groups as Phrynohijas, Plectrolujla, Ptycho- lujla, Hemiphractus, and in the Hyla leuco- phyllata, microcephala, and rividaris groups; bifid tubercles occur in many other groups. Recause of the variability of the distal sub- articular tubercle on the fourth finger, I do not consider the bifid versus entire tubercle to be of much taxonomic importance. The shape of the prepollex, the presence or absence of a nuptial excrescence, and the kind of nuptial excrescence are important taxonomic characters of the thumb. Most species having an enlarged prepollex also have a nuptial excrescence, which is a smooth horny covering or composed of minute spin- ules (fig. 11R). The excrescence is made up of a cluster of large spines in members of the Ptijchohyla euthysanota group, Hyla echinata, Hyla pachyderma, and highland populations of Hyla lancasteri (fig. 11C). In Hyla zeteki, the prepollex is greatly enlarged and bulbous (fig. 11A), and in Hyla valanci- fer it is enlarged and spatulate; in both spe- cies a nuptial excrescence is absent. In Plec- trolujla, Hyla miliaria, and members of the Hyla albomarginata and boans groups, the prepollex is greatly enlarged and is supported by a prepollical spine, which protrudes through the distal end of the prepollex in B Fig. 10. Distal subarticular tubercles on fourth fingers. A. Normal, round. B. Bifid. C. Divided. 1970 DUELLMAN: HYLID FROGS 29 Fie. 11. Ventral views of right prepollices showing nuptial conditions in males. A. Hyla zeteki, enlarged and lacking nuptial excrescence. B. Hyla robertsorum, enlarged and having a generalized nuptial excrescence. C. Ptychohyla spinipollex with a cluster of nuptial spines. D. Hyla crepitans with elongately enlarged prepollex and protruding prepollical spine. some individuals (fig. 11D). The shape of the prepollical spine is an important taxo- nomic character in Plectrohyla (see account of that genus). In addition to those groups just mentioned, several others lack nuptial excrescences on relatively unenlarged prepol- lices— Acris, Anotheca, Hemiphractus, Pty- cholhyla schmidtorum group, and members of the Hyla colymba, godmani, leucophyllata, microcephala, mixomaculata, and rubra groups. An inner metatarsal tubercle is present in all species of Middle American frogs. The tubercle varies in size and shape from elon- gately elliptical to ovoid; in Pternohyla fo- diens, the edge of the tubercle is elevated and spatulate (fig. 4C). The outer metatarsal tu- bercle is small or absent in all species. Most students of hylid taxonomy have given considerable taxonomic weight to the presence or absence of a tarsal fold on the inner edge of the tarsus (fig. 4C). In many species, the fold is strong and flap-like; in others it is weak or absent. The status of the tarsal fold in many small species having weak folds is difficult to determine. In specimens that have been fixed in trays with the plantar surface down, the fold is obscured. Thus, in many individuals, it is not possible to deter- mine if a tarsal fold is present. A weak outer tarsal fold is present in some populations of Plectrohyla glandulosa. The extent of the webbing on the hands and feet shows a vast amount of interspecific variation. The feet are fully webbed and the hands nearly fully webbed in Agalychnis lito- dryas and spurrelli and in Hyla boons, crassa, mixe, nubicola, echinata, miliaria, and thysa- nota. Webbing is absent, or nearly so, on the hands and feet of Pseudacris, Pternohyla, Phyllomedusa, and Hemiphractus. Webbing is essentially absent on the hands of Acris, Anotheca, Gastrotheca, and some species of Hyla, but in these the toes are webbed. In the accounts of the species, the amount of webbing is expressed in general and in detail. The general terms of toes "two-thirds webbed" or hands "one-half webbed" are con- venient for expressing the amount of webbing present, so that quick comparisons can be made between species having noticeably dif- ferent amounts of webbing. The detailed description of the webbing takes into account the extent of the webbing (exclusive of a dermal fringe on the lateral surface of the phalanx, if present) on each side of each phalanx. Closely related species usually have about the same amount of webbing, but the details of the webbing may differ. For ex- ample, the extent of the webbing on the fourth finger is a character by which the Middle American members of the Hyla boans group can be distinguished from one another. On the other hand, the vestigial web between the first and second toes is constant in members of the Hyla rubra group (fig. 4D). The amount of webbing increases with age and size. The development of the webbing is especially noticeable in large species having nearly fully webbed hands and feet, such as Agalychnis spurrelli, Hyla boans, Hyla mi- liaria, and Phrynohyas vemdosa. Conse- quently, comparisons between adults and juveniles can lead to erroneous conclusions. Coloration Whereas the external structures of hylids are sometimes difficult to describe, the colors and in some species even the patterns are lost in preservative. I have seen living indi- viduals of all but 11 of the species of Middle American hylids. Detailed notes on colora- 30 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 tion and hundreds of colored photographs were taken. The importance of these cannot be over-emphasized. The coloration is the easiest way to identify most of the species (see pis. 41-72). Although the total array of colors in Mid- dle American hylids encompasses the entire visible spectrum, the frogs can be grouped into three categories on the basis of their dor- sal ground color (the color that is dominant and exclusive of the markings where present ) ; these are brown, green, and yellow. These basic colors occur in a ratio of 4:3:1, respec- tively. Thus, brown species outnumber yellow species four to one and are 25 per cent more frequent than green species. The patterns of the frogs can be roughly sorted into three types: plain, striped, and blotched or spotted. The ratio of blotched to plain to striped frogs is 8:6:1. Ry comparing pattern with dorsal ground color, we find that by far the most common combination is a brown frog with a blotched pattern (46 species), whereas eight brown species are plain and only four are striped. Of the 42 green species, 29 lack a dorsal pattern, and none is striped. Six of the 16 predominantly yellow species are plain, whereas four each are blotched or striped. The pattern on the dorsal surfaces of the limbs consists of transverse markings of vary- ing widths and distinctness in most species having a blotched or spotted pattern on the back. In most plain species, the dorsal sur- faces of the limbs are unmarked or have small darker flecks. Of the eight species that have a dorsal body pattern of stripes, only some populations of three of those species (Hyla ebraccata, microcephala, and staufferi) have linear patterns on the limbs. The thighs are unpigmented, or nearly so, in several small species, for example, members of the Hyla IcucophyUata and microcephala groups. Pigment is lacking in the axilla and groin in some stream-breeding frogs, such as members of the lhjla bistincta group and the genus Plcctrohyla. In many species of green frogs, especially those lacking dorsal markings, the outer edges of the forearms and feet are marked by a pale cream or white stripe, usually in these frogs, such as Agalychnis and members of the Hyla uranochroa group, a white line is present on the heel and above the anal opening. Pale labial stripes are common among green frogs and those lacking dorsal mark- ings. In other species, vertical bars are pres- ent on the lips; these markings are most com- mon in frogs with a blotched dorsal pattern. In some green frogs, such as Hyla uranochroa and Ptychohyla schmkltorum charmdae, a white spot is present below the eye. Other facial markings include a dark canthal and supratympanic line in many species and a broad dark brown or black postorbital mark that encompasses the tympanum, such as oc- curs in Smilisca and members of the Hyla cximia group. The ventral coloration is much more uni- form. In the majority of species, the venter, with the exception of the vocal sac in breeding males is white, creamy white, or pale yellow. In most of the exceptions, such as some spe- cies in the Hyla bistincta group and members of the genus Plcctrohyla, the venter is gray. Uniformly dark gray or brown venters occur in Anotheca, Gastrotheca, Hemiphractus, and in Hyla chaneque and taeniopus. Dark flecks or reticulations are present on the ventral sur- faces of Hyla rivularis, pictipes, and tica, whereas bold black spots are present on an otherwise white venter in Hyla thorectes and highland populations of Hyla lancasteri. Phyl- lomedusa vemista has an orange belly and brown throat and chest, the latter spotted with white. The colors on the flanks and anterior and posterior surfaces of the thighs are highly diagnostic in many species. In some species, these surfaces are unicolor and strikingly different from the dorsal coloration. For ex- ample, in Hyla loquax the dull grayish brown dorsum is in sharp contrast to the bright red anterior and posterior surfaces of the thighs. The flanks and thighs are spotted in many species; for example, bright blue spots are present on those surfaces in Smilisca cyano- sticta and sila. Pale yellow vertical bars are in sharp contrast to the otherwise blue flanks of Agalychnis callidryas, and vertical black bars stand out boldly against the golden orange flanks and thighs of Aglaychnis cal- carifer. Bold bars of contrasting colors, such as green and black in Hyla boidengeri, orange and black in Hyla rostrata, and white or pale yellow and black in Hyla lancasteri, are pres- ent on the posterior surfaces of the thighs in 1970 DUELLMAN: HYLID FROGS 31 some species. The webbing on the hands and feet of most species is not distinctively col- ored, but in some species, the color of the webbing is markedly in contrast with the dor- sal and /or ventral color. In the predomi- nantly brown frogs, Hyla loquax and Hyla pseudopuma infucata, the webbing is red, as it is in the green Hyla rufttela. The webbing is blue in Agalychnis annae and orange in Agalychnis moreletii, spurrelli, and calcarifer — all species having a green dorsum. The coloration of the iris is rather uniform within most species, but great differences exist among some species. Unfortunately, the color of the iris usually is lost or greatly altered soon after preservation. In living frogs, the color of the iris is most easily detected in bright sunlight when the pupil is contracted. In most Middle American hylids, the iris is a golden or bronze color with black flecks or reticulations. Some notable exceptions do exist. Frogs in the Hyla albomarginata and boons groups have creamy white irises with faint darker reticulations, and members of the Hyla parviceps group have an iris that is sil- very gray with a red periphery, whereas that in Phyllomedusa lemur is uniform silver. A deep copper colored iris occurs in some spe- cies, notably Anotheca spinosa and Hyla sal- vadorensis, and the iris is orange in Agalych- nis annae. A red iris occurs in nine species. In five species of Agalychnis and the two spe- cies of the Hyla uranochroa group, the iris appears to be covered with red enamel, whereas in Hyla legleri and Hyla erythromma the iris is a metallic red. I have no knowledge of the histological structure which might help to explain differences in these two kinds of red eyes. Geographic Variation in Color Minor differences in color and/or pattern are common in many species of hylids. Usu- ally the amount of variation within samples is nearly as great as that between samples; con- sequently, meaningful analyses of geographic variation in coloration is not possible for most species. However, notable geographic varia- tion is apparent in a few species. The dorsum is uniform reddish brown in Ptychohyla schmidtorum on the Pacific slopes of Guate- mala and Chiapas and is bright green on the Atlantic slopes of Chiapas. Geographic vari- ation in dorsal pattern occurs in Hyla eximia, microccphala, and staufferi and in Phryno- hyas venulosa. In the former, the dorsal pat- tern is highly variable (plain, spots, or linear arrangement of spots), but the percentage of individuals having the different patterns var- ies geographically. In northern populations of Hyla microcephala, the dorsal pattern consists of irregular and interconnected lines and dashes; in southern populations, the pattern consists of parallel longitudinal lines. North- ern and southern populations of Hyla staufferi differ in the markings on the dorsal surfaces of the shanks. The dorsal pattern in Phryno- hyas venulosa consists of a large dorsal blotch. In western Mexico, the blotch is fragmented transversely in most specimens, whereas many specimens in eastern Mexico have the blotch longitudinally divided anteriorly. Many speci- mens from lower Central America have a narrower blotch than do those from the north- ern part of the range. A unicolor variety of Phrynohyas venulosa occurs in Central Amer- ica and southern Mexico; intermediate colora- tion exists between the normal pattern of a large blotch and the unicolor variety. The color of the flanks in Agalychnis calli- dryas varies from dull bluish brown to deep bluish purple, and the presence or absence of a longitudinal white line and the number of vertical white bars varies geographically. Hyla pseudopuma has tan webs and posterior surfaces of the thighs throughout most of its range, but on the Atlantic slopes in Panama, the webs and thighs are red. Polymorphism Some species of Middle American hylids exhibit a variation in coloration that seems to be polymorphic. The generally accepted defi- nition of polymorphism is "the simultaneous occurrence of several discontinuous pheno- types or genes in a population, with the fre- quency of the rarest type higher than can be maintained by recurrent mutation" ( Mayr, 1963, p. 670). Goin (1960b and papers cited therein ) and Lynch ( 1966a ) have documented cases of pattern polymorphism in Eleuthero- dactylus. Volpe (1955 and 1961) com- 32 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 mented on this kind of variation in Rana, and Pyburn ( 1961 ) discussed the occurrence of polymorphism in Acris. Evidence for pattern polymorphism in Middle American hylids is circumstantial. The small series of Hyla altipotens and pinonun available each contain individuals having a dorsal pattern of blotches and others with a middorsal stripe. The dorsal patterns are of four types in Hyla ebraccata: plain, spotted, triangle, or hour-glass. All specimens can be allocated to one of these four types; inter- mediate patterns apparently are lacking. Large series of specimens or preferably breed- ing experiments are desirable in order to de- termine if these species actually do exhibit pattern polymorphism. Sexual Dimorphism The most common kind of sexual color difference is in the development of a pig- mented vocal sac in the breeding males of many species. In the small yellow species of Hyla in the microcephala, picta, and leueo- phyllata groups, the vocal sacs are bright yellow in breeding males, whereas in other species, the vocal sacs are either white, dark gray, or brown. The dorsal coloration usually is not sexu- ally dimorphic, but two notable exceptions oc- cur in Middle American hylids. In males of Hyla pictipes, the dorsum is green with dark brown or black mottling; in females, the dor- sum usually is uniform green. Furthermore, in females numerous yellow spots are present on the flanks and thighs; these are inconspicu- ous or absent in males. In the Central Ameri- can Hyla subocularis and the South American members of the Hyla parviceps group, the females have a conspicuous dorsolateral pale band, which is absent in males. Females of Hyla chaneque and in some populations of Hyla taeniopus tend to have darker venters than the males. Ontogenetic Change Few of the diagnostic features of the adult coloration are evident in recently metamor- phosed young. Bars, spots, or mottling on the flanks and thighs develop after the dorsal and ventral pattern are evident. Even the color of the iris changes with age in some species. Ontogenetic change in coloration is well documented in few species; these are dis- cussed below. Juveniles of Smilisca baudinii are uni- formly dull green above and lack markings on the thighs and flanks. Characteristically, they have a broad white or pale cream spot below the eye; this spot persists as a pale area be- tween dark vertical bars on the lips of adults, which develop large blotches on the dorsum, transverse bars on the limbs, and mottling on the flanks. Juveniles of Hyla taeniopus are bright green with numerous black flecks on the dorsum. With increased size, there is a gradual change from many small black flecks to fewer large spots, which in many specimens are fused to form irregular blotches. In Hyla angustilineata the young have a bright green dorsum, which changes to brown in adults. Juveniles of Pternohyla fodiens are green, usu- ally without a pattern; whereas adults are tan with brown blotches. A striking ontogenetic change takes place in the coloration of the flanks and thighs in Smilisca cyanosticta. Recently metamor- phosed young have pale tan flanks, and the posterior surfaces of the thighs are orange- yellow; spots are absent. Slightly larger ju- veniles have tan flanks and red thighs, both lacking spots; later the flanks become dark brown with blue spots, and the thighs re- main the same. Adults have dark brown flanks and thighs, both with blue spots. The development of color pattern in Aga- lychnis callidryas was described by Starrett (1960a, p. 30), who noted that the white lateral stripe did not develop until about the time the tail was completely absorbed; the blue color and vertical white bars on the flanks did not develop until several weeks later. In most of those hylids having a golden or bronze-colored iris in adults, the iris in ju- veniles is pale golden without apparent dark flecks or reticulations. Juveniles of Hyla taeni- opus have a metallic green iris; larger indi- viduals have a pale bronze iris, and adults have a bronze iris with a darker, copper- colored periphery. The deep red iris of Hyla rufiocidis and nranochroa develops in the tadpoles, but the red iris in Agalychnis de- 1970 DUELLMAN: HYLID FROGS 33 velops after metamorphosis. Juveniles of Agalychnis callidryas have a yellow iris; the red color develops about two weeks after metamorphosis (Starrett, 1960a, p. 30). Metachrosis The ability to change color is well docu- mented in hylids (see Duellman, 1961c, Duell- man and Trueb, 1966, and Duellman and Fouquette, 1968, for comments on Middle American species). Metachrosis is the rule, rather than the exception, in most of the species. Parker (1948) summarized previous work, mostly experimental in laboratories, on amphibian color changes and stated that frogs respond to cool dark environments by the release of melanophorotropic hormone and darkening of the integument, whereas light and warmth result in melanophore contrac- tion and light colors through the retention or nonsecretion of hormones by the pituitary. Edgren (1954) carried out laboratory experi- ments on Hyla versicolor and concluded that versicolor responds to light by the expansion of melanophores and to darkness by the con- traction of the melanophores. Thus, according to Edgren, Hyla versicolor is paler at night than by day. The contradictory nature of these reports is supported by field observa- tion on Middle American hylids. Most of the species can be grouped into one of two cate- gories depending on the positive or negative correlation of color with the amount of light. Many pond-breeding species are conspicu- ously paler at night than by day. Notable ex- amples include the members of the Hyla god- mani, leucophyllata, microcephala, and picta groups, plus Hyla elaeochroa and staufferi. In many of these species, the entire dorsum is pallid at night, and the dorsal pattern is faint and inconspicuous. By day, the dorsal ground color is darker and the markings are conspicu- ous. Hyla miotympanum is pale green at night and changes to dark green or mottled green and brown by day (pi. 56). Contrary to the darker coloration by day characteristic of the groups listed above, other species are darker at night. Hyla arenicolor and crepitans are brown at night; both are capable of changing to pale tan or pale ashy gray by day. The colors in the various species of Agalychnis are darker and more intense at night. Striking changes take place in Agalych- nis saltator and Phyllomedusa lemur. At night, both species are brownish lavender, and by day they are pale green (pis. 42 and 43). The two opposing trends in color change do not seem to be correlated with habits or habitat, and at this time no reasonable ex- planation for differential reaction to light stimulus is available. Tadpoles The tadpoles reflect different kinds of adaptations to entirely different environments from the adults. Consequently, correlation between the larval features and those of the adults frequently is lacking. A great variety of morphological types is present among the Middle American hylid frogs. One of our foremost students of tadpoles, Priscilla Star- rett, once said that the most bizarre type of tadpoles develop into ordinary frogs, whereas highly distinctive species of frogs usually have very ordinary looking tadpoles. This observa- tion, which might be termed Starrett's Law, certainly seems to hold true for the Middle American hylids. Hyla zeteki and sumichrasti, as examples, have no very distinctive features as adults, but as tadpoles they are highly modified. On the other hand, the bizarre casque-headed species of Triprion have very ordinary tadpoles that are difficult to distin- guish from the majority of other pond-type of tadpoles. All tadpoles have been staged according to Gosner's (1960) developmental table. Ac- curate comparisons can be made between in- dividuals of the same developmental stage; if differences exist between two tadpoles in different developmental stages, these differ- ences possibly are due to the relative ages of the tadpoles. Whenever possible, I have se- lected for purposes of description, tadpoles in developmental stages 28 through 34, be- cause after considerable experience, I have found that in these stages the mouthparts are fully developed, and no obvious metamorphic modifications have taken place. Measure- ments of small tadpoles were made with the aid of an ocular micrometer and a dissecting microscope; the larger tadpoles were mea- sured with dividers under a dissecting micro- scope. The body length is that distance be- 34 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 tween the tip of the snout and the posteroven- tral edge of the body, and the tail length is taken from the posteroventral edge of the body to the tip of the tail (fig. 12). In rela- tively unmodified tadpoles the length of the tail is approximately two-thirds of the total length of the tadpole. The relative length of the tail to that of the entire tadpole is given as less than two-thirds (< 2/3), equals two- thirds (=2/3), or greater than two-thirds ( > 2/3). The shape of the body is described as follows: ovoid (depth equal to width), robust (depth slightly greater [< 15%] than width), deep (depth much greater [5: 15%] than width), or depressed (depth less than width ) . The relative depths of the caudal fins and of the caudal musculature are based on proportions taken at the midlength of the tail and are given as the relative depth of the dorsal and /or ventral fin to the caudal muscu- lature. The dorsal caudal fin can be described as follows: normal (present throughout length of tail but not extending anteriorly onto the body), or reduced (depth greatly reduced or fin absent on part of tail). Most hylid frogs have a sinistral spiracle and a dextral anal tube (cloaca). The position of the spiracle and the direction of the spiracular opening is of some taxonomic importance. The position and structure of the mouth is one of the most obvious characters in tad- poles (fig. 13). Among the Middle American hylids, four different positions of the mouth are evident. These are dorsal, terminal, an- teroventral, and ventral. In some species, the mouth is situated anteroventrally but directed ventrally; for purposes of analysis, these tad- poles are considered to have a ventral mouth. The width of the mouth is given in relation to i— Nostril -Body Length ' s — Anal Tube Total Length Tooth Rows Beaks: Upper ^ Upper 1st \ a ^V* ^\uniN,lu»Hi|V(t-^^>^H * Lower 2nd\V^ rtrtH",,,,"","""l"i'»iiitSimit»»wl iiiiiii""'""'""(i. Lower ,,i ■■!.■ •■■I,,,,, i Lateral Fold Fig. 12. Hylid tadpole showing certain structures and places of measurements. Labial Papillae Fig. 13. Diagrammatic view of the mouth of a generalized hylid tadpole showing labial and buccal structures. the greatest width of the body; although this is an extremely difficult character to measure, I have attempted to categorize the relative size of the mouth. In general terms, I recog- nize the tadpoles having three sizes of mouths; these are small (less than two-thirds of the width of the body), medium (greater than two-thirds of the width of the body, but less than the width of the body ) , and large ( width of the mouth greater than the width of the body). In most hylid tadpoles, the lips are infolded laterally, but in some species the folds are lacking, and in others the mouth is expanded into a funnel-like structure. The edge of the mouth is either completely or partially bordered by one or more rows of papillae; if the mouth is only partially bor- dered, at least the median part of the upper lip is devoid of papillae. The number of rows of papillae is a taxonomically important char- acter. Usually only one or two rows of fring- ing papillae are present; however, in some groups the papillae are much more numerous. For example, in Hyla rividaris there are four to six rows of papillae on the lower lip. In tadpoles of the Hyla bistincta group and in the genus Plectrohyla, the fringing rows of pa- pillae are bordered medially by an irregular row of noticeably larger papillae. There are many morphological adaptations in tadpoles of Middle American hylids. These adaptations are closely correlated with the environments in which the tadpoles develop. Usually those tadpoles that develop in ponds 1970 DUELLMAN: HYLID FROGS 35 have relatively short, high caudal fins and rather slender caudal musculature. These tad- poles have either an anteroventral or an an- terior mouth. Tadpoles that develop in streams usually have proportionately much longer tails with lower fins and more robust caudal musculature. Furthermore, these tad- poles have either an anteroventral or ventral mouth which in many species is enlarged and modified into a sucker-like apparatus for at- Fic. 14. Body shapes of tadpoles of Middle Ameri- can hylids. A-C. Pond types: A. Smilisca puma. B. Hyla boule7igeri. C. Hyla phlebodes with xiphicercal tail. D and E. Stream types: D. Hyla rivularis with enlarged mouth and folded lips. E. Hyla uranochroa with funnel-shaped mouth. F and G. Bromeliad types: F. Hyla bromeliacia with depressed body. G. Hyla zeteki with anterodorsal mouth. tachment to rocks in streams. Tadpoles that develop in bromeliads usually have relatively long tails with heavy caudal musculature and reduced fins (fig. 14). The size, shape, and structure of the horny beaks are useful taxonomic characters (fig. 15). Well-developed beaks are present in all known Middle American hylid tadpoles; in most of these, the beaks have some kind of serration. The horny "teeth" in tadpoles are arranged on transverse ridges and termed "tooth rows." The majority of hylid frogs have two upper (anterior) rows of teeth and three lower (posterior) rows. Some species lack teeth entirely, whereas other Middle American species have as many as seven upper and 11 lower rows. Although the num- ber of tooth rows is highly important taxo- nomically, the lateral extent of the rows and the presence of medial interruptions is also significant. Unfortunately the colors of tadpoles change more drastically than those of the adults once the animals are placed in pre- servative. Some kinds of tadpoles actually have gaudy coloration; this is especially true of those of the South American groups. For example, the tadpole of Hyla ebraccata has broad vertical red, white, and black bands on the tail; in Hyla microcephala, the caudal fins are transparent except for an orange periph- ery. The tadpoles of Agalyclmis usually are pale blue in life. Although the subtle colors disappear in preservative, some aspects of the pattern usually are evident. The presence of bold mottling or transverse bands on the tail are useful characters in aiding in the identifi- cation of certain tadpoles. Tadpoles of only 84 of the species of Mid- dle American hylid frogs are known. Con- sequently, a key has not been prepared for the identification of the tadpoles. Instead, a table of the diagnostic features has been pre- pared (table 2). I think that the diagnostic- characters listed therein, in combination with the descriptions given in the text should suffice for the identification of any of the known hylid tadpoles from Middle America. Several generalities can be drawn from the analysis of the features of the tadpoles of Middle American hylid frogs. For ex- ample, the combination of two upper and 36 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 three lower rows of teeth is prevalent in tad- poles from various geographic regions and inhabiting various ecological situations. How- ever, the presence of more than two upper and three lower rows of teeth in pond-type tadpoles occurs only in South American groups [Hyla dlbomarginata and boans groups (2/4) and Phrynohyas (3/4-6)]. The number of rows of teeth is reduced in egg-eating tad- poles (1/1 in Hyla zeteki; 2/2 in Anotheca). However, Acris crepitans also has only two upper and two lower rows of teeth. Rows of teeth are absent only in those tadpoles having terminal mouths, and these belong only to certain South American groups (Hyla leucophyllata, microcephala, and parviceps groups). In these same groups, the tails are xiphicercal; a tendency toward this type of tail also is present in some members of the South American Hyla rubra group. The greatest proliferation of tooth rows is found in tadpoles inhabiting streams. Here it is interesting to note that although there are numerous stream adapted tadpoles in the highlands of lower Central America and that many of these tadpoles have enlarged mouths (such as Hyla pictipes and rivularis), the great majority of species do not have a pro- liferation of tooth rows. On the other hand, the enlargement of the mouth in tadpoles in the highlands of Central America and in the highlands of Mexico usually is accompanied by a proliferation of tooth rows. Two excep- tions are noted in lower Central America; these are Hyla legleri (an apparent invader from the north) having two upper and five lower rows of teeth, and Hyla colymba (ap- parently a South American species) having six upper and nine lower rows of teeth. Not all of the stream tadpoles in northern Middle America have enlarged mouths and an in- creased number of tooth rows. For example, the stream-adapted tadpoles of the Hyla bi- stincta group and of Plectrohyla all have two upper and three lower rows of teeth con- tained in a relatively small mouth. However, -> ^M"imiiffiiijiiiitii'ii'UfMi'i'uJto ,0" ^ Fig. 15. Mouths of hylid tadpoles showing adap- tive modifications. A. Generalized pond type, Smilisca puma. B. Enlarged and ventral stream type, Hyla pinorum. C. Terminal pond type, Hyla ebraccata. D. Funnel-shaped stream type, Ptychohyla ignicolor. 1970 DUELLMAN: HYLID FROGS 37 these tadpoles do have moderately long, tre- mendously muscular tails with low fins and a ventral mouth. One of the most striking modi- fications of the mouth in Middle American hylid tadpoles is the development of a funnel- shaped mouth. This type of mouth is present in two closely related species of the Hyla uranochroa group in lower Central America and in two closely related species on Ptycho- hyla in Mexico and Guatemala. In these tad- poles the mouth has a complete border that is expanded and bears few small papillae on the border. It is interesting to note that tad- poles having mouths such as these have not only a reduced number of tooth rows, but the length of the existing rows is greatly re- duced. It seems as though the teeth in these tadpoles are less important in grasping or holding than in those tadpoles not having a funnel-shaped mouth. The careful study of the larval morphology and a comparison of the physical features of the tadpoles with the environment in which they live provide certain clues towards gen- eral evolutionary trends in hylid tadpoles. It seems only reasonable that the generalized type of pond-tadpole probably most closely approximates the larva of the hylid prototype. I visualize a primitive hylid tadpole to be a pond dweller and to have an ovoid body, tail equal to about two-thirds of the total length, moderately developed caudal musculature, generalized caudal fins probably not extending onto the body and equal in depth to the caudal musculature, a medium or small an- teroventral mouth having an incomplete fringe of labial papillae, moderate lateral folds and two upper and three lower rows of teeth. A tadpole of this type approximates the gen- eralized leptodactylid tadpoles and therefore is in line with the present concepts of the ancestory of the family Hylidae. From a generalized hylid tadpole three general evolutionary trends are evident, into the streams (lotie), ponds (lentic), and ar- boreal environments. Adaptations for the lotic environments include shallower, more stream- lined body, a proportionately longer tail with heavier caudal musculature and shallower fins, and a large ventral mouth. The modifica- tions of the mouth are divergent at this point into either a greatly enlarged mouth with an increased number of tooth rows and a pro- liferation of labial papillae or to a funnel- shaped with the loss of the lateral fold and a reduction in the number of teeth and papillae. The adaptations to a lentic environment in- clude an increased depth of the fins, the ex- tension of the dorsal fin onto the body, which is deep. Further modifications include the development of a ventral spiracle, or the de- velopment of a terminal mouth lacking teeth and papillae. Arboreal adaptations include the development of a long tail with reduced fins and a ventral mouth, or a mouth modified for eating frog eggs. One thing is obvious from the examination of the tadpoles and the correlation of the larval characteristics with the features of the adults; the various structural modification of the tadpoles do not necessarily indicate phy- logenetic relationships. In other words, all species of hylid frogs having tadpoles adapted for a stream existence are not necessarily re- lated to one another. Likewise, frogs having arboreal tadpoles are not necessarily related. By taking a generalized pond-type tadpole as an example of a primitive hylid, I have im- plied the evolutionary direction from pond to stream and from pond to arboreal habitat for hylid tadpoles. Likewise, I have indicated the evolutionary direction of various physical modifications of the tadpoles. The evolu- tionary trends in the mouthparts of stream tadpoles is for an increase in the size of the mouth, the development of a complete labial fringe of papillae, an increase in the number of rows of papillae, and an increase in the number of rows of teeth. Consequently, it is entirely possible that in Mexico, the rather generalized stream tadpole of Hyla miotym- panum could have developed from a general- ized pond-type of tadpole and could have given rise to the tadpole of Hyla arborescan- dens, which differs from miotympanum by having one additional lower row of teeth and by having the labial border completely bor- dered by papillae. A tadpole of the Hyla arborescandens-type could have given rise to tadpoles of the Hyla pinorum group by the addition of one more lower row of teeth and one more row of fringing papillae. 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Similar types of tadpoles in the highlands of lower Central America and also in the highlands of South America suggest that the morphological modifications of tadpoles for lotic environments have undergone a consid- erable amount of parallel evolution. Although some of the structures in tadpoles are similar from widely different areas, usually the com- binations of structures are sufficiently differ- ent, so that the tadpoles can be adequately placed in their own phyletic groups in partic- ular geographic regions. Whereas the trend in lotic environments is towards the proliferation of mouthparts and elongation of the tail with a corresponding decrease in surface area, the opposite is true in modifications for a truly lentic environment. In the quiet water, the tadpoles maintain their positions by a fluttering action of the posterior part of the tail. In some kinds of tadpoles, such as those in the Hyla leucophyllata, micro- cephala, and parviccps groups, the tip of the tail is drawn out into a xiphicercal pattern. When in a resting position, only this protrud- ing tip of the tail flutters. The deep caudal fins and the anterior extension of the dorsal fin onto the body aid in providing a tremen- dously large surface area to the tail, which is powered by relatively weak musculature. The mouth in lotic tadpoles is utilized for maintenance of position by adherence to a rock on the bottom of a stream, whereas the mouth in lentic tadpoles functions only for ingestion of food. Some of the lentic tadpoles feed on aquatic plants; others apparently feed at least partially on phytoplankton. In some of the lentic tadpoles, the labial papillae are reduced in number or completely lost and the teeth are missing, so that the mouth consists merely of a pair of fleshy folds surrounding the horny beaks. The tadpoles that develop in arboreal sit- uations have certain obvious morphological modifications, principally a small depressed body and an elongate tail having reduced fins. However, the physiological adaptations must be even more striking than the morphological ones, because these tadpoles develop in ex- tremely limited quantities of water, in which there is a considerable amount of decaying vegetable matter and consequently a rela- tively low amount of dissolved oxygen. The apparent shortage of food in the arboreal situations (bromeliads or water-filled cavities in trees) has been met successfully by the habit of ingestion of frog eggs. At this time it can only be supposed that the eggs ingested are those of the same species. A discussion of the tadpoles of Middle American hylids would not be complete with- out mentioning those species that lack an aquatic larval stage — the two species of Gas- trothcca and the one of Hemiphractus that occur in Middle America. Insofar as known, the eggs of Gastrotheca develop directly into small frogs in the brood pouch of the female, whereas the eggs carried on the back of the female Hemiphractus develop directly into small frogs, which are attached to the back of the female by four tiny cords (pi. 7 ) . It is obvious that the evolutionary adapta- tions of the larval stages of hylid frogs have been extremely important in the dispersal and probably speciation of the group as a whole. Ecological preferences of tadpoles are evident. In some streams, the species of tadpoles seg- regate nicely into pools versus ripples. In ponds, tadpoles of certain species seek sunny areas, whereas others are found only in the shade. Observations on the ecology and be- havior of tadpoles are extremely limited, and much further work remains to be done on this subject. The present observations only hint at the possibilities for future work and under- standing. Cranial Osteology Until recently, knowledge of the variation in cranial elements of hylid frogs was ex- tremely meager. Duellman (1964b) used cranial characters in defining the Hyla bi- stincta group. Brief descriptions of cranial structure have been given for Phrynohyas (Duellman, 1956a) and Phjchohyla (Duell- man, 1963c), and specific and sexual differ- 44 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 ences in the skulls of Htjla chaneque and taeniopus were pointed out by Duellman ( 1965b ) . Duellman and Trueb ( 1966 ) , Duell- man and Fouquette (1968), and Leon (1969) used cranial characters in defining species groups and in showing differences between species in Smilisca and in the Hula micro- cephala and rubra groups, respectively. Trueb ( 1968b ) presented a description of the in- ternal cranial osteology of Smilisca baudinii. The only extensive comparisons of cranial osteology of hylicl frogs are in Trueb's ( 1970a ) study of the casque-headed hylids. Data on the cranial osteology have been accumulated on 101 of the species of Middle American hylids. These data have been es- pecially helpful in defining most of the genera and species groups, although cranial char- acters are of limited use in some of the groups of stream-breeding hylids in Mexico, in which the cranial elements are considerably reduced. Obvious differences exist in the presence or absence of certain elements or processes, whereas more subtle differences exist in the shapes and relative development of other elements. Most differences occur in the der- mal elements. Several problems have been encountered in the comparative study of the cranial oste- ology. Generally, the larger individuals of a species have more fully ossified skulls than do smaller individuals, even though the latter are sexually mature. Thus, whenever possible, osteological characters were studied on the largest available specimens. Comparisons be- tween dried and cleared and stained speci- mens are difficult due to the differential pres- ervation and to light refraction in cleared and stained specimens; however, an experienced eye can determine the nature of the bones. Each of the cranial elements and their various processes are defined and the variation in these elements is discussed below. The terminology is the same as used by Trueb ( 1970a ) , and the cranial bones are illustrated in figure 16. Dermal Elements Angulosplenial: Paired bones in lower jaw lying medial and ventral to Meckel's cartilage. No variation of taxonomic significance was noted. Dentarij: A bone in the lower jaw; it is located anterolaterally to Meckel's cartilage and articulates anteriorly with the mento- meckelian. No variation of taxonomic signifi- cance was noted, except the presence of a pair of odontoids anteriorly in Hemiphractus. Dermal Sphenethmoid: The dorsal, der- mal component of the endochondral sphen- ethmoid (fig. 17D). This element, which was first defined by Trueb (1966, p. 563), is co- ossified with the overlying skin, completely fused with the underlying endochondral sphenethmoid, and usually articulated with the nasals anteriorly and frontoparietals pos- teriorly. This element is present in only two Middle American species, Gastrotheca cera- tophnjs and Triprion petasatus. Frontoparietal: Paired dermal roofing bones overlying the sphenethmoid and prootic. In most hylids, the frontoparietals are separated medially exposing all or part of the frontoparietal fontanelle (fig. 17C). Premaxillar Maxillary Prevomer Palatine Sphenethmoid Frontoparietal Squamosal Columella Parasphenoid Exoccipital Fig. 16. Ventral (A) and Dorsal (B) views of a generalized hylid skull with terminology of cranial bones. 1970 DUELLMAN: HYLID FROGS 45 Premaxillary Pars Palatina Maxillary—^ Posterior Process Maxillary Palatine Process Prevomer ^Pars Palatina Frontoparieta Fontanelle Internasal Crista Parotica Dermal Sphenethmoid Prenasal Fig. 17. Cranial characters of hylid frogs. A. Lat- eral view of anterior part of skull. B. Ventral view of anterior part of skull; shaded area shows extent of prevomers in those species in which they articulate with the premaxillaries. C. Dorsal view showing posi- tion of internasal in Pternohyla fodiens and nature of frontoparietal flanges in Smilisca baudinii. D. Dorsal view of Triprion petasatus showing prenasal and dermal sphenethmoid. This fontanelle is an oval opening in the en- dochondral cranial roof; the fontanelle is formed in the sphenethmoid anteriorly and the prootic posteriorly and covered by mem- braneous connective tissue. In some species, there is a median encroachment of the fronto- parietals over the fontanelle so that the fon- tanelle appears to be long and narrow; in those species, in which the frontoparietals are not expanded medially, small amounts of cal- cification occur in the membraneous connec- tive tissue covering the fontanelle. The fontanelle is completely covered by the fron- toparietals in Phrynohijas, Anotheca, Gastro- theca, Pternohyla, Triprion, a few species of Hyla (especially noteworthy are some mem- bers of the Hyla rubra group) and one species of Smilisca (phaeota). The lateral margins of the frontoparietals are straight and even (the normal condition, see fig. 17B) in most species but they are expanded laterally over the orbits in Anotheca, Gastrotheca, Phyllo- meclusa venusta, Pternohyla and Triprion and partly so in Smilisca baudinii and phaeota (fig. 17C). Internasal: A median roofing bone lying anterior to the nasals and between the ex- ternal nares (fig. 17C). Trueb (1970a) named this bone and noted its presence in Pterno- hyla fodiens. Maxillary: Paired dermal dentigerous bones forming the major part of the upper jaw. In all Middle American hylids, teeth are present on the maxillary, which articulates with the premaxillary anteriorly and in some species with the quadratojugal posteriorly. The pars facialis is the dorsomedially inclined flange of bone arising from the dorsal surface of the longitudinal axis of the maxillary (fig. 17A). The pars facialis is absent in Hyla smaragdina. In most species, the pars facialis does not articulate with the nasal; partial articulation is present in Hemiphractus pana- mensis, Hyla picadoi and siopela, Pternohyla dentata, Smilisca puma, and in members of the Ptychohyla euthysanota group. The pars facialis completely articulates with the nasal in Anotheca, Pternohyla fodiens, and both species of Triprion. The posterior process of the pars facialis (fig. 17A) is a dorsal expan- sion on the posterodorsal surface of the pars facialis. The process is absent in most small 46 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 species, in most of the stream-breeding spe- cies of Hyla, and in the casque-headed frogs of the genera Pternohijla and Triprion. In the larger frogs (Anotheca, Gastrotheca, Hemi- phractus, Pachymedusa, Phrynohyas, Phyllo- inedusa venusta, Plectrohyla, Smilisca, and members of the Hyla albomarginata, boans, miliaria, and taeniopus groups) plus several medium-sized species of Hyla, such as the Hyla lancasteri, pseudopuma, and zeteki groups, and the euthysanota group of Ptycho- hyla, the posterior process of the pars facialis articulates with the maxillary process of the nasal. In the other species, the posterior process is present but not articulating with the maxillary process of the nasal. The lingual flange of the maxillary is called the pars palatina (fig. 17B). This flange is conspicu- ous in Agalychnis, Pachymedusa, Phyllome- dusa, Pternohijla fodiens, the euthysanota group of Ptychohyla, Smilisca (except puma), Triprion spatulatus, and several species of Hyla. The pars palatina is absent in Hemi- phractus panamensis and present, but incon- spicuous, in other Middle American hylids. A distinct labial flange is present on the maxil- lary in Pternohijla and Triprion. Nasal: Paired dermal roofing bones over- lying the olfactory capsules anterior to the sphenethmoid. The nasals are highly variable in shape and in the amount of articulation with other bones. In some species, the nasals are small, slender elements that do not articu- late with the sphenethmoid posteriorly or with one another medially. This is the condi- tion characteristic of several species of small Hyla, such as bromeliacia, dendroscarta, mio- tympanum, phlebodes, and pinorum, plus the large frogs of the Hyla boans groups. In most frogs in which the nasals are reduced, the maxillary process of the nasal is absent or not articulating with the posterior process of the pars facialis of the maxillary; frogs of the Hyla boans group are an exception. The nasals are expanded and in contact medially with one another and articulate posteriorly with the sphenethmoid in Anotheca, Gastro- theca, Hemiphractus, Pachymedusa, Phyllo- medusa, Phyrnohyas, Pseudacris, Pternohijla, Triprion, and in members of the Hyla leuco- phyllata and rubra groups, plus a scattering of other species of Hyla. In Acris, Agalychnis, Plectrohyla, Ptychohyla, Smilisca, and the other species of Hyla the nasals are moder- ately developed. Palatine: Paired supportive bones at the anterior end of the orbit. In most species, the palatine articulates laterally with the maxillary and medially with the spheneth- moid, whereas the bone is reduced in some species. The palatine lacks an articulation with the sphenethmoid in Hyla pentheter and Triprion petasatus and an articulation with the maxillary in Hyla angustilineata and walk- eri. The bone is reduced to a small completely non-articulating element in Hyla sumichrasti and Pseudacris clarkii and absent in Hyla smaragdina and staufferi. In most species of Hyla, all Middle American species of Acris, Agalychnis, Gastrotheca, Pachymedusa, Pseu- dacris, and Ptychohyla, some species of the genera Plectrohyla, Phyllomedusa, and Smi- lisca, and in Triprion petasatus the ventral surface of the palatine is smooth or bears a smooth ridge. In all other species, an irregu- lar or serrate ridge is present. The ridge is irregular in Phrynohyas venulosa, Phyllome- dusa venusta, Plectrohyla ixil and matudai, Pternohijla dentata and fodiens, Smilisca cya- nosticta, and four species of Hyla ( lancasteri, miliaria, picadoi, and tica ) , whereas the ridge is noticeably serrate in Hyla cadaverina, Hemiphractus panamensis, and Triprion spatulatus. Parasphenoid: A median vesting bone ventral to the prootic and the posterior part of the sphenethmoid. Among the Middle American hylids, the parasphenoid is smooth in all species, except the two species of Tri- prion, in which a median longitudinal patch of odontoids is present. Premaxillary: Paired dentigerous bones forming the anterior margin of the upper jaw and articulating laterally with the maxillaries and medially with one another. The dorsal process of the premaxillary is the alary process (fig. 17A). The alary process is single in all Middle American hylids, except Plectrohyla, in which it is bifurcate (fig. 18). The an- terodorsal tip of the alary process lies adjacent to the nasal cartilages anteroventral to the nasals, and the posteroventral ramus extends beneath the anterior part of the spheneth- moid, thereby providing support for the en- 1970 DUELLMAN: HYLID FROGS 47 tire nasal region and anterior end of the sphenethmoid. The alary processes of the premaxillaries are inclined posteriorly in most species having rounded, or sloping snouts and are vertical in most of those with truncate snouts. The processes are slightly inclined anteriorly in two of the species having pro- truding snouts (Hyla rostrata and Pseudacris clarkii) and strongly inclined anteriorly so as to lie within the prenasal in Triprion. The lingual flange, pars palatina ( fig. 17B ) , of the premaxillary is conspicuous in Agalychnis, Anotheca, Hemiphractus, Pachymedusa, Phyl- lomedusa, Smilisca, the euthysanota group of Ptijchohyla, and many species of Hyla, whereas in other Hyla, Acris, Phrynohyas, Plectrohyla, Pseudacris, Ptemohyla, Triprion, and the schmidtorum group of Ptijchohyla the pars palatina is inconspicuous. The palatine process is a small posteromedial projection on the pars palatina of the premaxillary (fig. 17B ) . The palatine process is absent in Hemi- phractus and inconspicuous in Acris, Pseuda- cris, Triprion, and in some species of Hyla, Ptijchohyla, and Ptemohyla, whereas the process is conspicuous in all other Middle American hylids. Prenasal: A median bone lying anterior to the maxillaries, premaxillaries, and nasals, and forming the anterior end of the snout in Triprion and the South American Aparasphen- odon (fig. 17D). Prevomer: Paired investing bones lying ventral to the solum nasi of the olfactory cap- sule. The prevomers are variously developed and they articulate anteriorly with the maxil- laries and/or the premaxillaries (fig. 17B) in Anotheca, Gastrotheca, Hemiphractus, Pachy- medusa, Plectrohyla (except guatemalensis) , Phyllomedusa (except lemur), Smilisca, Tri- prion, and in some species of Hyla, notably members of the boam, lancasteri, miliaria, and rubra (boulengeri and rostrata) groups, plus Hyla angustilineata, chaneque, and thorectes. Usually the prevomer forms the anterior and medial margins of the internal choanae; how- ever, the lateral processes of the prevomers are reduced so as not to form the margins of the choanae in Hyla pentheter and picadoi, and in Hemiphractus reduced to a slender arcuate bone which likewise does not form the margins of the choanae. The prevomer normally has a transverse or slightly inclined dentigerous process bearing two or more teeth. The processes are greatly reduced in size and lack teeth in some specimens of Hyla smaragdina, smithii, and sumichrasti, and the dentigerous processes are lacking in Hyla picta and Phyllomedusa lemur. The dentiger- ous processes are elongate and angulate in members of the Hyla boons and albomargi- nata groups (fig. 19). True teeth are absent, but odontoids are present on the prevomers in Hemiphractus. Pterygoid: Paired, triradiate, supportive bones in the posterolateral part of the skull between the articular region, otic capsule, and suborbital part of the maxillary. The medial ramus of the pterygoid has a bony connection with the prootic in Anotheca, Gastrotheca, Hemiphractus, Pachymedusa, Phyllomedusa venusta, Phrynohyas, Plectrohyla, Pseudacris, some Agalychnis and Ptijchohyla, and in cer- tain species groups of Hyla (albomarginata, bistincta, boons, cohjmba, erythromma, lan- Fic. 18. Premaxillaries. A. Bifid alary process in Plectrohyla. B. Single alary process in other genera. Fig. 19. Dentigerous processes of prevomers as seen in the roof of the mouth. A. Transverse between the choanae. B. Angulate as in the Hyla boans and albomarginata groups. 48 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 casteri, loquax, miliaria, pinorum, pseudo- puma, taeniopus, and versicolor groups). The connection is tendinous in Acris, Pternohyla, Triprion, Phyllomedusa lemur, some Agalych- nis and Ptychohyla, and in the other species groups of Hyla. In most Middle American hylids, the anterior ramus of the pterygoid articulates with the maxillary at a level near the posterior edge of the orbit, but in some kinds the articulation is at the level of the middle or anterior part of the orbit. The latter condition is typical of Acris, Pseudacris, Hemiphractus, Plectrohyla avia, Pternohyla dentata, members of the Hyla eximia and versicolor groups, plus Hyla angustilineata, miliaria, pentheter, pinorum, and siopela. Quadratojugal: Small paired bones in the posterior part of the upper jaw. In a fully developed condition the quadratojugal articu- lates anteriorly with the maxillary; posteriorly the ossification of the quadratojugal invades the cartilage of the quadrate process. Three conditions of the quadratojugal are evident — present and articulating with the maxillary, reduced and not articulating with the maxil- lary, and absent. The quadratojugal is absent in the Hyla pictipes and sumichrasti groups, plus Hyla bromeliacia, melanomma, and ze- teki. It is reduced or absent in Ptychohyla, Plectrohyla, and the Hyla bistincta and haze- lae groups. The quadratojugal is reduced in the Hyla leucophyllata, microcephala, mixo- macidata, rivularis, and parviceps groups, plus Hyla arborescandens and rufioculis. In all other species of Hyla and in the Middle American genera, other than Ptychohyla and Plectrohyla, the quadratojugal articulates with the maxillary. Squamosal: Paired, triradiate bones at the posterolateral corners of the skull. The posterior arm and the proximal part of the anterior arm usually articulate with the crista parotica of the prootic, the ventral arm articu- lates with the quadrate process of the upper jaw. The squamosal lacks a bony articula- tion with the crista parotica in Acris, Pseuda- cris, Anotheca, Plectrohyla ixil and matudai, Ptychohyla spinipollex, and in several species groups of Hyla (bistincta, bromeliacia, exi- mia, godmani, leucophyllata, microcephala, picta, salvadorensis, and versicolor groups). In Pternoliyla fodiens and Triprion petasatus, the squamosal lacks a bony connection with the crista parotica; instead the squamosal is in broad articulation with the frontoparietal, which is greatly expanded posteriorly and laterally so as to cover the crista parotica. In most hylids, the anterior arm of the squa- mosal extends anteroventrally from its base for about one-third to one-half of the distance to the maxillary; in these frogs, a tendon con- nects the anterior arm of the squamosal to the maxillary. In some species in which there is a great proliferation of bone, the anterior arm of the squamosal is in bony contact with the maxillary, thereby forming a complete arch. This condition obtains in eight species of Middle American hylids: Gastrotheca cerato- phrys, Hemiphractus panamensis, Pternohyla dentata and fodiens, Smilisca baudinii and pliaeota, Triprion petasatus and spatulatus. Endochondral Elements Columella: The cartilaginous and bony rod connecting the tympanum with the inner ear. The only variation noted is that in some species, the columella is expanded distally, whereas in most species, it is of nearly uni- form diameter throughout the distal half of its length. Crista Parotica: The dorsal part of the prootic overlying the columella and extending from the braincase laterally to the squamosal. The major taxonomic feature of the crista parotica is the nature of its connection with the squamosal; this relationship has been discussed under the squamosal. Exoccipital: A bone forming the posterior end of the braincase posterior to the prootic and around the foramen magnum. In adults, it is fused with the prootic. No variations of taxonomic importance have been noted. Meckel's Cartilage: The cartilaginous rod of the lower jaw lying medial to the dentary anteriorly and lateral and dorsal to the angu- Iosplenial posteriorly. The cartilage articu- lates with the cartilaginous quadrate process in the articular region. Mentomeckelian: Paired small elements in the lower jaw lateral to the mandibular symphysis and articulating with the dentary laterally. Prootic: The median bone forming the otic capsules and the braincase posterior to 1970 DUELLMAN: HYLID FROGS 49 the sphenethmoid and completely fused with the exoccipital in adults. In some species, the prootic is synosteotically united with the sphenethmoid (see discussion under that element).- The nature of the articulation be- tween the median ramus of the pterygoid and the prootic have not been studied thoroughly, even though interspecific differences of po- tential taxonomic importance probably exist. Comparison of the figures of skulls in the fol- lowing descriptions of genera and species groups demonstrates differences in the mas- siveness and width of the otic regions. Quadrate Process: The cartilaginous proc- ess of the articular region articulating with the quadratojugal, ventral arm of the squa- mosal, posterior ramus of the pterygoid, and Meckel's cartilage. This process can be stud- ied adequately only in serial sections; conse- quently, it has not been utilized in the taxo- nomic analysis of characters. Septomaxillary: Small paired bones lying within the olfactory capsule and possibly of dermal origin. The septomaxillaries are lost in most dried skeletons and appear as free elements in the illustrations of cleared and stained skulls. Trueb (1970a) noted the ex- istence of two architectural types of septo- maxillaries. Among the few Middle American species in which this character has been studied, Phrynohyas has one type, whereas a second type occurs in Smilisca baudinii, Pter- nolnjla dentata and fodiens, and Triprion petasatus and spatulatus. Septum Nasi: The cartilaginous partition between the olfactory capsules. The septum is synchondrotically united with the sphen- ethmoid posteriorly. In some of those species in which the anterior part of the spheneth- moid is ossified anteriorly, the septum nasi is partly ossified and synosteotically united with the sphenethmoid. This condition is present in Gastrotlieca, Hemiphractus, Plec- trohyla, Pternohyla, Triprion, some Ptycho- hyla, and a variety of stream-breeding Hyla, including at least some members of the haze- lae, miotympanum, mixomacidata, pseudo- puma, rivularis, taeniopus, and zeteki groups. " Synosteosis is ossification from two or more cen- ters in the same bone; synchondrosis is the union of two or more elements by cartilage. A synosteotic unification also is present in Hyla valancifer and the Hyla boans group. Sphenethmoid: A median endochondral bone forming the anterior end of the brain- case and usually articulating posteriorly with the prootic. The major variation in the sphenethmoid is in the amount of ossification. The sphenethmoid is poorly ossified anteriorly and posteriorly in Acris and posteriorly only in Pseudacris. The synosteotic relationships of the sphenethmoid anteriorly with the sep- tum nasi have been discussed under the sep- tum nasi. In three of the species (Hemiphrac- tus panamensis, Hyla boans, and Plectrohyla guatemalensis) having synosteotic unification of the sphenethmoid and the septum nasi the sphenethmoid also is synosteotically united with the prootic posteriorly. The same rela- tionship posteriorly is present in Phyllome- dusa venusta, which does not have synosteotic unification between the sphenethmoid and the septum nasi. In all other species, the sphenethmoid is synchondrotically united with the prootic. Other kinds of variation in the sphenethmoid include the shape, as viewed from the dorsum, of the anterior ossi- fied part. In some groups, the anterior end is broadly truncate and terminates posterior to the nasals; in others it extends anteriorly between or below the nasals and terminates in an acute tip, notched tip, or truncate end. The relationships between the sphenethmoid and nasals were discussed under the latter structure. Dermal Modifications Various modifications of the dermal ele- ments occur in hylid frogs; these usually in- volve and accompany proliferation or expan- sion of the roofing bones. In most species having a great amount of proliferation of bone, the dermal elements are usually com- pletely or partly involved in integumentary- cranial co-ossification. According to Trueb (1966, p. 572) integumentary-cranial co-ossi- fication involves the deposition of bone in the connective tissue of the lower dermis of the skin. In some species, the co-ossified skull is expanded so as to form a cranial helmet; these are the so-called casque-headed hylids. In Middle America Pternohyla and especially Triprion have highly modified easqued heads; 50 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 in one species in each of those genera a der- mal sphenethmoid is present and involved in co-ossifieation. The bizarre head of Anotheca spinosa consists of a skull having many spiny protuberances from the dermal roofing bones, which are co-ossified with the overlying skin. The skull of Gastrotheca nicefori is not greatly expanded, but the dermal roofing bones are co-ossified with the skin, and the frontoparie- tals and squamosals are co-ossified in Hyla fimbrimembra. In Hemiphractus, the dermal roofing bones are exostosed and greatly expanded so as to form a triangular helmet, but the skin is not co-ossified with the skull. This most bizarre skull in the hylids is described in detail in the generic account of Hemiphractus. The dermal bones of the skull of Gastrotheca ce- ratophrys are expanded and weakly exostosed but not co-ossified. Osteoderms are present in Hyla miliaria and Phyllomedusa venusta; in the former they are closely compacted on the head. The skin on the top of the head is immovable, but it is not co-ossified with the roofing bones. The osteoderms make the skin rigid. Dentition In all Middle American hylids, teeth are present on the maxillaries and premaxillaries and with the exception of Hemiphractus and some small species of Hyla (picta, and some specimens of smaragdina, smithii, and sumi- chrasti), teeth are present on the prevomers. Odontoids are present on the dentary and prevomer in Hemiphractus and on the para- sphenoid in Triprion; these are bony projec- tions and in no way should be confused with the occurrence of true teeth. In most Middle American hylids, the teeth are spatulate and bifid, or even weakly trifid, but in some of the small species, for example those in the Hyla leucophyllata and micro- cephala groups, the teeth are simple and conical. In some species of Plectrohyla, not- ably avia, the teeth are long and pointed. The numbers of maxillary and premaxillary teeth have not been determined except in Plectrohyla, a genus in which the number of teeth has customarily been used as a taxo- nomic character. This negligent dismissal of the number of teeth was done with full knowl- edge of Goin's ( 1958 ) suggestion of the taxo- nomic importance of the number of teeth. My only excuse is that I was simply too lazy to count all of those minute teeth. However, in the best of herpetological tradition, I did count the number of prevomerine teeth. These data are summarized in Table 3 and show that in general, larger species have more teeth than smaller ones and that larger species in a given species group have more prevomerine teeth than do the smaller species in that group. Further evidence that the number of prevomerine teeth is directly related to the size of the frog is provided by the fact that females of a given species are larger than the males and have on the average more pre- vomerine teeth. Chromosomes Testes were obtained from frogs immedi- ately after they had been drowned in a chloro- butanol "chloretone" solution, and the testes were fixed in a solution composed of 100 per cent methanol, 95 per cent ethanol, ace- tone, chloroform, and 100 per cent proprionic acid, in a ratio by volume of 2:4:1:2:1, re- spectively. Testicular tissue was squashed and stained with a propriono-orcein stain ( see Ducllman and Cole, 1965, and Duellman, 1967b, for techniques). Chromosome num- bers can be determined by the use of testicu- lar tissue prepared in this matter, but for an analysis of karyotypes, an injection of colchi- cine into the body cavity prior to killing is necessary ( see Cole, 1966, for details ) . Hylid frogs are known to have haploid numbers of 11 to 15 chromosomes and diploid numbers of 22 to 30 chromosomes ( Duellman, 1967b). The entire range of numbers occurs in the 48 species of Middle American hylids for which data are available (table 4). Inso- far as known, the genera Anotheca, Plectro- hyla, Pternohyla, Ptychohyla, Smilisca, and Triprion have a haploid number of 12 chromo- somes. Agalychnis, Pachymedusa, and Phyl- lomedusa have 13, whereas Acris has 11, and Gastrotheca has 14. Most Middle American species of Hyla have a haploid number of 12 chromosomes, but some have 15. The data on chromosome numbers is ex- tremely scanty, but even the meager informa- tion available presents some interesting points. 1970 DUELLMAN: HYLID FROGS 51 TABLE 3 Total Number of Prevomerine Teeth in Middle American Hylicl Frogs. (Means in Parentheses after Observed Ranges) Males Females Species N Teeth N Teeth Acris crepitans Agalychnis annae _ ._ Agalychnis calcarifer Agalychnis callidryas Agalychnis litodryas Agalychnis moreletii ... Agalychnis saltator _ Agalychnis spurrelli ___ Anotheca spinosa ___ Gastrotheca ceratophrys Gastrotheca nicefori Hemiphractus panamensis Hyla altipotens Hyla angustilineata Hyla arhorescandens Hyla arenicolor Hyla bistincta Hyla Loans Hyla bogertae Hyla houlengeri Hyla bromeliacia _ Hyla cadaverina Hyla chaneque Hyla charadricola Hyla chryses Hyla colymha Hyla crassa Hyla crepitans Hyla debilis Hyla dendroscarta Hyla ebraccata Hyla echinata Hyla elaeochroa Hyla erythromma Hyla euphorbiacea Hyla eximia Hyla fimbrimembra Hyla godmani Hyla hazelae Hyla lancasteri Hyla legleri Hyla loquax Hyla melanomma Hyla microcephala Hyla miliaria Hyla miotympanum 10 4- 8 (6.4) 5 4- 8 (6.8) 35 10-14 (12.0) 5 17-23 (20.2) 2 9-10 (9.5) 1 11 26 8-11 (9.7) 7 12-16 (14.0) 1 20 0 25 10-13 (11.2) 6 12-16 (14.2) 10 7-10 (8.6) 5 9-12 (10.6) 15 14-17 (15.3) 3 16-18 (17.0) 20 10-19 (12.6) 8 12-19 (12.5) 4 14-18 (16.3) 1 17 3 13-16 (14.3) 0 11 5 5 13-18 (15.0) 2 10-12 (11.0) 12 6-10 (8.3) 3 9-10 (9.3) 23 8-14 (10.8) 4 10-16 (12.6) 22 9-12 (10.4) 3 10-13 (11.4) 19 6-14 (9.8) 2 10-13 (11.5) 10 39-53 (48.3) 2 47-52 (49.5) 1 6 1 9 25 8-17 (13.0) 8 12-19 (15.2) 6 6- 8 (6.4) 2 6- 8 (7.0) 16 4- 7 (6.1) 9 4- 8 (6.4) 25 9-16 (12.6) 6 12-18 (15.2) 10 5-10 (7.6) 3 8-10 (9.0) 3 3- 5 (4.3) 1 7 6 11-15 (13.0) 3 11-15 (13.3) 1 10 1 15 19 20-24 (22.3) 5 25-28 (26.4) 9 4- 6 (5.1) 5 6 10 6-10 (6.6) 1 8 25 0- 5 (2.8) 6 4- 7 (5.7) 1 14 1 14 101 3-14 (9.9) 15 9-15 (11.8) 25 8-14 (10.2) 4 14-18 (16.2) 25 5- 9 (7.8) 5 6-10 (8.1) 25 6-10 (8.1) 3 6-11 (8.5) 0 1 16 25 8-12 (10.2) 4 7-11 (9.3) 7 8-10 (8.9) 0 23 6- 9 (7.5) 2 12-14 (13.0) 18 6- 8 (7.2) 3 8-10 (9.4) 25 8-12 (10.3) 4 8-12 (10.0) 19 6- 9 (7.2) 3 6-10 (8.0) 25 4- 7 (6.1) 8 4- 8 (6.3) 4 19-33 (23.8) 1 20 20 5-11 (8.2) 5 8-14 (10.4) 52 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TABLE 3— (Continued) Males Females Species N Teeth N Teeth Hijla tnixe 0 .... 2 5- 6 (5.5) Hyla mixomaculata 3 6-10 (8.2) 2 8-11 (9.5) Hyla nubicola 3 6- 8 (7.0) 1 8 Hyla pachyderma 16 2 8 Hyla pellita 3 6- 8 (7.0) 2 7-10 (8.5) Hyla pentheter 7 7-11 (8.7) 2 13-15 (14.0) Hyla phlebodes 25 4- 9 (7.2) 6 5-10 (7.9) Hyla picadoi 5 4- 6 (5.3) 1 9 Hyla picta 25 0 5 0 Hyla pictipes 25 6-12 (9.0) 6 11-15(12.7) Hyla pinorum 5 6- 8 (6.8) 1 8 Hyla plicata 15 8-12(10.3) 5 10-14(11.8) Hyla pseudopuma 30 8-12 (9.6) 11 10-14 (11.6) Hyla regilla 34 6-11 (7.3) 7 8-12 (10.3) Hyla rivularis 25 4- 8 (7.1) 6 9-12 (10.8) Hyla robertmertensi _ 25 4- 6 (5.1) 5 4- 6 (5.5) Hyla robertsorum 24 4- 7 (6.0) 5 5- 9 (7.0) Hyla rosenbergi 18 29-33 (31.0) 7 32-35 (33.8) Hyla rostrata ..-.. 28 9-15 (11.2) 1 12 Hyla rubra 17 9-12(10.6) 4 13-16(14.2) Hyla rufioculis 25 4-10 (6.0) 6 7-9 (8.0) Hyla rufitela 25 18-23(21.3) 2 21-23(22.0) Hyla salvadorensis 6 6-10 (8.6) 0 Hyla sartori 25 6- 8 (7.3) 6 6-8 (7.5) Hylasiopela 7 6- 9 (7.9) 5 8-9 (8.4) Hyla smaragdina 25 2- 6 (3.8) 1 5 Hyla smithii 25 4- 6 (5.1) 6 5-7 (6.0) Hyla staufferi 29 5-11 (7.8) 7 6-11 (8.9) Hyla subocularis 25 4- 6 (4.8) 6 5-9 (6.4) Hyla sumichrasti 23 0-5 (0.9) 17 0-6 (1.1) Hyla taeniopus 18 9-16 (12.7) 8 9-16 (13.3) Hyla thorectes 20 6-11 (8.3) 2 10-15(12.5) Hyla thysanota 0 1 21 Hyla tica 21 7-11 (9.0) 6 13-14(13.3) Hyla uranochroa 21 6-12 (9.6) 12 8-14(10.2) Hyla vahncifer 1 18 1 15 Hyla walked 20 6-11 (8.2) 3 6-12 (8.7) Hyla xanthosticta 0 — . 1 10 Hyla zeteki .... 3 6-8 (7.0) 6 7-9 (8.0) Pachymedusa dacnicolor 20 6-11 (8.8) 3 10-12(11.0) Phrynohyas venulosa _. 23 10-24 (15.7) 4 10-27 (17.2) Phyllomedusa lemur 20 0 2 0 Phyllomedusa venusta 3 10 1 7 Plectrohyla avia 4 2- 6 (4.1) 0 Plectrohyla glandulosa 12 2-6 (4.1) 5 2-6 (4.3) Plectrohyla guaternalensis .. 6 6-10 (7.8) 5 8-12 (9.9) Plectrohyla hartwegi 3 8-10 (9.0) 0 Plectrohyla ixil 22 6-10 (7.7) 4 7-10 (8.6) 1970 DUELLMAN: HYLID FROGS 53 TABLE 3— (Continued) Species N Plectrolnjla lacertosa 1 Plectrohyla matudai 8 Plectrolnjla pycnochila 2 Plectrohyla quecchi 8 Plectrohyla sagorum 15 Pseudacris clarkii 2 Ptcrnohyla dentata 25 Ptemohyla fodiens 20 Ptychohyla euthysanota 22 Ptychohyla ignicolor 38 Ptychohyla leonhardschultzei . 20 Ptychohyla schmidtorum 65 Ptychohyla spinipollex 32 Smilisca haudinii _ 25 Smilisca cyanosticta 23 Smilisca phaeota 10 Smilisca puma 10 Smilisca sila .. 10 Smilisca sordida 10 Triprion petasatus 20 Triprion spatulatus 53 Males Teeth N Females Teeth 5 0 6-10 (7.4) 3 7-10 (8.3) 6- 9 (7.5) 0 6- 8 (7.0) 1 8 6- 8 (6.9) 4 6- 8 (7.2) 4 0 8-12 (10.3) 3 10-12 (10.6) 8-12 (10.3) 4 11-13 (12.1) 0- 6 (4.5) 20 6-18 (9.5) 3- 9 (6.1) 7 4-10 (7.3) 6- 9 (6.5) 8 7-12 (9.5) 4-11 (5.3) 13 4-11 (7.9) 3- 7 (4.9) 6 6-10 (7.6) 10-17 (14.4) 7 11-18 (15.3) 7-21 (13.9) 3 14-22 (17.3) 9-17 (14.0) 10 10-18 (14.6) 8-14 (10.3) 5 9-15 (11.4) 9-13 (10.4) 10 10-14 (11.1) 8-11 (10.0) 7 S-12 (10.6) 8-15 (11.6) 10 14-20 (16.1) 10-15 (12.0) 20 10-16 (13.2) For example, the species of Hyla having a haploid number of 15 chromosomes are mem- bers of the leucophyllata, microcephala, and parviceps groups. These three South Ameri- can groups seem to be closely related on the basis of morphology, tadpoles, and habits. The only other hylid known to have 15 chro- mosomes is the Papuan Hyla angiana. Frogs in the phyllomedusine genera Agalychnis, Pachymedusa, and Phyllomedusa are unique among New World hylids by having 13 chro- mosomes; this number occurs in Australo- Papuan Hyla and Nyctimystes. Acris is the only hylid known to have 11 chromosomes, and Gastrotheca is the only one known to have 14. Voice The advent of high-quality portable tape recorders and sound analyzing equipment within recent years has opened a new field of investigation — bioacoustics. The usefulness of the characteristics of the voice in the taxon- omy of frogs has been demonstrated ade- quately by many workers [see especially Blair (1963b), Bogert (1960), Duellman (1963c), Duellman and Fouquette (1968), Duellman and Trueb (1966), and Fouquette (1960a)]. The importance of the mating call as an etho- logical isolating mechanism has been pointed out by several investigators [for recent sum- maries see Blair (1964), Duellman (1967c), Fouquette (1960b), Littlejohn and Michaud (1959), and Martof and Thompson (1958)]. Kinds of Anuran Calls Bogert (1960) provided a tentative classi- fication of anuran sounds and thoroughly documented an exhaustive discussion of the kinds of sounds with reference to the biologi- cal situations under which the sounds are produced. The following categories of his classification are applicable to Middle Ameri- can hylids: Mating Call: The call of the male frog in breeding condition is the most frequently heard and studied kind of call; furthermore, it is this call that is biologically significant as an isolating mechanism. Most species of Mid- dle American hylids produce a mating call; the calls of 76 species are described in the accounts of the species and illustrated on 54 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TABLE 4 Number of Chromosomes in Middle American Hylids. Species Haploid Acris crepitans 11 Agalychnis calcarifer 13 Agalychnis callidryas 13 Anoiheca coronata 12 Gastrotheca ceratophrys —.. . 14 Hyla arborescandens* .... - 12 Hyla arenicolor 12 Hyla boulengeri 12 Hyla chaneque 12 Hyla crepitans ... __ 12 Hyla ebraccata 15 Hyla elaeochroa 12 Hyla erythromma 12 Hyla euphorbiacea 12 Hyla eximia 12 Hyla legleri 12 Hyla loquax .. 12 Hyla microcephala 15 Hyla pentheterb 12 Hyla phlebodes 15 Hyla pictipes 12 Hyla plicata'' 12 Hyla pseudopuma .. 12 Hyla rivularis .... _ 12 Hyla robertsorum ..... . 12 Hyla rufiocidis 12 Hyla rufitela .. . 12 Hyla smaragdina 12 Hyla smiihii 12 Hyla staufferi .. 12 Hyla subocidaris . 15 Hyla tica 12 Pachymedusa dacnicolor 13 Phyllomedusa lemur 13 Phyllomedusa venusta .. 13 Plectrohyla ixil 12 Plectrohyla sagorum . . 12 Pternohyla fodiens 12 Ptychohyla ignicolor 12 Ptychohyla leonhardsclndtzei 12 Smilisca baudinii .... 12 Smilisca cyanosticta 12 Smilisca phaeota ..... 12 Smilisca puma 12 Smilisca sila .. 12 Smilisca sordida . 12 Triprion petasatus . 12 Diploid TABLE 4— (Concluded) Species Haploid Diploid Triprion spatulatus 12 24 22 26 24 24 24 24 24 24 24 24 24 " Reported as Hyla hazelae by Duellman and Cole (1965, p. 141). 6 Reported as Hyla bistincta by Duellman and Cole (1965, p. 141). '' Reported as Hyla lafrentzi by Duellman and Cole (1965, p. 141). plates 12-39. The males of some species of Hyla and Plectrohyla are mute; vocal slits and a vocal sac are absent. The calls of certain other species, which have vocal slits and a vocal sac, and presumably a mating call, are unknown. Release Call: The sounds emitted by a male when indiscriminately clasped by another male seemingly are produced by accentuated respiratory movements. Bogert ( 1960, p. 176 ) noted that the vibrations on the flanks may be more important than the sounds in eliciting the release of the clasped individual. Release calls are emitted by some males when grasped between the collector's thumb and forefinger. Usually the release call is shorter, more regularly spaced, and pitched at a lower frequency than the mating call of the same species (see plates 37 and 40). Bogert (1960, p. 181) described a re- lease call produced by an unreceptive female Pachymedusa dacnicolor when clasped by a male. Charles Myers (1966) noted short grunts produced by several Hemiphractus panamensis contained in a back-pack when jostled along a mountain trail; the mating call is not known in this species. Some au- thors have used the term "warning call" for the calls classified here and by Bogert ( 1960 ) as release calls. Territorial Call: No documented cases of territorial calls are known in hylids, although Greenberg ( 1942 ) suggested that the call and pulsating dark throat serve a territorial func- tion in Acris crepitans. Many Middle Ameri- can hylids produce single, often widely spaced notes that essentially are like the note or first of a series of notes in the mating call. These calls, which are known in Hyla ebraccata, H. elaeochroa, H. rosenbergi, Smilisca baudinii, and Agalychnis callidryas, possibly have a territorial function, especially in Hyla rosen- 1970 DUELLMAN: HYLID FROGS 55 bergi, which emits these calls from high in trees and the normal mating call in shallowly dug basins in swamps or edges of streams. The round of clucking from high in the trees by Agalychnis callidryas at dusk might be of territorial significance (see account of that species for details). However, in each of these species, the territorial function is in- ferred but not demonstrated through obser- vation or experimentation. Rain Call: The calls emitted by male frogs at areas away from breeding sites are loosely grouped in this category. Usually the notes are radically different from the mating call and frequently these notes are uttered just before or during diurnal showers. For ex- ample, the mating call ot Agalychnis callid- ryas consists of a single, or sometimes double, note — "chock" repeated at intervals of ten seconds to more than a minute, whereas the rain call consists of a series of short notes, "cluck-cluck-cluck," repeated at intervals of about 0.1 of a second (pi. 30). The rain call of Hyla eximia also consists of a series of short notes and is produced by individuals in trees or in bromeliads, whereas the mating call is given only in, or at the edge of, grassy ponds. In those species that have a mating call composed of a single primary note fol- lowed by a series of secondary notes and for which a rain call is known, the rain call con- sists of a single note sounding much like a short primary note. This is the kind of rain call produced by Hyla ebraccata, microceph- ala, and phlebodes. The rain calls of Hyla elaeochroa and stanfferi are abbreviated ver- sions of a single note in the mating call. I am unaware of rain calls in any of the stream- breeding inhabitants of cloud forests; how- ever, the calling of Plectrohyla sagorum from bromeliads by day reported by Taylor and Smith (1945, p. 597) might be so designated, although those authors did not mention dif- ferences between those calls and the calls produced by males along streams at night. The function of the rain call is unknown, although Blair (1958) and Bogert (1960) suggested that these calls in some Hyla in southeastern United States and in Mexico might have a territorial function. Distress Call: Bogert (1960, p. 203) used the term distress call for those calls emitted, usually with the mouth open, when a frog has been seized by a predator. Such calls are well-known in Rana and some leptodactylids, and the piercing squall of a Leptodactylus pentadactylus held tightly in the hand is legendary among collectors in the American tropics. There have been few reports of dis- tress calls in Hyla. Dickerson (1906) men- tioned cries of both sexes in Hyla arenicolor; Lankes (1928) reported outbursts in the Aus- tralian Hyla caeridea, and Duellman and Trueb ( 1966 ) noted that a female Smilisca baudinii emitted a distress call when picked up. Social Organization in Mating Calls The social organization in the mating calls seems to have some systematic, as well as ecological importance. Duellman (1967a) re- ported on social organization in several Neo- tropical hylids and proposed a classification of social organization in mating calls. The major categories in the classification are: In- dividual, Non-aggregate, and Aggregate. In the first category are those species in which there is no aggregation of individuals when calling and no social organization of the calls. Anotheca spinosa, Gastrotheca cera- tophrys, and G. nicefori seemingly belong in this category. In the former, the eggs are laid in water-filled cavities in trees, whereas in the latter, the eggs are carried by the females. Limited observations on bromeliad-breeders, such as Hyla bromeliacia, indicate that there is no breeding aggregation and suggest that there is no organization of calls. Other bro- meliad-breeders, such as Hyla dendroscarta, zeteki, and possibly picadoi, also might be- long in this category. In the non-aggregate category are those species that have no aggregation of individ- uals when calling, but the calls of two or more individuals are organized into duets, trios, or some other sequence. Although this kind of organization is not uncommon in the terrestrial-egg laying Eleutherodactylus in humid lowland and montane forests, I can- not definitely assign any Middle American hylids to this category. Perhaps some, or all, of the bromeliad-breeding species of Hyla mentioned above belong in this category, but at this time observations on their mating calls 56 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 are too fragmentary to determine the presence of organization. The great majority of Middle American hylids belong in the aggregate category, those species in which individuals congregate at breeding sites and have the calls organized or not. From the limited observations, it has not been possible to demonstrate organiza- tion in the mating calls of most of the species, especially the stream-breeders. However, or- ganization is well-developed in the calls of some species, and this organization is one of two basic kinds — completely organized and initially organized. Duellman (1967a, p. 159) described in detail the organization of duets in choruses of Smilisca baudinii and of duets, trios, or quartets in Smilisca puma. In each of these observations, a dominant individual initiated each successive chorus. A loose or- ganization seems to exist in the calls of the stream-breeding Smilisca sordida in which the call is emitted by one individual and picked up by successive individuals along the stream. It is unknown if the same individual initiates successive choruses. Initial organization is well documented only in Hyla claeochroa in which successive choruses of about 20 individuals were initiated by a definite calling sequence by the same three individuals, after which all individuals commenced calling and organization was no longer apparent (see Duellman, 1967a, p. 161) for details. Initial organization is indi- cated by limited observations on Hyla rosen- bergi. Terminology of Call Structure Although electronic recording and analy- sis of anuran calls have been utilized by sev- eral workers in the past 15 years, there is a remarkable dearth of detailed commentary on the terminology involved and on the in- terpretation and methods of measuring vari- ous parameters of the calls evident on the audiospectrograms. Rlair and Pettus (1954) and Rlair ( 1955 ) briefly described the use of a spectrographic analyzer, and Fouquette (1960a) and Duellman (1963a) discussed the terminology and techniques of measurement of anuran calls. Rorror (1960), Rroughton ( 1963 ) , and Andrieu ( 1963 ) described vari- ous general terminology and techniques in bioacoustical research. The methods of re- cording and analyzing the calls used by me is essentially the same as that employed by other workers, and these methods and kinds of equipment are discussed in a foregoing section on materials and methods. Here I am concerned with the terminology, techniques of measurement, and interpretation of the electrically inscribed marks on the audiospec- trogram. The lack of clear definitions of terms and explanation of techniques has had a pro- found effect of confusing and discouraging novices in this field of research. The call or call-group is the entire assem- blage of sound units produced in a given sequence. In many species, the call consists of a single note, such as in most species of Agalychnis, Phnjnohyas, and many species of Hyla, especially the stream-breeding species. In some species, the single note is a long well-pulsed trill; this kind of call is charac- teristic of Triprion spatulatus and members of the Ptychohyla euthysanota group. Most species have calls consisting of more than one note. The notes per call-group vary from two or three in many species to several score in frogs such as Hyla eximia and staufferi. The call rate is the measure of the rate of production of call-groups and is measured in calls per minute. In those species in which there are two or more notes in the call, the rate in time that notes are produced is called the note repetition rate and is given in the number of notes per minute. In most species, the number of notes can be counted actually during the call or from a recording and the lapsed time measured by means of a stop watch. In those species having extremely short and quickly repeated notes, such as the secondary notes in the Hyla microcephala group, it is neces- sary to measure the time on an audiospectro- gram. A note is any given individual unit of sound, whether the short peep of a centrolenid or the long trill of a toad. On an audiospec- trogram, the note is a continuous, or nearly so, darkened area. A note that is continuous and lacks an intermittent pause is said to be monophasic, whereas a note having an inter- mittent depression in intensity or brief pause is classified as diphasic (fig. 20A). The mono- 1970 DUELLMAN: HYLID FROGS 57 mmary Secondaries Monophasic Diphasic :££tr,:. :o?*?: W SI fe-ik Modulation Good .s****"*5toitaii.''-. . . >-;>»i-»0.«;ASrt'*l**aW;j_ ' Poor litis Trass Jf* Tril •1 i ^•>.- -'-'-y-.r.;L.Y..J .^'-/%, I' A..--5F -.1 ••:■;(: -..:^ 1 >i ••-•.•J ,.:.- - I •i:i» if h* i I i Puis MiHriMW^t ■ Pulses u Harmonics Dominant Frequency ' 1 ' ■ i i ■ Duration( in Seconds) > Fig. 20. Diagrammatic representations of sounds as seen on audiospectrograms and sections. A. Kinds of notes. B. Modulation and pulsation. C. Terminology of audio characters. 58 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 phasic versus diphasic condition of notes seems to be constant within a species and is a useful criterion in characterizing calls (see audiospectrograms of calls of members of the Htjla microcephala group on plates 28 and 29). Some species of frogs produce two kinds of notes that differ in duration (length of note, measured in seconds or parts thereof) and structure (monophasic or diphasic). In most of these species, a long note is followed by one or more shorter notes. In such cases, the long note is called the primary note and the short notes are called secondary notes (fig. 20A). Secondary notes are classified as such only when they are preceded by a pri- mary note. This kind of call is characteristic of members of the Hyla leucophyllata and microcephala groups. Hyla melanomma pro- duces long and short notes (pi. 17), but these are irregularly arranged and consequently do not qualify as primaries and secondaries. Each note has a definite range of frequency (pitch) expressed in cycles per second ( cps ) or Hertz (htz). In some species, the lowest frequencies approach zero and sounds are produced throughout the frequency spectrum to about 8,000 cycles per second, or even more. In other species, the frequency range is much restricted, usually to the lower fre- quencies, but in some (Hyla debilis, for ex- ample) the frequency range is narrow but high. The distribution of the sound (energy) through the frequency spectrum (vertical on audiospectrogram ) is a useful systematic character. The distribution of sound is re- ferred to as modulation. In a well-modulated note, the energy is concentrated into a num- ber of narrow bands of frequency (called harmonics and appearing as distinct horizon- tal lines on audiospectrogram). Opposed to this melodious type of note is the noisy note, in which the sound is spread throughout the frequency spectrum without distinct concen- trations as individually defined harmonics (fig. 20B). In the time span of a note, dis- tinct pulsations of sound usually are notice- able; these appear as vertical marks or verti- cal rows of dots on the audiospectrograms. The pulses can be counted in given notes and in successive notes in order to arrive at the pulse rate, the rate at which pulses are pro- duced. This is given in the number of pulses per second. In some anurans the notes are long and composed of many distinct pulses that are audible to the human ear (fig. 20B); such notes are usually referred to as trills. Toads of the genus Bnfo characteristically have a trill. This kind of call is not common in hylids; it is best developed in Triprion spatulatus and in members of the Ptycliohyla cutliysanota group (see plates 31 and 34). In some species, particularly some Agalychnis, the last one or two pulses in each note are emphasized in intensity. Various measurements of two parameters of the frequencies of the notes are commonly utilized in studies of anuran calls. The most useful measurements are those of the domi- nant and fundamental frequencies, both mea- sured in cycles per second (Hertz). The sound emanating from a frog has a spectrum of frequency. In well-modulated notes, the spectrum is divided into distinct harmonics, which arc masked, but nevertheless present in poorly modulated notes. That frequency of sound resulting from the air passing over the vocal cords and causing them to vibrate at a frequency primarily dependent on the tension of the vocal cords is the basic (lowest pitched) harmonic and is usually referred to as the fundamental frequency. Each suc- ceedingly higher harmonic is a multiple of the basic harmonic. If the fundamental fre- quency is rather high and is not partially masked, it can be measured directly on the audiospectrogram or section, which is a visual measurement of the relative intensities of the sound throughout the frequency spectrum (fig. 20C). Otherwise, the fundamental fre- quency can be determined by measuring the distance between several successive adjacent harmonics and dividing the total measure- ment by the number of harmonics measured. The frequency of sound resulting from the resonating of the fundamental frequencies or one of its harmonies with greater emphasis than any other frequency is called the domi- nant frequency. The area of the dominant frequency is the darkest part of the note on the audiospectrogram and is the longest (ex- tended farthest to the left) part on the sec- tion (fig. 20C). The dominant frequency usually can be measured with ease directly from the audiospectrogram and more aceu- 1970 DUELLMAN: HYLID FROGS 59 rately from the section. Otherwise, the dom- inant frequency can be determined by count- ing the number of harmonics up to the dominant harmonic and multiplying this number times the fundamental frequency. Acoustically speaking, the dominant fre- quency is always a multiple of the fundamen- tal frequency, but sufficiently accurate mea- surement on a scale of 8,800 cycles in a distance of about 100 mm. is not possible. Consequently, the second method is the man- ner by which to most accurately measure the dominant frequency in most cases. In some species, for example Smilisca baudinii, two harmonics are emphasized with nearly the same intensity; in such cases the term domi- nant frequency has been discarded, and the two emphasized harmonics are called major frequencies. The fundamental frequency, which is de- pendent upon the structure and tension of the vocal cords is usually less variable within a given species than is the dominant fre- quency, which is an expression of the resonat- ing chamber. The vocal sac (resonating cham- ber) is inflated to various degrees. A par- tially inflated sac will result in a different dominant frequency than a fully inflated sac. Observations and concommitant recording of certain individuals have resulted in the cor- relation of a notably lower dominant fre- quency of a given note with the partial inflation of the vocal sac at the time of the production of that particular note. In well- modulated notes, the harmonics can be counted easily. In these notes it is useful to determine which harmonic is the dominant frequency; the lowest harmonic ( fundamental frequency) is counted as number one. A shift upward or downward of one harmonic in the dominant frequency results in consid- erable variation in the dominant frequency as compared with the fundamental frequency. For example, in a series of recordings of 10 individuals, let us assume that the funda- mental frequency varies from 110 to 125 cycles per second. If the dominant frequency is the eighth harmonic, the range of the dom- inant frequency will vary from 880 to 1000 cycles per second. A shift of one harmonic upward and downward to the dominant fre- quency in this series would result in a poten- tial frequency range of the dominant fre- quency from 770 to 1125 cycles per second. This actual and potential variation not with- standing, the position of the dominant fre- quency still is one of the most important characteristics of the anuran call in systematic studies. The intensity or loudness of the calls has not been measured. Such measurement is possible by using a sound-level meter at a standard distance from a calling individual. An attempt was made to gather data on in- tensities in the early part of this study, but was soon abandoned as being impractical in the field. Accurate measurement with a sound-level meter can be obtained only if one frog is calling. Seldom is this the case in the field, for several individuals, if not several species, usually are calling simul- taneously. Thus, the sound-level meter mea- sures only the intensity of the sound emanat- ing from an entire chorus. Consequently, ob- jective electronic measurement was forsaken for the subjective human ear, with the result that two generalizations can be made about the loudness of hylid frogs. Larger frogs, such as Hijla boons, H. rosenbergi, H. loquax, Gas- trotheca ceratophrys, Smilisca baudinii, S. phaeota, and Phnjnohyas venulosa, usually have louder calls than do the smaller species. At least, their calls can be heard at a much greater distance than the calls of the smaller species, and in mixed choruses the calls of these species mask those of smaller species. This apparent loudness may be due partly to the lower frequencies that are emphasized in most of these large species. An exception is the relatively soft notes produced by frogs of the genera Agalychnis, Pachymedusa, and Phyllomedusa. The second generalization is that stream-breeders tend to have weaker voices than pond-breeders. In some stream- breeding species, such as members of the Hyla bistincta and mixomaculata groups and some species of Plectrohyh., the voice is ab- sent, whereas in Ptychohyla, some Plectro- hyhi, and members of the Hyla pinorum and sumichrasti groups the voice is soft. In some species, it is barely audible above the sound of flowing water. 60 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Effect of Temperature on Calls Bellis (1957), Zweifel (1959), Bogert (1960), and Duellman and Trueb (1966) have discussed the effect of temperature on various parameters of the calls of certain anurans. Bellis (1957) noted that in Pseuda- cris triseriata the note repetition rate in- creased and the duration of the notes de- creased with a rise in temperature. Zweifel ( 1959) analyzed recordings made at tempera- tures of 16.8° to 25.6° C. of a single Bombina oariegata and demonstrated that the repeti- tion rate and pitch are positively correlated with temperature, whereas the duration of the call is negatively correlated with tempera- ture. Bogert (1960, p. 299) reported on seven samples of recordings of Hyla eximia made at temperatures ranging from 15° to 20° C. at various localities on the Mexican Plateau and noted that the duration of the calls was longer at lower temperatures but that no direct correlation seemed to exist between pulse rate and temperature. Snyder and Jameson ( 1965 ) obtained high correlations between temperature and duration of notes and note repetition rate in Hyla regilla. Duellman and Trueb (1966, p. 355) noted that in the species of Smilisca there exists a positive correlation between pulse rate and temperature and between the level of the fundamental frequency and temperature, whereas no correlations were found between temperature and other parameters of the calls, such as duration and note repetition rate. During the course of the present study, few conclusive data were obtained on the effect of temperature on calls. This is due principally to the fact that most of the re- cordings of a given species were obtained within a relatively narrow span of tempera- ture. Two significant exceptions do exist — Hyla euphorbiacea and lancasteri. Seven in- dividuals of the latter species were recorded at temperatures of 21.7° to 22.0° C. and two were recorded at 16.7° C. Analyses of the audiospectrograms of these recordings showed a positive correlation of the note repetition rate, pulse rate, and level of the dominant frequency with temperature and a negative correlation between the duration of the note and temperature. Analysis of the recordings of 23 individuals of Hyla euphorbiacea at temperatures ranging from 12.5° to 21.5° C. shows a positive correlation of temperature with call rate, note repetition rate, pulse rate and levels of fundamental and dominant fre- quencies, but a distinct negative correlation between temperature and the duration of the notes; frogs recorded at 12.5° C. produced notes with a duration of 0.08 to 0.11 (mean, 0.098) of a second, whereas those recorded at 21.5° C. produced notes with a duration of 0.04 to 0.05 (mean, 0.047) of a second (see accounts of those species for details). On the basis of most observations, positive correlations between temperature and all parameters of the call, except duration of the notes, seem to exist; duration of the notes apparently is negatively correlated with tem- perature. My analysis of 34 recordings of Hyla eximia from 10 localities emphasizes Bogert's (1960, p. 299) concern that the variations in calls in that species when compared with the temperature at which the frogs were recorded did not exhibit the kinds of correlations noted by previous workers who had studied other species. The geographic mosaic of variation in calls in Hyla eximia points out the fact that many more recordings are needed and that perhaps we are dealing with two or more sibling species (see acount of Hyla eximia ) . Geographic Variation in Mating Calls Minor variation in certain parameters of the calls of given species are evident in re- cordings from distant localities. Such geo- graphic variation has been pointed out in Hyla staufferi by Leon (1968) and in Hyla microcephala, robertmertensi, and phlebodes by Duellman and Fouquette (1968). Geo- graphic variation in mating calls is evident in Hyla ebraccata, elaeochroa, loquax, mela- nomma, and uranochroa, and in Agalychnis callidryas (see accounts of these species). Notably because of the absence of large series of recordings of a given species from through- out its range, geographic variation in the mating call of frogs has been largely ignored. An outstanding exception is the sophisticated multivariate analysis of the calls of Hyla regilla provided by Snyder and Jameson 1970 DUELLMAN: HYLID FROGS 61 (1965), who unfortunately did not take into consideration the size of the individual frogs that were recorded. Future students of geo- graphic variation in the characteristics of calls are obligated to: 1) Record the temperature of the frog immediately after recording the call, 2) Preserve the recorded individual for positive identification and subsequent mea- surement, 3) Take into account temperature and size in the analysis of geographic varia- tion, and 4 ) Obtain large series of recordings so that the variation can be treated statisti- cally. The Mating Call as an Isolating Mechanism The isolating effects of the mating call in sympatric and synchronic breeding congre- gations have been discussed and substantiated by numerous authors working with a variety of frogs in North and Middle America, Aus- tralia, and South America (see Bogert, 1960, and Blair, 1964, for recent summaries). The mating call as an ethological isolating mech- anism has been studied in several Middle American hylids — Hijla eximia group by Blair (1960), Ptijchohyla by Duellman (1963c), Smilisca by Duellman and Trueb (1966), Hyla microcepliala group by Duellman and Fouquette (196S), three sympatric species in Panama by Fouquette ( 1960b ) , and 10 sym- patric species in Costa Rica by Duellman (1967c). The conclusions drawn by these authors are supported by data from my analy- sis of the mating calls of 76 species of Middle American hylids. The single most important conclusion is that sympatric and synchronic breeding species have distinctly different mat- ing calls. In all cases of which I am aware, these differences in calls are distinguishable by the practiced human ear and are clearly recognizable on audiospectrograms. The frogs of the genus Ptijchohyla are placed into two species groups on morpho- logical characters and on differences in the mating calls. Members of the euthysanota group have a call consisting of a long, well- pulsed note, whereas the call of members of the schmidtorum group consists of a series of short notes. Throughout most of the range of the genus sympatric species pairs breed side by side along streams; in each case the pairs are made up of one species from each group. Duellman and Trueb (1966) noted that the calls of the allopatric species Smilisca puma and sila are not greatly different, whereas Smilisca sordida has a distinctively different call and occurs sympatrically with puma and sila. Duellman and Fouquette (1968) noted that of the four species in the Hyla microcepliala group, the most diver- gence in mating calls occurs in the only two sympatric species in the group — Hyla micro- cepliala and pldebodes. In the Mexican Hyla eximia group, the calls of the geographically adjacent Hyla eximia (long series of notes) and Hyla eu- phorbiacea (short series of short notes) are distinctly different. The calls of the widely allopatric Hyla etiphorbiacea and walked are very much alike. Hyla plicata occurs sym- patrically with eximia and differs from exi- mia by having a long, trilled note. In the Middle American members of the Hyla boans group, the ranges of boans and crepitans are mutually exclusive, whereas rosenbergi oc- curs sympatrically with both boans and crepi- tans. Although the number of notes in each call-group, the duration of the notes, and the level of the fundamental frequency are different between boans and crepitans other parameters of the calls are similar. On the other hand, the call of rosenbergi, although structurally the same as in the other members of the group, is notably different by having a much lower dominant frequency (272 cycles per second, as compared with 869 in boans and 1107 in crepitans). Isolating mechanisms sometimes fail; this is strongly suggested by an individual frog obtained at Bejuco, Panama Province, Pan- ama, by Richard G. Zweifel in 1962. Morpho- logically, the frog is intermediate between Hyla crepitans and rosenbergi. A recording obtained of the call of another individual at the same time shows that the call is inter- mediate in some parameters and different from both supposed parental species in other characteristics. Mecham (1960) documented natural hybridization between Hyla cinerea and gratiosa in Alabama. Fouquette (1960b) studied the calls and mating behavior of Hyla ebraccata, micro- 62 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 cephala, and phlebodes in the Canal Zone and concluded that the mating call seems to be the primary isolating mechanism operat- ing to prevent interbreeding of the three spe- cies studied. He provided evidence that the three species have calls that are qualitatively and quantitatively different, and he assumed that females discriminate and respond only to the call of their own species. Fouquette's assumption that the females can discriminate between the calls of their own and other spe- cies seemingly is well founded. Experimental tests by Martof and Thompson ( 195S), Little- john and Michaud (1959), and Snyder and Jameson (1965) showed that in various spe- cies of Ihjla and Psettdacris, the gravid fe- males respond positively to the calls of their own species and generally are indifferent to the calls of other species. Duellman (1967c) studied courtship behavior of 10 species of hylids at a pond in Costa Rica and concluded : "whereas mechanical isolation between some species is obvious, principally due to great differences in size, the more important isolat- ing mechanisms are differences in behavior. Although each species has characteristic call- ing and oviposition sites, these sites are not necessarily exclusive. Consequently, these aspects of courtship and mating cannot be considered as primary mechanisms operating to prevent mismatings." These conclusions are not contradicted by extensive observations on other associations of both pond- and stream-breeding frogs. All existing evidence points to the mating call as an important ethological isolating mechanism that is the result of selective pressures to insure the attraction of females of the species and as an aid in preventing mismatings and the consequent wastage of gametes. Systematic Importance of Mating Calls Most of the studies on mating calls of anurans have been concerned with call differ- entiation and interspecific isolating effects. The use of the mating call in systematic stud- ies has been more limited. Rlair (1963a), Bo- gert (1962), and Porter (1964 and 1966) re- ported on calls of Bufo. Littlejohn (1959) utilized mating calls in his studies on the Australian leptodactylids of the genus Crinia. The mating call has been utilized as a syste- matic tool in Agahjchnis (Duellman, 1963d), Ptychohyla (Duellman, 1963c), Smilisca (Duellman and Trueb, 1966), and in the Hyla microcephala group (Duellman and Fouquette, 1968). Knowledge of differences in mating calls has been useful in recognizing that certain allopatric populations are differ- ent species, such as in Hyla arenicolor and cadaverina (Gorman, 1960), and the lack of differences in mating calls in certain poly- morphic species, such as Hyla ebraccata and weyerae, have aided in the determination of the existence of only one species (Duellman, 1966b). Despite the great amount of work that has been done on anuran mating calls the only existing treatment of mating call along with morphological characters in a large nat- ural group of species is Schi0tz's ( 1967 ) mono- graph of the West African frogs of the family Rhaeophoridae. Schi0tz summarized his work on the mating calls as follows: "Seen as a unit, the voices of the West African Amphibia can be expected to be sub- jected to the following, partly alternative rules : "I. That the voices are in accordance with the morphological characters supporting the taxonomy, so that the species within a genus have characters in common, not shared with species from other genera, and members of genera in one family have characters in com- mon, not shared with genera in other families. II. That the voices, being adaptive char- acters, are influenced by the habitat occupied by the species, or by the complex of exterior factors, physical and biological, characteristic for a habitat. This will imply that members of the same breeding fauna have voices with common characters. III. That it is essential that the voice of a certain species can be distinguished from all other voices it is heard together with, i.e. voices of other members of the same breeding fauna, excepting geographically non-overlap- ping species. This rule would mean that there is the greatest possible diversity in the voices from one breeding fauna. IV. Finally, the possibility exists that the voices have developed according to other rules than those mentioned in I-III. In this ease, no correlation should be found between 1970 DUELLMAN: HYLID FROGS 63 the voices and the taxonomy or the habitat preference.'' Schi0tz is to be envied of the vocalizations of West African rhacophorids; the nature of the generic and familial characters of mating calls that he discusses at length ( 1967, pp. 294-295) is substantially different, at least at the generic level, in Middle American hylids. Although members of some genera, such as Pseudacris, Phrynohyas, and some species groups in Hyla and Ptychohyla have several call parameters in common with other mem- bers of the same taxonomic group, an equal number of groups are not so readily charac- terized. For example, the trill-like call of Hyla pictipes is not greatly different from the trills of members of the Ptychohyla euthy- sanota group, and the series of nasal notes produced by Hyla eximia is more like the call of Hyla staufferi and certain other members of the predominantly South American Hyla ru- bra group than it is like the calls of other members of the North American Hyla eximia group. Schi0tz's second rule does not seem to apply to Middle American hylids, except in the most general way. I have serious doubts about the influence of the habitat on the vocalizations, except for the tendency to have a weak voice or no voice in certain stream- breeding frogs. The various kinds of voices known in Middle American hylids show no definitive correlation with habitat. Frogs hav- ing a long, well-pulsed note call from streams and ponds. Calls of single or multiple notes are emitted by frogs that call from trees or low herbaceous vegetation, along streams or around ponds. I have discussed previously the divergence in calls in sympatric species, a point made by Schi0tz in his third rule. Thus, it is obvious that to the taxonomist the voice is a valid recognition character. The trained ear can discern anuran species as readily as the or- nithologist can identify birds on the basis of their songs. In each of the species accounts, the mating call, when known, is described in general terms, and the parameters of the vocal factors are given; these are summarized in table 5. In simple terms, the calls of Middle American hylids can be placed in three groups: calls consisting of one note ( 28 species ) , call groups comprised of a series of like notes (40 spe- cies), and call-groups made up of a primary note followed by a series of secondary notes ( 8 species ) . Usually groups of closely related species fall into only one group, but excep- tions do occur. For example, of the six spe- cies in Smilisca, three are in the first category, one in the second, and two in the third, and in the Hyla rubra group two species are in the first category and three are in the second. On the other hand, all species of Agalychnis are in the first category, all members of the Hyla rivularis, boans, uranochroa, and mio- tympanum groups are in the second category, and all members of the Hyla microcephala group are in the third category. Within groups of closely related species, the kinds of differences between species are variable. Although minor differences in the level of the fundamental and dominant fre- quencies are consistent in the Hyla micro- cephala group, the most striking difference is in the phase of the notes — monophasic versus diphasic structure of primary and secondary notes. In the Hyla rivularis group, the pri- mary interspecific differences are in note repe- tition rate and the level of the dominant fre- quency, whereas in Smilisca, the duration and pulse rate are significant factors. Thus, it seems that no general rule can be applied regarding significance of vocal factors; each group of species has its own combination of characters and kinds of interspecific differ- ences. Although similarities in mating calls be- tween two or more species might be an indi- cation of relationships among those species, such conclusions can be justified only when other criteria (morphology, development, be- havior) lend support. Frogs have rather lim- ited vocal abilities; consequently, the occur- rence of similar kinds of calls in widely allo- patric species is to be expected. The disre- gard of morphological characters by Blair ( 1959 and 1960 ) resulted in his placing of Smilisca haudinii in the Hyla versicolor group and Hyla staufferi in the Hyla eximia group, both solely on the basis of call structure. Throughout the course of the present study, I have relied on the mating calls as an aid in the identification of sympatric species and 64 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TABLE 5 Characteristics of the Mating Calls of Middle American Hylid Frogs. Values Given Are Means & Species > One Note: Agahjchnis annae 13 Agalychnis callidryas" 25 Agalychnis litodryas 1 Agalychnis morlettii ... 8 Agahjchnis saltatof 2 Agalychnis sparrelli 2 Gastrotheca ceratophrys 1 Hyla houlengeri 8 Hyla chaneque 5 Hyla erythromma 1 Hyla lancasteri 9 Hyla legleri 8 Hyla pictipes 7 Hyla plicata 3 Hyla rostrata 7 Hyla subocnlaris 2 Paclujmedusa dacnicolor 6 Phrynohyas venulosa 7 Phyllomedusa lemur 2 Plectrohyla ixil 2 Ptycholujla euthysanota 7 Ptychohyla leonhardschultzei 2 Ptycholujla spinipollex 1 Smilisca cyanosticta" 10 Smilisca phaeotaa 10 Smilisca sordida" 19 Triprion petasatus 7 Triprion spatulatus 6 Series of Short Notes: Acris crepitans 1 Anotheca spinosa 1 Hyla angustilineata 1 Hyla arhorescandens 1 Hyla arenicolor _. 13 Hyla hoans 3 Hyla hromeliacia 1 3 o O O o Z OS c o ' — • *J3 o a c o es 3 CD o c V 3 C o Q 1 0.5 0.31 42 1 2.0 0.16 189 1 3.0 0.15 105 1 0.3 0.13 58 1 0.5 0.10 108 1 4.0 0.37 75 1 0.1 O.OS 1 0.5 0.35 101 1 1.0 0.59 59 1 1.5 0.62 26 1 13.0 0.07 150 1 14.0 0.29 108 1 1.0 0.32 123 1 40.0 0.63 90 1 0.5 0.69 51 1 4.0 0.53 43 1 1.0 0.23 159 1 47.0 0.30 161 1 2.0 0.25 108 1 7.0 0.22 200 1 15.0 0.62 96 1 1.0 0.76 77 1 0.5 0.46 147 1 3.0 0.38 147 1 2.0 0.31 116 1 0.4 0.29 105 1 48.0 0.30 85 1 13.0 ...... 0.85 99 161 182 104 172 120 94 800 71 87 149 96 56 153 159 114 700 145 143 123 287 103 1165 1975 1664 1171 1867 568 800 1611 1674 2266 1525 1274 2591 1495 918 2200 1727 1622 2396 2100 3100 2750 4300 841 372 1216 2096 1745 many 128 2 19 6 5 120 137 1 2 1 69 29 69 1 60 0.05 0.10 0.10 0.25 0.64 0.26 0.14 70 220 90 80 26 107 195 175 540 87 74 102 114 135 3150 540 1653 2072 2329 S69 3100 1970 DUELLMAN: HYLID FROGS TABLE 5 — (Continued) 65 Hyla cadaverina 4 Hyla colymba 3 Hyla crepitans 3 Hyla debilis 8 Hyla elaeochroa 15 Hyla euphorbiacea 23 Hyla eximia 34 Hyla godmani 7 Hyla hazelae 2 Hyla loquax . 9 Hyla melanommab 8 Hyla miotympanum 27 Hyla picta 11 Hyla pseudopuma 2 Hyla regilla 1 Hyla rividaris 7 Hyla rosenbergi 5 Hyla rubra 5 Hyla rufiocuUs ___ 2 Hyla rufitela ..... 3 Hyla salvadorensis 4 Hyla smithii 3 Hyla staufferi 25 Hyla sumichrasti 3 Hyla thorectes 3 Hyla tica ._ 5 Hyla uranochroa 4 Hyla icalkeri __ 4 Pseudacris clarkii 4 Pternohyla fodiens 9 Ttychohyla ignicolor 4 Ptychohyla schmidtorum 4 Smilisca baudinii 20 47 0.14 131 132 2073 58 179 0.05 1S00 3600 4 88 0.04 110 182 1107 6 2.0 12 0.01 5235 19 0.17 42 57 1499 7 25.0 664 0.06 103 108 2168 76 0.23 82 104 2058 18 0.17 60 2920 26 0.06 130 1825 31 0.10 129 2323 4 3.0 72 0.07 277 170 2383 7 5.0 65 0.10 2415 64 0.04 53 2661 2661 3 4.0 45 0.03 85 69 956 30 0.10 121 2420 34 3.0 102 0.02 2420 3 129 0.06 50 136 272 3 0.13 63 61 1581 3 10.0 0.06 87 2320 14 38 0.05 400 1600 4 0.08 2.345 68 0.03 36 1033 2066 19 0.16 120 108 1817 24 154 0.20 71 94 1877 15 24 0.21 67 126 2062 4 37.0 148 0.02 2228 148 0.04 260 992 1969 5 39.0 1090 0.03 120 158 1910 144 0.17 93 78 2554 95 0.25 122 126 2230 8 420 0.08 126 3500 6 360 0.65 105 3400 8 4.0 222 0.11 174 166 351 1+2—6 12.0 240 0.55 85 87 957 1+2—5 311 0.16 97 2504 1+0—18 268 0.12 163 213 5710 1+0—28 284 0.11 152 148 3578 1+0—28 418 0.09 149 162 5388 1+0—23 434 O.OS 149 126 3217 1+1—10 3.0 720 0.13 208 145 743 1+1—6 6.0 600 0.16 108 103 899 Primary and Secondary Notes:0 Gastrotheca nicefori 1 Hyla ebraccata _. 43 Hyla microcephala 91 Hyla phlebodes 34 Hyla robertmertensi 25 Hyla sartori 10 Smilisca puma 28 Smilisca sila 15 " Call sometimes is comprised of two notes. 4 Long notes also produced; not included here. r Number of secondary notes given after plus sign; note repetition rate is for secondary notes; other parame- ters are for primary notes. 66 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 as evidence to support ideas of relationships based on morphological characters. Evolutionary trends in mating calls are not clearly evident. So much of the differen- tion of calls seems to be related to selective pressure by the vocalizations of sympatric species I am unsure that it is possible to de- termine evolutionary trends in any more than a very general way. The primitive type of call probably consisted of a single note, which was drawn out into a trill in some species and fragmented into a series of notes or merely just repeated at a rapid rate in other species, thereby giving rise to calls comprised of a series of like notes. Further modification could have resulted in the development of a longer primary note and a series of shorter secondary notes. In conclusion, it is evident that the mating calls are just as useful in recognition by tax- onomists as by the frogs themselves. How- ever, the various parameters of the mating calls represent only one of several sets of characters possessed by species and should not be used to the exclusion of other char- acters. Taxonomic Criteria in Hylid Frogs Each group of animals is studied in some- what different ways. The kinds of characters used and the importance of these characters in the determination of relationships reflects the judgment of the taxonomists working on the groups. All too often, taxonomic treatises contain no statements by the author about his evaluation of the characters used. Of course, I would be remiss if I did not mention the methodology suggested by the students of numerical taxonomy who give an equal weight to many characters and allow a computer to determine the relationships of the taxa. How- ever, I believe that on the basis of my famili- arity with the animals in life, as well as with the characters exhibited by the preserved specimens, I can justifiably give more weight to some characters than to others and also determine that certain characters are signifi- cant in one group and meaningless in others. The conceptual bases for my taxonomic ar- rangement are discussed below. The Species Concept I completely agree with Simpson ( 1961, p. 150) that the only acceptable definition of species category must have a meaningful re- lation to evolution and further agree with Simpson on the acceptability of Mayr's ( 1942) definition: "Species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups." The acceptance of this defini- tion implies genetic differences in populations, but does not tell us how these differences are expressed. We assume that each species ex- ists as an entity in nature and base our hierarchy of classification on the reality of the species (Burma, 1954). However, we examine phenotypes and draw conclusions that can be proved only by determination of the genotypes. Thus, judgments regarding the nature of the species in hylid frogs have been made with the concepts of genetic and evolutionary species in mind, but the prac- tical bases for determinations have been phenotypic expressions (morphological and behavioral) of supposed genetic traits. The definition of species with which I am thoroughly familiar in life and for which I have available a variety of material (pre- served adults, skeletons, tadpoles, and re- cordings of mating calls) is relatively easy, except in certain cases of vicariant popula- tions. The demonstration of geographical, and especially ecological, sympatry is a cri- terion which I have used to determine the specific status of certain taxa. In most cases, this evidence has been further supplemented by differences in mating calls or larval mor- phology, when the adults were exceedingly similar. Thus, the specific nature of several species pairs (Hyla boulengeri and wstrata, Hyla microcephala underwoodi and H. phle- bodes, Smilisca sila and sordida, as examples) have been ascertained. The criteria for species are not consistent throughout the taxonomic treatment for two reasons. First, characters that are useful in certain groups are either absent, invariable, or so variable as to be meaningless in others. For example, the tadpoles of the species of Plectwhyla and Ptycholujla possess charac- ters or combinations of characters by which the tadpoles of the different species can be 1970 DUELLMAN: HYLID FROGS 67 identified readily. Contrariwise, the tadpoles of the species Agalychnis are so nearly alike that identification is exceedingly difficult or impossible. The mating calls of some species are very diagnostic; in others, the calls are little different from other allopatric species. In some groups of species, size and propor- tions are useful in identification, whereas in others, such as the members of the Hyla microcephala group, each proportion seems to vary independently in each sample. Ob- viously, the characteristics of the mating call cannot be relied upon in those groups in which the species are mute (Hyla bistincta and mixomaculata groups and some species of Plectroliyla) . The second reason for incon- sistency is the absence of certain kinds of data. The lack of tadpoles and recordings of the five species in the Hyla miliaria group necessitated the definition of those species solely on the basis of the morphological char- acters of the adults. If all of the information were available for all of the species, more satisfactory and universal sets of criteria could be used. Despite the approach to the problem of defining species on the conceptual basis of the genetic species, it has been necessary to resort to the practical morphological methods in most instances. The utilization of the de- gree of differences has been necessary in deal- ing with many allopatric populations. Thus, some populations are recognized as species distinct from other populations solely because the differences in certain morphological char- acters were much greater between the sam- ples than within samples. In conclusion, I emphasize that my ten- dency is to lump, rather than to split. Some of my colleagues probably have come to feel that I have demonstrated otherwise in my naming of several new species in the past few years, but if I had been basing my ideas on few preserved specimens instead of bio- logical populations, the number would have been many more. This is evidenced by my early study on Phrynohyas ( 1956a) based only on preserved material, in which I accounted for five species in Middle America, whereas now I recognize only one. Intraspecific Variation and Subspecies The treatment of intraspecific variation, especially geographically, often invokes emo- tional reactions from many taxonomists. The splitters would recognize each variant popu- lation taxonomically, whereas the lumpers would abandon the use of the concept. I have tried to take a reasonable approach to the subspecies and in general have been extremely conservative. Detailed statistical analyses of many characters will, and have in some cases, demonstrate statistical differences in populations, which could be, and have been in some cases, named. The taxonomic recognition of populations exhibiting minor differences often obscures many biological facts and usually contributes nothing to our understanding of the nature of variation and the correlation of variation with environmental changes, if any. The most remarkable example of variation in a Middle American hylid is that displayed by Hyla lancasteri, which is so distinctly differ- ent on the upper slopes of Cerro Pando from elsewhere in the range that the population there might even have been accorded generic status. Trueb (1968a) clearly demonstrated that the fantastic "spiny frog" on Cerro Pando is an altitudinal variant of the rather non- descript Hyla lancasteri on the lowlands. The altitudinal gradient in structure, color, and behavior of the frog correlates with environ- mental gradients. This extreme case has caused me to wonder if some other distinctive allopatric species might actually be the ends of clines. I have recognized few subspecies among Middle American hylids. My criteria for subspecies have been: 1) Allopatric adjacent (or probably adjacent) ranges. 2) Distinct morphological differences that are constant, or nearly so, within each population. 3) Like mating calls. 4) Narrow areas of intergrada- tion usually associated with a physical barrier or ecotone. Criteria such as these are applica- ble to species in which certain populations have undergone differentiation in response to isolation or to differences in environments. Thus, the recognition of two subspecies each in Hyla melanomma, H. pseudopinna, Ptycho- hyla euthysanota, and P. schmidtorum is based in part on the separation of the subspecies by 68 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 a physical barrier, which provides ecological conditions unsuitable for the species. The ranges of the subspecies of Hyla staufferi and Triprion spatulatus are separated by ecologi- cal barriers, in each case a humid forested area between the inhabited drier areas. The subspecies of Hyla microcephala meet and intergrade in an area of transition between wet and dry forest. Care has been exercised not to place cer- tain allopatric populations in one species when only minor differences in structure and color are evident, if information on the mating calls and life histories were not available. On the basis of adult frogs alone, one might con- sider Hyla euphorhiacea to be a subspecies of Hyla eximia, but differences in the mating calls strongly indicate that the two narrowly separated populations are species. The mat- ing calls provide good evidence for the de- termination of distinctness of allopatric popu- lations. The first clue to the relationships of Hyla melanomma and bivocata was provided by recordings of the calls. In some instances, my attempts at con- sistency have lapsed, due mostly to lack of data. While I can demonstrate significant differences in the mating calls of Hyla eximia and euphorhiacea, I have no data on the call of the population of exirnia formerly as- signed to arhoricola, which, because of its allopatric distribution and structural similar- ity, I regard as the same as eximia. Species Groups and Genera The supraspecific groupings of hylid frogs are inherently inconsistent. Within the fam- ily some 30 genera are currently recognized, but about three-fourths of the approximately 500 species are placed in the genus Hyla. Widely divergent species or groups of species have been segregated from the genus Hyla; these include the bizarre casque-headed gen- era, such as Aparasphenodon, Pternohyla, and Triprion, other genera that are distinctive in osteological features (Anotheca and Hemi- phraetus), and some that have peculiar life histories, such as exhibited by Cryptoba- trachus and Gastrotheca. The nature of the vocal sacs has been used in separate Smilisca and Phrynohyas from Hyla, whereas progres- sive ossification of the skull and the develop- ment of a cranial casque provide the generic characters to separate Osteocephalus and Trachycephalus from Phrynohyas. Other gen- era are recognized on more subtle characters. For example, the genus Ptychohyla differs from Hyla solely by the presence of large ventrolateral glands in the males. The genus Plectrohyla has been recognized formerly only on the basis of the absence of a quadratojugal and the presence of an enlarged, protruding prepollical spine. The absence of a quadrato- jugal is characteristic of many species of Hyla, and members of several species groups of Hyla have a protruding prepollical spine. I have taken a conservative view of genera and have recognized generically only those groups (genus Hyla is an exception) that assuredly represent a single phyletic line and that display a unique combination of mor- phological and behavioral traits, plus a prob- able paleogeographic history that has been the basis for the evolutionary separation of the group. For the most part, I have followed the currently accepted generic groupings, principally because the key to many phyletic lines must await the accumulation of data on some of the presently poorly known groups in South America. In this regard a treatment of Middle American hylid frogs cannot take into consideration the phylogenetic relation- ships of the casque-headed and non-casque- headed frogs currently assigned to the genus Gastrotheca, represented by nicefori and ce- ratophrys, respectively, in Central America and by many species in South America. Like- wise, the two Central American species of Phyllomedusa (lemur and venusta) repre- sent extremes of variation within the genus, which has a wide array of species in South America. In contrast to some of the weakly defined genera some species groups in the genus Hyla are widely divergent. For example, the large fringe-limbed Hyla with heavily ossified skulls are in marked contrast to the small spe- cies in the Hyla microcephala group, which have weakly ossified skulls. Generic recogni- tion of some of these diverse groups is possi- ble on morphological basis, but again the lack of knowledge about South American relatives precludes an understanding of the 1970 DUELLMAN: HYLID FROGS entire range of variation within the groups and their relationships with other groups. The definition of species groups is based on the premise that all of the members of a given group have a common ancestor. Spe- cies groups, like genera, are not necessarily defined on corresponding sets of characters. For example, in some of the lowland groups of Hyla that are principally South American in distribution, the larval characters are not heavily relied upon to show affinities of the species, whereas some of the principal char- acters in the definition of groups of stream- breeding hylids in Mexico are those of the tadpoles. It may seem to some taxonomists that I have overly split the species groups, even to the recognition of "groups" that con- tain only one species. This has been done in cases where the inclusion of a certain species in another group would result in the break- down of the group characters. Moreover, and more importantly, each species group is considered to represent one phyletic line. Naturally, the supposed points of divergence of various phyletic lines is variable; conse- quently, the inclusion of several phyletic lines in one large group is possible, but not practi- cal for our purpose. Thus, where I recognize the pictipes, rivularis, salvadorensis, and ura- nochroa groups in the genus Hyla in Central America and consider all of these to be re- lated to one another, the divergent adapta- tions in the various groups are such that definition of a composite group is nearly im- possible. IDENTIFICATION OF MIDDLE AMERICAN HYLID FROGS The construction of keys to the identifica- tion of the Middle American hylids has been a difficult task, one in which I feel that I have been only moderately successful. Ideally, a good key will permit the identification of specimens of either sex to species or sub- species; such is not the case with the follow- ing keys, because a person unfamiliar with the general appearance of frogs of the genera Ptyclwhyla and Smilisca will not be able to allocate females to their proper genus. Ju- veniles of most species are difficult or impossi- ble to identify by means of the keys, which have been constructed for adult males. One key is provided to the genera and one each for those genera in Middle America represented by two or more species; thus, there are no generic keys for Acris, Anotheca, Hemiphr actus, Pachymedusa, Phrynohyas, and Pseudacris. The generic keys are in al- phabetical order by the generic name. A single key to the 73 species of Middle Ameri- can Hyla proved to be unworkable. Conse- quently, three keys to the species in three geographic regions are presented. The keys are designed to be used in con- junction with text figures 3-11, to which references are given in the keys. The colored plates are especially helpful in identifying many species and should be used with the diagnoses and descriptions. As a final com- mentary on the use of any one of the keys, I quote Stuart (1955, p. 10): ". . . the worker who knows what species he has before him should experience few difficulties in its use." Key to the Genera of Meddle American Hylid Frogs 1. Pupil vertically elliptical (fig. 5A); dor- sum usually bright green in life ( blue in preservative) ~ 2 Pupil horizontally elliptical (fig. 5B); dorsum variable 4 2. No webbing on hands and feet; palpe- bral membrane clear .. Phyllomedusa Some webbing on hands and feet; pal- pebral membrane usually reticulated (fig. 5B) 3 3. Head shallow, depth less than 40 per cent of length; discs large; fingers at least one-half webbed; iris red or orange and palpebral membrane re- ticulated (iris yellow and palpebral membrane clear in calcarifer) Agalych n is Head deep, depth more than 50 per cent of length; fingers webbed bas- ally; iris gold with black reticula- tions; palpebral membrane reticu- lated . Pachymedusa 4. Skin co-ossified with skull; extensive bony labial flanges present; fingers no more than one-half webbed 5 Skin not co-ossified with skull, or, if 70 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 so, bony labial flanges absent; web- bing variable 6 5. A prenasal bone (fig. 17D) present; labial shelf greatly expanded later- ally; body moderately slender; head much longer than wide _~. Triprion Prenasal bone absent; labial shelf mod- erately expanded laterally; body short, squat, toad-like; head only slightly longer than wide .... Pternohyla 6. Fingers long, essentially unwebbed, lacking nuptial excrescences in males; head as broad as long 7 Fingers not long and lacking webs, or, if so, males having nuptial excres- censes or size small (less than 30 mm. in snout- vent length); head variable 9 7. A fleshy proboscis (fig. 41); head tri- angular in dorsal view . Hemiphractus No fleshy proboscis; head not triangu- lar in dorsal view 8 8. Skin co-ossified with skull; long dor- sally directed spines on periphery of roofing bones of skull; no brood pouch in females ..... Anotheca Skin co-ossified or not; no spines on skull; a brood pouch in females Gastrotheca 9. Skin on dorsum thick, glandular, and tuberculate; hands and feet large with large discs and extensive web- bing; males having paired lateral vo- cal sacs behind angles of jaws (fig. 7D) and lacking projecting prepol- lical spines (fig. 11D) .... Phrynohyas Skin on dorsum not thick and glandu- lar, or, if so, hands and feet not hav- ing large discs and extensive web- bing and males having single subgular vocal sacs and projecting prepollical spines; vocal sacs not be- hind angles of jaws .. 10 10. Head large, deep; arms robust; skin thick and glandular; males having projecting prepollical spines (fig. 11D) Plectrohyla Males lacking projecting prepollical spines, or, if present, head shallow, arms slender, and skin not thick and glandular, or hands and feet fully webbed and dermal fringes present on arms and feet 11 11. Small frogs having pointed snouts, small or unexpanded discs, and only rudimentary webbing on hands 12 Frogs of variable size; if snouts pointed, discs expanded and hands at least one-third webbed .. 13 12. Dorsum rugose, discs not expanded; feet extensively webbed Acris Dorsum smooth, discs barely ex- panded; feet slightly webbed Pseudacris 13. Moderate to large-sized frogs; males having paired subgular vocal sacs (fig. 7C); dorsum marked with blotches; limbs barred Smilisca Size and color variable; males having single, median, subgular vocal sacs (fig. 7A) 14 14. Breeding males having large, usually brown or orange, ventrolateral glands (fig. 9A) .. Ptychohyla Seventy-two other species .. Hijla* Key to the Species of Agalychnis 1. Flanks uniformly colored, lacking verti- cal or diagonal bars 2 Flanks barred 6 2. Hands no more than one-half webbed; size small (males, 47 mm.; females, 62 mm. ) ; flanks blue; dorsum usually marked with wavy transverse lines _ A. salt at or Hands at least two-thirds webbed; size larger; flanks variable; dorsum lacking wavy transverse lines __. .. 3 3. Hands immense, fully webbed, and with large discs; snout long and low 4 Hands smaller, not fully webbed, and with smaller discs; snout sloping and shorter 5 4. Hands, feet, flanks, anterior and pos- terior surfaces of thighs deep yellow 3 Females of Smilisca and Ptychohyla, as well as non-breeding males of the latter, will key out to Hyla. 1970 DUELLMAN: HYLID FROGS 71 to orange; dorsum usually marked with black-bordered white spots A. spurrelli Hands, feet, flanks, anterior and pos- terior surfaces of thighs lacking pig- ment; dorsum uniform green _ A. litodryas 5. Flanks and anterior and posterior sur- faces of thighs blue; iris yellow to orange in life . A. annae Flanks and anterior and posterior sur- faces of thighs orange; iris red in life A. moreletii 6. Flanks orange or yellow with dark bars; thighs and upper arms barred; der- mal appendage present on heel (fig. 4B) .. 7 Flanks blue or brown with creamy white bars; thighs and upper arms not barred; dermal appendage lack- ing on heel ..... A. callidryas 7. Extensive dermal folds on forearm and large dermal flaps on foot; snout truncate .. _ A. craspedopus Only dermal appendage is flap on heel; snout sloping A. calcarifer Key to the Middle American Species of Gastrotheca Skin of head co-ossified with skull; no tri- angular dermal flap on upper eyelid; flanks and posterior surfaces of thighs darker than dorsum G. nicefori Skin of head not co-ossified with skull; a triangular dermal flap on upper eye- lid (fig. 4J); flanks and posterior sur- faces of thighs not darker than dor- sum G. ceratophrys Key to the Species and Subspecies of Hyla in Mexico ( Northwest of the Isthmus of Tehuantepec) 1. Small species (less than 35 mm. in snout-vent length) lacking a tym- panum 2 Size variable; tympanum present (upper edge may be concealed by supra- tympanic fold) 6 2. Dorsal surfaces of thighs unicolor .... 3 Dorsal surfaces of thighs marked by dark transverse bars ..... 4 3. Feet two-thirds webbed; large tuber- cles present below anal opening; shanks and feet strongly barred .. H. pinorum Feet fully webbed; no large tubercles below anal opening; shanks and feet weakly barred H. mtbicola 4. Feet fully webbed H. mixe Feet three-fourths webbed 5 5. Dorsum reddish brown H, mixomaculata Dorsum yellowish tan H. pellita 6. Small species (males having snout- vent lengths of less than 30 mm.) with an axillary membrane (fig. 4E ) ; dorsum usually yellow or tan; thighs uniformly yellow or tan; no difference in color on dorsal and posterior surfaces _ 7 Size and axillary membrane variable; thighs not uniformly yellow or tan .16 7. Dorsolateral light stripes present; flanks usually darker than dorsum, which is unicolor yellow or tan or marked by small dark spots 8 Dorsolateral light stripes absent; flanks variable; dorsum unicolor yellow or tan or with large markings 10 8. Head narrow; side of head and flanks dark brown; dorsolateral stripe nar- row, usually extending to groin H. robertmertensi Head wider; side of head and flanks yellow; dorsolateral stripe wide, not extending to groin 9 9. Distinct dark brown flecks on forearms and shanks; small (males to 21.4 mm. in snout-vent length) H. picta No distinct dark brown flecks on fore- arms and shanks; larger (males to 26 mm. in snout-vent length) H. smithii 10. Dorsum uniform or with small flecks ...11 Dorsum with dark markings 14 72 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 11. Dorsum uniform .12 Dorsum marked by small flecks 13 12. Tarsal fold present ( fig. 4C ) ; tympanic ring distinct H. dendroscarta Tarsal fold absent; tympanic ring weakly defined H. sumichrasti 13. Diameter of tympanum less than 43 per cent of diameter of eye; large flecks on dorsum H. melanomma bivocata Diameter of tympanum more than 50 per cent of diameter of eye; small flecks on dorsum H. melanomma melanomma 14. Flanks dark; dorsal pattern usually consisting of a dark hour-glass- shaped figure H. ebraccata Flanks usually colored like dorsum; pattern not consisting of one large mark on back 15 15. Dark chevron-shaped marks on dor- sum; distinct dark bars on shanks __ H. sartori Dark dashes, sometimes interconnected to form X-shaped mark on back; ill- defined bars on shanks ..... H. microcephala underaoodi 16. Snout acutely rounded; digital discs small; webbing on hand vestigial; dorsum usually green with spots or dashes in a linear arrangement; a dark brown face mask present; males not exceeding 45 mm. in snout-vent length 17 Snout not acutely rounded and digital discs not small, or, if so, dorsum not green and no face mask present 21 17. A dark interorbital triangular mark 18 No dark interorbital triangular mark _. 19 18. Toes about two-thirds webbed; dorsum smooth H. regilla curta Toes about one-half webbed; dorsum pustulate .... H. regilla hypochondriaca 19. Posterior surfaces of thighs brown with yellow spots H. eaphorbiacea Posterior surfaces of thighs lacking yel- low spots 20 20. Fifth toe webbed to base of penulti- mate phalanx; larger (males to 44 mm. in snout-vent length) .... H. plicata Fifth toe webbed to distal end of ante- penultimate phalanx; smaller (males to 36 mm. in snout-vent length) H. eximia 21. Large frogs with a dermal fringe along the lateral edge of the forearm and foot (fig. 4A); feet nearly fully webbed; fingers two-thirds webbed ... 22 Size variable; feet no more than three- fourths webbed, or, if so, fingers webbed only basally; no dermal fringe on edge of forearm and foot... 23 22. Dorsum and flanks mottled reddish brown and dark brown; prepollex in males spatulate, bare H. valancifer Dorsum pale; flanks and anterior and posterior surfaces of thighs dark; prepollex in males bearing a clump of spines (fig. 11C) H. echituita 23. Moderate-sized frogs having round snout, pale dorsum (usually without pattern), extensive axillary mem- brane (fig. 4E) and fingers more than one-half webbed 24 Size variable; axillary membrane ab- sent, or, if present, pattern not as described and hands less than one- half webbed .... 25 24. Webbing and hidden surfaces of thighs red in life; canthus rounded; snout bluntly rounded H. loquax Webbing and hidden surfaces of thighs yellow in life; canthus angular; snout acutely rounded H. godmani 25. Dorsum tuberculate; webbing absent on hand; dorsum dull gray or tan with irregular darker spots 26 Dorsum smooth, or, if tuberculate, webbing present on hand and col- oration not as described 27 26. Feet about three-fourths webbed; di- ameter of tympanum about one-half that of eye; discs small ... H. cadaverina Feet about one-half webbed; diameter of tympanum about two-thirds that of eye; discs larger H. arenicolor 1970 DUELLMAN: HYLID FROGS 73 27. Vocal slits present in males _.. — 28 Vocal slits absent in males ~ — 37 28. Small frogs ( snout-vent length in males less than 30 mm.); snout pointed; dorsum gray, tan, pale green, or yel- low with or without dull green or brown markings 29 Larger frogs; snout not pointed, or, if so, color pattern not as described . 30 29. Head narrow; snout protruding; web- bing vestigial between first and sec- ond toes (fig. 4D); nuptial excres- cence absent H. staufferi stanfferi Head broad, flat; snout not protruding; webbing present between first and second toes; nuptial excrescence present H. smaragdina 30. Dorsum uniform green or with tan mot- tling posteriorly; venter uniform white or yellow 31 Dorsum uniform brown or marked with dark blotches or spots; venter vari- able . 34 31. Snout acutely rounded in dorsal pro- file; limbs slender; anal opening at upper level of thighs; belly white ... 32 Snout bluntly rounded in dorsal pro- file; limbs more robust; anal opening at midlevel of thighs; belly yellow or dull cream .33 32. Axillary membrane present (fig. 4E); feet two-thirds webbed; white stripe on outer edges of limbs distinct; iris red in life H. erythromma Axillary membrane absent; feet three- fourths webbed; white stripe on outer edges of limbs indistinct; iris golden in life H. miotympanum 33. Venter yellow; canthal stripe bronze; webbing on hands vestigial; feet one- half webbed; snout rounded in lateral profile H. hazelae Venter white to dull cream; canthal stripe black; hands one-fourth webbed; feet two-thirds webbed; snout truncate in lateral profile H. arborescandens 34. Snout short, truncate; venter white with black spots on chest .... H. thorectes Snout variable; venter not white with black spots on chest .35 35. Transverse bands on dorsal surfaces of limbs - 36 Transverse bands absent on dorsal sur- faces of limbs; posterior surfaces of thighs marked with creamy yellow flecks H. bistincta 36. Dorsum tuberculate; diameter of tym- panum less than 50 per cent that of eye; anal opening at midlevel of thighs; snout truncate in both sexes H. chaneque Dorsum smooth; diameter of tym- panum more than 50 per cent that of eye; anal opening at ventral sur- faces of thighs; snout acuminate and protruding in males, blunt in fe- males H. taeniopus 37. Snout acuminate; fingers one-half webbed; distinct transverse bands on limbs; venter yellow; prepollex mod- erately enlarged and devoid of a nuptial excrescence H. altipotens Snout bluntly rounded or truncate; fin- gers less than one-half webbed; col- oration not as described; prepollex greatly enlarged with or without nuptial excrescence 38 38. Axillary membrane present (fig. 4E); nuptial excrescences absent; skin thin .39 Axillary membrane absent; nuptial ex- crescences present; skin thick and glandular 40 39. Snout in dorsal profile truncate; diam- eter of tympanum less than 50 per cent of eye; feet three-fourths webbed; dorsum dark green with darker reticulations .... H. charadricola Snout in dorsal profile pointed; diame- ter of tympanum more than 50 per cent of eye; feet two-thirds webbed; dorsum yellowish tan with brown flecks H. chryses 40. Tympanum concealed by supratym- panic fold; nuptial excrescence con- sisting of clump of spines (fig. 11C); snout round H. pachyderma 74 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Tympanum not concealed; nuptial ex- crescence consisting of small spin- ules; snout variable 41 41. Snout truncate in dorsal view; rostral keel absent; thoracic fold absent; dorsum pale; flanks and edges of limbs dark brown .. H. pentheter Snout rounded in dorsal view, or, if truncate, a rostral keel present (fig. 4G); webbing on hand vestigial; thoracic fold present or absent; dor- sum not paler than flanks .. 42 42. Snout truncate in dorsal and lateral profiles; rostral keel present (fig. 4G) H. siopela Snout rounded in dorsal and lateral profiles; rostral keel absent .. 43 43. Venter uniformly white H. bogertae Venter dusky or spotted .._ —44 44. Thoracic fold present (fig. 4F); feet four-fifths webbed _ .. H. robertsorum Thoracic fold absent; feet fully webbed H. crassa Key to the Species and Subspecies of Hijla in Northern Central America ( Isthmus of Tehuantepec-Honduras Including Yucatan Peninsula ) 1. Small species (less than 35 mm. in snout- vent length) having unpig- mented or uniformly yellow thighs; dorsum usually yellow with darker markings 2 Mostly larger species; thighs not uni- formly colored or lacking pigment; dorsum not yellow 8 2. Dorsolateral white lines present, con- tinuous to groin or nearly so 3 Dorsolateral white lines absent, or, if present, not extending posterior to sacrum 4 3. Dorsolateral line broad; flanks yellow H. picta Dorsolateral line narrow; flanks and sides of head dark brown _ H. robertmertensi 4. Snout truncate in dorsal view .. 5 Snout acuminate or acutely rounded in dorsal view 6 5. Dorsal pattern consisting of irregular dark dashes, usually forming in X- shaped mark in scapular region and an interorbital bar .. H. microcepliala underwoodi Dorsal pattern consisting of dark hour- glass-shaped mark, small spots, or nothing H. ebraccata 6. Snout acutely rounded; dorsum uni- formly yellowish tan; plantar sur- faces of feet and edge of chin suf- fused with dark pigment H. bromeUacia Snout acuminate; dorsum yellow, pale green, or pale gray with small dark flecks or no markings; venter white..-. 7 7. Tarsal fold absent; tympanum indis- tinct; axillary membrane abbrevi- ated; dorsum without dark flecks .. H. sumichrasti Tarsal fold present (fig. 4C); tym- panum distinct; axillary membrane extending at least midway to elbow; dark flecks present on dorsum H. melanomma bivocata 8. Moderately large species (more than 45 mm. in snout-vent length); nar- row middorsal dark line usually pres- ent on tan or gray dorsum; projecting prepollex in males (fig. 11D) H. crepitans No middorsal dark line or projecting prepollex .— 9 9. Dorsum green with or without brown canthal stripe and brown spots or stripes posteriorly; small species ( less than 40 mm. snout-vent length) . .10 Dorsum not green, or, if so, large spe- cies with heavy brown mottling dor- sally and dark flanks -12 10. Dark brown canthal stripe and brown spots or stripes usually present pos- teriorly on dorsum — 11 Dorsum uniform green or marked with faint tan blotches or darker green reticulations .. H. miotympanum 11, Posterior surfaces of thighs dark brown with yellow spots H. euphorbiacea Posterior surfaces of thighs uniform tan — H. walkeri 1970 DUELLMAN: HYLID FROGS 75 12. Small spt-cies (less than 30 mm. snout- vent length) with acuminate pro- truding snout, dark longitudinal markings on gray or tan dorsum, and webbing reduced between first and second toes (fig. 4D) H. stanfferi staufferi Larger species lacking an acuminate protruding snout and having well- developed web between first and second toes; dorsal pattern variable, not linear .. 13 13. Dorsum tubercular; flanks dark brown or black with pale flecks; dorsum mottled black or dark brown and dark green; size large, to 80 mm. H. chaneque Dorsum smooth; flanks pale; dorsum tan, pale brown, or gray, not boldly mottled; size medium, less than 50 mm. .14 14. Extensive axillary membrane (fig. 4E); webbing red in life H. loquax No axillary membrane; webbing brown H. salvadorensis Key to the Species and Subspecies of Hyla in Lower Central America ( Nicaracua-Panama ) 1. Larger species (adult males more than 40 mm. in snout-vent length); feet at least three-fourths webbed; a pro- jecting prepollex present ..... ..... 2 Smaller species (adult males less than 50 mm. in snout-vent length); web- bing of feet variable; prepollex en- larged or not, but never projecting ... 8 2. A scalloped dermal fringe along outer edge of forearm and fourth finger and along outer edge of foot and fifth toe (fig. 4A) 3 No scalloped dermal fold on outer edges of limbs 5 3. Dorsum tubercular; general dorsal col- oration brown; hands and feet im- mense; osteoderms present in adults — H. miliaria Dorsum smooth or nearly so .. 4 4. Dorsum brown; toes about three- fourths webbed; skin co-ossified with skull H. fimbrimembra Dorsum green; toes fully webbed; skin not co-ossified with skull H. thysanota 5. Dorsum green (pale tan with dark flecks in preservative); flanks and posterior surfaces of thighs un- marked; webbing red in life H. rufiteh Dorsum tan or brown, usually with a middorsal dark line; flanks and pos- terior surfaces of thighs dark or pale and marked with dark reticulations or vertical bars; webbing tan or brown in life 6 6. Fourth finger webbed to distal end of antepenultimate phalanx; snout-vent length less than 60 mm H. crepitans Fourth finger webbed to base of disc; snout-vent length of adult males more than 60 mm 7 7. Webbing and posterior surfaces of thighs dark; calcar present (fig. 4B); palpebral membrane reticulated (fig. 5A); hands huge H. boons Webbing pale; posterior surfaces of thighs marked by narrow vertical bars; calcar absent; palpebral mem- brane clear; hands smaller H. rosenbergi S. Snout protruding beyond lower jaw (fig. 3E); webbing vestigial between first and second toes (fig. 4D) 9 Snout not protruding beyond lower jaw; webbing not reduced between first and second toes 14 9. Larger frogs (males to 50 mm. snout- vent length); thighs strongly barred; supratympanic fold black; dorsum blotched or spotted 10 Smaller frogs (males to 40 mm. snout- vent length); thighs weakly barred or plain; supratympanic fold pale brown; dorsum having linear pat- tern 11 10. Dorsum tuberculate; snout subacumi- nate; vocal sac flecked with brown; 76 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 tarsal fold weak; fingers lacking web; black spots absent in scapular re- gion H. houlengeri Dorsum smooth; snout pointed; vocal sac dark gray; tarsal fold absent; trace of web between fingers; two or more elongate black spots in scapu- lar region H. rostrata 11. Snout-vent length more than 30 mm.; diameter of tympanum at least two- thirds of the diameter of the eye; prevomerine elevations about the size of the choanae ___ 12 Snout-vent length less than 30 mm.; tympanum less than half of the di- ameter of the eye; prevomerine ele- vations smaller than choanae 13 12. Thighs mottled posteriorly; discs on fingers about half of the diameter of the tympanum; canthal line faint — H. rubra Thighs faintly barred or plain pos- teriorly; discs on fingers about size of tympanum; canthal line distinct — H. elaeochroa 13. Dorsum brown with irregular dorso- lateral stripes and interrupted para- vertebral stripes; two transverse bars on shanks; interorbital bar pres- ent _. H. staufferi staufferi Dorsum gray with complete dorsolat- eral and paravertebral stripes; longi- tudinal stripe on shank; interorbital bar absent H. staufferi altae 14. Small (males to 30 mm.) yellow frogs with brown dorsal markings and uni- formly yellow thighs 15 Size variable (mostly larger than 30 mm.); thighs not uniformly yellow 18 15. Head broad; scalloped dark mark on dorsal surface of shank; dorsum plain or marked by brown spots or hour-glass-shaped mark— H. ebraccata Head narrow; narrow transverse dashes or longitudinal dark line on shank; dorsum marked with narrow brown dashes, longitudinal lines, or reticu- lations 16 16. Lateral dark stripe, bordered above by narrow white line, extending from snout at least to sacral region 17 Lateral dark stripe indistinct, present only above tympanum and insertion of arm; dorsal markings consisting of narrow lines and dashes, sometimes interconnected H. phlebodes 17. Lateral dark stripe continuous to groin; dorsal pattern consisting of a pair of narrow dark longitudinal lines; dashes or longitudinal line on shanks; interorbital dark bar absent _ H. microcephala microcephala Lateral dark stripe extending to sacral region; dorsal pattern consisting of interconnecting lines and dashes; transverse bars on shanks; interor- bital dark bar present H. microcephala underwoodi 18. Dorsum uniformly yellow or tan, or with small dark brown or red flecks; venter immaculate; granules above insertion of arm; temporal region enlarged 19 Dorsum not uniformly yellow or tan, or, if so, venter spotted; no granules above insertion of arm; temporal re- gion not enlarged __..20 19. Two denticles at symphysis of lower jaw; dark flecks on lips, side of head and temporal region; size larger (males to 32.8 mm.) H. picadoi One denticle at symphysis of lower jaw; dark flecks present on lips in some; size smaller (males to 23.5 mm.) H. zeteki 20. Webbing and posterior surfaces of thighs red 21 Webbing and posterior surfaces of thighs not red 22 21. Snout long; dorsum tan with brown blotches, flanks spotted; nuptial ex- crescence extensive in breeding males H. pseudopuma infucata Snout short; dorsum uniform tan, gray, or brown; flanks cream, unmarked; nuptial excrescences absent—.//, loquax 1970 DUELLMAN: HYLID FROGS 77 22. Dorsum tan with narrow cream dorso- lateral stripes; flanks dark brown; venter flecked with black H. angustilineata Dorsum not marked with cream dorso- lateral stripes .23 23. Iris red in life (usually red or reddish brown in preservative); a white lat- eral stripe present; no yellow spots on flanks or thighs; dorsum green or dark brown 24 Iris not red in life or preservative; no white lateral stripe; yellow spots present or not on flanks and thighs; dorsum tan or green, blotched, streaked, mottled, or unicolor 26 24. Fingers one-half webbed; vocal sac in breeding males dark gray ... H. legleri Fingers one-fourth webbed; vocal sac in breeding males white or creamy yellow 25 25. White labial stripe usually expanded below eye; dorsum dark green or brown; plantar surfaces of feet pig- mented; diameter of tympanum less than 50 per cent of diameter of eye.... _x H. rufioculis White labial stripe not expanded below eye; dorsum green; plantar surfaces of feet unpigmented; diameter of tympanum more than 50 per cent of diameter of eye H. uranochroa 26. Posterior surfaces of thighs unpig- mented except for a yellow spot bor- dered by black; narrow vertical white rostral line continuous with white line on canthus, edge of eyelid, and supratympanic fold; two vertical white or yellow bars on upper lip; size small (26 mm.) ... H. subocitlaris Color not as described 27 27. Dorsum tan, yellow, or pale gray with dark brown streaks, spots, or blotches 28 Dorsum green or brown, spotted, mot- tled, or plain; if tan, no markings evident 29 28. Snout acuminate; dorsum usually tan or yellow with large brown spots or blotches; posterior surfaces of thighs dark brown; flanks brown with yellow spots; venter immacu- late; size medium (48 mm.) H. pseudopuma pseudopuma Snout truncate; dorsum pale tan, yel- lowish tan, or pale gray with brown or gray streaks; posterior surfaces of thighs pale brown; flanks cream; venter spotted or flecked with black; size small (36 mm.) H. rividaris 29. Dorsum pale green or tan (nearly white with scattered dark pigment in some specimens); white stripe on canthus, edge of eyelid, and supra- tympanic fold; large mental gland usually evident H. colymba Color not as described; not mental gland present 30 30. Posterior surfaces of thighs yellow or white with black spots or vertical bars; flanks black and white; snout very short, truncate; fleshy spines present in some populations H. lancasteri Posterior surfaces of thighs dark, uni- color, or with small pale spots; snout not especially short; flanks not boldly marked with black and white . 31 31. Dorsum uniform green or with small dark flecks; broad tan canthal stripe present 32 Dorsum mottled green, black, and brown ( uniform green in some fe- males); no canthal stripe 33 32. Continuous white labial stripe; flanks and thighs dark brown with yellow spots H. xanthosticta Labial stripe interrupted, expanded be- low eye; posterior surfaces of thighs yellow; flanks white H. debilis 33. Snout angular in lateral profile; diam- eter of tympanum equal to about one-third of diameter of eye H. pictipes Snout rounded in lateral profile; di- ameter of tympanum equal to about one-half of diameter of eye .... H. tica 78 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Key to the Middle American Species of Phijllomedusa Small frog (male, 40 mm.); first toe shorter than, and not opposable to second; parotoid glands absent; venter uni- form creamy yellow P. lemur Large frog (female, 86 mm.); first toe longer than and opposable to sec- ond; parotoid glands forming ele- vated dorsolateral ridge; venter orange and dark brown with white spots on chest P. vemista Key to the Species of Plectrohyla 1. Propollical process bifid 2 Prepollical process flat, spur-like, or truncate, but not bifid 3 2. Flanks and anterior surfaces of thighs pale with bold vertical dark bars P. hartwegi Flanks and anterior surfaces of thighs not marked with contrasting colors P. guatemalensis 3. Prepollical process flat, not protrud- ing; vocal slits absent 4 Prepollical process round or pointed; vocal slits present or absent 5 4. Dorsum tubercular; snout bluntly rounded P. pycnochila Dorsum smooth or with few scattered tubercles; snout acuminate P. glandulosa 5. Prepollical process elongate, round, terminally blunt; vocal slits absent .._ ._ P. lacertosa Prepollical process knife-like, termi- nally pointed; vocal slits present or absent 6 6. Large species (90 mm.); vocal slits absent; dorsum smooth except for tubercles on head _. P. avia Small species (less than 50 mm.); vo- cal slits present; dorsum tubercular or smooth (if smooth, no tubercles on head) ..... 7 7. Vertical rostral keel present (fig. 4G and H) ..... 8 Vertical rostral keel absent 9 8. Snout acuminate; dorsum smooth or weakly tuberculate; small dark flecks on flanks P. sagorum Snout blunt; dorsum tuberculate; large brown spots on flanks P. quecchi 9. Snout acuminate; dorsum smooth or weakly tuberculate; lateral light stripe bordered below by narrow dark line usually present P. ixil Snout truncate; dorsum tuberculate; lateral dark line usually present, but light stripe absent P. matudai Key to the Species of Pternohijla Bony ridge extending from point between nostrils to tip of snout; snout in dor- sal profile acutely rounded; tips of digits expanded into small discs; outer edge of inner metatarsal tu- bercle elevated (fig. 4C); vocal sacs connected medially in breeding males P. fodiens No bony ridge extending anteriorly from a point between nostrils; snout bluntly rounded in dorsal profile; tips of digits not expanded; inner metatar- sal tubercle round in section; vocal sacs widely separated medially in breeding males P. dentata Key to the Species and Subspecies of Ptychohijla 1. A weak tarsal fold; outer fingers one- third webbed; males having nuptial spines (fig. 11C); color in life tan or brown with blotches or reticula- tions, never green; iris bronze or copper 2 No tarsal fold; outer fingers having only vestige of web; males lacking nuptial tuberosities; color in life green or brown, iris red or bronze ._ 5 2. Chest, throat, and flanks usually hav- ing black or brown spots; no distinct white stripe on upper lip or on flanks; a faint white line usually present above anus; a rostral keel present 3 Chest, throat, and flanks usually un- spotted; distinct white line on upper 1970 DUELLMAN: HYLID FROGS 79 lip and on flank present or not; white line above anus faint or well defined; no rostral keel — 4 3. Interorbital distance much greater than width of eyelid; spots on throat and chest black; spots only occasionally present on belly; flanks marbled with black and white; nuptial spines small, as many as 80 on one thumb P. leonhardschultzei Interorbital distance about equal to width of eyelid; spots on chest and throat brown or black; spots usually present on belly; flanks having round brown or black spots; nuptial spines moderate in size, conical, seldom more than 60 on one thumb P. spinipollex 4. A distinct, broad, white lateral stripe usually present; usually a distinct white line above anus; a distinct white stripe on upper lip P. euthysanota euthysanota No white lateral stripe; a faint white stripe above anus; no distinct white stripe on upper lip P. euthysanota macrotympanum 5. A distinct, broad, lateral stripe; a white stripe on upper lip expanded to form a large spot below eye; hidden sur- faces of thighs and webs of feet not orange to red in life; internarial area slightly depressed; diameter of tym- panum greater than one-half diame- ter of eye 6 No lateral white stripe; no stripe on upper lip; in life dorsum green; hid- den surfaces of thighs and webs of feet orange or red; internarial area flat; diameter of tympanum less than one-half diameter of eye __ P. ignicolor 6. Webs of feet and posterior surfaces of thighs cream; dorsum in life reddish brown; iris bright red P. schmidtorum schmidtorum Webs of feet and posterior surfaces of thighs pale brown; dorsum in life green; iris reddish bronze P. schmidtorum chamulae Key to the Species of Smilisca 1. Larger frogs (males, 76 mm.; females, 90 mm.) having broad, flat heads and a dark brown or black postor- bital mark encompassing tympan- um 2 Smaller frogs (males, 45 mm.; females, 84 mm.) having narrower heads and lacking a dark brown or black post- orbital mark encompassing tym- panum — - 4 2. Lips barred; flanks cream with bold brown or black mottling in groin; posterior surfaces of thighs brown with cream flecks S. baudinii Lips not barred; narrow white labial stripe present; flanks not cream with bold brown or black mottling in groin; posterior surfaces of thighs variable 3 3. Flanks and anterior and posterior sur- faces of thighs dark brown with pale blue spots on flanks and blue spots on thighs S. cyanosticta Flanks cream with fine black venation; posterior surfaces of thighs pale brown with or without darker flecks of small cream spots S. phaeota 4. Fingers having only vestige of web; diameter of tympanum two-thirds that of eye; dorsum tan with pair of broad brown stripes S. puma Fingers about one-half webbed; diam- eter of tympanum about one-half that of eye; dorsum variously marked with spots or blotches 5 5. Snout short, truncate; vocal sacs in breeding males dark gray or brown; blue spots on flanks and posterior surfaces of thighs S. sila Snout long, sloping, rounded; vocal sacs in breeding males white; cream or pale blue flecks on flanks and pos- terior surfaces of thighs S. sordida Key to Species and Subspecies of Triprion 1. Tip of snout upturned; dermal sphen- 80 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 ethmoid visible through skin; odon- toids absent from palatines; vocal sac bilobate T. petasatus Tip of snout not upturned; dermal sphenethmoid absent; odontoids present on palatines; vocal sac single and median 2 2. Dorsum uniformly yellowish-tan to olive-green or marked by minute flecks or dashes T. spatulatus spatulatus Dorsum yellowish tan with dark brown reticulations and spots T. spatulatus reticulatus ACCOUNTS OF THE GENERA AND SPECIES Genus Pachymedusa Duellman Pachymedusa Duellman, 1968b, p. 5 [type spe- cies, Phyllomedusa dacnicolor Cope, 1864, by orig- inal designation]. Generotype: Phyllomedusa dacnicolor Cope, 1864, by original designation (Duell- man, 1968b). Cope (1866b) placed dacni- color in the genus Agalychnis Cope, 1865a, and the species has since led a spotted history of transfer between Agalychnis and Phyllo- medusa. Etymology: The generic name is derived from the Greek pachy, meaning thick, and the Greek Medousa ( Latin Medusa ) , used in ref- erence to Phyllomedusa and alluding to the heavy body of Pachymedusa dacnicolor. Definition: Frogs of the genus Pachy- medusa are large and have a green dorsum and white spots on the flanks. The pupil is vertically elliptical, and the iris is golden yellow with black reticulations; the palpebral membrane is reticulated. The fingers and toes are webbed basally and have narrow lateral fringes; the terminal discs are large. The first toe is shorter than the second and not oppos- able to the others. The skin on the dorsum is smooth or shagreened and lacks osteoderms; the paratoid glands are diffuse. There is no integumentary-cranial co-ossification. The vo- cal sac is single, median, and subgular. The tongue is much longer than wide and attached only anteriorly. Breeding males have horny brown nuptial excrescences on the thumbs. The skull is deep; its depth is more than half of its length (fig. 21). The parietal plane is barely inclined anteroventrally. The skull is characterized by a large frontoparietal fon- tanelle, robust quadratojugals, and moder- ately developed squamosals with long pos- terior arms and short anterior arms that ex- tend only about one-fourth of the distance to the maxillaries. The premaxillary has a well-developed, posterodorsally inclined alary process. The maxillary bears a moderately deep pars facialis, which at the level of the palatine extends dorsally and connects with the short maxillary process of the nasal. The nasals are large, narrowly separated medially, and in bony contact with the sphenethmoid. The canthal ridge is parallel to the maxillary. The maxillary process of the nasal articulates with the posterior process of the pars facialis. The sphenethmoid is well ossified. The den- tigerous processes of the prevomers are short and situated at an angle to the midline. The pterygoids are robust and have a cartilagi- nous attachment to the prootics. The otic region is moderately small. Teeth are present on the premaxillaries, maxillaries, and pre- vomers, but absent from the palatines and parasphenoid. The teeth are barely spatulate and strongly bifid. The tadpoles are pelagic types with anterior mouths. The lips are infolded laterally and bordered by small pa- pillae, except that the median part of the upper lip is bare. There are two upper and three lower rows of teeth. The spiracle is ventral on the body and sinistral to the mid- line. The caudal musculature is slender, and the fins are deep. The mating call is a single, short, poorly modulated note. The haploid number of chromosomes is 13. Composition of Genus: One species, P. dacnicolor, is included in the genus. Eight hundred and forty-seven preserved frogs, seven skeletons, five lots of tadpoles, and three preserved clutches of eggs have been exam- ined. Distribution: Pachymedusa occurs on the Pacific slopes and lowlands from southern Sonora to the Isthmus of Tehuantepec, Mex- ico. Discussion: Duellman (1968b) suggested that Pachymedusa is a generalized and prob- ably primitive phyllomedusine and represents a hanging relict in the Mesoamerican herpeto- fauna. In this respect, the genus is like Hylac- tophryne in the Leptodactylidae (Lynch, 1968). Pachymedusa dacnicolor (Cope) Phyllomedusa dacnicolor Cope, 1864, p. 181 [holo- type, formerly in U.S.N. M., now lost, from "near Colima," Mexico; John Xantus collector; type locality restricted to Colima, Colima, Mexico by Smith and Taylor (1950, p. 328)]. Brocchi, 1882, p. 68. Bou- lenger, 1882a, p. 426. Kellogg, 1932, p. 143. Funk- houser, 1957, p. 37. Agalychnis dacnicolor Cope, 1866b, p. 86 [trans- fer of Phyllomedusa dacnicolor Cope to Agalychnis Cope, 1865a]. Giinther, 1901 (1885-1902), p. 291. 81 82 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Q^,-~^*~^H^^>J„«1SaMW^»*^«™*"«(»«,'' Fig. 21. Dorsal (A), ventral (B), and lateral (C) views of the skull of Pachymedusa dacnicolor, K.U. No. 84916. x 3. 1970 DUELLMAN: HYLID FROGS 83 Smith and Taylor, 1948, p. 72. Duellman, 1957, p. 29 [synonymized Agalychnis alcorni Taylor, 1952b, with Agalychnis dacnicolor (Cope, 1864)]. Agalychnis alcorni Taylor, 1952b:31, pi. 1 [holo- type, K.U. No. 29763 from "south bank Rio de Te- palcatepec, 800 feet elevation, 17 miles south of Apatzingan, Michoacan," Mexico; J. R. Alcorn collec- tor. Phyllomcdusa alcorni: Funkhouser, 1957, p. 30 [transfer of Agalychnis alcorni Taylor, 1952b, to Phyl- lomedusa Wagler, 1830]. Pachymcdusa dacnicolor: Duellman, 1968b, p. 5 [designation of Phyllomcdusa dacnicolor Cope as type species of Pachymcdusa]. Diagnosis: This large species differs from other phyllomedusine frogs in having rela- tively long and slender fingers and toes with little webbing, short legs, a high head, a gold and black eye; white spots or bars on other- wise uniformly green flanks, and cream- colored thighs. The hand is about one-fourth webbed, and the foot is about one-third webbed. The only Agalychnis lacking blue, yellow, or orange on the flanks and thighs is litodryas, which has fully webbed hands and feet, a shallow head, a dark red eye, and un- pigmented flanks and thighs. The Middle American species of PhyUomedusa lack web- bing. Description: Males of this large species attain a maximum snout-vent length of 82.6 mm., and females reach 103.6 mm. In a series of 20 males from Villa Union, Sinaloa, Mexico, the snout-vent length is 63.1 to 73.1 (mean, 67.6) mm.; the ratio of tibia length to snout- vent length is 0.341 to 0.415 (mean, 0.372); the ratio of foot length to snout-vent length is 0.289 to 0.362 (mean, 0.332); the ratio of head length to snout-vent length is 0.296 to 0.322 (mean, 0.313); the ratio of head width to snout- vent length is 0.292 to 0.345 (mean, 0.316), and the ratio of the diameter of the tympanum to that of the eye is 0.587 to 0.754 (mean, 0.690). Three females from the same locality have snout-vent lengths of 72.0 to 87.6 (mean, 79.2) mm. The females show no significant differences in proportions from the males. Some geographic variation in sizes and proportions is evident (table 6). Individuals of both sexes are noticeably larger in the southern part of the range. The snout-vent length in 20 specimens from the vicinity of Pochutla, Oaxaca, varies from 71.8 to 82.6 (mean, 77.5) mm. Individuals from the Bal- sas Basin in Morelos have proportionately larger tympani; the average ratio of the diam- eter of the tympanum to that of the eye is 0.735; whereas the highest ratio in coastal samples is 0.690. The head is noticeably narrower than the body, and the top of the head is flat. In dorsal profile the snout is rather acutely rounded. In lateral profile, in males, the snout is gently sloped from the eyes to the nostrils and then inclined gradually to the tip of the snout; in females, the snout is inclined gently from the eyes to a point just anterior to the nostrils and then steeply inclined to the tip of the snout (fig. 22). The snout is moderately short, and the nostrils are barely protuberant and situated at a point about two-thirds of the distance from the eyes to the tip of the snout in females and about mid- way between the eyes and the tip of the TABLE 6 Geographical Variation, with Means in Parentheses, in Males of Pachymedusa dacnicolor. Locality N Sinaloa: Villa Union 20 Jalisco: Melaque-La Resolana ._ 7 Michoacan: Coalcoman 20 Morelos: Cuautlixco - 12 Oaxaca: Pochutla 20 Snout-vent Length (mm.) Tibia Length/ S-V L Head Width/ S-V L Tympanum/ Eye 63.1-73.1 0.341-0.415 0.292-0.345 0.587-0.754 (67.6) 58.1-71.9 (0.372) 0.399-0.433 (0.316) 0.323-0.341 (0.690) 0.591-0.727 (65.1) 62.2-75.6 (0.420) 0.391-0.439 (0.329) 0.318-0.337 (0.638) 0.587-0.742 (68.8) 64.5-74.0 (0.416) 0.351-0.411 (0.324) 0.306-0.363 (0.651) 0.639-0.804 (70.2) 71.8-82.6 (0.379) 0.388-0.446 (0.333) 0.301-0.335 (0.735) 0.575-0.781 (77.5) (0.407) (0.317) (0.665) 84 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 snout in males. The canthus is rounded; the loreal region is barely concave, and the lips are thick and moderately flared. A thin der- mal fold extends posteriorly from the eye above the tympanum, and around the pos- terior edge of the tympanum and downward in a distinct fold to the point of insertion of the arm. The fold obliterates the upper edge of the tympanum in all individuals and the posterior edge of the tympanum in about half Fig. 22. Lateral views of heads of Pachijmedusa dacnicolor showing sexual dimorphism in the shape of the snout. A. Male, K.U. No. 78442. B. Female, K.U. No. 78435. X 2. of the specimens. Otherwise, the tympanum is distinct and separated from the eye by a distance equal to about one-third to one-half of the diameter of the tympanum. The upper arms are slender, and the fore- arms are robust. A few small tubercles are present on the ventral surface of each fore- arm, and a distinct, thin, transverse dermal fold is present on the wrist. The fingers are short, robust, and bear moderately large discs; the diameter of the disc on the third finger is equal to about two-thirds of the diameter of the tympanum. The subarticular tubercles are large, subcorneal, and present on the proxi- mal segments of each digit. A large, flattened, tripartite palmar tubercle is present. An elongate, elevated tubercle is present on the prepollex, which is moderately enlarged and in breeding males bears a horny nuptial ex- crescence. Webbing is absent between the first and second fingers and rudimentary be- tween the others (fig. 23A). The hind limbs are very short and robust; the heels of the adpressed limbs barely meet. The tibiotarsal articulation extends to the axilla. A thin, transverse dermal fold is present on the heel, and a distinct, elevated tarsal fold extends the full length of the tarsus. The inner meta- tarsal tubercle is small and conical. The toes are short and heavy and bear discs that are only slightly smaller than those on the fingers. The subarticular tubercles are moderately large and round; the supernumerary tubercles are large and conical. The toes are no more than one-third webbed (fig. 23R). A narrow dermal fringe is present along the edge of the toe. The anal opening is directed ventrally at the midlevel of the thighs. A long, broad anal sheath is present; laterally the anal sheath ex- tends to the ventral surfaces of the thighs. The skin on the dorsum is smooth or sha- greened; in some individuals minute pustules are present above the insertion of the arm. The throat, belly, and ventral surfaces of the thighs are heavily granular. Weak granules are evident on the ventral surfaces of the fore- arms in some specimens; the ventral surfaces of the shanks, feet, and upper arms are smooth. Distinct, elevated pustules are pres- ent on the flanks in most specimens. The tongue is elongate, about twice as long as 1970 DUELLMAN: HYLID FROGS 85 Fig. 23. Hand (A) and foot (B) of Pachymcdusa dacnicolor, K.U. No. 87138. X 3. wide. In some individuals it is deeply notched posteriorly, whereas in others it is shallowly notched or entire; posteriorly, the tongue is free for about one-third of its length. The dentigerous processes of the prevomers are small oblique elevations situated between the moderately large, nearly quadrangular cho- anae. In the series of males from Villa Union, Sinaloa, individuals have three to six teeth on each process and males have a total of six to 11 (mean, 8.8) prevomerine teeth. Fe- males in the same series have five or six teeth on each process and a total of 10 to 12 ( mean, 11.0) prevomerine teeth. The vocal slits ex- tend along the inner edge of the posterior part of the lower jaw. The vocal sac is single, median, subgular, and not greatly distensible. The general coloration of Pachymedusa dacnicolor is green above and dirty white be- low ( pi. 41, fig. 1 ) . The dorsum usually is a rather bright green. Individuals are capable of changing the intensity of the color so that the color change in one individual can range from a pale leaf-green to a dark dull green. The throat and belly are dirty white or creamy white, and the ventral surfaces of the hind limbs vary from pinkish orange to orange- tan. Pale creamy white flecks, spots, or verti- cal bars are present on the flanks, and in some specimens creamy white or yellow flecks, narrowly outlined with black in some speci- mens, are present on the dorsum. The iris is a dark golden bronze heavily flecked with black. Individuals from the northern part of the range, Colima northward, have few, if any, creamy white or yellow spots on the dorsum, whereas individuals from Michoacan and Morelos usually have a few distinct dorsal spots. Specimens from Guerrero and espe- cially Oaxaca have many white or pale yel- low spots on the dorsum. Individuals from the northern part of the range have small creamy white flecks on the flanks. In speci- mens from Colima and Michoacan the amount of white is increased on the flanks and tends to fuse into short, vertical bars and irregular spots. Individuals from the southern part of the range, Guerrero and Oaxaca, have much more white on the flanks; usually the flanks are marked by short, vertical white bars. In preservative, the dorsum is dull blue 86 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 24. Tadpole of Pachymedusa dacnicohr, L.A.C.M. No. 1808. x 3. or bluish gray; the venter is creamy white. The markings on the flanks and spots on the dorsum are dull creamy white. Tadpoles: A typical tadpole in develop- mental stage 34 has a body length of 17.2 mm. and a total length of 45.1 mm. The body is noticeably deeper than wide; it is deepest at a point about three-fourths of the length of the body. In dorsal profile the snout is trun- cate; in lateral profile it is acutely rounded. The nostrils are small, dorsolateral, directed anterolaterally, and situated at a point about two-thirds of the distance from the eyes to the tip of the snout. The eyes are relatively small and directed dorsolaterally. The spir- acle is ventral and sinistral to the midline; the spiracular opening is at a point about midway between the snout and the posterior edge of the body. The anal tube is short and dextral. The caudal musculature is moderately deep and gradually diminishes to a thin distal por- tion. The dorsal fin does not extend onto the body and is deepest at midlength of the tail; the ventral fin has an equal depth throughout the anterior half of the tail. Posteriorly both fins are considerably narrower. The depth of the caudal musculature at midlength of the tail is about equal to the depth of each of the fins (fig. 24). In life the tadpoles are bluish gray, except for the fins which are nearly transparent. In preservative, they are pale creamy tan with minute clusters of pigment on the dorsal sur- faces of the body and on the caudal muscu- lature; minute flecks are present on the fins. The mouth is moderately small, antero- ventral in position and directed anteriorly. Moderately deep lateral folds are present in the lips, which are bordered by a single row of papillae, except for the median third of the upper lip which is bare. Many papillae are present in the lateral fold. The beaks are moderately heavy and bear distinct serrations. The upper beak forms a broad arch with long, slender lateral processes. The lower beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows are long and extend laterally nearly to the papillae; the second upper row is interrupted medially. The lower rows are progressively shorter than the upper ones. In most indi- viduals, the lower rows are complete, but in some the first lower tooth row is narrowly in- terrupted medially ( fig. 25 ) . Mating Call: The call of Pachymedusa dacnicohr consists of a single note, resembling "cluck." The notes are repeated at intervals of a few seconds to several minutes. Each note has a duration of 0.16 to 0.36 (mean, 0.23) of a second and has a pulse rate of 120 to 190 (mean, 159) pulses per second. The fundamental frequency varies from 116 to 171 (mean, 153) cycles per second, and the ^"aiwyi^^a^Mj&ijt^^ Fig. 25. Mouth of tadpole of Pachymedusa dac- nicohr, L.A.C.M. No. 1808. X 12. 1970 DUELLMAN: HYLID FROGS 87 dominant frequency varies from 1120 to 2240 (mean, 1727) cycles per second (pi. 37, fig. 2). Natural History: Pachymedusa dacni- color inhabits xeric tropical lowlands char- acterized by a prolonged dry season. In this habitat of western Mexico, P. dacnicolor is one of the few amphibians that is active in the dry season. I have observed individuals perched on the branches of scrubby trees in the Balsas Basin in March and April. Hardy and McDiarmid (1968) noted that individ- uals of this species wore observed on roads in Sinaloa in the dry season. In the rainy season (June through October) males call from large herbs, bushes, or trees around temporary pools. Clasping pairs have been observed in trees and bushes. Usually the eggs are de- posited on leaves overhanging the water, but Taylor (1942a, p. 40) noted that on occasion the eggs are deposited on the ground a few inches above the water in pools where no trees or plants are present. Zweifel and Nor- ris (1955, p. 233) reported a mass of eggs on a grassy bank above the water in a small stream in Sonora. Duellman ( 1961c, p. 44) noted 100 to 350 eggs in each of 15 clutches at Coalcoman, Michoacan. The eggs are pale green and are located only in the exterior part of the clear gelatinous mass. Two composite egg masses were apparently made up of egg deposition on the part of three to five females. The tadpoles develop in shallow ponds where they swim freely, but take refuge amidst aquatic vegetation. In open water, the tadpoles orient with their heads up and the bodies forming an angle of about 45° with the surface of the water. Remarks: Sexual dimorphism in the shape of the snout is common among phyllomedu- sine frogs. Taylor (1952b) named Agalychn is alcorni and used the sexually dimorphic shape of the snout as the principle diagnostic char- acter of his new species. Funkhouser (1957) apparently was unaware of the significance of the shape of the snout and placed alcorni in a separate phyletic line from dacnicolor. Duellman ( 1957 ) demonstrated the sexual di- morphism in the shape of the snout in dacni- color and placed alcorni in the synonymy of dacnicolor. Etymology: The specific name dacnicolor apparently is derived from the Greek dacno, meaning bite or sting, and the Latin color; the meaning implied by Cope is not under- stood. Distribution: Pachymedusa dacnicolor in- habits xeric lowlands and lower montane slopes to elevations of about 1000 meters from southern Sonora to the Isthmus of Tehuante- pec, Mexico, including the Balsas Basin (fig. 26). See Appendix 1 for the locality records of the 862 specimens examined. Genus Agalychnis Cope Agalychnis Cope, 1864, p. 181 [no species desig- nated]; 1865a, p. 110 [H. morelctii, holochlora, and callidryas listed]. Taylor, 1952c, p. 801 [designation of Hyla moreletii Dumeril as the generotype]. Generotype: Hyla moreletii Dumeril, 1853, by subsequent designation (Taylor, 1952c). Most authorities, such as Smith and Taylor (1948), Funkhouser (1957), and Goin (1961b), gave Hyla callidryas Cope, 1862, as the generotype and the date of the genus as 1864" Cope (1864, p. 181) in his discussion of his new species, Phyllomedusa dacnicolor, stated in reference to dacnicolor: "It affords an easy passage to the true Hylae, whose fam- ily it enters, by the genus Agalychnis Cope, and H. moreletii and holochlora are the other species." It was not until the following year that Cope (1865a, p. 110) associated his Hyla callidryas with the genus Agalychnis; a foot- note to Agalychnis in his key to the genera of hylids contained the following statement: "Embraces Hyla moreletii, Dum., H. holo- chlora, Salvin, and H. callidryas, Cope." The determination of the availability of the generic name dating from 1864 rests on the interpretation of Cope's statement, "and H. moreletii and holochlora are the other spe- cies." It almost seems as though he forgot callidryas. However, his statement in the footnote (1865a, p. 110) clearly listed the species that he included in the genus. Be- cause Hyla moreletii is the first species listed in 1865, as well as in the noncommittal state- ment given in 1864, and because no specific designation of the generotype was made by Cope in either paper or in his subsequent writings, Hyla moreletii Dumeril, 1853, is the correct generotype, Cope (1864, p. 181) did 88 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 108° 104° 100° 96° SI 1 \ ,' 1 r \ / I \— "V. ' v (*■>. ... ' ) \ Vi \ S \ VA S '"*. A' '-■ \ \\ V • \ J --— v/ \ / \ ^ L\ 26° v.\ W^ r2 / f V \ • I < ■ / "• .-> 4 .■>■;■ 22° 22° \ • '"-■> ' ' / '■-'" l/-i ; <' ••% U-' • • v ;--:.j i 18° \.r • • •• A -J**2 c \ ^-^x • ^(r^ " ( s> 18° V •• ' \sS \ o 50 ioo 200 V^^ £ y | - | 1 1 ~^s.» -• S'l "'- KILOMETERS ^V. / i i ' 108° 104° 10°° 96° Fig. 26. Distribution of Pachymedusa dacnicolor. not mention Hyla callidryas; therefore the con- sideration of that species as the generotype by original designation, as given by Funkhouser (1957, p. 18) and others is erroneous. Etymology: The generic name is derived from the Greek aga, an intensive prefix, and the Greek, lychnis, a plant with scarlet flow- ers. Recause of the implied meaning of the generic name it seems likely that Cope was aware that the species known at that time had red eyes. Definition: Frogs of the genus Agahjch- nis are medium to large in size and have a green dorsum, variously colored flanks that are barred with contrasting colors in some species, and white, yellow, or orange venters. The pupil is vertical, and the iris is red or yellow. The palpebral membrane is reticu- lated in all except A. calcarifer. The fingers and toes are at least one-half webbed; the terminal discs are large. The first toe is shorter than the second and not opposable to the others. The vocal sac is single, median, and subgular. The skin on the dorsum is smooth; parotoid glands, if present, are poorly devel- oped. There is no integumentary-cranial co- ossification. The tongue is much longer than wide, extensively free posteriorly, and notched anteriorly and posteriorly. Rreeding males have horny brown nuptial excrescences on the thumbs. The skull is shallow, and the parietal plane slopes downward anteriorly; 1970 DUELLMAN: HYLID FROGS 89 the greatest depth of the skull is less than 40 per cent of the length. The skull is character- ized by a large frontoparietal fontanelle, weak quadratojugals (no bony attachment to max- illaries in some species), and moderately de- veloped squamosals having short anterior arms that do not extend more than one-half the distance to the maxillary. The premaxil- lary has a well-developed, posteriorly inclined alary process. The maxillary bears a moder- ately deep pars facialis, which at the level of the palatine extends dorsally and connects with the short maxillary process of the nasal. The nasals are large, narrowly separated me- dially, and separated from the sphenethmoid. The maxillary process of the nasal does not extend to the main axis of the maxillary, but connects with the posterior process of the pars facialis. The sphenethmoid is only moderately ossified. The dentigerous processes of the prevomers are short and situated at an angle to the midline. The pterygoids are robust but do not have a bony attachment to the prootics. The otic region is moderately small. Teeth are present on the premaxillaries, max- illaries, and prevomers, but absent from the palatines and the parasphenoid. The teeth are spatulate and strongly bifid, with a sug- gestion of a trifid condition in some. The known tadpoles are pelagic types and have mouths that are nearly terminal in position and directed anteriorly; the median part of the upper lip is bare; the rest of the mouth is bordered by two or three rows of papillae. The number of papillae is reduced to one row anterolaterally or medially on the lower lip in some species. The lips are slightly infolded laterally. There are two upper and three lower rows of teeth, and the second upper row is interrupted medially. The spiracle is ventral on the body and sinistral to the mid- line. The caudal musculature is slender, and the ventral fin is deeper than the dorsal fin. The mating call consists of a single or double note that is short and poorly modulated. The chromosome number is n=13 and 2n=26 (known only in A. calcarifer and caUidryas). Composition of Genus: Eight species are currently recognized. All are considered to be monotypic, although recognizable geographic variation occurs in Agalychnis caUidryas and spurrelli (see discussions in the accounts of those species). One species, Agalychnis cras- pedopus, does not occur in Middle America. Of the other seven species, 1437 preserved frogs, 43 skeletons, 62 lots of tadpoles, and 36 preserved clutches of eggs were examined from Middle America. Analysis of Characters: Agalychnis spur- relli is the largest species and saltator is the smallest; adult males of the former attain snout-vent lengths of 75 mm., and, of the latter, 46 mm. The largest specimen known is a female Agalychnis spurrelli having a snout-vent length of 92.8 mm. Females of all species are noticeably larger than the males and have slightly larger tympani. The sizes and proportions of the Middle American spe- cies are summarized in table 7. The taxonomically important external characters are principally those of the hands and feet. Webbing is least extensive in Aga- lychnis saltator, slightly more extensive in caUidryas, and much more extensive in annae, calcarifer, craspedopus, and moreletii; the hands and feet are fully webbed in litodryas and spurrelli (figs. 27-30). A dermal fold is present on the elbow and knee; this is elon- gated into a dermal flap in calcarifer. Exten- sive dermal flaps are present on the shank, heel, foot, and forearm of craspedopus. In calcarifer, calidryas, craspedopus, and salta- tor, the anal sheath is short, and the anal opening is directed posteroventrally at the level of the middle of the thighs. In the other species the sheath is long, and the anal open- ing is directed ventrally at the ventral sur- faces of the thighs. The color of, and the pattern on, the flanks and thighs are the most diagnostic features of the coloration (pis. 42 and 43). Agalych- nis litodryas is unique in lacking pigment on the anterior and posterior surfaces of the thighs and on the flanks. Agalychnis annae and saltator have uniformly blue flanks and thighs, whereas moreletii and spurrelli have uniformly orange-yellow flanks and thighs. Agalychnis calcarifer and craspedopus have orange flanks and thighs with dark vertical bars on both. The most variable species is caUidryas, in which the flanks vary from pale blue to dark blue or brown; all specimens have vertical or diagonal creamy yellow white bars on the flanks, and specimens from the 90 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 PL, c B - co W m < 'I B z 'pi ~5 — tJO o *c c — 'o CO B ft '3 J". 4-< — SO N B C C3 a, o U s G 2J £> M , -at/) TO 00 . C J .a P cy jg 3=3 co in _ t- ^ CO ^ CO CD O CO ^ 6 l": O CD O " in ^ ^ 10 l~ o "J. cm O CM O O t- O 00 6 *! ^ co «= cm ^ O O O O O CM O Tf ^ CD — t* -~_ o © d IO CO '"^CO a o . CM pi, CO ^ o co o 05 o CO © _ ^co — - li cm O CO I CO ^ CO CM © © t- © CO CM CM r— CO ' s CO ' "" CO ^"^ fe A © 1^ O l£ CM 2 9 o © -h © ^ <% IO CO ^ CO cJ, CO © 05 O 05 O © o CM ^_,CM ^_^CO o © © 00 CM ^ n. CO CO © ~ <$ © © © CM -—" CM Tf" O CO ■ co CO V co i co © *— I oo_;.-<^h;-j-i<1Jco 0©©CO©0©05 co co d Tf l> CD © — £; '--co dtof-d i Tt^ ' CO i CO — 'CO ^— 'CO © © © CO d o ^ © ^ CM CO o^c5© ©"©8 ~~- CO d So CM ~— 1C ^-^© I- « CD O S© ^co d o ^-.CM CO "* t; © CO i O CD -—-co d co o l^ CM 1> 00 ©^—. ©^-^tsl^-~.c^^^ • l-'J-:col^inco^Tt<^iol/::cD OitOHOHMOinoooct co^io^OT^^int^-^t^^ — lO^-iOCOOOCiOCDOlOO T}l -^ CO -— - •»# -— - "^ — - d odd d -in d 05 00 vaj ^H t- t- CD c^S ^S «•»? cS © § Jo ^ « ^d^co^^dgco^wg ^_- — ( ~_-Tf — - IO — -05^^00^-^ »n -* io co ■<*< in CM in ^h in 05 05 CO t- (M ^^ CM (a a Co Q _»,' ca o 2 <, <; 1970 DUELLMAN: HYLID FROGS 91 Fig. 27. Hands or three species ot Agalychnis. No. 96140. C. A. calcarifer, K.U. No. 77415. x 3. central part of the range have a longitudinal creamy yellow or white stripe separating the blue flanks from the green dorsum. The color of the thighs in callidryas varies from orange to blue. Small, round white spots are present on the dorsum of some specimens of all spe- cies except calcarifer, craspedopus, and lito- dryas. Most specimens of spurrelli have black- bordered white spots on the dorsum; this fea- ture of coloration seems to be unique to that species. The tadpoles of Agalychnis annae, calli- dryas, moreletii, saltator, and spurrelli are known. Of these, those of annae and more- letii are alike and differ from the others in having shorter tails and deeper bodies with slightly protruding snouts (fig. 31). The tad- poles of callidryas, saltator, and spurrelli are more slender and longer. In coloration and structure of the mouths, the tadpoles are nearly alike (fig. 32). The skulls of five species were studied; those of Agalychnis calcarifer, craspedopus, and litodryas were not examined. Interspecific differences exist in the shape and proportions of the skulls and in the proportions and degree of ossification of certain cranial elements ( figs. 33 and 34). The skulls of annae and moreletii are the deepest, whereas that of spurrelli is the shallowest, and those of callidryas and saltator are intermediate. The skull of spur- relli is further distinctive in lacking a bony articulation of the quadratojugal with the maxillary and in having only the posterior A. A. saltator, K.U. No. 103805. B. A. callidryas, K.U. part of the sphenethmoid ossified. The great- est amount of ossification of the sphenethmoid occurs in moreletii. The known mating calls (not known for calcarifer and craspedopus) consist of a sin- gle, or sometimes double note, which is re- peated at intervals of a few seconds to several minutes. The calls of Agalychnis litodryas and spurrelli are a low groan, which is noticeably lower in spurrelli than litodryas. The calls of the other species are shorter and have the energy spread through the frequency spec- trum; furthermore, in these species the last one, or several, pulses are intensified (table 8; pis. 38 and 39). Distribution: The combined distributions of the species of Agalychnis include the hu- mid forested lowlands and the humid lower montane forests from central Veracruz and southern Oaxaca, Mexico, southeastward throughout suitable habitats in Central Amer- ica onto the Pacific lowlands of South America to Esmeraldas Province in northwestern Ecua- dor. One species, A. craspedopus, is known only from the Amazonian lowlands of eastern Ecuador. Discussion : Prior to Funkhouser's ( 1957 ) revision of Plujllomedusa, most workers in the present century regarded all Central Ameri- can phyllomedusines, except Plujllomedusa lemur, to be members of the genus Agalych- nis. Funkhouser (1957) placed Agalychn is in the synonymy of Phyllomedusa; Goin ( 1961b) recognized Agalychnis and stated: "A recent 92 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 28. Hands of four species of Agalychnis. A. A. moreletii, K.U. No. 57942. B. A. annae, K.U. No. 64026. C. A. spurrelli, K.U. No. 77499. D. A. litodryas, K.U. No. 96149. x 3. 1970 DUELLMAN: HYLID FROGS 93 Fig. 29. Feet of three species of Agalychnis. A. A. saltator, K.U. No. 103805. B. A. callidryas, K.U. No. 96104. C. A. cakarifer, K.U. No. 77415. x 3. revision ( Funkhouser, 1957 ) includes Aga- lychnis in Phyllomedusa, but the arguments for doing so do not to me seem convincing." Duellman (1968b) recognized Agalychnis as distinct from PhyUotnedusa and proposed that Agalychnis dacnicolor be placed in a separate genus, Pachymedusa. Within the genus Agalychnis, as now recog- nized, the species can be grouped in four pairs — saltator and callidryas, moreletii and an- nae, calcarifcr and craspedopus, spurrelli and litodryas. According to Funkhouser's ( 1957 ) phylogenetic scheme, moreletii and spurrelli are primitive, whereas saltator and callidryas are advanced. Funkhouser attempted to ex- plain the evolution of the species of Phyllo- medusa by assuming that they evolved from an advanced Hyla-Mke ancestor. Therefore, she placed those species having large fully webbed hands and feet near the base of her phylogenetic scheme and hypothesized that in its evolution the group passed through stages of reduction and eventual loss of web- bing to the development of grasping toes. Duellman ( 1968b ) suggested that the evolu- tion of extensive webbing and large adhesive discs probably was not reversed so as to re- sult in generalized hands and feet, from which evolved another kind of arboreal adaptation, the grasping opposable digits. A more reason- able hypothesis is that the evolution of op- posable digits took place in a phyletic line that had as its ancestral stock a frog with generalized hands and feet. If this assump- tion is correct, Phyllomedusa and Agalychnis represent two phyletic lines; each evolved in- dependently from a generalized stock, prob- ably not unlike the existing Pachymedusa. It is obvious that saltator and callidryas are the least specialized species. They have the least modified skulls, the most generalized hands and feet, and lack dermal appendages on the limbs. Agalychnis moreletii and an- nae probably were derived from a saltator- like ancestor and differentiated from one another through isolation — moreletii in the mountains of nuclear Central America and annae in the mountains of lower Central America. The calcarifer-craspedopus line probably evolved through isolation in South America from the main Agalychnis stock in Central America. The isolated position of craspedopus on the eastern side of the Andes suggests that the calcarifer-craspedopus stock occupied lowlands on both sides of the moun- tains. Subsequent differentiation resulted in craspedopus in the Amazonian region and calcarifer on the Pacific lowlands. Agalychnis calcarifer is probably a recent immigrant into lower Central America. Too little is known of the geographic range of litodryas to even guess about its differentiation from spurrelli. The phylogeny of the species of Aga- lychnis proposed here assumes a generalized 94 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 30. Feet of four species of Agalychnis. A. A. morelctti, K.U. No. 57942. B. A. annae, K.U. No. 64026. C. A. spurrelli, K.U. No. 77499. D. A. Htodnjas, K.U. No. 96149. x 3. 1970 DUELLMAN: HYLID FROGS 95 Fig. 31. Tadpoles of five species of Agalychnis. A. A. saltator, K.U. No. 110130. B. A. callidryas, K.U. No. 77630. C. A. spurrelli, K.U. No. 104309. D. A. annae, K.U. No. 91806. E. A. moreletii, K.U. No. 60014. X 2. hylid ancestral stock having only moderately webbed hands and feet, short anal sheath, and small tympanum, and lacking contrasting markings on the flanks and thighs and dermal appendages on the limbs. From this prototype developed frogs with more extensive webbing and longer anal sheaths. The long anal sheath directed ventrally at the lower level of the thighs possibly is an adaptation for more effi- cient deposition and fertilization of eggs on leaves. Since blue is a structural color result- ing from the absence of lipophores above the guanophores, it is reasonable to assume that blue is a derived color in Agalychnis. Thus, we can assume that the ancestral Agalychnis probably had yellow flanks. Starrett's (1960a) description of the ontogenetic development of color pattern in A. callidryas provides evi- dence that the basic colors on the flanks are developed first and that these are followed by the markings. If this is true phylogeneti- cally, as well as ontogenetically, the pattern on the flanks of callidryas could have been derived from an ancestral stock colored like saltator and the pattern on the flanks of cal- carifer and craspedopus could have been de- rived from an ancestral stock colored like spurrelli. 96 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 «00i t>0 :?^,n,w''««%,.\ ^^..^'""'BniitiainiiiiiiinttW'"',,.,:. <>nunilUliliii ,^"''«nmI,,lu,1'"''•«'*"''l»ll?!!!wM'l,,rl^ci• S~^i"""'l'l,"»IMilliiall»imilH"|M L- ^wHuniiiiiiiiin,,,,^ ^mifmillliiillllllliiWMft^ ^^vv»iHHuuniiiii\iI(1(0lWiMf„ll,,j,l|iiii,iiiiiMiiiiimwi,lr/,/^<*« v «««wt«ni'rirtnninnimiMi(MiniiinnmHnnft««N»»^J^ Fig. 32. Mouths of three species of tadpoles of Agalychnis. A. A. caUidnjas, K.U. No. 77630. B. A. spurrelli, K.U. No. 104309. C. A. a/uiae, K.U. No. 91806. X 15. 1970 DUELLMAN: HYLID FROGS 97 Fig. 33. Dorsal ( A ) , ventral ( B ) , and lateral ( C ) views of the skull of Agalychnis callidrtjas, K.U. No. 104358. X 5. 98 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 34. Dorsal and lateral views of the skulls of two species of Agalychnis. A and C. A. spurrelli, K.U. No. 77663. B and D. A. moreletii, K.U. No. 59852. X 3. TARLE 8 Characteristics of the Mating Calls, with Means in Parentheses, of the Species Agalychnis. Species N A. annae 13 A. caUiclnjas 25 A. litodnjas 1 A. moreletii 8 A. saltator 2 A. spurrelli 2 Duration ( seconds ) Pulses per Second Fundamental Frequency (cps) Dominant Frequency (cps) 0.16-0.44 38-50 140-185 1044-1295 (0.31) (42) (161) (1165) 0.08-0.24 180-200 165-200 1488-2400 (0.16) (189) (182) (1975) 0.15 105 104 1664 0.09-0.27 55-61 160-185 1110-1260 (0.13) (58) (172) (1171) 0.08-0.12 105-110 114-126 1844-1890 (0.10) (108) (120) (1867) 0.34-0.40 60-90 87-100 435-700 (0.37) (75) (94) (568) 1970 DUELLMAN: HYLID FROGS 99 Agalychnis saltator Taylor Apalychnis saltator Taylor, 1955, p. 527, fig. 10 [holotype, K.U. No. 35615 from "4 km. NNE Tilaran, Guanacaste, Costa Rica"; type locality according to collector's field notes and museum catalogue is Finca San Bosco, 5 kilometers north-northeast of Tilaran (fide Duellman and Berg, 1962, p. 189); Edward H. Taylor collector]. Duellman, 1968b, p. 4. Phyllomcdusa saltator: Funkhouser, 1957, p. 36 [transfer of Agalychnis saltator Taylor, 1955, to Phijllo- medusa Wagler, 1830], Diagnosis: This small species of Agalych- nis has a dark red eye; the fingers are about one-third webbed, and the toes are about one-half webbed. It differs from all other species in the genus, except annae, by having uniformly dark blue or purple flanks and thighs. Furthermore, the dorsum by day is green, with narrow, transverse, darker green lines and at night reddish tan with brown transverse lines. In annae, which is much larger, the dorsum is uniformly green by day and night, the eye is orange, and the fingers and toes are about two-thirds webbed. Struc- turally saltator is similar to caUidryas, but it lacks the vertical white or cream-colored bars on the flanks that characterizes that species and has less webbing on the hands and feet (figs. 27 and 28). Agalychnis caUidryas does not have a tan dorsum at night. Although some caUidryas have dark green transverse lines on the dorsum, this species can be dis- tinguished readily from saltator in that caUi- dryas has orange thighs and vertical cream- colored bars on the flanks. Description: Agalychnis saltator is the smallest species in the genus; males attain a maximum snout-vent length of 46.7 mm. (mean, 19 specimens, 42.5 mm.), and females reach 61.5 mm. (mean, five specimens, 57.0 mm.). In a sample of 10 males from Puerto Viejo, Heredia Province, Costa Rica, the ratio of tibia length to snout-vent length is 0.486 to 0.527 (mean, 0.509); the ratio of foot length to snout-vent length is 0.350 to 0.382 (mean, 0.367); the ratio of head length to snout- vent length is 0.304 to 0.337 (mean, 0.325); the ratio of head width to snout- vent length is 0.293 to 0.327 (mean, 0.311), and the ratio of the diameter of the tympanum to that of the eye is 0.448 to 0.555 ( mean, 0.483) . Females have proportionately larger tympani; tlie tympanum/eye ratio in five females from Puerto Viejo is 0.535 to 0.634 (mean, 0.583). The head is slightly wider than the body, and the top of the head is flat. In dorsal pro file the snout is narrowed and acuminate. In lateral profile, in males, the snout is gently sloping from the eyes to the nostrils and fur- ther inclined to the tip of the snout; in fe- males, the snout anterior to the nostrils is bluntly rounded. The nostrils are slightly pro- tuberant and are situated at about three- fourths the distance from the eyes to the tip of the snout. The canthus is rounded and distinct; the loreal region is slightly concave, and the lips are thin and slightly flared. A dermal fold extending from the posterior corner of the eye to a point just posterior to the angle of the jaw conceals the upper and posterior edges of the tympanum. The fold continues as a flap of skin to a point above the insertion of the arm. The tympanum is distinct and situated posterior to the lower one-half of the eye. The tympanum is sepa- rated from the eye by a distance equal to about one-half the diameter of the tympanum. The upper arm is slender, and the forearm is moderately robust. A narrow dermal fold extends across the elbow and along the ventro- lateral edge of the forearm to the disc on the fourth finger. The fingers are moderately short and slender and have large discs; the diameter of the disc on the third finger is slightly larger than that of the tympanum in females and about half again as large in males. The subarticular tubercles are small and round, except the distal tubercle on the fourth finger which is larger, flat, and barely bifid in some specimens. The pollex is slightly enlarged and in breeding males bears a horny nuptial excrescence composed of minute spinules. The fingers are about one-half webbed (fig. 27A). The webbing is barely evident between the first two fingers but connects the base of the penultimate phalanx of the second finger to the base of the ante- penultimate phalanx of the third. The web extends from the distal part of the antepen- ultimate phalanx of the third finger to the base of the penultimate phalanx of the fourth. The hind limbs are slender; the adpressed heels overlap by about one-third of the length of the shank. The tibiotarsal articulation 100 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 extends to the anterior corner of the eye. A narrow dermal fold extends along the median edge of the shank, across the heel, and along the ventrolateral edge of the tarsus to the disc on the fifth toe.A weak tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is moderately large, flat, and ovoid. The toes are slender, and the terminal discs are slightly smaller than those on the hands. The sub- articular tubercles are small and round. Su- pernumerary tubercles are present on the proximal segments of all but the first toe. The toes are about three-fourths webbed (fig. 28A.) The web connects the first two toes at the level of the bases of the penultimate phalanges and extends from that point on the second toe to the base of the antepenultimate phalanx of the third toe. From the base of the penultimate phalanx of the third toe the web extends to the base of the antepenulti- mate phalanx of the fourth toe and from the middle of the antepenultimate phalanx of the fourth toe to the base of the penultimate pha- lanx of the fifth. The anal sheath is short. The anal opening is directed posteroventrally at the level of the middle of the thighs. The skin of the dorsum, chin, chest, and ventral surfaces of the limbs, except proximally on the thighs, is smooth, whereas that on the belly and proximal sur- faces of the thighs is granular. A row of large granules extends along the posteroventral edge of the thighs. The tongue is about half again as long as wide, notched anteriorly and posteriorly, and free behind for about one- third of its length. The dentigerous processes of the prevomers are posteromedially inclined ridges between the posterior margins of the long, elliptical choanae. Males have three to five teeth on each process and a total of seven to 10 (mean, 8.6) prevomerine teeth, whereas females have four to six teeth on each process and a total of nine to 12 (mean, 10.6) pre- vomerine teeth. The vocal slits are situated between the posterolateral corners of the tongue and the angles of the jaws. The vocal sac is single, median, subgular, and not greatly distensible. The general coloration by day is green above with blue flanks and thighs or by night, reddish brown above with blue flanks and thighs (pi. 42, figs. 1 and 4). Ry day most individuals are pale green with or with- out darker green transverse lines on the dor- sum and limbs. The flanks and anterior and posterior surfaces of the thighs are purplish blue. The hands, feet, and ventral surfaces of the limbs are pale orange; this color ex- tends onto the anterior and posterior surfaces of the thighs in some males. The throat and anal area are white, and the belly is creamy white. The iris is coppery red, and the palpe- bral membrane has gold reticulations. In breeding males, the nuptial excrescence is brown. At night the dorsum is reddish tan with brown transverse markings, olive-tan with dark olive-green markings, or dull green with darker green markings. Some specimens have pale yellow spots, narrowly outlined with black on the dorsum. In preservative, the ventral surfaces are white and the flanks and anterior and pos- terior surfaces of the thighs are dull purple. The dorsum is pinkish brown to dull blue with darker transverse lines. The dorsal markings are more evident in preserved speci- mens than in most living individuals. Small white flecks are present on the lower flanks of many specimens, and a small white spot is present at the posterior corner of the eye in some specimens. Tadpoles: Four tadpoles in developmental stage 28 from Puerto Viejo, Heredia Province, Costa Rica, have body lengths of 9.6 to 10.4 (mean, 10.1) mm., and total lengths of 28.0 to 30.5 (mean, 29.6) mm. Three tadpoles in developmental stage 32 from the same locality have body lengths of 10.8 to 11.5 (mean, 11.1) mm. and total lengths of 33.0 to 36.2 (mean, 34.3) mm. In these specimens the tail length/ total length ratio is 0.652 to 0.682 (mean, 0.665). A tadpole in developmental stage 34 has a body length of 13.8 mm., a total length of 40.2 mm., and a tail length/ total length ratio of 0.633. The body is slightly wider than deep; it is widest and deepest posteriorly. The snout in dorsal profile is truncate; in lateral profile the snout slopes gradually from the eyes to the bluntly rounded tip. The nostrils are dorsolateral, about one-third of the dis- tance from the snout to the eyes, and directed anteriorly. The eves are dorsolateral and di- 1970 DUELLMAN: HYLID FROGS 101 rected laterally. The diameter of the eye equals about one-fourth of the greatest depth of the body. The spiracle is ventral and sinis- tral to the midline; the spiraeular opening is at a point about midlength of the body. The mouth is anteroventral and directed anteri- orly. The cloacal tube is short and dextral to the caudal fin. The caudal musculature is slender and distally tapered. The depth of the caudal musculature at midlength of the tail is slightly more than the depth of the dorsal fin and noticeably less than the depth of the ventral fin. The dorsal fin is deepest at midlength of the tail and does not extend onto the body. The ventral fin is noticeably deeper than the dorsal fin, has about an equal depth on the anterior two-thirds of the tail, and narrows posteriorly (fig. 31A). The mouth has a shallow lateral fold. The median part of the upper lip is bare. One or two rows of papillae are present on the rest of the lips. Additional papillae are present in the lateral fold. The upper beak is moder- ately robust with slender lateral processes. The lower beak is slender and broadly V- shaped. Both beaks have well-developed ser- rations. There are two upper and three lower rows of teeth. The two upper rows are about equal in length and extend nearly to the lips; the second row is narrowly interrupted me- dially. The lower rows are progressively shorter from the first to the third; the latter is narrowly interrupted medially. In preservative the body is pale gray; the caudal musculature is creamy white. Gray reticulations are present on the caudal muscu- lature and fins. Mating Call: The call of Agahjchnis sal- tator consists of a single, or sometimes double, "clack" repeated at intervals of about 30 sec- onds to several minutes. Analysis of two calls shows that the duration of the notes is 0.08 and 0.12 (mean, 0.10) of a second. The notes have a pulse rate of 105 and 110 (mean, 108) pulses per second. The fundamental fre- quency is at 114 and 126 (mean, 120) cycles per second, and the dominant frequency is at 1844 and 1890 (mean, 1867) cycles per sec- ond (pi. 38, fig. 1). Natural History: Agahjchnis saltator in- habits lowland tropical rain forests where it breeds in temporary and permanent ponds. Calling males were found at Finca San Bosco, Guanacaste Province, Costa Rica, in August, and calling males and clasping pairs were found at Puerto Viejo, Heredia Province, Costa Rica, in June. At all localities where Agahjchnis saltator is known, A. callidryas also occurs. Remarks: Two specimens from Eden Mine, Zelaya Province, Nicaragua (A.N.S.P. Nos. 21131 and 21132), and one from La Castilla, Limon Province, Costa Rica (A.N.S.P. No. 23810) have been misidentified as Agahjchnis callidryas. All three specimens are clearly saltator as evidenced by the small amount of webbing, dark transverse lines on the dorsum, and absence of white vertical bars on the flanks. Etymology: The specific name saltator is Latin and means leaper. Distribution: The range of Agahjchnis saltator extends through the humid Caribbean lowlands from northeastern Nicaragua to 86° 84° 1 .J '- „ -> r I i j 14° f # * \ 14° 10° 0 50 200 N^ 10° KILOMETERS \ ^\_ \ | *, 1 1 » 86° 84° Fig. 35. Distribution of Agahjchnis saltator. 102 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 northeastern Costa Rica (fig. 35) where it oc- curs on the lowlands and on the lower Carib- bean slopes of the highlands to elevations of 780 meters. See Appendix 1 for the locality records of the 53 specimens examined. Agalychnis callidryas (Cope) Hyla callidryas Cope, 1862, p. 359 [holotype, A.N.S.P. No. 2091 from Darien, Panama; Captain Field collector; type locality unjustifiably restricted to Cordoba, Veracruz, Mexico, by Smith and Taylor (1950, p. 347)]. Agalychnis callidryas Cope, 1865a, p. 110 [trans- fer of Hyla callidryas Cope to Agalychnis Cope, 1864]. Boulenger, 1882a, p. 423. Gunther, 1901 (1885-1902), p. 290. Smith and Taylor, 1948, p. 72. Taylor, 1952c, p. 807. Duellman, 1968b, p. 4. Agalychnis hclenae Cope, 1885a, p. 182 [holotype, U.S.N.M. No. 13737 from "Nicaragua"; J. F. Moser collector]. Gunther, 1901 (1885-1902), p. 290. Tay- lor, 1952c, p. 805. Phyllomedusa hclenae: Kellogg, 1932, p. 145 [transfer of Agalychnis hclenae Cope, 1885a, to Phyl- lomedusa Wagler, 1830]. Funkhouser, 1957, p. 32. Phyllomedusa (Agalychnis) callidryas: Lutz, 1950b, p. 601 [transfer of Hyla callidryas Cope, 1862, to Phyllomedusa Wagler, 1830]. Phyllomedusa callidryas callidryas: Funkhouser, 1957, p. 33. Phyllomedusa callidryas taylori Funkhouser, 1957, p. 34 [holotype, E.H.T. No. 1279 from Tierra Colo- rada, Veracruz, Mexico; Edward H. Taylor, and Hobart M. Smith collectors]. Stuart, 1963, p. 38. Phyllomedusa callidryas: Savage and Heyer, 1967, p. 123 [synonymized Agalychnis helenac Cope, 1885a, and Phyllomedusa callidryas taylori Funkhouser, 1957, with Phyllomedusa callidryas (Cope, 1862)]. Diagnosis: This moderate-sized species is distinguished from all other species of Aga- lychnis by having dark flanks with pale verti- cal bars. The flanks are usually blue, but are brown in some populations, and the vertical bars are white or creamy yellow. The anterior and posterior surfaces of the thighs are uni- color blue or orange. The only other species having vertical bars on the flanks are A. cal- carifer and craspedopus, which have orange flanks with black bars; furthermore, both of these species have dark bars on the thighs. Agalychnis annae and saltator have uniformly blue flanks lacking vertical bars. Description: Agalychnis callidryas is a moderate-sized, slender species; males attain a maximum snout-vent length of 56 mm., and females reach 71 mm. The size attained by adults of both sexes varies geographically; in general, specimens from the northern part of the range (Mexico and Guatemala) are the smallest, and those from Nicaragua are the largest (table 9). In a sample of 26 males from Cerro La Campana, Panama Province, Panama, the snout-vent length is 44.5 to 50.9 (mean, 47.9) mm., the ratio of tibia length to snout- vent length is 0.477 to 0.532 (mean, 0.510); the ratio of foot length to snout- vent length is 0.340 to 0.386 (mean, 0.363); the ratio of head length to snout-vent length is 0.312 to 0.344 (mean, 0.328); the ratio of head width to snout-vent length is 0.320 to 0.368 (mean, 0.334), and the ratio of the diameter of the tympanum to that of the ,eye is 0.444 to 0.596 (mean, 0.525). Seven females from the same locality have snout-vent lengths of 54.4 to 66.1 (mean, 62.8) mm. In proportions they differ from the males only in having larger tympani; the tympanum/eye ratio in the females is 0.516 to 0.620 (mean, 0.585) per cent. Little geographic variation in pro- portions is evident, except that specimens from extreme eastern Panama have slightly narrower heads (table 10). The head is slightly wider than the body, except in gravid females, and the top of the head is flat. In dorsal profile the labial border is rounded, and the snout is truncate. In lat- eral profile, in males, the snout is gently slop- ing from the eyes to the nostrils and then sharply angled to the snout; in females, the snout anterior to the nostrils is truncate. The nostrils are distinctly protuberant and are situated about four-fifths the distance from the eyes to the tip of the snout in males and even closer to the tip of the snout in females. The canthus is broadly rounded and barely distinct; the loreal region is slightly concave, and the lips are thin and not flared. A thin dermal fold extends posteroventrally from the posterior corner of the eye, covering the upper and posterior edges of the tympanum, to a point just posterior to the angle of the jaw. A heavy dermal flap extends from this point to a point above the insertion of the arm. The tympanum is distinct, situated pos- terior to the eye, and separated from the eye by a distance equal to about one-half of the diameter of the tympanum. 1970 DUELLMAN: HYLID FROGS 103 o s k= o « 60 3 < CD -s — s h3 a, cs 60 O c v ^Ck •5 2 CO « c Ck a; 60 cd 60 cd 60 a) CD m CD cd -a § Mm cd CD 60 CD 60 a a C 3 3 3 3 3 3 3 3 3 3 cS CS CS 11 C8 CD CS 0 1-. o o 04 m m 03 03 3 ^ 03 03 w 03 3 ii 3 i-i 03°03° o o CD CD s s CD _3 5 03 CD J3 03 03 03 CD _3 5 030303 (DsTco^CD^CJ^' 3S3S3S32 CD _3 paO3pqO3pqO3p303 03 c 03 00 0 CD in CC CO t~ CM t^ t t^ CC a? c» X m CO 05 1 — 1 t~ CO in CO ~r CO *r CO in cm -* CO -r -r in ■* in -* in r^ X i-~ x CO in *r CD 3> CO CD CO ^ScocDcq^asincoScoo 2 a> op co 2 >"- 3 _^ -^ CM CM CM CM CM CO -i t--" ■-- < -LC35-4 03 , CT> co csi in t- CM CD cdco.SoicdO^cd^-1 t-— • j t-- fi. 0 , A in -,j 10 ,i in ^m^in^in^cD «5 CD <*! a> ^-1— i^oq^-'co^-^ CT> -— ,CD in in in cd m cd in in t-gcocgcogcooq °C i rA CM' ' CO ,J CT) CM - — -in ^-f — -rt< — - in co m h in cB^g^ ^ « rA n in CD CO -CM CD CD as t> CO t> O CO CO 05 o *, 00 °g ST g w SS ^TS w g cq £ 3TS aj S3 ^. Jo" *? S « S STS w ^ ^ ® !§ 06 5 co. g rt tgco^p^p^in^^^in^in^^^ 05^ — 'co^^c*<-_^cd- — -in^— -in- — -■* -— 'i-h -^ CO-tfCOT) -J p ju 03 < .2 " H o w a~ o ^ J-1 -o P"< G mh •3 o ^-< ^ hi QJ Co — u & M-i C o cd c^ O Co in > "as a c o U s H 0) 60 . "8 m ■3 in o i—i cd co TO __ © ._ CT> . . CT> . . t-- . . OcMOcMOoOcMOco d10. ^^d^^^co1^ 10000000^0050 o o o d d m > - _: in _; CO _: CM O ,_( O o O -~^co — 'CO — d d 3? ogd 'CO ^ d co t- o co co t— ^CD ^—.00 ^-^oo ^-^t— ,—. omoinocDocoom i CO'CO'CO'CO'CO i— l_J^f_;in_;0_;CO^ coOTfO^OTfOcoO CO "— 'CO — 'CO"— 'CO-—- CO' — • d d d d d Oi CO t— CM CO i— i^co,^cD„.co^in,^ "3 o^in "? w»^ irV OOO.— lOcOOi— lOcM d « eii « 05 « t^- »» cm ^ CDOOOO^Ot^OOO tj< — -rt< — m — -■»*< - — -m — • d d d d d c& CM CI c CO •w CS 3 o c" -CO QJ a w bo o CJ o o H ctf o 2 o U OS o 2 o U c o 'So CO "3 Q o O S ctf C as a a! a £ OS U OS CO U -as S Q o 1970 DUELLMAN: HYLID FROGS 105 The upper arm is slender, and the lower arm is moderately robust. A thin dermal fold crosses the elbow and extends along the ven- trolateral edge of the forearm to the disc of the fourth finger. The fingers are short and have moderately large discs; the diameter of the disc on the third finger is equal to, or slightly larger than the tympanum. The sub- articular tubercles are large and round, ex- cept the distal tubercles on the third and fourth fingers are flattened; the distal tubercle on the fourth finger is bifid in many speci- mens, and that on the third finger is bifid in many specimens. The pollex is enlarged, and in breeding males bears a nuptial excrescence composed of many horny spinules. The fin- gers are about one-half webbed (fig. 27B). The webbing extends from the base of the penultimate phalanx of the first finger to the middle of the antepenultimate phalanx of the second, and from the base of the penultimate phalanx of the second finger to the middle of the antepenultimate phalanx of the third. The webbing connects the third and fourth fingers between the distal ends of the ante- penultimate phalanges. The hind limbs are slender; when the hind limbs are adpressed, the heels overlap by about one-third the length of the shanks. The tibiotarsal articula- tion extends to a point between the eye and the tip of the snout. A thin dermal fold crosses the heel and extends along the outer edge of the tarsus to the disc on the fifth toe. The tarsal fold is weak, but extends the full length of the tarsus. The inner metatarsal tubercle is large, slightly rounded, and ovoid. The toes are relatively short and slender; the terminal discs are nearly as large as those on the hand. The subarticular tubercles are small and round. The toes are about two-thirds webbed (fig. 28B). The webbing connects the first and second toes at the bases of the penultimate phalanges and extends from the base of the penultimate phalanx of the second toe to the base of the antepenultimate phalanx of the third. From the middle of the pen- ultimate phalanx of the third toe the web extends to the base of the antepenultimate phalanx of the fourth, and from that point it continues to the base or middle of the penulti- mate phalanx of the fifth toe. The anal sheath is short, and the anal opening is directed posteroventrally at the level of the middle of the thighs. The skin of the dorsum, chin, and ventral surfaces of the limbs, except the thighs, is smooth; the skin of the belly and ventral surfaces of the thighs is granular. The tongue is twice as long as wide, notched anteriorly and pos- teriorly, and free behind for nearly one-half of its length. The dentigerous processes of the prevomers are posteromedially inclined ridges between the posterior margins of the elliptical ehoanae. Males have four to six teeth on each process and a total of eight to 11 (mean, 9.7) prevomerine teeth. Fe- males have six to eight teeth on each process and a total of 12 to 16 (mean, 14.0) prevo- merine teeth. The vocal slits lie along the inner posterior margin of the jaw. The vocal sac is single, median, subgular, and not noticeably distensible. The general coloration consists of a green dorsum, creamy white venter, and dark flanks with vertical or diagonal creamy yellow bars (pi. 42, figs. 2 and 5). The dorsal surfaces of the head, body, hind limbs, forearm, fourth fingers, and fifth toes are leaf green, varying in some individuals to darker green. Some specimens, especially those from Nicaragua and Costa Rica have faint, narrow, dark green transverse lines on the dorsum. The throat and belly are creamy white. The hands and feet, with the exception of the outer digits on each, are orange. A white line is present on the outer edge of the tarsus and on the outer edge of the forearm. In some specimens from Nicaragua and the Caribbean lowlands of Costa Rica a thin white line usually is present on the edge of the upper eyelid. The iris is red, and the palpebral membrane is reticulated with gold; the nuptial excrescences are dark grayish brown. The colors of the flanks and thighs, and the pattern on the flanks varies geographically (fig. 36, table 9). The general trend in varia- tion is an increase in the numbers of bars on the flanks from north to south. For example, 69 specimens from Oaxaca and Veracruz, Mexico, have 3 to 8 (mean, 5.0) bars on each flank, whereas 50 specimens from Darien Province, Panama, have 6 to 13 (mean, 9.0) bars. In most specimens from Mexico south- eastward to Bocas del Toro Province, Panama, 106 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 PATTERN Fig. 36. Flank patterns in Agalychnis callidnjas (somewhat diagrammatic). Pattern 2. K.U. No. 103786. Pattern 4. K.U. No. 77434. Pattern 6. K.U. No. 77456. Pattern 8. K.U. No. 77441. Pattern 10. K.U. No. 77494. the cream bars are broader than in those specimens from the Golfo Dulce region of Costa Rica and from central and eastern Panama, although in some individuals the bars are narrow. In the middle part of the range (Caribbean lowlands of Nicaragua and Costa Rica) the dark blue flanks are sepa- rated from the green dorsum by a longitudinal creamy yellow line, which in most specimens connects the upper edges of the vertical bars. This longitudinal stripe is absent in specimens from the northern part of the range (Mexico southward through Honduras) and from the south (Panama and Pacific lowlands of Costa Rica). In some specimens from the middle part of the range the longitudinal stripe either is discontinuous or is not fused with all of the vertical bars. The variation in pattern on the flanks (fig. 36) was coded, and the ranges and mean values for 15 samples were calculated (table 9). In some specimens, the pattern on the left and right flanks were different; in these cases an intermediate value was assigned. For example, a specimen having pattern 2 on one flank and pattern 4 on the other was given a value of 3. Examination of table 9 reveals that the lowest values (greatest number of specimens having pattern 2) occur in Nica- ragua and the Caribbean lowlands of Costa Rica. In either direction the values increase to, or near to, pattern 10. In addition to pattern, the color of the flanks varies geographically. In Mexico and Guatemala the flanks are pale blue to dark blue, and in Nicaragua and the Caribbean lowlands of Costa Rica and western Panama the flanks are dark blue to purple. On the Pacific lowlands of Costa Rica and in central Panama (Cerro La Campana and Canal Zone) the flanks are dull blue to purplish brown, and in eastern Panama they are brown. The anterior and posterior surfaces of the thighs, and the ventral surfaces of the thighs and shanks are dark blue in specimens from Nicaragua and the Caribbean lowlands of Costa Rica, whereas elsewhere in the range these surfaces are predominantly orange. Some specimens from Rocas del Toro Prov- ince, Canal Zone, and Cerro La Campana, Panama Province, in Panama have some blue proximally on the anterior and posterior sur- 1970 DUELLMAN: HYLID FROGS 107 faces of the thighs; otherwise, the thighs are orange. Small white spots are present on the dor- sum of the body in many specimens. In those specimens having spots, the number of spots varies from 1 to 22. The percentage of indi- viduals having spots varies from 44 to 62 in three samples from the northern part of the range (eastern Mexico, Guatemala, and Hon- duras) and from 42 to 75 in Nicaragua and the Caribbean lowlands of Costa Rica the per- centage varies from zero to 30. Although the majority of specimens from Nicaragua and the Caribbean lowlands of Costa Rica lack white spots, 16 per cent of the 169 specimens from that region have five white flecks on the dorsum. In preservative the dorsum is blue, and the venter is white. The flanks are dark blue or lavendar with white bars. The thighs are blue or creamy white. Tadpoles: Seven hatchling tadpoles from Toocog, El Peten, Guatemala, have total lengths of 7.2 to 7.8 (mean, 7.4) mm., and four hatchlings from 22 kilometers south of Managua, Nicaragua, have total lengths of 11.4 to 12.7 (mean, 12.1) mm. Nine tadpoles in stages 27 to 32 from Toocog have body lengths of 8.7 to 9.3 (mean, 9.1) mm. and total lengths of 21.8 to 26.1 (mean, 23.4) mm., whereas 12 tadpoles in the same develop- mental stages from Barro Colorado Island, Panama, have body lengths of 14.7 to 17.9 (mean, 16.1) mm. and total lengths of 31.0 to 40.2 (mean, 36.9) mm. Two tadpoles in stage 41 from Barro Colorado Island, Panama, have body lengths of 17.5 and 19.3 mm. and total lengths of 48.0 and 53.0 mm. A typical tadpole in developmental stage 34 has fully developed mouth parts but has undergone no external changes, except for the development of limb buds (fig. 31B). The body is slightly deeper than broad. It is deep- est posteriorly and widest just behind the eyes. The snout in dorsal profile is truncate; in lateral profile it is acuminate and slightly dorsal to the midline. The nostrils are dorso- lateral, about one-third of the distance from the snout to the eyes, and directed anteriorly. The eyes are dorsolateral and directed lat- erally. The diameter of the eye equals about one-fourth of the greatest depth of the body. The spiracle is ventral and sinistral to the midline; the spiracular opening is at a point about midlength of the body. The mouth is anteroventral and is directed anteriorly. The cloacal tube is short and dextral to the caudal fin. The caudal musculature is slender and distally gradually tapers nearly to reach the tip of the fin. The depth of the musculature at midlength of the tail is slightly more than the depth of the dorsal fin and about equal to one-third of the depth of the tail. The dorsal fin is deepest at midlength of the tail and does not extend onto the body. The ven- tral fin is noticeably deeper than the dorsal fin, has about equal depth on the anterior two- thirds of the tail, and narrows posteriorly. The mouth has a shallow lateral fold. The median part of the upper lip is bare; lateral to the bare part of the upper lip and on the median part of the lower lip one row of pa- pillae is present. Otherwise, two or three rows of papillae are present on the lips. Lat- erally, additional papillae are medial to the fringing papillae. The upper beak is moder- ately robust and forms a broad arch; the lateral processes are slender and barely ex- panded distally. The lower beak is rather slender. Both beaks have well-developed, blunt serrations. There are two upper and three lower rows of teeth. The two upper rows are about equal in length and extend nearly to the papillae; the second row is in- terrupted medially. The lower rows are con- tinuous; the first and second rows are nearly as long as the upper rows, whereas the third row is slightly shorter (fig. 32B). The snout, top of head, and dorsolateral surfaces of the body are olive-gray; the sides and venter are bluish gray with olive-brown flecks. In some tadpoles, the belly has a golden cast. The caudal musculature is gray- ish tan and the caudal fins are transparent; both are flecked with dark gray. In late stages the dark pigment expands to form bold re- ticulations on the tail and a uniform olive- brown dorsum. The iris is bronze. The most noticeable variation in tadpoles is in the arrangement of labial papillae. Most specimens agree with the preceding descrip- tion, but some have two rows of papillae lat- eral to the bare median part of the upper lip and two rows medially on the lower lip. In 108 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 some specimens, the first lower tooth row is narrowly interrupted. The extreme condition in number of rows of papillae is that illus- trated and described by Duellman ( 1963b ) . Mating Call: The call consists of a single, or sometimes double, note — "chock," repeated at intervals of eight seconds to about one minute. Analysis of recordings and notes taken in the field revealed that some indi- viduals emitted a series of calls in which the double notes were more numerous than the single notes, but no individual emitted more than three consecutive double notes, whereas some individuals emitted only single notes. The duration of the notes is 0.08 to 0.24 (mean, 0.16) of a second. The notes are characterized by a pulse rate of 180 to 200 (mean, 189) pulses per second. The notes are characterized by 11 to 35 (mean, 20.8) pulses; the last few pulses are intensified. The fundamental frequency falls between 165 to 200 (mean, 182) cycles per second, and the dominant frequency lies at 1488 to 2400 (mean, 1975) cycles per second (pi. 38, fig. 2). There is some noticeable geographic varia- tion in the calls; especially evident is a de- crease from north to south in the pulse rate and a corresponding lowering of the funda- mental and dominant frequencies (table 11). Natural History: Agalychnis callidryas inhabits forested regions where it breeds in temporary and permanent ponds during the rainy season. In the drier parts of the range, where the rainy season is short (for example, Campeche and southern Veracruz, Mexico, and northern El Peten, Guatemala), the breeding season is shorter than in areas char- acteristically having a long rainy season. Call- ing males were taken in October, November, and March in Bocas del Toro Province, Pan- ama. Numerous workers (Dunn, 1931b; Breder, 1946; Pyburn, 1963; and Duellman, 1963b) have presented data on the breeding habits of this species. The observations presented in these papers are incorporated here with my own unpublished observations. Daytime and dry season retreats appar- ently are in trees. Stuart (1958, p. 18) re- ported finding the frogs in palm fronds in the dry season at Tikal, El Peten, Guatemala, and I obtained one individual from a bromeliad at Laguna Monte Alegre, Alajuela Province, Costa Rica. At several different localities (Toocog, El Peten, Guatemala, and Laguna, Tacarcuna, and Rio Tuira, Darien Province, Panama) frogs were observed descending trees at dusk. At Toocog the frogs descended a large vine-covered tree standing in the wa- ter. At Laguna and Rio Tuira the frogs were in large trees on slopes near the breeding ponds. On several evenings at Laguna, the breeding area was under observation prior to dusk. Shortly after sunset Agalychnis calli- dryas was heard to call from heights in the trees. Some of the calls were the normal mat- ing calls, but most were a series of notes which might correspond to the rain-call of some frogs (pi. 30, fig. 3). In each observa- tion, within about five minutes most of the TABLE 11 Variations in the Mating Call of Agalychnis callidryas. ( The means are given in parentheses ) Locality N Oaxaca, Mexico — 6 El Peten, Guatemala .. 5 Buenos Aires, Costa Rica 3 Canal Zone, Panama 9 Darien, Panama 2 Duration of Notes ( seconds ) Pulse Rate ( seconds ) Fundamental Frequency (cps) Dominant Frequency (cps) 0.10-0.20 190-195 168-200 2016-2400 (0.16) (193) (183) (2185) 0.19-0.23 180-195 174-192 1990-2293 (0.22) (188) (184) (2097) 0.16-0.24 190-200 174-191 1910-2088 (0.19) (193) (182) (2000) 0.08-0.14 180-195 16.5-191 1488-1914 (0.11) (182) (176) (1734) 0.17-0.19 180 160-182 1920-2002 (0.18) (171) (1961) 1970 DUELLMAN: HYLID FROGS 109 frogs ceased calling. Then followed a period of time in which the frogs descended to the pond and began producing the mating call. The function of the rain call is not known, although Blair "1958" [1959] and Bogert (1960) suggested that these calls in some Hyla in southeastern United States and Mex- ico might have a territorial function. In the case of Agalychnis call id ry as the calls at dusk seem to be more of an "awakening" vocaliza- tion. On two occasions these calls have been heard at dawn, after the frogs had left the pond and ascended trees. After a few minutes of vocalizations from the trees the frogs be- came silent as the sky lightened. This vocali- zation at dawn adds support to the idea that these calls have a territorial function, but observations are too incomplete at this time to do more than raise questions concerning this phase of the frogs' behavior. Males call from trees and bushes above, or at the edge of, the water. Usually they sit perpendicular to the axis of the branch or vine on which they are perched. The perches usually are one to three meters above the water, but some males have been observed 8 to 10 meters above the water. At most breeding sites the males seem to be well spaced about the pond, but in some restricted sites they were found to be crowded. Even though some individuals were calling from adjacent positions on the same branch, no aggressive behavior was noted. Gravid females have been observed ap- proaching calling males, which usually see the female only after she has approached to within a few centimeters of the male. Once the male sees the female, he walks to her and clasps her. Extremes in this behavior have been noted. One female walked about one meter out on a limb and approached a male calling from a position perpendicular to the limb. The male continued to call as the female placed a hand on his back and did not take notice of her until after she had crawled over him and preceded a short distance be- yond him. On three occasions males were observed to clasp other males. In two in- stances the clasped male called (apparently the normal mating call), and the clasping male released his hold. In a third instance the clasped male jumped (with the clasping male on his back) into the water about two meters below; upon impact the clasping male released his hold. Amplexus is axillary. My observations sup- port those of Pyburn' (1963, p. 158) on the placid nature of the males once they are in amplexus. Usually the males adhere closely to the backs of the females and often close their eyes. A notable exception to this be- havior was a clasping pair observed in a pond 3 kilometers north of Donaji, Oaxaca, Mexico. A distinctly odd-sounding Agalychnis call was heard; it was traced to a male in amplexus. Females carry the males on their backs and climb or walk about in trees and bushes apparently in search of a suitable egg-deposi- tion site. Fouquette ("1966" [1967], p. 170) observed a clasping pair in the water in a ditch and suggested that amplectant pairs move first to water and then to vegetation above the water for oviposition. The eggs are deposited usually on leaves that are over the water; sometimes the eggs are suspended from vines or branches, and one clutch was adherent to a tree trunk. Pyburn ( 1962, p. 158) did not observe attempts by the frogs to curl the leaves around the eggs. I observed leaves curled about eggs as they were being deposited at Teapa, Tabasco, Mexico, and on the Cerro La Campana, Panama Province, Panama. In both cases the leaves were partly curled when I made my first observations, and I saw no activity on the part of the frog that resulted in curling the leaves. Several clutches of eggs completely encircled by leaves have been found. I suspect that this is a result of attachment of the eggs to particular kinds of leaves and not the result of the frogs curling the leaves as stated bv Goin (1960a, p. 438). Pyburn (1963, p. 159) reported 40 to 68 (mean, 51) eggs in nine clutches at Encinal, Veracruz, and Duellman (1963, p. 226) found 14 to 44 (mean, 29) eggs in 26 clutches at Toocog, Guatemala. Fifteen clutches at Cerro La Campana, Panama, contained 29 to 78 (mean, 43) eggs, and 11 clutches at the Rio Tuira at the Rio Mono, Panama, contained II to 39 (mean, 26) eggs. Three gravid females from Toocog contained 39, 78, and 91 ovulated eggs, and four females from Cerro La Campana contained 53, 79, 96, and 108 ovulated eggs. In addition to the 110 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 ovulated eggs two of the females from Too- cog and all of those from Cerro La Cam- pana contained about equal numbers of ovar- ian eggs that were about one-half of the size of the ovulated eggs. Roth ovarian and ovulated eggs were pale green. The disparity in the numbers of ovulated eggs and those making up the clutches suggests that each clutch represents only part of the egg comple- ment of a given female. Whether different clutches deposited by a single female repre- sent matings with one or more males is not known. Furthermore, the presence of large ovarian eggs in females containing ovulated eggs indicates a strong possibility that the females ovulate twice in one breeding season. The eggs are rather evenly distributed near the surface of the mass of clear jelly. In early stages of development the yolk is pale green, and the animal pole is brown. In later stages the yolk is yellow. Duellman (1963b, p. 226) briefly described eggs of Agahjchnis callidryas from Toocog, Guate- mala. He reported that in eggs in yolk plug stage the average diameter of the embryos was 2.3 mm. and that of the inner envelopes, 3.4 mm. Pyburn (1963) described and illus- trated in detail the embryonic development of this species at Encinal, Veracruz; the reader is referred to this paper for the de- scriptive embryology. Hatching is accomplished by vigorous wriggling by the tadpole, which thereby rup- tures the egg membranes and drops to the water below. Duellman (1963b, p. 227) ob- served one clutch of 19 eggs hatching within three minutes. Obstacles, such as branches or emergent vegetation, sometimes impede the fall to the water, and because of placement of some clutches, the tadpoles fall onto the ground. Pyburn (1963, p. 160) stated: "Newly hatched tadpoles of callidryas are capable of Hipping themselves about on a dry surface by vigorous contractions of the tail musculature, and could conceivably get to standing water if they fell within a few inches of the water's edge." The newly hatched tadpoles apparently sink to the bottom of the pond, and one or two minutes elapse from the time they drop into the water until they reappear at the sur- face. The tadpoles characteristically orient themselves head up near the surface of the water. Large tadpoles were observed to con- gregate in open sunny parts of the pond at Toocog, Guatemala. Metamorphosing young have been found throughout the latter part of the rainy season and into the dry season. Stuart (1958, p. 18) found young in February at Tikal, Guate- mala. Pyburn (1963, p. 168) raised the eggs of Agahjchnis callidryas and succeeded in rearing one individual to metamorphosis in 79 days after hatching. His metamorphosed young had a snout-vent length of 18.5 mm. Twenty young from 22 kilometers south of Managua, Nicaragua, have snout-vent lengths of 19.7 to 21.9 (mean, 20.6) mm., and four from Laguna, Darien Province, Panama, have snout-vent lengths of 19.2 to 19.7 (mean, 19.5) mm. Pyburn (1963, p. 168) noted that the young had a green dorsum, a yellow iris, and lacked vertical bars on the flanks. Speci- mens from Panama were reddish brown at night but changed to pale green by day. They had a yellowish gold iris and lacked bars on the flanks. Starrett (1960a, p. 30) raised re- cently metamorphosed young from Los Dia- mantes, Limon Province, Costa Rica. Regard- ing the development of the color pattern she stated: "The green adult coloration did not appear until resorbtion of the tail had begun. At about the time that the tail disappeared the white lateral stripe was noticeable, but the vertical stripes and purple color on the lower sides did not appear for several weeks. The vertical pupil of the froglet was noticed when the froglet crawled out of the water, but the red color did not become apparent for two weeks. Then it took several days for the eye to become completely red as the coloration spread inward over the iris from the periphery where it first became evident." In the series of young from 22 kilometers south of Managua, Nicaragua, some individ- uals have a longitudinal white stripe present along the length of the flank, whereas in others the stripe is present only posteriorly. None has vertical bars. Recently metamor- phosed young have only slight webbing be- tween the fingers; the toes are about one- third webbed. Remarks: Most workers in the present century, prior to Funkhouser ( 1957 ) , recog- 1970 DUELLMAN: HYLID FROGS 111 nized two taxa of Central American Agalych- nis with pale vertical or diagonal bars on blue flanks; A. helenae was characterized by the presence of a longitudinal white line on the flanks and blue thighs, whereas A. callidryas had orange thighs and lacked the longitudinal line. Funkhouser (1957) named the Mexican and Guatemalan populations A. callidryas tay- lori, which she diagnosed as differing from the nominate subspecies in size and certain proportions. Savage and Heyer ( 1967 ) partially ana- lyzed the variation in these three taxa and concluded that only one species was repre- sented. Furthermore, they argued that the variation was such as to preclude the recog- nition of subspecies. Savage and Heyer care- fully analyzed the variation in the color pat- tern on the flanks and the size of adults and briefly mentioned the color of the thighs; their conclusions were based principally on the pattern. When the variation in the color of the flanks and the number of bars on the flanks are also taken into consideration (table 9 ) , the correlation of variation in two or more characters takes on a different aspect than that presented by Savage and Heyer. They stated that on the basis of pattern the speci- mens from the Pacific lowlands of Costa Rica and western Panama are like those of the Mexican, Guatemalan, and Honduranean specimens. The significance of the similarity in pattern is diminished by the differences in the colors of the flanks and the numbers of vertical bars present in the two samples (table 9). No specimens have been examined that are intermediate between the northern popu- lations (orange thighs and no longitudinal white stripe on the flank ) and the Nicaraguan and Costa Rican populations ( blue thighs and a white stripe on the flank). A broad hiatus of about 300 kilometers separates the southeast- ernmost locality of the northern population from the Nicaraguan population. The absence of specimens from the intervening area prob- ably is due to lack of collecting and not to the absence of the frogs in that area. Many specimens from Bocas del Toro Province and some specimens from the Canal Zone and Cerro La Campana, Panama, have blue on the proximal surfaces of the thighs, which otherwise are orange. Furthermore, a pattern of T-shaped bars, some of which are connected dorsally, on the flanks occurs in these specimens. Therefore, in these char- acters the frogs are intermediate between the Nicaraguan-Costa Rican populations and those in eastern Panama. Frogs having char- acteristics of the Caribbean populations are found on the Pacific slopes only on Cerro La Campana, which has a herpetofauna com- posed of many species that predominantly range only on the Caribbean slopes. Other samples from the Pacific lowlands of Panama and Costa Rica are characterized by many vertical bars ( lacking a dorsal connection ) , brown flanks, and orange thighs. Several taxononric arrangements of the populations are possible. Savage and Heyer (1967) argued strongly against taxonomic recognition of any of the populations. Equally valid evidence supports the recognition of three taxa — a northern population from Hon- duras to Mexico, a central population in Nica- ragua and Costa Rica, which apparently in- tergrades with a third population occurring in Panama and on the Pacific lowlands of Costa Rica. Since the evidence for the taxo- nomic recognition of the populations is not much more impressive than Savage and Hey- er's evidence for regarding all of the popula- tions as one taxon, no formal taxonomic changes should be proposed until specimens are obtained from the Honduranean hiatus. Presumably specimens from that area will provide the necessary evidence to determine whether or not the northern population inter- grades with that in Nicaragua. Etymology: The specific name callidryas is derived from the Greek kallos, meaning beautiful, and the Greek Dryas, a tree nymph. Distribution: The range of Agalyclmis callidryas, as now recognized, includes the Atlantic slopes and lowlands from southern Veracruz and northern Oaxaca, Mexico, south- eastward to northern Honduras and thence, presumably continuous, southward on the Caribbean slopes and lowlands to the Canal Zone, Panama, east of which the species oc- curs on the Pacific lowlands ( fig. 37 ) . A dis- junct population occurs on the Pacific low- lands from the area between Esparta and San Ramon, Costa Rica, southeastward to extreme 112 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 western Chiriqui Province, Panama. Old rec- ords for die species in Yucatan, Mexico are based on specimens obtained at cenotes. It is doubtful if the species is widely distributed in the Yucatan Peninsula. I heard, but did not obtain, individuals at Felipe Carrillo Puerto, Quintana Roo. The species is characteristic of the lowlands throughout its range, but does ascend the slopes of mountains in many places. It has been taken at 740 meters on Cerro La Campana, Panama, 780 meters at Silencio, Costa Rica, 820 meters at Laguna, Panama, and at 960 meters at Finca Tepeyac, Nicaragua. See Appendix 1 for the locality records of the 969 specimens examined. Agalychnis moreletii (Dumeril) Hyla moreletii Dumeril, 1853, p. 169 [holotype, M.N. H.N. No. 767 (two syntypes) from "Verapaz," Guatemala; Arthur Morelet collector; type locality restricted to Coban, Alta Verapaz, Guatemala by Smith and Taylor ( 1950, p. 317)]. Brocchi, 1882, p. 31. Hyla holochlora Salvin, 1860, p. 460, pi. 32, fig. 5 [holotype, B.M.N. H. No. 1947.2.24.23 from Coban. Alta Verapaz, Guatemala; Osbert Salvin collector]. Agalychnis moreletii: Cope, 1865a, p. 110 [trans- fer of Hyla moreletii Dumeril to Agalychnis Cope, 1865a]. Boulenger, 1882a, p. 422 [synonymized Hyla holochlora Salvin, 1860, with Agalychnis moreletii (Dumeril, 1853)]. Gunther, 1901 (1885-1902), p. 289 [part, specimens from Guatemala]. Smith and Taylor, 1948, p. 71. Duellman, 1968b, p. 4. Phyllomedusa moreletii: Kellogg, 1932, p. 146 [transfer of Agalychnis moreletii (Dumeril) to Phyllo- medusa Wagler, 1830]. Funkhouser, 1957, p. 40. Stuart, 1963, p. 38. 78° 12° 0 100 KILOMETERS 18' 96° 90° 84° Fig. 37. Distribution of Agalychnis callidryas. 1970 DUELLMAN: HYLID FROGS 113 Diagnosis: This moderate-sized species, having the hands and feet about three-fourths webbed, is distinguished from other species of Agalychnis by having uniformly orange flanks and thighs and a dark red eye. Some Agalychnis callidryas have orange thighs, but that species has blue, purple, or brown flanks with vertical cream-colored bars; spurrelli has yellow flanks and thighs, but differs in having black-bordered white spots on the dorsum and fully webbed hands and feet. Structurally moreletii is close to annae, which has uni- formly blue flanks and thighs, an orange eye, slightly less webbing (figs. 28 and 30), and a smaller tympanum; the ratio of the diameter of the tympanum to that of the eye in annae is 0.431 to 0.627 (mean, 0.563), as compared with 0.603 to 0.714 (mean, 0.670) in moreletii. Description: Agalychnis moreletii is a moderately large, slender species; males attain a maximum snout-vent length of 65.7 mm. (mean, 25 specimens, 60.6 mm.), and females reach 82.9 mm. (mean, six specimens, 78.3 mm.). In a sample of 25 males from Finca Chicoyou, Alta Verapaz, Guatemala, the ratio of tibia length to snout-vent length is 0.332 to 0.390 (mean, 0.367); the ratio of foot length to snout- vent length is 0.332 to 0.390 (mean, 0.367); the ratio of head length to snout-vent length is 0.311 to 0.344 (mean, 0.328); the ratio of head width to snout-vent length is 0.295 to 0.330 (mean, 0.309), and the ratio of the diameter of the tympanum to that of the eye is 0.603 to 0.714 '(mean, 0.670). The frogs from Valentin, British Honduras, are slightly smaller, but the proportions are about the same. Eleven breeding males have snout- vent lengths of 51.1 to 59.0 (mean, 57.6) mm., and three females, 71.0 to 73.0 (mean, 72.4). The head is about as wide as the body, and the top of the head is slightly convex. In dorsal profile the snout is narrow and acuminate. In lateral profile, in males, the snout gently slopes from the eyes to the nos- trils and is further inclined to the tip of the snout; in females, the snout anterior to the nostrils is bluntly rounded. The nostrils are slightly protuberant and are about two-thirds the distance from the eyes to the tip of the snout. The canthus is rounded, but distinct; the loreal region is barely concave, and the lips are thin and slightly flared. A dermal fold extending from the posterior corner of the eye to a point just posterior to the angle of the jaw conceals the upper and posterior edges of the tympanum, which otherwise is distinct. The tympanum is posterior, and slightly ventral to the eye and separated from it by a distance equal to about one-third of the diameter of the tympanum. The upper arm is slender, whereas the forearm is robust. A narrow dermal fold ex- tends from the elbow along the ventrolateral edge of the forearm and fourth finger to the disc. The fingers are relatively short and have large discs; the diameter of the disc on the third toe is greater than the diameter of the tympanum but less than that of the eye. The subarticular tubercles are moderately small and round, except that in many specimens the distal subarticular tubercles on the third and fourth fingers are bifid. The pollex is slightly enlarged in breeding males and bears a non-spinous horny nuptial excrescence. The fingers are about three-fourths webbed (fig. 28A). The webbing includes the basal pha- langes to the base of the penultimate phalanx of the first and medial edges of the second and third fingers, to the middle of the pen- ultimate phalanx on the fourth and lateral edge of the third finger, and to the base of the disc on the lateral edge of the second finger. The hind limbs are slender; the ad- pressed heels broadly overlap, and the tibio- tarsal articulation extends to the eye. A der- mal fold extends along the median edge of the shank, across the heel, and along the ventrolateral edge of the tarsus to the disc on the fifth toe. In most specimens, a well- developed tarsal fold extends the full length of the tarsus, but in some individuals the fold is weak, especially distally. The inner meta- tarsal tubercle is large, flat, and elliptical. The toes are relatively short and slender, and the terminal discs are nearly as large as those on the hand. The subarticular tubercles are moderately large and round. The toes are about three-fourths webbed (fig. 30A). The web connects the first and second toes at the bases of the penultimate phalanges, extends from the base of the disc on the second toe to the base of the penultimate phalanx of the third toe, from the base of the disc of the third toe to the base of the penultimate pha- 114 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 lanx of the fourth and on to the base of the disc of the fifth toe. The anal sheath is long and folded later- ally. The anal opening is directed ventrally at the level of the ventral surfaces of the thighs. The skin of the dorsum, chin, and ventral surfaces of the limbs, except the thighs, is smooth, whereas the skin on the belly and ventral surfaces of the thighs is moderately granular. The tongue is only slightly longer than wide, shallowly notched anteriorly, deeply notched posteriorly, and free behind for about one-third of its length. The dentigerous processes of the prevomers are transverse ridges between the posterior margins of the ovoid choanae. Males have five to seven teeth on each process and a total of 10 to 13 (mean, 11.2) prevomerine teeth. Females have six to eight teeth on each process and a total of 12 to 16 (mean, 14.2) prevomerine teeth. The vocal slits are short; each is situated along a line from the postero- lateral edge of the tongue to the angle of the jaw. The vocal sac is single, median, subgular, and not noticeably distensible. The general coloration consists of a green dorsum, creamy yellow venter, and orange flash marks (pi. 43, fig. 1). The dorsal sur- faces of the head, body, and hind limbs, fore- arms, fourth fingers, and fifth toes are leaf green, varying in some individuals to dark green and to pale green in others. The flanks, anterior and posterior surfaces of the thighs, the inner surfaces of the shanks, tarsi, and forearms, the upper arms, first three fingers and first four toes are orange. A broad diffuse creamy yellow stripe on the flanks separates the green dorsum from the orange flanks. The throat and belly are creamy yellow. The stripes on the outer edges of the forearm and tarsi are white. The iris is a dull red or ma- roon. The palpebral membrane is reticulated with gold, and the nuptial excrescences in breeding males are dark grayish brown. Many individuals when active at night are dull green above; in these individuals the flash colors are dark orange. Recently meta- morphosed young were pale green with creamy white flanks and thighs when found at night. By day the dorsum changed to a pale orange-brown. In preservative, the dorsal surfaces of the body, forearms, hind legs, fourth fingers, and fifth toes became dull dark blue. The rest of the surfaces are creamy white. In most individuals green is present only distally on the dorsal surfaces of the thighs, but in some specimens the green extends to the midlength of the thigh or even to the groin. Specimens from British Honduras are distinctive in hav- ing scattered white flecks on the dorsum. Tadpoles: Ten hatchling tadpoles (stage 23) from Finca Chicoyou, Alta Verapaz, Gua- temala, have body lengths of 5.8 to 6.8 (mean, 6.4) mm. and total lengths of 12.7 to 13.4 (mean, 13.0) mm. Five tadpoles in stages 30 to 31 from the same locality have body lengths of 16.5 to 18.5 (mean, 17.7) mm. and total lengths of 32.5 to 40.0 (mean, 46.1) mm., and one tadpole with hind limbs (stage 40) has a body length of 22.0 mm. and a total length of 55.0 mm. Tadpoles are available in stages 28 to 36 with the mouth parts fully developed; these tadpoles have limb buds in the later stages (fig. 31E). In these tadpoles the body is noticeably deeper than broad; it is deepest posteriorly and widest at the level of the eyes. The snout in dorsal profile is truncate; in lat- eral profile it is acuminate, protruding, and dorsal to the midline. The nostrils are dorso- lateral, about one-third the distance from the snout to the eyes, and directed anterolaterally. The eyes are dorsolateral and are directed laterally. The diameter of the eye equals about one-fifth of the greatest depth of the body. The spiracle is ventral and sinistral to the midline; the spiracular opening is at a point just posterior to the eye. The mouth is on the anteroventral surface of the protruding snout and directed anteriorly. The cloacal tube is short and dextral to the caudal fin. The caudal musculature is moderately robust; its depth at midlength of the tail is equal to the depth of the dorsal fin. Distally the caudal musculature is slender; it does not extend to the tip of the tail. The dorsal fin is deepest at midlength of the tail and does not extend onto the body. The ventral fin is slightly deeper than the dorsal fin and has equal depth on the anterior three-fourths of the tail. The mouth has a shallow lateral fold. The median part of the upper lip is bare; the rest of the mouth is bordered by two rows of 1970 DUELLMAN: HYLID FROGS 115 papillae, except just lateral to the median bare part of the upper lip and the median part of the lower lip where but one row of papillae is present. Laterally scattered small papillae lie medially to the fringing rows. The upper beak is moderately deep and forms a broad arch; the lateral processes are slender, but expanded distally. The lower beak is moder- ately heavy. Both beaks have short, pointed serrations. There are two upper and three lower rows of teeth. The two upper rows are about equal in length and extend nearlv to the papillae; the second upper row is inter- rupted medially. The first lower row is nar- rowly interrupted medially and equal in length to the upper rows; the second and third lower rows are successively shorter than the first. The snout and top of the head and body are bluish gray with an olive-gray suffusion; in late stages the entire dorsal surfaces are olive-gray, but the sides of the body remain bluish gray. The ventral surfaces are silvery white. The caudal musculature is pale gray- ish tan. The caudal fins are transparent; scattered gray flecks are present on the fins and musculature. The iris is pale gold. Mating Call: The call of Agahjchnis moreletii consists of a single "wor-or-orp," repeated at intervals of one to several minutes. The duration of the notes is from 0.09 to 0.27 (mean, 0.13) of a second. The notes are characterized by a pulse rate of 55 to 61 (mean, 58) pulses per second; each note con- sists of three to six (mean, 4.1) pulses, the last of which is greatly emphasized in inten- sity. The notes are poorly modulated and have as many as seven emphasized harmonies scattered throughout the frequency spectrum from about 1000 to 7500 cycles per second. The fundamental frequency falls between 160 and 185 (mean, 172) cycles per second, and the dominant frequency lies at 1110 to 1260 (mean, 1171) cycles per second (pi. 38, fig. 3). Natural History: Agahjclinis moreletii inhabits humid, usually montane, forests where it usually breeds in woodland pools. A large breeding congregation was found at a deep pool in a cloud forest at Finca Chicoyou, Alta Verapaz, Guatemala, on July 18, 1960. The presence of tadpoles in advanced stages, as well as recently deposited eggs showed that the breeding activity there was spread over several weeks, if not months. Stuart ( 1948b ) noted the presence of breeding adults and tadpoles in various stages of development in a temporary pond at Finca Samac, Alta Verapaz, on June 30, 1938. Taylor and Smith ( 1945) reported the species breeding on May 8, 1940, at Finca Juarez, Chiapas, Mexico; the frogs were congregated around a pool in a stream, where eggs were deposited on boul- ders and on overhanging vegetation. Pyburn (1966) noted breeding Agahjchnis moreletii near Sontecomapan, Veracruz, Mexico, on August 11, 1962. Eggs were found attached to every con- ceivable vegetative structure above the pond. One clutch was adherent to a small rotting stem projecting upward from a partially sub- merged log; another was attached to a vine between two bushes. Most clutches were at- tached to leaves of bushes and low trees to heights of about two meters, but one clutch was seen on a leaf of a branch approximately 12 meters above the pond. Nineteen clutches contained 23 to 77 (mean, 49) eggs. One clutch of 94 eggs seems to have resulted from two depositions, and another of 103 eggs looked as though it was the result of two or three depositions. In each of these the clutches did not appear uniform and eggs in different parts of the gelatinous masses were in different stages of development. The jelly is clear. In early stages of development, the yolk is pale green; in later stages it is creamy tan. Small tadpoles, up to and including stage 31, were found amongst the leaf litter at the edge of the pool, whereas the larger tadpoles were observed in deep, open water in the middle of the pool. There they oriented them- selves close to the surface nearly vertically with the head up. When disturbed they dove to greater depths. One recently metamorphosed young has a snout-vent length of 19.8 mm.; only a ves- tigial web is present on the hand, and the toes are less than one-half webbed. Remarks: In the humid lower montane forests, or cloud forests, of southern Mexico and northern Central America, Agahjclinis moreletii is the ecological equivalent of A. 116 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 98° 94° 90° '•"'•-;---'' \ I ^ i ^ /■ y • /(7 1 - ' / ' [V \^ ?cf 20° r"'7 ^"Kx / • ) ;'_ y j / i / ** — 1 y If' /' i r i / i \ • / S ! / ; ! j 16° 16 0 50 100 200 • ^s ... * <<: KILOMETERS 1 ^— °! Q */\^ 98° 94° 90° Fig. 38. Distribution of Agalychnis morcletii. Open circles are literature records. annae, which occurs in the mountains of Costa Rica. Earlier workers, beginning with Bou- lenger (1882a) and including Funkhouser (1957), were not familiar with the animals in life and therefore were not aware of the striking differences in coloration between the northern Central American and Costa Rican populations that were pointed out by Duell- man (1963d). Etymology: The specific name morcletii is a patronym for Arthur Morelet, the collector of the type specimen. Distribution: The range of Agalychnis morcletii is discontinuous in humid montane forests between about 500 and 1500 meters on the Atlantic slopes of Sierra Madre Orien- tal in Veracruz and Oaxaca, in the Sierra de los Tuxtlas in Veracruz, Mexico, and in the mountains of Huehuetenango and Alta Vera- paz in Guatemala. The species occurs at similar elevations on the Pacific slopes of Oaxaca and Chiapas, Mexico, Guatemala, and El Salvador (fig. 38 ).4 The species also oc- curs at Valentin in British Honduras. Further collecting should reveal the presence of Aga- lychnis morcletii on the northern slopes of Chiapas and in the highlands of Honduras. In addition to the localities listed below, Mertens (1952b) recorded the species from the fol- lowing localities in El Salvador: Finca Los Angeles and Finca El Paraiso, Departamento La Libertad, and San Antonio, Departamento San Salvador. See Appendix 1 for the locality records of the 258 specimens examined. 1 Dr. Kraig Adler obtained Agahjclinis morelcti near San Andreas de la Cruz, Guerrero, in December, 1969. 1970 DUELLMAN: HYLID FROGS 117 Agalychnis annae (Duellman) Agalychnis moreletii: Boulenger, 1882a, p. 422 [part, specimens from Costa Rica]. Giinther, 1901 ( 1885-1902), p. 289 [part, specimens from Costa Rica]. Taylor, 1952c, p. 802. Funkhouser, 1957, p. 40 [part, specimens from Costa Rica]. Phyllomedusa annae Duellman, 1963d, p. 1 [holo- type, K.U. No. 64020 from Tapanti, Cartago Province, Costa Rica, 1200 meters; Ann S. Duellman collector], Agalychnis annae Duellman, 1968b, p. 4. Diagnosis: This moderately large species is distinguished from other members of the genus Agalychnis by having uniformly dark blue flanks and thighs and an orange eye. Other species having blue on the flanks either are much smaller or have vertical cream- colored bars on the flanks; thus, saltator is smaller and has less webbing, and callidryas has vertical cream-colored bars on the flanks. Agalychnis moreletii most closely approaches annae in morphological characters, but dif- fers in having orange flanks and thighs, a dark red eye, slightly more webbing on hands and feet (figs. 28 and 30), and a slightly larger tympanum; the ratio of the diameter of the tympanum to that of the eye in moreletii is 0.603 to 0.714 (mean, 0.670), as compared with 0.431 to 0.627 (mean, 0.563) in annae. Agalychnis spurrelli and litodryas lack the blue color on the flanks and thighs, and have dark red eyes and much larger, fully webbed hands and feet. Agalychnis calcarifer and craspedopus have yellow flanks and thighs boldly barred with black and prominent der- mal appendages on the heels. Description': Agalychnis annae is a mod- erately large, slender species; males attain a maximum snout-vent length of 73.9 mm. (mean, 35 specimens, 67.8 mm.), and females reach 84.2 mm. (mean, five specimens, 82.9 mm.). In a sample of 35 males from Tapanti, Cartago Province, Costa Rica, the ratio of tibia length to snout-vent length is 0.418 to 0.478 (mean, 0.447); the ratio of foot length to snout-vent length is 0.341 to 0.404 (mean, 0.370); the ratio of head length to snout- vent length is 0.290 to 0.328 (mean, 0.313); the ratio of head width to snout-vent length is 0.274 to 0.309 (mean, 0.294), the ratio of the diameter of the tympanum to that of the eye is 0.431 to 0.627 (mean, 0.563). The head is narrower than the body, and the top of the head is slightly convex. In dorsal profile the snout is narrow and slightly acuminate. In lateral profile, in males, the snout gently slopes from the eyes to the nostrils and is further inclined to the tip of the snout; in females, the snout is relatively blunt. The nostrils are slightly protuberant and are situated at about two-thirds of the distance from the eyes to the tip of the snout. The canthus is rounded and indistinct; the loreal region is slightly concave, and the lips are thin and not flared. A heavy dermal fold extending from the posterior corner of the orbit to a point just posterior to the angle of the jaw conceals the upper and posterior edges of the tympanum, which otherwise is prominent. The tympanum is situated pos- teroventrally to the eye and separated from the eye by a distance equal to about one-half of the diameter of the tympanum. The upper arm is slender, whereas the forearm is robust. A narrow dermal fold ex- tends from the elbow along the ventrolateral edge of the forearm onto the base of the fourth finger. The fingers are relatively short and have large discs; the diameter of the disc on the third finger is equal to that of the tympanum. The subarticular tubercles are small and round; the distal subarticular tu- bercles on the third and fourth fingers are the largest and are bifid in some specimens. The pollex is moderately enlarged in males; in breeding individuals it bears a large, non- spinous, horny nuptial excrescence. The fin- gers are about two-thirds webbed (fig. 2SB); the webbing includes the basal phalanges to the base of the penultimate phalanx of the first, second, fourth, and lateral edge of the third finger, but only to the middle of the antepenultimate phalanx on the medial side of the third finger. The hind limb is slender; the heels of the adpressed limbs broadly over- lap, and the tibiotarsal articulation extends to the posterior corner of the eye. Two small tubercles are present on the heel, and a thin dermal fold extends from the heel along the ventrolateral edge of the tarsus to the fifth toe. A weak tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is large, flat, and elliptical. The toes are rela- tively slender, and the terminal discs are slightly smaller than those on the hand. The 118 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 subarticular tubercles are moderately large and round. The toes are about three-fourths webbed (fig. 30B); the webbing extends to the base of the penultimate phalanges of the first, second, and medial edge of third toes, to the base of the disc on the lateral edge of the third toe, to the middle of the antepen- ultimate phalanx of the fourth toe, and to the middle of the penultimate phalanx of the fifth toe. The anal sheath is long, and the anal opening is directed ventrally at the level of the ventral surfaces of the thighs. The skin of the dorsum, chin, and ventral surfaces of the limbs, except the thighs, is smooth, whereas the skin on the belly and ventral surfaces of the thighs is moderately granular. The tongue is half again as long as wide, notched anteriorly and posteriorly, and barely free behind. The dentigerous processes of the prevomers are transverse ridges between the elliptical choanae. Males have five to seven teeth on each process and a total of 10 to 14 (mean, 12.0) prevomerine teeth. Females have eight to 12 teeth on each process and a total of 17 to 23 (mean, 20.2) prevomerine teeth. The vocal slits are small; each is situ- ated about one-half the distance from the posterolateral edge of the tongue to the angle of the jaw. The vocal sac is single, median, subgular, and not noticeably distensible. The general coloration consists of a green dorsum, creamy yellow venter, and blue flash marks (pi. 43, fig. 3). The dorsal surfaces of the head, body, thighs, shanks, tarsi, and fore- arms are bright leaf green; the anal region is pale leaf green. The flanks, anterior and pos- terior surfaces of the thighs, dorsal surfaces of the third fingers (usually except discs), dorsal surfaces of discs of fourth fingers, dor- sal surfaces of fourth toes and discs of fifth toes, and the web between the fourth and fifth toes are blue. The stripe along the tarsus from the heel to the tip of the fifth toe and the stripe along the ventrolateral edge of the forearm from the elbow to the fourth finger are bright creamy yellow. The proximal dorsal surfaces of the upper arms are pink or laven- der; distally the dorsal surfaces are blue. The dorsal surfaces of the fourth fingers are green; except as previously noted, the rest of the dorsal surfaces of the fingers, toes, discs, and webbing is deep orange. The ventral surfaces of the limbs, and the belly in some specimens, are pinkish orange; the throat, chest, and belly (in most specimens) are creamy yellow. Tin' lower lip is creamy white. The iris varies from bright orange to yellowish orange with a copper-colored periphery and reticulations. The palpebral membrane is reticulated with greenish gold. The nuptial excrescences in breeding males are brownish black. The only noticeable variation in individual coloration is a general darkening of color at night. This is especially evident in the green, which changes to a dark green, and in blue, which changes to dark blue, almost purple in some individuals. Recently metamorphosed young are green like the adults, except that the young lack the blue coloring on the flanks, thighs, and extremities. The dorsal color changes to reddish brown in preservative. In preservative, the dorsal surfaces of the body, forearms, hind legs, fourth fingers, and fifth toes change to dull purple. The flanks, anterior and posterior surfaces of the thighs, lateral surfaces of the tarsi, dorsal surfaces of the fourth toes, median surfaces of the fore- arms, and dorsal surfaces of the third fingers are brown. All of the ventral surfaces and the dorsal surfaces of the first and second fingers and first, second, and third toes are creamy yellow. Tadpoles: Ten hatehling tadpoles (stage 23) from Tapanti, Cartago Province, Costa Rica, have body lengths of 3.2 to 4.4 (mean, 3.9) mm. and total lengths of 9.8 to 12.9 (mean, 11.3) mm. Five tadpoles in stage 31 from the same locality have body lengths of 11.0 to 12.4 (mean, 11.5) mm. and total lengths of 32.0 to 35.5 (mean, 33.2) mm., and two tadpoles having hind limbs (stage 39) have body lengths of 17.5 and 19.0 mm. and total lengths of 45.7 and 48.0 mm. The change in the length of the tail relative to the length of the body is evident in the comparison of the average ratio of tail length to total length in the three samples listed above. In tadpoles in stage 23 the ratio is 0.498; in stage 31, 0.656; and in stage 39, 0.638. The tail increases in length at a more rapid rate than the body until the hind limbs are well developed; then with the onset of metamorphosis the tail begins to shrink. 1970 DUELLMAN: HYLID FROGS 119 Tadpoles in stages 27 to 36 have the mouth parts fully developed and have undergone no external changes except for the development of small hind limbs in the later stages (fig. 31D). In these tadpoles, the body is as wide as deep; it is widest at the level of the eyes. In lateral profile, the snout is rounded; in dorsal profile, it is truncate. The nostrils are dorsolateral, about one-third of the distance from the snout to the eyes, and directed an- terolaterally. The eyes are dorsolateral and directed laterally; the diameter of the eye equals about one-third of the depth of the body. The spiracle is ventral and sinistral to the midline; the spiracular opening is at a point slightly more than one-third the distance from the snout to the posterior end of the body. The mouth is anteroventral and di- rected anteriorly. The cloacal tube is short and dextral to the caudal fin. The lateral line organs are arranged in a curved line between the nostril and the eye and continue pos- teriorly just median to the eye on the dorso- lateral surface of the body and thence onto the side of the anterior one-half of the tail. A branch of the lateral line system extends ventrally just behind the eye, then curves anteriorly below the eye, and extends nearly to the snout. The caudal musculature is rather weak; its depth at midlength of the tail is about one-third of the depth of the tail. The musculature does not cjuite extend to the tip of the tail; distally the musculature is slender and curved dorsally. The dorsal fin is deepest at midlength of the tail and does not extend onto the body; the ventral fin is deepest anteriorly. The mouth has a shallow lateral fold. The median part of the upper lip is bare; the rest of the mouth is bordered by two rows of papillae, but laterally scattered small papillae lie medially to the fringing row. The upper beak is deep and forms a broad arch; the lateral processes are slightly expanded dis- tally. The lower beak is massive. Both beaks have short, moderately pointed serrations. There are two upper and three lower rows of teeth. The upper rows are about equal in length, and the second upper row is inter- rupted medially. The first and second lower rows are about as long as the upper rows; the first lower row is interrupted medially in many specimens, and the second lower row is broadly interrupted medially in some speci- mens. The third lower row is much shorter than the others (fig. 32D). The snout and top of the head and body are heavily pigmented, giving a grayish brown appearance. The sides of the body are bluish gray, and the venter is pale blue with a decided silvery cast. The caudal mus- culature is pale grayish brown. The caudal fins are transparent with brown flecks on the proximal edges of the anterior one-half of both the dorsal and ventral fins. During development the amount of pigmentation on the dorsal surface of the body and on the caudal musculature increases, whereas the amount of pigment in the caudal fins de- creases. The iris is yellow. Mating Call: The call of Agalychnis annae consists of a single note, "wor-or-orp," repeated at intervals of 40 seconds to two minutes or longer. The duration of the notes is from 0.16 to 0.44 (mean, 0.31) of a second. The notes are characterized by a pulse rate of 38 to 50 (mean, 42) pulses per second; each note consists of six to 17 (mean, 11.5) pulses, the last of which is emphasized in in- tensity. The notes are poorly modulated with as many as eight emphasized harmonics scat- tered throughout the frequency spectrum from about 1000 to 8800 cycles per second. The fundamental frequency falls between 140 and 185 (mean, 161) cycles per second, and the dominant frequency lies at 1044 to 1295 (mean, 1165) cycles per second (pi. 39, fig. 1). Natural History: Agahjchnis annae in- habits humid lowland and montane forests where it breeds in woodland pools. Duellman (1963d) reported breeding activity at Ta- panti, Cartago Province, Costa Rica, from April 19 through June 6, 1961. Calling males were found there on March 22, 1966, and the species has been heard calling throughout the month of August. Although breeding ac- tivity may be concentrated in the early part of the rainy season (April and May), males probably call throughout the rainy season, which usually lasts until December. Possibly some breeding takes place throughout the rainy reason. The eggs are deposited in irregularly 120 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 shaped masses of jelly on leaves, branches, or vines from 35 to 240 cm. above the water ( pi. 8, fig. 4 ) . Sixteen clutches contained from 47 to 162 (mean, 106) eggs. The jelly is clear, and the individual egg membranes are visible. In early stages of development the yolk is pale green; in later stages the yolk is creamy tan. Measurements of 10 eggs in stage 4 of development ( four cells ) show that the diam- eter of the embryo is 3.36 to 3.44 ( mean, 3.41 ) mm., the fertilization (vitelline) membrane is 3.51 to 3.65 (mean, 3.59) mm., and the outer envelope is 3.93 to 4.26 (mean, 4.12) mm. The eggs apparently hatch in about six days after deposition. One clutch of eggs in stage 4 of development found at La Palma, San Jose Province, Costa Rica on May 8 hatched on May 13. Hatching is accomplished by vigorous wriggling of the tadpole through the egg capsule. Some tadpoles adhere to the surface of the egg mass; by vigorous tail- flipping they free themselves and drop into the water. Other tadpoles were observed to break through the membranes and to slide down the egg mass and drop into the water. Hatchling tadpoles sink to the bottom of the pond and remain motionless for several minutes before making faint swimming move- ments and sinking to the bottom again. At Tapanti, Cartago Province, Costa Rica, tad- poles in various stages of development to stage 36 were observed in a spring-fed pool partly filled with aquatic vegetation. Small tadpoles (up to stage 31) most frequently were found in vegetation-choked parts of the pond, whereas larger tadpoles were most often observed in deeper, open water. The large tadpoles orient themselves with their heads up and bodies at about a 45 degree angle to the surface of the water. The tip of the tail is curved slightly upwards and is fluttering con- tinuously. The large tadpoles are extremely wary; upon the slightest disturbance they swim downward or into dense vegetation. Tadpoles raised from eggs in the labora- tory metamorphosed in 247 days. Probably development is more rapid under natural con- ditions. This suggestion is supported by Py- burn's ( 1963 ) report of metamorphosing Aga- lychnis callidryas in 79 days after hatching. Four metamorphosing young of A. annae have snout- vent lengths of 20.7 to 22.8 (mean, 21.7) mm. In recently metamorphosed young, the head is proportionately larger than in the adults; the average ratio of head length to snout-vent length for the four young is 0.381, and the average ratio of head width to snout- vent length is 0.392. ( Compare with propor- tions of adults given in preceding descrip- tion. ) The juveniles also differ from adults by having only about one-half as much webbing on the hands and feet. Remarks.- This species was recorded from Costa Rica as early as 1882 by Boulenger, who together with succeeding workers through Taylor ( 1952c ) and Funkhouser ( 1957 ) con- sidered the Costa Rican frogs to be conspecific with Agalychnis moreletii in Mexico and Gua- temala. As pointed out by Duellman ( 1963d), knowledge of the Costa Rican and Guate- malan animals in life provided evidence that the two populations were not conspecific. Etymology: The specific name annae is a patronym for Ann S. Duellman. Distribution: Agalychnis annae occurs from low to moderate elevations (up to 1600 meters) on the Caribbean slopes of the Cor- dillera del Guanacaste, Cordillera Central, and Cordillera de Talamanca in Costa Rica ( fig. 39 ) . It probably occurs on the Caribbean slopes of western Panama. One specimen (M.C.Z. No. 8031) purportedly from Esparta on the subhumid Pacific lowlands of Costa Rica, probably bears erroneous locality data. See Appendix 1 for the locality records of the 239 specimens examined. Agalychnis calcarifer Boulenger Agalychnis calcarifer Boulenger, 1902a, p. 52 [holo- type, B.M.N.H. No. 1947.2.24.22 from "Rio Durango, northwestern Ecuador, 350 feet" ( =Esmeraldas Prov- ince), Rosenberg collector]. Duellman, 1968b, p. 4. Phyllomedusa (Agalychnis) calcarifer: B. Lutz, 1950b, p. 619, 620 [transfer of Agalychnis calcarifer Boulenger, 1902a to Phyllomedusa Wagler, 1830, at subgeneric status]. Phyllomedusa calcarifer: Funkhouser, 1957, p. 24 [transfer of Agalychnis calcarifer Boulenger, 1902a, to Pliyllomedusa Wagler, 1830]. Diagnosis: This moderate-sized Agalych- nis is readily distinguished from all other members of the genus (except craspedopus) by having a large dermal flap on the heel, orange-yellow flanks and thighs with bold, black vertical bars, yellow eye, and an un- 1970 DUELLMAN: HYLID FROGS 121 11° 86° 85° 84° 83° 11° - 3~\j — i -^s' 1 V i \ C • • • \ ^P^^ • 10° s • •• • 1 \- i \ 10° 9° 0 25 50 100 7 i 1 j . s ( \ ~\ • \ ' \ / J /' ^S /*~~r~*' . i v 9° KILOMETERS i i 86° 85° 84° 83° Fig. 39. Distribution of Agahjchnis annac. marked palpebrum. In other species having orange or yellow flanks (moreletii and spur- relli, respectively), vertical black bars are absent. The only other known species of Agahjchnis having vertical dark markings on the flanks and thighs is craspedopus, which differs from calcarifer by having large dermal flaps on the foot, dermal folds on the outer edges of the forearm and the fifth toe, and a truncate, instead of sloping, snout. Description: Agahjchnis calcarifer is a moderate-sized species; males attain a maxi- mum snout-vent length of 64.0 mm. (mean, five specimens, 52.0 mm.), and females reach 78.5 mm. (mean, four specimens, 65.0 mm.). Two breeding males from Laguna, Darien Province, Panama, have the following pro- portions: ratio of tibia length to snout-vent length, 0.515 and 0.520; ratio of foot length to snout-vent length, 0.373 and 0.377; ratio of head length to snout-vent length, 0.323 in both; ratio of head width to snout-vent length, 0.333 and 0.335, and the ratio of the diameter of the tympanum to that of the eye, 0.760 and 0.775. One female from the same locality has a snout- vent length of 61.6 mm. and differs noticeably in proportions only by having a slightly larger tympanum (tympanum/eye is 0.816). The largest female (U.S.C. No. 496) is from Finca La Selva, Heredia Province, Costa Rica; it has a snout-vent length of 78.5 mm. and differs from the Panamanian speci- mens in having a relatively long foot (the ratio of foot length to snout-vent length is 0.411) and much larger tympanum (tympan- um/eye ratio is 0.965). The head is wider than the body, and the top of the head is barely convex. In dorsal 122 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 profile, the snout is rounded and terminally truncate. In lateral profile the snout slopes from the eyes to the nostrils and is sharply- inclined to the tip of the snout in both sexes. The nostrils are slightly protuberant and are about three-quarters of the distance from the eyes to the tip of the snout. The canthus is heavy, rounded, and barely distinct; the loreal region is concave, and the lips are thin and not flared. A dermal fold extends from the posterior corner of the orbit along the upper and posterior edges of the tympanum to the angle of the jaw. The tympanum is distinct, posteroventral to the eye, and separated from the eye by a distance equal to about one-third of the diameter of the tympanum. The upper arm is slender, whereas the forearm is moderately robust. A broad dermal fold extends from the elbow along the ven- trolateral edge of the forearm to the disc on the fourth finger. The fingers are relatively short and have large discs; the diameter of the disc on the third finger is equal to, or slightly larger than, that of the tympanum. The subarticular tubercles are moderately large and round. One large female (U.S.C. No. 496) has bifid tubercles on the second, third, and fourth fingers; the other specimens have simple subarticular tubercles. The pol- lex is moderately enlarged and in breeding males it bears a large nuptial excrescence composed of many small horny spines. The fingers are about three-fourths webbed (fig. 27C ) . The web extends from the middle of the penultimate phalanx of the first finger to the base of the penultimate phalanx of the second finger, and from the base of the disc of the second finger to the base of the pen- ultimate phalanx of the third. The web con- tinues from the middle of the lateral edge of the penultimate phalanx of the third finger to the base of the disc on the fourth finger. The hind limb is slender; when the limbs are adpressed the heels overlap by about one- third the length of the thigh. The tibiotarsal articulation extends to a point between the eye and the tip of the snout in all specimens except the large female from Finca La Selva, Heredia Province, Costa Rica (U.S.C. No. 496), in which the heel extends anteriorly be- yond the snout. A large, triangular dermal flap is present on the heel. From the edge of the flap a narrow dermal fold extends along the outer edge of the tarsus to the disc on the fifth toe. Another less conspicuous dermal ridge extends the length of the dorsal edge of the tarsus onto the base of the fifth toe. The tarsal fold is weak and present only on the distal one-third of the tarsus. The inner metatarsal tubercle is rounded in profile and a long ellipse in shape. The toes are not especially slender; nor are they robust. The discs are about three-fourths the size of those on the hands. The subarticular tubercles are rather small and round. The toes are about three-fourths webbed (fig. 29C). The web- bing extends to the base of the discs on the first, fifth, and lateral edges of the second and third toes, to the middle of the penultimate phalanx on the medial edge of the second toe, and to the base of the penultimate phalanges on the fourth and medial edge of the third toe. The anal sheath is long and heavily folded laterally. The anal opening is directed pos- teroventrally at the median level of the thighs. The skin of the dorsum, chin, and ventral sur- faces of the limbs, except the thighs, is smooth, whereas the skin on the belly and on the proximal posteroventral surfaces of the thighs is granular. The skin on the chest is smooth in all specimens, except the largest female (U.S.C. No. 496), which has tubercles on the chest. The tongue is half again as long as wide, notched anteriorly and posteriorly, and barely free behind. The dentigerous proc- esses of the prevomers are transverse ridges between the choanae. Males have four or five teeth on each process and a total of nine or 10 (mean, 9.5) prevomerine teeth. One female has a total of 11 prevomerine teeth. The vocal slits are small apertures, one lying on each side of the posterior part of the at- tachment of the tongue. The vocal sac is single, median, subgular, and apparently not noticeably distensible. The general coloration consists of a dark green dorsum with flanks and thighs orange marked with black bars (pi. 42, fig. 3). The dorsal surfaces of the body, forearms, shanks, tarsi, fourth fingers, and fifth toes are dark green. The flanks, narrow dorsal surfaces of upper arms and thighs, and throat are yellow. The belly, ventral surfaces of the limbs, hands, 1970 DUELLMAN: HYLID FROGS 123 feet, anterior and posterior surfaces of the thighs, inner surfaces of the shanks, tarsi, and forearms, and all but dorsal surfaces of upper arms are deep orange. The vertical bars on the flanks and transverse bars on the dorsal surfaces of the thighs and the inner surfaces of the forearms, shanks, and tarsi are black. The stripes on the outer edge of the forearm and fourth finger, on the inner edge of the shank and outer edge of the tarsus and fifth toe are yellow. A yellow stripe is present on the sides and across the posterior edge of the anal sheath. The edge of the lower lip is dark green. The iris is pale grayish lavender medially and dull yellow peripherally. The palpebral membrane is clear. The nuptial excrescences in breeding males are dark brown. In preservative the dorsal surfaces of the body, forearms, shanks, and tarsi fade to dark blue. The black bars on the flanks and limbs remain black or change to dark brown. The orange and yellow fades to a pale creamy white. In the small sample available for study, some variation in color pattern is evident. The number of black bars on the flanks varies from three to six and on the thighs from three to five. A juvenile (A.N.S.P. No. 23219) from Barro Colorado Island, Canal Zone, has a snout-vent length of 27.5 mm. and lacks black marks on the flanks and thighs. In the five adults examined from Panama a narrow streak of green is present distally on the dorsal sur- face of the thighs. In these specimens, the green streak extends no farther than the mid- length of the thigh, but in one specimen from Costa Rica and one described from Colombia by Boulenger (1913) the streak extends the length of the thigh. Boulenger (1913, p. 1023) described the colors in life of the specimen from Pena Lisa, Condoto, Choco, Colombia, (based on field notes taken by Dr. H. Spur- rell) as follows: ". . . brilliant sage-green above, flanks and upper surface of thighs ( with the exception of a narrow green streak ) rich orange-yellow with black bars; hands and feet and lower parts orange-yellow; iris grey, bordered with orange-yellow; lower eyelid transparent, edged with "turquoise-blue." Tadpoles: The tadpoles of Agahjchnis cal- carifer are unknown. Eggs, presumably of this species, were found on a dead leaf over a pool of water in a log. Thus, it may be assumed that the tadpoles of this species, like those that are known in the genus, develop in quiet water. Mating Call: No recordings of the call are in existence; to my knowledge no biologist has heard the species. Natural History: Little is known about this frog, which is represented in museum collections by only nine specimens. Most of the individuals were found sitting on vege- tation in forests at night. At Laguna, Darien Province, Panama, on July 19, 1963, two males in breeding condition and one spent female were found by day. The frogs were hidden beneath parts of a log overhanging a pool of water that had collected in the log. A clutch of eggs was adhering to a dead leaf hanging over the pool. The 16 eggs were encased in clear jelly; the outer envelopes were not evi- dent. The eggs were in the yolk-plug stage. The average diameter of the eggs is 3.5 mm. and of the vitelline membrane, 4.0 mm. Remarks: The presence of the triangular dermal flap on the heel, extensive webbing, and black bars on the flanks and thighs sets Agahjchnis calcarifer apart from all other Central American species in the genus. How- ever, calcarifer seems to be closely related to Agahjchnis craspedopus ( Funkhouser ) . The latter is known from only two specimens from Chicherote, Napo Province in eastern Ecua- dor. Agahjchnis craspedopus resembles cal- carifer in general structure and color pattern, but differs by having a truncate snout, less webbing, and extensive dermal folds on the outer edge of the tarsus and fifth toe. These comparisons were made with the holotype of craspedopus (S.U. No. 10310). Etymology: The specific name calcarifer alludes to the triangular dermal flap on the heel and is derived from the Latin calcar meaning a spur and few meaning to carry. Distribution: Agahjchnis calcarifer is known from three localities in Central Amer- ica (fig. 40) and from two in South America [Rio Durango, Esmeraldas, Ecuador (Bou- lenger, 1902a) and Pena Lisa, Condoto, Choco, Colombia (Boulenger, 1913)]. All lo- calities are in the humid tropical lowlands ( highest elevation, 820 meters ) on the Carib- 124 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 40. Distribution of Agalychnis calcarifcr. bean side of Costa Rica and central Panama and on the Pacific side of eastern Panama, Colombia, and Ecuador. See Appendix 1 for the locality records of the nine specimens examined. Agalychnis spurrelli Boulenger Agalychnis spurrelli Boulenger, 1913, p. 1024, fig. 177, pi. 103 [holotype, B.M.N.H. Nos. 1947.2.24.24 and 25 ( two syntypes ) from Peria Lisa, Condoto, Choco Province, Colombia; H. Spurrell collector]. Duellman, 1968b, p. 4. Phyllomedusa spurrelli: Funkhouser, 1957, p. 39 [transfer of Agalychnis spurrelli Boulenger, 1913 to Phyllomedusa Wag)er, 1830], Diagnosis: This medium to large species having fully webbed hands and feet can be distinguished from all other Agalychnis by the presence of bright yellow flanks and thighs, dark red eye, and dorsum usually marked with black-bordered white spots. Although litodryas is nearly identical with spurrelli in structural features, the former can be sepa- rated in that it lacks pigment on the flanks and thighs and has no white spots on the dorsum. White pustular spots occur on the dorsal surfaces of many species of Agalych- nis, but only in spurrelli are these spots always narrowly outlined in black. Description: Individuals in some popula- tions of Agalychnis spurrelli attain a large size. The largest male examined is from Tacarcuna, Darien Province, Panama, and has a snout-vent length of 75.6 mm., whereas the largest recorded female is from Pefia Lisa, Choco, Colombia, and has a snout-vent length of 92.8 mm. (fide Cochran and Goin, 1970). In a sample of seven males from Barro Colo- rado Island, Canal Zone, Panama, the ratio of tibia length to snout-vent length is 0.473 to 0.514 (mean, 0.499); the ratio of foot length to snout-vent length is 0.368 to 0.411 (mean, 0.382); the ratio of head length to snout-vent length is 0.296 to 0.330 (mean, 0.311); the ratio of head width to snout-vent length is 0.310 to 0.328 (mean, 0.315), and the ratio of the diameter of the tympanum to that of the eye is 0.535 to 0.622 (mean, 0.569). The specimens from southeastern Costa Rica are much smaller than those from central and eastern Panama (table 12) and have rela- tively smaller tympani. Cochran and Goin (1970) gave the range in snout-vent length of eight males from Rio Manso, Cordoba, Colombia, as 47.2 to 52.2 mm. and of two fe- males as 62.4 and 66.3 mm. These measure- ments are similar to those obtained from 14 males and four females from southeastern Costa Rica, which have snout-vent lengths 1970 DUELLMAN: HYLID FROGS 125 respectively of 48.2 to 56.4 (mean, 51.9) mm. and 60.2 to 71.8 (mean, 65.6) mm., whereas the snout-vent lengths of 15 males and three females from Panama are much greater. The snout-vent length in males is 67.6 to 75.6 (mean, 72.1) mm. and in females, 81.6 to 86.7 (mean, 84.3) mm. Thus, on the basis of the small samples available the largest individuals apparently occur in the middle of the range, whereas individuals from the known periph- eral areas are smaller, although the largest known specimen, a female, is from the south- ern end of the range in Colombia. The head is wider than the body, except in gravid females, and the top of the head is flat. In dorsal profile, in both sexes the snout moderately slopes from the eyes to the nostrils and is further inclined to the tip of the snout. The nostrils are slightly protuberant and are about two-thirds of the distance from the eyes to the tip of the snout. The canthus is rounded, but distinct; the loreal region is slightly concave, and the lips are thin and moderately flared. A heavy dermal fold ex- tending from the posterior corner of the orbit to a point just posterior to the angle of the jaw conceals the upper and posterior edges of the tympanum, which otherwise is promi- nent. The dermal fold continues posteriorly as a flap above the insertion of the arm to the axilla. The tympanum is situated posterior, and slightly ventral, to the eye and is sepa- rated from the eye by a distance slightly less than one-half the diameter of the tympanum. The upper arm is slender, and the forearm is robust. A conspicuous dermal fold extends across the elbow and along the ventrolateral edge of the forearm to the disc on the fourth finger. The fingers are relatively short and have large discs; the diameter of the disc on the third finger is about equal to the diameter of the eye in Panamanian specimens, but only equal to about two-thirds the diameter of the eye in Costa Rican specimens. The subarticu- lar tubercles are round and moderate in size; in some large males and most females the distal subarticular tubercles on the third and fourth fingers are flattened and bifid. In one female (K.U. No. 77515) all, except the proximal tubercle on the fourth finger, are bifid. The pollex is greatly enlarged and bears a large, horny nuptial excrescence made up of minute spines. The fingers are about three-fourths webbed (fig. 28C). The web connects the first two toes at the bases of the penultimate phalanges, continues from the base of the disc of the second finger to the base of the penultimate phalanx of the third finger, and connects the third and fourth fingers at the bases of the discs. The hind limbs are slender. In Panamanian specimens, the heels of the adpressed limbs overlap by a distance equal to about one-third the length of the shank, and the tibiotarsal articulation extends to the anterior corner of the eye, whereas in Costa Rican specimens the heels barely overlap, and the tibiotarsal articula- tion extends to a point about midway between the eye and the tip of the snout. The skin on the shank tends to form a thin longitudinal fold on the ventrolateral and ventromedian surfaces. A thin dermal fold extends across the heel and along the outer edge of the tar- sus to the base of the disc on the fifth toe. A relatively strong tarsal fold extends the full length of the tarsus. The inner metatarsal TABLE 12 Comparison of Four Samples, with Means in Parentheses, of Adult Males of Agalyclmis spurrelli. Locality Snout-vent N Length ( mm. ) Tibia Length/ S-V L Foot Length/ S-V L Tympanum/ S-V L San Isidro el General, Costa Rica 10 Rincon de Osa, Costa Rica 4 Barro Colorado Island, Panama.. 7 Tacarcuna, Panama 8 49.9-56.4 0.457-0.493 0.365-0.413 0.508-0.647 (53.0) (0.476) (0.394) (0.558) 48.2-49.9 0.502-0.528 0.381-0.420 0.545-0.574 (49.0) (0.514) (0.399) (0.557) 70.6-74.6 0.473-0.514 0.368-0.411 0.535-0.622 (72.9) (0.499) (0.382) (0.569) 67.6-75.6 0.495-0.520 0.386-0.413 0.462-0.676 (71.1) (0.508) (0.401) (0.585) 126 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 tubercle is low, flat, and elliptical. The toes are long and slender, and the discs are slightly smaller than those on the fingers. The sub- articular tubercles are large and subcorneal. Supernumerary tubercles are present on the proximal segments of all of the toes. In Panamanian specimens, the toes are fully webbed (fig. 30C). Some males from Costa Rica have the web extending only to the bases of the penultimate phalanges on the fourth toe and the median edges of the second and third toes. The anal sheath is long, and the anal open- ing is directed ventrally at the level of the ventral surfaces of the thighs. The skin of the dorsum, chin, and ventral surfaces of the limbs, except the proximal surfaces of the thighs is smooth, whereas that on the belly and proximal surfaces of the thighs is granular. The granules form a distinct row on the pos- teroventral surfaces of the thighs. The tongue is about twice as long as wide, notched an- teriorly and posteriorly, and free behind for about one-third of its length. The dentigerous processes of the prevomers are transverse ridges between the narrowly elliptical cho- anae. Males have seven to nine teeth on each process and 14 to 17 (mean, 15.3) prevomer- ine teeth. Females have eight or nine teeth on each process and a total of 16 to 18 (mean, 17.0) prevomerine teeth. The vocal slits are short and are situated along the posterome- dian edges of the rami. The vocal sac is single, median, subgular, and not noticeably distensible. The general coloration consists of a green dorsum, usually with black-bordered white spots, and yellow flanks, thighs, and venter (pi. 43, fig. 6). Specimens from Barro Colo- rado Island, Canal Zone, Panama (K.U. Nos. 77499-77506), are pale leaf green on the dor- sal surfaces of the head, body, limbs, fourth fingers, and fourth and fifth toes. The chin and throat are yellow; all other ventral sur- faces, flanks, anterior and posterior surfaces of the thighs, leading edges of tarsi, first four toes, upper arms, inner edges of forearms, first three fingers, and all webbing and discs are orange. In some individuals, a narrow dark olive-green line separates the orange flanks from the green dorsum. All individuals have black-bordered spots on the dorsum. The stripes extending from the elbow along the outer edge of the forearm to the disc of the fourth finger, along the edge of the tarsus from the heel to the disc of the fifth toe, and across the anal flap are yellowish cream. The iris is deep crimson, and the palpebral mem- brane is reticulated with greenish gold. The nuptial excrescences in breeding males are dark brown. Specimens from Tacarcuna, Darien Prov- ince, Panama (K.U. Nos. 77507-77515), are like those from Barro Colorado Island, except that the throat and chest are creamy white instead of yellow. Notes on the coloration in life of 11 specimens from 16 kilometers south- west of San Isidro el General, San Jose Prov- ince, Costa Rica (U.S.C. No. 7220) provided by Dr. Jay M. Savage indicate that these specimens are colored like those from Barro Colorado Island, except that the throat and chest are cream, and the belly is pale orange. Savage's notes on a male (U.S.C. No. 7235) from the Peninsula de Osa, Puntarenas Prov- ince, Costa Rica, indicate that in this speci- men the dorsal white spots are narrowly out- lined by dark green. All Panamanian speci- mens and, according to Cochran and Goin ( 1970 ) , all Colombian specimens have con- spicuous white spots, narrowly outlined by black, on the dorsum, but four of the IS adult specimens from southeastern Costa Rica lack white spots. In preservative the dorsal ground color is blue to purple, and the ventral surfaces, flanks, upper arms, anterior and posterior surfaces of thighs, and hands and feet are creamy white. The dorsal spots are white with black borders. Metamorphosing young are green above and creamy white below. Tadpoles: Ten tadpoles in stages 34 to 37 from Rincon de Osa, Puntarenas Province, Costa Rica, have body lengths of 14.5 to 17.0 (mean, 15.8) mm. and total lengths of 40.0 to 43.0 (mean, 41.5) mm. The ratio of tail length to total length is 0.575 to 0.654 (mean, 0.619). The largest tadpole in stage 41 has a body length of 19.5 mm., a total length of 52.3 mm.; the ratio of tail length to total length is 0.589. Tadpoles in stage 36 have fully developed mouth parts and have undergone no external 1970 DUELLMAN: HYLID FROGS 127 changes except for the development of small hind limbs (fig. 31C). In these tadpoles the body is as wide as deep; it is nearly of uni- form width posterior to the eyes. The top of the head is flat. In lateral profile the snout is rounded; in dorsal profile it is truncate. The nostrils are dorsolateral, and directed laterally; the diameter of the eye equals about one-third of the depth of the body. The spiracle is a flap-like tube ventral and sinistral to the midline; the spiracular opening is at a point about two-thirds of the distance from the snout to the posterior end of the body. The mouth is anteroventral and directed an- teriorly. The cloacal tube is short and dextral to the caudal fin. The caudal musculature is rather weak; its depth at midlength of the tail is about one-third of the depth of the tail. The musculature extends nearly to the tip of the tail; distally the musculature is slender and curved dorsally. The dorsal fin is shallow anteriorly and does not extend onto the body; the ventral fin is deepest at about one-third of its length. The mouth has a shallow lateral fold. The median two-thirds of the upper lip is bare; the rest of the mouth is bordered by two or three rows of papillae, and laterally ad- ditional papillae are present. The upper beak is moderately shallow and forms a broad arch; the lateral processes are barely expanded dis- tally. The lower beak is heavy. Small blunt serrations are present on the upper beak and small pointed serrations on the lower beak. There are two upper and three lower rows of teeth. The upper rows are about equal in length, and the second upper row is inter- rupted medially. The lower rows are much shorter than the upper rows; the lower rows are progressively shorter, so that the third lower row is the shortest (fig. 32C). The snout and top of the head are olive- brown; the sides of the body are dark bluish gray, and the venter is pale bluish gray. The caudal musculature is grayish tan. Dark brown flecks are present on the sides of the body and on the proximal edges of the an- terior one-half of the fins; dark brown reticu- lations are present on the anterior one-half of the caudal musculature. During develop- ment the amount of dark pigment increases, so that in tadpoles in stage 41, the entire tail is marked with bold reticulations. Mating Call: The call of Agalychnis spurrelli consists of a single, low-pitched groan repeated at intervals of 10 to 17 sec- onds. The duration of the notes is from 0.34 to 0.40 (mean, 0.37) of a second. The notes are characterized by a pulse rate of 60 to 90 (mean, 75) pulses per second. Each note con- sists of 19 to 24 (mean, 23.5) pulses; the last pulse is not intensified. The fundamental fre- quency varies from 87 to 100 (mean, 94) cycles per second, and the dominant fre- quency varies from 435 to 700 (mean, 568) cycles per second (pi. 39, fig. 2). Natural History: Agalychnis spurrelli inhabits humid tropical lowland forests, where it breeds in woodland pools and water-filled cavities in logs. Calling males were found in trees above and near a water-filled cavity in a log on Barro Colorado Island, Canal Zone, on June 3, 1963, and males were calling from a large tree in a temporary pond at Tacar- cuna, Darien Province, Panama, on July 16, 1963. Boulenger ( 1913, p. 1024) reported that a clasping pair was obtained on April 2 at Pena Lisa, Condoto, Choeo, Colombia, and that 66 eggs were preserved with the speci- mens. Dr. John D. Lynch obtained the tadpoles and metamorphosing young of this species at a locality 4.5 kilometers west of Rincon de Osa, Puntarenas Province, Costa Rica, on August 7 and 10, 1966. Tadpoles were found in a water-filled cavity in a log at the edge of the forest and in a shallow, weedy pond. The tadpoles orient themselves with their heads up and bodies at about a 45 degree angle to the surface of the water, but dive for cover at the slightest disturbance. By day when the pond was in direct sunlight the tadpoles were hidden among leaves on the bottom of the pond. Three metamorphosing young have snout- vent lengths of 18.2 to 20.0 (mean, 19.1) mm. The head is proportionately larger than in the adults, and there is less webbing on the hands and feet. One individual has distinct white spots on the dorsum. Remarks: The number of known speci- mens is insufficient to interpret the great dis- parity in size between the populations in 128 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 10' 50 100 KILOMETERS Fig. 41. Distribution of Agalychnis spurrelli and Agalychnis litodryas. southeastern Costa Rica and those in central and eastern Panama. Furthermore, life his- tory data are lacking for the Panamanian pop- ulations, and recordings of the mating calls are not available for the Costa Rican popula- tions. Etymology: The specific name spurrelli is a patronym for Dr. H. G. F. Spurrell, who collected the type series in Colombia. Distribution: Agalychnis spurrelli occurs at low elevations ( up to 885 meters ) in humid tropical forests in the Golfo Dulce region of southeastern Costa Rica, the Caribbean slopes of western Panama, and the Pacific lowlands of eastern Panama southward along the Pa- cific coast of Colombia (fig. 41). See Appendix 1 for the locality records of the 47 specimens examined. Agalychnis litodryas (Duellman and Trueb) Plujllomedusa litodryas Duellman and Trueb, 1967, p. 125 [holotype, K.U. No. 96149 from approximately 1 kilometer west-southwest of the junction of the Rio Mono and the Rio Tuira, Darien Province, Panama, elevation 130 meters; William E. Duellman collector], Agalychnis litodryas: Duellman, 1968b, p. 4 [transfer of Phyllomedusa litodryas Duellman and Trueb, 1967, to Agalychnis Cope, 1864]. Diagnosis: This large species having fully webbed hands and feet differs from other Agalychnis by lacking pigment on the hands, feet, thighs, and flanks. Structurally it is most like spurrelli, which has bright yellow flanks, thighs, and extremities; furthermore, the dor- sum is uniformly green in litodryas, whereas the dorsum in spurrelli is green with black- bordered white spots. Description: Only the type specimen, an adult male, is known. This specimen has a snout-vent length of 70.2 mm. and the follow- ing proportions: tibia length/snout-vent length, 0.523; foot length/ snout-vent length, 0.392; head length/snout-vent length, 0.345; head width/ snout-vent length, 0.307, diameter of tympanum/ diameter of eye, 0.705. The head is as wide as the body, and the top of the head is flat. In dorsal profile the snout is acuminate. In lateral profile, the snout slopes from the eyes to the nostrils and is further inclined from the nostrils to the tip of the snout. The nostrils are protuberant laterally and are about two-thirds of the dis- tance from the eyes to the tip of the snout. The canthus is rounded and distinct; the loreal region is slightly concave, and the lips are thin and moderately flared. A thin dermal fold extends from the posterior corner of the orbit, covering the dorsal and posterior edges of the tympanum, to a point just behind the angle of the jaw; from there it continues pos- 1970 DUELLMAN: HYLID FROGS 129 tcriorly as a dermal flap to a point above the insertion of the arm. The tympanum is dis- tinct, posteroventral to the eye, and separated from the eye by a distance equal to one-third of the diameter of the tympanum. The upper arm is slender, and the forearm is robust. A narrow dermal fold extends from the elbow along the ventrolateral edge of the forearm and the fourth finger to the disc on the fourth finger. The fingers are short, and the discs are very large, all larger than the tympanum. The distal subarticular tubercles on the third and fourth fingers are large and round; the other subarticular tubercles are smaller and conical. The pollex is enlarged, has a flat, elliptical ventral surface, and bears a large, horny, non-spinous nuptial excres- cense. The fingers are about three-fourths webbed (fig. 28D). The web extends to the base of the penultimate phalaax on the first finger and medial edges of the second and third fingers, and to the discs on the other fingers. The hind limbs are slender; when the limbs are adpressed the heels over- lap by about one-third the length of the thighs. The tibiotarsal articulation extends to the nostril. There is no dermal fold along the outer edge of the tarsus, but a small dermal flap is present on the posteroventral surface of the heel. The tarsal fold is moderately strong and extends the full length of the tarsus. The inner metatarsal tubercle is large, flat, elliptical, and broadly visible from above. The toes are moderately long and slender. The discs are large, nearly as large as the tympanum. The subarticular tubercles are large and conical. Small supernumerary tu- bercles are present on the proximal segments of all toes, except the first. The toes are fully webbed; the web extends to the bases of the discs on all toes ( fig. 30D ) . The anal sheath is long, and the anal open- ing is directed ventrally at the level of the ventral surfaces of the thighs. The skin of the dorsum, chin, chest, and ventral surfaces of the limbs, except the thighs, is smooth, whereas the skin on the belly and ventral sur- faces of the thighs is moderately granular. The granules form a distinct row on the pos- teroventral edge of the thigh. The tongue is twice as long as wide and deeply notched pos- teriorly. It is free posteriorly for about one- third of its length. The dentigerous processes of the prevomers are narrow transverse ele- vations between the anterior margins of the small ovoid choanae. Ten teeth are present on each process. The vocal slits are small and lie along the posterior one-fourth of the rami of the jaws. The vocal sac is single, median, subgular, and not noticeably distensible. The general coloration consists of a uni- form green dorsum and unpigmented flanks and thighs (pi. 43, fig. 4). The dorsal surfaces of the head, body, forearm, thighs, shanks, tarsi, third and fourth fingers, and fourth and fifth toes are uniform pale green; the throat and belly are creamy white. A narrow yellow- ish white stripe extends along the inner edge of the shank, across the heel, and along the outer edge of the tarsus and fifth toe. A nar- row yellowish white stripe is present on the outer edge of the forearm and fourth finger. The flanks, anterior and posterior surfaces of the thighs, inner surfaces of the tarsi, upper arms, inner surfaces of forearms, first and sec- ond fingers, first, second, and third toes, and webbing lack pigment, so that these surfaces appear pale pinkish gray. The iris is dark red, and the palpebral membrane is reticulated with gold. The nuptial excrescence is dark gray. In preservative the dorsal surfaces of the body, forearms, hind limbs, fourth and fifth toes, and third and fourth fingers, are uni- form bluish green. The chin, chest, and belly are white; other ventral surfaces are creamy gray. The lines on the forearm and hind limbs are white. The one specimen that is known was con- fined in a cloth sack overnight; when it was first observed the following morning the dor- sum had changed from pale green to a dark olive-green. Tadpoles: The tadpoles of this species are unknown. Mating Call: The mating call consists of a single low-pitched "groan." In the one re- cording available the duration of the note is 0.15 of a second. The pulse rate is 105 pulses per second; the note has 16 pulses, and the last pulse is not intensified. The fundamental frequency is 104 cycles per second, and the dominant frequency is 1664 cycles per second (pi. 39, fig. 3). 130 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Natural History: The only known speci- men was found on a bush in a swamp at night. Agalychnis callidryas was breeding in the swamp, and individuals of Phyllomedusa ve- nusta were present there. Remarks: Structurally, Agalychnis lito- dryas is strikingly similar to A. spurrelli, which has a slightly higher and less sloping snout, somewhat smaller discs, and more supernu- merary tubercles. The most noticeable dif- ferences are in coloration; A. spurrelli has yellow flanks, thighs, hands, feet, and chin, whereas in litodryas, these structures lack pig- ment, except the chin which is white. Fur- thermore, litodryas lacks the black-bordered white spots on the dorsum that are always present on spurrelli. Etymology: The specific name alludes to the absence of flash-colors and is derived from the Greek litos meaning plain and the Greek Dryas, a tree nymph. Distribution: Currently this species is known only from eastern Darien Province, Panama (fig. 41). See Appendix 1 for the locality record of the one specimen examined. Genus Phyllomedusa Wagler Phyllomedusa Wagler, 1830, p. 201 [type species, Rana bicolor Boddaert, 1772, by original designation]. Pithecopus Cope, 1866b, p. 86 [type species, Phyl- lomedusa azurca Cope, 1862 ( = Phyllomedusa hypo- chondrialis Daudin, 1803) by original designation]. Hylomantis Peters, 1872, p. 772 [type species Hy- lomantis aspersa Peters, 1872, by monotypy]. Phrynomedusa Miranda-Bibeiro, 1923, p. 3 [type species, Phrynomedusa fimbriata Miranda-Bibeiro, 1923, by subsequent designation ( Funkhouser, 1957)]. Bradymedusa Miranda-Bibeiro, 1926, p. 104 [type species, Bradymedusa moschada Miranda-Bibeiro, 1926 ( =PhyIlomedusa rohdei Mertens, 1926), by sub- sequent designation (Funkhouser, 1957)]. Generotype: Wagler (1830, p. 201) pro- posed the generic name Phyllomedusa for Hyla bicolor Daudin, 1803 (=Rana bicolor Boddaert, 1772). Etymology: The generic name is derived from the Greek phyll, meaning leaf, and the Greek Medousa (Latin Medusa), apparently in reference to coelenterate medusae. The name alludes to the gelatinous egg-masses deposited on leaves of trees. Definition: Frogs of the genus Phyllo- medusa are small to large species and gener- ally have a green dorsum; some change to brown or orange-tan at night. The pupil is vertically elliptical and the iris varies from uniformly silvery white to orange-bronze with black reticulations. The palpebral membrane is not reticulated. The fingers and toes have rudimentary webbing or lack webs entirely; the terminal discs are small. The first toe is shorter than, equal to, or longer than the second toe; in those species having a long first toe, it is opposable to the others. The skin on the dorsum is smooth or rugose with or without osteoderms. Parotoid glands are absent in some species, but in most they are distinct and elevated. There is no integu- mentary-cranial co-ossification. The vocal sac is single, median, and subgular, or absent. The tongue is lanceolate and free posteriorly. Breeding males have brown horny nuptial ex- crescences on the thumbs. The skull is mod- erate to deep; the depth is more than 38 per cent of the length (figs. 42 and 43). The parietal plane is barely inclined anteroven- trally. The skull is characterized by a fronto- parietal fontanelle (narrow and elongate in some species and large and ovoid in others) and moderately developed squamosals with long posterior arms and short anterior arms that extend no more than one-third of the distance to the maxillaries. The quadrato- jugals are moderately robust or slender; in some small species they are not in bony con- tact with the maxillaries. The alary processes on the premaxillaries are well developed and extend dorsally or slightly posterodorsally. The maxillary bears a deep pars facialis, which in some species (small species are the exception) extends dorsally at the level of the palatine and connects with the short maxillary process of the nasal (fig. 42). The nasals are large, usually narrowly separated medially, and narrowly separated from, or in bony con- tact with the sphenethmoid. The canthal ridge is approximately parallel to the maxil- lary. The maxillary process of the nasal does not extend to the main axis of the maxillary, but is separated from the maxillary (fig. 43) or connects with the posterior process of the pars facialis. The sphenethmoid is well os- sified. The dentigerous processes of the pre- vomers are reduced or short and situated at a 1970 DUELLMAN: HYLID FROGS 131 slight angle or perpendicular to the midline. The pterygoids are robust and lack a bony connection with the prootics. The otic region is relatively small to moderate in size. Teeth are present on the premaxillaries and maxil- laries and lacking on the palatines and para- sphenoid in all species, whereas prevomerine teeth are present in some species and absent in others. The teeth are spatulate and bifid. The tadpoles have a ventral spiracle that is sinistral to the midline. Most of the known tadpoles are pelagic types with anterior mouths, deep fins, and slender caudal muscu- lature. Some, such as those of P. cochranae live in streams and show modifications for the stream environment. The mating call in those species having a voice is a single or double, relatively short, poorly modulated note. The haploid number of chromosomes is 13 ( known only in P. lemur and venusta). Composition of the Genus: Thirty-one species are currently recognized in the genus; one of these, P. burmeisteri, contains two sub- species. Several species groups are recog- nizable in the genus; generic names have been proposed for some of these groups (see fol- lowing section on Discussion). Most of the species inhabit South America; only two spe- cies, P. lemur and venusta, occur in Central America. Of these, 196 preserved frogs, seven skeletons, and two lots of tadpoles have been examined. Fig. 42. Dorsal (A), ventral (B), and lateral (C), views of the skull of PhyUomedusa venusta, K.U. No. 96514. x 2.5. Fig. 43. Dorsal (A), and lateral (B), views of the skull of PhyUomedusa lemur, K.U. No. 68629. X 5. 132 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Analysis of Characters: The two Middle American species of PhyUomedusa are repre- sentatives of two widely divergent species groups within the genus. Osteologically, P. lemur differs from venusta by having rela- tively less cranial ossification. Any meaningful analysis of characters must include the many South American species; such an account is beyond the scope of the present work. Distribution: The combined geographic ranges of the species of PhyUomedusa include the forested lowlands and moderate elevations on South America east of the Andes from the Caribbean (including Trinidad) to northern Argentina; in Central America the genus oc- curs in Costa Rica and Panama. Discussion: Included in the genus Phyl- lomedusa are several large species, such as bicolor, blombergi, edentida, orcesi, and ve- nusta; these species seem to form a natural group. Probably certain other species, such as burmeisteri, trinitatus, and vaillanti, belong with the preceding group. All of these species fit into a pattern of progressive specialization of the hands and feet for grasping. Several small species (ayeaye, centralis, cochranae, guttata, hypochondrialis, and roh- dei) have highly developed grasping feet. These species form a second, apparently nat- ural, group within the genus. Lutz (1966) resurrected Pithecopus Cope, 1866, for this group, but she also included such diverse spe- cies as tomopterna, trinitatus, and vaillanti in Pithecopus, thereby making the genus an unnatural and undefinable assemblage of spe- cies (see Duellman, 1968b). Funkhouser (1962) noted that three small, relatively unspecialized species [lemur, loris (=buckleyi), and medinae] seem to form a natural group that is distinct from other groups within the genus PhyUomedusa. Perhaps some, or all, of these species groups should be accorded generic status. However, an accurate assessment of variation and relationships must await the accumula- tion of much more data on most of the South American species, some of which are known only from the types. The two Central American species ob- viously are post-Pliocene immigrants from South America. Furthermore, the two species are members of diverse species groups, which must have differentiated in South America prior to invading Central America. PhyUomedusa lemur Roulenger Plu/Uoinedusa lemur Boulenger, 1882a, p. 425 [holotype, B.M.N.H. No. 1947.2.22.37 from "Costa Rica"; Higgens collector], Taylor, 1952c, p. 809. Funkhouser, 1957, p. 31. Duellman. 1968b, p. 6. Agalychnis lemur: Cope, 1887, p. 15 [transfer of PhyUomedusa lemur Boulenger, 1882a, to Agalychnis Cope, 1865a]. Gunther, 1901 ( 1885-1902), p. 291. Diagnosis: This small phyllomedusine frog can be distinguished from other Middle American members of the subfamily by lack- ing vomerine teeth, paratoid glands, and web- bing on the hands and feet and by having the first toe shorter than, and not opposable to, the second. By day lemur is pale green; at night it is orange-tan or brown. Agalychnis salt at or undergoes the same change in colora- tion. The latter can be readily distinguished from lemur by the presence of webbing and vomerine teeth and by having a red, instead of silvery white, iris. The only other Middle American phyllomedusine lacking webs is venusta, which is much larger and has the first toe longer than, and opposable to, the second and paratoid glands forming an elevated dor- solateral ridge. The diurnal coloration of lemur is much like that of Hyla uranochroa, a species having a horizontal pupil, red iris, and webbing. Description: This is a small species of PhyUomedusa; males attain a maximum snout- vent length of 40.8 mm., and females reach 50.6 mm. In a series of 20 males from Ta- panti, Cartago Province, Costa Rica, the snout- vent length is 30.1 to 34.7 (mean, 32.5) mm. The ratio of the tibia length to snout- vent length is 0.483 to 0.550 (mean, 0.513); the ratio of the foot length to snout-vent length is 0.320 to 0.357 (mean, 0.330); the ratio of head width to snout-vent length is 0.294 to 0.349 (mean, 0.315); and the ratio of the diameter of the tympanum to that of the eye is 0.351 to 0.511 (mean, 0.416). Two females from the same locality have snout- vent lengths of 39.5 and 41.6 mm. They do not differ significantly from the males in pro- portions, except that the ratio of the diameter of the tympanum to that of the eye is some- what larger, 0.465 and 0.487. Specimens from 1970 DUELLMAN: HYLID FROGS 133 TABLE 13 Comparison of Size and Certain Proportions, with Means in Parentheses, of Four Samples of PhijUomedusa lemur. Locality Sex N Snout-vent Length Tibia Length/ S-V L Head Width/ S-V L Tympanum / Eye Costa Rica: Tapanti $ Panama: Rio Changena .... tf- Fig. 46. Mouth of tadpole of Phyllomedusa lemur, U.S.C. No. 290. X 15. brown flecks and reticulations. The caudal fin is transparent with minute brown flecks. The mouth has a shallow lateral fold. The median part of the upper lip is bare. Other- wise, the mouth is bordered by two or three rows of small labial papillae; numerous pa- pillae are closely packed in the lateral fold. The upper beak is moderately deep and forms a broad arch. The lower beak is not so ro- bust; both beaks are finely serrate. There are two upper and three lower rows of teeth. The two upper rows are of equal length and extend laterally to the papillae. The second row is narrowly interrupted medially. The three lower rows are continuous; the first and sec- ond rows are nearly as long as the upper rows, whereas the third row is slightly shorter (fig. 46). Mating Call: The call of Phyllomedusa lemur consists of a short "Hack." The note is repeated at intervals of eight to 40 seconds. Each note has a duration of 0.20 to 0.29 (mean, 0.25) of a second. The pulse rate is 97 to 118 (mean, 108) pulses per second. The fundamental frequency varies from 108 to 120 (mean, 114) cycles per second, and the dominant frequency varies from 2272 to 2520 (mean, 2396) cycles per second (pi. 35, fig. 2). Natural History: Phyllomedusa lemur inhabits humid lower montane forests having an equable amount of rainfall throughout the year. Consequently, the frogs are active most of the year. Despite their prolonged period of activity, breeding seems to be concentrated in the months of April through July. Males call from the branches of bushes and low trees above shallow ponds. Remarks: One specimen is known from eastern Panama (U.S.N.M. No. 151079 from Cerro Mali, Darien Province). This specimen is much larger than any other known individ- ual of P. lemur. This specimen seems to rep- resent a continuation of the west-east cline for an increase in size. Funkhouser ( 1962, p. 588) named Phyllomedusa medinae from Rancho Grande, Estado Aragua, Venezuela. She diagnosed the new species as being much like P. lemur and loris; medinae is about the same size as the large individual of lemur from Cerro Mali; the holotype of medinae, an adult male, has a snout-vent length of 40 mm. whereas a female (S.U. No. 20379) has a snout-vent length of 49 mm., only slightly smaller than the snout-vent length of 50.6 mm. of the specimen from Cerro Mali The dorsal coloration of Phyllomedusa medinae includes white spots and dark flecks. Dark flecks are present in P. lemur, but white spots are absent. Possibly additional material from eastern Panama and northern Colombia will show that lemur and medinae are conspecific. Etymology: The specific name lemur is Latin and refers to the walking gait of this frog, which is not unlike that of the small monkey-like mammals, the lemurs. Distribution: Phyllomedusa lemur occurs in forested regions at elevations of 650 to 1600 meters on the Atlantic slopes of the highlands in Costa Rica and western Panama; this spe- cies also occurs on the Pacific slopes on Cerro La Campana and Cerro Mali in Panama (fig. 47). See Appendix 1 for the locality records of the 200 specimens examined. Phyllomedusa venusta Duellman and Trueb Phyllomedusa venusta Duellman and Trueb, 1967, p. 128 [holotype, K.U. No. 96150 from approximately 1 kilometer west-southwest of the junction of the Rio Mono and the Rio Tuira, Darien Province, Panama, elevation 130 meters; Charles W. Myers collector]. Duellman, 1968b, p. 6. Diagnosis: This large species belongs in that group of Phyllomedusa having the first toe longer than the second, possessing vomer- ine teeth and large parotoid glands, and lack- ing webbing on the hands and feet. Phyllo- medusa venusta is distinguished from other members of the group by having the following combination of characters: skin of dorsum 136 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 • P lemur ■ P i/enusta KILOMETERS 10' Fig. 47. Distribution of Middle American species of Phyllomedusa. pustulate, parotoid glands forming an angular ridge anteriorly and extending posteriorly nearly to the groin, chin and chest dark brown with white median spot, ventral and posterior surfaces of thighs brown with a white spot ventrolateral to the anus, and belly orange. Phyllomedusa venusta differs from the other Central American species, lemur, by having well-developed parotoid glands, the first toe longer than, and opposable to, the second, and in size. Phyllomedusa lemur is a small species lacking parotoid glands and having the first toe shorter than, and not opposable to the second. Description: Males of this large species attain a maximum snout-vent length of 86.3 mm.; the only known female has a snout-vent length of 97.7 mm. Three adult males from eastern Darien Province, Panama, have snout- vent lengths of 74.6 to 86.3 (mean, 82.0) mm.; the ratio of tibia length to snout-vent length is 0.450 to 0.479 (mean, 0.465); the ratio of foot length to snout-vent length is 0.330 to 0.369 (mean, 0.349); the ratio of head length to snout-vent length is 0.327 to 0.346 (mean, 0.333); the ratio of head width to snout- vent length is 0.334 to 0.353 (mean, 0.341), and the ratio of the diameter of the tympanum to that of the eye is 0.577 to 0.607 (mean, 0.591). The female differs by having a larger tym- panum; the tympanum/eye ratio is 0.633. The head is as wide as the body, and the top of the head is flat. In dorsal profile, the snout is acuminate. In lateral profile, in males, the snout gradually slopes from the eyes to the nostrils and then curves in a sharp incline to the tip of the snout, whereas in females it is truncate. The canthus is elevated and rounded. The nostrils are barely protuberant and are situated slightly closer to the tip of the snout than to the eyes. The loreal region is concave, and the lips are moderately heavy and not flared. There is no dermal fold be- hind the eye. The tympanum is distinct, al- though the dorsal and posterior edges are covered by skin. The tympanum is posterior to the eye and separated from it by a distance equal to the diameter of the tympanum. The upper arm is slender, and the forearm is moderately robust. A row of tubercles is present on the ventrolateral edge of the fore- arm. The fingers are long and lack webbing (fig. 48A). The fourth finger is barely shorter than the third. The discs are small; none is as large as the tympanum. The subarticular tubercles are large and conical. Two flat, 1970 DUELLMAN: HYLID FROGS 137 round, palmar tubercles are present, and one large elliptical tubercle is present on the base of the pollex. The pollex is slightly larger in males and bears a smooth, horny nuptial ex- crescence. The hind limbs are relatively short and moderately slender. The heels of the adpressed limbs barely overlap; the tibiotar- sal articulation extends to the posterior corner of the eye. Dermal flaps or tubercles on the heel are lacking, and the tarsal fold is absent. The inner metatarsal tubercle is flat, ovoid, and not visible from above. The toes are moderately long, slender, and unwebbed (fig. 48B ) . The discs are slightly smaller than those on the fingers. The subarticular tubercles are large and conical. Fig. 48. Hand (A) and foot (B) of Phyllome- dusa venusta, K.U. No. 96150. X 3. No distinct anal flap is present; the anal opening is directed posteroventrally at the level of the middle of the thighs. The skin on the dorsum and flanks is pustulate. The pustules are raised but flat, not conical. The dorsal surfaces of the forearms and dorsal and ventral surfaces of the hind limbs are tu- berculate; tubercles are arranged in rows on the edges of the shanks and tarsi. The skin on the throat, chest, belly, and underside of the forelimbs is granular. A large parotoid gland extends from the eye nearly to the groin. The gland forms an angular, longitudinal ridge on the anterior half of the body and a rounded ridge posteriorly. A large glandular area is present on the side of the neck above the in- sertion of the arm. The tongue is lanceolate and twice as long as wide; it is shallowly notched posteriorly and free behind for about one-third of its length. The dentigerous proc- esses of the prevomers are small and postero- medially inclined between the small, ovoid, choanae. The males have five teeth on each prevomerine process; the female has three and four teeth on each prevomerine process. Vo- cal slits and a vocal sac are absent. The general coloration is green above and brown on the throat and chest and orange on the belly (pi. 41, fig. 2). The dorsum is uni- form green, darkest on the dorsal part of the body and somewhat paler on the shanks, tarsi, forearms, and sides of the head. The flanks are green with minute pale blue flecks, es- pecially in the groin. The chin, chest, anterior part of the belly, and the ventral surfaces of the thighs are dark grayish brown with white spots. One large spot is present on the proxi- mal ventral surface of the thighs in all speci- mens. In one individual, a series of smaller spots is present more distally on the thigh. All specimens have a white spot anterome- dially on the chest; one individual has several smaller spots on the throat and chest, and another has two small spots on the throat (fig. 49). The posterior part of the body is pale, dull orange; some orange flecks are present on the posterior surfaces of the thighs. The anterior surfaces of the thighs and tarsi, ventral surfaces of shanks, and distal pha- langes of the first and second fingers and first, second, and third toes are pale pinkish orange with dull greenish brown markings. 138 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 The ventral surfaces of the hands and feet are white. A white stripe extends along the edge of the lower lip and continues around the base of the arm to a point about mid- length of the shank. A narrow, creamy white or pale yellow stripe is present on the outer edge of the forearm and fourth finger, and a creamy white line is present above the anus. The iris is golden orange with black reticula- tions. The palpebrum is clear, and the nup- tial excrescences are dull grayish brown. In preservative the dorsum is dark blue and the parotoid glandular areas are slightly darker blue. The flanks are blue with black- bordered white spots. The edge of the lower lip, the stripe on the anterior part of the flank, the stripe along the edge of the fore- arm, the stripe above the arnus, the ventral surfaces of the upper arm, and the median ventral surfaces of the forearm arc white. The ventral surfaces of the shank, and anterior surfaces of the thighs are creamy white with Fig. 49. Ventral coloration in Plujllomedusa venusta, K.U. No. 96150. X 1. vertical purplish blue bars on the latter. The ventral and posterior surfaces of the thighs and ventral surfaces of the tarsi, forearm, hand, and feet are brown. The chin, chest, and anterior part of the belly are dark brown; the rest of the belly is dull creamy tan. Tadpoles: The tadpoles of this species are unknown. Mating Call: Because vocal slits and a vocal sac apparently are absent, it is presumed that this species has no mating call, but a male emitted a short release call when grasped (pi. 37, fig. 3). Natural History: The five known speci- mens were found on vegetation in a swamp, where the species probably breeds, although no breeding activity was noted. Remarks: PhijUomedusa venusta is the only Central American representative of that group of large PhijUomedusa having the first toe longer than the second. The other species are found in South America east of the Andes. The absence of information on the colors in life and on the tadpoles in the majority of these species precludes any meaningful in- terpretation of interspecific relationships at this time. Etymology: The specific name is derived from the Latin venustus, meaning like Venus, beautiful and elegant, and alludes to the col- oration of the frog. Distribution: Presently Plujllomedusa venusta is known only from eastern Panama (fig. 47). See Appendix 1 for the locality records of the five specimens examined. Genus Hemiphractus Wagler Hemiphractus Wagler, 1828, column 743 [type species, Hemiphractus spixii Wagler, 1830 (=Rana scutata Spix, 1824) by subsequent designation (Peters, 1862, p. 146)]. Noble, 1926, p. 19 [synonymy of Ccrathi/la with Hemiphractus]. Ceratht/Ia Jimenez de la Espada, 1871, p. 63 [type species Cerathyla bubalus Espada, by subsequent des- ignation (Myers and Carvalho, 1945, p. 21 )]. Generotype: Rana scutata Spix, 1824, by subsequent designation. Wagler, in 1826 and 1830 used the name Hemiphractus spixii, which Peters ( 1862 ) showed to be the same as Rana scutata Spix, 1824. Thus, the species now known as Hemiphractus scutatus (Spix) is the generotype. 1970 DUELLMAN: HYLID FROGS 139 Etymology: The generic name is derived from the Greek prefix hemi, meaning half, and the Greek phraktos, meaning protected, and refers to the helmet covering what seems to be about the anterior half of the animal. Definition: Frogs of the genus Hemi- phractus are of medium size and have a large triangular head modified into a bony helmet. Dermal appendages are present on the eyelids and tip of the snout in some species. The skin is partially adherent to the neural spines, which are conspicuous dorsally. Webbing is lacking on the hands and feet. The dorsum is variously mottled tan, brown, or olive. The pupil is horizontal, and the palpebral mem- brane is clear. The vocal sac is single, me- dian, and subgular. Breeding males appar- ently lack horny nuptial excrescences. The skin on the dorsum is smooth and not co- ossified on the head. The skull is highly modified, nearly twice as wide as long, triangular in dorsal view, and nearly completely roofed by moderately rugose bones, which are marked by small, circular pits (fig. 50). The dorsal roofing bones are expanded so as to roof the skull; the nasals and frontoparietals have a common point of suture. Likewise, the premaxillaries, maxillaries, and quadratojugals have broad, thin, dorsal flanges broadly sutured to the dermal roofing bones. Consequently, the orbit is completely bordered by bone. A small fossa is present at the point of junction of the maxillary, quadratojugal, and squamosal. The posterior arm of the squamosal is greatly ex- panded into a posterolateral process or "horn." The prevomer is a slender arcuate bone bear- ing odontoids but lacking teeth. The robust, transverse palatines bear odontoids and nearly meet medially. The pterygoid is exceptionally robust and fully articulated to the maxillary, squamosal, and prootic. The parasphenoid has long alary processes and lacks odontoids. The mandible is strong, and the dentary bears odontoids, the anterior one of which is greatly enlarged. Teeth are present on the maxillaries and premaxillaries. The known life histories indicate that the young develop directly from eggs carried on the back of the female. The mating calls and number of chromosomes are unknown. Composition of Genus: Probably five spe- cies are recognizable in the genus; all are considered to be monotypic. Only one species occurs in Central America; of it, 33 preserved frogs and two skeletons have been examined. Fig. 50. Dorsal (A), ventral (B), and lateral (C) views of the skull of Hemiphractus panamensis, K.U. No. 93509. X 2. 140 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Distribution: Upper Amazon Basin from Peru northward, Pacific slopes of Colombia and northwestern Ecuador, Pacific and Carib- bean slopes in eastern Panama, and Carib- bean slopes in western Panama and probably adjacent Costa Rica. Discussion: Although Noble (1926, p. 19) considered Cerathyla to be a synonym of Hemiphractus, most subsequent workers have recognized two genera. The latter genus lacks expanded digital pads and has the eyes some- what closer to the snout than in Cerathyla, which has expanded digital pads. Dr. Alan E. Leviton has been studying these frogs for a number of years and has strongly advised that Ceratohyla should not be recognized. Cursory examination of some of the species and selected skeletal material, including Hemiphractus scutatus, indicates that Levi- ton's suggestion is reasonable. Hemiphractus panamensis (Stejneger) Cerathyla panamensis Stejneger, 1917, p. 31 [holo- type, U.S.N. M. No. 55320 from Signal Loma, 5 kilo- meters south of Santa Isabel, Colon Province, Panama; Charles G. Holland collector]. Diagnosis: This moderate-sized species differs from all other members of the genus by the following combination of characters: helmet rugose, posterior border of helmet deeply indented, dermal flaps present on up- per eyelid, moderately long dermal proboscis triangular in section, and calcars present. Hemiphractus panamensis is immediately dis- tinguishable from other Middle American hy- lids by having a large triangular helmet lack- ing co-ossification and by having the skin partially adherent to the neural spines of the vertebrae. Description: Males of this medium-sized species attain a maximum snout-vent length of 56.3 mm.; and females reach 58.7 mm. In a series of 11 males from the Serrania de Pirre, Darien Province, Panama, the snout-vent length is 48.5 to 56.3 (mean, 52.8) mm.; the ratio of tibia length to snout-vent length is 0.473 to 0.530 (mean, 0.506); the ratio of foot length to snout-vent length is 0.428 to 0.479 (mean, 0.455); the ratio of head length to snout- vent length is 0.422 to 0.458 (mean, 0.442); the ratio of head width to snout- vent length is 0.451 to 0.511 (mean, 0.489), and the ratio of the length of the tympanum to that of the eye is 0.740 to 0.980 (mean, 0.874). Five females from the same locality have snout-vent lengths of 63.0 to 68.7 (mean, 66.0) mm. and much smaller tympani; the ratio of the length of the tympanum to the diameter of the eye is 0.523 to 0.667 (mean, 0.580). The head is as wide as, or slightly wider than, the body. The top of the head is smooth; the temporal region is greatly expanded pos- terolaterally to form a point. The width of the head between the points is less than the width at the angles of the jaws; the ratio of the two measurements varies from 0.740 to 0.932 (mean, 0.874). In dorsal profile the snout is acuminate; in lateral profile, the snout slopes from the interorbital region to the margin of the lips. The canthus is barely evident and rounded; the loreal region is slightly concave and inclined laterally to the margins of the lips. A bony ridge extends from the posterior corner of the eye to the tip of the posterolateral point of the skull. The tympanum is entirely distinct and much higher than long. The tympanum is directed posterolaterally and is separated from the eye by a distance equal to twice the length of the tympanum. A large, triangular, dermal flap is present below the tympanum at the angles of the jaws. A large, fleshy, tubercle is present on the edge of each upper eyelid, and a pointed, fleshy, triangular ( in transverse sections) proboscis is present. The eyes are relatively small and widely separated, and the nostrils are directed anterodorsally at a point about midway between the eyes and the tip of the snout. The arms are moderately long and robust; an axillary membrane is absent. A small tu- bercle is present on the ventral surface of the elbow, and a low, fleshy fold extends along the ventrolateral edge of the forearm. There is no transverse dermal fold on the wrist. The fingers are long and moderately slender and bear small discs; the width of the disc on the third finger is slightly less than the length of the tympanum. The thumb is longer than the second finger. The subarticular tubercles are moderately large and conical; in some in- dividuals, the distal tubercle on the third and fourth fingers are distinctly bifid. The super- 1970 DUELLMAN: HYLID FROGS 141 Fie. 51. Hand (A) and foot (B) of Hemiphractus panamensis, K.U. No. 107417. X 3. numerary tubercles are conical; they are dis- tinct in some specimens and barely evident in others. A low, indistinct, palmar tubercle is present. The prepollex is moderately en- larged and in breeding males does not bear a horny nuptial excrescence. A vestige of a web is present between the second and third and between the third and fourth fingers (fig. 51A). The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fifth of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A fleshy calcar is present on the heel, but a tarsal fold is lacking. The inner metatarsal tubercle is elongately ovoid and elevated; a small sub- conical outer metatarsal tubercle is present. The toes are moderately long and slender and bear discs that are somewhat smaller than those on the fingers. The subarticular tu- bercles are large and conical; and the super- numerary tubercles are high and conical. The toes are webbed basally (fig. 51B). The anal opening is directed posteriorly near the upper level of the thighs; the opening is covered by a broad, fleshy sheath. The skin on the belly is granular; that on the dorsum of the body and shanks and on the ventral surfaces of the limbs is smooth. The skin on the dorsal surfaces of the forearms, thighs, and flanks is tubercular. The skin on the head is not co-ossified with the underlying bones. The skin is partially adherent to the neural processes of the vertebrae, which are promi- nent dorsally. The tongue is broadly cordi- form, shallowly notched behind, and barely free posteriorly. The palatines form a trans- verse ridge across the roof of the mouth. The prevomers form a pair of posteromedially in- clined processes between the small, ovoid choanae. Odontoids are present on palatines and prevomers; likewise, small serrations are 142 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 present on the dentary and a pair of large odontoids are present at the symphysis of the lower jaws. The vocal slits are small and nearly transverse near the angles of the jaws. The vocal sac is single, median, subgular. The general coloration of Hemiphractus panamensis usually consists of a pale brown dorsum with darker brown markings (pi. 44, fig. 2). The dorsum varies from pale yellow- ish tan to grayish brown or olive-gray. Dorsal markings vary from just a few small dark flecks to one or two chevron-shaped marks and/or a dark brown dorsolateral stripe. In most individuals dark transverse bands are evident on the dorsal surfaces of the limbs. The posterior surfaces of the thighs are dark brown with a diffuse creamy yellow stripe separating the dark color on the posterior surfaces of the thighs from the coloration on the dorsal surfaces. The throat and chest are dark brown or black. A white spot is present medially on the chest; in many individuals this is extended anteriorly to form a median stripe or series of dashes on the throat. There are some small white spots on the lower lip and a few white tubercles on the chest. The rest of the venter is brown with an orange tint. The tongue and the lower inside edge of the lip is yellowish orange. The iris is gray with a yellowish cast above and a pale red dish brown suffusion below and a narrow horizontal brown stripe through the pupil. The palpebral membrane is clear. Small individuals tend to have paler and more contrasting patterns than do large adults. Some large females are nearly uniform dark grayish brown above. The coloration of the upper part of the iris varies from yellow to pale green. In preservative the dorsum is tan to dark brown with darker brown markings evident or not. The venter is brown with white flecks and spots, and the posterior surfaces of the thighs are dull brown. Tadpoles: Hemiphractus panamensis has direct development of the young, which are discussed in a following section on natural history. Mating Call: No recordings of the call of this species are available. Myers ( 1966, p. 71) noted that one individual emitted a loud cat-like squall when handled and that similar noises were heard from several indi- viduals in a bag. Natural History: Hemiphractus pana- mensis inhabits humid montane or cloud for- ests characterized by an abundance of atmo- spheric moisture throughout the year. The frogs are always found either on the ground or relatively close to the ground. Some indi- viduals have been found in leaf litter on the forest floor by day. Individuals observed at night usually are on sticks, leaves or ferns at a height of less than one meter above the ground. However, one individual was found on a tree trunk about two meters above the ground, and another at a similar height was looking out from the base of a bromeliad on a tree trunk at night. These observations in- dicate that the frog is nocturnal and that it seeks shelter amidst the leaf litter on the forest floor by day. One individual having a snout-vent length of 48.5 mm. contained an adult dendrobatid frog (Colostethus pratti) and a gastropod hav- ing a diameter of 10 mm. Another individual having a snout- vent length of 50.4 mm. con- tained an adult Ttychoglossus festae. Roth Colostethus and Ptijchoglossus are principally diurnal; the appearance of these species in the diet of Hemiphractus is an apparent con- tradiction to the nocturnal habits of the spe- cies as evidenced by our observations in the field. Roth of the prey items inhabit the leaf litter on the forest floor; perhaps, in the early morning hours or at dusk the activity of the animals overlap that of Hemiphractus. Fur- thermore, it is entirely possible that Hemi- phractus in some cases, is active, perhaps only on the forest floor by day. On the other hand, possibly Hemiphractus feeds on such prey when they are sleeping. Myers (1966, p. 70) described the aggres- sive behavior in this species: "These frogs made no attempt to escape unless unduly prodded. Rather, when picked up or tapped on the snout, they gaped their mouth and sometimes slightly arched the body by throw- ing the head up and back. The effect was striking owing to a bright yellow-orange tongue (yellow in one), as well as to the large mouth and wierd head shape. . . . The display is not all bluff, for several readily bit any object placed close to the mouth, and one 1970 DUELLMAN: HYLID FROGS 143 even fastened its jaws around the head of a neighboring Cerathyla [=Hemiphractus]. By offering a finger to the first Cerathyla cap- tured, I was made painfully aware of the two sharp odontoids (on front of lower jaw) that proved capable of piercing human flesh; one must wait patiently for the grip to be released, else pry apart the jaws." Additional observa- tions on this species in Panama substantiate the behavior reported by Myers, who made the point that the bright yellow-orange tongue is an integral part of the mouth-gaping be- havior. In this species, the female carries the eggs on the back in the manner described for Hemiphractus bubalus described by Boulen- ger ( 1903 ) . The eggs apparently encapsulate on the dorsum and adhere strongly to the skin. The resulting modification of the dermis of the dorsum consists of a series of depres- sions (pi. 7), which apparently are extremely superficial, because the skin of the back, con- taining these scars is sloughed off after the young have departed (Stejneger, 1917, p. 33). The number of scars on the back of two fe- males (U.S.N.M. No. 55320 with a snout-vent length of 60.0 mm., and B.Y.U. No. 19142 with a snout-vent length of 61.2 mm.) is 14 and 12, respectively. Another female (K.U. No. 93503 with a snout-vent length of 58.7 mm. ) contained twelve large, yolked eggs with an average diameter of about 6 mm. Noble (1917, p. 808) reported on a histo- logical examination of the gills and their at- tachment in the specimens reported by Stejne- ger ( 1917 ) . Examination of the female col- lected more recently (B.Y.U. No. 19142) substantiates the data presented by Noble and provides some further information. At the time that I examined this specimen ( Janu- ary 18, 196S), two young were attached to the female and five additional young were con- tained in the jar with the female. The back of the female is deeply pitted; the gills of each juvenile frog are embedded in these pits; two pairs of white cords extend from the gills to the throat of the froglet ( pi. 2 ) . In a froglet having a snout-vent length of 15 mm., the cords are about 7 mm. in length and attached to the disc-like gill that is about 6 mm. in diameter. Superficially, the gills appear to be attached to the frog by two cords, but careful examination reveals that what appears to be a single cord is actually a pair of closely as- sociated cords. The cord enters the throat on either side of the hyoid and just anterior to the pectral girdle. The gills are closely ad- herent to the disc-like base of the depression in the back of the female; the gills seemingly are separated from the skin by a thin gelati- nous layer, which Noble (1917, p. SOS) stated to be the egg membranes. Noble showed that the cord contained blood vessels and striated muscle and that the blood vessels anastomosed in the gills. Be- cause gills apparently are separated from any vascular tissue in the female, it is most un- likely that the developing frog derives either nourishment or oxygen from the parent. In- stead, the gills apparently serve two functions — to obtain oxygen from the atmosphere, and to provide a firm attachment to the female for purposes of transportation. The young individuals associated with B.Y.U. No. 19142 seem to be nearly fully developed. In each, the cranium is reasonably well ossified; the neural processes of the verte- brae are evident dorsally, and the triangular fleshy proboscis is evident. The eyes are well developed, but a large amount of yolk re- mains in the gut. The gills of Gastrotheca, the young of which develop within a dermal pouch, func- tion for oxygen exchange with the tissues of the female. Certainly the behavioral trait of carrying the eggs on the back, as it is exhib- ited by Cryptobatrachus and Hemiphractus, is advantageous, because the females can pro- vide some care for the eggs. Such parental care may, in fact, be a necessity. Direct de- velopment circumvents the disadvantages of an aquatic larval stage; however, the adult frogs are obliged to provide some method of transportation for the developing froglets un- til they are capable of surviving alone. The gill-attachment observed in Hemiphractus ob- viously is the key to the success of the trans- portation of the young. The development and exact function of these so-called "gills," be it attachment, respiration, or both, must await the acquisition of additional females with early-term eggs. It will be most interesting to determine whether or not the cords are homol- ogous with the gills of hylid tadpoles. 144 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 82° 80° 78° 10° - ( i i • "> \ "0% • L^ • • ^V ) (. ^W-^, ♦ 0 < \ \ 8° - • r 0 100 ^ 1*1 > -' KILOMETERS <(> (7 i 1 i 10 82° 80° 78° Fig. 52. Distribution of Hcmiphractus panamensis. The meager evidence of life history sug- gests that the breeding season is prolonged in this species. The two females bearing young were collected on May 20 and Sep- tember 15, whereas the female with large eggs was obtained on December 13. Remarks: The taxonomic status of the various named kinds of Hcmiphractus is open to question; this genus is being studied by Alan E. Leviton, who suggested ( in lift. ) that Hcmiphractus panamensis probably is most closely related to fasciatus on the Pacific slopes of Ecuador; panamensis is somewhat intermediate between proboscidea and fascia- tus. Etymology: The specific name is in ref- erence to Panama, the country from which the type specimen originated. Distribution: Hemvphr actus panamensis occurs at elevations between 300 and 1600 meters on the Caribbean slopes of the high- lands of Panama and on the Pacific slopes of the highlands in eastern Panama (fig. 52). The species is known from the Serrania de Pirre and the Serrania de Darien in eastern Panama, but it was not found on the Serrania del Sapo. See Appendix 1 for the locality records of the 35 specimens examined. Anotheca Smith Anotheca Smith, 1939, p. 190 [type species by original designation, Gastrotheca coronata Stejneger, 1911 (=iHyla spinosa Steindachner, 1864)]. Generotype: Hyla spinosa Steindachner, 1864. Gunther (1859) assigned juveniles from Mexico and Costa Rica to Opisthodelphys ovi- fera ( Lichtenstein and Weinland, 1854), and Boulenger (1882a) assigned the same speci- mens to Nototrema oviferum. Stejneger (1911) had an adult male bearing the char- acteristic cranial spines and thus was able to demonstrate that the Middle American species was distinctly different from the South American Opisthodelphys {^Gastrotheca) ovifera; he named the Middle American spe- cies Gastrotheca coronata. Smith (1939) demonstrated that females of coronata lacked the pouch characteristic of Gastrotheca and proposed the generic name Anotheca for coro- nata. Dr. Charles F. Walker called my attention to Steindachner's ( 1864 ) description of Hyla 1970 DUELLMAN: HYLID FROGS 145 spinosa, and Walker, upon examination of the holotype of spinosa in Vienna, concluded that it probably was the same as the frogs as- signed to Anotheca coronata. Through the courtesy of Dr. Josef Eiselt, I borrowed the holotype of Hyla spinosa and compared it with the numerous examples of Anotheca coronata. On the basis of the distinctive col- oration, structure of the feet, integumentary- cranial co-ossification, and spines on the squa- mosal (holotype of spinosa is a juvenile hav- ing a snout-vent length of 40 mm.), there is no doubt that the holotype of Hyla spinosa is the same as the frogs that have been called Anotheca coronata. Consequently, the ge- nerotype of Anotheca is Gastrotheca coronata Stejneger, 1911, which is a junior synonym of Hyla spinosa Steindachner, 1864. The type locality of "Brazil" given by Steindachner probably is in error, because the species is unknown south of central Panama. Etymology: The generic name is derived from the Greek an-, meaning without, and the Greek theke, meaning container, in reference to the absence of a brood pouch. Definition: The frogs in this genus are moderately large and are characterized by integumentary-cranial co-ossification and a casqued head that has spines dorsally and is wider than long (fig. 53). The dorsum is brown and the sides and belly are dark brown or black. The pupil is horizontally elliptical, and the palpebral membrane is clear. The fingers essentially lack webbing, and the toes are about one-half webbed. Breeding males lack horny nuptial excrescences on the thumbs. The skin is co-ossified with the un- derlying cranial elements on the top of the head, except the sphenethmoid, and in the lo- real region, but not on the lips. The maxil- laries and premaxillaries are unmodified. The skull is completely roofed. The frontoparietals extend laterally over the otic region. The an- terior arm of the squamosal extends to, or nearly to, the maxillary. The quadratojugal articulates with the maxillary. Long, slender, pointed, curved spines are present on the canthal ridge of the nasal, outer edges of the frontoparietals, and on the anterior and pos- terior arms of the squamosals. A few small spines are present on the maxillary below the orbit. The palatine is slender, and the medial ramus of the pterygoid is robust and in bony contact with the prootic. Narrowly spatulate, bifid teeth are present on the premaxillaries, maxillaries, and prevomers, and absent on the palatines and parasphenoid. The tadpoles de- velop in bromeliads or water-filled cavities in trees, have two upper and two lower rows of teeth, and feed on frog eggs. The supposed mating call consists of a long series of like notes. The haploid number of chromosomes is 12. Composition of the Genus: The genus is monotypic; 200 preserved specimens, five skel- etons, and four lots of tadpoles have been examined. Distribution: Anotheca occurs on the At- lantic slopes of Veracruz and Oaxaca, Mexico, on the Caribbean slopes of Costa Rica and western Panama, and on the Pacific slopes of central Panama. Discussion: Anotheca apparently is closely related to Gastrotheca, from which it differs by lacking a brood pouch in the females. The skulls of casque-headed Gastrotheca, such as G. nicefori, resemble that of Anotheca, except that the latter has the long spines, which are absent in Gastrotheca. Anotheca probably evolved from an early Gastrotheca stock that was isolated in Middle America, whereas the main differentiation of Gastrotheca took place in South America. Anotheca spinosa (Stejneger) Opisthodelphys ovifera (nee Notodelphys ovifera Lichtenstein and Weinland, 1854): Gunther, 1859, p. 117. Brocchi, 1882, p. 47. Hyla spinosa Steindachner, 1864, p. 539 [holotype, N.M.W. No. 16101 from "Brazil"; Johann Natterer collector] . Nototrema oviferum (part): Boulenger, 1882a, p. 418. Gunther, 1901 ( 1885-1902), p. 288. Nototrema marsupiatum ( nee Hyla marsupiata Dumeril and Bibron, 1841 ) : Diaz de Leon, 1904. Gastrotheca coronata Stejneger, 1911, p. 287 [holotype, U.S.N.M. No. 48279 from Palomo, Valle de Orosi, Cartago Province, Costa Bica; C. Picado T. collector], Kellogg, 1932, p. 133. Anotheca coronata: Smith, 1939, p. 190 [proposed genus Anotheca for Gastrotheca coronata Stejneger, 1911]. Smith and Taylor, 1948, p. 70. Taylor, 1952c, p. 797. Anotheca spinosa: Duellman, 1968c, p. 195 [syn- onymized Gastrotheca coronata Stejneger, 1911, with Hyla spinosa Steindachner, 1864] 146 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 53. Dorsal ( A ) and lateral ( B ) views of the skull of Anothcca spinosa. (K.U. No. 84899). x 4. Diagnosis: Adults of this species are readily distinguished from all other Middle American hylids by the presence of integu- mentary-cranial co-ossification in combination with sharp, dorsally pointed, spines on the canthal, supratympanic, and occipital ridges. The diagnostic color pattern of dark brown with black venter and flanks bordered by white is present in small juveniles, which lack the cranial spines. Description: Males of this species attain a maximum known snout-vent length of 68.5 mm., and females reach 73.0 mm. In a series of 20 males from eastern Mexico, the snout- vent length is 59.8 to 65.1 (mean, 60.7) mm.; the ratio of tibia length to snout-vent length is 0.461 to 0.515 (mean, 0.486); the ratio of foot length to snout-vent length is 0.403 to 0.463 (mean, 0.430); the ratio of head length to snout-vent length is 0.339 to 0.361 (mean, 0.352); the ratio of head width to snout- vent length is 0.339 to 0.373 (mean, 0.357), and the ratio of the diameter of the tympanum to that of the eye is 0.716 to 0.873 (mean, 0.810). Eight females from the same region have snout-vent lengths of 57.7 to 69.6 ( mean, 62.2) mm.; in proportions, the females differ from the males only by having slightly larger tympani, 0.714 to 0.938 (mean, 0.833). Few specimens are available from the southern part of the range, where individuals apparently reach a larger size than in the north. The largest specimens of both sexes (male, 68.5 mm. and female, 73.0 mm.) are from Panama. The head is about as wide as the body, and the top of the head, between the supra- 1970 DUELLMAN: HYLID FROGS 147 orbital ridges, is flat. In dorsal profile, the snout is acutely rounded, and in lateral pro- file, it is truncate. The skin on the top of the head is co-ossified with the underlying cranial elements, which are modified to form an ele- vated canthal ridge, a supraorbital ridge, a supratympanic ridge, and a transverse occipi- tal ridge. In large adults dorsally directed spines are present on the supraorbital, supra- tympanic, and occipital ridges, and in some specimens, low spines are present on the canthal ridges. In some specimens, some or all of the spines are covered by skin, but in some individuals sharp-tipped bony spines protrude through the skin. In juveniles, hav- ing snout-vent lengths of less than 25 mm. there is no evidence of bony ridges or of spines. In specimens having snout-vent lengths of 40 to 50 mm., ridges and spines are beginning to develop. For example, one individual having a snout-vent length of 45 mm. has the skin on the top of the head co-ossified with the underlying cranial ele- ments. The canthal ridges and supratympanic ridges are present, and blunt, skin-covered spines are present on the supratympanic ridge. Another individual having a snout- vent length of 47 mm. also has a few small spines in the area of the supraorbital ridges and has a pair of spines on the occiput, but definitive supraorbital and occipital ridges are absent. In large adults having a maximum development of spines a short, spiny postor- bital ridge is present. In these specimens, the spines are closely placed and continuous from the nostrils along the canthal, supraorbital, and supratympanic ridges to the transverse occipital ridge (fig. 54). In some specimens, minute spines are present medial to the pri- mary row of spines. The snout is moderately long, and the nostrils are barely protuberant and situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The internarial region is slightly de- pressed. The loreal region is concave, and the lips are moderately thick and slightly flared. In large adults the skin is co-ossified in the loreal region but not on the lips. The upper part of the tympanum is concealed by the supratympanic ridge; otherwise, the tym- panum is distinct and elevated; it is sepa- rated from the eye by a distance equal to Fig. 54. Head of Anothcca spinosa (K.U. No. 58076) showing extreme condition of cranial spines. X 3. about three-fourths of the diameter of the tympanum. The arms are long and slender; there is no row of tubercles along the outer edge of the forearm, but a weak transverse dermal fold is present on the wrist. The fingers are long and slender and bear moderately large discs; the width of the disc on the third finger is equal to about two-thirds of the diameter of the tympanum. The subarticular tubercles are moderately small and subcorneal; in some specimens, the distal tubercle on the fourth finger is bifid. The supernumerary tubercles are distinct and conical. In most specimens, they are arranged in a single row on the proximal segments of each digit, but in some individuals the tubercles are crowded on the proximal segment of the second finger. A double palmar tubercle is present. A low, flat, elliptical tubercle is present on the pre- pollex, which is only moderately enlarged and in breeding males does not bear a horny nuptial excrescence. Webbing is lacking be- tween the first and second fingers, and rudi- mentary between the others (fig. 55A). The legs are moderately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A thin, transverse dermal fold is present on the heel, and a distinct tarsal fold extends the full length of the tar- 148 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 55. Hand (A) and foot (B) of Anotheca spinosa (K.U. No. 58075). X 3. sus. The inner metatarsal tubercle is moder- ately large, ovoid, and barely visible from above. A small, conical outer metatarsal tu- bercle is present. The toes are moderately long and slender and bear discs that are only slightly smaller than those on the fingers. The subarticular tubercles are small and conical, and the supernumerary tubercles are small, conical, and arranged in a single row on each digit. The toes are less than half webbed (fig. 55B). The webbing extends from the distal end of the antepenultimate phalanx of the first toe to the distal end of the ante- penultimate phalanx of the second, from the base of the penultimate phalanx of the sec- ond to the base of the antepenultimate pha- lanx of the third, from the base of the penulti- mate phalanx of the third to the base of the antepenultimate phalanx of the fourth and on to the base of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally at the midlevel of the thighs. An elon- gate anal sheath is present; the anal opening is bordered on either side by a vertical der- mal fold. The skin on the dorsum, exclusive of the head, and the ventral surfaces of the limbs, except the thighs, is smooth; that on the throat, belly, and proximal posteroventral sur- faces of the thighs is granular. In some speci- mens, small tubercles are present on the dorsal surfaces of the forearm. The tongue is broadly cordiform, shallowly notched behind, and barely free posteriorly. The dentigerous proc- esses of the prevomers are relatively small, rounded elevations between the small, round choanae. There are five to 10 teeth on each process and a total of 10 to 19 prevomerine teeth; the average number of teeth in males is 12.6 and in females, 12.5. No vocal slits are evident in the specimens that I have exam- ined; furthermore, I have not been able to ascertain the definite prescence of a vocal sac. The general coloration of Anotheca spi- nosa is tan or brown above with dark brown or black on the side of the head and on the flanks (pi. 44, fig. 3). The dorsal ground color varies from pinkish tan to pale reddish brown or grayish brown. The tip of the snout and the ground color of the limbs is the same as the color on the dorsal surfaces of the head and body. A tan or pale gray vertical 1970 DUELLMAN: HYLID FROGS 149 bar is present on the lips anterior to the eye. Otherwise, the entire side of the head, the tympanum, and most of the axillary region are dark brown or black. Most of the venter, likewise, is dark brown or black; extensions of the dark ventral color are present on the flanks, usually as broad diagonal bars. The dorsal and posterior surfaces of the thighs, the ventral surfaces of the shanks, and the dorsal and ventral surfaces of the feet are marked with dark brown or black transverse bars. Black transverse markings are also present on the arms and on the fingers and toes. All of the black markings are narrowly outlined with white or pale creamy yellow. The iris is reddish bronze or coppery brown with or without fine black reticulations. The coloration of juveniles resembles that of the adults, except that the limbs are more distinctly banded, especially ventrally, in the juveniles. The distinctive dark brown or black lateral markings, narrowly outlined by white are present, and the venter is dark brown. In preservative, the dorsal ground color varies from dull reddish tan to dark gray. The lateral dark markings and the bands on the limbs are black, narrowly outlined by creamy white. Tadpoles: The tadpoles of Anotlieca spi- nosa were first described by Taylor ( 1954a ) . Starrett (1960a, p. 32) described some tad- poles which she thought to belong to Ano- theca spinosa and questioned the identity of the tadpoles described by Taylor. Robinson (1961, p. 495) noted that on the basis of tadpoles collected in Veracruz, Mexico, Tay- lor's tadpoles were correctly identified, whereas those described by Starrett did not belong to Anotheca spinosa. I have examined all of the tadpoles in question and have stud- ied three additional lots of tadpoles, including young that were metamorphosed from these tadpoles. I concur with Robinson that the tadpoles that he and Taylor assigned to Anotheca spinosa are correctly identified, whereas those described by Starrett can not be assigned definitely to any known species of hylid. A series of tadpoles in developmental stage 25 have body lengths of 6.8 to 8.8 (mean, 7.2) mm. and total lengths of 18.0 to 22.8 (mean, 19.7) mm.; a series of specimens in develop- mental stage 33 have body lengths of 10.5 to 12.5 (mean, 11.7) mm. Four tadpoles in developmental stage 36 have body lengths of 13.7 to 16.0 (mean, 15.3) mm. The largest tadpole examined is in developmental stage 38 and has a body length of 17.1 mm. and a total length of 45.3 mm. A typical tadpole in developmental stage 33 has a body length of 11.7 mm. and a total length of 27.5 mm. The body is moderately depressed and nearly flat above. The body is noticeably wider than deep and is widest posteriorly. In dorsal profile the snout is trun- cate, and in lateral profile it is rounded. The eyes are small, situated dorsally, and directed dorsolaterally. The nostrils are dorsal and situated about midway between the eyes and the tip of the snout. The spiracle is short and located ventrolaterally on the body; the spi- racular opening is directed posteriorly at a point slightly more than midway between the snout and the posterior edge of the body. The anal tube is long. The caudal musculature is relatively heavy and extends to the tip of the rounded tail. The fins are fleshy and shal- low; the ventral fin is slightly deeper than the dorsal fin (fig. 56). In life the tadpoles are dark brown above and bluish gray below; the caudal muscula- ture is brown, and the caudal fins are tan. In preservative, the entire tadpole is dull brown. The mouth is anteroventral; its width is equal to about one-half of the greatest width of the body. The mouth is bordered by a single row of moderately large, blunt papillae. A faint lateral fold is present, and in this area a few small, blunt papillae are present. The beaks are immense and bear fine serrations. The upper beak extends laterally to the edges of the lip, and the ventral beak is broadly V-shaped. There are two upper and two lower rows of teeth. The second upper row is broadly interrupted medially. The teeth are relatively small and not continuous in the rows, especially the upper ones. All rows are about equal in length (fig. 57). Tadpoles in developmental stage 25 have a nearly continuous first upper row of teeth and many teeth in the second upper row. Tadpoles in developmental stage 33 and later have a reduced number of teeth in the upper 150 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 56. Tadpole of Anotheca spinosa (K.U. No. 60016). x 3. rows and show some reduction in the number of teeth in the lower rows. Mating Call: I have never observed Anotheca spinosa calling, nor have I traced an unknown call directly to an individual of this species. The apparent absence of vocal slits and a vocal sac possibly precludes the pres- ence of a mating call in this species. How- ever, I have heard an unknown frog call at Vista Hermosa, in northern Oaxaca, Mexico, and the same call on the Rio Changena, Bocas del Toro Province, Panama. Anotheca spinosa is the only species of frog, whose voice I do not definitely know, that occurs at both of these localities. I provide a brief description of the call recorded at Vista Hermonsa, in hope that a future worker might determine definitely whether or not this is the call of Anotheca spinosa. One recording was obtained. The call con- sists of a series of notes, "boop-boop-boop," that are intensified in the latter part of the call. One hundred and seventy-eight notes were produced in 56 seconds. Each note has a duration of about 0.1 of a second and the interval between notes is about 0.3 of a sec- ond. The pulse rate is 220 pulses per second. The audiospectrogram (pi. 24, fig. 3), shows that the call is made up of four distinct har- monics. The lowest harmonic at about 540 cycles per second is the dominant frequency; Fig. 57. Mouth of tadpole of Anotheca sjnnosa (K.U. No. 60016). x 17. other harmonics are at about 1080, 1620, and 2160 cycles per second. Natural History: Anotheca spinosa in- habits cloud forests, where apparently this spe- cies is active throughout the year. I have ob- tained adults in February, March, June, and August at Vista Hermosa, Oaxaca, Mexico. Juveniles have been found in March and Au- gust. Taylor ( 1954a) noted the egg eating habits of the tadpoles of this species. He obtained tadpoles from bromeliads at Moravia, Cartago Province, Costa Rica. Robinson ( 1961 ) found tadpoles of this species in a water-filled tree cavity on the south slopes of Volcan San Mar- tin, Veracruz, Mexico. I have also found tad- poles of this species on Volcan San Martin and in tree holes at Vista Hermosa, Oaxaca, Mex- ico. Young tadpoles ( developmental stage 25 ) contained mosquito larvae in the gut, whereas tadpoles in developmental stage 33 and later contained frog eggs in the gut. As noted by Taylor (1954a), the eggs contained in the gut do not seem to have been damaged in the process of ingestion. Some eggs in various early stages of development (up to gastrola- tion) were found undamaged in the gut of tadpoles. On the other hand, the mosquito larvae show evidence of having been chewed. Perhaps, the apparent change in diet from young to older developmental stages is cor- related with the reduction of teeth in the later stages. In one water-filled tree hole on the south slope of Volcan San Martin, the content of decomposing organic matter in the water re- sulted in a thick aqueous solution in which the tadpoles were living. In another cavity at Vista Hermosa, the amount of water was so slight that it was barely possible for all of the tadpoles to be completely submerged at one time. Evidently, the tadpoles of Anotheca spinosa are able to survive in water in which the oxygen content is extremely low. At Moravia, Cartago Province, Costa Rica, 1970 DUELLMAN: HYLID FROGS 151 where Taylor found the tadpoles of this spe- cies in bromeliads, it is possible that the tad- poles were feeding on eggs of another species of frogs. In Costa Rica, Hijla zeteki is known to lay eggs in bromeliads. At the Mexican localities where tadpoles of Anotheca spinosa have been found, I know of no other species of frog that deposits its eggs in tree holes, although Hijla dendroscarta lays its eggs in bromeliads. Perhaps, the tadpoles of Ano- theca spinosa ingest eggs deposited by females of their own species. If this be true, the tad- poles are acting as a major control on the size of the population. Obviously, further study is needed on the ecology of this species. Two young that were metamorphosed from tadpoles that were collected on Volcan San Martin, Veracruz, Mexico, have snout-vent lengths of 15.9 and 19.7 mm. Remarks: Taylor (1954a, p. 594) com- mented on some minor differences between two Costa Rican specimens and several indi- viduals from Veracruz, Mexico. The differ- ences that he noted between these popula- tions, with regard to the cranial spines and ridges, apparently are the result of different degrees of development in different individ- uals and not populational differences. Al- though I have examined six specimens from Costa Rica and Panama, I am unable to find any noteworthy differences between these in- dividuals and the many specimens available from eastern Mexico. Etymology: The specific name is Latin meaning thorny and refers to the spines on the dorsal periphery of the head. Distribution: Anotheca spinosa is known from elevations of S00 to 1800 meters on the Atlantic slopes of the Sierra Madre Oriental in Veracruz and northern Oaxaca, and in the Sierra de los Tuxtlas in southern Veracruz, Mexico; this species also occurs at elevations from 300 to 1200 meters on the Caribbean slopes of Costa Rica and western Panama, and one individual is known from El Valle on the Pacific slopes of Panama (fig. 58 ).5 See Appendix 1 for the locality records of the 209 specimens examined. '" Drs. Roy W. McDiarmid and Charles F. Walker have seen a photograph of an individual taken near San Vitio on the Pacific slopes of extreme eastern Puntarenas Province, Costa Rica. Genus Gastrotheca Fitzinger Gastrotheca Fitzinger, 1843, p. 30 [type species, llyla marsupiata Dumeril and Bibron, 1841, by mono- typy]- Notodelphys Lichtenstein and Weinland, 1854, p. 373 [type species, Notodelphys ovifera Lichtenstein and Weinland, 1854; preoccupied by Notodelphys Allman 1847 (Crustacea)]. Nototrema Giinther, 1859, p. 115 [replacement name for Gastrollicca Fitzinger, 1843]. Opisthodelphis Giinther, 1859, p. 117 [substitute name for Notodelphys Lichtenstein and Weinland, 1854; preoccupied by Notodelphys Allman, 1847 (Crustacea)]. Generotype: The first usage of the ge- neric name is in Fitzinger ( 1843, p. 30 ) : "Gastrotheca . . . Am. . . . Hijla marsupiata Dum. & Bib." There is no other indication; thus, Hijla marsupiata Dumeril and Bibron, 1841, is the type species of Gastrotheca. Etymology: The generic name is derived from the Greek gastros, meaning belly, and the Greek theke, meaning container, and re- fers to the brood pouch. Giinther ( 1859, p. 115) noted Fitzinger's error of position and stated: "Fitzinger appears to have believed in the existence of a pouch on the belly; his denomination is derived from yaor))p belly, and Ojjkn, used by the old anatomists for the brain-pan; therefore I think myself justified in not accepting his name." Giinther proposed the name Nototrema (Greek notos, back) in reference to the dorsal brood pouch. Unfor- tunately, the Law of Priority necessitates the usage of the misleading name Gastrotheca. Definition: The following definition ap- plies specifically only to those species inhab- iting Middle America. These are large frogs with prominent heads. The head is casqued and the skin is co-ossified with the underlying dermal bones in one Central American species {nice fori) and several South American spe- cies (angustifrons, iceinlandi, fulvorufa, and ovifera); in some other species (ceratophrys and cornutum) the skull is exostosed but co- ossification is absent. The webbing is reduced or absent on the hands, and the feet are no more than two-thirds webbed. The dorsum is unicolor brown, green, or gray or marked by darker longitudinal marks or transverse lines. The pupil is horizontal, and the palpe- bral membrane is clear. The vocal sac is single, median, and subgular; breeding males 152 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 58. Distribution of Anotheca spinosa. of some species have horny nuptial excres- cences, whereas these are lacking in other species. Females have a dorsal brood pouch opening as a longitudinal slit posterior to the sacrum. The skull of Gastrotheca ceratophrys is broader than long, deep, and well ossified (fig. 59). The frontoparietals are expanded later- ally so as to form a flange over the orbit and part of the otic region; there is no fronto- parietal fontanelle. The sphenethmoid is large and well ossified anteriorly so as to separate the nasals posteriorly. The nasals are well ossified laterally and in contact anteriorly. The maxillary process of the nasal is broadly sutured to the pars facialis of the maxillary; the two elements form a complete anterior margin for the orbit. The premaxillary is ro- bust and has a long, slender alary process and a large palatine process. The maxillary is ro- bust and has a high pars facialis. The squa- mosal is in broad bony contact with the crista parotica; the anterior arm of the squamosal is robust and articulates with the maxillary. The quadratojugal is robust and in bony contact with the maxillary. The prevomer is moder- ately developed; the anterior end lies dorsal to the pars dentalis of the maxillary. The dentigerous processes of the prevomers are small, posteromedially inclined, and widely separated medially. The palatine is moder- ately robust and has a ventral ridge. The pterygoid is robust and broadly articulated with the maxillary, prootic, and squamosal. Teeth are present on the premaxillaries, max- illaries, and prevomers but absent on the pala- tines and parasphenoid. All of the dermal roofing bones, the squamosal, and the pars facialis of the maxillary are exostosed. Apparently in all species the eggs develop 1970 DUELLMAN: HYLID FROGS 153 Fig. 59. Dorsal (A), ventral (B), and lateral (C) views of the skull of Gastrotheca ceratophrys, K.U. No. 104361. x 2.5. in the brood pouch in the female. In Gastro- theca marsupiatum there is an aquatic larval stage, whereas in other species, in which the life history is known, an aquatic larval stage is absent; the eggs undergo direct develop- ment. The mating calls of the Central Ameri- can species consist of a series of short notes (ceratophrys) or of a primary note followed by a series of shorter secondaries (nicefori). The haploid number of chromosomes is 14 (known only in G. ceratophrys). Composition of Genus: About nineteen species comprise the genus. The greatest di- versity is in northwestern South America. Two species occur in lower Central America; of these, 14 preserved specimens and one skele- ton have been examined. Analysis of Characters: The two Cen- tral American species differ in a number of structural details, which are enumerated in the diagnoses. The feet of Gastrotheca cerat- ophrys have more webbing than do those of nicefori (fig. 60). The skin of the skull is co-ossified in nicefori and not in ceratophrys. The calls of the two species are noticeably different; that of ceratophrys consists of one to five short notes, and that of nicefori con- sists of a primary note followed by two to six secondary notes (pi. 36). Distribution: Southeastern highlands of Brazil, moderate to high elevations from Bo- livia to Colombia and Venezuela, and low to moderate elevations in Panama. Discussion: The two Central American species of Gastrotheca are members of two divergent species groups in South America. Currently all too little is known about the sys- tematics of this interesting group of hylids. Three decades ago, Helen T. Gaige was ac- tively working on these frogs; some 20 years ago, Charles F. Walker inherited the prob- lem. Since then much new material has ac- cumulated, but no synthesis of the group has appeared. Gastrotheca ceratophrys (Stejneger) Hyla ceratophrys Stejneger, 1911, p. 286 [holo- type, U.S.N.M. No. 47705 from the upper Rio Pequeni, Panama Province, Panama; A. H. Jennings collector]. Gastrotheca ceratophrys: Duellman, 1966b, p. 265 [transfer of Hyla ceratophrys Stejneger, 1911, to Gas- trotheca]. Diagnosis: This large species (males to 81 mm.) has long slender legs (tibiotarsal articulation extends well beyond the tip of the snout), thin transverse dermal ridges on the dorsum, triangular dermal flaps on the upper eyelids, skin on head not co-ossified, and the feet about two-thirds webbed. The other Central American Gastrotheca is smaller 154 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 60. Hands and feet of Middle American Gastrotheca. A and C. G. ceratophrtjs, K.U. No. 101535. B and D. G. nicefori, K.U. No. 111991. x 2.5. 1970 DUELLMAN: HYLID FROGS 155 ( males to 73 mm.) and has shorter legs (tibio- tarsal articulation extends only to the eye), no transverse dermal folds on dorsum or triangu- lar flaps on eyelids, skin of head co-ossified, and toes only half webbed. The only other Central American hylid having a triangular dermal flap on the upper eyelid is Hemi- phractus panamensis, which has a triangular head, fleshy proboscis, neural processes pro- truding through skin on the dorsum, and virtually no webbing. Description: Males of this large species attain a maximum known snout-vent length of 81.0 mm., and females reach 72.5 mm. In a series of four males from Panama, the snout- vent length is 66.4 to 81.0 (mean, 74.2) mm.; the ratio of tibia length to snout-vent length is 0.561 to 0.615 (mean, 0.596); the ratio of foot length to snout-vent length is 0.447 to 0.464 ( mean, 0.453 ) ; the ratio of head length to snout-vent length is 0.311 to 0.359 (mean, 0.338 ) ; the ratio of head width to snout-vent length is 0.348 to 0.386 (mean, 0.369), and the ratio of the diameter of the tympanum to that of the eye is 0.419 to 0.430 (mean, 0.426). One adult female having a snout-vent length of 72.5 mm. has a somewhat larger tympanum than that in males; the ratio of the diameter of the tympanum to that of the eye is 0.465. The head is nearly as wide as the body, and the top of the head is slightly concave. In dorsal profile, the snout is bluntly rounded, and in lateral profile it is steeply inclined from the nostrils to the margins of the lips. The snout is rather short; the distance be- tween the anterior corner of the eye and the nostril is about equal to the diameter of the eye. The nostrils are slightly protuberant at a point about three-fourths of the distance from the eyes to the anterior margin of the lips. The snout is high; the canthus is angu- lar, and the loreal region is barely concave and inclined ventrolaterally. The lips are moderately thick and barely flared. A mod- erately large triangular dermal flap is present on the edge of the upper eyelid; in some indi- viduals the flap is bifid terminally. A thin dermal fold extends posteriorly from the eye, above the tympanum, and posteriorly onto the sides of the body. The fold obscures the upper edge of the tympanum, which other- wise is barely discernible and separated from the eye by a distance equal to about twice the diameter of the tympanum. The arms are long and rather slender; an axillary membrane is absent. There is no row of tubercles on the ventrolateral edge of the forearm, nor is there a distinct transverse fold on the wrist. The fingers are long and slender and bear large discs; the width of the disc on the third finger is equal to half again the diameter of the tympanum. The subarticular tubercles are large and subcorneal; none is bifid. Supernumerary tubercles, when present on the hand, are barely evident on the proxi- mal segments of the second and third fingers. No palmar tubercle, as such, is present. The prepollex is barely enlarged and in breeding males bears a diffuse horny, nuptial excres- cence. The thumb is longer than the second finger, which is noticeably shorter than the fourth finger; webbing is lacking between the fingers (fig. 60A). The legs are long and slender; the heels of the adpressed limbs over- lap by about one-fourth of the length of the shank. The tibiotarsal articulation extends well beyond the tip of the snout. A trans- verse dermal fold is present on the heel, and in most individuals a small tubercle or calcar is evident on the heel. A weak, thin tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is small and ovoid; no outer metatarsal tubercle is present. The toes are long and slender and bear discs that are slightly smaller than those on the fingers. The subarticular tubercles are large and round; small supernumerary tubercles are present on the proximal segments of the third, fourth, and fifth toes. The toes are about two- thirds webbed (fig. 60C). The webbing ex- tends from the distal end of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the distal end of the antepenulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. The opening is covered by a short, broad, anal shealth. A pair of large tubercles is present below the 156 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 anal opening. The skin on the dorsum is smooth, except for a few small pustules and a series of low, transverse ridges. There are eight to 12 ridges across the back, beginning on the head, anterior to the orbit. Usually the second, but sometimes the third, ridge crosses the eyelid. The skin on the dorsal surfaces of the limbs and the ventral surfaces of the shanks is smooth. The skin on the throat, belly, and ventral surfaces of the arms and thighs is granular, and the skin on the flanks is aerolate. Many small tubercles are present on the side of the head between the orbit and the tympanum. The opening of the brood pouch in the female is about midway between the sacral hump and the anal open- ing; the opening is puckered and triangular in shape. The tongue is broadly cordiform, shallowly notched behind, and not free pos- teriorly. The dentigerous processes of the prevomers are transverse or barely postero- medially inclined, medially separated, eleva- tions between the moderately small, quad- rangular choanae. There are seven to nine teeth on each process and a total of 14 to 18 (mean, 16.3) prevomerine teeth. No vocal slits are evident, but males have a single, me- dian, subgular vocal sac that is moderately distensible. The general coloration of Gastrotheca cer- atophnjs is tan or brown with darker, nar- row transverse lines on the body and bars on the dorsal surfaces of the limbs (pi. 45, fig. 2). When active at night, these frogs usually are pale yellowish tan, grayish tan, or olive-tan. They have usually eight to 15 dark brown, narrow, transverse lines on the back and a somewhat wider dark brown dor- solateral stripe that begins on the supratym- panic fold and extends to the groin. The dorsal surfaces of the limbs are colored like the body and are marked by numerous nar- row transverse bars. There are five or six bars on the thigh, four or five on the shank, and three or four on the foot. The flanks and belly are creamy white. The anal region usu- ally is dark brown, and the posterior surface of the thighs are pale brown. By day the frog usually becomes darker brown with still darker brown markings. The flanks change to creamy tan with brown venation. The throat is brown, and the belly and ventral surfaces of the limbs are pinkish tan or pale brown. There are distinct vertical bars on the lip, which are most evident by day when they are dark brown and usually separated by a broad, conspicuous creamy white or pale yellow spot below the eye. There is a faint creamy yellow anal stripe. The webbing on the feet is brown. The iris is bronze peripher- ally and creamy yellow or olive-green medi- ally. The palpebrum is clear. In preservative the dorsum varies from tan to dull gray or dark brown with darker brown or nearly black transverse lines. The flanks usually are somewhat lighter and mot- tled or venated with brown. In those speci- mens killed by night, the venter is creamy white, whereas in those killed by day the venter is tan or dull brown. The posterior surfaces of the thighs varies from creamy tan to pale reddish brown. The white subocular spot is most evident in those individuals killed by day. Tadpoles: The development of Gastro- theca ceratophrys is unknown. One female (K.U. No. 77016) contains nine eggs in the brood pouch. Each egg has a diameter of about 12 mm. and contains a small embryo having distinct eyes and a long tail bud (fig. 61 ) . It is unknown whether these eggs would have developed into tadpoles, as in Gastro- theca marsupiatum, or if they would have de- veloped directly into small frogs, such as is the case in most species of Gastrotheca. It is most likely that the aquatic larval stage is absent in this species. Mating Call: The call of Gastrotheca ceratophrys is a loud "bop." The call is rem- iniscent of the sound made from the pulling of a cork from a bottle of champagne. Fre- quently the call consists of a single note; other times two notes are given. One individual was heard to produce a single note followed by an interval of about one minute and then three notes in quick succession. Usually the interval between call groups is eight to 12 minutes. The duration of each note in one recording obtained is 0.08 of a second and the interval between the notes is 0.60 of a second. The notes consist of three harmonics at approximately 800, 1600, and 2400 cycles per second; the lowest harmonic is the domi- 1970 DUELLMAN: HYLID FROGS 157 Fig. 61. Dorsal view of a female Gastrolheca ceratophrys (K.U. No. 77016) with the brood pouch opened on the left side to show the developing em- bryos, and the membranes removed from one egg. X 1.5. nant frequency. Each note noticeably di- minishes in pitch ( pi. 36, fig. 1 ) . Natural History: Gastrotheca cerato- phrys inhabits tropical rain forest and low montane forest characterized by high humid- ity throughout the year. These large frogs are strictly nocturnal and arboreal. Individ- uals have been observed at heights of 12 meters above the ground, and the numerous voices from much greater heights indicate that this species is an inhabitant of the tree- tops in the tall forests. Calling males were heard at Almirante, Bocas del Toro Province, Panama, on March 23, at the Rio Changena and Rio Claro, Bocas del Toro Province, in May, and at Laguna and Tacarcuna, Darien Province, in July. The single gravid female was obtained on July 5, 1963, at Laguna. Males characteristically call from branches or from vines between trees, high above the ground. This has proved to be one of the most elusive frogs in lower Central America. Al- though an adult female was obtained at La- guna in July, 1963, the voices, now known to belong to this species, were not associated with Gastrotheca ceratophrys at that time. Instead, we unsucessfully searched for the "tree-top bopper" until a calling male was found near Almirante, on March 23, 1965. Al- though the characteristic loud voice of this frog belies its presence in a given area, the acquisition of specimens is extremely difficult. A week spent on the Rio Changena in May, 1966, resulted in the collection of one speci- men, although several males were heard call- ing from high elevations in the trees every night. Remarks: Cochran and Goin (1970) ap- parently overlooked Stejneger's name and de- scription of Hyla ceratophrys and the fact that Duellman ( 1966b ) placed this species in the genus Gastrotheca; they referred the speci- men from Tacarcuna, Darien Province, Pan- ama (U.S.N.M. No. 141795), to Gastrotheca cornutum (Boulenger, 1808a). Another speci- men (F.M.N.H. No. 54718) from the Rio San Joaquin, Departamento Cauca, Colombia, was discussed at length by Cochran and Goin, who compared it with the holotype of Gas- trotheca cornutum (B.M.N.H. No. 1947.2.22.- 49) from Cachabe, Esmeraldas Province, Ecuador. Cochran and Goin noted that their Colombian specimen differed from the type of cornutum by having more webbing and by having definitive rows of tubercles arranged transversely on the back; furthermore, they noted some discrepancies in the coloration. A comparison of the Panamanian specimens with the description and illustration of Gas- trotheca cornutum (Boulenger, 1898a, p. 124, pi. 18) confirms the differences noted by Cochran and Goin. It seems most likely that the specimen from Colombia is referable to Gastrotheca ceratophrys, which probably is a species distinct from, but closely related to, Gastrotheca cornutum in Ecuador. Etymology: The specific name is derived from the Greek keras, meaning horn, and the Greek pliryne, meaning toad. The name, in reference to the dermal "horn" above the eye is used in the sense of the generic name for the large South American leptodactylids char- acterized by having a fleshy horn over each eye. Distribution: Gastrotheca ceratophrys 158 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 82° 80° 78° 10' • G ceratophrys o G. nicefori ' TV icr Fig. 62. Distribution of the Central American Gastrotheca. occurs at elevations at less than 1500 meters on the Caribbean slopes in western and cen- tral Panama and on the Pacific slopes in east- ern Panama and Colombia (fig. 62). See Appendix 1 for the locality records of the 12 specimens examined. Gastrotheca nicefori Gaige Gastrotheca nicefori Gaige, 1933, p. 1 [holotype, U.M.M.Z. No. 73242 from Pensilvania, Departamento Caldas, Colombia; Hermano Niceforo Maria collector]. Diagnosis: This moderately large species (males to 73 mm.) has short legs (tibiotarsal articulation extends to the eye), the skin of the head co-ossified and the feet about half webbed. The other Central American species, G. ceratophrys, lacks co-ossification, is larger (males to 81 mm.), and has the feet two- thirds webbed and the tibiotarsal articulation extends well beyond the tip of the snout; furthermore, ceratophrys has transverse der- mal folds on the dorsum and triangular dermal flaps on the upper eyelids. Other casque- headed Middle American hylids differ by having spines on the head (Anotheca), broad labial shelves and a prenasal bone ( Triprion ) , or a spatulate snout and spade-like inner metatarsal tubercles (Ptemohyla). Description: Males of this moderately large species attain a maximum snout-vent length of 73.5 mm., and females reach 82.0 mm. In a series of three males from Darien Province, Panama, the snout-vent length is 58.8 to 73.5 (mean, 66.6) mm.; the ratio of tibia length to snout-vent length is 0.490 to 0.522 (mean, 0.508); the ratio of foot length to snout-vent length is 0.433 to 0.479 (mean, 0.460); the ratio of head length to snout-vent length is 0.331 to 0.352 (mean, 0.340); the ratio of head width to snout-vent length is 0.371 to 0.395 (mean, 0.381), and the ratio of the diameter of the tympanum to that of the eye is 0.474 to 0.569 (mean, 0.507). No females are available from Central America. The head is as wide as the body, and the top of the head is concave. The skin is co- ossified with the underlying cranial elements; a distinct, but low transverse occipital ridge is evident, and a lateral bony supratympanic ridge is present. In dorsal profile, the snout is bluntly rounded; in lateral profile, the snout is abruptly inclined from the nostril to the 1970 DUELLMAN: HYLID FROGS 159 margin of the lip. The snout is moderately short; the distance from the anterior corner of the eye to the nostril is slightly greater than the diameter of the eye. The nostrils are barely protuberant at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is angular, and the loreal region is concave and inclined laterally to the moderately thin, slightly flared lips. A bony ridge extends posteriorly from the eye above the tympanum, and posterior to the ridge a dermal fold continues onto the side of the body. The upper edge of the tympanum is obscured by the tympanic crest; otherwise, the tympanum is distinct and separated from the eye by a distance equal to half again the diameter of the tympanum. The arms are long and moderately robust; an axillary mem- brane is absent. The forearms are devoid of a row of tubercles, but a distinct dermal fold is present on the wrist. The fingers are mod- erately long and robust and bear large discs; the width of the disc on the third finger is equal to half again the diameter of the eye. The subarticular tubercles are large and round; none is bifid. Small, conical super- numerary tubercles are present on the proxi- mal segments of the second, third, and fourth fingers. No distinct palmar tubercle is evi- dent. The prepollex is moderately enlarged and in breeding males bears a faint nuptial excrescence. The thumb is longer than the second finger, which is noticeably shorter than the fourth. Webbing is lacking between the first and second fingers, whereas the other fingers are barely webbed basally (fig. 60B). The hind limbs are moderately short and ro- bust; the heels of the adpressed limbs over- lap by about one-fifth of the length of the shank. The tibiotarsal articulation extends to the eye. A thin transverse dermal fold is present on the heel, but tubercles and a calcar are absent. The inner metatarsal tubercle is low, flat, and elliptical. No distinct outer metatarsal tubercle is present. The toes are long and slender and bear discs that are nearly as large as those on the fingers. The sub- articular tubercles are moderately large and round; faint supernumerary tubercles are present on the proximal segments of each digit. The toes are about half webbed (fig. 60D). The webbing connects the first and second toes at the level of the distal end of the penultimate phalanx of the second to the base of the antepenultimate phalanx of the third, from the base of the penultimate pha- lanx of the third to the base of the antepenul- timate phalanx of the fourth and from the middle of the antepenultimate phalanx of the fourth to the middle of the penultimate pha- lanx of the fifth toe. The anal opening is directed posteriorly near the upper level of the thighs; it is cov- ered by a short, narrow anal sheath and bordered below by two moderately large tu- bercles. The skin on the dorsum is aerolate, and that on the head is co-ossified. The skin on the throat, belly, and ventral surfaces of the thighs is granular; elsewhere, the skin on the venter is smooth. The tongue is nearly round, barely notched posteriorly, and not free behind. The dentigerous processes of the prevomers are small, narrowly separated ele- vations between the small round choanae. The three males have six to eight teeth on each process and a total of 13 to 16 (mean, 14.3) prevomerine teeth. The vocal slits ex- tend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and only moderately distensible. The general coloration of Gastrotheca nice- fori consists of a tan or pale grayish brown dorsum with dark brown flanks and concealed surfaces of the limbs ( pi. 45, fig. 1 ) . The fol- lowing descriptions of coloration are taken from the field notes of Charles W. Myers. K.U. No. 101538— By day all exposed dorsal surfaces were silvery gray with white and a few brownish spots sparsely and irregularly scattered on the dorsum. An ill-defined bronze stripe extends from the eye to the arm and barely includes the tympanum in its width. A pale pink line extends from above the tym- panum to the groin. Extensive areas of dark blue are present in the axilla, on the under- sides of the arms, on the posterior part of the flank into the groin, and onto the anterior sur- face of the thigh, on the posterior surface of the thigh, the ventral surface of the shank, and on to the inner side of the top of the foot, and on the webs of the hand and feet. In addition, the anterior part of the flank bears dark striations. The throat and adjacent 160 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 part of the chest is silvery gray becoming darker gray over the rest of the ventral sur- faces. The iris is pale gray. After dark the specimen became brown above, and the white spots and pink line became pale brown, whereas this brown spot that had been present by day became blackish brown. The iris changed to pale grayish brown. The ventral surfaces also darkened. K.U. No. 101539 — The dorsum is yellowish brown with a few blackish brown spots. An indefinite yellow line separates the dorsal color from the darker color on the flanks. The flanks and concealed surfaces of the limbs and venter are dark brown, darkest on the flanks and posterior surfaces of the thighs. No blue color was observed. The iris is pale brown. This specimen did not exhibit meta- chrosis. K.U. No. 111991 — The dorsum was pale grayish brown at night and changed to a medium brown by day. The flanks, groin, and anterior and posterior surfaces of the thighs are dark brown, almost black on the thighs, with a few small touches of pink on the flanks and a barest tinge of blue on the posterior surfaces of the thighs. The venter is pale dirty grayish brown. The iris is pale grayish brown with very fine black reticulations. In preservative, the dorsum is grayish tan with scattered small brown spots on the back and dorsal surfaces of the limbs. The flanks and anterior and posterior surfaces of the thighs are dark brown. The venter is dull grayish brown. Tadpoles: The early development of Gas- trotheca nicefori is unknown; presumably, the species undergoes direct development and aquatic larvae are absent. Mating Call: The call of Gastrotheca nicefori consists of a series of chicken-like "clucks." The call consists of a moderately long primary note and two to six shorter sec- ondary notes. In one recording, three call groups were emitted in a period of eight seconds, followed by a 12 second interval and one more call group. The duration of the primary note varies from 0.5 to 0.6 of a sec- ond and of the secondaries from 0.15 to 0.20 of a second. There are 80 to 90 pulses per second; the fundamental frequency is at ap- proximately 87 cycles per second, and the dominant frequency is at about 957 cycles per second (pi. 36, fig. 2). Natural History: The limited informa- tion on the ecology of this species has been gleaned from the field notes of Charles W. Myers, who collected the only Central Ameri- can specimens. He obtained two specimens from cloud forests on Cerro Cituro in the Serrania de Pine, Darien Province, Panama, in January, 1966. Both were found at night; one was on a vine-covered stump, and the other one was calling from a bromeliad- choked limb of a tree about 12 meters above the ground. Another individual was found about five meters above the ground at night in the Serrania del Sapo on April 23, 1967. Remarks: Two of the Panamanian speci- mens were compared with the holotype of Gastrotheca nicefori by Charles F. Walker and myself; no distinctive structural differ- ences could be found. The holotype is badly faded so that color comparisons were mean- ingless. It is interesting to note that in Panama, this species is known only from the Serrania del Sapo and the Serrania de Pirre, whereas Gastrotheca ceratophrys occurs in the Cordil- lera de San Bias and Serrania del Darien in eastern Panama. Thus, on the basis of very limited data the geographic ranges of the two species seem to be complementary; further- more, G. ceratophrys apparently occurs at elevations notably lower than those at which nicefori is found. Etymology: The specific name is a pat- ronym for Hermano Niceforo Maria, who has contributed so much to our knowledge of Colombian herpetology. Distribution: Gastrotheca nicefori occurs at elevations between 800 and 1100 meters in the Serrania de Pirre and Serrania del Sapo in extreme eastern Panama and at these and higher elevations in the Andes of central Co- lombia (fig. 62). See Appendix 1 for the locality records of the three specimens examined. Genus Phrynohyas Fitzinger Phrynohyas Fitzinger, 1843, p. 30 [type species, Hyla zonata Spix, 1824 ( =Rana vcnulosa Laurenti, 1768) by monotypy and declaration of the Interna- tional Commission on Zoological Nomenclature (Opin- ion No. 520, 1958)]. 1970 DUELLMAN: HYLID FROGS 161 Acrodijtes Fitzinger, 1S43, p. 30 [type species, Hijla venulosa Daudin, 1803 ( =Rana venulosa Laurenti, 1768) by monotypy; generic name suppressed by the International Commission on Zoological Nomenclature (Opinion No. 520, 1958) for purposes of the Law of Priority, but not for those of the Law of Homonymy]. Scytopis Cope, 1862 [type species, Scytopis hcbcs Cope, 1862, by monotypy]. Generotype: The determination of the status of the names applicable to the frogs in this genus has been one of the most chaotic cases of nomenclatural confusion in herpetol- ogy. Duellman (1956a) considered that the frogs previously referred to Hijla venulosa were generically separate from Hyla and pre- sented evidence that the correct generic name was Phrynohyas. The problem originated with Fitzinger's (1843, p. 30) cryptic generic as- signments : "Phrynohyas Cephalophractus Fitz. — Cephalo. galeatus Fitz. Trachycephahis Tschud. — Trachy. nigromaculatus Tschud. Phrynohyas— Hyla zonata Spix Acrodijtes — Hyla venulosa Daudin" As discussed by Duellman (1956a, p. 7), Cephalophractus and C. galeatus are nomina nuda. Trachycephahis is a valid genus con- taining three species (Trueb, 1970a, 1970b). Duellman (1956a, p. 7) argued that Acro- dijtes and Hyla venulosa were nomina dubita: "It is evident from the examination of Fitz- inger's work that the person's name following each specific name is usually the authority for the current generic and specific word combi- nation, rather than the original describer of the species. Thus, since Daudin first used the combination Hyla venulosa, his name appears after the specific name instead of that of the original describer of venulosa, namely Lau- renti. Although Daudin, both in 1802 when he referred venulosa to the genus Rana and in 1803 when he referred it to Hyla, described and figured (1802) a hylid frog with paired lateral vocal sacs behind the angles of the jaws, he considered the specific name as that of Laurenti ( 1768 ) . Laurenti based his de- scription on a plate in Seba (1734, 1: 115, pi. 72, fig. 4). This figure cannot, by any exer- cise of the imagination, conceivably be that of a hylid frog. There are no webs or toe discs; furthermore, there is a dorsolateral fold! Daudin was in error, therefore, when he used Laurenti's name venulosa for a hylid frog with paired lateral vocal sacs. Unfortunately, this error has been perpetuated through the literature for the past 150 years. Since the name Rana venulosa Laurenti cannot be ap- plied to any hylid frog, and since neither the figure nor the description gives any possible clues to the identity of the frog figured by Seba, the name Rana venulosa must be con- sidered a nomcn dubium. It follows that the generic name Acrodijtes (with Rana venulosa Laurenti [=Hyla venulosa Daudin] the type species by monotypy) also must be consid- ered a nomcn dubium. Thus, Phrynohyas (type species Hyla zonata Spix by monotypy) is the correct generic name for those hylid frogs with paired lateral vocal sacs behind the angles of the jaws and without the skin of the head co-ossified with the skull." Duellman (1956b, p. 145) requested that the International Commission on Zoological Nomenclature suppress the generic name Acrodijtes Fitzinger, 1843, and the specific name venulosa Laurenti, 1768, for the pur- poses of the Law of Priority but not for those of the Law of Homonymy, and to place Phrynohyas Fitzinger, 1843 (type species, by monotypy: Hyla zonata Spix, 1824) on the Official List of Generic Names in Zoology. Skillful legal manipulation by the commission resulted in Acrodijtes being suppressed and Phrynohyas being placed on the Official List of Generic Names in Zoology with "Rana venulosa Laurenti, 1768 ( =Hyla zonata Spix, 1824)" as the type species (see Hemming, 1958). This action served to conserve the well-known specific name venulosa. Duellman (1956a, p. 8) considered Hyla tihiatrix Laurenti, 1768, a name usually placed in the synonymy of venulosa, to be a nomen dubium and (1956b, p. 145) requested the suppression of the specific name, a request that was acted upon favorably by the Inter- national Commission on Zoological Nomen- clature (Opinion No. 520) (Hemming, 1958). Rivero ( 1961 ) was unaware of this opinion when he suggested that Duellman's treatment of venulosa as a nomen dubium be followed but that Hyla tihiatrix be used instead of Phrynohyas zonata. 162 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Thus, after all of these decades of confu- sion, the ruling by the International Commis- sion on Zoological Nomenclature (Opinion No. 520) should result in nomenclatural sta- bility with Rana venulosa Laurenti, 1768, as the type species of Phrynohyas Fitzinger, 1843. Etymology: The generic name is derived from the Greek phrynos, meaning toad, and Hijlas, a character in Greek mythology. The generic name literally means a toad-tree frog. Definition: The frogs in this genus are large pond-breeding species; males attain snout-vent lengths of 100 mm. and females, 114 mm. The dorsum is tan or brown usually with a darker blotch or two on the back and transverse marks on the limbs. The fingers are about one-third and the toes about two- thirds webbed. Dermal appendages and an axillary membrane are absent. The palpebral membrane is clear. The skin on the dorsum is thick, glandular, and pustulate; there is no integumentary-cranial co-ossification. Males have paired lateral vocal sacs behind the an- gles of the jaws and horny nuptial excres- censes on the prepollices. The skull is broad and well ossified; there is no frontoparietal fontanelle ( fig. 63 ) . The maxillaries and pre- maxillaries are robust. The nasals are large, in broad contact medially, and broadly su- tured with the sphenethmoid, which is well ossified. The squamosal is in bony contact with the crista parotica, and the anterior arm of the squamosals is in bony contact with the crista parotica; the anterior arm of the squamosal extends about half of the distance to the maxillary. A quadratojugal is present and articulates with the maxillary. The pre- vomers are large; their dentigerous processes are massive and curved. The medial ramus of the pterygoid is in bony contact with the prootic. Bifid, spatulate teeth are present on the maxillaries, premaxillaries, and prevomers. The tadpoles have deep caudal fins, a median anal tube and anteroventral mouths with four upper and six lower rows of teeth. The mating call consists of a loud series of growls. The haploid number of chromosomes is 12. Composition of the Genus: The number of species in this genus is unknown at this time. The only Middle American species, P. venulosa, is widespread in South America; perhaps P. hebes (Cope) is conspecific with venulosa. Other South American species in- clude P. mesophaea (Hensel) and P. imita- trix (Miranda-Ribeiro) in eastern Brazil, P. ingens Duellman in the Maracaibo Basin, P. macrotis in Amazonian Ecuador, and P. coriacea (Peters) in the Amazon Basin and Guianas. I have examined 775 preserved frogs, seven skeletons, and four lots of tad- poles of P. venulosa from Middle America. Distribution: The genus occurs through- out subhumid lowlands from central Tamauli- pas and southern Sinaloa, Mexico, southward through Middle America (Pacific lowlands only in lower Central America) to South America, where it is widespread east of the Andes southward to northern Argentina. Fig. 63. Dorsal (A) and ventral (B) views of the skull of Phrynohyas venulosa, K.U. No. 68175. X 3. 1970 DUELLMAN: HYLID FROGS 163 Discussion: The greatest amount of dif- ferentiation in Phrynohyas is in South Amer- ica. Duellman ( 1956a ) recognized five spe- cies in Middle America, but these are cur- rently considered to be nothing more than variants of the widespread Phrynohyas venu- losa (Duellman, 1966b, and McDiarmid, 1968). Two of the currently recognized species in South America apparently are closely re- lated to P. venulosa. One of these, P. hebes of Paraguay, northern Argentina, and south- ern Minas Gerias, Brasil, possibly is conspe- cific with venulosa, whereas the other, P. in- gens, occurs sympatrically with venulosa in the Maraeaibo Basin of Venezuela and Co- lombia (Cochran and Goin, 1970). Phryno- lnjas imitatrix and mesophaea are much smaller than venulosa and occur in south- eastern Brasil. Phrynohyas coriacea is known from the Guianas and the upper Amazon Basin; it also is smaller and more brightly colored than venulosa (Duellman, 1968c). Only four currently recognized genera of hylids have paired lateral vocal sacs behind the angles of the jaws. There are Phrynohyas, Argenteohyla, Osteocephalus, and Trachy- cephalus. The last genus is characterized by extensive integumentary-cranial co-ossifica- tion and the development of a cranial casque. Trueb (1970a) noted that the differences be- tween the skulls of Osteocephalus and Trach- ycephalus are principally the result of a marked evolutionary trend toward increased dermal ossification from the former to the latter. Furthermore, she suggested that on the basis of cranial morphology, Phrynohyas "represents a logical choice for the modern descendent of a progenitor which gave rise to a single phyletic line of casque-headed frogs beginning with Osteocephalus and ter- minating with Trachycephalus jordani." Phrynohyas venulosa Laurenti Rana venulosa Laurenti, 1768, p. 31 [based on a plate in Seba ( 1734, vol. 1, pi. 72, fig. 4)]. Hyla venulosa: Daudin, 1803, p. 71. Boulenger, 1882a, p. 364. Gunther, 1901 (1885-1902), p. 272. Kellogg, 1932, p. 154. Hyla zonata Spix, 1824, p. 41 [type unknown; from Lago Teffe at mouth of Rio Teffe, Amazonas, Brasil; collector unknown]. Hyla bufonia Spix, 1824, p. 42 [type unknown; from Eca, Amazonas, Brasil; collector unknown]. Hyla vermiculata Dumeril and Bibron, 1841, p. 563 [holotype, M. N.H.N. No. 4797 from "Amerique"; presented by Mr. Harlan]. Phrynohyas zonata: Fitzinger, 1843, p. 30. Duell- man, 1956a, p. 35. Acrodytes venulosa: Fitzinger, 1843, p. 30. Tay- lor, 1944b, p. 64; 1952c. p. 800. Hyla lichenosa Gunther, 1859 [lectotype, B.M.N.H. No. 1936.12.3.119 from Amazonas, Brasil; collector unknown]. Brocchi, 1882, p. 33. Boulenger, 1882a, p. 364. Scytopis venulosus: Cope, 1866b, p. 85. Hyla spilomma Cope, 1877, p. 86 [holotype, ap- parently lost, from Cosamaloapam, Veracruz, Mexico; Francis Sumichrast collector]. Brocchi, 1881, p. 39. Gunther, 1901 ( 1885-1902 ), p. 282. Hyla paenulata Brocchi, 1879, p. 21 [holotype, formerly in M.N.H.N., now lost, from western (south- ern) Guatemala; collector unknown]; 1882, p. 45. Hyla nigropunctata Boulenger, 1882a, p. 366 [syn- types, B.M.N.H. Nos. 59.9.20.2 and 81.10.31.20 from Jalapa, Veracruz, Mexico; Mr. Hoege collector], Hyla resinifictrix Goeldi, 1907, p. 135 [holotype, B.M.N.H. No. 1947.2.23.24 from San Antonio do Prata, Para, Brasil; Emil Goeldi collector]. Acrodytes inflata Taylor, 1944b, p. 63 [holotype, F.M.N.H. No. 100046 (formerly E.H.T.-H.M.S. No. 17890) from La Venta, Guerrero, Mexico; Edward H. Taylor collector]. Smith and Taylor, 1948, p. 74. Acrodytes spilomma: Taylor, 1944b, p. 64. Smith and Taylor, 1948, p. 75. Acrodytes modesta Taylor and Smith, 1945, p. 594 [holotype, U.S.N.M. No. 115013 from Cruz de Piedra, near Acacoyagua, Chiapas, Mexico; Hobart M. Smith collector]. Smith and Taylor, 1948, p. 74. Phrynohyas inflata: Duellman, 1956a, p. 19. Phrynohyas latifasciata Duellman, 1956a, p. 24 [holotype, B.M.N.H. No. 83.2.7.1 from Presidio, Sina- loa, Mexico; Alphonso Forrer collector]. Plirynoliyas modesta: Duellman, 1956a, p. 25, Stuart, 1963, p. 37. Phrynohyas spilomma: Duellman, 1956a, p. 28. Stuart, 1963, p. 37. Plirynohyas corasterias Shannon and Humphrey, 1957, p. 15 [holotype, U.I.M.N.H. 67060 (formerly F.A.S. No. 11307) from 4.8 miles east of San Bias, Nayarit, Mexico; Frances L. Humphrey and Frederick A. Shannon collectors]. Phrynohyas venulosa: Hemming, 1958, p. 172. McDiarmid, 1968, p. 2. Hyla tibiatrix tibiatrix: Rivero, 1961, p. 127. Hyla venulosa venulosa: Rivero, 1964, p. 311. Diagnosis: This large tree frog has thick glandular skin on the dorsum and heavily granular skin on the venter. Most individuals 164 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 have a dark dorsal blotch, which is continuous from the occiput to the posterior end of the bodv, transversely interrupted in the sacral region, or medially divided anteriorly. Dis- tinct transverse bands are present on the limbs. Some individuals are unicolor brown above. Phrynohyas vemriosa differs from all other Middle American hylids by having paired lateral vocal sacs behind the angles of the jaws and by having thick glandular skin on the dorsum. Phrynohyas lacks the vertical bars on the lips and cream and black mottling on the flanks characteristic of Smilisca batt- el inii, the only other Middle American species easily confused with Phrynohyas. Description: Males of this large species attain a maximum known snout-vent length of 100.5 mm., and females reach 113.7 mm. In a series of 23 males from 4 kilometers west- northwest of Esparta, Puntarenas Province, Costa Rica, the snout-vent length is 79.9 to 95.6 (mean, 88.6) mm.; the ratio of tibia length to snout-vent length is 0.436 to 0.484 (mean, 0.461); the ratio of foot length to snout-vent length is 0.374 to 0.419 (mean, 0.394); the ratio of head length to snout-vent length is 0.264 to 0.299 (mean, 0.284); the ratio of head width to snout-vent length is 0.306 to 0.346 (mean, 0.330), and the ratio of the diameter of the tympanum to that of the eye is 0.539 to 0.794 (mean, 0.682). Four females from the same locality have snout- vent lengths of 92.6 to 105.9 (mean, 98.1) mm. They differ from the males by having slightly larger tympani; the ratio of the diameter of the tympanum to that of the eye is 0.635 to 0.766 (mean, 0.715). McDiarmid (1968) in a careful analysis of variation in this species in Middle America, showed that the largest individuals are found in northwestern Mexico and in southern Costa Rica and Panama. My data, based in a large part on the examina- tion of the same specimens as studied by McDiarmid, support these conclusions. Four- teen males from 10 kilometers west-southwest of Chepo, Panama Province, Panama, have snout-vent lengths of 77.8 to 99.8 (mean, 88.0) mm., and three females from the same locality have snout-vent lengths of 97.8 to 106.4 (mean, 102.8) mm. The largest specimens from Middle America are from Palmar, Pun- tarenas Province, Costa Rica; five males have snout-vent lengths of 92.7 to 100.5 (mean, 95.8) mm., and three females have snout-vent lengths of 96.6 to 113.7 (mean, 104.4) mm. (table 14). Although there is considerable variation in proportions in series of specimens from throughout the range of this species in Middle America, there are no statistically sig- nificant differences. The head is somewhat narrower than the body, which is robust; the top of the head is flat. In dorsal profile, the snout is bluntly rounded; in lateral profile it is bluntly round or nearly truncate. The snout is moderately short; the nostrils are noticeably protuberant at a point about four-fifths of the distance from the eyes to the tip of the snout. The internarial region is slightly depressed. The canthus is rounded, but distinct; the loreal region is barely concave and the lips are moderately thin and flared. A heavy dermal fold extends posteriorly from the eye, above the tympanum, to a point above the insertion of the arm. In some specimens, the fold is excessively heavy and nearly completely ob- scures the tympanum. In others, only the upper edge of the tympanum is obscured; otherwise, the tympanum is distinct and sepa- rated from the eye by a distance equal to the diameter of the tympanum. The arms are short and robust; an axillary membrane is absent. No distinct row of tu- bercles is present on the ventrolateral edge of the forearm, but a heavy dermal fold is pres- ent on the wrist. The fingers are short and robust and bear large discs; the width of the disc on the third finger is greater than the diameter of the tympanum. The subarticular tubercles are large and round; the distal tu- bercles on the fourth finger is bifid in most specimens. The supernumerary tubercles are small and indistinct. No distinct palmar tu- bercle is evident. The prepollex is moderately enlarged and in breeding males bears a smooth, horny nuptial excrescence. The fin- gers are about one-half webbed (fig. 64A). The webbing is vestigial between the first and second fingers and extends from the mid- dle of the penultimate phalanx of the second to the middle of the antepenultimate phalanx of the third, and from the distal end of the antepenultimate phalanx of the third to the base of the penultimate phalanx of the fourth 1970 DUELLMAN: HYLID FROGS 165 TABLE 14 Geographic Variation in Snout-vent Length, With Means in Parentheses, of Phrijnohyas venulosa. Locality Sinaloa, Mexico" Nayarit, Mexico ~. Colima-Guerrero, Mexico Tamaulipas, Mexico San Luis Potosi, Mexico . Veracruz, Mexico Yucatan Peninsula El Peten, Guatemala Pacific Chiapas Pacific Guatemala Esparta, Costa Rica Palmar, Costa Rica Chepo, Panama N Males Size N Females Size 6 74.2-90.2 (80.9) 1 89.0 15 79.8-91.2 (85.3) 1 97.3 5 63.5-92.0 (80.3) 0 2 72.0-80.0 3 74.0-77.0 (76.0) (75.0) 4 74.0-86.0 7 63.0-84.0 (81.0) (69.4) 68 57.0-78.0 60 56.0-77.0 (66.4) (66.1) 10 73.0-87.0 4 71.0-92.5 (78.4) (81.4) 21 60.0-82.0 9 73.0-82.0 (72.7) (76.7) 13 54.0-69.5 14 52.0-80.5 (63.7) (63.5) 52 55.1-72.3 20 61.1-80.2 (64.1) (65.2) 23 79.9-95.6 4 92.6-105.9 (88.6) (98.1) 5 92.7-100.5 3 96.6-113.7 (95.8) (104.4) 14 77.8-99.8 3 97.8-106.4 (88.0) (102.8) " Data from McDiarmid (1968.) finger. The legs are short and robust. In adults, the heels of the adpressed limbs over- lap by about one-sixth of the length of the shank; the tibiotarsal articulation extends to the point of insertion of the arm. A heavy transverse dermal fold is present on the heel, and a distinct, curved, tarsal fold is present. The inner metatarsal tubercle is large and ovoid; a small conical outer metatarsal tu- bercle is present. The toes are moderately short and bear discs that are noticeably smaller than those on the fingers. The sub- articular tubercles are moderately large and subconical; the supernumerary tubercles are small and numerous on the proximal segments of each digit. The toes are about three-fourths webbed (fig. 64B). The webbing extends from the base of the disc of the first toe to the base of the penultimate phalanx of the second, from the base of the disc of the second to the distal end of the antepenulti- mate phalanx of the third, from the base of the disc of the third to the base of the pen- ultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly near the upper level of the thighs; a short anal sheath is present. The skin on the dor- sum is smooth or weakly tuberculate in adults and heavily tuberculate in small individuals. The skin on the throat, belly, and postero- ventral surfaces of the thighs is heavily granu- lar, and that on the other ventral surfaces is smooth. The tongue is broadly cordiform, deeply notched posteriorly, and barely free behind. The dentigerous processes of the 166 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 64. Hand (A) and foot (B) of Phrynohyas oenulosa, K.U. No. 108867. x 2.5. prevomers are slightly curved, transverse, nar- rowly separated elevations between the pos- terior margins of the moderately large ellip- tical choanae. Males have five to 12 teeth on each process and a total of 10 to 24 ( mean, 15.7) prevomerine teeth; females have five to 14 teeth on each process and a total of 10 to 27 (mean, 17.2) prevomerine teeth. The vocal slits are short and extend posterolaterally from the midlateral base of the tongue. The vocal sacs are paired and located behind the angles of the jaws; the sacs are greatly distensible. The general coloration of Phrynohyas oenu- losa is tan, reddish brown, or pale gray with a large darker mark on the dorsum and trans- verse bands on the limbs (pi. 46). In speci- mens from the vicinity of Esparta, Puntarenas Province, Costa Rica, the dorsum varies from yellowish tan with olive-tan markings to red- dish brown with dark brown markings. The venter is a dirty white. Individuals from Pal- mar, Puntarenas Province, Costa Rica, were reddish brown with dark brown dorsal mark- ings and a creamy yellow venter at night. By day they were tan to yellowish tan with dark brown or olive-brown markings. Sixteen in- dividuals from the vicinity of Chepo, Panama Province, Panama, all were tan with brown markings and a creamy white venter. One individual from Barranca Bejueo, Miehoacan, Mexico, was pale gray with darker greenish gray markings. Three individuals from 3.5 kilometers south of Villahermosa, Tabasco, Mexico, were pale grayish white above and below at night; by day the dorsum changed to uniform gray brown. In all individuals, the iris is a deep golden bronze heavily flecked with black. The deflated vocal sacs are dark brown to black; when the sacs are inflated they are pale brown or olive-brown. Throughout most of the range of the spe- cies in Middle America, the dorsum is marked 1970 DUELLMAN: HYLID FROGS 167 bv a single large dark blotch. In most speci- mens from the southern part of the range (Costa Rica and Panama) the dorsal blotch is distinctly narrower anteriorly than posteri- orly (pi. 46, fig. 4). In southern Mexico (Veracruz and Campeehe) and Guatemala the dorsal blotch usually is nearly as wide anteriorly as it is posteriorly; however, in many individuals the blotch is interrupted by a medial area of ground color anteriorly (pi. 46, fig. 2). On the Pacific coast of Mexico from Sinaloa to Guerrero many individuals have the dorsal blotch interrupted by a trans- verse band of ground color in the sacral region ( pi. 46, fig. 1 ) . In various parts of the range, unicolor individuals are known; these have been reported from British Honduras, Tabasco, Chiapas, Guatemala, Honduras, El Salvador, and northern Costa Rica. In these individuals, dorsal markings are absent, ex- cept that in some of the smaller specimens the warts on the dorsum are tipped with darker pigment (pi. 46, fig. 3). The geo- graphic variation in color pattern in this spe- cies has been thoroughly analyzed by Mc- Diarmid (1968). There is a noticeable ontogenetic change in coloration in this species. Zweifel ( 1964, p. 205) noted that there is a longitudinal dark stripe on the hind legs of the tadpoles. He stated: "The characteristic pattern of the adult frog is not assumed until several days after metamorphosis appears complete. The dark longitudinal stripe so evident on the hind leg of the large tadpole persists in the newly transformed frog and the variable dark figure on the back is slow to appear, so that for a few days the young frog, with unicolor back and striped legs, looks quite unlike the boldly- patterned adult." McDiarmid (1968, p. 16) noted that by the time the frogs reached 24 mm. in snout-vent length, they had attained the adult color pattern. Tadpoles : Zweifel ( 1964 ) described the tadpoles of this species from 5 kilometers south of Bejueo, Panama Province, Panama, and Pyburn ( 1967 ) described the tadpoles under the name of Phrynohyas spilomma from Eneinal, Veracruz, Mexico. I have examined the tadpoles from both of these series plus a small series of tadpoles from 34 kilometers north-northwest of Tepic, Nayarit, Mexico. A typical tadpole in developmental stage 38 from Eneinal, Veracruz, Mexico, has a body length of 13.5 mm. and a total length of 41.0 mm. The body is robust and only slightly deeper than wide. In dorsal profile, the snout is bluntly rounded, and in lateral profile, it is round. The eyes are moderately large, widely separated, and directed laterally. The nostrils are directed anterolateral]}' at a point about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posterodorsally somewhat below the midline at a point about two-thirds of the distance from the snout to the posterior end of the body. The anal tube is short and me- dian. The caudal musculature is moderately slender and tapers to a fine tip nearly to the terminus of the pointed tail. The ventral fin is somewhat deeper than the dorsal one, which extends onto the body. At midlength of the tail, the depth of the dorsal fin is some- what greater than the depth of the caudal musculature (fig. 65). The mouth is medium-sized and antero- ventral in its position. Deep lateral folds are present. The median part of the upper lip is bare; elsewhere, the lips are bordered by two rows of small papillae. Additional rows are present in the lateral folds. The beaks are slender and bear fine serrations. The up- per beak is broadly U-shaped with moderately slender lateral processes. The lower beak is broadly V-shaped. In tadpoles of later stages of development, there are four upper and six Fig. 65. Tadpole of Phrynohyas vemdosa, K.U. No. 116931. X 3. 168 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 lower rows of teeth. The first and second upper rows are present only laterally and in most specimens are fragmented. The third upper row is complete, but the first upper row is narrowly interrupted medially. The first four lower rows are equal in length and somewhat shorter than the third and fourth upper rows. In some specimens, the first lower row is narrowly interrupted medially. The fifth and sixth lower rows usually are fragmented (fig. 66). In life, specimens from Nayarit were dark olive-brown above; the tail was creamy yel- low with a dark brown lateral stripe. The belly was white and the fins were transparent with faint brown flecks. The iris was pale bronze. In preservative, the body is tan with scattered dark brown flecks in larger indi- viduals. The venter is pale creamy tan with scattered brown blotches. The tail is pale cream with a dark brown lateral streak. The fins are transparent with minute flecks. A dark brown stripe is present on the outer edge of the hind limb. Pyburn (1967, p. 189) commented on the development of the teeth: "In general, the tooth rows nearest the beaks appear before those farthest from the beaks, but there is some variation in the time and sequence in appearance of the rows. Teeth are not ap- parent in specimens earlier than stage 24. The third and fourth upper and the first and second lower tooth rows are present in stage 25, and the third lower row is usually added later in that stage. The fourth lower row ap- pears in stage 27; the second upper and fifth ^f^gi^to^" Fig. 66. Mouth of tadpole of Phrynohyas venulosa, K.U. No. 116931. x 15. lower rows usually develop in stage 28. Speci- mens in stage 28 have complete beaks, a tooth row formula of 3/5, and little or no indication of tooth resorbtion. The sixth lower row appears at about stage 31, the first upper row about stage 33, but specimens in stage 33 have 3/5, 3/6, 4/5, or 4/6 rows. After stage 34, the formula is most often 4/6, although the first upper and sixth lower rows may be poorly formed. A few individuals develop a frag- mentary lower seventh row, in which case the formula is 4/7." Zweifel (1964, p. 204) noted that hatch- ing occurs early in stage 18, but Pyburn ( 1967, p. 190) stated that in Veracruz hatching oc- curred in stage 17, 24 hours after fertilization. According to Pyburn the length of the tail is less than that of the body in tadpoles in stages earlier than stage 22. From that point in de- velopment, the tail becomes progressively longer, until in late stages it is approximately twice the length of the body (table 15). Pyburn (1967, p. 193) commented that ad- vanced "P. spilomma" larvae differ from ad- vanced P. venulosa larvae in certain features of the mouthparts and in dorsal pattern. He was particularly concerned that the mouth- parts of the tadpoles from Veracruz were not fully developed until about stage 33 or later whereas according to Zweifel's ( 1964 ) de- scription of Panamanian tadpoles, the mouth- parts obtained full development by stage 27 or 28. Furthermore, Pyburn noted that there were more labial papillae in the specimens from Veracruz than in those from Panama. It is possible that the degree of development of mouthparts in different stages in the two series could be the result of development at different temperatures, or possibly some other environmental factor. A direct comparison of some of the tadpoles in Pyburn's sample with those described by Zweifel, leave no doubt but that the tadpoles are identical. Mating Call: The call of Phrynohyas venulosa consists of a loud growl or raucous note regularly repeated at short intervals. An analysis of the recordings of seven individuals from Panama and Costa Rica show that there is a note repetition rate of 42 to 52 (mean, 47) notes per minute. The duration of each note varies from 0.23 to 0.36 (mean, 0.30) of a second. The notes have 150 to 175 (mean, 1970 DUELLMAN: HYLID FROGS 169 TABLE 15 Measurements of Tadpoles of Phrynohyas venulosa, with Means in Parentheses, from Eneinal, Veracruz, Mexico." Stage N Body Length Tail Length Total Length 17 5 18 4 19 _ 3 20 15 22 .__.. 4 23 10 24 6 25 2 26 10 27 10 28 _ 10 31 _ 10 32 4 33 6 34 3 35 5 36 7 37 4 38 4 40 _ __ 1 41 4 46 1 3.6- 4.1 (3.S) 3.5- 5.4 (3.9) 3.8- 3.8 (3.8) 1.7- 1.7 (1.7) 5.5- 5.5 (5.5) 3.4- 3.8 (3.6) 2.1- 2.7 (2.4) 5.7- 6.1 (6.0) 3.0- 3.2 (3.0) 3.9- 4.1 (4.0) 6.8- 7.2 (7.0) 2.9- 3.4 (3.2) 5.2- 6.2 (5.9) 8.1- 9.6 (9.1) 3.3- 3.7 (3.5) 5.5- 6.8 (6.2) 8.8-10.5 (9.7) 3.7- 3.8 (3.7) 6.5- 6.5 (6.5) 10.2-10.3 (10.2) 4.1- 4.7 (4.6) 7.6- 8.4 (7.9) 11.6-13.5 (12.5) 4.7- 5.6 (5.2) 8.3- 9.5 (8.9) 13.0-15.0 (14.1) 6.0- 8.8 (7.1) 10.3-15.0 (12.2) 16.3-23.8 (19.3) 8.5-10.5 (9.5) 16.3-18.4 (17.4) 24.8-28.3 (26.9) 10.5-11.8 (11.0) 18.8-20.6 (19.5) 29.5-32.4 (30.5) 10.0-11.9 (10.7) 18.8-23.1 (20.4) 29.3-34.4 (30,5) 10.4-11.8 (11.3) 19.5-22.5 (21.4) 29.9-34.3 (32.7) 10.6-13.1 (11.8) 19.5-24.0 (22.2) 30.9-37.1 (34.0) 11.6-13.0 (12.4) 22.8-25.1 (24.2) 34.8-37.9 (36.6) 12.0-12.9 (12.6) 25.0-25.9 (25.3) 37.0-38.1 (37.9) 12.5-13.5 (13.1) 24.9-26.8 (25.8) 37.9-40.1 (38.9) 13.1 25.8 38.9 14.0-15.1 (14.5) 27.7-32.6 (29.6) 41.9-47.8 (44.1) 15.6 Data from Pyburn (1967). 161) pulses per second. The notes are well modulated with distinct harmonics; the funda- mental frequency varies from 139 to 183 (mean, 159) cycles per second, and the domi- nant frequency varies from 1392 to 1946 (mean, 1622) cycles per second. In two indi- viduals it is the eighth harmonic that is domi- nant; in two others the tenth is dominant, and in two others the twelfth is dominant, whereas in another the fourteenth is the dominant harmonic (pi. 36, fig. 3). Zweifel (1964, p. 202) described the mat- ing call of this species on the basis of a re- cording of an individual from Neuva Gorgona, Panama Province, Panama. The call described by Zweifel is virtually the same as those de- scribed here, except that he noted that each note was approximately 0.4 of a second in length and that notes were repeated at about 67 notes per minute. I agree with Zweifel (1964, p. 203) that the description and audio- spectrogram of the call of this species given by Porter (1962, p. 170) is erroneous. Ap- parently a malfunction in the equipment or an inversion of the audiospectrogram resulted in Porter stating that the dominant frequency of this species is between 6000 and 7000 cycles per second. Natural History: Phrynohyas venulosa is widespread throughout the tropical low- lands of Middle America, where it inhabits areas having a noticeably dry season. It is noticeably absent from the wet Caribbean coastal lowlands from southeastern Nicaragua into Panama; however, it does occur in the humid Golfo Dulce region. In the dry season, individuals of this species have been found in bromeliads, tree-holes, under the bark of standing trees, and perhaps most frequently beneath the outer sheaths of banana plants. During the dry season, I have observed indi- viduals that are active at night. Apparently the frogs leave their hiding places at dusk to perch on branches or banana plants, where 170 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 probably they are engaged in active feeding. On the night of March 29, 1959, at Ciudad Aleman, Veracruz, Mexico, a light rain fell for approximately 15 minutes. Shortly after the rain began one and then somewhat later a second Phrynohijas venalosa called inter- mittently. Phrynohyas is an opportunistic breeder; apparently heavy rains are necessary to insti- gate breeding in this species. I have encoun- tered choruses at Amatitlan, Veracruz, Mexico, on July 26, 1956, at Esparta, Costa Rica, on June 21, 1961 (pi. 10, fig. 2), at Palmar, Costa Rica, on April 8, 1966, and near Chepo, Panama, on June 5, 1966. In each case, the chorus was found immediately after a heavy rain. Zweifel ( 1964 ) found calling males near Bejuco, Panama, on June 4, 1962; Pyburn (1967) encountered choruses at Encinal, Veracruz, Mexico, on June 30, 1964, and June 26, 1966. Porter (1962) reported males calling at Cuautlapam, Veracruz, Mexico, on July 1, 1960, and McDiarmid (1968) obtained calling males from 14.4 kilometers south of Escui- napa, Sinaloa, Mexico, on August 3, 1962. Each of these authors noted that calling males were found only after heavy rains. Breeding takes place in shallow, tempo- rary ponds. Usually males call while floating on the water or sitting in shallow water; some individuals were observed to cling with their hands to debris floating in the water. Calling sometimes is initiated prior to the arrival of the males at the pond. On June 5, 1966, at a small rainpool 10 kilometers west-southwest of Chepo, Panama Province, Panama, I ob- served several males calling from branches of trees surrounding the pond; later in the evening most individuals were in the water. The calls are produced by inflating the body; then the body is deflated and the air is pushed into the large globular vocal sacs, which re- semble balloons on either side of the head. In some individuals, the vocal sacs were observed to touch one another above the head. The call is produced at the time of the in- flation of the vocal sacs. At Palmar, Punta- renas Province, Costa Rica, on the night of April 8, 1966, five males were found calling in a shallow temporary pool. In this small chorus there was evidence of social organiza- tion in the call structure. One male seemed to be dominant; it was calling at a distance about 5 meters from the other males. The dominant individual initiated five successive choruses; there was an interval of one to three minutes between choruses. The dominant in- dividual initiated the choruses with a series of notes before the other individuals joined in. Amplexus is axillary and takes place in shallow water. Pyburn (1967, p. 186) de- scribed oviposition at Encinal, Veracruz, Mex- ico: "The female [of an amplectant pair] sud- denly plunged her head below the surface, at the same time extending the hind limbs downward, so that her vent rose about 1 cm. above the water. Her body axis made an angle of approximately 45° with the surface. The male adhered closely to the female's back in axillary amplexus, and eggs were passed while the pair held this tilted position for some five seconds. As the eggs emerged, the female moved her posterior end in rapid side- to-side vibration, possibly to stimulate sperm release by the male. The eggs appeared as an elongate mass, which fell on the water and spread over the surface as a film. After the film had formed, the eggs were about 1 cm. apart in a single layer. The frogs returned to a horizontal position immediately after the egg mass was produced, remained motionless about two minutes, then swam away from the eggs and repeated the performance. I watched another pair deposit eggs in the same manner, captured both pair, and col- lected an egg sample." Pyburn also noted that when he accidentally struck some freshly laid eggs, the eggs sank, whereas when he struck older eggs with about the same force they remained afloat. Zweifel (1964, p. 203) described the surface film eggs of this species from Panama and noted that there was a distance of about 1.5 cm. between the eggs and that the single clutch that he observed covered an area of about 1.5 square meters. Zweifel (1968, p. 206) noted that the surface film type of egg mass apparently is an adap- tation to relatively low oxygen tension present in warm, standing water characteristic at that breeding site of this species. Both Zweifel and Pyburn noted the large external gills in early developmental stages. The young tadpoles were observed to hang vertically with their gills spread out over the 1970 DUELLMAN: HYLID FROGS 171 surface of the water, an apparent adaptation for survival where dissolved oxygen is in short supply. In Nayarit, Mexico, I obtained ad- vanced larvae stages from a shallow weed- choked pond. Both Zweifel and Pyburn raised their tad- poles from eggs; the former recorded meta- morphosis in 37 days, whereas Pyburn re- corded metamorphosis in 47 days. In each case, the metamorphosing young had snout- vent lengths of 15.0 to 16.0 mm. McDiarmid (1968, p. 14) noted recently metamorphosed individuals from Parrita and from Rincon de Osa, Costa Rica, having snout-vent lengths between 13 and 17 mm. Duellman (1956a, p. 14) described the thick dermal glands on the back of Phryno- lujas and noted that the center of glandular development is in the occipital region, but that the glands are extensive over the dorsum. He stated that the skin showed a thickened, glandular condition on the head between the orbits, in the occipital region, and in the supratympanic region; the glandular develop- ment continues posteriorly on the dorsum for a short distance. Duellman further com- mented that sections of the skin show that there is a great development of the granular poison glands. They are much larger and more numerous than the mucous glands. The small pustules on the dorsum show the same kind of glandular development but the skin between the pustules and away from the thickened areas has fewer poison glands and proportionately more numerous mucous glands. McDiarmid (1968, p. 20) noted that in specimens collected in late June and July, during the rainy season, the dermal glands in the neck region show relatively little develop- ment, whereas the glands in specimens col- lected in the dry season, in February or March, show extensive development. He noted that in many specimens obtained in the dry season, the glandular development is so extensive that parts of the tympanum are con- cealed, but that the tympanum is never con- cealed in Costa Rican specimens taken in the rainy season. McDiarmid (1968, p. 21) stated: "All Phnjnohyas venulosa examined have these glands, whether the frogs are from areas with a definite wet-dry season or from areas where there is some precipitation throughout the year. Frogs from the dry forests of Costa Rica, where there is a marked wet-dry season, apparently exhibit a change in the glandular development from season to season. It is sug- gested that the greater development and sub- sequent secretion of the glands in the dry season is produced as an adaptive response to arid environments." This suggestion was first made by Neill and Allen (1959, p. 25); these authors, as well as others (Smith, 1941, p. 38; Duellman, 1956a, p. 41) also suggested that the secretions from these dermal glands probably is an effective deferent to predation. McDiarmid (1968, p. 21) presented a well- documented discussion of slime secretions being a factor in decreasing permeability of the skin to water, a mechanism for the pre- vention of desiccation that is well documented in lung fish. It is interesting to note that Goeldi (1907, p. 135) and Vellard (1948, p. 150) reported that Phnjnohyas produced a cutaneous secretion to line the cavities of trees in which they seek refuge. McDiarmid ( 1968, p. 21) noted that if this is a response to aridity, then this peculiar behavior suggests that Phnjnohyas has developed a modification to decrease water loss which is similar to that mechanism utilized by the lung fish (Smith, 1961, p. 77-78). Remarks: McDiarmid (1968) attempted to explain the geographic variation in size in Phnjnohyas venulosa in Middle America on the basis of a natural selection for large size in drier environments. In the northern part of the range of the species, the larger indi- viduals are found in dry environments, such as Sinaloa, San Luis Potosi, and Yucatan (com- pare the sizes of individuals from these areas with those from Veracruz, Mexico, and El Peten, Guatemala, in table 14). The explana- tion given by McDiarmid is entirely reason- able; however, the largest known specimen of Phnjnohyas venulosa from anywhere in the range of the species is from Palmar in the wet Golfo Dulce region in southern Costa Rica. This area not only has a high annual rainfall but has rain well distributed throughout the year. An interesting corollary is the gigantic size attained in the Golfo Dulce region as compared with other parts of the range in Smilisca phaeota. Perhaps some degree of isolation in population in this area is responsi- 172 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 0 200500 ' kilometer!^ 105° 99° 93° 87° Fig. 67. Distribution of Phrynohyas venulosa in Middle America. ble for differences in size that have resulted through natural selection aside from the gen- eral trend towards larger size in drier environ- ments. Duellman ( 1956a ) recognized four species in Middle America, but later (1966b) showed that one of these (P. modesta) was a color variant of spilomma. Recently collected ma- terial, much of which was analyzed by Mc- Diarmid ( 1968 ) , confirms the suspicions of the skeptics of Duellman's ( 1956a ) arrange- ment; all Middle American specimens appar- ently belong to one highly variable species. The reader is referred to McDiarmid's (1968) detailed discussion of variation. The venomous properties of the skin secre- tions of Phrynohyas venulosa are well known and have been documented by Duellman' (1956a), Shannon and Humphrey (1957), Neill and Allen (1959), and Janzen (1962). The volatile alkaline secretion is insoluble in water and has a deliterious effect on mucous membranes of the eyes and nostrils. Etymology: The specific name is derived from the Latin, venula, meaning small veins and the Latin osus, meaning full of, and ap- parently refers either to the secretory prop- erties of the skin or to the areolate or venated pattern on the flanks. Distribution: Phrynohyas venulosa is widespread throughout the lowlands of Mid- dle America from central Tamaulipas and southern Sinaloa, Mexico, southward on both coasts to central Nicaragua and thence only on the Pacific lowlands through Panama (fig. 67 ) . This species generally occurs at eleva- tions below 1000 meters and is absent from the wet forests on the Caribbean lowlands of southern Nicaragua to central Panama. In South America, this species is widespread in the lowlands east of the Andes. See Appendix 1 for the locality records of the 786 specimens examined. Neill ( 1965 ) and Mertens (1952b) recorded the species from additional localities in British Honduras and El Salvador, respectively. 1970 DUELLMAN: HYLID FROGS 173 Genus Hyla Laurenti6 Hyla Laurenti, 1768, p. 32 [type species, Hyla viri- dis Laurenti, 1768 (=Rana arborea Linnaeus, 1758), by subsequent designation (Stejneger, 1907)]. Calamita Schneider, 1799, p. 151 [type species, Rana arborea Linnaeus, 1758, by subsequent desig- nation (Stejneger, 1907)]. Hylaria Rafinesque, 1814, fasc. 7 [substitute name for Hyla]. Boana Gray, 1825, p. 214 [type species, Rana boans Linnaeus. 1758, by monotypy]. Hylaplesia Boie, 1826, p. 239 [type species, Hyla punctata Daudin, 1803, by subsequent designation (Stejneger, 1937); preoccupied by Hylaplesia Schle- gel, 1826 (—Dendrobates)]. Hypsiboas Wagler, 1830, p. 200 [type species, Hyla palmata Daudin, 1803, by monotypy]. Aulctris Wagler, 1830, p. 201 [type species, Rana boans Linnaeus, 1758, by subsequent designation (Stejneger, 1907)]. Hyas Wagler, 1830, p. 201 [type species, Rana arborea Linnaeus, 1758; preoccupied by Hyas Leach, 1815 (Crustacea)]. Scinax Wagler, 1830, p. 201 [type species, Hyla aurata Wied, 1825, by subsequent designation (Stej- neger, 1907)]. Dcndrohyas Wagler, 1830, p. 342 [substitute name for Hyas Wagler, 1830; preoccupied by Hyas Leach, 1815 (Crustacea)]. Lophopus Tschudi, 1838, p. 32, 73 [type species, Hyla marmorata (Laurenti), 1768, by original desig- nation; preoccupied by Lophopus Dumeril, 1837 (Polyzoa)]. Ranoidea Tschudi, 1838, p. 35 [type species, Hyla jacksoni Bibron (in Tschudi, 1838; nomen nudum) by monotypy]. Litoria Tschudi, 1838, p. 36 [type species, Hyla freycineti Tschudi, 1838, by monotypy]. Hypsipsophus Fitzinger, 1843, p. 30 [type species, Hyla xerophilla Dumeril and Bibron, 1841, by mono- typy]. 0 The most recent synonymy of the genus Hyla (Goin, 1961b) differs from that presented here by the omission of two names (Ololygon Fitzinger, 1843, and Pelobius Fitzinger, 1843), by the exclusion of Hylonomus Peters, 1882a ( =Hyloscirtus Peters, 1882b), and by the inclusion of four names not now considered to be synonyms of Hyla (Phyllodytes Wagler, 1830); Palmatorappia Ahl, 1927; Pseudohyla Andersson, 1945; Limnaoedus Mittleman and List, 1953). Phyllodytes is an older generic name for the frogs formerly placed in the genus Amphodus ( Boker- mann, 1966a). Palmatrorappia is a ranid. The type species of Pseudohyla (nigrogrisea) is an Eleutherodac- tylus (fide John D. Lynch, personal communication). The generic status of Hylodes ocularis Holbrook ( type species of the monotypic genus Limnaoedus) is open to question; Lynch (1966b) and Chan tell (1968) presented osteological data in support of the generic separation from Hyla. Lobipes Fitzinger, 1843, p. 30 [type species, Hyla palmata Daudin, 1803, by monotypy; preoccupied by Lobipes Cuvier, 1817 (Aves)]. Osteopilus Fitzinger, 1843, p. 30 [type species, Trachycephalus marmoratus Bibron, 1842, in Ramon de la Sagre, by monotypy; nee Hyla marmorata Laur- enti), 1768; (=Htjla septentrionalis Dumeril and Bibron)]. Phyllobius Fitzinger, 1843, p. 30 [type species, Hyla albomarginata Spix, 1824, by monotypy; preoc- cupied by Phyllobius Schonherr, 1824 (Coleoptera)]. Dcndropsophus Fitzinger, 1843, p. 31 [type species, Hyla frontalis Daudin, 1803, by monotypy]. Dryophytes Fitzinger, 1843, p. 31 [type species, Hyla versicolor LeConte, 1825, by monotypy]. Ololygon Fitzinger, 1843, p. 31 [type species, Hyla strigilata Spix, 1824, by monotypy]. Pelobius Fitzinger, 1843, p. 31 [type species, Hyla freycineti Tschudi, 1838, by original designation]. Centrotelma Burmeister, 1856, p. 97 [type species Hyla infulata Wied, 1825, by monotypy]. Hylomedusa Burmeister, 1856, p. 102 [type species Hyla crepitans Wied, 1824, by monotypy]. Pelodryas Gimther, 1859, p. 119 [type species, Rana caerulea Shaw, 1802, by monotypy]. Hylella Reinhardt and Lutken, 1862, p. 199 [type species, Hylella tenera Reinhardt and Lutken, 1862, by subsequent designation (Smith and Taylor, 1948)]. Cinclidium Cope, 1867a, p. 200 [type species, Cin- clidium granulatum Cope, 1867a, by monotypy; pre- occupied by Cinclidium Blyth, 1842 (Aves)]. Chirodryas Keferstein, 1867, p. 358 [type species, Chirodryas raniformis Keferstein, 1867, by monotypy ( =Hyla aurea Lesson, 1830)]. Cincloscopus Cope, 1870, p. 554 [substitute name for Cinclidium Cope, 1867a; preoccupied by Cincli- dium Blyth, 1842 (Aves)]. Cophomantis Peters, 1870, p. 650 [type species, Cophomantis punctillata Peters, 1870, by monotypy]. Exerodonta Brocchi, 1879, p. 20 [type species, Exerodonta sumichrasti Brocchi, 1879, by monotypy], Hylonomus Peters, 1882a, p. 107 [type species, Hylonomus bogotensis Peters, 1882a, by monotypy; preoccupied by Hylonomus Dawson, 1860 (Amphib- ia)]. Hyloscirtus Peters, 1882b, p. 127 [substitute name for Hylonomus Peters, 1882a; preoccupied by Hylono- mus Dawson, 1860 (Amphibia)]. Epedaphus Cope, 1885a, p. 383 [type species, Hyla gratiosa LeConte, 1856, by monotypy]. Fanchonia Werner, 1893, p. 82 [type species, Fanchonia elegans Werner, 1893 ( =Hyla aurea Les- son, 1830) by monotypy]. Hyliola Mocquard, 1899b, p. 337 [type species, Hyla regilla Baird and Girard, 1852, by subsequent designation (Stejneger, 1907)]. Guntheria Mirando-Ribeiro, 1926, p. 67 [type spe- cies, Hyla dasynota Giinther, 1869 ( =Hyla senicula Cope, 1868)]. 174 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Generotype: The generic name was pro- posed by Laurenti ( 1768, p. 32 ) , who listed nine species in the genus. Stejneger ( 1907, p. 75) designated Hyla viridis Laurenti as the type species of Hyla. Most workers, beginning with Daudin (1802, p. 14) have considered Hyla viridis Laurenti to be a synonym of Rana arborea Linnaeus, 1758. Thus, the generotype of Hyla is Hyla viridis Laurenti, 1768 ( =Rana arborea Linnaeus, 1758). Etymology: According to Stejneger (1907, p. 75) the generic name is "Not de- rived from the Greek word v\i), a wood-land, copse, as commonly stated, but from the voca- tive of Hylas, in Greek mythology, the favor- ite of Hercules, who lost him in Bithynia, the crying of hyla, hyla being part of the re- ligious ceremonies instituted in his honor. The croaking of the tree-toad suggested to Laurenti the fanciful idea of its being Hyla's priest, and thus meriting his name, 'haec quasi Hylae sacerdos nomen ejusdem merita est.' " Definition: The frogs in this genus range in size from minute, delicate frogs, such as Hyla minuta, nana, and picta, having snout- vent lengths of less than 25 mm. to gigantic species, such as Hyla boans, faber, and vasta, some females of which attain snout-vent lengths of 132 mm. The coloration is as vari- able as size; many small species are nearly uniform yellow, some are green, others are boldly patterned. Bright flash-colors are pres- ent in some species; notable among the Mid- dle American species are the red webs in Hyla loqaax and rufitela. The color of the iris is bronze or copper in most species, but it is bright red in members of the erythromma and itranocltroa groups. The palpebral mem- brane is clear in most species but is reticulated in a few. The pupil is horizontally elliptical. Webbing is absent on the hands in some spe- cies, principally the Hyla eximia group in Middle America; most species have the fingers one-third to one-half webbed, but in some species in the boans and miliaria groups, the fingers are fully webbed. The toes are at least half webbed. An axillary membrane, dermal fringes on the limbs, calcar, and thoracic fold are present in some species. The skin is smooth or tuberculate dorsally and always granular ventrally; in some members of the miliaria and septentrionalis groups the skin on the top of the head is co-ossified with the underlying cranial bones. In most species the prepollex is enlarged and in breeding males bears a horny nuptial excrescence; in others, the excrescence is absent, whereas in mem- bers of the albomarginata, boans, and miliaria groups the prepollex is protruding and in some individuals a projecting prepollical spine is present. A vocal sac is absent in some of the stream-breeding species in the bistincta, mixo- maculata, and taeniopus groups, but a single, median, subgular vocal sac is present in most species. The cranial characters are highly variable; most species have a frontoparietal fontanelle. The quadratojugal is present, reduced, or ab- sent, and the anterior arm of the squamosal does not extend to the maxillary. The medial ramus of the pterygoid is in bony contact with the prootic in some species. Palatines are present in most species ( lost in some members of the rubra group). Teeth are present on the maxillary and premaxillary, and usually on the prevomer. With the exception of integu- mentary-cranial co-ossification in two groups and the presence of a dermal sphenethmoid and posterolateral expansions of the fronto- parietals in the septentrionalis group, striking modifications of dermal cranial elements are lacking. Insofar as is known, all species have aquatic tadpoles. Some of these develop in ponds, others in streams, and a few in brome- liads or water-filled cavities in trees. The diverse development sites are correlated with a wide variety of morphological types of tad- poles. In some the tail is short with deep fins; in others, the caudal musculature is long and the fins are shallow. The mouth varies in posi- tion from anterodorsal, terminal, and antero- ventral to ventral. Tadpoles of some species lack teeth, but most have two upper and three lower rows of teeth. The number of tooth rows is higher in many stream-inhabiting tad- poles; proliferation is greatest in the Brasilian Hyla claresignata, which has nine upper and 14 lower rows. Among Middle American spe- cies, members of the Hyla mixomaculata group have the greatest number of tooth rows — seven above and 11 below. Some stream-breeding species in the bi- stincta, mixomaculata, and taeniopus groups 1970 DUELLMAN: HYLID FROGS 175 lack a voice. Among the vast majority of the Middle American species of Hyla the call is well-developed and varies greatly from group to group. Most Hyla in the Americas, for which counts are available, have a haploid number of 12 chromosomes; members of the predominantly South American leucophyUata, microcephala, and parviceps groups have 15 chromosomes. The same number of chromo- somes is present in the Papuan Hyla angiana, whereas other Australo-Papuan species, for which data are available, have a haploid num- ber of 13, the same as the American phyllo- medusine genera ( Duellman, 1967b ) . Composition of Genus: This immense genus, as now recognized, probably contains more than 300 species. The vast majority of the species occur in South America, and 73 species (five polytypic) are known from Middle America. Four of these are among the 14 occurring in the United States. Of the 73 species from Middle America, I have ex- amined 20,835 preserved frogs, 334 skeletons, 290 lots of tadpoles, and 29 preserved clutches of eggs. Distribution: Hyla is nearly world-wide, except for the Antarctic, Arctic, and subarctic regions, Africa south of the Sahara, the islands in the Pacific Ocean, and the southern tip of South America. Species of Hyla occur throughout Middle America from sea level to elevations in excess of 3000 meters. Discussion: I have arranged the 73 Mid- dle American species into 28 species groups, as follows: 1. rubra group — 24 species, five Middle American (two endemic); a predominately South American group. 2. microcephala group — nine species, four Middle American (two endemic); a predomi- nately South American group. 3. leucophyUata group — 10 species, one Middle American; a predominately South American group. 4. parviceps group — eight species, one in lower Central America; a predominately South American group. 5. albomarginata group — nine species, one in lower Central America; a predominately South American group. 6. boans group — seven species, three in lower Central America; a predominately South American group. 7. pseudopuma group — two species, lower Central American montane pond-breeders. 8. rivularis group — four species, lower Central American stream-breeders. 9. pictipes group — one species, lower Cen- tral American stream-breeder. 10. uranochroa group — two species, lower Central American stream-breeders. 11. lancasteri group — one species, lower Central American stream-breeder. 12. zeteki group— two species, lower Cen- tral American bromeliad-breeder. 13. bogotensis group — probably at least four species, one in Middle America, lower Central American and northwestern South American stream-breeders. 14. salvadorensis group — two species, Central American stream-breeders. 15. miliaria group — five species, Mexican and Central American fringe-limbed tree frogs. 16. godmani group — two species, Mexican and Central American lowland pond-breeders. 17. picta group — two species, Mexican and northern Central American lowland pond- breeders. IS. miotympanum group — two species, Mexican stream-breeders. 19. hazelae group — two species, Mexican stream-breeders. 20. erythromma group — one species, Mexi- can stream-breeder. 21. pinorum group — two species, Mexican stream-breeders. 22. sumichrasti group — two species, Mexi- can stream-breeders. 23. mixomacidata group — four species, Mexican stream-breeders. 24. bromeliacia group — two species, Mexi- can and northern Gentral American brome- liad-breeders. 25. taeniopus group — three species, Mexi- can stream-breeders. 26. bistincta group — nine species, Mexican stream-breeders. 27. eximia group — seven species, six Mexi- can; a North American group. 28. versicolor group — five species, one Mexican; a North American group. These groups are treated as units in the 176 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 following accounts of the species; the order of presentation does not necesarily follow the proposed phylogenetic relationships. The groups are defined principally on morphologi- cal characteristics of the adults and of the tadpoles and secondarily on breeding be- havior and distribution. Geographical distri- bution has influenced the arrangement only in a few cases of morphological similaries in widely disjunct groups of species. The Hyla rubra Group Definition: The members of this group are small to moderate-sized species. Among the Middle American species, males attain a maximum snout- vent length of 49 mm. and females, 53 mm. (table 16). The dorsum is yellowish tan, gray, or olive-green with darker blotches or longitudinal markings. The pos- terior surfaces of the thighs are either a uni- form yellow or grayish tan, or are marked with broad vertical black bars or black reticu- lations enclosing yellow spots. The snout is acuminate and protruding, and the palpebral membrane is clear. The webbing is reduced or absent on the hand (fig. 68). The webbing is absent between the first and second toes or reduced to a fringe on the second toe; otherwise the toes are one-half to two-thirds webbed (fig. 69). Dermal folds and append- ages are lacking on the limbs, and the axil- lary membrane is absent. The tarsal fold is weak or absent. Males have a single, median, subgular vocal sac, but lack nuptial excres- cences on the pollices. The skull is moderately well ossified (fig. 70) and longer than wide. The large nasals comprise more than 40 per cent of the length of the skull and have long, pointed maxillary processes. The maxillary has a small ventromedial palatine process. The palatines are slender or absent ( H, stauf- feri). A frontoparietal fontanelle is present or absent. The sphenethmoid is wider than long. The quadratojugal is slender and al- ways joined to the maxillary by a bony suture. The anterior arm of the squamosal extends about half of the distance to the maxillary. Maxillary, premaxillary, and prevomerine teeth are present. The tadpoles have deep, pointed or xiphicercal tails; the mouth is an- teroventral with two upper and three lower rows of teeth and with the median part of the upper lip devoid of papillae ( figs. 71 and 72). The mating call consists of one long, pulsed note or a series of short notes (table 17). In those species for which counts have been obtained the haploid number of chromo- somes is 12. Composition: About 24 species are cur- rently recognized; most of these occur in southeastern Brasil or in Amazonian South America. Five species, one with two subspe- cies occur in Middle America. Of these, Hyla elaeochroa and staufferi are restricted to Mid- dle America. One species, rostrata, occurs in Panama and northern Colombia and Vene- zuela, whereas boulengeri occurs on the Pa- cific lowlands of South America, and rubra is widespread in South America. Of the five Middle American species, 3113 preserved frogs, 52 skeletons, 12 lots of tadpoles, and three preserved clutches of eggs have been examined. Comments: The taxonomy of the Hyla rubra group was treated in detail by Leon (1969); much of the information presented in the following accounts of the species is summarized from his work. The Hyla rubra group is highly diversified in South America. The taxonomy of the group is complex and poorly understood. Appar- ently at least two subgroups are present in South America. One of these contains the medium-sized species and is represented in Middle America by boulengeri and rostrata. The second group is composed of smaller frogs and is represented in Middle America by elaeochroa, rubra, and staufferi. Evidently the differentiation of these groups took place in South America prior to the late Pliocene. The osteological characters given in the preceding definition are constant among those species of the group that have been studied. Other aspects of the cranial osteology show specific differences (fig. 70); some of these are compared in table 18, and all of them are described by Leon ( 1969 ) . The tadpoles of Hyla rubra and elaeochroa are alike in having xiphicercal tails and mod- erately low fins. The tadpoles of staufferi are somewhat intermediate in shape and propor- tions between the former and the tadpoles of boulengeri and rostrata, which have deep cau- dal fins (figs. 71 and 72). 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, 03 "* Q CS CS 03 X> a z 2 „° c ft b cs c a 43 .3i co C 43 c J-1 •-1 ft 03 ^ 03 c cS c c CS 03 CS S cs CO vi ft O £ £ ft OO 03 C CS ft ft a 2 "3 ■ e c « c o CS V a «3 m C S 4-. U c a » °< -« 5 03 s3' i oPa 13 . |£ » o C3T3 as cd o Zed I 8 c s CJ S »> E Co O 03 -a & 03 m a S 1970 DUELLMAN: HYLID FROGS 183 Fig. 72. Mouthparts of tadpoles of the Middle American species in the Hijla rubra group. A. H. rubra, K.U. No. 109492. B. H. elaeochroa, K.U. No. 104134. C. H. staufferi, K.U. 104162. D. H. boulengeri, K.U. No. 104295. E. H. rostrata, K.U. No. 104244. x 20. An adequate understanding of the Hyla rubra group must await a thorough study of the many species in South America. Hyla rubra Laurenti Hyla rubra Laurenti, 1768, p. 35 [no specimen designated; locality "America"]. Daudin, 1802, p. 26 [no specimen designated; locality, "Surinam"; Marin de Baize collector (?)]. Boulenger, 1882a, p. 403. Leon, 1969, p. 524. Calamita rubra: Merrem, 1830, p. 171. Auletris rubra: Wagler, 1830, p. 201. Dendrohyas rubra: Tschudi, p. 74. Scytopis ruber: Cope, 1874, p. 124. Hyla elaeochroa (part): Dunn and Emlen, 1932, p. 25. Diagnosis: Hyla rubra can be distin- guished from other Middle American species in the Hyla rubra group by having bold dark brown or black reticulations enclosing bright yellow (creamy tan in preservative) spots on the posterior surfaces of the thighs. Struc- turally, rubra is similar to elaeochroa, which differs in having the posterior surfaces of the thighs uniform pale yellow or with suffuse olive-tan mottling. Furthermore, in most specimens of rubra distinct pale dorsolateral stripes, and usually a middorsal stripe, are present. In elaeochroa the stripes, if present, are only faintly discernible in most specimens. Other Middle American species in the Hyla rubra group differ from rubra either by being smaller and having uniformly colored thighs (staufferi) or by being larger and having vertical black bars on the posterior surfaces of the thighs (boulengeri and rostrata). The protruding snout, reduced web between the first and second toes, and reticulate pattern on the posterior surfaces of the thighs dis- tinguish rubra from all other Middle Ameri- can hylids. 184 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Description: This is a medium-sized spe- cies in the Hyla rubra group. Adult males attain a snout-vent length of 35.2 mm., and females reach 40.8 mm. In a series of 17 males from Santa Cecilia, Napo Province, Ecuador, the snout-vent length is 30.9 to 33.6 (mean, 32.2) mm.; the ratio of the tibia length to snout-vent length is 0.496 to 0.520 (mean, 0.510); the ratio of foot length to snout-vent length is 0.420 to 0.453 (mean, 0.443); the ratio of head length to snout-vent length is 0.354 to 0.377 (mean, 0.367); the ratio of head width to snout-vent length is 0.310 to 0.324 (mean, 0.317), and the ratio of the diameter of the tympanum to that of the eye is 0.486 to 0.563 (mean, 0.537). In four females from the same locality the snout- vent length is 37.2 to 40.1 (mean, 38.6) mm. The females differ from the males in having a proportionately larger tympanum; the ratio of the diameter of the tympanum to that of the eye is 0.577 to 0.609 (mean, 0.592). No significant differences in size or proportions exist between the samples from Napo Prov- ince, Ecuador, and the few specimens avail- able from eastern Panama. The head is slightly narrower than the body, and the top of the head is barely convex. In dorsal profile the snout is acutely rounded with a small terminal point; in lateral profile the snout is acutely rounded and noticeably protruding beyond the leading edge of the lower jaw. The snout is long; the nostrils are noticeably protuberant and situated about three-fourths the distance from the eyes to the tip of the snout. The canthus is round and indistinct. The loreal region is barely concave and is inclined laterally; the lips are thin and flared. An indistinct dermal fold extends from the posterior edge of the eye, above the tym- panum, and downward to a point above the insertion of the arm. In some specimens this fold obscures the upper edge of the tympan- um, which otherwise is distinct and separated from the eye by a distance slightly less than the diameter of the tympanum. The arms are moderately long and slen- der; an abbreviated axillary membrane is pres- ent. There are no tubercles or dermal folds along the ventrolateral edge of the forearm, but a distinct dermal fold is present on the wrist. The fingers are moderately long and slender and have large, bluntly rounded (nearly truncate) discs. The width of the disc on the third finger is slightly greater than the diameter of the tympanum. The subarticu- lar tubercles are small and conical; none is bifid, and the distal tubercles on the first and fourth fingers are noticeably larger than the others. The supernumerary tubercles are small and subcorneal; they are arranged ir- regularly or in two rows on the proximal seg- ments of the digits. A broad, flat, bifid or tripartite outer palmar tubercle is present. The prepollex is barely enlarged, and in breeding males there is no nuptial excresence. Webbing is absent between the fingers ( fig. 68A ) . The hind limbs are moderately short and robust; the heels of the adpressed limbs overlap by about one-fifth of the length of the shank. The tibiotarsal articulation extends to the middle of the eye. A distinct transverse dermal fold is present on the heel, but the tarsal fold is absent. The inner metatarsal tubercle is broad, low, flat, and not visible from above. The outer metatarsal tubercle is distinct and coni- cal. The toes are moderately long and slender; they bear discs that are slightly smaller than those on the fingers. The subarticular tuber- cles are low and subcorneal. Distinct, conical supernumerary tubercles are present in a sin- gle row on the proximal segment of each digit. The toes are about three-fourths webbed (fig. 69A). Between the first and second toes the webbing is present only as a fringe along the edge of the second toe; the webbing extends from the distal end of the penultimate phalanx of the second to the distal end of the penulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed ventrally near the upper levels of the thighs and is covered by a short, down-curved anal sheath. Anal tubercles are absent. The skin is granular on the belly and on the proximal posteroventral surfaces of the thighs; elsewhere the skin is smooth. The tongue is cordiform, shallowly notched behind, and barely free posteriorly. The dentigerous processes of the prevomers are elevated posterolateral^ inclined ridges between the small ovoid choanae. Males have 1970 DUELLMAN: HYLID FROGS 185 four to six teeth on each ridge and a total of nine to 12 teeth (mean, 17 specimens from Santa Cecilia, 10.6). Females have six to eight teeth on each ridge and a total of 13 to 16 teeth (mean, four specimens from Santa Ce- cilia, 14.2). The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, sub gular, and moderately distensible. Because the color pattern is faded in mos> of the existing museum specimens of Hyla rubra from Central America and because I have not seen living specimens of this species from Central America, unless otherwise indi- cated, the following notes on coloration are based on specimens from Napo Province, Ecuador. The general coloration of Hyla ru- bra is pale olive-brown or grayish brown with lighter longitudinal markings (pi. 47, fig. 4). At night the frogs are pale dull yellow with or without faint tan dorsal markings. The pos- terior surfaces of the thighs, and in some speci- mens, the anterior surfaces of the thighs also, are yellow with dark brown or black mottling. The belly is creamy yellow and the vocal sac is bright yellow. By day, the dorsum is tan, brown, or gray with pale longitudinal mark- ings. The mottling on the flanks and thighs is more contrasting than at night. In some specimens, the flanks are yellow with brown or black reticulations tending to enclose small yellow spots. In other individuals the flanks are creamy yellow with black, brown, or olive flecks. In all individuals, the proximal anterior surfaces of the thighs, posterior surfaces of the thighs, and the inner surfaces of the shanks have dark brown or black reticulations enclos- ing deep yellow spots ( fig. 73 ) . In some speci- mens, the groin is immaculate yellow. The iris is bronze with black reticulations. In preservative, the dorsum is tan or olive- brown, usually with distinct dorsolateral creamy tan or dull grayish tan stripes that ex- tend to the sacral region. In some individuals a distinct, irregular middorsal stripe is pres- ent. The flanks are creamy tan with brown flecks or mottling. The proximal anterior sur- faces of the thighs, the posterior surfaces of the thighs, and the inner surfaces of the shanks are creamy tan with dark brown or black reticulations or mottling. The venter is creamy white. Faint transverse bands are Fig. 73. Posterior surface of right thigh of Hyla rubra showing typical color pattern, K.U. No. 109470. X 4. discernible on the dorsal surfaces of the shanks and feet in some individuals. The coloration of the posterior surfaces of the thighs of the Panamanian specimens is variable. In most individuals, the reticulations are less well developed than in the Ecuadorian specimens. In some specimens, such as M.C.Z. No. 13248 and U.S.N.M. No. 37863, an elon- gate creamy yellow bar on the posterior sur- faces of the thighs is narrowly outlined with black. In one specimen from Madden Dam (F.M.N.H. No. 67820) dark spots are present in the groin, on the ventral surfaces of shanks, and on the anterior surfaces of the thighs, but the posterior surfaces of the thighs are marked only by a small longitudinal yellow mark proxi- mally that is outlined by black. In M.C.Z. No. 1398, the posterior surfaces of the thighs are marked by narrow, short vertical black lines, and in M.C.Z. No. 17581 three or four small black spots are present on the posterior surface of each thigh. In M.C.Z. No. 1399 the dorsum is cream with dark brown and black mottling extending on to the dorsal surfaces of the limbs, the posterior surfaces of the thighs, and into the groin; the anterior surfaces of the thighs and ventral surfaces of the shanks and thighs are creamy tan with small brown spots. Two specimens from El Real, Darien Province, Panama (U.S.N.M. Nos. 140571 and 140572), lack spots or markings in the groin and on the thighs and shanks. Otherwise, they do not differ from the specimens of Hyla rubra. Tadpoles: No tadpoles of this species are 186 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 known from Central America. The following description is based on specimens obtained at Santa Cecilia, Napo Province, Ecuador (K.U. No. 109492). A typical tadpole in develop- mental stage 36 has a body length of 8.4 mm. and a total length of 24.3 mm. The body is slightly deeper than wide. In dorsal profile the snout is bluntly rounded and in lateral profile more acutely rounded. The nostrils are large, situated midway between the eyes and the tip of the snout and directed anterodor- sally. The eyes are moderately large and di- rected laterally. The spiracle is sinistral, and the spiracular opening is below the midline at a point about two-thirds the length of the body. The anal tube is moderately long and sinistral. The caudal musculature is slender and tapers to a very slender tip distally. At midlength of the tail the musculature is shal- lower than either the dorsal or ventral fin. The dorsal fin extends well onto the body; terminally, the fins are shallow, so as to form a xiphicercal tail (fig. 71A). In life, the body is iridescent silvery-gold laterally. The dorsum and the dorsal fin are yellowish tan with darker brown flecks. In preservative the body is creamy tan. A brown stripe extends from the snout to the eye. Brown spots are present on the sides of the body and on the caudal musculature, and gray flecks are present on the fins. The mouth is small and anteroventral in position. Deep lateral folds are present in the lips. The median part of the upper lip is bare; the rest of the upper lip is bordered by one row of long papillae. Two or three rows of papillae are present on the lower lip, and addi- tional papillae are present in the lateral fold. The beaks are robust and bear fine serrations. The upper beak is in the form of a broad arch with slender lateral processes; the lower beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows are equal in length and extend to the labial papillae; the second upper row is nar- rowly interrupted medially. The lower rows are slightly shorter than the upper ones; the third lower row is shorter than the others. All lower rows are complete (fig. 72A). Mating Call: Calls of Hijla rubra were recorded at Santa Cecilia, Napo Province, Ecuador. The calls have one to 10 notes per call group; call groups are repeated at inter- vals of four to 33 seconds. The short notes have a duration of 0.12 to 0.15 of a second and a pulse rate of 61 to 65 pulses per second. The average fundamental frequency is 61 cy- cles per second and the average dominant frequency is 1581 cycles per second (table 17, pl. 27, fig. 1). Natural History: No definite informa- tion is available concerning the natural history of Hyla rubra in Central America. On the basis of the localities from which the species is known in Central America, it can be sur- mised that it is a species that breeds in the rainy season in shallow, temporary ponds. In Napo Province, Ecuador, Hyla rubra is one of the most abundant hylids in the tropical rain forest. By day, individuals were found in bromeliads and in other sheltered places above the ground. Males call from bushes and herbs at the edge of small rain pools. Gravid fe- males were abundant in February, March, and June. The tadpoles develop in shallow muddy pools, where they hide amidst the aquatic vegetation and frequently swim to the surface. When disturbed, the tadpoles seek refuge in the vegetation or in the mud at the bottom of the pool. Remarks: The use and application of the name of Hyla rubra is confused. Leon ( 1969, p. 524) discussed the nomenclatural problems regarding Hyla rubra: "The taxonomic his- tory of Hyla rubra Laurenti is confused. Seba ( 1734:70) illustrated and diagnosed a form for which he used the name 'Ranula, Americana, Rubra.' Linnaeus (1758:213) considered Se- ba's frog to be a variety of Hyla arborea. Lau- renti (1768:35) apparently examined the same individual that Seba called 'Ranula, Ameri- cana, Rubra.' For this specimen, Laurenti used the binomial Hyla rubra and provided a brief diagnosis. The type locality was given as 'America.' "Daudin (1802:26) redescribed the same specimen (s?) treated by Seba and Laurenti and provided a fairly good description and fig- ure. Daudin restricted the type locality to Surinam and indicated that Marin de Baize was the probable collector. Daudin (1802:26 and 1803:53) neglected to consider Laurenti's work, but he applied the same name used by 1970 DUELLMAN: HYLID FROGS 187 Laurenti. Most authors have credited Hyla rubra to Daudin, but Rivero (1961:120) noted that Hyla rubra Laurenti, 1768, has priority over Hyla rubra Daudin, 1802. Since both Laurenti and Daudin worked on Seba's ma- teria], it is reasonable to assume that Daudin redescribed the same frogs that were named by Laurenti; this was not an uncommon prac- tice in the early nineteenth century. Thus, I conclude that Hyla rubra Daudin, 1802, is a junior primary homonym of Hyla rubra Lau- renti, 1768." The matter of the authority for the name is problematical. It is impossible to determine whether Daudin merely redescribed the frog named Hyla rubra by Laurenti or whether he inadvertently proposed the same specific name for what might be a different species of frog. Because there is no way of definitely settling this question, I agree with Leon that it is best to consider Hyla rubra Daudin, 1802, to be a junior primary homonym of Hyla rubra Lau- renti, 1768. Even if the nomenclature is set- tled in this manner, the biological problem of the application of the name Hyla rubra to a definite population of frogs still remains. At this time, the taxonomy of Hyla rubra in South America is too poorly known to determine whether or not the widespread species now known as Hyla rubra is actually one species or a composite of two or more species. Conse- quently, I have chosen the conservative ap- proach and have applied the name Hyla rubra to the Central American populations. Dunn (1931b, p. 413) reported Hyla rubra from the Canal Zone and San Pablo, Panama. Subsequently, Dunn and Emlen (1932, p. 25) and Dunn (1933, p. 61) listed specimens of Hyla rubra from Nicaragua, Costa Rica, and western Panama. At that time, Dunn was under the impression that Hyla elacochroa was a synonym of Hyla rubra. Subsequent study has revealed that Hyla elaeochroa is a distinct species. Consequently, the records of Hyla rubra reported by Dunn and Emlen, and by Dunn in his later paper are actually based on Hyla elaeochroa. Three specimens from El Real, Darien Province, Panama (U.S.N.M. Nos. 140569, 140570, and 140573), are discussed here, al- though these individuals probably do not rep- resent Hyla rubra. All three are males, having snout-vent lengths of 40.6 to 42.6 (mean, 41.1) mm. Thus, they are larger than the known females from Panama, in which the snout-vent length is 35.5 to 40.8 (mean, 4 specimens, 38.4) mm. In proportions, these three males differ from six males of Hyla rubra from Panama by having proportionately shorter tibia and nar- rower heads. In these three males, the ratio of the tibia length to the snout-vent length is 0.484 to 0.512 (mean, 0.496), as compared with 0.501 to 0.548 (mean, 0.528) in Pana- manian Hyla rubra. The ratio of head width to snout-vent length is 0.295 to 0.315 (mean, 0.306), as compared with 0.300 to 0.342 ( mean, 0.331 ) . Likewise, the tympanum is proportionately larger in these three males; the ratio of the diameter of the tympanum to that of the eye is 0.600 to 0.619 (mean, 0.611), as compared with 0.473 to 0.667 (mean, 0.559) in the Panamanian Hyla rubra. The three males from El Real have no spots or markings in the groin. The flanks are plain or weakly mottled; small black spots are present on the anterior surfaces of the thighs and on the ventral surfaces of the shanks. The posterior surfaces of the thighs are pale brown with an elongate creamy white spot in which black dashes or small spots are present. I have no knowledge of the coloration of these frogs in life. It is highly probable that these three specimens represent a species distinct from Hyla rubra. Similar large rubra-\ike frogs are known to occur sympatrically with Hyla rubra in northern Venezuela and the Guianas, but the taxonomic status of these, like those in Panama, is unknown." Etymology: The specific name rubra is Latin meaning red. The application of this specific name by Laurenti and Daudin appar- ently is based on Seba's usage of the name. Distribution: In Central America, Hyla rubra is known from the Canal Zone and east- ward on the Pacific lowlands of Panama (fig. 7 Recently I have seen additional specimens of this large H. ntbra-]ike frog from Achiote, Colon Province, Panama (U.F. Nos. 27001-12, 27018) and from Ya- visa, Darien Province, Panama ( M.V.Z. Nos. 83191- 98). A recent specimen (K.U. No. 125026) from 5 kilometers east of Achiote, Colon Province, Panama, collected by Dr. Sam R. Telford, Jr., is a member of the Hyla rubra group but is unlike any other specimen of the group known to me. Possibly the specimen is a hybrid between rubra and boulengeri. 188 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 82° 80° 78° • H. elaeochroa O H rubra 50 — i — 100 KILOMETERS 12" 10° 84° Fig. 74. Distribution of Hyla rubra and Hyla elaeochroa. 74). In South America, the frogs known by the name of Hyla rubra occur throughout the lowlands of northern South America and of the Amazon Basin. See Appendix 1 for the locality records of the 32 specimens examined. Hyla elaeochroa Cope Hyla elaeochroa Cope, 1876 [lectotype, U.S.N.M. No. 30689 from the east foot of mountains near Sipurio, Limon Province, Costa Rica: William M. Gabb collector]. Brocchi, 1882, p. 39. Boulenger, 1882a, p. 399. Gunther, 1901 (1885-1902), p. 265. Taylor, 1952c, p. 859. Duellman, 1966b, p. 270. Leon, 1969, p. 525. Hyla quinquevittata Cope, 1886 [holotype, U.S.N.M. No. 14187 from "Nicaragua"; John F. Brans- ford collector]. Gunther, 1901 ( 1885-1902), p. 268. Hyla rubra (part) : Dunn and Emlen, 1932, p. 25. Hyla dulcensis Taylor, 1958, p. 37 [holotype, K.U. No. 32168 from Golfito, Puntarenas Province, Costa Rica; Edward H. Taylor collector]. Diagnosis: From other species in the Hyla rubra group, Hyla elaeochroa can be distin- guished by its medium size ( snout-vent length of adult males, 26.3 to 37.7 mm.) and unpat- terned posterior surfaces of the thighs; the latter character is shared with the smaller staufferi (snout-vent length of adult males, 20.6 to 29.0 mm.). Hyla elaeochroa is struc- turally similar to rubra, which differs by hav- ing bold brown or black reticulations on the posterior surfaces of the thighs. The other Middle American species in the Hyla rubra group (boulengeri and rostrata) differ from elaeochroa in larger size and by having black vertical bars on the posterior surfaces of the thighs. The combination of a long, protruding snout, vestigial webbing between the fingers, and greatly reduced webbing between the first and second toes distinguished elaeochroa from other Middle American hylids. Description: This is a medium-sized spe- cies of the Hyla rubra group; males attain a maximum snout-vent length of 37.7 mm., and females reach 40.3 mm. In a sample of 101 males from the Instituto Interamericano de 1970 DUELLMAN: HYLID FROGS 189 Ciencias Agricolas at Turrialba, Cartago Prov- ince, Costa Rica, the snout-vent length is 28.1 to 35.0 (mean, 30.6) mm.; the ratio of tibia length to snout-vent length is 0.472 to 0.550 (mean, 0.505); the ratio of foot length to snout-vent length is 0.372 to 0.441 (mean, 0.408); the ratio of head length to snout- vent length is 0.321 to 0.372 (mean, 0.342); the ratio of head width to snout-vent length is 0.293 to 0.332 (mean, 0.309), and the ratio of the diameter of the tympanum to that of the eye is 0.444 to 0.683 (mean, 0.572). In 15 females from the same locality the snout- vent length is 31.9 to 35.7 (mean, 35.0) mm. The females differ from males in proportion only in the ratio of the diameter of the tym- panum to that of the eye; in females this ratio is 0.493 to 0.645 (mean, 0.596). Speci- mens from the Golfo Dulce region in south- eastern Costa Rica differ from those from the Caribbean lowlands by being larger and hav- ing relatively longer legs, longer head, and narrower head (table 19). The head is slightly narrower than the body; the top of the head is barely convex. In dorsal profile, the snout is acutely rounded with a terminal point; in lateral profile, the snout is pointed and protruding beyond the edge of the lower jaw. The snout is long; the nostrils are protuberant and situated at about four-fifths of the distance from the eyes to the tip of the snout. The canthus is rounded, but distinct. The loreal region is barely con- cave and inclined laterally; the lips are thin and moderately flared. A thin dermal fold extends posteriorly from the posterior corner of the eye above the tympanum to a point above the insertion of the arm. The fold ob- scures the upper edge of the tympanum, which otherwise is distinct and is separated from the eye by a distance equal to the diam- eter of the tympanum. The arms are moderately long and slender; an abbreviated axillary membrane is present. No dermal folds or tubercles are present on the ventrolateral edge of the forearm, but a weak transverse dermal fold is present on the wrist. The fingers are moderately long and slender. The terminal discs are large and somewhat truncate. The width of the disc on the third finger is slightly greater than the diameter of the tympanum. The subarticular tubercles are large and round; the distal tu- bercles on the first and fourth fingers are largest. The supernumerary tubercles are small, subconical, and indistinct in many specimens. The outer palmar tubercle is large and usually bifid; in some specimens it is par- TABLE 19 Geographic Variation in Measurements and Proportions, with Means in Parentheses, in Males of Hyla elaeochroa in Costa Rica." Snout-vent Tibia Length/ Head Length/ Head Width/ Tympanum/ Locality N Length S-V L S-V L S-V L Eye Puerto Viejo 22 26.3-32.4 0.487-0.549 0.328-0.372 0.292-0.329 0.481-0.652 (29.7) (0.520) (0.352) (0.308) (0.568) Batan, Limon, Suretka 26 26.3-32.7 0.471-0.539 0.323-0.379 0.300-0.342 0.444-0.621 (30.0) (0.513) (0.349) (0.315) (0.500) Turrialba 101 28.1-35.0 0.472-0.550 0.321-0.372 0.293-0.332 0.444-0.683 (30.6) (0.505) (0.342) (0.308) (0.572) Tilaran 21 28.8-33.6 0.473-0.544 0.314-0.361 0.284-0.319 0.483-0.652 (30.6) (0.526) (0.334) (0.299) (0.587) Palmar Sur 13 29.4-35.1 0.482-0.538 0.331-0.372 0.300-0.347 0.473-0.619 (32.4) (0.508) (0.347) (0.321) (0.527) Piedras Blancas 21 33.3-37.7 0.498-0.542 0.322-0.363 0.298-0.323 0.482-0.643 (35.2) (0.511) (0.344) (0.313) (0.573) Rincon de Osa .... 24 31.4-35.9 0.500-0,559 0.322-0.369 0.299-0.339 0.452-0.612 (34.1) (0.531) (0.351) (0.319) (0.541) " Based in part on data presented by Leon (1969). 190 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 tially tripartite. The prepollex is barely en- larged and in breeding males does not bear a nuptial excrescence. Only a vestige of a web is present between the fingers ( fig. 68B ) . The hind limbs are moderately short and ro- bust; the heels of the adpressed limbs over- lap by about one-fifth the length of the shank. The tibiotarsal articulation extends to the middle of the eye. A transverse dermal fold is present on the heel, but the tarsal fold is absent. The inner metatarsal tubercle is low, rounded, ovoid, and not visible from above. The outer metatarsal tubercle is elongate and distinct. The toes are moderately long and slender and bear discs that are only slightly smaller than those on the fingers. The sub- articular tubercles are moderately large and subcorneal. The supernumerary tubercles are small, conical, distinct, and present in a single row on proximal segments of each digit. The toes are about three-fourths webbed (fig. 69B). The webbing is absent between the first and second toes, except for a narrow fringe along the edge of the second toe; the web extends from the distal end of the pen- ultimate phalanx of the second to the base of the antepenultimate phalanx of the third, from the middle of the penultimate phalanx of the third to the distal end of the antepen- ultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed ventrally near the upper level of the thighs and is cov- ered by a short, down-curved anal sheath. There are no anal tubercles. The skin on the belly and on the proximal posteroventral sur- faces of the thighs is granular; elsewhere the skin is smooth, except that in some specimens small tubercles are present on the dorsum. These usually are not evident in preserved specimens. The tongue is cordiform, shallow- ly notched behind and barely free posteriorly. The dentigerous processes of the prevomers are transverse and situated between the mod- erately large, ovoid choanae. Some males lack teeth on one of the prevomerine processes. Other individuals have as many as eight teeth on one process; the total number of prevo- merine teeth in 101 males from Turrialba, Cartago Province, Costa Rica, is three to 14 (mean, 9.9). In 15 females the total number of teeth varies from nine to 15 (mean, 11.8). The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and mod- erately distensible. The general coloration of Hyla elaeocliroa when active at night is pale yellow or yellow- ish tan with faintly darker dorsal markings (pi. 47, fig. 5). Some individuals when found by day were olive-green or tan with darker dorsal markings (pi. 47, fig. 6). In these speci- mens, the axillary region and edge of the throat often are pale bluish gray, whereas the belly is creamy white. In specimens that were ac- tive at night, the venter is pale yellow and the vocal sac is slightly darker yellow. The dorsal markings are highly variable. In some individuals, the spots are fused and aligned to form irregular longitudinal stripes. In other individuals, the spots are discreet and show no tendency toward a formation of stripes. In most individuals, a dark line extends from the tip of the snout through the nostril to the eye, and a dark interorbital triangular mark is present. The dorsal surfaces of the limbs are marked by brown transverse bands. Three to five bands are present each on the thigh, shank, and foot; two or three bands are present on the forearm. The iris is dull bronze with brown or gray suffusion, especially ventrally. In preservative, the dorsum is pale yellow- ish tan, pale gray, or brown with darker mark- ings. The anterior and posterior surfaces of the thighs are pale tan or creamy white. In many specimens the transverse marks on the limbs are not discernible in preservative. The dorsal markings are dull brown. The venter is creamy white. Leon (1969, p. 526) discussed the geo- graphic variation of color pattern in Hyla elaeochwa and stated: "In life, most indi- viduals from the Pacific lowlands of Costa Rica are dark tan to greenish gray above with longitudinal stripes that are entire or broken, but some specimens ( mostly males ) are dusty brown or lack longitudinal stripes or interor- bital triangle; females usually have the dark interorbital triangle and the stripes on the dorsum. Individuals from Turrialba, Cartago Province, Costa Rica, are pale olive-tan with olive-brown markings. Individuals from Puer- to Viejo, Heredia Province, Costa Rica, are uniformly yellowish brown with or without 1970 DUELLMAN: HYLID FROGS 191 dark longitudinal stripes. Specimens from El Reereo, Zelaya Province, Nicaragua, are like those from Puerto Viejo. Males from Almi- rante, Bocas del Toro Province, Panama, are pale brown with dark brown longitudinal stripes and an indistinct interorbital triangle. Females have a distinct interorbital triangle and dark brown blotches on the thighs and shanks." Tadpoles: Large series of tadpoles in vari- ous developmental stages were obtained from a pond at Puerto Viejo, Heredia Province, Costa Rica. The growth and development of these tadpoles is summarized in table 20 and figure 75. Examination of figure 75 reveals that the most rapid growth takes place be- tween stages 25 and 27 and again between stages 37 and 41. A typical tadpole in developmental stage 27 has a body length o*' 7.2 mm. and a total length of 21.1 mm. The body is slightly deeper than wide; the snout is bluntly rounded in dorsal profile and more acutely rounded in lateral profile. The nostrils are large, directed anterodorsally, and situated about midway between the eyes and the tip of the snout. The eyes are moderately large and directed later- ally. The spiracle is sinistral; the spiracular opening is below the midline at a point at about two-thirds the length of the body. The anal tube is short and dextral. The caudal musculature is thin and tapers posteriorly. At the midlength of the tail the depth of the musculature is less than that of either the dor- sal or ventral fin. The dorsal fin extends onto the body. Terminally, both fins narrow to a thin tip (fig. 71B). In life the dorsum is yellowish tan with T 1 T Metatarsal Tubercle Mouthparts Degenerating 35 - 30 - 25 Total Length Body Length Tail Length Mouthparts Complete L=I/2D Resorbtion of Tail E -! 20 15 10 _L _L 24 26 28 30 32 34 36 Developmental Stages 38 40 42 44 46 Fig. 75. Relative rate of growth in tadpoles of Hyla elaeochroa as correlated with developmental stages. Points are means of measurements given in table 20; formulas for the limb bud refer to its length (L) in relation to basal diameter ( D ) . 192 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TARLE 20 Measurements of Tadpoles, with Means in Parentheses, in Relation to Developmental Stages of Hyla elaeochroa from Puerto Viejo, Heredia Province, Costa Rica." Stage N Body Length Tail Length Total Length 24 2 4.0 8.5- 9.0 (8.8) 12.5-13.0 (12.8) 25 64 5.0- 6.5 (5.7) 8.5-15.0 (11.8) 13.5-21.5 (17.6) 27 __ 30 7.0- 7.5 (7.1) 13.0-16.0 (14.2) 20.0-23.0 (21.3) 30 15 7.0- S.O (7.3) 13.0-16.5 (15.0) 20.0-24.0 (22.4) 32 ._ 30 7.5- 8.5 (7.8) 15.0-17.0 (16.1) 22.5-25.0 (23.8) 35 35 8.0- 9.0 (8.1) 15.0-19.5 (17.7) 23.0-27.5 (25.9) 37 22 8.5- 9.5 (9.0) 16.0-22.0 (18.8) 25.0-31.0 (27.8) 39 14 9.5-10.5 (9.9) 19.0-24.9 (21.1) 28.5-33.5 (31.0) 40 27 7.0-11.5 (9.1) 15.0-23.0 (22.0) 23.0-34.5 (31.2) 43 10 8.0-12.0 (10.2) 11.0-17.0 (13.5) 20.0-26.0 (23.7) 45 16 10.0-12.0 (11.2) 1.0- 7.0 (3.4) 12.0-17.0 (14.6) 46 45 11.0-13.0 (11.8) " Data from Leon (1969). grayish brown mottling. The belly and ventro- lateral surfaces are white, except for some grayish brown mottling below the eye. The caudal musculature and fins are similarly pig- mented with small grayish brown spots. The iris is gold with a small amount of orange peripherally in some specimens. In preserva- tive the body and caudal musculature is pale tan. A dark brown line extends from the snout to the eye and thence posteriorly to the base of the caudal musculature. Brown flecks are scattered on the body, caudal musculature, and fins. The mouth is small and anteroventral in position. Deep lateral folds are present in the lips. The median part of the upper lip is bare; the rest of the upper lip is fringed by one row of large papillae. Two or three rows are present on the lower limbs, and additional papillae are present in the lateral fold. The beaks are robust and bear fine serrations. The upper beak is in the form of an arch with long slender lateral processes; the lower beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows are equal in length and extend nearly to the lateral papillae. The second upper row is narrowly interrupted medially. The lower rows are complete and progressively shorter than the upper rows (fig. 72B). Mating Call: The call of Hyla elaeochroa consists of a series of short notes. Usually, individuals produce two to 15 notes in each call group, but some individuals have been heard to produce call groups of 61, 75, 77, and 95 notes. The average number of notes per call group is 19. Call groups are produced at intervals of 1.5 to 48 seconds. The notes have a duration of about 0.17 of a second and pulse rate of about 42 pulses per second. The average fundamental frequency is 57 cycles per second; two harmonics are emphasized; the average of the lower emphasized harmonic is 1499 cycles per second and the average of the upper emphasized harmonic is 2911 cycles per second ( table 17; pi. 26, fig. 1 ) . Natural History: Hyla elaeochroa inhab- its humid lowland tropical forests where the frog apparently is active throughout the year. Males have been heard calling in every month except December. Mating seems to be de- pendent on heavy rainfall, which not only pro- vides sufficient water in depressions to form temporary ponds, but apparently initiates the mating response on the part of the adults. Peaks of mating activity have been observed following heavy rains. At such times, large breeding congregations have been observed at Palmar and Piedras Blancas, Puntarenas Province, Costa Rica, at Tilaran, Guanacaste Province, Costa Rica, at Puerto Viejo, Heredia Province, Costa Rica, and at Turrialba, Car- tago Province, Costa Rica. Males usually call from emergent vegeta- tion at the edge of ponds, but individuals also call from low bushes in and around the ponds. 1970 DUELLMAN: HYLID FROGS 193 The normal calling sites sometimes are for- saken in large choruses following heavy rains. At such times the sexual activity on the part of the males is such that the normal mating behavior patterns break clown. An excellent example of this was observed at a small pond at Puerto Viejo, Heredia Province, Costa Rica, on the night of June 20, 1966 ( pi. 10, fig. 1 ) . Immediately following four hours of torren- tial rains, Hijla elaeochwa moved into the pond in great numbers. An estimated 3,000 frogs of this one species was present in a pond. Six calling males and two clasping pairs were observed on one Monstera leaf about 200 centi- meters in diameter. In an estimated one square meter of herbs in shallow water, 27 calling males were present. Fifty-nine Hyla elaeochwa were observed on one stump ap- proximately 1.5 meters in height and 70 cm. in diameter. Males were calling from the ground as well as while floating in the water. Succeeding nights at the same ponds, showed a decrease in the activity of this species and a resumption of normal sites and calling be- havior (Duellman, 1967c, p. 175). Duellman (1967a, p. 160) discussed the socialization in the call structure of Hyla elaeochwa. Observations made at La Lola, Limon Province, and at Palmar Sur, Punta- renas Province, Costa Rica showed that in small choruses (up to about 20 males) initial organization is present in the chorus structure. An apparent dominant individual initiates the chorus by producing a single pulsed note until joined by a second individual which also pro- duces a single pulsed note. These call alter- nately until joined by a third frog, at which time the entire chorus begins calling with the regular series of short notes characteristic of the mating call. It is highly doubtful if such initial organization exists in large choruses, such as that observed at Puerto Viejo on June 20, 1966. The eggs are deposited in mass in water adjacent to or adhering to floating vegetation. Hatchlings orient themselves vertically with the tip of the mouth to the surface of the water. They gradually sink to the bottom and then swim back to the surface again. Tad- poles in later stages of development ( stage 25 and beyond) live in the shallow water near the edges of the pond and hide in the vegeta- tion. Metamorphosing young have been found from June through September. Forty-five re- cently metamorphosed individuals from Puerto Viejo have snout-vent lengths of 11.0 to 13.0 (mean, 11.8) mm. Remarks: Dunn and Emlen (1932, p. 25) considered Hyla elaeochwa and quinquevit- tata to be synonyms of Hyla rubra. Taylor ( 1952c, p. 859) regarded quinquevittata as a synonym of elaeochwa, which he considered to be distinct from rubra. Taylor (1958) de- scribed Hyla dulcensis from the Golfo Dulce region in southeastern Costa Rica. Duellman ( 1966b) after comparing adults, tadpoles, and mating calls of dulcensis and elaeochwa, con- cluded that a single species was involved. Leon (1969), reached the same conclusion. Etymology: The specific name elaeochwa is derived from the Greek elaia, meaning olive and the Greek chroa, meaning color of skin; the name obviously refers to the pale olive- colored dorsum. Distribution: Hyla elaeochwa inhabits the Caribbean lowlands from east-central Nicaragua to western Panama and the Pacific lowlands of southeastern Costa Rica and ex- treme western Panama (fig. 74). Most of the localities where the species has been collected are below 800 meters in elevation, but the species has been found at two localities above 1000 meters ( El Silencio and Pacuare, Cartago Province ) on the Caribbean slopes of the Cor- dillera de Talamanca, Costa Rica. See Appendix 1 for the locality records of the 811 specimens examined. Hyla staufferi Cope Hyla staufferi Cope, 1865b, p. 195. Diagnosis: This small species is distin- guished from other Middle American members of the Hyla rubra group by its small size (max- imum snout-vent length in males, 29.0 mm., and in females, 31.6 mm.), presence of dark longitudinal markings on the body, and ab- sence of markings on the thighs. These char- acters, plus the pointed protruding snout, ves- tigial webbing between the fingers, and re- duced webbing between the first and second toes, distinguish staufferi from all other Mid- dle American hylids. 194 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Content: Two subspecies are recognized: Hyla s. staufferi Cope inhabits subhumid low- lands from Mexico to south-central Costa Rica, and H. s. altae Dunn occurs on the Pacific lowlands of western and central Panama. Minor differences in the ratio of tibia length to snout-vent length and in the ratio of the diameter of the tympanum to that of the eye exist throughout the range, but a trend is present from north to south for shorter snout-vent length, relatively shorter hindlimbs, and relatively smaller tympani ( table 21 ) . The primary difference between the subspecies is in the color pattern. In the Panamanian subspecies, the stripes on the dorsum are usually complete and the shanks are not barred, whereas in any given sample Fig. 76. Color pattern on the dorsal surface of the shank in Ht/la staufferi. A. H. s. staufferi, K.U. No. 87081. B. H. s. altae, K.U. No. 77341. x 4. Fig. 77. Distribution of the subspecies of Hyla staufferi 1970 DUELLMAN: HYLID FROGS 195 TABLE 21 Geographic Variation in Size, Proportions, and Color Pattern in Males of Hyla staufferi:' (Means are given in Parentheses) Locality N Veracruz, Mexico 47 Campeche, Mexico 20 Oaxaca, Mexico 29 Chiapas, Mexico 20 El Peten, Guatemala .... 32 Jalapa, Guatemala 44 Esquipulas, Guatemala 18 Snout-vent Length (mm.) Tibia Length/ S-V L Tympanum/ Eye Complete Barred Dorsal Stripes Shanks (per cent) (per cent) San Salvador, El Salvador 31 Choluteca, Honduras . 21 Chinandega, Nicaragua 18 Rivas, Nicaragua ..... .. 35 Guanacaste, Costa Rica 54 Western Panama 46 Central Panama 26 23.0-27.3 (25.4) 24.6-27.5 (25.5) 24.3-28.7 (26.5) 23.2-27.S (25.5) 21.5-25.2 (23.5) 23.8-29.0 (26.9) 21.1-27.2 (25.6) 24.7-28.6 (27.0) 24.0-27.8 (26.4) 23.0-27.2 (25.1) 21.5-26,8 (24.3) 20.7-26.6 (24.2) 21.7-26.0 (23.7) 22.2-25.8 (23.5) 0.460-0.519 (0.483) 0.414-0.487 (0.458) 0.432-0.499 (0.462) 0.421-0.499 (0.467) 0.434-0.536 (0.490) 0.441-0.498 (0.471) 0.444-0.526 (0.479) 0.442-0.517 (0.471) 0.424-0.536 (0.478) 0.480-0.535 (0.511) 0.461-0.529 (0.494) 0.448-0.510 (0.483) 0.431-0.398 (0.454) 0.413-0.472 (0.444) 0.482-0.678 (0.601) 0.523-0.703 (0.615) 0.524-0.759 (0.618) 0.600-0.750 (0.712) 0.523-0.768 (0.627) 0.573-0.752 (0.672) 0.553-0.761 (0.622) 0.484-0.697 (0.598) 0.482-0.700 (0.599) 0.547-0.702 (0.574) 0.484-0.749 (0.628) 0.481-0.672 (0.583) 0.452-0.719 (0.567) 0.498-0.583 (0.527) 0.0 0.0 9.3 10.0 8.4 11.1 3.9 0.0 3.3 0.0 3.0 5.5 93.5 96.3 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 92.7 98.1 0.0 0.0 a Based in part on data presented by Leon (1969). from Costa Rica northward no more than 11 per cent of the specimens have complete stripes on the dorsum and no fewer than 92 per cent have transverse bars on the shanks (fig. 76). Secondary differences exist in size and in the amount of webbing on the feet; in Panamanian specimens the toes are about two- fifths webbed, whereas in Costa Rica and northward the toes are about three-fourths webbed. Furthermore, minor differences exist in the mating calls; the duration of the notes is shorter and the major emphasized frequen- cies are higher in the Panamanian subspecies (table 17). Distribution: Hyla staufferi occurs at moderate and low elevations from southern Tamaulipas, Mexico, to Nicaragua on the Caribbean versant and from Guerrero, Mex- ico, to south-central Costa Rica on the Pacific versant, and on the Pacific lowlands of western and central Panama (fig. 77). Hyla staufferi staufferi Cope Hyla staufferi Cope, 1865b, p. 195 [holotype, U.S.N.M. No. 15317 from Orizaba, Veracruz. Mexico; Francis Sumichast collector J. Brocchi, 1882, p. 36. Boulenger, 1882a, p. 400. Kellogg, 1932, p. 173. Smith and Taylor, 1948, p. 88. Stuart, 1963, p. 36. 196 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Hyla eximia staufferi Cope. 1887, p. 14. Hyla eximia (part): Gunther, 1901 (1885-1902), p. 261. Hi/hi culex Dunn and Emlen, 1932, p. 24 [holo- type, M.C.Z. No. 16098 from Tela, Departamento At- lantidad, Honduras; Raymond A. Stadelman collector]. Hyla staufferi (part): Taylor, 1952c, p. 862. Duell- man, 1966b, p. 274. Hyla staufferi staufferi: Leon, 1969, p. 537. Diagnosis: Hijla s. staufferi differs from all other Middle American hylids by having an acuminate, protruding snout, transverse bars on the shanks, a dorsal pattern consisting of a dark triangular interorbital mark and inter- rupted longitudinal dark marks, and vestigial webbing on the hands. The subspecies H. s. altae differs by having complete longitudinal stripes on the dorsum and in lacking trans- verse bars on the shanks. Hyla elaeochroa differs by being larger and in having a more irregular dorsal pattern, and H. rubra differs by having dark brown or black reticulations enclosing yellow spots on the posterior sur- faces of the thighs. Description: Males of this small subspe- cies attain a maximum snout-vent length of 29.0 mm., and females reach 31.6 mm. In a series of 29 males from the vicinity of Liberia, Guanacaste Province, Costa Rica, the snout- vent length is 20.7 to 26.1 (mean, 24.1) mm.; the ratio of tibia length to snout-vent length is 0.448 to 0.510 (mean, 0.488); the ratio of foot length to snout-vent length is 0.363 to 0.439 (mean, 0.398); the ratio of head length to snout-vent length is 0.313 to 0.368 (mean, 0.340); the ratio of head width to snout-vent length is 0.233 to 0.303 (mean, 0.275), and the ratio of the diameter of the tympanum to that of the eye is 0.481 to 0.667 ( mean, 0.585 ) . Seven females from the same locality have snout-vent lengths of 25.7 to 28.0 (mean, 26.6) mm. In proportions the females differ from the males only by having a slightly higher ratio of the diameter of the tympanum to that of the eye— 0.482 to 0.706 (mean, 0.614). Specimens from farther north, particularly from Oaxaca, Mexico, central Guatemala, and from El Salva- dor, are larger than those from the southern part of the range in Nicaragua and Costa Rica. Slight trends are apparent from north to south; the relative length of the tibia and the relative diameter of the tympanum decrease from Mexico southward to Costa Rica (table 21). The head is no wider than the body; the top of the head is convex. In dorsal and lateral profiles, the snout is pointed; the snout projects beyond the leading edge of the lower jaw. The snout is long; the nostrils are barely protuberant and are situated at about four- fifths the distance from the eyes to the tip of the snout. The canthus is rounded and barely distinct; the loreal region is slightly concave, and the lips are thin and moderately flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, and terminates at a point above the insertion of the arm. In some specimens, the dermal fold obscures the upper edge of the tympanum, which other- wise is distinct and is separated from the eye by a distance equal to the diameter of the tympanum. The arms are moderately long and slender; an abbreviated axillary membrane is present. There are no tubercles forming a row on the ventrolateral edge of the forearm, but a weak dermal fold is present on the wrist. The fin- gers are moderately short and stout and bear moderately large, barely truncate discs; the width of the disc on the third finger is about equal to the diameter of the tympanum. The subarticular tubercles are large and round; none are bifid. The supernumerary tubercles are small, subconical, and arranged in a single row on the proximal segment of each digit. The palmar tubercle is large, rounded, and bifid. The prepollex is barely enlarged; in breeding males it does not bear a nuptial excrescence. Webbing is essentially absent between fingers (fig. 68C). The hindlimbs are relatively short and robust; the heels of the adpressed limbs overlap by about one-fifth the length of the shank. The tibiotarsal articu- lation extends to the posterior edge of the orbit. A weak transverse dermal fold is pres- ent on the heel, but the tarsal fold is lacking. The inner metatarsal tubercle is moderately large, rounded, ovoid, and barely, if at all, visible from above. The outer metatarsal tu- bercle is small and conical. The toes are mod- erately long and slender and bear discs that are noticeably smaller than those on the fin- gers. The subarticular tubercles are moder- ately large and round. The supernumerary 1970 DUELLMAN. HYLID FROGS 197 tubercles are small, indistinct, or even absent in many specimens, and when present ar- ranged in a single row on the proximal seg- ment of the fourth and fifth digits; in some individuals faint supernumerary tubercles are evident on the second and third digits. The toes are about two-thirds webbed ( fig. 69C ) . The webbing is vestigial between the first and second toes; it extends from the distal end of the penultimate phalanx of the second to the middle of the antepenultimate phalanx of the third, from the middle of the penultimate phalanx of the third to the middle of the ante- penultimate phalanx of the fourth and from the distal end of the antepenultimate phalanx of the fourth to the distal end of the penulti- mate phalanx of the fifth toe. The anal opening is directed posteriorly near the level of the upper edges of the thighs. A short, broad anal sheath is present; small tubercles are present below the anal opening. The skin on the belly and proximal postero- ventral surfaces of the thighs is granular; else- where the skin is smooth. The tongue is ovoid, widest posteriorly, or cordiform with a shallow notch posteriorly. The dentigerous processes of the prevomers are transverse between the posterior margins of the elliptical choanae or are slightly posteromedially inclined. In the series of males from Liberia, one to six teeth arc present on each prevomerine process; these specimens have a total of five to 11 (mean, 7.8) prevomerine teeth. In the females from the same locality, three to six teeth are present on each process, and the total number of pre- vomerine teeth is six to 11 (mean, 8.9). The vocal slits extend on the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly dis- tensible. The general coloration of Hyla staufferi stau fferi is tan, olive-tan, or dull brown with irregular darker markings on the back and dor- sal surfaces of the limbs (pi. 47, figs. 1 and 2). The dorsal markings usually consist of a dark interorbital spot and irregular longitudinal marks on the dorsum; in a few specimens from the southern part of the range the dorsal mark- ings form distinct, continuous longitudinal stripes. Two or three dark transverse bars are present on each of the thigh, shank, and fore- arm. A narrow dark brown line extends from the nostril to the eye and along the edge of the supratympanic fold. The flanks are creamy white or creamy tan, usually with dark brown or black flecks. The belly is creamy white, and the vocal sac in breeding males is dark yellow. The posterior surfaces of the thighs are dull brown. The iris is dull bronze with a heavy suffusion of brown. In preservative the dorsum is pale tan or gray with brown markings. The posterior sur- faces of the thighs are dull brown and the ventral surfaces are creamy tan. Tadpoles: Small series of tadpoles in vari- ous developmental stages were reported on by Leon (1969). A typical tadpole in develop- mental stage 38 has a body length of 10.0 mm. and a total length of 28.2 mm. The body is deeper than wide. The snout is bluntly rounded in dorsal profile and deeply inclined anteroventrally in lateral profile. The nostrils are large, directed anterodorsally, and situ- ated about midway between the eyes and the tip of the snout. The eyes are moderately large and directed laterally. The opening of the sinistral spiracle is directed posterodorsally at a point below the midline and at about two- thirds of the distance from the snout to the posterior edge of the body. The anal tube is short and dextral. The caudal muscula- ture is slender and tapers to a long point terminally. At midlength of the tail, the depth of the caudal musculature is much less than the depth of either the dorsal or ventral fins. The dorsal fin extends well onto the body, is deepest at midlength of the tail, and tapers to a shallow point posteriorly. The ventral fin has an equal depth on the anterior half of the tail and posteriorly tapers gradually to a terminal point (fig. 71C). In life the body and caudal musculature is pale tan; dark brown reticulations are pres- ent on the tail. The caudal fins are transparent with pale pinkish orange tint ventrally. The belly is white, and the iris is pale gold. In preservative, the body and caudal musculature is pale creamy tan. Minute dark flecks are present on the dorsal surfaces of the body. Brown flecks and reticulations are present on the caudal musculature and fins. There is a 198 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 concentration of pigment on the edges of the fins. The mouth is small, anteroventral, and has lateral folds in the lips. The median part of the upper lip is bare, and the rest of the upper lip bears a single row of moderately large papillae. Two rows of papillae are present on the lower lip, and additional papillae are pres- ent in the lateral fold. The beaks are moder- ately robust and bear small serrations. The upper beak is in the form of a broad arch with moderately long, slender lateral pro- cesses. The lower beak is V-shaped. There are two upper and three lower rows of teeth. The upper rows are equal in length and ex- tend to the labial papillae. The second upper row is narrowly interrupted medially. The first and second lower rows are equal in length and only slightly shorter than the upper rows; the third lower row is somewhat shorter. All lower rows are complete (fig. 72C). Mating Call: The mating call of Hyla staufferi staufferi consists of a series of short nasal notes, "ah-ah-ah-ah." The call groups are usually composed of two to 30 notes, but some individuals have been heard to produce 77 consecutive notes. The notes have a dura- tion of 0.13 to 0.23 of a second and a pulse rate of 100 to 130 pulses per second. The funda- mental frequency is at about 106 cycles per second. Two harmonics are emphasized with nearly equal intensity; these are at about 1743 and 3056 cvcles per second (pi. 26, fig. 2; table 17). Natural History: Hyla staufferi staufferi occurs in subhumid forests and savannas where rainfall is highly seasonal. Consequent- ly, the frog is active for only a part of the year. During the dry season, individuals have been found in the axils of the leaves of ele- phant-ear plants and in bromeliads. Breeding activity begins with the onset of rains in May and June and continues until at least Sep- tember. Breeding takes place in shallow, tempo- rary ponds. Males call from grasses, herbs, and low bushes at the edge of the pond. At some places after heavy rains, large numbers of Hyla staufferi staufferi congregate at breed- ing ponds. At these times the frogs evidently are in competition for calling sites, and the result is that some individuals call from the ground or from shallow water. Eggs are deposited in small clumps in the shallow water. The tadpoles develop in the shallow ponds, where they show a definite preference to areas containing dense grasses or aquatic vegeta- tion. The tadpoles seek refuge amidst this vegetation. One recently metamorphosed juvenile has a snout-vent length of 13.0 mm. The dorsum is dull olive-tan with no evidence of darker markings; the venter is creamy white. Remarks: Cope (1887, p. 14) considered staufferi to be a subspecies of Hyla eximia. Some other workers followed Cope who ap- parently concluded the relationship on the basis of the absence of webbing on the hand in both staufferi and eximia. Kellogg ( 1932, p. 174) concluded that staufferi and eximia were distinct species. Dunn and Emlen ( 1932, p. 24) named Hyla culex from Tela, Honduras on the basis of a single male (M.C.Z. No. 16098) and one female (U.S.N.M. No. 20267) from Patuca, Honduras. Most subsequent workers did not recognize Hyla culex. Duell- man (1966b, p. 274) and Leon (1969, p. 537) considered culex to be a synonym of Hyla staufferi. On the basis of similarities in call structure, Blair (1960, p. 129) placed Hyla staufferi in the Hyla eximia group. Granted that similarities in the structure do exist, the morphological evidence overwhelmingly sup- ports the inclusion of Hyla staufferi in the Hyla rubra group, which is only distantly re- lated to the Hyla eximia group. The proclivity of Hyla staufferi for sub- humid environments has permitted its dis- persal throughout most of northern Middle America. Extensive areas of humid lowland tropical forest apparently are barriers to this frog. In the lowland area of El Peten, Guate- mala, Hyla staufferi staufferi inhabits the open savannas, but is absent from the main forest. Etymology: The specific name staufferi obviously is a patronym. I have been unable to determine the identity of Mr. Stauffer. Distribution: Hyla staufferi staufferi in- habits savannas and subhumid forests in the lowlands to moderate elevations from south- ern Tamaulipas, Mexico, southward to Nica- ragua on the Caribbean versant and from Guerrero, Mexico to northwestern Costa Rica 1970 DUELLMAN: HYLID FROGS 199 on the Pacific (fig. 77). In parts of northern- central America, the range apparently is dis- continuous. The subspecies occurs in islands of savannas surrounded by rain forests in northern Guatemala; it occurs in subhumid valleys in Guatemala and Honduras. See Appendix 1 for the locality records of the 1973 specimens examined. Hyla staufferi altae Dunn Hijla altae Dunn, 1933, p. 61 [holotype, M.C.Z. No. 17972 from Summit, Canal Zone, Panama; Em- mett R. Dunn collector]. Hyla staufferi (part): Taylor, 1952c, p. 862. Duellman, 1966b, p. 274. Hyla staufferi altae: Leon, 1969, p. 540. Diagnosis: Hyla staufferi altae differs from all other Middle American hylids by having an acuminate, protruding snout, vestigial web- bing on the hands, no transverse bars on the shanks, and a dorsal pattern consisting of a dark triangular interorbital mark and com- plete longitudinal dark stripes. The nominate subspecies differs by having incomplete longi- tudinal marks on the dorsum and transverse bars on the shanks. Hyla elaeochroa differs by being larger and in having an irregular dorsal pattern, and H. rubra differs by having dark brown or black reticulations enclosing yellow spots on the posterior surfaces of the thighs. Description: Males of this small subspe- cies attain a maximum snout-vent length of 26.0 mm., and females reach 27.8 mm. In a series of 29 males from the Pacific lowlands between the Canal Zone and Chepo, Panama, the snout-vent length is 22.2 to 25.8 (mean, 23.5) mm.; the ratio of tibia length to snout- vent length is 0.413 to 0.472 (mean, 0.444); the ratio of foot length to snout-vent length is 0.352 to 0.399 (mean, 0.380); the ratio of head length to snout-vent length is 0.313 to 0.341 (mean, 0.327); the ratio of head width to snout-vent length is 0.262 to 0.302 (mean, 0.279), and the ratio of the diameter of the tympanum to that of the eye is 0.498 to 0.583 ( mean, 0.527 ) . Three females from the same area have snout-vent lengths of 26.8 to 27.8 (mean, 27.1) mm. They show no significant differences in proportions from the males. Comparison of these specimens from central Panama with specimens from western Pan- ama reveal that the latter are slightly larger and have slightly longer legs and larger tym- pani ( table 21 ) . Structurally, Hyla staufferi altae is like the nominate subspecies; the reader is referred to the account of Hyla staufferi staufferi for a detailed description. The only noticeable structural difference is in the amount of web- bing on the foot. In H. s. altae the toes are slightly more than one-half webbed. Webbing is vestigial between the first and second and between the second and third toes. The web extends from the base of the penultimate pha- lanx of the third to the base of the antepenulti- mate phalanx of the fourth and from the mid- dle of the antepenultimate phalanx of the fourth to the middle of the penultimate pha- lanx of the fifth toe. The general coloration of Hyla staufferi altae at night is yellowish or olive-tan with brown longitudinal markings (pi. 47, fig. 3). By day, the frogs are grayish tan or olive-gray with brown markings. The posterior surfaces of the thighs are colored like the dorsum. The venter is white; the vocal sac in breeding males is yellow. A pair of distinct, usually complete, dark brown dorsolateral stripes and a pair of entire paravetebral stripes are in- variably present. In some specimens, a nar- row vetebral stripe is present. A longitudinal dark brown stripe is present on the dorsal surface of the shank. A faint interorbital spot or transverse bar is present in some specimens. The iris is dull bronze with dark brown suf- fusion and reticulations. In preservative, the dorsum is tan or gray- ish brown with dark brown markings. The ventral surfaces are creamy tan. Tadpoles: The size and structure of the tadpoles of Hyla staufferi altae are like those of the nominate subspecies. The coloration is somewhat paler. In life the dorsum is tan, and the venter is a pale golden white. The caudal musculature is pale creamy tan, and the caudal fins are transparent. Minute dark brown or black flecks are present on the tail. The iris is pale bronze. Mating Call: The call of Hyla staufferi altae is like that of the nominate subspecies, except the notes are slightly shorter and that the lower emphasized harmonic is at a point 200 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 about 300 cycles per second higher than in the nominate subspecies (table 17). Natural History: This subspecies oc- curs in xeric, scrubby forests and in savannas. The breeding season coincides with the rains, which usually begin in May and last until October. Males call from grasses and herbs in or at the edge of temporary ponds. The tadpoles have been found in shallow grassy ponds, where they seek refuge among the vegetation. Remarks: Taylor (1952c, p. 863) and Duellman (1966b, p. 274) did not recognize altae. Roth of these workers considered Hijla staufferi to be monotypic. Leon ( 1969, p. 533) demonstrated the minor structural differences between Panamanian and more northern pop- ulations of Hyla staufferi, and he pointed out the distinctive color pattern of the Panama- nian population. At the present time, no specimens representing an intergradirig be- tween the subspecies are available. Slight clinal variation in size and certain proportions is evident throughout the range of the species ( table 21 ) . The distinctive break in coloration occurs at a hiatus in the distribution, namely the humid Golfo Dulce in southeastern Costa Rica, where Hyla staufferi does not occur. Etymology: The subspecific name is a patronym for Alta Merle Dunn. Distribution: Hyla staufferi altae occurs on the subhumid Pacific lowlands of Panama from Concepcion, Chiriqui Province, to Chepo in the lower Rayano valley, Panama Province (fig. 77). See Appendix 1 for the locality records of the 154 specimens examined. Hyla boulengeri (Cope) Scytopis boulengeri Cope, 1887, p. 12 [holotype, U.S.N. M. No. 13974 from "Nicaragua"; J. A. McNiel collector]. Hyla boulengeri: Giinther, 1901 ( 1885-1902 ), p. 267. Taylor, 1952c, p. 856. Leon, 1969, p. 511. Diagnosis: Hyla boulengeri is a medium- sized species having an acuminate snout, tu- berculate dorsum, no webbing on the hand, and a bold contrasting pattern of black and yellow or green vertical bars on the thighs. The only Middle American hylid with which it can be confused is Hyla rostrata, which has a more pointed snout, smooth dorsum, vesti- gial webbing on the hand, a creamy white groin and a brown or gray vocal sac. Hyla boulengeri usually has a dark spot in the groin and a white vocal sac. Furthermore, the pale bars on the thighs in rostrata are pale orange in life. The only other Middle Ameri- can hylid having black and yellow vertical bars on the thighs in Hyla lancasteri, which has a short, truncate snout and webbing be- tween the fingers. The long unwebbed fingers and truncate discs of Hyla boulengeri are like those of many species of Eleutherodactylus. Description: This is the largest Middle American species in the Hyla rubra group. Males attain a maximum snout-vent length of 48.7 mm., and females reach 52.8 mm. In a series of 25 males from Puerto Viejo, Heredia Province, Costa Rica, the snout-vent length is 37.5 to 42.9 (mean, 41.6) mm.; the ratio of tibia length to snout-vent length is 0.512 to 0.620 (mean, 0.552); the ratio of foot length to snout-vent length is 0.380 to 0.462 (mean, 0.431 ) ; the ratio of head length to snout-vent length is 0.361 to 0.412 (mean, 0.383); the ratio of head width to snout-vent length is 0.314 to 0.359 (mean, 0.341), and the ratio of the diameter of the tympanum to that of the eye is 0.630 to 0.789 (mean, 0.713). Eight females from the same locality have snout-vent lengths of 44.8 to 52.8 (mean, 49.4) mm. The ratio of the diameter of the tympanum to that of the eye is 0.708 to 0.800 (mean, 0.769); no other sexual dimorphism in proportions is evi- dent. No noticeable geographic variation in size and proportion occurs in Middle America; however, specimens currently assigned to Hyla boulengeri from the Pacific lowlands of north- western South America are noticeably smaller. The head is longer than wide; the top of the head is slightly convex. In lateral and dor- sal profiles, the snout is acuminate; the tip of the snout projects beyond the leading edge of the lower jaw. The snout is long; the nos- trils are greatly protuberant, directed dorso- lateral^, and situated just above the leading edge of the lower jaw at a point about four- fifths from the eyes to the tip of the snout. The canthus is rounded and barely distinct; the loreal region is flat and inclined laterally. The lips are flared. A thin dermal fold extends 1970 DUELLMAN: HYLID FROGS 201 posteriorly from the posterior edge of the eye, above the tympanum, and thence downward to a point above the insertion of the arm. The fold obscures the upper edge of the tympa- num, which otherwise is distinct. The tym- panum is posteroventral to the eye and sepa- rated from the eye by a distance slightly less than the diameter of the tympanum. The arm is moderately long and slender; no axillary membrane is present. There are no tubercles forming a row along the ventro- lateral edge of the forearm, nor is a transverse fold present on the wrist. The fingers are long and slender and bear large truncate discs; the width of the disc on the third finger is about equal to the diameter of the tympanum. Narrow dermal fringes are present on the edges of the digits. The subarticular tubercles are large and round; none is bifid. Small, conical supernumerary tubercles are present on the proximal segments of each digit. The palmar tubercle is large, flat, and tripartite. An elongate, flat, tubercle is present on the prepollex, which is barely enlarged and does not bear nuptial excrescences in breeding males. Webbing is absent between the fingers (fig. 6SD). The hindlimbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation ex- tends to a point between the eye and the nostril. One or two tubercles and a thin trans- verse dermal fold are present on the heel. A weak tarsal fold is present. The inner meta- tarsal tubercle is low, flat, round, and not visible from above. The outer metatarsal tu- bercle, if present, is small and conical. The toes are long and slender and bear discs that are truncate and nearly as large as those on the fingers. The subarticular tubercles are large and round; the supernumerary tubercles are small, round, and arranged in a single row on the proximal segment of each digit. The toes are about three-fourths webbed (fig. 69D). The webbing exists as a fringe on the medial side of the first toe and the lateral edge of the second toe; the webbing extends from the base of the disc of the second to the base of the penultimate phalanx of the third; from the base of the disc of the third to the base of the penultimate phalanx of the fourth and on to the base of the fifth toe. The anal opening is directed posteroven- trally at a level at the middle of the thighs. The anal sheath is short and broad. The skin on the belly and proximal posteroventral sur- faces of the thighs is granular; that on the ventral surfaces of the limbs is smooth. On all of the dorsal surfaces, the skin bears small tubercles. The tongue is narrowly cordiform, shallowly notched behind, and barely free pos- teriorly. The dentigerous processes of the prevomers are closely approximated trans- verse ridges between the middle of the elon- gate, elliptical, large, choanae. In the series of males from Puerto Viejo, three to 10 teeth are present on each process, and a total num- ber of prevomerine teeth is eight to 17 ( mean, 13.0). In the eight females six to 10 teeth are present on each process, and the total number of prevomerine teeth is 12 to 19 ( mean, 15.2 ) . The vocal slits extend from the midlateral base of the tongue to the angle of the jaw. The vocal sac is single, median, sub- gular, and moderately distensible. In some specimens, the dark colored inter- orbital triangular mark is bordered by a row of tubercles. Also, rugosities are present on the tip of the snout, edge of the eyelid, edge of the lower jaw, and ventrolateral edges of the forearm and tarsus in some specimens. Individuals from the Caribbean lowlands of Central America generally are less tuberculate than those from the Golfo Dulce region in Costa Rica. The general coloration of Hyla boulengeri is grayish tan or a dull green with darker dorsal markings (pi. 48, figs. 1 and 2). Indi- viduals from Puerto Viejo, Heredia Province, Costa Rica, when calling at night were gray- ish tan with slightly darker dorsal markings. The flash colors on the flanks are a pale yel- lowish green. Ry day, the dorsum was brown or tan with dark brown markings. The venter is creamy white; gray flecks were present on the throat. The groin was pale green with black spots or mottling. The anterior and pos- terior surfaces of the thighs and the inner edges of the tarsi were greenish yellow to orange-yellow with black bars. The iris was dull bronze. The dorsal markings normally consist of a dark interorbital triangular mark and two or more large dark blotches on the dorsum. Three or four transverse brown bars 202 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 are present on the dorsal surfaces of the thighs; two or three bars are present each on the shank, foot, and forearm. The anterior and posterior surfaces of the thighs have long, vertical black bars, separated by pale green, yellowish green, or yellow-orange interspaces. Short bars are present on the inner surfaces of the feet; these likewise are separated by pale green or yellow interspaces. The groin is pale yellow, greenish yellow, or cream- colored. The groin is variously marked by black mottling, one large black spot, or two or three smaller black spots. In preservative the dorsum is dull brown with darker brown markings. The interorbital triangle is apparent. The anterior and pos- terior surfaces of the thighs and the intersur- faces of the tarsi are creamy white with black bars. The venter is pale cream; brown flecks are present on the throat. Tadpoles: A small series of tadpoles in later developmental stages is available; the sizes of these specimens were discussed by Leon (1969, p. 516). A tadpole in develop- mental stage 30 had a body length of 11.0 mm. and a total length of 33.2 mm. The largest individuals are in developmental stage 42; one such tadpole has a body length of 13.0 and a total length of 34.0 mm. A typical tad- pole in developmental stage 38 has a body length of 11.5 mm. and a total length of 33.5 mm. The body is slightly deeper than wide. The snout is bluntly rounded in dorsal profile and inclined anteroventrally, but rounded terminally, in lateral profile. The nostrils are small, directed anterolateral!}', and slightly closer to the eyes than to the tip of the snout. The eyes are moderately large and directed laterally. The spiracle is sinistral; its opening is directed posteriorly at a point below the midline and about two thirds the distance from the snout to the posterior edge of the body. The cloacal tube is short and dextral. The caudal musculature is moderately shal- low and gradually tapers posteriorly. The caudal fins are deep; at midlength of the tail the caudal musculature is shallower than either the dorsal or ventral fin. The dorsal fin ex- tends onto the body nearly to the posterior edge of the eye; both fins are deepest just anterior to the midlength of the tail and both taper rather sharply to a terminal point (fig. 71D). In life the body is silvery yellow; the caudal musculature is pale cream, and the fins are transparent. The tail is marked by large, closely spaced black spots on the middle two- thirds of its length. In preservative, the tad- poles lack pigment except for the spots on the tail. The mouth is small and anteroventral in position. Shallow lateral folds are present in the lips. The lips lack papillae, except later- ally, where there is a single row of large, blunt papillae. Medial to these, in the lateral fold, there are numerous, small conical pa- pillae. The beaks are massive and bear long pointed serrations. The upper beak forms a narrow arch with moderately long lateral pro- cesses. The lower beak is shallowly V-shaped. There are two upper and three lower rows of teeth. The upper rows are equal in length and extend to the lip. In all specimens, the second upper row is narrowly interrupted medially, whereas the first upper row usually is complete. The first and second lower rows are about equal in length, usually complete, and much shorter than the upper rows. The third lower row is very short and gives the appearance of being a modified part of the lower lip. The teeth are long, slender, and curved; they are especially large in the third lower row (fig. 72D). Mating Call: The call of Hyla boulengeri consists of a single, low-pitched note, which might be described as a low "growl." Notes are repeated at intervals of 10 seconds to sev- eral minutes. The notes have a duration of 0.24 to 0.47 of a second and a pulse rate of 80 to 120 pulses per second. The fundamental frequency is at about 71 cycles per second. Two harmonics are emphasized with nearly equal intensity; these are at about 1600 and 2800 cycles per second (table 17; pi. 27, fig. 2) . Natural History: This species inhabits humid, lowland tropical forests with rainfall rather equally distributed throughout the year, consequently, the frogs are active throughout most of the year. The breeding season appar- ently is lengthy, because calling males have been heard in every month from January through November. Males call from secluded 1970 DUELLMAN: HYLID FROGS 203 positions. Normal calling sites include stumps or logs that are covered with broad-leafed vegetation, under which the frogs perch. Other individuals have been found calling from dense bushes, or depressions in logs or stumps in and at the edge of ponds. Amplexus takes place out of the water. Eggs are de- posited in shallow water. No information is available concerning early developmental stages of the tadpoles, but tadpoles in ad- vanced stages of development were found in a temporary pond at Rincon de Osa, Punta- renas Province, Costa Rica. A recently metamorphosed young from Rincon de Osa, Puntarenas Province, Costa Rica, has a snout-vent length of 15.0 mm. The head is as long as wide, and the eyes are prom- inent. The limbs are weakly barred, and the skin is rugose above and granular below. The dorsum and limbs are pale green (change to gray-brown in preservative), and the venter is white. The interorbital space, supratym- panic fold, and scapular region are darker than the rest of the body. The fingers lack webs, and the webbing on the foot is the same as in the adults. Small metatarsal tu- bercles are present, but the tarsal fold is ab- sent. Remarks: Dunn and Emlen (1932, p. 25) placed Hyla lancasteri Barbour in the synon- ymy of Hyla boulengeri. Taylor (1952c) fol- lowed Dunn and Emlen with reservation and described Hyla moraviaensis from eastern Costa Rica. Duellman ( 1966b, p. 271 ) showed that Hyla lancasteri was not the same as Hyla boulengeri and that Hyla moraviaensis was a synonym of Hyla lancasteri. Etymology: The specific name is a pat- ronym for the famous Nineteenth Century herpetologist George Albert Boulenger. Distribution: In Central America, Hyla boulengeri occurs on the Caribbean lowlands from central Nicaragua to South America where it ranges on the Pacific lowlands to northwestern Ecuador. This species also oc- curs in locally humid areas in Guanacaste Province, and in the humid Golfo Dulce region of Costa Rica (fig. 78). Hyla boulengeri has 78° 12' IOc Fig. 78. Distribution ot Hyla boulengeri. 204 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 been found at elevations of 620 meters at Turrialba, Cartago Province, and at 700 me- ters at Tilaran, Guanacaste Province, Costa Rica. See Appendix 1 for the locality records of the 178 specimens examined. Hyla rostrata Peters Htjla rostrata Peters, 1863, p. 466 [holotype, Z.M.B. No. 3175 from Caracas, Venezuela; Golmer collector]. Rivero, 1968, p. 133. Hyla foliamorta Fouquette, 1958, p. 125 [holo- type, T.N.H.C. No. 23109 from 11 kilometers north of Miraflores Locks, Canal Zone, Panama; M. J. Fou- quette, Jr. collector]. Leon, 1969, p. 520. Diagnosis: Hyla rostrata is a medium- sized species having an acuminate and pro- truding snout, smooth dorsum, vestigial web- bing on the hand, a dark gray or brown vocal sac, and orange and black bars on the thighs. This species resembles H. bonlengeri, which lacks webbing on the hand and has a tubercu- late dorsum, white vocal sac, and black and yellow or green bars on the thighs. Hyla ro- strata can be confused with no other Middle American hylids. Description: This is a moderately large member of the Hyla rubra group. Males attain a maximum snout-vent length of 45.7 mm. The one female from Central America has a snout-vent length of 41.0 mm. In a series of 28 males from an area between Tocumen and Chepo, Panama Province, Panama, the snout- vent length is 40.0 to 45.7 (mean, 42.5) mm.; the ratio of tibia length to snout-vent length is 0.541 to 0.609 (mean, 0.572); the ratio of foot length to snout-vent length is 0.403 to 0.461 (mean, 0.432); the ratio of head length to snout- vent length is 0.352 to 0.397 (mean, 0.371); the ratio of head width to snout-vent length is 0.302 to 0.354 (mean, 0.323), and the ratio of the diameter of the tympanum to that of the eye is 0.563 to 0.811 (mean, 0.672). The head is as wide as the body and some- what longer than wide. The snout is acumi- nate in dorsal and lateral profiles; in lateral profile, the snout projects well beyond the leading edge of the lower jaw. The snout is long; the nostrils are protuberant, directed dorsolaterally, and situated at about four- fifths the distance from the eyes to the tip of the snout, slightly anterior to the leading edge of the lower jaw. The canthus is rounded and barely discernible; the loreal region is flat and inclined laterally and confluent with the slightly flared lips. A moderately heavy der- mal fold extends from the eye above the tym- panum and thence downward to a point above the insertion of the arm. The fold barely ob- scures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance equal to the diameter of the tympanum. The arms are moderately long and slender; there is no axillary membrane. Tubercles are absent from the outer edge of the forearm, and there is no transverse fold on the wrist. The fingers are long and slender and bear large truncate discs; the width of the disc on the third finger is greater than the diameter of the tympanum. The subarticular tubercles are very large and round. The supernumerary tu- bercles are low, indistinct, and irregular in position. The palmar tubercle is low and flat basally and higher and bifid distally. A low, ovoid tubercle is present on the prepollex, which is barely enlarged, and in breeding males does not bear a nuptial excrescence. A vestige of a web exists between the fingers ( fig. 68E ) . The legs are moderately long and slender; the heels of the adpressed limbs over- lap by about one-third of the length of the shank. The tibiotarsal articulation extends to the nostril. A heavy transverse dermal fold is present on the heel, but a tarsal fold is ab- sent. The inner metatarsal tubercle is small, ovoid, subcorneal, and not visible from above. The outer metatarsal tubercle is slightly smaller and conical. The toes are long and slender and bear discs that are somewhat smaller than those on the hands. The sub- articular tubercles are large and round, and the supernumerary tubercles are small, sub- conical, and arranged in a single row on the proximal segments of each digit. The toes are about three-fourths webbed (fig. 69E). The webbing is vestigial between the first and second toes, except for a fringe on the lateral edge of the second toe; the webbing extends from the base of the disc of the second to the base of the penultimate phalanx of the third, from the base of the disc of the third to the base of the penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. 1970 DUELLMAN: HYLID FROGS 205 The anal opening is directed posteroven- trally near the level of the upper edges of the thighs; a short anal sheath is present. The skin on the belly and proximal posteroventral surfaces of the thighs is granular; elsewhere the skin is smooth. The tongue is cordiform, moderately notched behind but barely free posteriorly. The dentigerous processes of the prevomers are transverse between the moder- ately large, elongately elliptical choanae. There are four to nine teeth on each process; the total number of prevomerine teeth is nine to 15 (mean, 11.2). The vocal slits extend from the midlateral base of the tongue to the angle of the jaw. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla rostrata is gray or tan with darker dorsal markings (pi. 48, fig. 3). The dorsal ground color is pale tan to grayish tan or reddish tan with darker brown markings. The markings consist of a distinctive interorbital bar, usually triangular in shape with the apex directed posteriorly. The rest of the dorsum is marked by two ir- regular blotches or broad reticulations. In some individuals, the dark marks are narrowly outlined by pale gray. Narrow transverse bars are present on the dorsal surfaces of the limbs. The groin is creamy white without dark spots or mottling. The anterior and posterior sur- faces of the thighs are yellow or orange with black or dark brown markings. Usually these markings are in the form of broad, vertical bars, but in some individuals the bars are in- terconnected or have a pale center. The belly is white, and the vocal sac is dark gray or brown. The iris is pale bronze. In preservative, the dorsum is pale gray or pale brown with darker gray or brown markings, which in most specimens are nar- rowly outlined with creamy tan. The anterior and posterior surfaces of the thighs are creamy white with dark brown markings. The venter is creamy white except for the throat which is grayish brown. Tadpoles: A typical tadpole in develop- mental stage 34 had a body length of 9.5 mm. and a total length of 34.5 mm. The body is slightly deeper than wide. In dorsal profile the snout is bluntly rounded; in lateral profile the snout slopes acutely from the nostrils to terminate in a truncate tip. The nostrils are protuberant and about midway between the eyes and the tip of the snout. The eyes are moderately large and directed laterally. The sinistral spiracle has its opening directed pos- teriorly below the midline at a point about two-thirds of the distance from the snout to the posterior edge of the body. The anal tube is short and dextral. The caudal musculature is relatively shallow and is finely tapered pos- teriorly. At midlength of the tail, the depth of the musculature is equal to about two- thirds of either the depth of the dorsal or the ventral fin. The dorsal fin extends well onto the body, nearly to the posterior edge of the eye, and terminates distally in a narrow fringe along the musculature. The ventral fin has an equal depth throughout the anterior half of the tail and then diminishes to a narrow fringe along the musculature, thereby result- ing in a xiphicercal tail (fig. 71E). In life the body and tail are pale greenish yellow with black spots; the iris is pale gold. In preservative, the dorsal part of the body and the snout anterior to the eyes is dark brown. The rest of the body lacks pigment, except for a few small flecks below the eye. The caudal musculature is creamy white and the fins are transparent. Both are marked by spots of large pigment, larger spots made up of smaller pigment, and dark reticulations. The mouth is small and anteroventral. The lips have a shallow lateral fold. The median part of the upper lip is bare, and the rest of the lips are bordered by a single row of mod- erately large, blunt papillae. Additional small papillae are present in the lateral fold. The beaks are robust and bear moderately long serrations. The upper beak forms a broad arch with long, slender lateral processes; the lower beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows are about equal in length and ex- tend nearly to the lips; the second upper row is narrowly interrupted medially. The lower rows are shorter than the upper rows and the third row is the shortest. In some specimens, the first lower row is narrowly interrupted medially. The teeth are not exceptionally long nor are they curved. The longest teeth are in the first upper row (fig. 72E). Mating Call: The call of Hyla rostrata is a single, low-pitched note. The call repe- 206 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 tition rate varies from about 20 seconds to several minutes. The duration of the note is from 0.23 to 0.86 of a second, and the pulse rate is 50 to 60 pulses per second. The funda- mental frequency is at about 56 cycles per second. Two harmonics are emphasized with nearly equal intensity; one of these is at about 920 cycles per second, and the other is at about 3055 cycles per second ( table 17; pi. 27, fig. 3). Natural History: Hyla rostrata inhabits subhumid, scrubby forest and savannas, which have a relatively short rainy season usually extending from May to September. This spe- cies breeds in temporary ponds in the savan- nas and scrub forests. Fouquette (1958, p. 128) stated that males call from "about four to seven feet above the ground in tall cane grasses or small ponds." In the area between Tocumen and Chepo, Panama Province, Pan- ama, this species has been observed to call from low, dense, sometimes thorny, bushes in and at the edge of temporary ponds. The tad- poles were found in a weedy temporary pond; the tadpoles sought refuge in the vegetation. On the Pacific side of the Canal Zone, Hyla rostrata occurs sympatrically with Hyla boulengeri, which, according to Fouquette ( 1958, p. 128 ) calls from lower sites. Through- out most of the range of rostrata, boulengeri is absent. Apparently Hyla rostrata replaces boulengeri in the more xeric habitats. Remarks: Fouquette (1958) recognized this species as distinct from boulengeri in Pan- 79° 78° Fig. 79. Distribution of Hyla rostrata. 1970 DUELLMAN: HYLID FROGS 207 ama and named Hyla foliamorta. Rivero (1968) showed that Hyla rostrata Peters was the earliest available name for the species. Etymology: The specific name is derived from the Latin rostrum meaning muzzle and refers to the prominent snout. Distribution.- Hyla rostrata occurs in sub- humid habitats from central Panama eastward to northern Colombia, northern Venezuela, and the Guianas (fig. 79). See Appendix 1 for the locality records of the 50 specimens examined. The Hyla microcephala Group Definition: The members of this group are small species; males attain a maximum snout-vent length of 27 mm. and females, 32 mm. The dorsum is yellowish tan with brown markings; the thighs are uniformly yellow. The palpebral membrane is clear. The fingers are about one-third, and the toes about three- fourths webbed. Dermal folds and append- ages are lacking on the limbs, but a distinct axillary membrane is present. Males have single, median, subgular vocal sacs, but lack nuptial excrescences on the pollices. The cranial elements are reduced in ossification; a large frontoparietal fontanelle is present, and the quadratojugal is much reduced and not in contact with the maxillary. Prevomerine teeth are present. The tadpoles have xiphicer- cal tails and a terminal mouth lacking teeth and labial papillae. The mating call consists of a primary note followed by a series of sec- ondary notes. The haploid number of chromo- somes is 15 (known only in H. microcephala and phlebodes) . Composition: Four species (H. micro- cephala, phlebodes, robertmertensi, and sar- tori) occur in Middle America. South Ameri- can relatives include several species (H. elon- gata, minuta, nana, and werneri) widely dis- tributed east of the Andes. Fouquette ( 1968) indicated that the South American H. misera is a subspecies of H. microcephala. Two sub- species of Hyla microcephala are recognized in Middle America; the other species are mon- otypic. Of the five species, 2948 preserved frogs, 37 skeletons, nine lots of tadpoles, and four preserved clutches of eggs were examined from Middle America. Comments: The members of the Hyla microcephala group exhibit few differences in size or proportions; minor differences exist in the structure of the hands and feet (figs. 80 and 81). The known tadpoles can be dis- tinguished only by their coloration (fig. 82), for in size and shape they show few differ- ences; all have greatly reduced, terminal mouths (fig. 83). The coloration and mating calls provide the easiest means of identifica- tion of the species (pis. 28, 29, and 49). The mating calls are an insect-like series of notes, "creek-eek-eek-eek," composed of a primary note followed by a series of shorter secondary notes. The primary note of Hyla microcephala is unpaired, and the secondary notes are paired, whereas the opposite is true of robertmertensi. All notes are unpaired in phlebodes and sartori; also, the dominant fre- quencies are much lower in these species than in robertmertensi and microcephala (table 22). Duellman and Fouquette (1968) ana- lyzed the mating calls of the species in this group and, among other things, showed that the only sympatric species ( microcephala and phlebodes) had the most divergent calls. Osteologically, this group of species is characterized by a minimal amount of cranial ossification. Despite the little ossification, cer- tain cranial differences are apparent among the species. Differences in the amount of ossi- fication of the frontoparietals and the conse- quent shape and size of the frontoparietal fon- tanelle result in H. microcephala having mini- mally ossified frontoparietals with a large fontanelle, whereas the ossification is more extensive anteriorly in the other species, there- by producing a fontanelle that is widest pos- teriorly in phlebodes and robertmertensi and one that is of nearly uniform width throughout its length in sartori (fig. 84). In H. micro- cephala the nasals are long, slender, and ar- cuate in dorsal view. The nasals are broader in sartori, and they are wider anteriorly than posteriorly in phlebodes and robertmertensi. The sphenethmoid is extremely short in H. microcephala and moderately short in the other species. The sphenethmoid is ossified anteriorly between the nasals in sartori. The distal end of the columella is expanded in H. microcephala, slightly expanded in some rob- 208 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 80. Hands of the species in the Hyla microcepliala group. A. H. microcepliala, K.U. No. 101606. B. H. robertmertensi, K.U. No. 57618. C. H. phlebodes, K.U. No. 77270. D. H. sartori, K.U. No. 67855. X 8. ertmertensi, and not expanded in the other species. The osteological similarities are strongly suggestive of close relationships among the species in the Hyla microcepliala group. However, the trivial differences among the species provide little evidence for deter- mining phylogenetic lineages. Duellman and Fouquette ( 1968) suggested that the Hyla microcepliala group was first represented in Middle America by a micro- cephala-Mke ancestral stock which emigrated from South America. Their phylogenetic sup- positions include an early divergence into a phlebodes-like frog on the Caribbean low- lands of Central America and a microcephala- like frog on the Pacific lowlands; the former gave rise to phlebodes and sartori, and the latter evolved into microcepliala and robert- mertensi. No new evidence has come to light that disproves this hypothesis. The Hyla microcepliala group occurs at low elevations from Jalisco and Veracruz, 1970 DUELLMAN: HYLID FROGS 209 Fie. 81. Feet of the species in the Hyla microcephala group. A. H. microceplwla, K.U. No. 101606. B. H. robertmertensi, K.U. No. 57618. C. H. phlebodes, K.U. No. 77270. D. H. sartori, K.U. No. 67855. x 8. 210 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 82. Tadpoles of the Hyla microcephala group. A. H. microcephala micro- cephala, K.U. No. 104097. B. H. microcephala underwoodi, K.U. No. 106935. C. H. phlebodcs, K.U. No. 104099. x 4. Mexico, southeastward into South America. Members of this group are among the most common and conspicuous (by their voices) frogs in the lowlands of Middle America. Hyla microcephala Cope Hyla microcephala Cope, 1886, p. 281. Diagnosis: This small species is distin- guished from other Middle American Hyla with uniformly yellow thighs by having a nar- row lateral brown stripe extending to the sac- ral region or to the groin and bordered above by a narrow white line. The dorsum is marked by a pair of discreet longitudinal dark lines, interconnecting dark lines, or variously ar- ranged dashes. The head is narrow, and the axillary membrane is not well developed. See the diagnoses and descriptions of the subspe- cies for further characteristics and compari- sons. Content: Three subspecies are recog- nized: Hyla m. microcephala Cope inhabits the Pacific lowlands of southeastern Costa Rica eastward to Colombia, //. m. misera oc- curs in northern South America and the Ama- zon Basin, and H. m. underwoodi Boulenger ranges from northwestern Costa Rica to Mex- ico. Although minor differences exist in some measurements and proportions and in certain parameters of the mating calls, the color pat- tern provides the major, and only diagnostic, differences between the subspecies. The east- ern subspecies (H. m. microcephala) char- acteristically has a dorsal pattern of two con- tinuous dark lines and no interorbital dark Fig. 83. Mouth of a tadpole of Hyla microcephala microcephala, K.U. No. 104097. x 48. 1970 DUELLMAN: HYLID FROGS 211 TABLE 22 Characteristics of the Mating Calls, with Means in Parentheses, of Frogs in the Hyla microcephala Group. Species N H. m. microcephala 44 II. m. underwoodi 47 H. robertmertensi .. 25 H. phlebodes 34 H. sartori .___ 10 Duration of Primary Note (seconds) Repetition Rate of Secondaries (notes per minute) Fundamental Frequency (cps) Dominant Frequency (cps) 0.11-0.16 192-353 184-244 5150-5962 (0.13) (268) (205) (5637) 0.05-0.15 197-384 192-275 5177-6200 (0.11) (268) (220) (5772) 0.07-0.11 368-570 140-178 5150-5785 (0.09) (418) (162) (5388) 0.07-0.16 210-350 125-158 3220-4067 (0.11) (284) (148) (3578) 0.07-0.09 396-477 116-135 2950-3600 (0.08) (434) (126) (3217) mark, whereas the northwestern subspecies (H. m. underwoodi) has a variegated dorsal pattern and usually has a dark interorbital mark. Also, the shanks in H. in. microcephala are marked with flecks or a longitudinal line, never the narrow transverse bands usually found in H. in. underwoodi. Distribution: Hyla microcephala occurs in the foothills and at low elevations on the Atlantic lowlands from southern Veracruz and northern Oaxaca, Mexico, southeastward to north-central Nicaragua and thence southeast- ward on the Pacific lowlands to eastern Pan- ama (fig. 85). The species occurs in the Mag- dalena and Cauca valleys (Caribbean drain- age) of Colombia, in northern South Amer- ica and discontinuously in the Amazon Basin. Hyla microcephala microcephala Cope Hyla microcephala Cope, 1886, p. 281 [syntypes, U.S.N.M. No. 13473 (two specimens, now lost) from Chiriqui, Panama; J. A. McNeil collector], Giinther, 1901 (1885-1902), p. 265. Hyla microcephala microcephala: Smith, 1951, p. 185 [first usage of trinomial]. Duellman and Fou- quette, 1968, p. 526. Diagnosis: Hyla in. microcephala can be distinguished from other small Middle Ameri- can Hyla with uniformly yellow thighs by the presence of a narrow dark brown lateral stripe extending from the nostril along the canthus and the upper edge of the tympanum to the groin, bordered above by a narrow white line, yellowish tan dorsum with a pair of longi- tudinal dark brown lines extending to the Fig. 84. Dorsal views of the skulls of two species of the Hyla microcephala group. No. 68293. B. H. phlebodes, K.U. No. 68303. x 8. A. H. microcephala, K.U. 212 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 o H m microcephala 3 H m microcephala x underwood/ • H m underwoodi 18' 0 100 300 ill i i KILOMETERS Fig. 85. Distribution of the subspecies of Hyla microcephala. vent, shanks with dark flecks or longitudinal line, and by the absence of a dark interorbital mark. Hyla m. undencoodi differs by having irregular marks or interconnected lines on the dorsum and usually by having a dark inter- orbital mark and dark transverse bars on the shanks. The pattern of Hyla robertmertensi resembles that of H. microcephala, but the former has a much broader lateral brown stripe which includes the loreal region and the entire tympanum. Description: This is a small slender frog; males attain a maximum snout-vent length of 24.5 mm. (mean, 25 specimens from Golfito, Costa Rica, 22.4 mm.), and females reach 30.9 (mean, nine specimens, 27.9 mm.). In a sample of 25 males from Golfito, Puntarenas Province, Costa Rica, the ratio of tibia length to snout-vent length is 0.491 to 0.544 (mean, 0.516); the ratio of foot length to snout- vent length is 0.418 to 0.480 (mean, 0.451); the ratio of head length to snout-vent length is 0.302 to 0.355 (mean, 0.331); the ratio of head width to snout-vent length is 0.290 to 0.327 (mean, 0.308), and the ratio of the diameter of the tympanum to that of the eye is 0.400 to 0.578' (mean, 0.484). Specimens from the eastern part of the range have pro- portionately shorter heads; in a sample of 25 males from 8-14 kilometers north of Mira- flores Locks, Canal Zone, the ratio of head length to snout-vent length is 0.285 to 0.328 (mean, 0.310). The head is no wider than the body, and the top of the head is flat or slightly convex. In dorsal profile the snout is acutely rounded; in lateral profile the snout is truncate, but rounded above. The snout is short; the nos- trils are slightly protuberant and situated about two-thirds the distance from the eyes 1970 DUELLMAN: HYLID FROGS 213 to the tip of the snout. The canthus is rounded and indistinct; the loreal region is barely eon- cave, and the lips are thin and barely flared. A thin dermal fold extends posteriorly from the posterior corner of the eye to a point above the insertion of the arm; the fold obscures the upper edge of the tympanum, which otherwise is distinct. The tympanum is posterior and slightly ventral to the midline of the eye and separated from the eye by a distance equal to about two-thirds the diameter of the tym- panum. The arm is short and moderately robust; an abbreviated axillary membrane is present. Dermal folds along the outer edge of the fore- arm and across the wrist are absent. The fin- gers are short and broad and have large discs; the diameter of the disc on the third finger is about three-fourths the diameter of the tympanum. The subarticular tubercles are large and round; the distal tubercles on the third and fourth fingers are bifid in about 60 per cent of the specimens. The supernumerary tubercles are large, conical, and in a single row on the proximal segments of each finger. The prepollex is moderately enlarged; breed- ing males lack a horny nuptial excrescence. The fingers are about one-third webbed (fig. 80A ) . The webbing is barely evident between the first two fingers but connects the middle of the penultimate phalanx of the second finger to the base of the antepenultimate pha- lanx of the third finger. The web extends be- tween the bases of the penultimate phalanges of the third and fourth fingers. The hind limbs are moderately short and heavy; the adpressed heels overlap by about one-fourth the length of the shank. The tibiotarsal articu- lation extends to the anterior corner of the eye. A weak tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is low, flat, and elongate. The toes are moderately long and slender; the discs are slightly smaller than those on the fingers. The subarticular tubercles are large and round; the supernumerary tubercles are small, conical, and in a single row on the proximal segment of each toe. The toes are about three-fourths webbed (fig. 81A). The web extends from the distal end of the penultimate phalanx of the first toe to the base of the penultimate pha- lanx of the second toe and from the base of the disc on the second toe to the base of the penultimate phalanx of the third; from the base of the disc of the third toe the web con- tinues to the base of the penultimate phalanx of the fourth toe and on to the base of the disc of the fifth toe. The anal opening is directed posteroven- trally near the level of the upper edges of the thighs. The anal sheath is short and broad. The skin is smooth, except on the belly and ventral surfaces of the thighs where it is granu- lar. The tongue is ovoid, not or barely notched anteriorly and posteriorly, and free posteriorly for about one-fourth of its length. There are usually two to four (mean, 3.2) prevomerine teeth on small rounded processes between the large, round choanae. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Hyla inicroceph- ala microcephala is yellowish tan with two brown longitudinal stripes on the back and a brown longitudinal stripe on the flank, bor- dered above by a narrow white line (pi. 49, fig. 1). By day, most individuals are tan or pale reddish brown dorsally with dark brown longitudinal lines and brown flecks on the back. The dorsolateral stripe, which begins on the snout and extends to the groin, is creamy tan or yellow by day. The flanks are tan or pale reddish brown. The axilla, base of arm, groin and thighs are yellow. The shanks and feet are tan with brown flecks or a faint longitudinal brown line on the shank. The belly is white; in breeding males the vocal sac is pale yellow. The iris is bronze with a brown tint anterior and posterior to the pupil. In preservative, the venter is white; the dor- sum usually is creamy tan with faint brown lines. The thighs usually are pigmentless. Little geographic variation in color pat- tern has been observed. Of 103 specimens from the Canal Zone, all lack an interorbital bar, and all have a dark longitudinal line on the dorsal surface of the shank. The longi- tudinal lines on the dorsum are continuous to the anal region in 95 specimens and frag- mented in two specimens. In two others, the lines converge and fuse in the scapular region, 214 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 and in four specimens, additional fragmented lines are present dorsolaterally. The pattern is constant in all specimens from Puntarenas Province, Costa Rica, except that in about 10 per cent of the specimens the longitudinal line on the shank is replaced by brown flecks. Tadpoles: A typical tadpole in develop- mental stage 34 from Chepo, Panama, has a total length of 20.5 mm. and a body length of S.2 mm. The body is slightly wider than deep. The snout is pointed. The nostrils are large, situated dorsally much closer to the snout than to the eyes, and are directed an- teriorly. The eyes are moderately small, situ- ated dorsolaterally, and directed laterally. The spiracle is sinistral and lies just posteroventral to the eye; the anal tube is dextral. The caudal musculature of the xiphicercal tail is moder- ately deep, becoming slender posteriorly and extending beyond the caudal fin. The fins are deepest at about one-third the distance from the body to the tip of the tail. The dorsal fin is deeper than the deepest part of the caudal musculature and extends onto the body. The ventral fin is slightly shallower than the caudal musculature. The small, terminal mouth lacks teeth and fringing papillae but has finely serrate beaks (fig. 83). The top of the head and body are yellow- ish tan. A dark brown stripe extends from the snout through the eye to the posterior edge of the body, where the stripe narrows to a thin line midlaterally on the proximal one- fourth of the tail. The belly is white; the anterior half of the tail lacks pigment, whereas the posterior half is deep orange. The iris is pale bronze. In preserved specimens, the top of the head is pale brown, and the venter is white. The tail is creamy tan with fine black flecks, most numerous posteriorly. The pos- terior two-thirds of the caudal fins are edged with black (fig. 82). Mating Call: The call of Hyla m. micro- cephala is an insect-like "creeek-eek-eek-eek." Often, especially at the beginning of a series of call groups, only the unpaired primary note is given; at other times the primary note is followed by zero to 18 (usually about four) shorter, paired secondary notes. The repeti- tion rate of the secondaries is 192 to 353 (mean, 268) notes per minute. The duration of the primary note is 0.11 to 0.16 (mean, 0.13) of a second, and that of the secondary notes is 0.05 to 0.14 (mean, 0.10) of a second. The primary notes are characterized by a pulse rate of 150 to 210 (mean, 183) pulses per second. Each primary note has 19 to 22 ( mean, 20.5) pulses, and secondary notes have five to seven (mean, 5.8) pulses. The funda- mental frequency of normal primary notes is between 184 and 244 (mean, 205) cycles per second, and the dominant frequency varies from 5150 to 5962 (mean, 5637) cycles per second ( pi. 28, fig. 1 ) . Sometimes given indi- viduals emit exceptionally high primary notes. Fouquette (1960b) analyzed the high primary notes emitted by frogs from the Canal Zone and determined that the fundamental fre- quency varied from 315 to 419 (mean, 385.1) cycles per second and that the dominant fre- quency varied from 5300 to 5800 (mean, 5570) cycles per second. Natural History: Hyla microcephala mi- crocepliala apparently is not an inhabitant of primary forest, but instead occurs in disturbed areas, such as cut-over forests, second growth, and pastureland. It does not occur on the Ci/rate//rt-savannas on the Pacific lowlands of Panama. In the Canal Zone, this small frog breeds throughout the rainy season, which ex- tends from May through January; in the wet- ter coastal lowlands of eastern Puntarenas Province, Costa Rica, H. microcephala appar- ently breeds throughout the year. Breeding sites usually are shallow ditches, marshes, or temporary ponds. Calling males usually perch on grasses or reeds in, or at the edge of, the water. The eggs are deposited in small masses that float near the surface of the water and usually are attached to emergent vegetation. Remarks: Rivero (1961) and Duellman and Fouquette (1968) noted that Hyla micro- cephala may be conspecific with Hyla misera Werner, a species that is widely distributed east of the Andes in South America. The latter authors were reluctant to place the two taxa in the same species until data on the coloration in life, mating calls, and life history are avail- able for Hyla misera and compared with those of H. microcephala. Fouquette (1968) con- sidered misera as a subspecies of microceph- ala; this assignment was made principally on call data. 1970 DUELLMAN: HYLID FROGS 215 Duellman and Fouquette (1968) tenta- tively placed Hyla cherrei Cope in the synon- ymy of H. m. microcephala. The type speci- men apparently is lost, so the only extant in- formation regarding this taxon is that provided by Cope (1S94) in the type description. A reconsideration of the status of the name Hyla cherrei and an attempt to treat all such "un- known species" uniformly results in the place- ment of Hyla cherrei Cope in the Nomina Du- bita section of the present paper. Evidence for intergradation between H. m. microcephala and H. in. underwoodi is pro- vided by four specimens fU.S.C. Nos. 818 (2), 6081-6082] from 6.1 kilometers northeast of the mouth of the Rio Tarcoles, and nine speci- mens [U.S.C. Nos. 8254 (2), 8255, 8256 (4), 8258 (2)] from Parrita, both in Puntarenas Province, Costa Rica. In these specimens the dorsal pattern varies from nearly complete longitudinal lines to broken lines, fused into an X-shaped scapular mark or not. Some speci- mens have longitudinal lines on the shanks, whereas others have faint transverse markings. Etymology: The specific name micro- cepliala is derived from the Greek mikros, meaning small, and the Greek kcphale, mean- ing head, and is in reference to the character- istic small, narrow head of the species. Distribution : Hyla microcephala micro- cephala inhabits coastal lowlands from the area of the Golfo Dulee ( apparently absent in the Osa Peninsula ) in southeastern Costa Rica eastward in Panama, including the Azuero Peninsula, to northern Colombia and thence southward in the valleys of the Rio Cauca and Rio Magdalena in Colombia (fig. 85). Except for the central part of the Canal Zone, the subspecies is unknown from the Caribbean drainage in Central America, but in Colombia the subspecies occurs only in the Caribbean drainage. In Central America this frog occurs mostly on the coastal lowlands; the highest recorded elevation is 560 meters at El Valle, Code Province, Panama. See Appendix 1 for the locality records of the 477 specimens examined. Hyla microcephala underwoodi Boulenger Hyla microcephala Boulenger, 1898b, p. 481 [syn- types, B.M.N.H. Nos. 1947.2.23.28 and 29 from Bebe- dero, Guanacaste Province, Costa Rica; C. F. Under- wood collector (not Hyla microcephala Cope, 1886, p. 281, from Chiriqui Province, Panama)]. Hyla underwoodi Boulenger, 1899, p. 277 [substi- tute name for Hyla microcephala Boulenger, 1898b (preoccupied by Hyla microcephala Cope, 1886, p. 281)]. Gunther, 1901 (1885-1902), p. 278, Smith and Taylor, 1948, p. 85. Taylor, 1952c, p. 891. Hyla phlebod.es: Kellogg, 1932, p. 172 [not Hyla phlebodes Stejneger, 1906, p. 817 from San Carlos, Costa Rica]. Hyla microcephala martini Smith, 1951, p. 187 [holotype, U.I.M.N.H. No. 20965 from Encarnacion, Campeche, Mexico; Hobart M. Smith collector]. Stuart, 1963, p. 36. Hyla microcephala underwoodi: Smith, 1951, p. 187 [placed Hyla underwoodi Boulenger, 1899, as a subspecies of Hyla microcephala Cope, 1886]. Duell- man and Fouquette, 1968, p. 529. Diagnosis: Hyla microcephala under- woodi differs from other small Middle Ameri- can Hyla with uniformly yellow thighs by hav- ing a narrow lateral dark brown stripe extend- ing to the sacral region or groin, bordered above by a narrow white line, and a bold dor- sal pattern consisting of variously arranged dark lines or dashes, not in the form of a pair of longitudinal lines. An interorbital dark mark usually is present, and the shanks usu- ally have dark transverse marks. Hyla phle- bodes differs by having a short lateral dark stripe, if present at all, and lacking a dorso- lateral white line; furthermore, the dorsal markings are much weaker than in H. m. underwoodi. Hyla m. microcephala differs by having a pair of longitudinal dark lines on the dorsum extending to the vent and the shanks with a dark longitudinal line or flecks, and by lacking a dark interorbital mark. Description: Males of this small frog at- tain a maximum snout-vent length of 25.9 mm. (mean, 25 specimens from Alvarado, Veracruz, Mexico, 24.1 mm.), and females reach 30.6 mm. (mean, six specimens, 29.3 mm. ) . In a sample of 25 males from Alvarado, Veracruz, Mexico, the ratio of the tibia length to snout-vent length is 0.496 to 0.544 (mean, 0.511); the ratio of foot length to snout-vent length is 0.407 to 0.475 (mean, 0.426); the ratio of head length to snout-vent length is 0.299 to 0.338 (mean, 0.314); the ratio of head width to snout-vent length is 0.291 to 0.329 ( mean, 0.305 ) , and the ratio of the diameter of the tympanum to that of the eye is 0.407 216 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 to 0.538 (mean, 0.466). Although minor dif- ferences are apparent in certain proportions in five samples from throughout the range ( Duellman and Fouquette, 1968, table 1 ) , the only noticeable variant is the slightly larger tympanum in specimens from Hacienda La Cumplida, Nicaragua. In 25 males from there, the ratio of the diameter of the tym- panum to that of the eye is 0.423 to 0.600 (mean, 0.493). Structurally Hyla microcephala under- ivoodi is like the nominate subspecies; the reader is referred to the account of Hyla mi- crocephala microcephala for a detailed de- scription. The general coloration of Hyla microceph- ala underivoodi at night consists of a pale yellow dorsum with brown or tan markings or flecks. Ry day the dorsum is yellowish tan or pale brown with dark brown or reddish brown markings; the thighs are uniform yel- low (pi. 49, fig. 2). The venter is white, and the vocal sac in breeding males is yellow. The iris is bronze with a brown tint anterior and posterior to the pupil. The dorsal color pat- tern is highly variable. The markings on the back usually consist of interconnected dark lines forming an X-shaped mark in the scapu- lar region or a pair of longitudinal lines that are either connected by crossbars or are frag- mented. In other specimens, the dorsum is marked with irregular dark flecks or dashes (fig. 86). With the exception of a few speci- mens from Costa Rica, most specimens have a dark brown interorbital mark and distinct dark brown transverse bars on the limbs. The lateral brown stripe extends only to the sacral region in most specimens from the northern part of the range (Mexico and Guatemala), whereas in many individuals from Costa Rica, the stripe extends to the groin, thereby ap- proaching the pattern characteristic of the nominate subspecies. Duellman and Fou- quette (1968) presented an analysis of varia- tion of the color pattern in 12 samples of Hyla microcephala underivoodi. Tadpoles: A typical tadpole in develop- mental stage 37 from 10 kilometers east of Esparta, Costa Rica, has a total length of 28.0 mm. and a body length of 9.2 mm. The struc- ture of the body and mouth is like that of the nominate subspecies. The coloration differs from that of the nominate subspecies; in Hyla m. underivoodi there is no dark line on the anterior part of the tail, and the tail is more heavily pigmented than in Hyla m. micro- cephala (fig. 82). Mating Call: The call of H. m. under- ivoodi is like that of the nominate subspecies in being an insect-like "creek-eek-eek-eek." The primary note is unpaired, and the secon- daries are paired. When the primary note is not given alone, it is followed by zero to 18 (usually about four) secondary notes. The repetition rate of the secondaries is 197 to 384 (mean, 283) notes per minute. The duration of the primary note is 0.05 to 0.15 (mean, 0.11) of a second and that of the secondary notes is 0.06 to 0.11 (mean, 0.09) of a second. The primary notes have a pulse Fig. 86. Variation in dorsal color pattern in Hijla microcephala underivoodi. A. K.U. No. 57525. B. K.U. No. 57535. C. K.U. No. 57515. D. K.U. No. 65068. E. K.U. No. 65076. 1970 DUELLMAN: HYLID FROGS 217 rate of 130 to 150 (mean, 143) pulses per second. Each primary note has 19 to 22 (mean, 20.3) pulses, and secondary notes have four to six (mean, 4.8) pulses. The fundamental frequency of normal primary notes is between 192 and 275 ( mean, 220 ) cycles per second, and the dominant fre- quency varies from 5177 to 6200 (mean, 5772) cycles per second (pi. 28, fig. 1). Some indi- viduals produce high-pitched primary notes, as well as the normal notes described here. The duration of the primary note is longest in Mexico and shorter in the southern part of the range, although the primary notes are slightly longer in H. m. microcephala than in any underwoodi. In the latter subspecies the dominant and fundamental frequencies are lower in Costa Rica than in the more northern populations. Natural History: Hyla microcephala un- derwoodi inhabits xeric and subhumid forests and savannas, where it congregates around temporary ponds in great numbers during the breeding season — usually June through Sep- tember or October. Males usually call from emergent plants or grasses and sedges border- ing the water. The eggs are laid in small clumps near the surface of the water and usually attached to emergent vegetation. In- dividuals of H. m. underwoodi have been found by day under the outer sheaths of ba- nana plants next to a water-filled ditch at Tuxtepec, Oaxaca, Mexico. At Bebedero, Costa Rica, males began calling at dusk from trees near a small marsh. Remarks: The confused nomenclatural history of this taxon was discussed in detail by Duellman and Fouquette (1968), so only the status of various names that have been ap- plied are reviewed here. Hyla underwoodi was proposed by Boulenger (1899) as a sub- stitute name for Hyla microcephala Boulenger (1898b), preoccupied by Hyla microcephala Cope (1886). Hyla microcephala underwoodi, as now recognized, has been confused with Hyla phlebodes Stejneger (1906). Smith ( 1951 ) named Hyla microcephala martini from southern Mexico and Guatemala and considered the northern populations to represent a subspecies distinct from the Costa Rican Hyla microcephala underwoodi. The acquisition of specimens from throughout southern Mexico and Central America negates the recognition of two taxa north of Costa Rica. Hence, Hyla microcephala martini Smith ( 1951 ) was placed in the synonymy of Hyla microcephala underwoodi Boulenger (1899) by Duellman and Fouquette (1968). The evidence for intergradation between Hyla m. microcephala and H. m. underwoodi is dis- cussed in the account of the former subspecies. Etymology: The trivial name underwoodi is a patronym for Mr. C. F. Underwood, the collector of the type specimen in the British Museum (Natural History). Distribution: Hyla microcephala under- woodi inhabits the Atlantic slopes and low- lands from southern Veracruz and extreme northern Oaxaca eastward across the base of the Yucatan Peninsula to British Honduras and thence southeastward through the Carib- bean lowlands and interior valleys in Hon- duras to central Nicaragua, where it appar- ently avoids the forested Caribbean lowlands and the dry Pacific lowlands of northwestern Nicaragua, but in the vicinity of Managua invades the Pacific lowlands and continues southward into northwestern Costa Rica as far as the Puntarenas Peninsula (fig. 85). In Mexico and Guatemala the species has not been taken at elevations of more than 350 meters, whereas farther south it occurs at higher elevations — 780 meters at Silencio, Costa Rica; 830 meters on Montana de Guai- maca, Honduras; 960 meters at Finca Tepeyac, Nicaragua; and 1200 meters at Finca Venecia, Nicaragua. The specimens from Chichen-Itza, Yuca- tan, represent the only record for this species in the arid northern part of the peninsula. At least two specimens (M.C.Z. No. 2463) came from cenotes surrounded by evergreen vege- tation. If the species is extant in the northern part of the peninsula, its distribution probably is limited to petenes and cenotes. See Appendix 1 for the locality records of the 1389 specimens examined. Hyla robertmertensi Taylor Hi/Ia robertmertensi Taylor, 1937, p. 43 [holorype, F.M.N. H. No. 100096 (formerly E.H.T.-H.M.S. No. 2270) from Tapachula, Chiapas, Mexico; Hobart M. 21S MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Smith and Edward H. Taylor collectors]. Smith and Taylor, 1948, p. 84. Stuart, 1963, p. 36. Duellman and Fouquette, 1968, p. 534. Diagnosis: This small species can be dis- tinguished from other Middle American Hyla with uniformly yellow thighs by the presence of a broad dark brown lateral stripe including the loreal region and entire tympanum and extending to the groin, bordered above by a narrow white line. The yellowish tan dorsum usually is marked by a pair of dark brown longitudinal lines or series of dashes; an inter- orbital dark mark is invariably absent. Hyla picta and smitlti in northern Middle America have broader dorsolateral white lines and pro- portionately wider heads, and H. m. micro- cephaly, has a much narrower lateral dark stripe. Specimens of H. robertmertensi lack- ing dorsal markings resemble some specimens of H. ebraccata, in which the dorsal dark markings are absent; the latter species has a wide head, extensive axillary membrane, and a white spot below the eye, all of which serve to distinguish that species from H. robert- mertensi. Description: This is a small, slender spe- cies; males attain a maximum snout-vent length of 26.4 mm. ( mean, 25 specimens from Tapanatepec, Oaxaca, 24.7 mm. ) , and females reach 28.1 mm. (mean, six specimens from Tapanatepec, 26.6 mm. ) . In a sample of 25 males from Tapanatepec the ratio of tibia length to snout-vent length is 0.441 to 0.4S3 (mean, 0.464); the ratio of foot length to snout-vent length is 0.391 to 0.445 (mean, 0.417); the ratio of the head length to snout- vent length is 0.261 to 0.304 (mean, 0.284); the ratio of head width to snout-vent length is 0.254 to 0.281 (mean, 0.268), and the ratio of the diameter of the tvmpanum to that of the eye is 0.458 to 0.553 (mean, 0.529). Speci- mens from the eastern part of the range are slightly smaller; in a sample of 25 males from La Trinidad, Guatemala the maximum snout- vent length is 24.6 mm., and the mean is 23.4 mm. Furthermore, specimens from Guate- mala and Chiapas differ in certain proportions from specimens from Oaxaca, which have pro- portionately smaller heads and larger tym- pani (table 23). The head is narrower than the body; the top of the head is flat. In dorsal profile the snout is narrowed anteriorly but truncate terminally; in lateral profile the snout is trun- cate and slightly inclined posteroventrally. The snout is short; the nostrils are barely protuberant and situated about three-fourths the distance from the eyes to the tip of the snout. The canthus is round and indistinct; the loreal region is nearly flat, and the lips are thin and barely flared. A thin dermal fold extending from the posterior corner of the eye to a point above the insertion of the arm obscures the upper edge of the tympanum. The tympanum is faint and is situated postero- ventral to the eye and separated from the eye by a distance about equal to the diameter of the tympanum. The arm is moderately long and slender; an axillary membrane is present. Dermal folds along the outer edge of the forearm and across the wrist are absent. The fingers are short and broad; the discs are rather small, not quite as large as the tympanum. The subarticular tu- bercles are large and round; in most speci- mens the distal tubercles on the third and fourth fingers are bifid. The supernumerary TARLE 23 Comparison of Certain Proportions, with Means in Parentheses, of Adult Males of Hyla robertmertensi. Locality N Tibia Length/ S-V L Head Length/ S-V L Head Width/ S-V L Tympanum/ Eye Guatemala: La Trinidad 25 Chiapas : Aeacoyagua 25 Oaxaca: Tapanatepec 25 0.471-0.528 (0.499) 0.478-0.524 (0.504) 0.441-0.483 (0.464) 0.300-0.333 (0.313) 0.291-0.327 (0.312) 0.261-0.304 (0.284) 0.273-0.298 (0.285) 0.260-0.303 (0.281) 0.254-0.281 (0.268) 0.444-0.500 (0.474) 0.428-0.538 (0.465) 0.45S-0.583 (0.529) 1970 DUELLMAN: HYLID FROGS 219 tubercles are large, conical, and in a single row on the proximal segment of each finger. The prepollex is moderately enlarged; breed- ing males lack a horny nuptial excrescence. The fingers are about one-half webbed (fig. SOB). The webbing is vestigial between the first and second fingers and connects the mid- dle of the penultimate phalanx of the second finger to the base of the antepenultimate pha- lanx of the third finger. The web extends from the middle of the antepenultimate pha- lanx of the third finger to the base of the penultimate phalanx of the fourth finger. The hind limbs are moderately short. The ad- pressed heels overlap by about one-third the length of the shank, and the tibiotarsal articu- lation extends to the eye. A weak tarsal fold extends the length of the tarsus. The inner metatarsal tubercle is small, rounded, and elongate. The toes are moderately long and slender; the discs are smaller than those on the fingers. The subarticular tubercles are small, high, and round; the supernumerary tubercles are low and indistinct. The toes are about three-fourths webbed (fig. SIB). The web extends from the distal end of the penultimate phalanx of the first toe to the middle of the penultimate phalanx of the second, from the base of the disc of the sec- ond to the base of the penultimate phalanx of the third, and from the base of the disc of the third to the base of the penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly at the level of the upper edges of the thighs. The anal sheath is short. The skin is smooth, except on the belly and ventral surfaces of the thighs where it is granular. The tongue is small, ovoid, not or barely notched anteriorly and posteriorly, and free behind for about one- fifth of its length. There are two or three (mean, 2.7) teeth on each small prevomerine process between the small round choanae. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Ihjhi robert- mertensi is pale yellow above with a white dorsolateral line and a pale brown lateral stripe at night. By day, the dorsum is yellow- ish tan or pale reddish tan with brown mark- ings; the narrow dorsolateral line is creamy white, and the flanks are dark brown (pi. 49, fig. 3). Invariably the thighs are uniform yellow, the venter is white, and there is no interorbital dark mark. The dark brown on the sides of the body is continuous across the end of the snout and extends to the groin. The brown lateral stripe encompasses the entire tympanum. The narrow white line also is continuous across the snout and extends pos- teriorly at least to the sacral region. In most specimens, the dorsal pattern consists of flecks or dashes arranged in two parallel longitudi- nal rows; in some specimens, the marks are fused into parallel lines. Small brown flecks are present on the dorsal surfaces of the shanks; in some specimens, these flecks tend to form a longitudinal stripe on the shank. The iris is dull bronze with a brown tint an- terior and posterior to the pupil. In breeding males the vocal sac is yellow. In preservative, the venter is white; the dorsum is grayish tan or yellowish tan with brown or dark gray marks. The thighs usually have no pigment. The color pattern shows little geographic variation, except in the nature of the dorsal markings. A few specimens from throughout the range lack dark markings on the dorsum between the dorsolateral white lines. The unicolor dorsum is most common in samples from southeastern Guatemala and El Salvador. Tadpoles: The tadpoles of this species are unknown. Presumably, the tadpoles live in grassy temporary ponds and are like those of other species in the Hyla microccphaJa group in having xiphicercal tails and mouths lacking teeth and papillae. Mating Call: The mating call of Hyla robertmertensi is an insect-like "cree-eek-eek- eek," consisting of a paired primary note, usually followed by zero to 28 (mean, 3) shorter, unpaired secondary notes (pi. 2S, fig. 3). The repetition rate of the secondaries is 368 to 570 (mean, 418) notes per minute. The duration of the primary notes is 0.07 to 0.11 (mean, 0.09) of a second, and that of the secondary notes is 0.03 to 0.06 (mean, 0.04) of a second. The primary notes are character- ized by a pulse rate of 140 to 164 (mean, 149) pulses per second. Each primary note has 220 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 nine to 12 (mean, 10.5) pulses, and secondary notes have three or four (mean, 3.4) pulses. The fundamental frequency of primary notes is between 140 and 178 (mean, 162) cycles per second, and the dominant frequency va- ries from 5150 to 5785 (mean, 5388) cycles per second. Natural History: Hyla robertmertensi inhabits the subhumid and humid lowlands and foothills. In this habitat it lives in cut-over forest and low scrubby forest. It does not seem to inhabit primary forest. The species does not occur on the xeric Plains of Tehuan- tepee or in the xeric scrub forest in eastern El Salvador and southern Honduras. The dry season retreats of Hyla robertmer- tensi are not known. In the rainy season, frogs of this species congregate in large numbers at temporary ponds, where the males call from grasses, bushes, and low trees. The eggs are unknown. Remarks: Hyla robertmertensi is a dis- tinctive species and occupies a region inhab- ited by only one other small pond-breeding hylid — Hyla stanfferi. Usually the two species breed at the same season and at the same sites, although Hyla staufferi seems to become ac- tive when less rain has fallen than normally brings about activity in H. robertmertensi. Etymology: The specific name robert- mertensi is a patronym for Dr. Robert Mertens of the Senckenberg Museum. Distribution: Hyla robertmertensi inhab- its the Pacific lowlands and foothills, to eleva- tions of 700 meters from extreme eastern Oaxaca (east of the Plains of Tehuantepec) southeastward to central El Salvador. The species also occurs in the Cintalapa Valley (Atlantic drainage) in southwestern Chiapas (fig. 87). The distribution of the species seems to be limited on the northwest and southeast by xeric environments. Hyla rob- ertmertensi inhabits an area along the Pacific coast of Central America that has higher rain- fall and more luxuriant vegetation than the regions immediately to the northwest or south- east. In addition to the localities listed in the Appendix 1, Mertens (1952b, p. 30) recorded the species from Hacienda Cuyan-Cuya, Son- sonate, El Salvador. See Appendix 1 for the locality records of the 511 specimens examined. Hyla phlebodes Stejneger Hyla phlebodes Stejneger, 1906, p. 817 [holotype, U.S.N. M. No. 2997 from "San Carlos," Alajuela Pro- vince, Costa Rica; Burgdorf and Schild collectors]. Taylor, 1952c, p. 888. Duellman and Fouqnette, 1968 p. 536. Diagnosis: Hyla phlebodes can be distin- guished from other species of Middle Ameri- can hylids having uniformly yellow thighs by a yellowish tan dorsum with darker irregular dashes or interconnecting lines; if a dark brown lateral stripe is present it usually ex- tends only to the insertion of the forearm, never posteriorly to the sacral region. Hyla phlebodes can be distinguished from H. micro- cephala undencoodi by having a short lateral dark stripe that is not bordered above by a narrow white line; in the latter species the lateral dark stripe extends to the sacral region or to the groin and is bordered above by a narrow white line. Furthermore, the dorsal markings of H. microcephala undencoodi are bolder than in H. phlebodes. Description: This is the smallest species in the Hyla microcephala group. Males attain a maximum snout-vent length of 23.6 mm. ( mean, 25 specimens from Turrialba, Cartago Province, Costa Rica, 22.0 mm.), and females reach 27.8 mm. (mean, seven specimens, 26.8 mm. ) . In a sample of 25 males from Turrialba, the ratio of tibia length to snout-vent length is 0.474 to 0.557 (mean, 0.511); the ratio of foot length to snout-vent length is 0.381 to 0.464 ( mean, 0.428 ) ; the ratio of head length to snout-vent length is 0.326 to 0.359 (mean, 0.341); the ratio of head width to snout-vent length is 0.305 to 0.350 (mean, 0.329), and the ratio of the diameter of the tympanum to that of the eye is 0.357 to 0.482 ( mean, 0.401 ) . No geographic variation in size and propor- tions is evident among four samples from Costa Rica and Panama. The head is as wide as, or a little wider than, the body; the top of the head is flat. In dorsal and lateral profile, the snout is truncate. The snout is short; the nostrils are slightly pro- tuberant and situated about two-thirds the distance from the eyes to the tip of the snout. The canthus is round and indistinct. The loreal region is barely concave, and the lips are thin and barely flared. A thin dermal fold extending from the posterior corner of the 1970 DUELLMAN: HYLID FROGS 221 90c 18°- • <- 0 50 100 200 i i i 1 KILOMETERS 94° 92° 90° 88c Fig. 87. Distribution of Hyla robertmertensi eye to a point above the insertion of the arm obscures the upper edge of the tympanum, which is weakly differentiated. The tympanum is posteroventral to the eye and separated from the eye by a distance equal to half again the diameter of the tympanum. The arm is moderately short and robust; a distinct axillary membrane is present. Der- mal folds are absent on the outer edge of the forearm and across the wrist. The fingers are moderately long and slender and have large discs; the diameter of the disc on the third finger is equal to the diameter of the tym- panum. The subarticular tubercles are large and round; the distal tubercle on the fourth finger is bifid in about one-third of the speci- mens. The supernumerary tubercles are low and indistinct. The prepollex is moderately enlarged; breeding males lack a horny nuptial excrescence. The fingers are about one-third webbed (fig. 80C). The webbing is vestigial between the first and second fingers and con- nects the base of the penultimate phalanx of the second finger to the base of the antepenul- timate phalanx of the third and the middle of the antepenultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are mod- erately short and robust; the adpressed heels overlap by about one-third the length of the shank. The tibiotarsal articulation extends to a point about midway between the eye and the nostril. A tarsal fold is absent. The inner metatarsal tubercle is low, flat, and elongate. 222 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 The toes are moderately long and slender; the discs are smaller than those on the hand. The subarticular tubercles are small and round, and the supernumerary tubercles are low and indistinct. The toes are about three-fourths webbed (fig. 81C). The web extends from the middle of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second to the middle of the antepenulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the level of the upper edges of the thighs. The anal sheath is extremely short. The skin is granular on the belly and proximal ventral surfaces of the thighs and smooth on other surfaces of the body. The tongue is cordi- form. not or shallowly notched behind, and free posteriorly for about one-fourth its length. There are two to five ( mean, 3.9 ) prevomerine teeth on small posteromedially slanting eleva- tions between the small ovoid choanae. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Hijla phlebodes is pale yellowish tan with weak darker brown markings on the dorsum ( pi. 49, fig. 4 ) . The flanks are pale yellow; the belly is white. The thighs are uniform yellow, and the shanks are tan with narrow brown transverse bars. The iris is creamy bronze with brown flecks and a brown tint anterior and posterior to the pupil. In breeding males, the vocal sac is yellow. In preservative, the dorsum is pale creamy gray with faint brown markings; the belly is white, and the thighs lack pigment. A dark brown stripe extends from the nostril to the eye and thence above the tym- panum to a point above the insertion of the forearm in 70 per cent of the specimens; in 17 per cent the stripe extends to midflank, and in 13 per cent the stripe is absent. A nar- row, faint white line is present on the canthus in some specimens but no distinct white stripe is present above the lateral dark line posterior to the eye. An interorbital bar and transverse marks on the shanks are invariably present. The dorsal markings are variable, but in 92 percent of the specimens an X- or )( -shaped mark is present in the scapular region; in other specimens, scapular markings are absent or consist of irregularly arranged short lines. A few specimens lack markings in the sacral region; most individuals have a transverse bar, chevron, or broken lines in the sacral region. Tadpoles: Series of tadpoles are available from Puerto Viejo and Turrialba, Costa Rica. A typical tadpole in developmental stage 36 from the former locality has a total length of 21.0 mm. and a body length of 6.7 mm. The body is slightly wider than deep, and the snout is pointed. The nostrils are large and directed anteriorly near the end of the snout. The eyes are small, situated dorso- laterally, and directed laterally. The spiracle is sinistral and lies just posteroventral to the eye; the anal tube is dextral. The caudal musculature of the xiphicercal tail is moder- ately deep and extends well beyond the pos- terior edge of the caudal fin. The fins are deepest at about midlength of the tail. The dorsal fin extends onto the body and is slightly deeper than the caudal musculature; the ven- tral fin is slightly shallower than the muscu- lature. The small terminal mouth lacks teeth and fringing papillae but has finely serrate beaks. The dorsal surfaces of the head and body are reddish tan mottled with brown. A dark brown stripe extends from the snout through the eye to the posterior end of the body. The belly is white, mottled with brown and black. The caudal musculature is heavily pigmented with grayish tan, and the tip of the tail is dark gray. The caudal fins are heavily blotched with grayish tan. The iris is orange-tan pe- ripherally and red centrally. In preservative, the dorsal surfaces of the head and body are olive-tan with brown flecks; the belly is white, flecked with brown anteriorly. The tail is creamv tan with grayish brown blotches (fig. 82C). Mating Call: The mating call of Hijla phlebodes is an insect-like "creek-eek-eek- eek." Although individuals sometimes produce only primary notes, the entire mating call con- sists of a single, unpaired primary note fol- lowed by as many as 28 shorter, unpaired sec- ondary notes. The note repetition rate of the secondaries is 210 to 350 (mean, 284) notes 1970 DUELLMAN: HYLID FROGS 223 per minute. The duration of the primary note is 0.07 to 0.16 (mean, 0.11) of a second, and that of the secondary notes is 0.04 to 0.12 (mean, 0.07) of a second. The primary notes have a pulse rate of 140 to 170 (mean, 152) pulses per second. Each primary note is com- posed of 13 to 15 (mean, 14.1) pulses, whereas secondary notes are made up of three to eight (mean, 5.0) pulses. The fundamental fre- quency of the primary notes is 125 to 158 ( mean, 148 ) cycles per second, and the domi- nant frequency varies from 3220 to 4067 (mean, 3578) cycles per second (pi. 28, fig. 2). Hylu phlebodes at Puerto Viejo, Costa Rica, produce calls with slightly lower domi- nant frequencies than do those from Tur- rialba, Costa Rica, and Panama, whereas those at Turrialba have lower fundamental frequen- cies than in other samples. Calls recorded at both Costa Rican localities have slightly shorter notes than those recorded in Panama. Natural History: Hyla phlebodes inhab- its lowland humid forests, where it breeds in shallow, grassy, temporary ponds. Since this small frog lives in areas where the rainfall is generally distributed throughout the year, males probably call throughout the year. How- ever, large breeding congregations are most common at the early part of the rainy season. Breeding activity in Hyla phlebodes usually reaches a peak one or two nights after a heavy rain and not on the night of a heavy rain (Duellman and Fouquette, 1968). Males call from grasses or sedges in, or at the edge of, ponds. The eggs are deposited in small masses that float near the surface of the water and usually are attached to emer- gent vegetation. The tadpoles live in shallow- parts of the pond; they are most frequently found amidst submergent vegetation. Remarks: The literature pertaining to Hyla phlebodes is greatly confused, because of the misidentification of specimens and the misapplication of the name Hyla undencoodi Boulenger ( see detailed discussion of various usages in Duellman and Fouquette, 1968). Taylor (1962c) correctly determined the ap- plication of the name Hyla phlebodes, al- though he was uncertain about the status of Hyla undencoodi. Taylor (1952c) interpreted the originally designated type locality, "San Carlos, Costa Rica," to be the "Comandancia de San Carlos at the junction of the Rio Arenal and Rio San Carlos"; Duellman and Fouquette ( 1968 ) sug- gested that the designated type locality appar- ently refers to the Llanuras de San Carlos, the name given to a broad lowland region in the northern part of Alajuela Province. Etymology: The specific name phlebodes is derived from the Greek phlebos, meaning vein, which with the Greek suffix -odes, mean- ing like, alludes to the vein-like arrangement of dark markings on the dorsum. Distribution: Hyla phlebodes ranges from southeastern Nicaragua southeastward on the Caribbean slopes and lowlands to the Canal Zone in Panama, thence eastward in the Chucunaque Basin of eastern Panama and on to the Pacific lowlands of Colombia (fig. 88). The species reached the Pacific slopes in the Arenal Depression in northwestern Costa Rica and in the Panamanian isthmus, where it oc- curs in humid forests on the Pacific slopes at El Valle and Cerro La Campana. The northern extent of the range is unknown; specimens are known from El Recreo and Isla Grande del Maiz in Nicaragua, but possibly the species occurs as far north as Bonanza. Most localities where Hyla phlebodes has been found are at low elevations, but the species occurs at ele- vations of 600 meters at Turrialba and 700 meters at Finca San Bosco in Costa Rica. See Appendix 1 for the locality records of the 428 specimens examined. Hyla sartori Smith Hyla undencoodi: Smith and Taylor, 1948, p. 85 [part, specimens from Guerrero]. Hyla microcephala sartori Smith, 1951, p. 186 [holotype, U.I.M.N.H. No. 20934 from 1 mile north of Organos, south of El Treinte, Guerrero, Mexico; lie I. art M. Smith and Edward H. Taylor collectors]. Hyla sartori: Savage, 1966, p. 752. Duellman and Fouquette, 1968, p. 538 [recognized Hyla sartori Smith, 1951, as a species distinct from Hyla microce- phala Cope, 1886]. Diagnosis: This small species is distin- guished from other Hyla with uniformly yel- low thighs by having a dark interorbital bar, broad dark brown chevrons or transverse bands on the dorsum, and two or three broad, transverse, dark brown bars on each shank, 224 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 88. Distribution of Hijla phlebodes. and by lacking a dorsolateral white stripe and extensive axillary membrane. Other small Middle American Hyla with uniformly yellow thighs either have no dorsal markings (H. bromeliacea, dendroscarta, and sumichrasti) , small flecks on the dorsum (H. melanomma) , various interconnecting or straight dark lines and at least a short white dorsolateral stripe (H. microcephah, phlebodes, and robertmer- tensi), or distinct longitudinal white stripes (H. picta and smithi). Hyla ebraccata has dark flanks, a white spot below the eye, no transverse bands on the shanks, an extensive axillary membrane, and an hour-glass-shaped dark mark, small dark spots, or no pattern on the dorsum. Description: Males of this small species attain a maximum snout-vent length of 26.0 mm. (mean, 25 specimens from Tierra Colora- da, Guerrero, Mexico, 24.8 mm.), and females reach 28.6 mm. In the sample of 25 males from Tierra Colorada the ratio of tibia length to snout-vent length is 0.472 to 0.514 (mean, 0.496); the ratio of foot length to snout- vent length is 0.424 to 0.478 (mean, 0.452); the ratio of head length to snout-vent length is 0.289 to 0.310 (mean, 0.300), and the ratio of the diameter of the tympanum to that of the eye is 0.423 to 0.520 (mean, 0.474). No geo- graphic variation in size and proportions is evident. The head is as wide as the body; the top of the head is slightly convex. In dorsal pro- file the snout is truncate; in lateral profile, it is bluntly rounded. The snout is short; the nostrils are slightly protuberant and situated about two-thirds of the distance from the eyes to the tip of the snout. The canthus is round and indistinct. The loreal region is concave; the lips are moderately thick and not flared. A thin dermal fold extends posteriorly from the posterior corner of the eye, covers the upper edge of the tympanum, and curves downward behind the tympanum to the place of insertion of the arm. The tympanum other- wise is distinct and is separated from the eye 1970 DUELLMAN: HYLID FROGS 225 by a distance equal to the diameter of the tympanum. The arm is moderately short and robust; a distinct axillary membrane is present. Der- mal folds are absent on the outer edge of the forearm and across the wrist. The fingers are short and stout. The discs are large; the diameter of the disc on the third finger equals the diameter of the tympanum. The subartic- ular tubercles are large and round; the distal tubercles on the third and fourth fingers are bifid in most specimens. The supernumerary tubercles are small and round; they are ar- ranged in two rows on the proximal segment of the third finger and in one row on the other fingers. The prepollex is moderately enlarged; breeding males lack a horny nuptial excrescence. The fingers are about one-third webbed (fig. SOD). The webbing is vestigial between the first and second fingers, but ex- tends from the base of the penultimate pha- lanx of the second to the base of the antepen- ultimate phalanx of the third, from the middle of the antepenultimate phalanx of the third to the distal end of the antepenultimate pha- lanx of the fourth finger. The hind limbs are moderately short and robust; the adpressed heels overlap by about one-fourth the length of the shank. The tibiotarsal articulation ex- tends to the posterior corner of the eye. The tarsal fold is moderately strong and extends the full length of the tarsus. The inner meta- tarsal tubercle is low, flat, and elongate. The toes are moderately long and slender; the discs are much smaller than those on the fingers. The subarticular tubercles are small and round; the supernumerary tubercles are indistinct. The toes are about three-fourths webbed (fig. 81D). The web extends from the base of the disc of the first toe to the base of the penultimate phalanx of the second, from the base of the disc of the second to the base of the penultimate phalanx of the third, from the base of the disc of the third to the base of the penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. The anal sheath is short. The belly and ventral surfaces of the thighs are granular; the skin on the other surfaces is smooth. The tongue is cordi- form, shallowly notched behind or not, and free posteriorly for about one-fourth of its length. There are three or four (mean, 3.7) prevomerine teeth on elongate medially slant- ing elevations between the elliptical choanae. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration at night is pale yellowish tan with broad transverse dark brown markings on the back; by day the dor- sum is reddish tan with brown markings (pi. 49, fig. 5). The flanks are pale yellowish tan, and the thighs are yellow. The side of the head is brown; a narrow white line is present along the canthal ridge. A dark brown inter- orbital bar is invariably present. The mark- ings on the back consist of a broad brown chevron in the scapular region and a chevron or transverse bar in the sacral region. The thighs are marked by two or three dark brown transverse bars. The belly is white; in breed- ing males the vocal sac is yellow. The iris is dark bronze with a brown tint anterior and posterior to the eye. By day some individuals become creamy gray with indistinct darker markings. In preservative, the dorsum is tan or gray with brown markings; the belly is creamy white, and the thighs lack pigment. Tadpoles: The tadpoles of Hyla sartori have not been found. Probably they live in shallow ponds like those inhabited by tad- poles of other species in the Hyla micro- cephala group. Mating Call: Hyla sartori has a mating call consisting of an insect-like series of notes. Although individuals sometimes emit only single notes, the complete mating call consists of an unpaired primary note followed by as many as 23 shorter, unpaired secondary notes. The note repetition rate of the secondaries is 396 to 477 ( mean, 434 ) notes per minute. The duration of the primary note varies from 0.07 to 0.09 (mean, 0.08) of a second and of the secondaries from 0.04 to 0.07 (mean, 0.05) of a second. The primary notes have a pulse rate of 140 to 160 (mean, 149) pulses per second. Primary notes are composed of seven to 10 (mean, 8.5) pulses, whereas secondary notes are made up of three to five (mean, 3.4) pulses. The fundamental frequency of 226 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 the primary notes vary from 116 to 135 (mean, 126) cycles per second, and the domi- nant frequency varies from 2950 to 3600 (mean, 3217) cycles per second (pi. 29, fig. 3). Natural History: This is the least known species in the Hijla microcephala group. After heavy rains, breeding congregations have been found at temporary ponds and at a pool in a stream. Males call from grasses, bushes, and low trees around the ponds. Recause Hyla sartori inhabits a drier region having a rela- tively shorter rainy season than do other spe- cies in the Hyla microcephala group, the breeding season of sartori probably is more restricted than that of the other species. Remarks: Smith (1951, p. 186) named Hyla sartori as a subspecies of Hyla micro- cephala. Duellman and Fouquette (1968) demonstrated that on the basis of mating call and certain morphological characters sartori was more closely related to phlebodes than microcephala. Savage (1966, p. 752) prema- turely used the combination Hyla sartori with- out providing evidence for the specific recog- nition. Etymology: The specific name sartori is "from the Latin sartor, meaning tailor; here used loosely in reference to Edward H. Taylor . . ." (Smith, 1951, p. 186). Distribution: Hyla sartori is known from mesophytic forests to elevations of about 300 meters on the Pacific slopes of southern Mex- ico from southwestern Jalisco to south-central Oaxaca (fig. 89). The absence of specimens from Miehoacan and Colima probably is an artifact of collecting. The species probably occurs in southwestern Nayarit. The xeric Plains of Tehuantepec apparently limit the eastward distribution of the species. See Appendix 1 for the locality records of the 193 specimens examined. The Hyla leucophyllata Group Definition: The members of this group are small species; males attain a maximum snout-vent length of about 35 mm. and fe- males, 42 mm. The dorsum is white, yellow, or tan with or without dark brown spots or large markings. In at least one species, most of the dorsum is brown, and the ground color is reduced to a network of fine lines. The thighs are colorless in preservative but are yellow, orange, pink or red in life. The pal- pebral membrane is clear. The fingers are about one-half webbed, and the toes are about three-fourths webbed. Dermal folds and appendages are lacking on the limbs. 2C) 0 50 100 200 ' ' ' — i KILOMETERS 104° 100° 96° Fig. 89. Distribution of Hyla sartori. 1970 DUELLMAN: HYLID FROGS 227 The axillary membrane is extensive, and a pair of oval glandular areas are present on the chest. Males have single, median, subgular vocal sacs, but lack nuptial excrescences on the pollices. The ossification of the cranial ele- ments is moderately reduced (fig. 90). An elongate frontoparietal fontanelle is present, and the quadratojugal is much reduced and not in contact with the maxillary. The sphen- ethmoid is much wider than long, and the anterior arm of the squamosal is short and extends about one-fourth the distance to the maxillary. Prevomerine teeth are present. The known tadpoles have xiphicercal tails and a terminal mouth lacking teeth and labial pa- pillae. The mating call consists of a distinctly pulsed primary note followed or not by one or more secondary notes. In those species for which counts have been obtained, the haploid number of chromosomes is 15. Composition-: Only one species, Hyla ebraccata, occurs in Middle America, whereas at least 10 species are currently recognized in South America. Of the single Middle Ameri- can species, 1214 preserved frogs, 33 skeletons, seven lots of tadpoles, and four preserved clutches of eggs have been examined. Comments: Obviously, Middle America is a peripheral part of the distribution of the Hyla leucophyllata group, which is widespread in the Amazon Basin. The greatest diversity is in the western part of the basin and on the lower slopes of the Andes, where eight nomi- nal species are found. Too little is known about the coloration in life and of the mating X 6. Fig. 90. Skull of Hyla ebraccata, K.U. No. 77686. calls of these populations to determine their taxonomic relationships. Perhaps, as sug- gested by Duellman ( 1966b ) , some of the currently recognized species are only color variants of a single species. The Middle American species, Hyla ebrac- cata, apparently is a post Pliocene invader into Middle America, where it occurs princi- pally on the humid Caribbean and Gulf low- lands. Hyla ebraccata Cope Hyla ebraccata Cope, 1874, p. 69 [holotype, A.N.S.P. No. 2079 from Machuca, Zelaya Province, Nicaragua; John F. Bransford collector], Brocchi, 1882, p. 44. Smith and Taylor, 1948, p. 84. Taylor, 1952c, p. 885. Stuart, 1963, p. 35. Duellman, 1966b, p. 267 [placed Hyla weyerae Taylor, 1954, in the synonymy of Hyla ebraccata] . Hyla leucophyllata: Boulenger, 1882a, p. 387 [part]. Gunther, 1901 (1885-1902), p. 277. Tavlor, 1942, p. 80. Hyla weyerae Taylor, 1945b, p. 633 [holotype, K.U. No. 34850 from Esquinas Forest Preserve, Las Esquinas, between Palmar and Golfito, Puntarenas Province, Costa Rica; Mrs. Albert E. Weyer collector]. Diagnosis: This is a small species char- acterized by a rather short, truncate snout, extensive axillary membrane, yellowish tan or yellow dorsum with or without dark brown markings, and uniformly yellow thighs. From the South American Hyla leucophyllata, ebrac- cata may be distinguished by the presence of an expanded white or yellow spot below the eye. The only other Middle American hylid with an extensive axillary membrane and a yellowish tan dorsum is the stream-breeding Hyla melanomma, which has a pointed snout, no transverse markings on the forearms and shanks, and usually a dorsal pattern consisting of small dark flecks. Of the other small Mid- dle American hylids having an axillary mem- brane and uniformly yellow thighs, Hyla mi- crocephala microcephala, picta, robcrtmer- tensi, and smithi have dorsolateral, longitudi- nal white stripes. Hyla rnicrocephala under- icoodi and H. phlebodes have a dorsal pattern consisting of irregular brown dashes on a tan or yellowish tan dorsum. Hyla subocularis has a black bordered yellow spot on the thigh. The only other Middle American hylids that are predominately yellow or yellowish tan are Hyla bromeliacia and sumichrasti; both lack an axillary membrane. 228 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Description : This is a small, rather broad- headed frog; males attain a maximum snout- vent length of 27.8 mm., and females reach 36.5 mm. In a sample of 25 males from Pa- cuare, Cartago Province, Costa Rica, the snout- vent length is 23.1 to 27.1 (mean, 25.1) mm.; the ratio of tibia length to snout-vent length is 0.488 to 0.566 (mean, 0.527); the ratio of foot length to snout-vent length is 0.435 to 0.472 (mean, 0.449); the ratio of head length to snout-vent length is 0.279 to 0.339 (mean, 0.311); the ratio of head width to snout-vent length is 0.301 to 0.370 (mean, 0.330), and the ratio of the diameter of the tympanum to that of the eye is 0.333 to 0.462 (mean, 0.399). Few noticeable differences exist in size and proportions from throughout the range of the species in Mexico and Central America ( table 24). The largest individuals are from the eastern part of the range in Darien Province, Panama; specimens from El Peten, Guatemala, have the relatively shortest tibia length. Except in gravid females, the head is wider than the body, and the top of the head is flat or slightly convex. In dorsal profile, the snout is truncate; in lateral profile, the snout is trun- cate and angled posteroventrally. The snout is short; the nostrils are slightly protuberant and situated about four-fifths the distance from the eyes to the tip of the snout. The canthus is rounded and indistinct; the loreal region is barely concave, and the lips are moderately thin and barely flared. A thin dermal fold extends posteriorly from the pos- terior corner of the eye to a point above the insertion of the arm; the fold obscures the upper edge of the tympanum. Only the an- teroventral edge of the tympanum bears a dis- tinct rim; the rest of the tympanum is barely discernible beneath the skin. The tympanum is posterior to the eye and separated from the eye by a distance equal to the diameter of the tympanum. The arm is moderately short and robust; the axillary membrane extends nearly to the elbow. An indistinct glandular area, oval in shape, is present in some specimens just pos- terior to the insertion of the arm on the belly. There is no dermal fold along the outer edge of the forearm; an indistinct transverse fold is present on the wrist. The fingers are short and broad and have large discs, the diameter of the disc on the third finger is usually slightly larger than the diameter of the tympanum. The subarticular tubercles are moderately large, round, and subcorneal; the distal tuber- cle on the fourth finger is bifid in nearly all specimens. The supernumerary tubercles are large, round, and present in a single row on the proximal segment of each digit; in some individuals additional supernumerary tuber- cles are present on the proximal segments of the third and fourth fingers. A large, flat, bi- furcate palmar tubercle is present. The pre- pollex is moderately enlarged; breeding males lack a horny nuptial excrescence. The fingers TABLE 24 Comparison of Sizes and Certain Proportions, with Means in Parentheses, of Adult Males of Hi/la ebraccata. Snout-vent Tibia Length/ Head Length/ Head Width/ Tympanum/ Locality N Length S-V L S-V L S-V L Eye Guatemala : Toocog ... 25 23.9-28.3 0.490-0.549 0.283-0.344 0.309-0.348 0.344-0.464 (25.9) (0.515) (0.313) (0.325) (0.392) Costa Rica: Pacuare ... 25 23.1-27.1 0.488-0.566 0.279-0.339 0.301-0.370 0.333-0.462 (25.1) (0.527) (0.311) (0.330) (0.399) Costa Rica: Rincon de Osa 25 23.8-25.6 0.514-0.580 0.301-0.345 0.317-0.349 0.282-0.452 (24.8) (0.548) (0.318) (0.311) (0.360) Panama: Tacarcuna ... 25 25.8-29.3 0.502-0.558 0.288-0.328 0.326-0.355 0.352-0.484 (27.8) (0.534) (0.306) (0.338) (0.422) 1970 DUELLMAN: HYLID FROGS 229 are about one-half webbed (fig. 91A). The web is vestigial between the first and second fingers, but extends from the middle of the penultimate phalanx of the second finger to the base of the penultimate phalanx of the third and on to the base of the penultimate phalanx of the fourth finger. The hind limbs are moderately short and slender; the ad- pressed heels overlap by about one-fourth the length of the shank. The tibiotarsal articula- tion extends to the anterior corner of the eye. A thin, flap-like tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is low, flat, and elliptical; the tubercle is barely visible from above. A minute outer metatarsal tubercle is present. The toes are long and slender; the discs are smaller than those on the fingers. The subarticular tuber- cles are moderately large, round, and sub- conical. Minute supernumerary tubercles are present on the proximal segments of all digits. The toes are about three-fourths webbed (fig. 91B). The web extends from the base of the disc of the first to the distal end of the pen- ultimate phalanx of the second and on to the base of the penultimate phalanx of the third toe; the web continues from the base of the disc of the third toe to the distal end of the antepenultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly near the level of the upper edges of the thighs. No anal sheath, as such, is present. The skin is smooth, except on the belly and ventral surfaces of the thighs where it is granular. The tongue is narrowly elliptical, about twice as long as wide, not or barely notched poste- riorly and only slightly free behind. There are usually one or two prevomerine teeth on each of the posteromedially slanting elevated processes between the small, round choanae. Of 25 males from Pacuare, Cartago Province, Costa Rica, five individuals lack prevomerine teeth, and one individual has three teeth on one side and two on the other. Most females from the same locality have three teeth on each prevomerine process. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly disten- sible. The general coloration of Hijla. ebraccata is Fig. 91. Hand (A) and foot (B) of Hijla ebrac- cata, K.U. No. 77121. x 7. pale yellow or yellowish tan with dark brown dorsal markings (pi. 49, fig. 7). When active at night, the frogs usually are pale yellowish tan with the dorsal markings barely discern- ible. By day the contrasting dorsal coloration is apparent. The thighs in all individuals are uniformly yellow or pale orange. Most of the upper arm, the inner surface of the foot, the 230 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 hands, and the feet are pale yellow. Likewise, the flanks are pale yellow and give way ven- trally to creamy white on the belly. The side of the head including the tympanum is dark brown, except tor a narrow creamy white or yellow labial stripe which in most speci- mens is broadly expanded into a noticeable subocular spot. The dorsal yellow markings on the body, forearm, and shanks, turn white by day in some individuals. Usually, in these same individuals, the brown markings are outlined by a darker brown. The iris is red- dish bronze or reddish tan with red flecks. In breeding males the vocal sac is bright yellow. In preserved specimens, the dorsal mark- ings are brown, and the dorsal ground color is creamy white or tan. The thighs lack pig- ment and the venter is creamy tan. The dorsal dark markings in Hyla ebrac- ccita usually consist of an hourglass-shaped mark that extends from the eyelids to the sacral region, where in most specimens the posterolateral corners of the hourglass are con- fluent with the dark markings on the side. The shape of this dorsal mark is highly variable; in each population sampled throughout the range in Middle America various permutations of the pattern have been observed. In the northern part of the range, in Mexico and Guatemala, all individuals have some form of the dark dorsal markings, except one speci- men from Teapa, Tabasco, which has a uni- form tan dorsum. In several individuals the hourglass is narrowed medially, and in some the anterior part of the mark is separated from the posterior part. In other individuals, the posterior part of the mark is further reduced or fragmented, so that the only apparent dor- sal mark is a triangle in the occipital region (fig. 92). In Costa Rica and western Panama, numerous individuals have the dorsal mark- ings reduced to spots or flecks, and some indi- viduals are uniform yellowish tan above (pi. 49, fig. 8). The highest incidence of plain (unmarked) individuals is on the Pacific low- lands of Puntarenas Province, Costa Rica, where approximately half of the specimens lack dorsal markings. Although the frogs from southern Costa Rica and western Panama are especially variable, the "normal" pattern is prevalent in all of the populations sampled (table 25). Tadpoles: Ten hatchlings from Puerto Viejo, Heredia Province, Costa Rica, have total lengths of 5.7 to 6.1 (mean, 5.91) mm., and 11 hatchlings from Toocog, El Peten, Guatemala, have total lengths of 4.5 to 5.0 (mean, 4.77) mm. The largest tadpole ex- amined is an individual in developmental stage 40 having a body length of 11.0 mm. and a total length of 31.2 mm. A typical tad- pole in developmental stage 36 from Puerto Viejo, Heredia Province, Costa Rica, has a total length of 29.4 mm. and a body length of 9.6 mm. The body is as wide as deep. In dorsal profile the snout is bluntly rounded; in lateral profile it is slightly pointed. The nos- trils are rather small and are situated dorso- laterally at a point about equidistant between the snout and the eyes. The eyes are large and directed laterally. The spiracle is sinistral and lies just posteroventral to the eye; the anal tube is long and median. The tail is xiphi- cercal, and the caudal musculature is moder- ately deep anteriorly but slender distally. The fins are deepest at about midlength of the tail. The small, terminal mouth lacks teeth. There is no upper lip, and the lower lip is replaced by a heavy fleshy fold that bears papillae-like protuberances. The upper beak is shallow and forms a broad, uniform arch; the lower beak is massive. Both beaks bear fine serrations (fig. 93). The dorsum is dark brown mottled with tan which tends to form a chevron-shaped mark with the apex at the mouth. Laterally, the pigment is interrupted by a broken white stripe extending from the mouth posteriorly below the eye along the body and onto the tail. The venter is white medially and mot- tled with gray peripherally. The caudal mus- culature is marked with a longitudinal gray stripe. The caudal fins are heavily pigmented with gray or black blotches. The pale areas on the caudal fin are rose-red. The iris is bronze peripherally and red centrally. In preservative, the tadpoles are yellowish brown on the dorsal part of the body and the caudal fin. A dark brown stripe extends from the tip of the snout to the eye; a stripe or row of dark spots is evident on each side of the caudal musculature. The sides of the body- are gray with brown reticulations. The venter is creamy white. The caudal fins are trans- 1970 DUELLMAN: HYLID FROGS 231 Fig. 92. Variation in the dorsal color pattern in Hula cbraccata. A. KU No. 57292. B. K.U. No. 57295. C. K.U. No. 57277. D. K.U. No. 57287. E. K.U. No. 57291. F. K.U. No. 77050. G. K.U. No. 77052. H. K.U. No. 77044. I. K.U. No. 77077. J. K.U. No. 77073. A-E from Toocog, El Peten, Guatemala; F-J from Achiote, Colon, Panama. X 3. TABLE 25 Geographical Distribution of Color Pattern Variants in Hyla ebraccata. Locality Hourglass Triangle Spotted Plain Valle Naeional, Oaxaca, Mexico 19 Teapa, Tabasco, Mexico 13 2 1 Toocog, El Peten, Guatemala 47 6 Turrialba, Cartago, Costa Rica 87 Pacuare, Cartago, Costa Rica 48 Moravia, Cartago, Costa Rica 21 Suretka, Limon, Costa Rica 45 6 14 Tilaran, Guanacaste, Costa Rica 50 3 15 Palmar-Golfito, Puntarenas, Costa Rica 7 6 Rincon de Osa, Puntarenas, Costa Rica 23 2 4 Achiote, Colon, Panama _ 46 16 15 Cerro La Campana, Panama, Panama 16 3 Taeareuna-Rio Mono, Darien, Panama 63 Totals 485 8 30 55 Total 19 16 53 87 48 21 65 68 13 30 77 19 63 579 232 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 /^ Fig. 93. Mouth of a tadpole of Hyla ebraccata, K.U. No. 104130. x 40. parent with dark brown blotches or vertical bars (fig. 94). Tadpoles from Toocog, El Peten, Guate- mala, were more colorfully marked in life. A black stripe was present on each side of the body and on the top of the head; a black band was present on the anterior part of the tail and another on the posterior part. The body and the anterior part of the tail were creamy yellow; a dark red vertical band was present between the black bands on the tail. Tadpoles from Tacarcuna, Darien Province, Panama, had red on the posterior part of the caudal musculature and fins; otherwise they were marked like those from Costa Rica and Guatemala. Mating Call: The call of Hyla ebraccata is a moderately low insect-like "creeek" fol- lowed, or not, by one or more secondary notes. The primary note is a single, pulsed note, whereas the secondary notes are paired. The repetition rate of the secondary notes is 210 to 429 (mean, 311.5) notes per minute. In a sample from Toocog, El Peten, Guatemala, the pulse rate is 93 to 102 (mean, 97.2) pulses per second. The duration of the primary notes in this population are 0.12 to 0.18 (mean, 0.16) of a second and that of the secondary notes is 0.02 to 0.05 (mean, 0.03) of a second. The dominant frequency of the primary note varies from 2300 to 2650 ( mean, 2504 ) cycles per second. Each primary note has 11 to 17 (mean, 14.2) pulses (pi. 29, fig. 1). Some geographic variation is evident in the call of Hyla ebraccata (table 26). Record- ings of individuals from Guatemala, the Carib- bean slopes of Costa Rica, and the Pacific lowlands of Costa Rica, plus the data given for the species in the Canal Zone given by Fouquette ( 1960b ) show that there is an in- crease in the duration of the primary note from north to south and an increase in the dominant frequency. A comparison of the characteristics of the calls from Guatemala with those from Costa Rica show that the latter have a slower pulse rate. In Guatemala, approximately 70 per cent of the calls were compound, that is, each call was composed of a primary plus one or more secondary notes. On the Pacific lowlands of Costa Rica, only 10 per cent of the calls are compound, whereas in the Canal Zone, Fouquette (1960b) found that 54 per cent of the calls were com- pound. Fouquette (1960b) described the existence of a high primary note that is emit- ted by some individuals from the Canal Zone. Occasional frogs were heard to emit high notes in Costa Rica and in Panama, but high notes were not heard in Guatemala. Natural History: Hyla ebraccata is an inhabitant of primary humid tropical forest; the species also occurs in cut-over forest and in some places in areas where most of the forest has been removed. Throughout most of its range the species lives in areas receiving rainfall throughout most of the year; the breeding season apparently is dependent upon moderately heavy to heavy rains. For exam- ple, the breeding season is closely correlated with the rainy season extending from June through September in southern Mexico and Guatemala and is more extensive in lower T'?:iZ?'zr!&mrr Fig. 94. Tadpole of Hyla ebraccata, K.U. No. 104130. x 3. 1970 DUELLMAN: HYLID FROGS 233 TABLE 26 Geographic Variation in Mating Calls, with Means in Parentheses, of Hyla ebraccata. Locality N Guatemala: El Peten ..... 9 Costa Rica: Caribbean ... 6 Costa Rica: Pacific 9 Panama: Canal Zone" 19 Duration of Primary Note Pulse Rate (pulses per second) Dominant Frequency (cps) 0.12-0.18 (0.16) 0.16-0.23 (0.20) 0.16-0.24 (0.19) 0.16-0.29 (0.21) 93-102 (97) 88-95 (92) 90-96 (91) 2300-2650 (2504) 2520-2600 (2570) 2690-2940 (2790) 2500-3450 (3064) " From Fouquette (1960b, p. 491). Central America, for example, in the Canal Zone, where breeding takes place from May through January. In the wet Pacific lowlands of the Golfo Dulce region in Costa Rica, breeding begins as early as March. Males of Hyla ebraccata usually call from the leaves of emergent herbs or from the leaves of bushes and trees closely overhanging the water in temporary ponds in, or at the edge of, forest. Observations on small choruses in- dicate that individual males answer to one another's call. The chorus structure seems to be organized into duets. However, in large choruses, this organization is either non- existent or is not apparent. In the breeding season, the frogs secret themselves by day amidst herbaceous plants growing in or around the breeding ponds. Individuals have been found in bromeliads both in the rainy and in the dry seasons. The eggs are deposited on the dorsal sur- faces of leaves, usually of herbaceous plants, above the water. All eggs are in a single layer on the leaf. The external membranes are bare- ly visible, for the eggs consist of a single co- herent mass. Eggs in the yolk plug stage have diameters of 1.2 to 1.4 mm. Seventeen masses of eggs were found at Toocog, El Peten, Guatemala, between June 30 and July 2, 1960. These masses contained from 24 to 76 ( mean, 44) eggs. The jelly is extremely viscous and tacky to the touch. At time of hatching, the jelly becomes less viscous; the tadpoles wriggle free of the jelly and continue to wiggle across the surface of the leaf until they reach the edge and drop into the water. Hatchling tad- poles are active swimmers and have only a small amount of yolk. Larger tadpoles inhabit shallow weedy parts of ponds and take refuge in dense aquatic vegetation. Remarks: Duellman (1966b) showed that Hyla weyerae Taylor is nothing more than a color variant of Hyla ebraccata Cope. He con- cluded that only one species is involved, be- cause both color variants were found breeding in the same pond the same night and that no differences were discernible in the mating call. Furthermore, the "weyerae" color pattern ( pi. 49, fig. 8) is present on both the Caribbean and Pacific lowlands of lower Central Amer- ica and in the Gulf lowlands of Mexico. Dunn (1931b, and 1933) and Breder (1946) used the name Hyla leucophyllata (Bereis) for Panamanian frogs currently as- signed to Hyla ebraccata. On the basis of our present knowledge of this variation within spe- cies in the Hyla leucophyllata group, I am convinced that leucophyllata and ebraccata and not conspecific. Hyla ebraccata differs from leucophyllata in having a white or yellow labial mark expanded below the eye; the lips of Hyla leucophyllata are uniform brown. Etymology: The specific name ebrac- cata is derived from the Latin bracatus mean- ing "wearing trousers" and from the Latin pre- fix e-\ the name means literally "without trou- sers" and refers to the unpigmented condition of the thighs. Distribution: Hyla ebraccata inhabits the Caribbean and Gulf lowlands of southern Mexico, exclusive of the Yucatan Peninsula, but occurs in British Honduras and the south- 234 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 em part of El Peten, Guatemala. The species has not been found in Honduras, and only two specimens are known from Nicaragua. The species is abundant on the Caribbean lowlands of Costa Rica and Panama eastward to the Canal Zone, where it crosses onto the Pacific lowlands of eastern Panama and the Choco of Colombia. A disjunct population occurs in the Golfo Dulce region in the Pacific lowlands of Costa Rica (fig. 95). Most of the localities from which this species is known are on the lowlands or low foothills, but at some places, Hylo ebraccata occurs at moderate elevations. For example, it occurs at 800 meters at La- guna, Darien Province, Panama, and at Ti- laran, Guanacastc Province, Costa Rica; the highest known elevation is 1200 meters at Moravia de Turrialba, Cartago Province, Costa Rica. See Appendix 1 for the locality records of the 1258 specimens examined. The Hijla parviceps Group Definition: The members of this group are small species; males attain a maximum snout-vent length of 24 mm. and females, 31 mm. The dorsum is variously marked with dark brown; a creamy white canthal stripe and subocular marks are usually present. The thighs have conspicuous yellow or orange spots bordered by brown or black. Females characteristically have a broad pale tan, creamy yellow, or white dorsolateral stripe. Dermal folds and appendages are lacking on the limbs; a short axillary membrane is pres- ent. Males have a single, median, subgular vocal sac and lack nuptial excrescences on the pollices. The cranial elements are weakly os- 84° 78° 96° 90° Fig. 95. Distribution of Hijla ebraccata. 1970 DUELLMAN: HYLID FROGS 235 sified; a large frontoparietal fontanelle is pres- ent (fig. 96). The quadratojugal is greatly reduced and not in contact with the maxillary; the anterior arm of the squamosal is short and does not extend to the maxillary. The nasals are relatively small, rectangular, separated medially, but in contact with the sphen- ethmoid. Prevomerine teeth are present. The tadpoles have xiphicercal tails and terminal mouths lacking teeth. The mating call con- sists of a short trill. The haploid number of chromosomes is 15 (known in //. rondoniae and subocularis) . Composition: Five nominal species be- long to this group. Only one species, Hyla subocularis, occurs in Central America; the other species are South American. Of the single Central American species, 62 preserved specimens, three skeletons, and one lot of tad- poles have been examined. Comments: Of the eight known species in this group, Hyla parviceps is distinctive in hav- ing a dark gray or black belly and a bright orange spot on the ventral surface of each shank. The other species lack the orange spot, have a creamy-white venter, and have more distinctive subocular markings. Of the latter Fig. 96. Dorsal (A) and lateral (B) views of the skull of Hyla subocularis, K.U.No. 77690. X 7. group, Hyla luteocellata Roux is known only from northern Venezuela, and H. grandisonae Goin is known only from Guyana, whereas Hyla rondoniae Bokermann and H. boker- manni Goin are known from the upper Ama- zon Basin, the region inhabited by Hyla parvi- ceps Boulenger. Hyla bokermanni, rondoniae, and parviceps occur sympatrically in Napo Province, Ecuador. Hyla microps occurs in eastern Brasil, and H. carnifex is known from the Pacific slopes of Ecuador. Hyla subocularis apparently is a post- Pliocene invader in Central America from a diverse and widely distributed group in South America. The affinities of the Hyla parviceps group seem to be with the Hyla leucophyllata group and more distantly with the Hyla mi- crocephala group. Hyla subocularis Dunn Hyla subocularis Dunn, 1934, p. 2 [holotype, A.M.N.H. No. 41117 from the Rio Chucunaque at the first creek above the Rio Tuquesa, Darien, Panama; Charles M. Breder, Jr. collector]. Diagnosis: This small species differs from all other Middle American hylids by having the thighs unpigmented except for a bright yellow spot bordered by black and by having the following markings on the head; a creamy white or creamy yellow vertical, narrow, ros- tral stripe connected to a narrow stripe which is continuous along the edge of the eyelid with a stripe above the tympanum, and two vertical white or yellow bars from the eye to the edge of the lips. Hyla parviceps differs from sub- ocularis by having black thighs with creamy yellow streaks, a dark venter, one or two small yellow labial spots, and by lacking the narrow stripes on the head. Hyla rondoniae resem- bles subocularis, but differs in having brown thighs with two creamy yellow round spots. See the section on Remarks for comments on Hyla bokermanni and luteocellata. Description: This is a small frog; males attain a maximum snout-vent length of 23.1 mm. (mean, 25 specimens from Tacarcuna, Darien, Panama, 21.7 mm.), and females reach 26.1 mm. (mean, six specimens, 24.8 mm. ) . In the sample of 25 males from Tacar- cuna, the ratio of tibia length to snout-vent length is 0.481 to 0.552 (mean, 0.508); the ratio of foot length to snout-vent length is 236 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 0.381 to 0.450 (mean, 0.426); the ratio of head length to snout-vent length is 0.290 to 0.336 (mean, 0.319); the ratio of head width to snout-vent length is 0.316 to 0.341 (mean, 0.327), and the ratio of the diameter of the tympanum to that of the eye is 0.259 to 0.440 (mean, 0.366). Females have proportionately larger heads and larger tympani. In the sam- ple of six females from Tacarcuna, the ratio of head length to snout-vent length is 0.314 to 0.335 (mean, 0.327); the ratio of head width to snout- vent length is 0.330 to 0.344 (mean, 0.340), and the ratio of the diameter of the tympanum to that of the eye is 0.355 to 0.481 (mean, 0.413). The head is about as wide as the body, and the top of the head is flat or slightly convex. In dorsal and lateral profiles the snout is trun- cate; in lateral profile the snout slopes slightly posteroventrally. The snout is relatively short; the nostrils are barely protuberant and are situated about three-fourths the distance from the eyes to the tip of the snout. The canthus is rounded, but distinct; the loreal region is barely concave, and the lips are moderately thin and barely flared. There is no distinct dermal fold extending posteriorly from the eye. The tympanum is rather indistinct, situ- ated posterior to the eye, and separated from the eye by a distance equal to about one and one-half times the diameter of the tympanum. The arm is moderately long; the forearm is more robust than the upper arm. An ab- breviated axillary membrane is present. There is no dermal fold along the outer edge of the forearm, but a faint transverse fold is present on the wrist. The fingers are short and broad and have relatively large discs; the diameter of the disc on the third finger is about equal to the diameter of the tympanum. The sub- articular tubercles are relatively small and round; the distal tubercle on the fourth finger is bifid in about one-third of the specimens. The supernumerary tubercles are small, round, indistinct, and arranged in a single row on the proximal segments of the second, third, and fourth fingers. The prepollex is slightly en- larged; breeding males lack horny nuptial excrescences. The fingers are about one-third webbed (fig. 97A). The webbing is vestigial between the first two fingers but connects the base of the penultimate phalanx of the second finger to the base of the antepenultimate pha- lanx of the third and continues from the mid- dle of the antepenultimate phalanx of the third to the base of the penultimate phalanx of the fourth finger. The hind limbs are moder- ately short and robust; the adpressed heels barely overlap. The tibiotarsal articulation extends to the anterior corner of the eye. There is no tarsal fold. The inner metatarsal tubercle is low and elliptical, and the outer metatarsal tubercle is absent. The toes are moderately long and slender; the discs are slightly smaller than those of the fingers. The subarticular tubercles are small and round; a few supernumerary tubercles are present on the proximal segments of all but the first toe. The toes are about two-thirds webbed (fig. 97B ) . The webbing connects the first two toes at the bases of the penultimate phalanges; the web extends from the middle of the penulti- mate phalanx of the second toe to the base of the antepenultimate phalanx of the third, from the middle of the penultimate phalanx of the third to the middle of the antepenultimate phalanx of the fourth and on to the middle of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally near the level of the upper edges of the thighs. The anal sheath is short and broad. The skin is moderately granular on the belly and ventral surfaces of the thighs; elsewhere it is smooth. A thin thoracic fold is present. The tongue is ovoid, slightly longer than wide, very shallowly notched anteriorly and posteriorly, and barely free behind. In males, there are two or three (mean, 2.4) and females, three to five ( mean, 3.4 ) prevomerine teeth situated on distinct transverse elevations between the posterior margins of the small, round choanae. The vocal slit extends from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Hyla subocalaris is yellowish tan with brown dorsal and lateral markings and one or more black-bordered yellow spots on the anterior or anterodorsal surfaces of the thighs (pi. 49, fig. 6). The dor- sum is yellowish tan or pale brown, usually with an X-shaped mark centered in the scapu- lar region; the anterior arms of the X extend onto the eyelids, and the posterior arms are 1970 DUELLMAN: HYLID FROGS 237 Fig. 97. Hand (A) and foot (B) of Hyla sub- ocularis, K.U. No. 77355. x 7. continuous, or not, with a pair of short brown streaks in the sacral region. Usually a short middorsal brown streak is present posterior to the sacrum. The dorsal surfaces of the arms, the shanks, and the feet are pale tan with brown transverse bars, usually two or three bars on the forearm and four or five bars on the shank. In some individuals, dark brown or black flecks are scattered on the dorsum of the body, forearm, and shanks. The side of the head and anterior part of the flanks are dark brown. A creamy yellow vertical ros- tral stripe connects with a similarly colored canthal stripe, which extends along the outer edge of the eyelid and continues posteriorly above the insertion of the forearm and fades into the dorsal coloration in the mid-flank re- gion. In females, the stripe is widened above the forearm and extends posteriorly to the mid-flank region as a broad, creamy tan stripe. Usually two, but sometimes only one, vertical, creamy white or creamy yellow suborbital bars are present. In most individuals both bars reach the orbit, and in some specimens, the bars are expanded at the edge of the lip. In a few individuals the bars are fused ven- trally to form a short labial stripe. The proxi- mal surfaces of the upper arm, the posterior parts of the flanks, and the thighs lack pig- ment, except for distinctive markings on the thighs. Usually one, but sometimes two, bright yellow spots are present on the antero- dorsal surfaces of the thighs; these spots are bordered with black pigment, which in some specimens forms a reticulate pattern on the posterior surfaces of the distal part of the thighs. In most specimens, there is a small yellow, black-bordered spot in the groin and a dark brown or black mark at the insertion of the hind limb. The belly is white; the chin and throat are creamy white. In some speci- mens, brown flecks or spots are present along the edge of the lower lip. The ventral sur- faces of the limbs and the webbing on the hands and feet lack pigment. The iris is pale silver peripherally and rose-pink medially. The palpebral membrane is unpigmented. In preservative, the dorsum is grayish brown with dark brown markings. The dorso- lateral stripe in females is creamy white and the narrow stripes on the head in both sexes are creamy white. The distinctive markings on the thighs are pale tan or white surrounded by black. The venter is creamy white. Tadpoles: A single tadpole in develop- mental stage 37 has a total length of 27.5 mm. and a body length of 9.1 mm. The body is broader than deep. In dorsal profile, the snout is broad and bluntly rounded, in lateral profile it is round. The eyes are large, widely separated, and directed laterally. The nostrils are directed anterolaterally at a point about two-thirds of the distance from the eyes to the snout. The opening of the sinistral spir- acle is directed posteriorly at a point below the midline and about two-thirds of the dis- tance from the snout to the posterior end of 238 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fie. 98. Tadpole of Hyla subocularis, K.U. No. 116784. x 5. the body. The anal tube is dextral and short. The caudal musculature is slender and extends well beyond the end of the fins so as to form a xiphicercal tail. The dorsal fin is slightly deeper than the ventral fin, does not extend onto the body, and at midlength of the tail is half again as deep as the caudal muscula- ture (fig. 98). The body and tail are black with a dorso- lateral tan stripe on the body and irregular tan vertical marks on the tail. Small bronze spots are present on the venter. The iris is orange-red with black flecks. In preservative, the coloration remains the same, except for the loss of the color of the iris. The mouth is small and terminal. The upper lip is bare, and the rest of the mouth is bordered by a single irregular row of large blunt papillae. The beaks are massive and rounded with fine serrations. Teeth are ab- sent (fig. 99). Mating Call: The call of Hyla subocu- laris is a short trill. Two recordings obtained at Tacarcuna, Darien Province, Panama, show that there is a call repetition rate of three to 20 seconds. The duration of the trill is 0.53 of a second, and the trill has a pulse rate of 43 pulses per second and a dominant fre- 'JO-O'- Fig. 99. Mouth of tadpole of Hyla subocularis, K.U. No. 116784. x 45. quency of 2200 cycles per second (pi. 29, fig. 2). Natural History: Hyla subocularis has been found in areas of humid forest. At Tacarcuna, Darien Province, Panama, the spe- cies was found breeding in July, 1963. Males were calling from leaves of low trees and bushes overhanging the pond and from hori- zontal leaves of emergent herbaceous vegeta- tion in the pond. Clasping pairs were found on emergent vegetation. Unlike Hyla ebrac- cata, which was abundant in the ponds where subocularis was breeding, the latter species apparently does not spend the day hidden amidst vegetation in the pond. At dusk, many individuals of Hyla subocularis were observed moving towards the pond on several consecu- tive nights when there did not seem to be any increase in breeding activity in this species. A recently metamorphosed young was found on an herb next to a pond at Laguna, Darien Province, on July 6, 1963; another was found on a bush above a pond at Tacar- cuna, on July 13. These specimens have snout- vent lengths of 11.5 and 11.9 mm. In life, the dorsum was pale bronze-tan; yellow and black pigment were not present on the thighs. The iris was silver peripherally and red medially. Charles W. Myers obtained two tadpoles of this species on November 25, 1965, in shal- low water in a swamp forest about 7 kilometers upstream on the Rio Ucurganti from the Rio Chucunaque in Darien Province, Panama. The tadpoles were resting on leaves on the bottom. The caudal musculature posterior to the fins was observed to wiggle conspicuously. One tadpole was preserved on December 3, 1965, in developmental stage 37 (figs. 98 and 99), and the other metamorphosed on December 6. Remarks: Breder (1946, p. 417) listed three specimens in addition to the holotype. One of these, A.M.N.H. No. 51777 from 'Rio 1970 DUELLMAN: HYLID FROGS 239 Chucunaque is a juvenile Hyla subocularis- A.M.N.H. No. 51784 is a young Hyla rosen- bergi, and A.M.N.H. No. 51786 is a series of juvenile Eleutherodactylus and recently meta- morphosed hylids, none of which seem to be Hyla subocularis. On the basis of observations of living indi- viduals in the field, I suspect that Hyla boker- manni and H. subocularis are conspecific. Goin ( 1960c) named Hyla bokermanni on the basis of an immature female from Tarauaca, Acre, Brasil, and Cochran and Goin ( 1970 ) recorded the species from Rio Manso, Cordoba, Colom- bia. I have examined four of the specimens (C.J.G. Nos. 2355-2358) from the Rio Manso and find that they are indistinguishable from Panamanian Hyla subocularis. I collected in- dividuals conforming to descriptions given by Goin ( 1960c) at Santa Cecilia, Napo Province, Ecuador. In life these individuals had bright yellow, black-bordered spots on the thighs, the same pattern of creamy yellow lines on the head as noted in Panamanian Hyla subocu- laris, and an iris that was red medially and silver peripherally. The frogs at Santa Cecilia were readily distinguished from Hyla parvi- ceps, which lacks the rostral, canthal, and su- pratympanic stripes and black-bordered yel- low spots on the thighs and has black limbs with a bright orange spot on the ventral sur- face of the shank. The third species in the parviceps group occurring at Santa Cecilia is Hyla rondoniae, described by Bokermann (1963) from Rondonia, Brasil. In this species the markings on the head are like those in Hyla subocularis, but the coloration of the thighs differs; the thighs are brown with usu- ally two creamy yellow spots (fused into an elongate mark in some individuals) on the anterodorsal surface of the thigh. The call of Hyla rondoniae is similar to that of subocu- laris in structure; analysis of one recording obtained at Santa Cecilia reveals that each note has a duration of 0.44 of a second, a pulse rate of 35 pulses per second, and a dominant frequency of 4200 cycles per second. Thus the call is slightly shorter and more slowly pulsed, but noticeably higher pitched than that of Hyla subocularis. Etymology: The specific name subocu- laris is derived from the Latin sub, meaning under, and ocidaris, meaning of the eyes, and refers to the distinctive vertical creamy yellow bars beneath the eyes. Distribution: Hyla sidwcularis is known from the lowlands to elevations of about 800 meters in the Chucunaque-Tuira Basin (Pa- cific drainage), in Darien Province, Panama, and the Rio Manso, Departamento Cordoba, Colombia (fig. 100). See Appendix 1 for the locality records of the 66 specimens examined. The Hyla albomarginata Group Definition: The members of this group are medium-sized tree frogs; males attain a maximum snout-vent length of 54 mm. and females, 60 mm. The dorsum is green ( creamy white or pale yellow in preservative) with scattered dark flecks and/or small white spots. The webbing and/ or hidden surfaces of the hind limbs are pink or red. The palpebral membrane is clear. The fingers are about half, and the toes about three-fourths webbed. A tarsal fold is present, and some species have 78° 9° go J) y^ ry*^ \ r' \ • U. \ \ V 8° i ^ V • ^ • \ / / ( X f \ y.y ) j 0 20 50 8° / KILOMETERS 78° Fig. 100. Distribution of Hyla subocularis. 240 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 a dermal flap on the heel. An axillary mem- brane is absent. Males have a single, median, subgular vocal sac and a protruding prepollex, which does not bear a horny nuptial excres- cence but through which a prepollical spine projects in some species. The skull is only moderately ossified; an ovoid frontoparietal fontanelle is present (fig. 101). The sphen- ethmoid is moderately well ossified, whereas the nasals are poorly ossified, long, slender elements, which are narrowly separated me- dially and have a cartilaginous connection to the sphenethmoid. The nasals bear slender maxillary processes which do not articulate with the maxillaries. The premaxillaries are delicate and have short alary processes. The squamosal is in bony contact with the crista parotica, and the anterior arm of the squa- mosal extends no more than half of the dis- tance to the maxillary. The prevomers are not completely ossified anteriorly but have well-developed angular dentigerous processes (fig. 101). The palatines and parasphenoid are delicate, but the pterygoids are robust and articulate with the prootics and broadly with the maxillaries. The known tadpoles are pond types and have robust bodies and moderately large mouths with two upper and four lower rows of teeth. The known mating calls con- sist of a series of short, well-modulated notes. The haploid number of chromosomes is 12 (known only in Hyla rufitela). Composition: Nine species presently are included in this group; only one species ( Hyla rufitela) occurs in Central America. Of the others, Hyla albomarginata is widespread in the tropics of South America east of the Andes, pellucens occurs on the Pacific lowlands of Ecuador, albopunctulata occurs in the upper Amazon Basin, and five species (albofrenata, albolineata, albosignata, musica, and prasina) occur in southeastern Brasil. Eighty-three pre- served frogs, one skeleton, nine lots of tad- poles, and one preserved clutch of eggs of the Middle American species have been exam- ined. Comments: This predominantly South American group possibly is related to the Hyla granosa group; both groups have angled dentigerous processes of the prevomers, pro- jecting prepollical spines, and a green dorsum. Two other South American groups — the Hyla Fig. 101. Dorsal (A) and ventral (B) views of the skull of Hyla rufitela, K.U. No. 77662. x 5. boons group and the Hyla geographica group — also have projecting prepollices and strongly angular dentigerous processes of the prevo- mers; members of those groups are medium to large in size and have a tan or brown dorsum. The relationships of these widespread South American groups are obfuscated by a dearth of information on tadpoles, life histories, and behavior. Hyla rufitela Fouquette Hi/la albomarginata: Boulenger, 1882a, p. 356. Guntlier, 1901 (1885-1902), p. 284. Taylor, 1952c, p. 893. 1970 DUELLMAN: HYLID FROGS 241 Hilla rufitela Fouquette, 1961a, p. 595 [holotype, F.M.N.H. No. 13053 from Taylor Swamp, Barro Colo- rado Island, Canal Zone, Panama; Karl P. Schmidt collector]. Diagnosis: This medium-sized green frog has red webs and a projecting propollex, a combination of characters that distinguishes it from all other Middle American hylids. Hijla loquax and //. pseudopuma infucata have red webbing but lack a projecting prepollex; fur- thermore, both of those species are brown or gray dorsally. Other species of Middle Ameri- can hylids having projecting prepollices differ from rufitela in a variety of characters — Plec- trohyla lacks red color and has little webbing on the hand; the Hijla boans group has no red but has dark reticulations or vertical bars on the flanks and thighs, and the Hula miliaria group has extensive dermal fringes on the limbs and fully webbed hands and feet. Description: Males of this medium-sized species attain a maximum snout-vent length of 49.2 mm., and females reach 52.6 mm. In a series of 25 males from Barro Colorado Island and Achiote, Panama, the snout-vent length is 41.2 to 49.2 (mean, 46.2) mm.; the ratio of tibia length to snout-vent length is 0.482 to 0.558 (mean, 0.521); the ratio of foot length to snout-vent length is 0.359 to 0.418 (mean, 0.391 ) ; the ratio of head length to snout-vent length is 0.333 to 0.368 (mean, 0.356); the ratio of head width to snout-vent length is 0.333 to 0.362 (mean, 0.349), and the ratio of the diameter of the tvmpanum to that of the eye is 0.462 to 0.63S (mean, 0.546). Two fe- males from the same area have snout-vent lengths of 49.6 and 52.6 mm. They differ from the males only by having slightly larger tym- pani; the ratio of the diameter of the tym- panum to that of the eye is 0.510 and 0.652. The head is slightly narrower than the body, and the top of the head is flat. In dor- sal profile, the snout is acutely rounded but truncate terminally; in lateral profile, the snout is rounded above and slightly posteroventrally inclined below. The snout is long; the slightly protuberant nostrils are situated at a point about five-sixths of the distance from the eyes to the tip of the snout. The canthus is an- gular, and the loreal region is noticeably con- cave; the lips are moderately thick and barely flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, and down- ward to a point above the insertion of the arm. The fold obscures the upper edge of the tym- panum, which otherwise is distinct and sepa- rated from the eye by a distance slightly less than the diameter of the tympanum. The arms are moderately short and robust; an axillary membrane is absent. There is no row of tubercles on the ventrolateral edge of the forearm, but a weak transverse dermal fold is present on the wrist. The fingers are rather short and robust and bear moderately large discs; the width of the disc on the third finger is approximately equal to the diameter of the tympanum. The subarticular tubercles are moderate in size and subcorneal; the distal tubercle on the fourth finger is weakly bifid in some individuals. No distinct supernumer- ary tubercles are evident, and a true palmar tubercle is absent. The prepollex is moderate- ly enlarged and in males is strongly protuber- ant; in some males a spine projects from the tip of the prepollical process. There is no nup- tial excrescence. The fingers are about one- half webbed (fig. 102A). The webbing is ves- tigial between the first and second fingers and extends from the distal end of the penultimate phalanx of the second to the distal end of the penultimate phalanx of the third and on to the base of the disc of the fourth finger. The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fifth of the length of the shank. The tibiotarsal articulation extends to a point be- tween the eye and nostril. Two or three small tubercles and a thin transverse dermal fold are present on the heel. The tarsal fold is weak, present only distally, or not evident at all. The inner metatarsal tubercle is long, low, flat, elliptical, and distinctly visible from above. A small subcorneal outer metatarsal tubercle is evident in some specimens. The toes are moderately long and slender and bear discs that are somewhat smaller than those on the fingers. The subarticular tubercles are rather large and round; the supernumerary tubercles are small and for the most part, in- distinct. The toes are about three-fourths webbed (fig. 102B). The webbing extends from the base of the disc of the first toe to the base of the penultimate phalanx of the second, from the base of the disc of the second 242 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 to the distal end of the antepenultimate pha- lanx of the third, from the base of the disc of the third to the base of the penultimate pha- lanx of the fourth and on to the base of the disc of the fifth toe. Fig. 102. Hand (A) and foot (B) of Hyla rufitela, K.U. No. 108855. x 4.5. The anal opening is directed posteriorly at the upper level of the thighs. A short, broad anal flap is present. A pair of vertical dermal folds and numerous tubercles are present be- low the anal opening. The skin on the chest, belly, and proximal posteroventral surfaces of the thighs is granular, elsewhere the skin is smooth. The tongue is elongate, widest an- teriorly, shallowly notched or not behind, and not free posteriorly. The dentigerous pro- cesses of the prevomers are long anteromedi- ally inclined, narrowly separated ridges be- tween the large triangular choanae. In many individuals, the anteromedial part of each dentigerous process is angled to lie in a trans- verse position. Males have nine to 12 teeth on each process and a total of 18 to 23 ( mean, 21.3) prevomerine teeth; females have 10 to 12 teeth on each process and a total of 21 to 23 (mean, 22.0) prevomerine teeth. The vocal slits are long and extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and only moderately distensible. The general coloration of Hyla rufitela con- sists of a green dorsum with darker flecks and occasional white spots and red webbing (pi. 50, fig. 1). The dorsal surfaces of the body and limbs are green with small black or brown flecks and small silvery white spots. The flanks are yellowish olive, and the axilla and groin are pale blue or bluish green. The anterior and posterior surfaces of the thighs are pale green, except that usually the distal half of the posterior surfaces of the thighs is tomato red. The webbing on the hands and feet is red. A greenish white stripe is present on the ven- trolateral edge of the forearm. The throat and ventral surfaces of the limbs are pale green, and the belly is creamy yellow medially and greenish white laterally. The iris is silvery bronze. Little variation occurs in coloration. In some individuals, a faint greenish white stripe is present on the outer edge of the foot or on the supratympanic fold. The red area on the posterior surfaces of the thighs varies from a small dash of red distally to nearly covering the entire posterior surface. In preservative, the dorsum is creamy tan with many small brown flecks; in some indi- viduals the flecks are coalesced into small 1970 DUELLMAN: HYLID FROGS 243 spots. The flanks and ventral surfaces are creamy white. In some specimens preserved for five years, the red is still evident on the posterior surfaces of the thighs and on the web. Tadpoles: A series of tadpoles is available from Barro Colorado Island, Panama and from Golfito and 4.5 kilometers west of Rincon de Osa, Puntarenas Province, Costa Rica. The largest tadpole from the latter locality is in developmental stage 40 and has a total length of 57 mm. A typical tadpole in developmental stage 37 has a body length of 19.1 mm. and a total length of 54.8 mm. The body is robust and wider than deep. In dorsal profile, the body is truncate posteriorly, and the snout is rounded; in lateral profile the snout slopes anteroventrally from the eyes to a round tip. The eyes are moderately large, widely sepa- rated, and directed dorsolaterally. The nostrils are directed anterolaterally at a point midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posterodorsally at a point just below the mid- line about two-thirds of the distance from the tip of the snout to the posterior edge of the body. The anal tube is long and dextral. The caudal musculature is rather slender and ex- tends nearly to the tip of the pointed tail. The dorsal fin is high, deepest slightly anterior to the midlength of the tail, and not extending on to the body. The ventral fin is relatively shallow and deepest at a point about two- thirds of the length of the tail. At midlength of the tail, the depth of the caudal musculature is about equal to the depth of the ventral fin but noticeably less than the depth of the dor- sal fin (fig. 103). The body is olive-tan with green and tan lichenous markings on the flanks. The belly is white with silvery flecks. The caudal muscu- lature is orange-tan with dark brown markings. The iris is bronze. In preservative, the dorsum is mottled tan and dark brown with overlying small dark brown flecks. The venter lacks pig- ment. The caudal musculature is creamy tan. Numerous small round blotches are present on the caudal musculature. The dark pigment tends to form transverse bands on the dorsum of the musculature. Small brown flecks and reticulations are present on the dorsal fin and on the posterior half of the ventral fin. The mouth is ventral and relatively small; its width is equal to about one-third of the greatest width of the body. The median part of the upper lip is bare; the rest of the lip is bordered by a single row of elongate papillae. Deep lateral folds are present in the lip. The beaks are slender and bear short, conical ser- rations. The upper beak is in the form of a broad arch with long, slender, terminally ex- panded lateral processes; the lower beak is very broadly V-shaped and slender. There are two upper and four lower rows of teeth. The upper rows are equal in length, and the second upper row is narrowly interrupted medially. The lower rows are complete; the first three rows are approximately equal in length but somewhat shorter than the upper rows, whereas the fourth lower row is notice- ably shorter (fig. 104). A developmental series of tadpoles was obtained from a clutch of eggs on Barro Colo- rado Island, Panama. The eggs hatched on June 8, 1963. The average length of the body of hatchlings is 2.7 mm., and the tail length is 5.0 mm. These tadpoles are in developmen- tal stage 20; the cornea is not visible, and the oral suckers are well developed. There is a large yolk sac and short, many-stalked gills. Tadpoles after five days were in developmen- tal stage 25 and had a functional spiracle and Fig. 103. Tadpole of Htjla rujitela, K.U. No. 104300. x 2. 244 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 104. Mouth of tadpole of Hyla rufitela, K.U. No. 104300. x 15. eyes; the gills and oral suckers were lost. The beaks are formed, and two upper and two lower rows of teeth are present in these tad- poles which have an average body length of 3.7 mm. and a total length of 9.7 mm. Dark- pigment is present on the dorsum and forms transverse bands on the dorsal surface of the caudal musculature. After 16 days, the tad- poles were still in developmental stage 25 but had developed the four lower rows of teeth. The average body length is 3.9 mm., and the total length is 11.1 mm. After 28 days the average length increased to 4.9 mm., and the total length to 12.7 mm. In these tadpoles, pigment is present anteriorly on the dorsal fin. At an age of 32 days, the tadpole is still in developmental stage 25 and has an average body length of 5.5 mm. and a total length of 15.3 mm. Definite flecks are present on the dorsal and ventral fins and the pigmentation extends ventrolaterally on the body. Mating Call: The call of Hyla rufitela consists of a series of clucks. Three different individuals produced call groups having nine, 11, and 21 notes per call group. The note repetition rate varies from 22 to 63 ( mean, 38 ) notes per minute. Seven to nine harmonics are evident in the notes (pi. 23, fig. 3). Each note has a duration of about 0.05 of a second. The fundamental frequency is at about 400 cycles per second; the dominant frequency usually is the third harmonic at about 1600 cycles per second. The second and fourth harmonics are also emphasized. In many of the notes there is a rise in pitch towards the end of the note. Fouquette (1961a, p. 599) noted that the notes in some individuals were followed by a guttural trill, which he suggested was prob- ably a "warm-up" call. Observations on calling males indicate that the normal note is pro- duced by a rapid expansion of the vocal sac; sometimes, this complete expansion is fol- lowed by a series of quick pulsations of the vocal sac. I do not believe that this is a "warm- up" call. Natural History: Hyla rufitela inhabits tropical rain forests; apparently the species is active throughout most of the year. Dunn (1931b, p. 414) reported this species calling on Barro Colorado Island in August. Noble (1918, p. 343) reported a gravid female from Maselina Creek on August 16. Charles W. Myers observed breeding activity at the Rio Cahuita, Veraguas Province, Panama, on Oc- tober 26, 1966, and on Cayo de Agua, Bocas del Toro Province, Panama, on November 2, 1964. I have found calling males on Barro Colorado Island and at Achiote, Colon Prov- ince, Panama, in June and on the Peninsula Valiente, Bocas del Toro Province, Panama, in March. Males usually call from dense vegetation and secluded places just above standing water in swamp forest. On Barro Colorado Island and at Achiote, the preferred calling sites were in thickets of the pita plant, Aechmea (= Ananas) magdalenae. The eggs are deposited as a surface film in shallow water. A clutch of eggs found on Barro Colorado Island on June 6, 1963, was about 15 cm. in diameter. The jelly is clear; the vegetal pole is pale cream and the animal pole is black. The diameter of the eggs is about 1.8 mm., and the diameter of the vitel- line membrane is about 2.1 mm. Tadpoles have been found in shallow, vegetation-choked ponds and muddy pools in swamp forests. Two juveniles were metamorphosed from tadpoles obtained at Golfito, Puntarenas Province, Costa Rica on June 18, 1961. The small frogs have snout-vent lengths of 19.7 and 21.5 mm. The dorsum is pale green; the eyelids are brown. There are scattered black flecks on the back. The limbs are yellowish green and the hands and feet are pale yellow. The throat is pale green, and the venter is silvery white. There is no red on the webs or the posterior surfaces of the thighs. Remarks: Cope (1886), Noble (1918), Dunn (1931b), and Taylor (1952c) referred Central American specimen:: of this species to 1970 DUELLMAN: HYLID FROGS 245 Hyla albomarginata Spix. Fouquette (1961a) demonstrated the specific distinctness of the Central American specimens from those in the Amazon Basin assignable to albomarginata. A considerable hiatus exists between the ranges of these species. Hyla nifitela is unknown from eastern Panama, and albomarginata occurs in the Amazon Basin, Guianas, and southeast- ern Brasil and questionably in the Maracaibo Basin in Venezuela. Etymology: The specific name is derived from the Latin rufus, meaning red, and the Latin tela, meaning web, and refers to the dis- tinctive red webbing. Distribution: Hyla nifitela occurs in rain forest and swamp forest on the Caribbean low- lands at elevations of less than 300 meters from east-central Nicaragua to central Panama and in the Golfo Dulce region of the Pacific low- lands of Costa Rica (fig. 105). See Appendix 1 for the locality records of the 94 specimens examined. The Hyla boans Group Definition: The frogs comprising this group are large species inhabiting lowland forests; in Central America, males attain snout- vent lengths of 131 mm., and females, 117 mm. The dorsum usually is tan or gray with darker irregular blotches and in many speci- mens a narrow, dark, vertebral line is present. Transverse bars are present on the limbs, and vertical dark lines or reticulations are present on the thighs and flanks in some species. The palpebral membrane is reticulate in one spe- cies (boans) and clear in the others. The hands are about one-third webbed in one spe- cies (crepitans) and at least three-fourths webbed in the other species; the feet are at least three-fourths webbed. A strong tarsal fold is present, but an axillary membrane is absent. A dermal appendage is present on the heel in some species (boans and pardalis). Males have a projecting prepollex and a me- Fig. 105. Distribution of Hyla nifitela. 246 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 dian subgular vocal sac. The skull is only moderately ossified, and an elongate fronto- parietal fontanelle is present (fig. 106). The nasals are slender, weakly ossified, widely sep- arated medially, and have weak maxillary pro- cesses. The sphenethmoid is broad and ex- tends anteriorly between the nasals; in the two largest species (boons and faber) the posteromedian part of the sphenethmoid is de- pressed and the anterolateral edges are ele- vated, so as to form distinct canthal ridges. The squamosal is in bony articulation with the crista parotica, and the anterior arm of the squamosal extends about half the distance to the maxillary. The prevomer is large and bears a long, angular, dentigerous process ( fig. 106 ) . The palatine is slender, and the pterygoid is well developed and bears a long medial ramus which articulates with the prootic. The tad- poles have robust bodies, moderately deep Fie. 106. Dorsal (A) and ventral (B) views of the skull of Hyla rosenbergi, K.U. No. 84991. X 3. caudal fins and small mouths with two upper and four lower rows of teeth. The mating calls consist of low, rather well-modulated short notes resembling the hammering of a stick on a hollow log. The haploid number of chromosomes is 12 (known only in crepitans). Composition: Seven species are currently recognized in this group; all occur in South America. Two species (boons and crepitans) are widespread in South America east of the Andes and range into Central America. Anoth- er Central American species extends south- ward on the Pacific slopes to northwestern Ecuador. The other species are strictly South American; langsdorffii, circundata, and faber are known only from Brasil, whereas pardalis extends from Venezuela and the Guianas to southeastern Brasil. Of the three Central American species, 279 preserved frogs, 12 skeletons, seven lots of tadpoles, and one pre- served clutch of eggs have been examined. Comments: Some authors, such as Taylor and Smith (1945, p. 596) have separated this group from Hyla. The earlier generic name available for the group is Boana Gray, 1825 (generotype, Ratio boons Linnaeus, 1758). Wagler (1830) designated Hyla palmata Daudin, 1803 (=Hyla boons) as the type spe- cies of Hypsiboas, the generic name used by Cope (L867a), who apparently was unaware of Gray's name. Cope (1887, pp. 13-14) in- clude in the genus Hyla miliaria Cope, Hyla xerophyllum Dumeril and Bibron (=Hyla crepitans Wied), Hyla albomarginata Spix, Hyla crepitans Wied (including Hyla pal- mata Daudin ) , Hyla crassa Brocchi, and Plec- trohyla guatemalensis (Brocchi). Cope ob- viously based his concept of Hypsiboas on the presence of a protruding prepollex and con- sequently placed together species that are now considered to be members of four groups of Hyla and of the genus Plectrohyla. Cochran (1955) placed crepitans in the same group as faber and pardalis, whereas Cochran and Goin ( 1970 ) separated crepitans from the "maxima" (=boans) group appar- ently solely on the basis of less webbing on the hand in the former. The similarities of other external features, the structure of the skull, the characters of the tadpoles, and the nature of the mating call strongly suggest close phylogenetic relationships. 1970 DUELLMAN: HYLID FROGS 247 Hyla boons, fabcr, and rosenbergi have dis- tinctive mating behavior in which the male builds a nest of mud or gravel. I am unaware of any such behavior in crepitans, so perhaps this apparent lack of specialized mating be- havior in crepitans is indicative of more distant relationships with the other species; on the other hand, possibly crepitans is the most primitive member of the group. Structurally, the adults of crepitans are more generalized than hoans, faber, and rosenbergi. Several evolutionary trends are evident in this group. Hyla crepitans has the least de- veloped prepollical spine, whereas the spines are large, pointed, and curved in boons, faber, pardalis, and rosenbergi (fig. 107). In the Central American species there is a positive correlation between size and the extent of the webbing on the hands and feet; the smallest species (crepitans) has less webbing than rosenbergi, which in turn has less than the larger boons (figs. 108 and 109). A similar correlation exists with certain parameters of the mating call, such as note repetition rate and duration of notes (table 27). The differentiation of the Hyla boans group undoubtedly occurred chiefly in South America east of the Andes. Hyla rosenbergi apparently resulted from the isolation of a Fig. 107. Palmar view of the right prepollical spine of Hyla boans, K.U. No. 104406. X 7. stock of boans-hke frogs either on the Pacific- lowlands of northwestern South America that later moved into Central America or in the Central American lowlands that later moved southward on to the Pacific lowlands of South America. Certainly, the three species in Cen- tral America represent three different inva- sions from South America. Hyla crepitans Wied Hyla crepitans Wied, 1824a, pi. 47, fig. 1 [type specimens unknown; type localities given as Tamboril, Jiboya, and Areal da Conquista, Bahia, Brasil]; 1824b, p. 671. Boulenger, 1882a, p. 352. Gunther, 1901 (1885-1902), p. 283. Hypsiboas crepitans: Wagler, 1830, p. 200. Hyla pugnax O. Schmidt, 1857, p. 11 [holotype, unknown, from "Chiriqui-Flusse unweit Bocca del toro," Panama ( O. Schmidt. 1858, p. 6); J. von Wars- zewicz collector]. Brocchi, 1882, p. 41. Hyla xeropliylla: Brocchi, 1882, p. 44. Diagnosis: This moderately large frog has a mottled dorsum, vertical dark lines on the flanks and posterior surfaces of the thighs, a long, low snout, and a protruding prepollex. It differs from other Central American species in the group by having less webbing; the web extends to the base of the disc of the fourth finger in boans and rosenbergi but only to the distal end of the antepenultimate phalanx in crepitans. Furthermore, crepitans can be dis- tinguished from boans by the absence of a calcar on the heel and the absence of reticula- tions on the palpebral membrane in boans. Hyla rufitela differs from crepitans by having a green dorsum, unmarked flanks and posterior surfaces of the thighs, red webbing, a weak tarsal fold and much more webbing on the hand. Members of the genus Plectrohyla and the Hyla miliaria group have protruding pre- TABLE 27 Comparison of Certain Parameters, With Means in Parentheses. of the Mating Calls of Species in the Hyla boans Group. Species N Notes per Call Group Duration of Notes (sec.) Fundamental Frequency (cps) Dominant Frequency (cps) H. crepitans _... 3 3-5 (4.0) 2-5 (2.8) 3-10 (6.0) 0.03-0.04 (0.037) 0.06-0.07 (0.062) 0.25-0.28 (0.26) 178-185 (182) 130-143 (136) 104-130 (114) 965-1288 H. rosenbergi H. boans 5 3 (1107) 260-286 (272) 832-910 (869) 248 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 pollices; the latter group differs from Hi/la crepitans by having more webbing and dermal fringes on the limbs. Frogs of the genus Plec- trohijla have more robust bodies and arms, short heads, and long fingers with small discs. Description: Males of this moderately large species attain a maximum snout-vent length of 58.5 mm., and females reach 67.9 mm. In a series of 19 males from central Panama, the snout-vent length is 50.0 to 58.5 (mean, 54.5) mm.; the ratio of tibia length to snout- vent length is 0.531 to 0.583 (mean, 0.556); the ratio of foot length to snout-vent length is 0.378 to 0.413 (mean, 0.397); the ratio of head length to snout-vent length is 0.327 to 0.359 (mean, 0.340); the ratio of head width to snout-vent length is 0.337 to 0.364 (mean, 0.351), and the ratio of the diameter of the tympanum to that of the eye is 0.704 to 0.846 (mean, 0.781). Five females from the same locality have snout-vent lengths of 62.8 to 67.9 (mean, 64.6) mm. They differ from the males in having a proportionately larger tympanum; the ratio of the diameter of the tympanum to that of the eye is 0.828 to 0.887 (mean, 0.848). The head is as wide as, or slightly wider than, the body; the top of the head is flat or faintly concave and the eyes are large and prominent. In the dorsal profile the labial border is round, whereas the snout is trun- cate; in lateral profile the snout is round. The snout is long, and the protuberant nostrils are situated at a point about five-sixths of the distance from the eyes to the tip of the snout. The canthus is slightly elevated and round; the loreal region is barely concave and slopes laterally to the thin, slightly flared lips. A thin dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold obscures the upper edge of the tym- panum, which otherwise is distinct and sepa- rated from the eye by a distance equal to about half of the diameter of the tympanum. The arms are moderately long and slender; an axillary membrane is absent. A distinct dermal fold is present on the ventrolateral edge of the forearm, and a weak transverse fold is present on the wrist. The fingers are moderately long and slender and bear rela- tively small discs; the width of the disc on the Fie. 108. Hand (A) and foot (B) of Hyla crepi- tans, K.U. No. 77020. X 4. 1970 DUELLMAN: HYLID FROGS 249 Fig. 109. Hands and feet of members of the Hijla boans group. A and C. Hyla rosenbergi, K.U. No. 96065. X 2.5. B and D. Hyla boans, K.U. No. 108848. X 1.5. 250 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 third finger is slightly greater than half of the diameter of the tympanum. The subarticular tubercles are large and conical; none is bifid. The supernumerary tubercles are low and subcorneal. No distinct palmar tubercle is evident. In males, the prepollex is greatly en- larged, protuberant, and recurved. In many individuals, the tip of the prepollical spine protrudes through the end of the prepollical eminence. The fingers are about one-third webbed (fig. 108A). The webbing is vestigial between the first and second fingers, and ex- tends from the base of the penultimate pha- lanx of the second finger to the base of the antepenultimate phalanx of the third, and from the middle of the antepenultimate pha- lanx of the third to the base or middle of the antepenultimate phalanx of the fourth finger. The legs are long and slender; the heels of the adpressed limbs overlap by about one-fifth of the length of the shank. The tibiotarsal articulation extends beyond the tip of the snout. A strong transverse dermal fold is present on the heel; the tarsal fold is weak to moderately developed and seldom extends the full length of the tarsus. The inner metatarsal tubercle is rounded, elliptical, and broadly visible from above. No outer metatarsal tu- bercle is evident. The toes are long and slen- der and bear discs that are nearly as large as those on the fingers. The subarticular tuber- cles are moderately large and conical, and the supernumerary tubercles are moderately large and subcorneal. The toes are about three-fourths webbed (fig. 108B). The web- bing extends from the middle of the penulti- mate phalanx of the first toe to the base of the penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the base of the penultimate pha- lanx of the third, from the distal end of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth and on to the distal end of the pen- ultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. There is no noticeable anal sheath, but vertical dermal folds are present on either side of the anal opening and numerous small tubercles are present below the opening. The skin on the throat, belly, and posteroventral surfaces of the thighs is strongly granular; elsewhere, the skin is smooth. The tongue is broadly cordi- form, noticeably notched posteriorly, and barely free behind. The dentigerous processes of the prevomers form sharply angled, nar- rowly separated, long elevations between the moderately large, round choanae. Males have 10 to 12 teeth on each process and a total of 20 to 24 (mean, 22.3) prevomerine teeth; fe- males have 12 to 14 teeth on each process and a total of 25 to 28 (mean, 26.4) prevomerine teeth. The vocal slits extend along the inner edge of the jaw from the midlateral base of the tongue to the angle of the jaw. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla crepitans is pinkish tan with irregular brown markings and usually a dark brown middorsal line (pi. 50, fig. 2). At night the dorsum varies from yel- lowish tan to pinkish tan with darker brown irregular markings on the back and narrow transverse bars on the dorsal surfaces of the limbs. A narrow, dark brown line commences on the snout and extends posteriorly to about the sacral region. The flanks are creamy tan with numerous dark brown vertical bars. The anterior and posterior surfaces of the thighs are pale pinkish tan; narrow brown vertical bars are present on the posterior surfaces. The anal area is dark brown, and the tubercles be- low the anal opening are tipped with white. The webbing is pinkish tan. The chin is white with brown flecks; the chest is white, and the abdomen is pale orange. The iris is silvery bronze or pale creamy yellow with a silvery cast; in some individuals there is a faint greenish tint on the dorsal part of the iris. The palpebral membrane is unmarked. By day, this frog becomes pale ashen gray; in some specimens there is no trace of dorsal markings, whereas in others the middorsal dark line is evident. In preservative, the dorsum is pale tan to pale reddish brown with darker brown spots and irregular markings on the back and nar- row transverse bands on the limbs. The verti- cal marks on the flanks and posterior surfaces of the thighs are dark brown or gray. The belly is creamy white. Tadpoles: No tadpoles are available from Central America; the following description is 1970 DUELLMAN: HYLID FROGS 251 based on K.U. No. 110600 from Villavicencio, Departamento de Meta, Colombia. A tadpole in developmental stage 39 has a body length of 18.0 mm. and a total length of 54.5 mm. In dorsal profile the body is ovoid; it is slightly wider than deep. The snout is rounded in dor- sal and lateral profiles. The eyes are moder- ately large, not widely separated, and directed dorsolaterally. The nostrils are directed an- terolaterally at a point about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed postero- dorsally at a point on the midline about two- thirds of the distance from the tip of the snout to the posterior end of the body. The caudal musculature is moderately heavy and tapers gradually to terminate just short of the pointed tip of the tail. The ventral fin is shal- low, whereas the dorsal fin is much deeper and reaches a high point at about the midlength of the tail; at this point the depth of the dorsal fin is slightly greater than the depth of the caudal musculature. The dorsal fin does not extend onto the body (fig. 110A). The dorsum and caudal musculature is pale yellowish tan; soft brown and gray suf- fusions are present on the dorsum of the body and caudal musculature and on the dorsal fin. In preservative, the bodv is pale erav with scattered black flecks. The venter is white. The caudal musculature is creamy tan with faint gray blotches; the caudal fins are trans- parent with faint grayish brown flecks. The mouth is anteroventral and small; its width is equal to about one-third of the great- est width of the body. The median part of the upper lip is bare; elsewhere, the lips are bor- dered by a single row of conical papillae. The lips are folded laterally. The beaks are rela- tively slender and bear fine serrations. The upper beak is transverse with posteriorly an- gled lateral processes that are slightly ex- panded distally. The lower beak is broadly V-shaped. There are two upper and four lower rows of teeth. The upper rows extend laterally to the margins of the lip and the second upper row is narrowly interrupted medially. The first and second lower rows are equal in length, but slightly shorter than the upper rows. The first lower row is nar- rowly interrupted medially. The third lower row is somewhat shorter than the first and second, and the fourth lower row is extremely short (fig. 111A). Mating Call: The call of Hijla crepitans consists of a quickly repeated series of short, poorly modulated notes. Although several re- cordings were obtained, most of these are not i. r~^~"-"'-'' •-'--«V. , >.-_\ _,378ViBa*---,'~ - i '■ ■ - *- ]:, V'* « K-J^* Fig. 110. Tadpoles of the Hyla boons group. A. Hyla crepitans, K.U. No. 110600. X 2. B. Hyla rosenbergi, A.M.N.H. No. 51791. x 4. C. Hyla boons, K.U. No. 116777. x 2.5. 252 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 111. Mouths of tadpoles of the Hijla boans group. A. Hyla crepitans, K.U. No. 110600. x 15. B. Hyla rosenbergi, A.M.N. H. No. 51791. x 20. C. Hyla boons, K.U. No. 116777. x 15. suitable for analysis, because of background noise from the call of Physalaemus pustiilosus and Leptodactyhts. Recordings of three indi- viduals are suitable for analysis. In these, the call rate varies from 12 to 24 (mean, 22) call groups per minute. There are three to five notes in each call group. The duration of each note varies from 0.03 to 0.04 of a second, and there are approximately 110 pulses per second. The fundamental frequency varies from 178 to 185 ( mean, 182 ) cycles per second and the dominant frequency varies from 965 to 1288 (mean, 1107) cycles per second (pi. 25, fig. 1). Natural History: Hyla crepitans inhabits subhumid environments in lower Central America; apparently, its activity is limited to the rainy season, when the frogs congregate in shallow, grassy rainpools for breeding pur- poses. No evidence of a basin-like nest was observed by me or by Fouquette ("1966" [1967 1 , p. 170) in Panama. On June 18, 1963, at Camp Chagres, Canal Zone, Panama, nu- merous calling males and three clasping pairs were found in shallow water in a flooded field. These observations agree with those of Steb- bins and Hendrickson (1959, p. 520), who stated: "Both at Villavieja and Villavicencio [Colombia] and vicinity we found this frog [Hyla crepitans] in grassy areas with scattered bushes but not in the interior of dense forest. Several were found at the edge of riparian growth. The animals were usually found in or near the water of quieter parts of the streams or temporary rainpools." The same authors (1959, p. 522) mentioned eggs of this species. "The female was later opened, and a total of 1,064 eggs, ready for laying, were removed from her oviducts. At Villavicencio on No- vember 19, 1950, two pairs in amplexus were found in the water at the edge of rainpools. Two days later, upon removing them from a container in which they had been kept alive, we found the females had deposited eggs. These were surrounded by two jelly layers, the outer one adherent, the eggs forming a loose cluster. In alcohol, the diameters of the ova are 1.3 to 1.5 mm. and, of the outer jelly layer, 3.5 to 4.4 mm." Dr. John Lynch ob- tained the tadpoles of this species from rain- pools in a grassy field at Villavicencio on July 5, 1967. Remarks: Hyla levaillantii, doumercii, and xerophilla Dumeril and Bibron (1841) and Hyla indris Cope (1867a) are usually placed in the synonymy of Hyla crepitans. Hyla xero- philla was named from Cayenne, whereas the other three species were named from Surinam. The variability displayed by Hyla crepitans in South America suggests the possibility that geographical races possibly are recognizable; perhaps, more than one species is involved. Consequently, because none of these names is based on Central American material, I have not included them in the synonymy. Cochran ( 1955) included Hypsiboas circumdatus Cope 1970 DUELLMAN: HYLID FROGS 253 (1867a) in the synonymy of Hyla crepitans. Werner C. A. Bokermann has informed me ( in litt. ) that this Brasilian frog as now recognized probably consists of a complex of several spe- cies. The status of Hyla pugnax Schmidt ( 1857) possibly is open to question. The type speci- men can not be located; on the basis of the type description, it is highly possible that pugnax is the same as crepitans, although the possibility exists that it might be Hyla rosen- bergi. However, on the basis of size (62 mm.) as given by Schmidt and on the reduced amount of webbing between the third and fourth fingers, it is most likely that this name is associated with the frog now known as Hyla crepitans. Lynch and Fugler (1965, p. 11) recorded Hyla crepitans from "Laguna Yogoa," De- partamento de Cortez, Honduras. This record was based on a single male, A.M.N.H. No. 45997 ( in the Pratt collection from Honduras ) . According to the catalogues in the American Museum of Natural History, the specimen came from Tela, not Lago Yojoa. This speci- men is the only individual of Hyla crepitans known from north of Panama. I would be highly skeptical of the record if it were not for the presence in the same area of Cnemi- dophorus lemniscatus, another species un- known in Central America between central Panama and northern Honduras [see Echter- nacht (1968) |. Etymology: The specific name is Latin, meaning rattling, and evidently refers to the rattle-like call of this species. Distribution: Hyla crepitans occurs in subhumid environments on the Pacific low- lands of central Panama and the Caribbean lowlands of northern Honduras (fig. 112); the species is widely distributed in South America east of the Andes. See Appendix 1 for the locality records of the 77 specimens examined. Hyla rosenbergi Boulenger Hyla rosenbergi Boulenger, 1898a, p. 123 [syn- types, B.M.N.H. Nos. 1947.2.12.71-75 from Cachabe, Esmeraldas Province, Ecuador; W. F. H. Rosenberg collector]. Taylor, 1954b, p. 626. Diagnosis: This large frog has a mottled 82° 80° 78° 10° 10° i i • H. crepitans ° H. boons "" —"^— ^~^« //%"~^ o J- •••* ON. \ • ~7 ;o \ N 8° \i) \ \ ° f 8° 0 IOC ••/ — ^ i \ o ■-' s. / KILOMETERS i 82° 80° 78° Fig. 112. Distribution of Hyla crepitans and Hyla boons. A record for H. crepitans from Tela, Honduras, is not shown. 254 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 dorsum, vertical dark lines on the flanks and posterior surfaces of the thighs, a long, low snout, and a protruding prepollex. It differs from Hyla crepitans by having more webbing; the web extends to the base of the disc on the fourth finger in rosenbergi but only to the distal end of the antepenultimate phalanx in crepitans. Furthermore, rosenbergi is a much larger species (males to 90 mm., as compared to 58 mm. in crepitans). Hyla rosenbergi dif- fers from boons by lacking a calcar on the heel and reticulations on the palpebral mem- brane and by having pale, instead of dark, webbing. The smaller Hyla rufitela can be distinguished by having less webbing (red in life), a green dorsum, and unmarked flanks and thighs. Frogs of the Hyla miliaria group and Plectrohyla also have projecting prepol- lices. Frogs in the former group have fully webbed hands and feet and dermal fringes on the limbs. Frogs in the genus Plectrohyla have robust bodies and arms, short snouts, and long fingers with small discs and little web- bing. Description: Males of this large species attain a maximum snout-vent length of 90.0 mm., and females reach 93.2 mm. In a series of 18 males from the Rio Tuira at the Rio Mono, Darien Province, Panama, the snout- vent length is 78.0 to 85.3 (mean, 82.1) mm.; the ratio of tibia length to snout-vent length is 0.535 to 0.593 (mean, 0.565); the ratio of foot length to snout-vent length is 0.407 to 0.435 ( mean, 0.424 ) ; the ratio of head length to snout- vent length is 0.319 to 0.349 (mean, 0.333); the ratio of head width to snout-vent length is 0.312 to 0.327 (mean, 0.321), and the ratio of the diameter of the tympanum to that of the eye is 0.797 to 0.972 (mean, 0.878). Seven females from the same locality have snout-vent lengths of 82.6 to 90.8 mm. and do not differ significantly in proportions from the males. Panamanian specimens agree with those from the vicinity of the type locality in Esmeraldas Province, Ecuador; 24 males from Esmeraldas have snout-vent lengths of 77.7 to 90.8 (mean, 83.6) mm. Specimens from the western part of the range in Puntarenas Province, Costa Rica, are noticeably smaller; 15 males have snout-vent lengths of 63.0 to 75.7 (mean, 67.9) mm. The head is nearly as wide as the body, and the top of the head is slightly concave. In dorsal profile, the snout is acutely rounded; and in lateral profile, it is bluntly rounded. The snout is long; the protuberant nostrils are situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is slightly elevated and rounded; the loreal region is inclined ventrolaterally, and the lips are thin and barely flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance equal to less than half of the diameter of the tympanum. The upper arms are slender, whereas the forearms are moderately robust. An axillary membrane is absent. A distinct glandular ridge extends from the elbow on to the base of the fourth finger, and a weak transverse dermal fold is present on the wrist. The fingers are moderately short and robust and bear large discs; the width of the disc on the third finger is equal to about three-fourths of the diameter of the tympanum. The subarticu- lar tubercles are large and flattened; none is bifid. The supernumerary tubercles are small, subcorneal, and indistinct. A low, flat, par- tially bifid palmar tubercle is present. In males, the prepollex is greatly enlarged and projecting; in some individuals, the prepollical spine protrudes through the skin of the pre- pollex. The fingers are about three-fourths webbed (fig. 109A). The webbing extends from the distal end of the antepenultimate phalanx of the first finger to the base of the penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the distal end of the antepenulti- mate phalanx of the third, and from the middle of the penultimate phalanx of the third to the distal end of the penultimate phalanx of the fourth finger. The hind limbs are moderately long, but not especially slender; the heels of the adpressed limbs overlap by about one- third of the length of the shank. The tibio- tarsal articulation extends to a point between the eye and the nostril. A transverse dermal fold is present on the heel, and several small tubercles are evident on the heel. A distinct, curved, inner tarsal fold extends the full 1970 DUELLMAN: HYLID FROGS 255 length of the tarsus, and a distinct, straight outer tarsal fold also is present. The inner metatarsal tubercle is low, flat, elliptical, and barely visible from above. In some individuals, a faint outer metatarsal tubercle is evident. The toes are moderately long and slender and bear discs that are somewhat smaller than those on the fingers. The subarticular tuber- cles are moderately large and subcorneal; the supernumerary tubercles are small, conical, and present only on the proximal segments of each digit. The toes are about four-fifths webbed (fig. 109C). The webbing extends from the base of the disc of the first toe to the base of the disc of the second and on to the base of the penultimate phalanx of the third, from the base of the disc of the third to the base of the penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs and is covered by a short anal sheath. Numerous small tu- bercles and a pair of vertical dermal folds are present below the anal opening. The skin on the throat, belly, and posteroventral sur- faces of the thighs is granular; elsewhere, the skin is smooth, except that in many individuals, minute tubercles are present on the dorsum, especially on the head. The tongue is elon- gately ovoid, emarginate, or very shallowly notched posteriorly and not free behind. The dentigerous processes of the prevomers are strongly angled, narrowly separated eleva- tions between the large, quadrangular cho- anae. Males have 14 to 17 teeth on each process and a total of 29 to 33 (mean, 31.0) prevomerine teeth, whereas females have 16 to 18 teeth on each process, and a total of 32 to 35 (mean, 33.8) prevomerine teeth. The vocal slits extend along the inner edge of the jaw from the anterolateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and only mod- erately distensible. The general coloration of Hyla rosenbci^i consists of a yellowish tan dorsum with or without faint mottling and usually with a distinct dark brown middorsal line (pi. 50, fig. 4). The dorsum varies from pale yellow- ish tan to reddish tan or olive-gray, usually with faint, irregular darker blotches. Most individuals have a dark brown or black mid- dorsal line beginning on the snout and extend- ing to the scapular or even to the sacral region. The flanks and posterior surfaces of the thighs are pale yellowish brown with creamy gray vertical bars, which usually are wider than the paler interspaces. The anterior surfaces of the thighs and the webbing varies from yellowish tan to pale orange-brown. The throat is yellowish gray, and the belly is pale bluish green. The blue is most intense in the axilla and proximally on the ventral surfaces of the thighs. The iris is pale golden above and silvery white below. In preservative, the dorsum varies from reddish brown to pale creamy tan; indistinct and irregular darker transverse bars are evi- dent on the dorsal surfaces of the limbs in some individuals. The markings on the pos- terior surfaces of the thighs usually are evi- dent; in some individuals these markings con- sist of rather narrow, vertical dark lines, whereas in others, the interspaces are much narrower than the broad vertical dark marks. The markings on the flanks basically consist of a series of vertical dark lines, but in many individuals these are interconnected, so as to form a network. In most breeding males, the throat is dark gray or grayish brown, with or without creamy white flecks; however, the throat in some males is creamy white with a faint suffusion of gray. Tadpoles; I have not obtained the tad- poles of this species in Central America; the following description is based on A.M.N.H. No. 51791 from Camp Creek, below Yavisa, Darien Province, Panama (Breder, 1946, p. 409). A tadpole in developmental stage 27 has a body length of 9.2 mm. and a total length of 27.0 mm. The body is ovoid in dor- sal profile and has a rounded snout; in lateral profile, the snout is acutely rounded; the eyes are moderately large, broadly separated and directed dorsolaterally. The nostrils are di- rected anterolaterally at a point about mid- way between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posterodorsally at a point on the midline slightly posterior to the midlength of the body. The anal tube is moderately short and dextral. The caudal musculature is moderately robust and tapers gradually to a slender point at the 256 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 tip of the pointed tail. The ventral fin is shal- low anteriorly and somewhat deeper posterior- ly, whereas the dorsal fin is much deeper than the ventral one and does not extend on to the body (fig. HOB). In preservative, the dorsum of the body is dark brown, and the venter is creamy tan. The caudal musculature is pale brown; dark brown flecks and blotches are present on the caudal musculature and fins. The pigment tends to form transverse bars on the dorsal surface of the musculature. The mouth is anteroventral and small; the width of the mouth is equal to about one- third of the greatest width of the body. The mouth is completely bordered by papillae; medially on the upper lip there is only one row, but for the most part two rows are pres- ent on the rest of the lips, which are deeply folded laterally. The beaks are moderately slender and bear pointed serrations. The up- per beak is broad and has long slender lateral processes. The lower beak is broadly V- shaped. There are two upper and four lower rows of teeth. The upper rows are long and extend to the margins of the lips; the second upper row is narrowly interrupted medially. The first lower row is interrupted medially in some specimens. The first three lower rows are nearly as long as the upper ones, whereas the fourth lower row is noticeably shorter and fragmented in some individuals (fig. 11 IB). Breder (1946, pp. 414-415) illustrated the development of Hyla wsenbergi based on the tadpoles that I have examined. His otherwise excellent series of illustrations is marred by an error of not showing the fourth lower tooth row in the mouth of Hyla wsenbergi. Mating Call: The call of Hyla wsen- bergi consists of a short series of low-pitched short notes, "tonk-tonk-tonk." The call is loud and carries for great distances. Recordings obtained in Costa Rica were compared with those from eastern Panama and found not to differ significantly. Call groups consist of two to five (mean, 2.8) notes. Call groups are re- peated at a rate of 32 to 58 (mean, 43) groups per minute. Each note has a duration of 0.05 to 0.07 (mean, 0.06) of a second. The funda- mental frequency varies from 130 to 143 (mean, 136) cycles per second. The second harmonic is the dominant frequency at 260 to 286 (mean, 272) cycles per second (pi. 25, fig. 3). Natural History: Hyla wsenbergi is a forest inhabitant. The breeding season seems to be rather long in this species. Calling males have been heard from April through August in southeastern Costa Rica. Although I have never observed mating in this species, I have encountered numerous calling males. At Tacarcuna and the Rio Mono in Darien Province, Panama, males were calling from trees over swamps. At the latter locality, and at several sites in Punta- renas Province, Costa Rica, I have observed the males calling from shallow water in swamp forest or in marshes. However, I have not observed clasping pairs or the deposition of eggs. My own observations seem to be in contradiction with the detailed report on the life history of this species by Breder ( 1946, pp. 409-416, pis. 48-53). However, I reiterate that I have not observed actual mating; prob- ably my observations are indicative only of the calling behavior early in the breeding season. Breder presented a detailed account of the mating behavior in Hyla wsenbergi; his ob- servations were made at Camp Creek, below Yavisa, Darien Province, Panama, in March 1924. He stated: "Breeding is accomplished in the heavy forest along the banks of drying stream beds. Here the male makes a circular depression, typically in the soft earth at the edges of the remaining pools. These fill with water, usually by seepage, and here the males sit and call . . . although during the nest constructing, frogs are very timid, in strong contrast to their later behavior, the normal nests are evidently made by the males' pivot- ing around on their hind end and patting the walls with their front feet." Breder gave measurements for 16 nests, which had diame- ters of 20 to 33 (mean, 27.0) cm. and depths of 13 to 82 (mean, 51) mm. Breder com- mented that after the nest was constructed, the males called repeatedly for several nights until females were induced to mate with them. Breder ( 1946, p. 413) noted that the males remained in the nests and the females come to the nests, apparently attracted by the call- ing of the male. Breder illustrated by a series 1970 DUELLMAN: HYLID FROGS 257 of photographs a sequence in which the male left the nest. He stated: "It was the only time in which a male was noted to leave his nest and pursue a female that evidently was not about to enter. It is evident that the fe- male entered the back of the nest, that is, at the side to which the male had his back. Other observations indicate that this is the usual order of procedure. It allows the female to jump on the back of the male, which may not be necessary but is usually done. The male at once turns and reverses the position as shown in the final photograph in that series. As earlier noted, the placing of another male near the nest caused the owner to face the other way. It is possible, although it could not be determined in the field, that actually the male is presenting his back to a possible female visitor as part of the courtship pro- cedure." Goeldi (1895, p. 89) first reported the building of such kinds of nests in Hyla faber; as pointed out by Lutz ( 1960, p. 61 ) Goeldi erroneously thought that the females built the nests. However, in Hyla faber, like in rosenbergi, the males do the construction. Lutz also presented observations on aggres- sive behavior between males of Hyla faber and pointed out that the fighting males utilize the long curved prepollical spines. Breder's tadpoles were obtained in March. In the same month, he also obtained several metamorphosing young. Five completely metamorphosed young have snout-vent lengths of 13.8 to 15.5 (mean, 14.8) mm. The small frogs have faint transverse bands on the limbs and practically no webbing between the fin- gers. Remarks: On June 1, 1962, Richard E. Zweifel collected a single specimen of a rosen- bergiAike Hyla (A.M.N.H. No. 69766) from the Rio Bejueo, near Bejueo, Panama Province, Panama. This specimen, an adult male having a snout-vent length of 78.2 mm. lacks a mid- dorsal dark stripe and has reduced webbing between the fingers; in the latter character it is much like Hyla crepitans. Zweifel collected this specimen as a voucher for an uncollect- ed tape-recorded specimen. The recording (A.M.N.H. Tape No. 122-2; pi. 25, fig. 2) of the other individual, one of several not col- lected, is difficult to place; in certain aspects it is like crepitans and in others like rosen- bergi. The call is a continuous series of notes; the repetition rate is 130 notes per minute. Each note has a duration of 0.08 of a second. The fundamental frequency is 135 cycles per second, and two harmonics (405 and 1215 cycles per second) are emphasized. Perhaps, at this locality, there is a population of hybrids between Hyla crepitans and Hyla rosenbergi. Noble (1924, p. 66) first recorded Hyla rosenbergi from Central America. Apparently the first Panamanian specimen was collected on the Rio Bayano on March 22, 1911, by Meek and Hildebrand. The second individual (U.S.N.M. No. 50209) supposedly was ob- tained on June 6, 1912, by E. A. Goldman at Cana, Darien Province, Panama ( Schmidt, 1933a, p. 6). The record from Cana is ques- tionable; Hyla rosenbergi occurs only at low elevations, and Cana lies at an elevation of 500 meters. Perhaps, the specimen came from the Tuira Valley adjacent to the Serrania de Pirre where Cana is located, or maybe this is the specimen that Noble (1924, p. 6) reported from Arrijam ( =Arraijan). Netting (1935, p. 15) reported the species from the Canal Zone and noted that the two specimens from there did not agree perfectly with the description and figure of an Ecuadorian specimen given by Boulenger (1898a, p. 123). A comparison of the series of specimens now available from Costa Rica and Panama with a recently ob- tained series of 28 specimens from Esmeraldas Province, Ecuador, shows no noticeable differ- ences, except that specimens from the southern part of the range are somewhat larger than those from the northern part. Hyla rosenbergi seems to occupy an eco- logical position intermediate between Hyla crepitans and boans. The latter seemingly is restricted to more humid forest, whereas the former is an inhabitant of drier forest. In the northeastern part of the range, in Puntarenas Province, Costa Rica, Hyla rosenbergi seems to be restricted ecologically by the dry forest, because in that part of the range the species only inhabits the humid forest of the Golfo Dulce region. Etymology: The specific name is a patro- nym for Mr. W. F. H. Rosenberg, the collector of the type specimen. Distribution: Hyla rosenbergi is known 258 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fie. 113. Distribution of Hyla rosenbergi. from the Pacific lowlands of lower Central America and northwestern South America; it ranges from extreme southeastern Costa Rica, through Panama and Colombia to northwest- ern Ecuador (fig. 113). See Appendix 1 for the locality records of the 190 specimens examined. Hyla boans (Linnaeus) Rana boans Linnaeus, 1758, p. 213 [no type desig- nated; from "America"; Andersson ( 1900, p. 17) noted a type specimen without a number in the Royal Muse- um of Sweden]. Rana maxima Laurenti, 1768, p. 32 [based on Seba ( 1734, pi. 72, fig. 3); no locality designated). Hyla boans: Daudin, 1803, p. 64. Andersson, 1900, p. 17. Calamita maxima: Schneider, 1799, p. 163. Hyla maxima: Gunther, 1859, p. 99. Diagnosis: This large species has a mot- tled dorsum, dark posterior surfaces of the thighs, a long, low snout, and a protruding prepollex. It differs from other Central Ameri- can species in the group by having a calcar on the heel, nearly fully webbed hands and feet, a reticulated palpebral membrane, and dark webbing. Hyla rosenbergi and crepitans have vertical dark lines on the posterior sur- faces of the thighs and pale webbing; both species lack a calcar and reticulations on the palpebral membrane. Hyla rufitela also lacks a calcar and reticulations on the palpebral membrane; furthermore, this smaller species has less webbing (red in life) and a green dorsum. The members of the Hyla miliaria group and Plcctrohyla also have projecting prepollices; the former group differs from Hyla boans by having dermal fringes on the limbs, and frogs in the genus Plectrohyla have more robust bodies, shorter heads, more ro- bust arms, and proportionately longer fingers with much smaller discs and less webbing. Description: This is the largest hylid frog in Middle America; males attain a snout-vent length of 132 mm., and females are known to reach 117.5 mm. In a series of 10 males from Camp Sasardi, San Bias, Panama, the snout- vent length is 100.7 to 131.9 (mean, 119.9) mm.; the ratio of tibia length to snout-vent length is 0.493 to 0.555 (mean, 0.517); the ratio of foot length to snout-vent length is 0.424 to 0.457 (mean, 0.436); the ratio of head length to snout-vent length is 0.337 to 0.362 (mean, 0.347); the ratio of head width to snout-vent length is 0.340 to 0.369 (mean, 0.352), and the ratio of the diameter of the tympanum to that of the eye is 0.569 to 0.649 (mean, 0.614). Two adult females from the same locality have snout-vent lengths of 116.3 1970 DUELLMAN: HYLID FROGS 259 and 117.5 mm.; they do not differ significantly from the males in proportions. The head is nearly as wide as the body, and the top of the head is noticeably concave. The eyes are moderately prominent and wide- ly separated. In dorsal profile the snout is acutely rounded; in lateral profile it is round. The snout is extremely long, nearly twice as long as the orbit. The nostrils are noticeably protuberant at a point about five-sixths of the distance from the eyes to the tip of the snout. The canthus is elevated and rounded; the loreal region is barely concave and slopes outward to the thin, barely flared lips. A thin dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point just posterior to the angles of the jaws. The fold obscures the upper edge of the tym- panum, which otherwise is distinct, separated from the eye by a distance slightly less than the diameter of the tympanum, and directed dorsolaterally. The arms are moderately long and robust; an axillary membrane is absent. A low tu- bercular fold is present on the ventrolateral edge of the forearm, and a weak transverse dermal fold is present on the wrist. The fin- gers are moderately short and robust and bear large discs; the width of the disc on the third finger is half again the diameter of the tym- panum. The subartieular tubercles are large and subcorneal; none is bifid. The supernu- merary tubercles are indistinct or absent. No distinctive palmar tubercle is evident. In males, the prepollex is greatly enlarged and projecting; in some individuals, the tip of the prepollical spine protrudes through the end of the prepollical process. The fingers are about three-fourths webbed ( fig. 109B ) . The web- bing extends from the distal end of the ante- penultimate phalanx of the first finger to the distal end of the antepenultimate phalanx of the second; from the base of the disc of the second to the base of the penultimate phalanx of the third, and from the base of the disc of the third to the base of the disc of the fourth finger. The hind limbs are moderately long and robust. The heels of the adpressed limbs barely overlap. The tibiotarsal articulation extends to the tip of the snout. A transverse dermal fold and a small triangular dermal flap, or calcar, are present on the heel. An elevated, curved, inner tarsal fold is present. A weak, straight, outer tarsal fold is evident in some individuals. The inner metatarsal tu- bercle is large, flattened, and elliptical. No outer metatarsal tubercle is present. The toes are long and slender and bear discs that are noticeably smaller than those on the fingers. The subartieular tubercles are moderately large and subcorneal; supernumerary tubercles are absent. The toes are fully webbed (fig. 109D). The anal opening is directed posteriorly at the upper level of the thighs. The opening is bordered below by numerous small tubercles. The skin on the throat, belly, and ventral sur- faces of the thighs is granular; elsewhere, the skin is smooth. The tongue is elongately ovoid, usually widest posteriorly, not free behind and usually emarginate. The dentigerous processes of the prevomers are narrowly separated or in contact medially. The processes are strongly angular ( transverse anteromedially and in- clined posterolaterally ) . The posterolateral projections of the processes form the postero- median border of the large, quadrangular cho- anae. Males have 19 to 29 teeth on each process and a total of 39 to 53 ( mean, 48.3 ) prevomerine teeth. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and only moderately dis- tensible. The general coloration of Hyla hoans con- sists of a grayish brown or an orange-brown dorsum with darker brown irregular mottling on the body and transverse bands on the lips (pi. 51, fig. 1). Some individuals are pale reddish tan or orange-brown (pi. 51, fig. 2). The throat is dark gray, the chest, belly, and ventral surfaces of the thighs are yellowish white. There is a slight bluish tint to the digital pads and to the undersides of the limbs and throat. The flanks are mottled with dark brown. The posterior surfaces of the thighs are dark brown or dark gray. The palpebral membrane is reticulated with silver. In preservative, the dorsum is dull brown or dull gray with darker brown blotches and reticulations on the back, and transverse bands on the limbs; in some individuals the dorsum is pale pinkish tan with faintly darker mark- ings on the body and dorsal surfaces of the 260 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 limbs. In some individuals a narrow brown niiddorsal stripe begins on the snout and ex- tends posteriorly on the body. The posterior surface of the thighs are dull brown or gray, usually without any evident pattern, but in some of the paler colored specimens, the trans- verse bands on the dorsal surfaces are con- tinuous onto the posterior surfaces of the thighs. The webbing on the hands and feet is dark brown, dark gray, or black. The throat is gray in all males. Recently metamorphosed young are pale brown above with black dots; the palpebral reticulation is absent. Two individuals hav- ing snout-vent lengths of 32.0 mm. show an intermediate phase of coloration. The dorsal surfaces of the body and limbs are pale orange-brown with darker brown bands on the limbs. The body is punctated with black. The posterior surfaces of the thighs are gray, and the flanks are reticulated with white and dark gray (pi. 50, fig. 3). The iris is pale brown with an orange-brown horizontal streak through the pupil, and the palpebral mem- brane is reticulated with pale yellowish brown. Tadpoles: Tadpoles of this species are available from Camp Sasardi, San Bias, Pana- ma, and from Santa Cecilia, Napo Province, Ecuador; a typical tadpole in developmental stage 36 from the former locality has a body length of 14.5 mm. and a total length of 40.0 mm. The body is ovoid, widest posteriorly, and noticeably wider than deep. In dorsal profile the snout is bluntly rounded, and in lateral profile it is acutely rounded. The eyes are moderately small, not widely separated, and directed dorsolaterally. The nostrils are directed anterolaterally at a point about mid- way between the eyes and the tip of the snout. The opening of the sinistral spiracle is di- rected posterodorsally at a point just below the midline about two-thirds of the distance from the snout to the posterior end of the body. The anal tube is short and dextral. The caudal musculature is moderately slender and tapers to a point just proximal to the tip of the pointed fin. The ventral fin is shallow throughout its length, whereas the dorsal fin, which does not extend onto the body, is deep- est at about midlength of the tail, at which point it is noticeably deeper than the caudal musculature (fig. 110C). The body is pale brown with dark green mottling. In preservative, the dorsum of the body is mottled dark brown and creamy tan; the venter is pale bluish white. The caudal musculature is pale creamy tan with dark brown blotches and reticulations; the latter extend onto the fins. The blotches tend to form transverse bands across the dorsal part of the caudal musculature. The mouth is anteroventral and moderately small; its width is equal to not more than half of the greatest width of the body. The median part of the upper lip is bare; the rest of the lips are bordered by a single row of moder- ately large, subcorneal papillae. Deep lateral folds are present in the lips. The beaks are moderately well developed and bear short serrations. The upper beak is broad and near- ly uniform in depth; long slender, terminally expanded, lateral processes are present. The lower beak is broadly V-shaped. There are two upper and four lower rows of teeth. The upper rows are long, and the second upper row is narrowly interrupted medially. The first three lower rows are equal in length, but shorter than the upper ones. The fourth lower row is noticeably shorter (fig. 111C). Hatchling tadpoles have a total length of about 4.5 mm. Large, filamentous gills and prominent oral suckers are present; the yolk sac is still large. The cornea is not transparent upon hatching. The hatchlings are dark brown or black in color. Mating Call: The call of Hyla Loans con- sists of a series of short, low-pitched notes. Usually each call group consists of three to 10 notes, although one individual produced 41 consecutive notes. The note repetition rate varies in three recordings from Camp Sasardi, Panama, from 44 to 82 (mean, 69) notes per minute. The notes have a duration of 0.25 to 0.28 (mean, 0.26) of a second and a pulse rate of 100 to 120 (mean, 107) pulses per second. The fundamental frequency varies from 104 to 130 (mean, 114) cycles per second, and the dominant frequency varies from 832 to 910 ( mean, 869 ) cycles per second ( pi. 20, fig. 3 ) . Natural History: Hyla boons inhabits humid tropical forest. Observations of this species in Central America are extremely lim- ited. Two juveniles were obtained from a bush and a tree in Darien Province in July, 1970 DUELLMAN: HYLID FROGS 261 1965. Charles W. Myers obtained some inter- esting data on the calling and breeding be- havior of the species at Camp Sasardi, San Bias Province, Panama, in January and Feb- ruary, 1967. Between January 11 and 13, he observed 10 males calling from trees along a river. Some of the individuals were at least 7 meters above the ground. On February 4, he found a male and a gravid female perched side by side on the limb of a tree, and on Feb- ruary 8, he found a male and female side by side in a freshly constructed nest. The following description of the nest is taken from the field notes of Charles W. Myers for February 8, 1967: "Since there are con- siderable differences in the sizes of tads in some nests and because I noticed some tads in a nest where eggs had just been laid, the same nest seems sometimes to be used more than once. The nests are circular and made at the edge of a sand or gravel bar or on tiny flats that result from deposition of sediment in the creek mouths . . . because the water level may vary from day to day, depth mea- surements were taken only from two fresh nests (i.e., containing eggs), both in sand and fine gravel. A basin 31 cm. in diameter was 6 cm. deep (bottom to water surface) in the center, and one 40 cm. in diameter was 7 cm. deep. One nest contained 2,722 eggs, but I saw another nest containing what seemed to be twice this number of hatchlings." Myers observed that two nests were built from coarse gravel, five nests from sand, and 15 nests in sand and fine gravel (pi. 9). The diameters of the 22 nests vary from 28 to 51 (mean, 36.5) cm. The breeding season may be rather ex- tended in this species, because in early Feb- ruary, Myers found at Sasardi gravid females, nests containing eggs, tadpoles in all stages of development, and recently metamorphosed young. Two recently metamorphosed young have snout-vent lengths of 16.6 and 17.5 mm. Remarks: For many years, this large tree frog was known by the name Hyla maxima ( Laurenti, 1768 ) . The earlier name for this species, Hyla boans (Linnaeus, 1758) had been overlooked until 1900 when the name was resurrected by Andersson (1900, p. 17). Although boans Linnaeus, 1758, has priority over maxima Laurenti, 1768, the name max- ima was used widely for many vears between 1850 and 1950. Goin and Layne ( 1958, p. Ill ) argued that on the basis of the Copenhagen Decisions (Hemming, 1953, p. 25) it would be better to retain the name maxima for the frogs known so long under that name than to use the name boans Linnaeus, 1758, a nomen oblitum, pending the precise wording in the revised Code. Although the Code of Zoologi- cal Nomenclature (Stoll, 1961, Art. 23, b) provides for a nomen oblitum ruling in cases such as that involving boans and maxima, the rule has been indefinitely suspended. There- fore, it seems only reasonable to proceed un- der a strict adherence to the law of priority and utilize the name boans for this large and widespread species of frogs. Several names apply to South American populations of this frog which apparently are synonyms of Hyla boans. However, due to some amount of uncertainty regarding the application of these names, and because none is based on Central American material, I have not included them in the synonymy. Most authors consider Hyla zebra (Shaw, 1802) and Hyla palmata Daudin, 1803, to be syno- nyms of Hyla boans. According to Cochran and Goin (1970), Hyla lactea Lonnberg, Hyla icavrini Parker, and Hyla miranda-ribeiri Me- lin are synonyms of Hyla boans. Etymology: The specific name boans is derived from the Greek Boanerges, the sons of Thunder; the name apparently refers to the voice of the frog. Distribution : Hyla boans is widespread in tropical lowland forests in South America east of the Andes; the species also occurs in the Atrato Valley in northwestern Colombia and in eastern Panama (fig. 112). See Appendix 1 for the locality records of the 32 specimens examined. The Hyla pseudopuma Group Definition: Members of this group are medium-sized pond-breeding species; males attain a maximum snout-vent length of 42.9 mm. and females, 47.6 mm. The dorsum is usually dull brown, marked by blotches, dor- solateral white stripes, or not. Transverse bands or dark flecks are present on the limbs. The iris is deep bronze, and the palpebral membrane is clear. The hands are no more 262 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 than one-third, and the feet two-thirds webbed. A distinct tarsal fold is present, but an axillary membrane and dermal folds or appendages on the limbs are absent. Males have a single, median, subgular or weakly bilobed vocal sac and horny nuptial excres- cences on the prepollices. The skull is well ossified, and a moderately small frontoparietal fontanelle is present (fig. 114). The sphen- ethmoid is broad and extends anteriorly be- tween the rather slender nasals, which are separated medially and broadly sutured to the sphenethmoid and have well-developed max- illary processes. The squamosal is in bony contact with the crista parotica, and the an- terior arm of the squamosal extends about one-half of the distance to the maxillary. The quadratojugal is present and articulates with the maxillary. The prevomer is well ossified and bears teeth, and the medial ramus of the pterygoid is in bony contact with the prootic. The tadpoles have rather robust bodies, mod- erately deep fins, and anteroventral mouths with two upper and three lower rows of teeth. The mating calls consist of a series of moder- ately short, poorly modulated notes. The hap- Fig. 114. Dorsal (A) and lateral (B) views of the skull of Hijla pseudopuma, K.U. No. 104347. X 5. loid number of chromosomes is 12 ( known only in pseudopuma). Composition: Two species (Hyla angus- tilineata and pseudopuma), the latter with two subspecies, comprise this group, which is endemic to the highlands of Costa Rica and western Panama. I have examined 489 pre- served frogs, 24 skeletons, 40 lots of tadpoles, and one preserved clutch of eggs of the three taxa. Comments: The members of the Hyla pseudopuma group are unique in lower Cen- tral America by being upland pond-breeders. This breeding behavior, coupled with the similarities in cranial and larval structure are the basis for placing the species in a single group. The coloration of the two species is noticeably different. Possibly the species differentiated from one another in two partially separated high- land areas — angustdineata in the Cordillera Central north of the Mesa Central in Costa Rica and pseudopuma in the Cordillera Tala- manca southeast of the Mesa Central. If such were the case, pseudopuma subsequently in- vaded the Cordillera Central, where it now occurs sympatrically with angustdineata. The members of this group are generalized in their cranial structure, tadpoles, external characters, and mating behavior. Possibly, they represent virtually unmodified descen- dants from an early generalized hylid stock in lower Central America. Hyla pseudopuma Giinther Hyla pseudopuma Giinther, 1901 (1885-1902), p. 274. Diagnosis: This moderate-sized brown Hyla with the fingers about one-third webbed is characterized by numerous pigmented su- pernumerary tubercles on the toes and yellow spots on dark brown or blue flanks. It differs from Smilisca puma by having a more acumi- nate snout and more webbing between the fingers. Smdisca sordida superficially resem- bles Hyla pseudopuma but has more webbing and many distinct pale blue or cream flecks on the posterior surfaces of the thighs, which are red, tan, or dark brown, unmarked, or with a few diffuse cream spots in pseudopuma. Content: Two subspecies are recognized: Hyla p. pseudopuma in the highlands of Costa 1970 DUELLMAN: HYLID FROGS 263 TABLE 28 Comparison of Certain Measurements and Proportions, with Means in Parentheses, in Males of the Subspecies of Hyla pseudopuma. Subspecies N Snout-vent Length Tibia Length/ S-V L Tympanum / Eye pseudopuma infucata 30 37.6-41.4 0.485-0.550 0.476-0.667 (39.7) (0.515) (0.576) 30 37.6-42.9 0.504-0.569 0.432-0.568 (39.5) (0.534) (0.492) Rica and Pacific slopes of western Panama and H. p. infucata on the Atlantic slopes of western Panama. Minor differences exist in proportions (ta- ble 28), but the major structural difference between the subspecies is in the shape of the snout, which is bluntly rounded in lateral pro- file and acuminate in dorsal profile in infucata and acutely rounded in lateral profile and acuminate in dorsal profile in pseudopuma (fig. 115). The shape of the snout is de- pendent upon the nature of the underlying premaxillaries. In infucata, the premaxillaries lie in a transverse plane and have short, nearly vertical alary processes, whereas in pseudo- puma, the premaxillaries he at a slight angle and have longer alary processes that are in- clined posteriorly. The dorsal color and pattern is highly variable and subject to extreme metachrosis Fie. 115. Lateral views of the heads of (A) Hyla p. pseudopuma (K.U. No. 64884) and (B) H. p. infucata (K.U. No. 101784). x 3. in both subspecies. Nonetheless, the most obvious difference between the subspecies is in color. Hyla p. infucata has bright red flash colors on the thighs and webbing, whereas these surfaces in the nominate subspecies are tan or brown. Distribution: Hyla pseudopuma occurs at moderate to high elevations in the high- lands of Costa Rica and western Panama (fig. 116). Hyla pseudopuma pseudopuma Gunther Hyla pseudopuma Gunther, 1901 (1885-1902), p. 274 [syntypes, B.M.N.H. Nos. 96.10.8.61-67 from La Palma, San Jose Province, Costa Rica; C. F. Under- wood collector; B.M.N.H. Nos. 1902.1.28.25-26 from La Palma, San Jose Province, Costa Rica; donated by the Museo Nacional de Costa Rica], Taylor, 1952c, p. 871. Hyla pseudopuma pseudopuma: Duellman, 1968a, p. 566. Diagnosis: This subspecies of Hyla pseudopuma is distinguished from H. p. in- fucata by having creamy tan or brown anterior and posterior surfaces of the thighs and web- bing ( red in infucata ) and an acuminate snout ( truncate in dorsal profile and bluntly round- ed in lateral profile in infucata ) . Description: Males of this subspecies at- tain a maximum known snout-vent length of 41.4 mm., and females reach 47.6 mm. In a series of 30 males from Tapanti, Cartago Province, Costa Rica, the snout-vent length is 37.6 to 41.4 (mean, 39.7) mm.; the ratio of tibia length to snout-vent length is 0.485 to 0.550 (mean, 0.515); the ratio of foot length to snout-vent length is 0.454 to 0.529 (mean, 0.482 ) ; the ratio of head length to snout-vent length is 0.296 to 0.333 (mean, 0.319); the ratio of head width to snout-vent length is 0.289 to 0.333 (mean, 0.312), and the ratio 264 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 • H. p. pseudopuma O H. p. infucata 50 - 1 KILOMETERS Fig. 116. Distribution of the subspecies of Hyla pseudopuma. of the diameter of the tympanum to that of the eye is 0.476 to 0.667 (mean, 0.576). Eleven females from the same locality have snout-vent lengths of 41.6 to 47.6 (mean, 44.3) mm. and differ from the males only by having a slightly larger tympanum; the ratio of the diameter of the tympanum to that of the eye is 0.579 to 0.714 (mean, 0.620). The head is usually slightly narrower than the body, and the top of the head is barely convex. The snout in dorsal profile is acutely rounded; in lateral profile, it is rounded above and inclined to the margin of the lip in fe- males, and gradually inclined in males (fig. 115A). The snout is moderately long; the slightly protruding nostrils are situated at a point about two-thirds of the distance from the eyes to the tip of the snout; the internarial area is slightly depressed. The canthus is angular; the loreal region is barely concave, and the lips are moderately thick and slightly flared. A moderately heavy dermal fold ex- tends posteriorly from the eye, above the tym- panum, to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance equal to the diameter of the tympanum. The arms are moderately long and robust; an axillary membrane is absent. A row of low tubercles is present on the ventrolateral edge of the forearm, and a thin dermal fold is pres- ent on the wrist. The hands are large, and the fingers are moderately long and robust I!)70 DUELLMAN: HYLID FROGS 265 and bear large discs; the width of the disc on the third finger is equal to the diameter of the tympanum. The subarticular tubercles are large and flattened; the distal tubercles on the third and fourth fingers are weakly bifid in many specimens. The supernumerary tuber- cles are large and numerous on the proximal segments of each digit. A small elevated pal- mar tubercle is present. The prepollex is greatly enlarged and bulbous and in breeding males bears an extensive horny nuptial ex- crescence. The fingers are about one-third webbed (fig. 117A). The webbing is vestigial between the first and second fingers and ex- tends from the base of the penultimate pha- lanx of the second to the base of the ante- penultimate phalanx of the third and from the distal end of the antepenultimate phalanx of the third to the distal end of the antepenulti- mate phalanx of the fourth finger. The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A thin transverse dermal fold is present on the heel, and a weak tarsal fold is present, at least distally. The inner metatarsal tubercle is small, elliptical, and flat. No distinct outer metatarsal tubercle is present. The toes are moderately long and slender and bear discs that are slightly smaller than those on the fingers. The subarticular tubercles are moderately large and subcorneal, and the supernumerary tubercles are large, elevated, and pigmented. The toes are about two-thirds webbed (fig. 117C). The webbing extends from the middle of the penultimate phalanx of the first toe to the distal end of the antepenultimate phalanx of the second, from the middle of the penultimate phalanx of the second to the middle of the antepenultimate phalanx of the third, from the distal end of the penultimate phalanx of the third to the middle of the antepenultimate phalanx of the fourth and on to the distal end of the penulti- mate phalanx of the fifth toe. The anal opening is directed posteroven- trally near the midlevel of the thighs. A short anal sheath is present, and a few large tuber- cles are present below the anal opening. The skin on the throat, belly, and proximal postcro- ventral surfaces of the thighs is granular; else- where, the skin is smooth. The tongue is cordi- form. shallowly notched posteriorly, and not free behind. The dentigerous processes of the prevomers are narrowly separated, transverse or posteromedially inclined, high elevations between the posterior margins of the moder- ately small, quadrangular choanae. Males have four to six ( mean, 4.8 ) and females have five to seven (mean, 5.8) teeth on each pro- cess. The vocal slits extend from the mid- lateral base of the tongue to the angles of the jaws. The vocal sac is median and subgular with a lateral expansion (fig. 118). The general coloration of Hyla pseudo- puma pseudopuma is brown with darker brown markings on the dorsum and transverse bars on the limbs (pi. 52, fig. 5). The anterior and posterior surfaces of the thighs are tan or brown; the flanks are brown with yellow or creamy white spots. The venter is creamy white. The iris is deep bronze. When active at night, most individuals are pale tan with brown or olive-brown markings on the dorsum and thighs and pale yellow spots on the flanks. By day, the dorsum in some individuals is pale gray or yellow with or without distinctive dark markings; the an- terior and posterior surfaces of the thighs are dark brown or black, and the flanks are dark brown or black with bright yellow spots. In some individuals, the axilla and groin are pale blue. In preservative the dorsum is tan, reddish brown, or gray with darker markings. The variation in the dorsal pattern is considerable (fig. 119). In most males, there is a small amount of dark flecking on the edge of the chin and in some males there are brown spots on the skin. Most females have a heavy suf- fusion of brown or gray on the chin. Tadpoles: Large developmental series of tadpoles are available from Tapanti, Cartago Province, and Rio Las Vueltas, Heredia Prov- ince, Costa Rica. A typical tadpole in develop- mental stage 37 has a body length of 11.5 mm. and a total length of 31.0 mm. The body is robust, widest posteriorly, and only slightly wider than deep. In dorsal profile, the snout is round, and in lateral profile, it is inclined anteroventrally from the nostrils. The eyes are small, widely separated, and directed lat- erally. The nostrils are situated at a point 266 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fie. 117. Hands and feet of members of the Hijla pseudopuma group. A and C. Hijla pseu- dopuma pseudopuma, K.U. No. 103722. B and D. Hyla angustilineata, K.U. No. 103583. X 5. 1970 DUELLMAN: HYLID FROGS 267 Fig. 118. Anterior view of the head of a male Hyla p. pseudopuma with vocal sacs expanded, x 3. about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posteriorly at a point be- low the midline about two-thirds of the dis- tance from the snout to the end of the body. The anal tube is short and dextral. The caudal musculature is relatively slender and termi- nates gradually just short of the tip of the rounded tail. The caudal fins are equal in depth, and the dorsal fin does not extend on to the body. At midlength of the tail, the depth of the caudal musculature is equal to the depth of either fin ( fig. 120A ) . The body is dark brown above and below, and the caudal musculature is brown. The fins are transparent but heavily flecked with brown. The iris is bronze. In preservative, the body is dark brown, and the caudal muscu- lature is somewhat paler. The posteromedian part of the venter lacks pigment; elsewhere, the venter is heavily flecked with brown. There is a rather even distribution of brown flecks over the caudal fins. The mouth is ventral and directed antero- ventrally. The mouth is relatively small and has weak lateral folds. The medial part of the upper lip is bare; otherwise, the mouth is bordered by two rows of small, conical pa- pillae. Numerous papillae are present in the lateral folds. The beaks are well developed and bear small, pointed serrations. The upper beak is in the form of a broad arch with long, slender lateral processes. The ventral beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows extend laterally to the edge of the lip, and the first upper tooth row is narrowly interrupted medially. The lower rows are complete and nearly as long as the upper rows (fig. 121A). The development of the tadpoles is dis- cussed in the section on Natural History. Mating Call: The call of Hyla p. pseudo- puma consists of a single, low, poorly modu- lated note or a series of short notes. Seem- ingly, the latter are nothing more than a frag- mented longer note. In a recording of an individual producing normal notes, the note repetition rate is 45 notes per minute; the duration of each note is 0.03 of a second, and Fig. 119. Variation in dorsal color pattern in Hyla pseudopuma pseudopuma. A. K.U. No. 64866. K.U. No. 64893. C. K.U. No. 64889. D. K.U. No. 64902. E. K.U. No. 64879. 268 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 120. Tadpoles of members of the Hyla pseudopuma group. A. Hyla p. pseudopuma, K.U. No. 104147. X 5. B. Hyla angustilineata, K.U. No. 104120. x 3. the pulse rate is 85 pulses per second. The fundamental frequency is 69 cycles per sec- ond and the dominant frequency is 956 cycles per second (pi. 20, fig. 1). Natural History: Hyla pseudopuma Fig. 121. Mouths of tadpoles of the Hyla pseudo- puma group. A. Hyla p. pseudopuma, K.U. No. 104147. B. Hyla angustilineata, K.U. No. 104120. X 25. pseudopuma inhabits humid montane areas in which the frog is active throughout the year. By day, the frogs are secreted in bromeliads or in elephant-car plants. At night, when not breeding, individuals are found sitting on bushes and trees. Apparently there are two breeding seasons each year in this species. Many mating pairs were found at Tapanti, Cartago Province, Costa Rica, on April 29, 1961. At the same locality from mid-May through July no mating activity was observed. Starrett (1960a, p. 22) noted that the species was breeding in large numbers on the southeast slope of Volcan Poas, Alajuela Province, Costa Rica, on August 6, 1957. I have observed calling males at Tapanti in late April and early May, at Cin- chona, Alajuela Province, on April 5, and on the southeastern slopes of Cerro de la Muerte on April 7 and June 17. A biannual breeding season also is evidenced by the times of oc- currence of recently metamorphosed young. Small young were found at Tapanti between June 6 and 29, 1961; many juveniles were found on March 30, 1966, at the Rio Las Vuel- tas in Heredia Province, Costa Rica. Prior to April 19, 1961, the only individuals of Hyla pseudopuma observed at Tapanti were taken from bromeliads and elephant-ear plants by day. On the night of April 19, after a light rain, many males were observed in muddy pools and depressions in a pasture at the edge of a forest; additional males and a few females were found on vegetation at the 1970 DUELLMAN: HYLID FROGS 269 edge of the woods. No males were heard to call. On April 29, 1961, after a heavy rain in the afternoon, Hyla pseudopuma was extreme- ly abundant at Tapanti. Many clasping pairs were found in muddy pools. Amplexus is ax- illary; the male rides far forward on the fe- male, so that the snout of the male is nearly above the nostril of the female. The hind limbs of the male are tucked along the sides of the body. A few clasping pairs were ob- served on land. Of those pairs observed in the water, both males and females have the back arched. The female either has the hands free, usually in a downward position, or holding to a stick, leaf, or blade of grass. The eggs are exuded onto sticks, leaves, and blades of grass (pi. 8, fig. 1). During deposition, the female moves along a leaf, covers it with eggs, and moves to another object and keeps depositing eggs; thus, not all of the eggs are laid together. Many males were observed floating on the sur- face of the water with their hind limbs spread and the arms extended downward. In this position the back is slightly arched. The frogs are fast swimmers with the arms adpressed to the sides of the bodv. Similar observations were made at the same locality on May 2, 1961. Eggs collected on April 29, 1961, hatched the following day. Sixty hours after hatching, the tadpoles were in developmental stages 22 through 24. By 84 hours after hatching, all of the tadpoles were in developmental stage 25. During this stage the tadpoles grow, but do not begin the development of limb buds, which are first apparent in tadpoles 21 days of age. At an age of 35 days, most of the tadpoles were in developmental stages 30 and 31, and at an age of 70 days, the tadpoles var- ied from developmental stage 34 to stage 38. Some of the tadpoles metamorphosed on June 25, after only 57 days of development, whereas most of the tadpoles metamorphosed between July 17 and 19, thereby requiring 79 to 81 days to complete their larval development. The duration of the larval stage correlates well with observations made at Tapanti, where it is assumed that the first breeding possibly took place as early as April 19. Metamorphos- ing young were first observed on June 25 and again on June 29, thus indicating a period of 65 to 69 days for larval development. TABLE 29 Measurements of Tadpoles, with Means in Parentheses, in Relation to Developmental Stages of Hyla p. pseudopuma from Tapanti, Costa Rica. Stage N Body Length Tail Length Total Length 22 __ 3 3.43- 3.50 24 3 3.46- 3.52 25 28 3.15- 5.25 26 21 5.18- 7.00 27 15 6.58- 7.56 28 5 7.42- 8.40 29 3 8.12- 8.54 30 2 7.42- 8.10 31 5 7.42- 8.40 34 ..... 4 8.68- 9.80 35 2 9.60- 9.80 36 10 9.50-11.00 37 6 10.20-11.60 38 3 11.20-11.60 39 2 10.70-10.90 40 3 10.80-11.10 41 1 11.10 43 4 9.80-11.90 ( 46 . 27 10.36-13.72 ( (3.48) (3.50) (4.15) (6.25) (7.08) (7.81) (8.31) (7.76) (7.93) (9.50) (9.70) 10.15) 10.63) 11.43) 10.80) 10.97) 11.03) 12.13) 4.13- 4.66- 4.20- 7.56- 9.52- 11.06- 11.34- 14.00- 12.18- 17.50- 16,30- 16.90- 18.10- 20.60- 19.20- 20.00- 0.09- 4.48 4.72 7.84 10.00 12.32 12.32 16.50 15.90 16.00 17.90 17.60 ( 20.00 ( 22.60 ( 21.30 ( 20.60 ( 23.40 ( 21.80 7.00 (4.27) (4.69) (5.65) (8.96) 10.64) 11.73) 13.34) 14.95) 14.84) 17.70) 16.95) 18.20) 19.92) 20.97) 19.90) 21.33) (2.50) 7.56- 8.12- 7.70- 12.74- 16.52- 18.48- 19.46- 21.42- 19.60- 26.58- 25.90- 26.90- 28.30- 32.20- 30.10- 31.10- 9.80- 7.98 8.24 13.16 17.00 19.88 20.72 25.00 24.00 24.12 27.50 27.40 30.S0 34.20 32.50 31.30 34.40 32.90 18.90 ( (7.75) (8.19) (9.84) 15.21 ) 17.72) 19.54) 21.63) 22.71) 22.76) 27.19) 26.65) 28.36) 30.55) 32.40) 30.70) 32.30) 13.51) 270 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 30 - 25 20 O) 15 1 -Total T T Tail Body 5 Toes - Mouthparts Degenerating Mouthparts Complete L = 1/2D Oral Suckers Present-^ IS •"'' Metamorphosis Complete " \ \ •— ~~ > J I I L 1 ' J L _^L 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 Developmental Stages Fie. 122. Relative rate of growth in tadpoles of Hyla pscudopuma as correlated with developmental stages (table 29). Points are means of measurements given in table 2; formulas for the limb bud refer to its length (L) in relation to basal diameter ( D ) . The eggs are laid in an adherent mass, but the individual eggs and their membranes re- main discreet. Ten eggs in developmental stages 5 through 8 have diameters of 1.62 to 1.85 (mean, 1.71) mm. The diameter of the fertilization membrane is 1.65 to 1.89 (mean, 1.75) mm., and the diameter of the outer en- velope is 4.20 to 5.60 (mean, 4.95) mm. The development and sizes of tadpoles are summarized in table 29 and figure 122. At hatching, the tadpoles are uniform brown in color. The tail bud is well developed, and the gill plate is furrowed. Three visceral arches are apparent. The oral suckers are well de- veloped; the stomodeum is invaginated, but there is no evidence of invagination of the proctodeum. Tadpoles in developmental stage 20 have filamentous gills composed of about 13 unbranched divisions. The oral suckers are still present but the cornea is not yet transpar- ent. The tail is opaque, the myomeres are barely visible in the caudal musculature, and the dorsal fin seems to extend almost to the anterior end of the body. By developmental stage 22 the oral suckers are still well devel- oped, although the mouth is beginning to form anteriorly. The caudal fins are not yet trans- parent; they seem to be covered with a fine pigment. In developmental stage 23, the gills are still present on both sides, and in most in- dividuals, one oral sucker remains obvious and about ten times the size of the others. In the mouth, the beaks are formed, but there is no indication of tooth rows. Small individuals in developmental stage 25 have remnants of oral suckers. The beaks are present and both upper tooth rows are faintly indicated; the second upper row is 1970 DUELLMAN: HYLID FROGS 271 widely interrupted medially. The first and second lower rows are present, and the first row is interrupted medially. The median part of the upper lip is bare, and the entire lower lip lacks papillae. In these tadpoles, the first indication of formation of color pattern is apparent. There is a moderate scattering of discreet arborized cells over the dorsal and lateral surfaces of the body and along the dorsal surface of the caudal musculature. The fins are finely pigmented. During develop- mental stage 25, the oral suckers completely disappear, and the mouthparts completely de- velop. The pigment becomes heavier over the dorsum, and the arborized cells aggregate to form blotches over the entire caudal muscu- lature. The fins become transparent with brown flecks. Tadpoles in developmental stage 41 have lost the cloacal tail piece; the mouth- parts are disintegrating. The third lower tooth row is absent, and the second row is only present in part. Tadpoles in developmental stage 45 have a well-developed adult mouth. The venter is unpigmented except for sparse flecking along the lateral edge of the lower jaw. The limbs are moderately pigmented in the form of transverse bands on the forearms and shanks. In recently metamorphosed young, the dorsum is pale olive-tan with brown markings and pale tan spots. The lips are silvery white. The hind limbs are yellowish tan with brown bars, and the venter is silvery white. Remarks: Hyla p. pseudopuma is one of the most abundant frogs in the hylids of Costa Rica. Because of its apparent generalized morphology and life history, it would be use- ful to study more intensely the biology of this species. Etymology: The specific name is derived from the Greek pseudes, meaning false, and puma, an Indian name for a cat; the name pseudopuma is in reference to the species' general appearance to Hyla (Smihsca) puma. Distribution: Hyla p. pseudopuma occurs at elevations usually between 1000 and 2400 meters in the highlands of Costa Rica and on the Pacific slopes of western Panama (fig. 116). On the Pacific slopes in Costa Rica, this species is known to descend to an elevation of 865 meters. See Appendix 1 for the locality records of the 468 specimens examined. Hyla pseudopuma infueata Duellman Hyla pseudopuma infueata Duellman, 1968a, p. 564 [holotype, K.U. No. 101770 from the Rio Chan- gena, Bocas del Toro Province, Panama, 830 meters; William E. Duellman collector]. Diagnosis: This subspecies of Hyla pseu- dopuma is distinguished from the nominate subspecies by having the webbing of the feet and the anterior and posterior surfaces of the thighs red, instead of tan or brown, and by having a truncate, instead of an acuminate snout. Description: Males of this subspecies at- tain a maximum known snout-vent length of 42.9 mm., and females reach 45.6 mm. In a series of 30 males from the Rio Changena and Rio Claro, Bocas del Toro Province, Panama, the snout-vent length is 37.6 to 42.9 (mean, 39.5) mm.; the ratio of tibia length to snout- vent length is 0.504 to 0.569 (mean, 0.534); the ratio of foot length to snout-vent length is 0.433 to 0.495 (mean, 0.474); the ratio of head length to snout-vent length is 0.297 to 0.329 (mean, 0.319); the ratio of head width to snout-vent length is 0.289 to 0.335 (mean, 0.315), and the ratio of the diameter of the tympanum to that of the eye is 0.432 to 0.568 (mean, 0.492). Eleven females from the same area have snout-vent lengths of 41.1 to 45.6 (mean, 42.6 )mm. In proportions, they differ from the males only by having a very slightly larger tympanum; the ratio of the diameter of the tympanum to that of the eye is 0.435 to 0.56l' ( mean, 0.501 ) . Structurally, this subspecies is like the nominate subspecies, except for the shape of the snout and a slightly smaller tympanum (table 28). The snout in Hyla pseudopuma infueata is short and truncate; in lateral profile the snout is bluntly rounded, whereas in dorsal profile the snout is truncate. The canthus is rounded; the loreal region is barely concave and the lips are thick and moderately flared (fig. 115B). The general coloration of Hyla pseudo- puma infueata is brown above, creamy white below, and red on the hidden surfaces of the hind limbs and feet (pi. 52, fig. 6). In most individuals, the dorsum is yellowish tan with 272 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 olive-brown markings by night and uniform pale yellowish tan by day. The axilla, inner surface of the elbow, groin, anterior and pos- terior surfaces of the thighs, ventral surfaces of the thighs and shanks, inner surfaces of the feet, and dorsal surfaces of the first three toes are tomato red. The flanks are dark blue with yellow spots and reticulations. The throat, chest, and anterior part of the belly are creamy white, whereas the posterior part of the belly is orange, becoming red in the ex- treme posterior region. The throat is flecked with brown. The iris is pale bronze with black reticulations. All specimens have the diagnostic red legs and blue flanks with yellow spots and mot- tling, but the dorsal pattern is highly variable. In most individuals the dark markings on the dorsum are a solid color, but in some speci- mens the borders of the marks are dark, and the interior of the mark is nearly the same color as the rest of the dorsum. A triangular dark mark with the anterolateral corners on the eyelids is present in all specimens. In some individuals, the posteriorly directed apex of this triangular mark is connected to the apex of another triangular mark on the back; in other individuals, the marks are narrowly sep- arated, whereas in a few specimens, the marks are broadly connected. A dark blotch usually is present on the posterior end of the body. One specimen has many small white spots on the dorsum. A narrow transverse white stripe is present above the anus, and the transverse bars on the limbs are present in all specimens although they are indistinct in some individ- uals. The pattern on the flanks varies from three to four large spots to as many as 44 small spots. All males have dark flecks or reticula- tions on the throat; in some individuals, the chest and belly are heavily flecked. Although the amount of flecking is much less in most females, one individual is as heavily flecked on the throat and belly as any male. There is considerable metachrosis in this frog. At night the frogs usually are yellowish tan above with slightly darker dorsal mark- ings. The axilla, groin, and anterior and pos- terior surfaces of the thighs, ventral surfaces of the hind limbs, and webbing on the hands and feet are dark tomato red. Ry day, some individuals become creamy yellow, others ashy white, and others grayish tan. The flanks arc dark blue with yellow spots. In preservative, the dorsum is grayish tan to brown with darker blotches on the back and transverse bands on the limbs. The an- terior and posterior surfaces of the thighs are pinkish tan, and the webbing on the feet is pale gray. The flanks are brown with silvery white spots or reticulations. Numerous small white flecks are present on the heels and the proximal ventral surfaces of the thighs. The throat and belly are creamy white with brown flecks on the chin and in some individuals on the chest and belly. Tadpoles: The tadpoles of this subspecies are unknown. Mating Call: No recordings of the call of this subspecies are available. Calls heard in the field are indistinguishable from those of the nominate subspecies. Natural History: Hyla pseudopuma in- fucata inhabits humid lower montane forests characterized by high rainfall throughout the year. All of the known specimens were ob- tained from such forest. Most individuals were found on bushes and low trees at night, but three males and one clasping pair were found on the ground. Although no breeding was observed, it is presumed that this subspecies breeds in shallow, temporary pools, like those utilized by the nominate subspecies. Remarks: Although intergradation has not been demonstrated, the population here re- ferred to as Hyla pseudopuma infucata cer- tainly seems to be conspecifie with Hyla pseu- dopuma. Both have the same kind of, and variation in, dorsal markings; furthermore, both taxa have conical, pigmented supernu- merary tubercles on the toes, weakly bilobate vocal sacs, and greatly enlarged prepollices bearing horny nuptial excrescences. Etymology: The subspecific name is Latin, meaning painted and refers to the red colors on the limbs and web. Distribution: Presently Hyla pseudo- puma infucata is known only from elevations between S30 and 910 meters on the Caribbean slopes of the Cordillera Talamanca in western Panama (fig. 116). See Appendix 1 for the locality records of the 50 specimens examined. 1970 DUELLMAN: HYLID FROGS 273 Hyla angustilineata Taylor Hyla angustilineata Taylor, 1952c, p. S50 [holo- type, U.S.N.M. No. 75060 from La Palma, San Jose Province, Costa Rica; M. Valerio collector]. Diagnosis: This moderately small species has a brown dorsum ( bright green in juve- niles) with a sharply defined, bright, creamy yellow line from the tip of the snout, through the eye, to the groin, bordered below by a dark brown band. The venter is yellow flecked with black. Other Middle American Hyla hav- ing white dorsolateral stripes (microcephah, picta, robertmertensi, and smithi) are smaller and have a yellow or tan dorsum and lack dark flecks. Hyla thorectes and some populations of Hyla lancasteri have dark spots or mottling on the venter, but these species lack dorsolateral stripes. Description: Males of this moderately small species attain a snout-vent length of 34.2 mm., and females reach 36.S mm. In a series of 12 adult males from the Rio Las Vueltas, on the south slope of Volcan Burba, Heredia Province, Costa Rica, the snout-vent length is 30.6 to 34.2 (mean, 31.5) mm.; the ratio of tibia length to snout-vent length is 0.492 to 0.554 (mean, 0.520); the ratio of foot length to snout-vent length is 0.411 to 0.451 (mean, 0.437); the ratio of head length to snout-vent length is 0.351 to 0.382 (mean, 0.362); the ratio of head width to snout-vent length is 0.352 to 0.375 (mean, 0.359), and the ratio of the diameter of the tympanum to that of the eye is 0.425 to 0.487 (mean, 0.456). Three fe- males from the same locality have snout-vent lengths of 34.1 to 36.8 (mean, 35.1) mm. In proportions, they differ from the males only by having a slightly larger tympanum; the ratio of the diameter of the tympanum to that of the eye is 0.450 to 0.536 (mean, 0.490). The head is as wide as, or slightly wider than the body, and the top of the head is slightly convex. In dorsal profile, the snout is acutely rounded; in lateral profile it is round. The snout is moderately long; the nostrils are barely protuberant at a point about three- fourths of the distance from the eyes to the tip of the snout; the internarial area is not noticeably depressed. The canthus is angular; the loreal region is barely concave, and the lips are moderately thick, but barely flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, to a point near the in- sertion of the arm. The fold obscures the up- per edge of the tympanum, which otherwise is distinct and separated from the eye by a distance nearly equal to twice the diameter of the tympanum. The arms are moderately long and slender; an axillary membrane is absent. There are a few small tubercles on the ventrolateral edge of the forearm, but these do not form a con- tinuous row; a thin transverse dermal fold is present on the wrist. The hand is large; the fingers are moderately long and robust and bear large discs; the width of the disc on the third finger is slightly greater than the diam- eter of the tympanum. The subartieular tuber- cles are large and flattened; the distal tubercle on the fourth finger usually is bifid. The su- pernumerary tubercles are large and conical. A large elevated, bifid, palmar tubercle is pres- ent. The prepollex is moderately enlarged and in breeding males bears a horny nuptial excres- cence. The fingers essentially lack webbing (fig. 117B). The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation ex- tends to the anterior corner of the eye. Two small tubercles and a thin transverse dermal fold are present on the heel, but a distinct tarsal fold is lacking. An inner metatarsal tu- bercle is large, flat, and elliptical. The outer metatarsal tubercle is small and subcorneal. The feet are relatively small with short toes that have discs that are only slightly smaller than those on the fingers. The subartieular tu- bercles are relatively large and flattened, and the supernumerary tubercles are large, coni- cal, and pigmented. The toes are about one- half webbed (fig. 117D). The webbing is vestigial between the first and second toes, but extends from the base of the penultimate phalanx of the second to the base of the ante- penultimate phalanx of the third, from the base of the penultimate phalanx of the third to the base of the antepenultimate phalanx of the fourth and on to the base of the penulti- mate phalanx of the fifth toe. The anal opening is directed posteroven- trally just above the midlevel of the thighs. The anal sheath is short; several large tuber- cles are present below the anal opening. The 274 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 skin on the throat, belly and proximal postero- ventral surfaces of the thighs is strongly granu- lar; elsewhere, the skin is smooth. The tongue is cordiform, shallowly notched posteriorly, and not free behind. The dentigerous pro- cesses of the prevomers are narrowly sepa- rated, transverse or posteromedially inclined, high elevations between the posterior margins of the moderately large ovoid choanae. Males have three to five (mean, 4.1) teeth on each process and a total of six to 10 (mean, 8.3) prevomerine teeth; females have four or five teeth on each process and a total of nine or 10 (mean, 9.3) prevomerine teeth. The vocal slits extend from the posterolateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla angusti- lineata consists of a pale brown or olive-tan dorsum with a thin white dorsolateral line (pi. 52, fig. 3). The dorsum of the head and body is pale brown or olive-tan with a bronze hue. The lips are a bronze-tan. A thin white line extends from the tip of the snout, along the canthal ridge and edge of the upper eyelid and above the tympanum, to the insertion of the hind limb. The flanks are dark brown. The dorsal surfaces of the limbs are colored like the back and are marked by small dark brown spots. Numerous small brown spots usually are present on the back. The groin, ventral surfaces of the legs, anterior and pos- terior surfaces of the thighs, and the webbing on the feet are dull yellow. The throat and belly are creamy white. All ventral surfaces are heavily spotted with dark brown. The iris is reddish copper. Juveniles having a snout-vent length of less than 25 mm. are colored noticeably dif- ferent from the adults. The dorsum is bright leaf green and the dorsolateral stripe is white. The flanks are dark brown and the lips are pale green ( pi. 52, fig. 4 ) . The chin and belly are creamy white with black flecks. The limbs are tan with dark brown markings. In preservative, the dorsum is dull brown or tan. The thin white stripe separates the dor- sal color from the dark brown on the flanks. The dorsal surfaces of the limbs are pale brown with dark brown flecks or indications of transverse marks. The venter is creamy tan, heavily flecked with brown. Tadpoles: A typical tadpole in develop- mental stage 25 has a body length of 13.4 mm. and a total length of 33.1 mm. The body is robust, widest posteriorly, and as deep as wide. In dorsal profile, the snout is round; in lateral profile, it slopes gradually from the eye to a truncate tip. The eyes are small, widely separated, and directed dorsolaterally. The nostrils are directed anterolaterally at a point about midway between the eyes and the tip of the snout. The opening of the sinistral spir- acle is directed posteriorly at a point on the midline at about midlength of the body. The anal tube is short and dextral. The tail is short, slightly more than twice the length of the body. The caudal musculature is rela- tively slender and tapers gradually to a point just short of the rounded tip of the fin. The fins are moderately deep; the dorsal fin is slightly deeper than the ventral one and does not extend on to the body. At midlength of the tail, the depth of the caudal musculature is slightly less than the depth of either fin ( fig. 120B). The body is mottled brown and bronze-tan. The tail is creamy tan with dark brown mark- ings on the musculature and fins. The iris is deep bronze. In preservative, the body is uni- formly dark brown. The caudal musculature is cream with brown markings. The dorsal edge of the caudal musculature on the proxi- mal half of the tail is dark brown. This gives the appearance of a narrow brown stripe when viewed laterally. Elsewhere, on the caudal musculature, the dorsal fin, and the posterior one-third of the ventral fin, there are small brown flecks. The mouth is relatively small and directed ventrally- Shallow lateral folds are present in the lips, which are bare anteromedially, but elsewhere bordered by two rows of small pa- pillae. The beaks are well-developed and bear short, pointed serrations. The upper beak is in the form of a broad arch with long, slender lateral processes. The lower beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows are long, and the second upper row is narrowly inter- rupted medially. The three lower rows are 1970 DUELLMAN: HYLID FROGS 275 equal in length, but shorter than the upper rows, and complete (fig. 121B). Mating Call: The call of Hyla angusti- lineata consists of a pair of short, pulsed, poorly modulated notes. In the one recording available, the interval between call groups varies from 72 to SO seconds. The duration of each note varies from 0.07 to 0.14 of a second. The notes have 90 pulses per second, a funda- mental frequency of 87 cycles per second, and a dominant frequency of 1653 cycles per second (pi. 20, fig. 2). Natural History: Hyla angustilineata in- habits humid upper montane forests, where it breeds in water-filled depressions. In March and April, 1966, males were calling sporadi- cally around water-filled depressions in an overgrown meadow adjacent to oak forest on Volcan Barba. The presence of numerous tad- poles in the ponds at that time, as well as the presence of several recently metamorphosed young, indicates that this species either breeds more than once each year or that the breeding season had long since past in this species. However, in April, 1966, one gravid female was obtained. Seven recently metamorphosed young have snout-vent lengths of 15.1 to 18.9 (mean, 17.4) mm.; they were colored like the juveniles de- scribed previously. Remarks: The tadpoles of this species are extremely generalized, like those of Hyla pseudopuma. On the basis of larval structure and the generalized cranial features, Hyla an- gustilineata has been grouped with Hyla pseudopuma. Fig. 123. Distribution of Hyla angustilineata. 276 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Etymology: The specific name is derived from the Latin angustus, meaning narrow, and the Latin lineatus, meaning of a line, and refers to the narrow dorsolateral line char- acteristic of this species. Distribution: Hyla angustilineata is known from three localities (elevations be- tween 1500 and 2200 meters) in humid mon- tane forests in the Cordillera Central of Costa Rica (fig. 123). See Appendix 1 for the locality records of the 36 specimens examined. The Hyla rivularis Group Definition: The members of this group are small, stream-breeding species; males at- tain a maximum snout-vent length of 34 mm. and females, 43 mm. The dorsum is green, tan or mottled dark green and black. The posterior surfaces of the thighs are yellow or dark brown with or without contrasting mark- ings. The palpebral membrane is clear. The fingers are no more than one-third webbed, and the toes are about two-thirds webbed. Dermal fringes and appendages are lacking on the limbs, and a distinct axillary membrane is absent. Males have single, median, sub- gular vocal sacs and horny nuptial excres- cences on the pollices. The cranial elements are moderately well-ossified; a large fronto- parietal fontanelle is present, and the sphen- ethmoid is large and extends anteriorly be- tween the nasals. The quadratojugal is absent or reduced to a small spur. The nasal lacks a maxillary process, and the pterygoid does not have a bony articulation with the prootic. Prevomerine teeth are present. The tadpoles have a long, terminally rounded tail and a large, ventral mouth with deep lateral folds and two upper and three lower rows of teeth. The mating call consists of series of short, quickly repeated notes. The haploid number of chromosomes is 12 (known only in H. rivu- laris and tica). Composition: Four species (H. debilis, rivularis, tica, and xanthosticta) comprise the group, which is endemic to lower Central America. All of the species, as now recog- nized, are monotypic. Of the four species, 421 preserved frogs, nine skeletons, and 27 lots of tadpoles were examined. Comments: Starrett (1966) suggested that Hyla debilis, pictipes, rivularis, and tica comprised one species group, that possibly also included Hyla legleri, rufioculis, and uranochroa. Duellman (1968a) named H. xanthosticta and placed the new species in the Hyla pictipes group. Consideration of osteo- logical and larval features, plus characteristics of the mating calls has necessitated the recog- nition of three groups of species, all of which were tentatively placed in the Hyla pictipes group by Starrett. Hyla pictipes differs from the four species here included in the Hyla rivularis group by having a broader skull with a smaller fronto- parietal fontanelle ( a consequence of medial growth of the frontoparietals ) , a much shorter sphenethmoid that does not extend anteriorly between the nasals, and a more slender ptery- goid (figs. 124 and 133). Furthermore, the mating call of pictipes is a single, pulsed, low- pitched note, noticeably different from the series of short, rather high-pitched notes pro- duced by members of the Hyla rivularis group. The Hyla uranochroa group has different larval and osteological conditions; the iris is red, and the mating calls are different from Fig. 124. Dorsal (A) and lateral (B) views of the skull of Hyla tica, K.U. No. 77691. x 7. 1970 DUELLMAN: HYLID FROGS 277 the Hijla rivularis group and Hyla pictipes (see definition of the Hyla uranochroa group for details ) . Fie. 125. Dorsal views of the anterior part of the skulls of members of the Hyla rivularis group showing the position and shape of the sphenethmoid. A. H. tica, K.U. No. 77691. B. H. rivularis, K.U. No. 68610. C. H. debilis, K.U. No. 104323. Approx. x 5. Thus, I conclude that although Hyla pic- tipes is related to the Hyla rivularis group, pictipes represents a divergent line from the Hyla rivularis group-stock. Hyla tica seems to be the most primitive member of the group. This supposition is supported by its relatively short sphenethmoid, more variable mating call, and broad altitudinal distribution. The other species in the group can be derived from Hyla tica by a decrease in size (table 30), increase in length of the sphenethmoid (fig. 125), and divergence of the mating call into the lower (rivularis) and higher (debilis) frequencies (table 31, pi. 2). The anterior extension of the sphenethmoid in rivularis and debilis is reflected externally in the angularity of the protruding snout in these species, whereas the snout is round in tica. The struc- ture of the hands and feet is nearly alike in the four species, most of which have a double or bifid distal subarticular tubercle on the fourth finger (figs. 126 and 127). Few structural differences exist among the tadpoles (figs. 128 and 129). The geographical distribution of Hyla tica encompasses the known ranges of the other species, except for the apparent ab- sence of tica on the Atlantic slopes in western Panama, an area included in the ranges of debilis and rivularis. The four species are partially segregated altitudinally. Hyla debilis occurs at moderate TABLE 30 Comparison of Sizes and Certain Proportions, with Means in Parentheses, of the Species in the Hyla rivularis Group. Species Sex H. tica S 9 H. rivularis <5 9 H. debilis $ 9 H. xanthosticta 9 N Snout-vent Length Tibia Length/ S-V L Head Width/ S-V L Tympanum/ Eye 38 27.4-34.1 0.493-0.527 0.297-0.336 0.462-0.594 (31.8) (0.511) (0.323) (0.517) 12 33.6-42.7 0.497-0.521 0.289-0.340 0.514-0.588 (37.6) (0.508) (0.324) (0.542) 25 29.9-34.0 0.443-0.489 0.311-0.334 0.303-0.455 (32.3) (0.463) (0.323) (0.367) 6 33.4-36.4 0.439-0.482 0.316-0.329 0.361-0.455 (35.7) (0.460) (0.328) (0.409) 20 25.1-29.5 0.461-0.515 0.284-0.328 0.452-0,593 (26.6) (0.485) (0.308) (0.535) 5 26.8-31.6 0.452-0.499 0.287-0.331 0.485-0.581 (29.9) (0.476) (0.316) (0.538) 1 29.3 0.553 0.352 0.500 278 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 126. Hands of the species of the Hyla rivularis group. A. H. tica, K.U. No. 103760. B. H. rivularis, K.U. No. 103735. C. H. debilis, K.U. No. 101567. D. H. xanthosticta, K.U. No. 103772. x 6. elevations (910 to 1450 meters), whereas rivu- laris occurs at elevations of 1280 to 2840 meters and tica at 835 to 1920 meters; Hyla xantho- sticta is known only from one locality at 2100 meters on Volcan Barba, Costa Rica. Although their altitudinal distributions narrowly over- lap, I do not know of rivularis and debilis hav- ing been found sympatrically. Hyla tica oc- curs sympatrically with rivularis and debilis, and rivularis occurs at the only locality where xanthosticta has been found. Hyla tica Starrett Hyla tica Starrett, 1966, p. 23 [holotype, U.M.M.Z. No. 122482 from a stream on Volcan Turrialba, Car- tago Province, Costa Rica, 1400 meters; Andrew and Priscilla Starrett and Thomas M. Uzzell, Jr. collectors]. Diagnosis: Hyla tica differs from other members of the Hyla rividaris group by hav- ing a tuberculate dorsum, mottled dorsal col- oration, distinct transverse bands on the limbs, and rounded snout in lateral profile. Hyla pic- tipes is similar in general appearance but has 1970 DUELLMAN: HYLID FROGS 279 Fig. 127. Feet of the species of the Hijla rivulahs group. A. H. tica, K.U. No. 103760. B. H. rivularis, K.U. No. 103735. C. H. dehilis, K.U. No. 101567. D. H. xanthosticta, K.U. No. 103772. X 6. 280 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fie. 128. Tadpoles of the species of the Hyla rivularis group. A. H. tica, K.U. No. 104127. B. H. rivularis, K.U. No. 104156. C. H. debilis, K.U. No. 104239. X 3. an acutely angular snout in lateral profile and dark flanks and posterior surfaces of the thighs with creamy white or yellow spots, instead of dull tan posterior surfaces of the thighs and mottled flanks. Furthermore, the tympanum is much smaller in pictipes than in tica; the average ratio of the diameter of the tympanum to that of the eye in pictipes is 0.377 and in tica, 0.517. Other Middle American hylids that might be confused with tica are Hyla lan- casteri, Smilisca baudinii and S. sila. Each of these has a barred lip and more webbing in the hand. The former has bold black spots on the flanks and thighs; Smilisca has paired subgular vocal sacs, and S. baudinii has creamy yellow flanks with black mottling, whereas S. sila has small blue spots on the flanks and posterior surfaces of the thighs. Description: This is the largest species in the Hyla rivularis group. Males attain a maxi- mum snout-vent length of 34.1 mm. (mean, 21 specimens from central Costa Rica, 31.6 mm.), and females reach a maximum snout- vent length of 42.7 mm. ( mean, six specimens from central Costa Rica, 38.9 mm.). In the sample of males from central Costa Rica, the ratio of tibia length to snout-vent length is 0.493 to 0.527 (mean, 0.511); the ratio of foot length to snout-vent length is 0.435 to 0.477 (mean, 0.453); the ratio of head length to snout-vent length is 0.294 to 0.327 (mean, 0.308); the ratio of head width to snout- vent length is 0.297 to 0.336 (mean, 0.323), and the ratio of the diameter of the tympanum to that of the eye is 0.462 to 0.594 (mean, 0.517). There is no apparent geographic variation in size and proportions; specimens from western Panama are essentially like those from central Costa Rica. Females are noticeably larger than the males; the smallest female (snout- vent length, 33.6 mm.) is only slightly smaller than the largest male (snout-vent length, 34.1 mm. ) . The head is slightly narrower than the body and slightly longer than wide; the top of the head is barely convex. The snout is short, acutely rounded in dorsal profile and bluntly rounded in lateral profile. The nostrils are barely protuberant and are situated about three-fourths the distance from the eyes to 1970 DUELLMAN: HYLID FROGS 281 Fig. 129. Mouths of tadpoles of the species of the Hyla rivularis group. A. H. tica, K.U. No. 104127. B. H. rivularis, K.U. No. 104156. C. H. dehilis, K.U. No. 104239. x 12. the tip of the snout. The canthus is angular and distinct; the loreal region is deeply con- cave, and the lips are moderately thick and flared. A heavy supratympanic fold extends from the posterior corner of the eye to a point above the insertion of the arm; a thinner der- m W ►J PQ < -a a; cj .He X o-^ ra ^- o = E W a 3 O Jh a 3 O ." _ - '■ *K •3 3 a S o" o a ^ O eg 3 5 Q£ **■» t- £ &> * CD S CD CS = nu _c Oh w 60 O V M-i 3 O" O c 2"2 ■20§ It!— cd 0) CD M w .£ g*u — a K cd t-> a Ph C 3 = 7 a .9 0-0 «o 0 3_ CJ <^~ CD a) ^3 4-1 ^ n a CD 3 W5 a £ *3 cu ^ U o33 60 Z.Q a *.o CTS S £ Mh o en U • ■- +-» c/l t. CD -w o d M 03 -G u to .2 '6 eg a C/J o -t — ' 9 S ° °? M c? § "? & © ^-" — I --^ CO ' — ' © ^~d t1 (D t- O -CD ■—* "t in "5 «= i-H © —I © cc 0 1 — 1 © CO CI 50 ■ — © CI 1 — 1 CO d c 10 1— 1 d d d £U ^co 10 00 ^ <*? i> © ^3 in 10 00 282 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 mal fold extends from the angle of the jaw to the posterior terminus of the supratympanic fold. The upper edge of the tympanum is cov- ered by the supratympanic fold; otherwise, the tympanum is distinct. The tympanum is situated posterior to the eye and is separated from the eye by a distance slightly less than the diameter of the tympanum. The arms are moderately long and robust. A moderate axillary membrane is present, but a thoracic fold is lacking. A tuberculate der- mal ridge is present on the ventrolateral edge of the forearm and the fourth finger; a dis- tinct transverse fold is present on the wrist. The fingers are short and broad and bear large discs; the width of the disc on the third finger is half again the size of the diameter of the tympanum. The subarticular tubercles are moderately small and conical. The distal tu- bercle on the fourth finger is divided in all specimens, whereas that on the third finger is either divided or bifid. A few moderately large, subcorneal supernumerary tubercles are present on the proximal segments of the third and fourth fingers. Two small, distinct outer palmar tubercles are present. The prepollex is moderately enlarged and in breeding males bears a small, brown, horny nuptial excres- cence. The fingers are about one-third webbed (fig. 126A). Only a vestige of a web is present between the first and second fingers; the web extends from the penultimate phalanx of the second to the base of the antepenultimate pha- lanx of the third, and from the distal end of the antepenultimate phalanx of the third to the base of the penultimate phalanx of the fourth finger. The hind limbs are moderately short and robust; the adpressed heels barely overlap. The tibiotarsal articulation extends to the anterior corner of the eye. A tarsal fold is lacking. In some specimens a few small tu- bercles form a row along the outer edge of the tarsus. The inner metatarsal tubercle is low, barely rounded, and ovoid; it is broadly visible from above. A small, conical outer metatarsal tubercle is present. The toes are moderately long and robust and bear discs that are no- ticeably smaller than those on the fingers. The subarticular tubercles are large and round; small, subcorneal supernumerary tu- bercles are present on the proximal segments of all digits. The toes are about two-thirds webbed (fig. 127A). The web extends from the base of the penultimate phalanx of the first toe to the distal end of the antepenulti- mate phalanx of the second, and from the distal end of the penultimate phalanx of the second to the distal end of the antepenulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth, and from the base of the penulti- mate phalanx of the fourth to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- itrally near the mid-level of the thighs and is covered by a short anal sheath. The skin on the dorsal surfaces is smooth with many low, rounded tubercles, that are especially numer- ous in the occipital and sacral regions. The skin on the throat, belly, and posteroventral surfaces of the thighs is granular, whereas that on the other ventral surfaces is smooth. The tongue is cordiform, nearly as broad as long, shallowly notched posteriorly, and bare- ly free behind. Males have a total of seven to 1 1 ( mean, 9.0 ) prevomerine teeth, and females have 13 or 14 ( mean, 13.3 ) prevomerine teeth situated on small transverse ridges between the posterior margins of the small, triangular choanae. The vocal slits extend from the mid- lateral base of the tongue to the angles of the jaws. The vocal sac is single, median, sub- gular, and not greatly distensible. The general coloration of Hyla tica is mot- tled green and brown dorsally with distinct brown transverse bands on the limbs (pi. 53, fig. 1 ) . The dorsal ground color varies from a pale olive-green to tan. The dorsal markings consist of small, irregularly-shaped blotches, many of which usually are interconnecting, and small dark brown flecks. The flanks are dark brown with grayish white spots or tan or green- ish tan with dull white spots that are narrowly surrounded by dark brown. There are four or five narrow dark transverse bands on the thigh, three or four bands on the shank and two or three on the tarsus and forearm. The posterior surfaces of the thighs are brown, orange-brown, or tan, with or without yellow- ish tan flecks on the posterodorsal surface. The lips are dull olive-brown or dark brown with grayish white or greenish white spots along the margin. The venter is dull white, 1970 DUELLMAN: HYLID FROGS 283 usually with a gray suffusion, especially on the chest and laterally on the belly. The iris is dull reddish bronze. When active at night, the dorsum is either dull tan or dark brown with scattered metallic green flecks. By day the green pigment ex- pands to form the coloration described above. Specimens from the eastern part of the range, in western Panama, usually have the posterior surfaces of the thighs a darker color, that is brown or orange-brown, than do those speci- mens from central Costa Rica, where the pos- terior surfaces of the thighs are tan or yellow- ish tan. However, some individuals from cen- tral Costa Rica have dark brown posterior sur- faces of the thighs; in some of these, yellowish tan flecks are present. In preservative, the dorsum is pale brown or grayish brown with darker brown markings. The white spots persist on the flanks. The venter is dull creamy white with a grayish suffusion. Tadpoles: The largest tadpole available is in developmental stage 43 and has a body length of 15.0 mm. and a total length of 40.5 mm. A typical tadpole in developmental stage 34 from Tapanti, Cartago Province, Costa Rica, has a total length of 37.7 mm. and a body length of 12.0 mm. The body is de- pressed and much wider than deep; it is wid- est just behind the eyes. In dorsal profile the snout is broadly rounded, and in lateral profile it is acuminate. The nostrils are directed an- terodorsally and are situated about midway between the eyes and the tip of the snout. The eyes are small and directed dorsolaterally. The mouth is large and directed ventrally. The belly is flat. The spiracle is sinistral and situ- ated ventrolaterally about midway between the eye and the posterior edge of the body. The anal tube is short and dextral. The tail is long, three times the length of the body, shallow, but with heavy caudal musculature, which in dorsal view does not grade gradually into the body, but is distinctly demarked from the posterior edge of the body. The fins are shallow, and at midlength of the tail the cau- dal musculature is deeper than either of the caudal fins. The dorsal fin does not extend onto the body, and posteriorly the caudal fins are rounded. The caudal musculature is ro- bust throughout its length and terminates just before the end of the caudal fin (fig. 128A). The body is brown above and silvery gray below. The snout is tan. The tail is creamy tan with brown transverse markings dorsally and brown reticulations laterally. The fins are transparent with brown flecks, except on the anterior half of the ventral fin. The iris is bronze. In preservative, the body is dull brown above and transparent below. The tail is creamy white with grayish brown markings. The mouth is large and as wide as the body. Well-developed lateral folds are pres- ent. The mouth is completely surrounded by labial papillae; two small rows and one inter- nal large row are present on the upper lip, and four to six rows of papillae are present on the lower lip; only one row of papillae is pres- ent laterally, and the lateral folds are devoid of papillae. The beaks are slender; the upper beak is in the form of a broad arch that is in- dented medially and lacks lateral processes; the lower beak is broadly V-shaped. Both beaks bear minute serrations. There are two upper and three lower rows of teeth. The teeth in the upper rows are larger than those in the lower rows; all of the rows are approxi- mately equal in length and are complete (fig. 129A). Mating Call: The call of Hyla tica con- sists of a series of cricket-like chirps. Each call group consists of three to five notes and the call groups are repeated at intervals of about 1.5 seconds. There are two to four pulses in each call. In the audiospectrograms, several harmonics are visible; two of these (approximately at 2225 and 4750 cycles per second) are emphasized nearlv equally (pi. 21, fig. 1). Natural History: Hyla tica inhabits cloud forests. In these moist environments, the frogs apparently are active throughout the year. Individual frogs have been found on vegetation at the edges of streams in both the rainy season and the dry season, but breeding activity seems to be concentrated in the drier months of the year. Calling males and gravid females have been obtained in February, March, and April. The males call from rocks in the streams or from the branches of bushes and trees overhanging the streams. Usually calling males are found only above fast 284 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 stretches of water; they usually are absent from the borders of quiet pools in the streams. Tadpoles were found in a small, rocky, gravel-bottomed stream at Tapanti, Cartago Province, Costa Rica, on March 26, 1966. The tadpoles adhered to the lee sides of rocks on the bottom of pools. When the tadpoles were disturbed, they moved away rapidly to another rock or took shelter in the debris at the bottom of the pool. Metamorphosing young have been found at Tapanti on April 19, April 29, and June 6. These juveniles were found on leaves of bushes near the stream at night. One com- pletely metamorphosed individual had a snout- vent length of 18.4 mm.; five individuals hav- ing tail stubs five to 11 mm. in length had snout-vent lengths of 17.3 to 19.3 (mean, 18.3) mm. The completely metamorphosed indi- vidual had a dark brown dorsum with metallic green flecks. The dorsal surfaces of the limbs were coppery tan with dark brown bands. The flanks, anterior and posterior surfaces of the thighs, and ventral surfaces of the limbs were yellow. The belly was yellowish white, and the chest, throat, and upper lips were white. As noted by Starrett (1966) the females contained large (2 mm.) unpigmented eggs. Probably the eggs are deposited in the streams. Remarks: Hijla tica seemingly replaces Hyla pictipes at lower elevations. The two species have not been collected along the same stream. Contrariwise, Hyla tica altitudi- nally overlaps the distribution of Hyla rivu- laris and debilis. At Cinchona, Alajuela Prov- ince, Costa Rica and at several localities in Chiriqui Province, Panama, Hyla tica and rivularis have been found breeding at the same time in the same stream. Likewise, Hyla tica and debilis breed in the same stream at Tapanti, Costa Rica. Etymology: The specific name tica is de- rived from the local name "tico," used for the inhabitants of Costa Rica. Distribution: Hyla tica inhabits the cloud forests and lower montane forests at elevations from 835 to 1920 meters in the Cordillera Cen- tral and the Cordillera de Talamanca in Costa Rica and western Panama (fig. 130). In Costa Rica, the species is known from both the At- lantic and the Pacific slopes of the aforemen- tioned mountain ranges, but in Panama, it has been found only on the Pacific slopes in the extreme western part of the country. See Appendix 1 for the locality records of the 113 specimens examined. Hyla rivularis Taylor Hyla rivularis Taylor, 1952c, p. 847 [holotype, K.U. No. 28197 from Isla Bonita, Heredia Province, Costa Rica; Richard C. Taylor and Edward H. Taylor collectors]. Diagnosis: This small species has a tan, yellowish tan, or pale gray dorsum with darker markings that usually are irregularly longi- tudinal, but form transverse marks in some in- dividuals. The thighs, upper arms, flanks, and venter are creamy yellow; the venter and flanks usually are heavily flecked with brown or black. This general coloration, plus the absence of white stripes on the lip and limbs or above the anus distinguish rivularis from all other Middle American hylids. Description: This is a moderately small frog; males attain a maximum snout-vent length of 34.0 mm., and females reach 36.4 mm. In a sample of 25 males from the north slopes of Cerro Pando, Bocas del Toro Prov- ince, Panama, the snout-vent length is 29.9 to 34.0 (mean, 32.3) mm.; the ratio of tibia length to snout-vent length is 0.443 to 0.490 (mean, 0.463); the ratio of foot length to snout-vent length is 0.400 to 0.460 (mean, 0.428); the ratio of head length to snout-vent length is 0.300 to 0.329 (mean, 0.313); the ratio of head width to snout-vent length is 0.311 to 0.333 (mean, 0.323), and the ratio of the diameter of the tympanum to that of the eye is 0.303 to 0.455 (mean, 0.367). In six females from the same locality, the snout- vent length is 34.4 to 36.4 (mean, 35.7) mm. The ratio of the diameter of the tympanum to that of the eye is 0.361 to 0.455 (mean, 0.409); there are no noticeable differences in other proportions between the males and the females. Although minor differences in size and proportions occur throughout the range, there does not seem to be any consistent geo- graphic variation in these characters. The head is as wide as the body and the top of the head is flat or slightly convex. In dorsal profile the snout is acutely rounded; in lateral profile the snout is acutely rounded anterodorsally and is inclined posteroventrally to the lip. The snout is moderately short; the 1970 DUELLMAN: HYLID FROGS 285 83° — I — • H. tica ■ H xanthosticta Fig. 130. Distribution of Hyla tica and Hijla xanthosticta. nostrils are not noticeably protuberant and are situated about three-fourths the distance from the eyes to the tip of the snout. The canthus is strongly angular; the loreal region is noticeably concave, and the lips are mod- erately thick and barely flared. A thin dermal fold extends posteriorly from the posterior corner of the eye to a point above the insertion of the arm; the fold obscures the upper edge of the tympanum. If the tympanic ring is present at all, only the ventral part is evident. The rest of the tympanum is barely discernible beneath the skin. The tympanum is postero- ventral to the eye and separated from the eye by a distance equal to about two-thirds the diameter of the tympanum. The arm is moderately short and robust; a brief axillary membrane is present. A row of tubercles form a low dermal ridge along the ventrolateral edge of the forearm. A distinct transverse fold is present on the wrist. The fingers are short and broad and have large discs, the diameter of the disc on the third finger is usually slightly larger than the diam- eter of the tympanum. The subarticular tuber- cles are either bifid or completely divided in most specimens; in some individuals some tubercles are single, especially on the third finger. The supernumerary tubercles are large, conical, and rather broad; these tubercles are scattered irregularly on the basal segments of each digit and on the median digits are ar- ranged in one or two rows. A rather small, bifid outer palmar tubercle is present. The prepollex is moderately enlarged; breeding males have a nuptial excrescence composed of 286 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 many spinules. The fingers are no more than one-third webbed (fig. 126B). The web is vestigial between the first and second fingers and extends from the base of the penultimate phalanx of the second to the base of the ante- penultimate phalanx of the third finger; from the middle of the antepenultimate phalanx of the third, the web extends to the base of the penultimate phalanx of the fourth finger. The hind limbs are moderately short and robust; the adpressed heels overlap by about one- fifth the length of the shank. The tibiotarsal articulation extends to the posterior corner of the eye. The tarsal fold is lacking. A thin, scalloped dermal fold extends from the heel along the outer edge of the foot to the base of the fifth toe. The inner metatarsal tubercle is ovoid, flat, and broadly visible from above. The outer metatarsal tubercle is small and conical. The toes are moderately short and robust; the discs are only slightly smaller than those on the fingers. The subarticular tuber- cles are moderately large, round, and subcorn- eal; the supernumerary tubercles are arranged in a single row on each digit and are nearly as large as the smaller subarticular tubercles. The toes are about two-thirds webbed (fig. 127B). The web extends from the base of the penultimate phalanx of the first to the base of the penultimate phalanx of the second toe, from the middle of the penultimate phalanx of the second to the base of the antepenultimate phalanx of the third, from the base of the penultimate phalanx of the third to the base of the antepenultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. A narrow fringe ex- tends along the outer edge of the fifth toe. The anal opening is directed posteroven- trally near the level of the upper edges of the thighs. No distinct anal sheath is present; the anal opening is surrounded, except dor- sally, by moderately large tubercles. The skin on the chest, belly, and posteroventral proxi- mal surfaces of the thighs is coarsely granular; elsewhere, the skin is smooth. A faint thoracic fold is present. The tongue is broadly cordi- form, shallowly notched posteriorly and only barely free behind. In a sample of 25 males from the north slope of Cerro Pando, Bocas del Toro Province, Panama, the total number of prevomerine teeth is four to eight (mean, 7.1), and in six females the number of pre- vomerine teeth is nine to 12 (mean, 10.8). There arc two to six teeth on each of the small rounded prevomerine processes situ- ated between the moderately small, ovoid in- ner naries. The vocal slits extend from the mid-lateral base of the tongue to the angle of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Hyla rivularis is pale yellowish tan with faintly darker dorsal markings (pi. 53, fig. 2). When active at night, the frogs usually are pale yellowish tan with the dorsal markings barely discernible. By day, the dorsum is olive-tan to yellowish tan with olive-brown to brown markings. The anterior and posterior of the thighs are pale olive-brown to yellowish brown. The belly is creamy yellow with dark brown or black flecks. The iris is bronze with fine black re- ticulations. The vocal sac is pale creamy yel- low. The dorsal markings consist of a chevron- shaped interorbital bar and irregularly shaped markings on the back that usually form a longitudinal pattern, consisting of a pair of dark marks that may be discreet or intercon- nected. In some individuals, a median dark mark is present in the scapular region, and in some others there is a transverse dark mark above the anus. The dorsal surfaces of the thighs and shanks are colored like the dorsal surfaces of the body; in some specimens faint transverse bands are visible on the dorsal sur- faces of the shanks. In many specimens, small dark brown flecks are present on the dorsal surfaces of the shanks and feet. A narrow creamy white line is present on the ventro- lateral edge of the forearm; a white line ex- tends from the heel to the base of the fifth toe. In approximately half of the specimens a short white anal stripe is present; in most of these, the tubercles bordering the anal opening also are white. The ventral surfaces of the hind legs are dull yellowish tan. In some individuals from throughout the range, but especially in western Panama, bright me- tallic green flecks are scattered on the dorsum. All individuals have some dark spots on the venter; in some specimens, the spots are nu- merous and rather large; in others, they are few in number and small. In many individuals the dots are present also on the ventral sur- 1970 DUELLMAN: HYLID FROGS 287 faces of the thighs and on the throat, but in approximately half of the specimens the throat lacks dark spots. In preserved specimens, the dorsal ground color varies from tan to gray or pale reddish brown; the dorsal markings are dark brown or dark gray. The venter is creamy white with brownish black spots. The anterior and pos- terior surfaces of the thighs are yellowish tan to grayish brown. Tadpoles: The sizes and proportions of tadpoles from Cinchona, Alajuela Province, Costa Rica are given in table 32. A typical tadpole in developmental stage 36 from the south fork of the Rio Las Vueltas, Heredia Province, Costa Rica, has a body length of 12.9 mm. and a total length of 39.7 mm. The body is slightly wider than deep. In dorsal profile the snout is broadly truncate; in lateral profile it is rounded. The nostrils are small, situated dorsolaterally, directed anteriorly, and are at a point about one-fourth the dis- tance from the eyes to the tip of the snout. The eyes are moderately small and directed dorsolaterally. The spiracle is sinistral and is situated about equidistant from the eye to the posteroventral edge of the body. The anal tube is short and median. The caudal muscu- lature is heavy and terminates near the tip of the caudal fin, which is bluntly rounded ter- minally. At mid-length of the tail the muscu- lature is about as deep as either the dorsal or ventral fins; the dorsal fin barelv extends onto the body (fig. 128B). The mouth is large and ventral; when it is fully opened it is visible anteriorly and lat- erally from above. The lips are folded later- ally. The lips are completely bordered by- three rows of moderately large peg-like pa- pillae; one or two rows of small papillae are also present on the edge of the lower lip. A few large papillae are present laterally in the fold of the lip. The upper beak is bow-shaped with long, slender, turned lateral processes. The lower beak is moderately robust and V- shaped; both beaks bear fine serrations. There are two upper and three lower rows of teeth; usually all rows are complete. The upper rows are equal in length and only slightly longer than the lower rows (fig. 129B). The body is dull brown with golden flecks, especially laterally. The caudal musculature is creamy tan with dark brown blotches dor- sally and brown or black flecks laterally. The caudal fins are transparent, except for scat- tered brown flecks. The iris is greenish bronze. In preservative, the body is dark brown; the caudal musculature is creamy white with brown flecks laterally and ventrally and brown markings dorsally. The dorsal markings tend to form broad transverse bars, separated by creamy white interspaces. The tadpoles described here agree with the description of the species given bv Starrett (1960a). Mating Call: The call of Hyla rivularis consists of a series of short, high-pitched, cricket-like notes. Each note contains three TABLE 32 Sizes and Proportions of Tadpoles of Hyla rivularis from Cinchona, Alajuela Province, Costa Rica. ( Means Are Given in Parentheses; Each Sample Contains Ten Specimens. ) Developmental Stage Body Length Tail Length Total Length Body/Tail 25 _. 5.7-10.6 (9.2) 28 10.8-12.0 (11.5) 31 11.0-12.9 (12.0) 37 12.2-13.2 (12.7) 41 13.0-14.8 (14.0) 11.1-20.5 16.8-31.0 0.49-0.54 (18.0) (27.3) (0.511) 21.0-23.8 31.8-35.8 0.47-0.52 (22.6) (34.1) (0.508) 21.5-26.1 32.5-38.9 0.46-0.51 (24.5) (36.5) (0.489) 26.0-28.1 38.8-40.7 0.44-0.49 (26.9) (39.6) (0.472) 26.0-28.5 39.0-43.3 0.49-0.53 (27.4) (41.3) (0.510) 288 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 pulses; the notes have a dominant frequency of about 2420 cycles per second. Each call group consists of 12 to 137 notes and has a duration of five to 66 seconds; call groups are repeated at intervals of about 10 to 70 seconds (pi. 19, fig. 3; table 31). Natural History: Hyla rivularis lives in cloud forests and breeds in clear, swift moun- tain streams. Males have been heard calling nearly every month of the year; probably due to equable climatic conditions in the cloud forests, this species breeds throughout the year. This suggestion is enhanced by the evi- dence of finding tadpoles in various stages of development throughout most of the year. Males call from herbs and low bushes at the edge of, or overhanging, fast-moving water. Usually the calling frogs are well hidden in the foliage; it is infrequent that a calling male is observed on a conspicuous perch. The tadpoles are usually found in pools in the rocky streams. The tadpoles adhere to the top and sides of large rocks in the pool. When the tadpoles are disturbed, they either move a short distance over the surface of the rock or seek refuge under rocks at the bottom of the pool. Three recently metamorphosed young from Chinchona, Alajuela Province, Costa Rica, have snout-vent lengths of 13.8, 14.8, and 15.0 mm. These small specimens were pale tan above and lacked dorsal dark markings, al- though one individual had numerous green flecks on the back. The venter was immacu- late yellow. Remarks: This species is abundant in the 11° 85° 83° \ ' ^"n^^. i *\ ^"\ I - 11° ^^ ..t " \ — "^° s * • • • • • I- i i 9° - oj -• 9° 0 50 100 \ \ i. ( \ ' / j" v\ i ^ C&r- KILOMETERS i 85° 83° Fig. 131. Distribution of Hyla rivularis. 1970 DUELLMAN: HYLID FROGS 289 high mountains of Costa Rica and western Panama; along mountain streams in these mountains, Hyla rivuhris occurs sympatrically with Hyla pictipes at higher elevations and Hyla tica and uranochroa at lower elevations. At elevations below 1500 meters, Hyla rivu- laris apparently is replaced by Hyla debilis. Etymology: The trivial name is Latin, rivularis, meaning "of a stream." The name was applied in reference to the stream-side habitat of this small frog. Distribution: Hyla rivularis inhabits cloud forests at elevations of 1280 and 2840 meters on both the Atlantic and Pacific slopes of the Cordillera Central, Costa Rica, and the Cor- dillera Talamanca in Costa Rica, and western Panama (fig. 131). See Appendix 1 for the locality records of the 303 specimens examined. Hyla debilis Taylor Hyla debilis Taylor, 1952c, p. 880 [holotype, K.U. No. 28184 from Isla Bonita, Heredia Province, Costa Rica; Richard C. Taylor and Edward H. Taylor collec- tors]. Diagnosis: This small species has an olive- green dorsum with small black flecks and a uniformly white belly; the flanks are white with small brown flecks. The thighs are olive- green dorsally and yellow posteriorly. A nar- row dark brown canthal stripe is bordered above by a bronzy tan stripe. A narrow white labial stripe usually is interrupted and ex- panded to form a spot below the eye. This species can be distinguished from xanthosticta by having yellow thighs and white flanks, in- stead of having both dark brown with yellow spots. Furthermore, xanthosticta has narrow white stripes on the forearm and tarsus and above the anus, and a continuous labial stripe. Superficially, Hyla debilis resembles Hyla ru- fioculis and uranochroa, both of which differ from debilis by having a white lateral stripe, white anal stripe, and red eye. The only other Middle American hylid that could be confused with debilis is Ptychohyla schmidtorum cham- ulae. That species has dull yellow thighs, a broad labial stripe which is continuous across the base of the arm to a stripe on the flank, and ventrolateral glands in breeding males. Description: Males of this small species attain a maximum snout-vent length of 29.5 mm., and females reach 31.6 mm. In a sample of nine males from an elevation of 1450 meters on the north slope of Cerro Pando, Rocas del Toro Province, Panama, the snout-vent length is 26.1 to 29.5 (mean, 27.5) mm.; the ratio of tibia length to snout-vent length is 0.461 to 0.515 (mean, 0.490); the ratio of foot length to snout-vent length is 0.390 to 0.462 (mean, 0.426 ) ; the ratio of head length to snout-vent length is 0.295 to 0.323 (mean, 0.310); the ratio of head width to snout-vent length is 0.284 to 0.316 (mean, 0.303), and the ratio of the diameter of the tympanum to that of the eye is 0.452 to 0.593 (mean, 0.534). Five females from the same locality have snout- vent lengths of 26.8 to 31.6 (mean, 29.9) mm. The females do not differ from the males in any of the proportions. Eleven males from Tapanti, Cartago Province, Costa Rica have snout-vent lengths of 24.9 to 26.8 ( mean, 25.8) mm.; a single specimen from that locality has a snout-vent length of 28.3 mm. Although the Costa Rican specimens are slightly smaller than those from Panama, there are no signifi- cant differences in the proportions. The head is as wide as the body; the top of the head is flat or slightly convex. In dorsal profile the snout is acutely rounded; in lateral profile it is rounded above and inclined pos- eroventrally to the lips. The snout is mod- erately long; the nostrils arc barely protuber- ant and are situated at a point about four- fifths of the distance from the eyes to the tip of the snout. The canthus is angular; the loreal region is noticeably concave, and the lips are moderately thick and barely flared. A moderately heavy dermal fold extends pos- teriorly from the posterior corner of the eye and curves along the upper edge of the tym- panum and thence downward to the anterior edge of the insertion of the arm. The fold covers the upper edge of the tympanum, which otherwise is distinct. The tympanum is situated posterior, and slightly ventral to the eye and is separated from the eye by a dis- tance nearly equal to the diameter of the tympanum. The arm is moderately short and robust. An abbreviated axillary membrane is present. A row of low tubercles forms a dermal ridge along the ventrolateral edge of the forearm; a distinct transverse dermal fold is present on 290 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 the wrist. The fingers are relatively short and broad and bear relatively small discs; the disc on the third finger is about two-thirds the diameter of the tympanum. The subarticular tubercles are moderately large and round; the distal tubercle beneath the fourth finger is usually bifid; the distal one on the third finger is bifid in about one-third of the specimens. The supernumerary tubercles are small and low. A bifid or tripartite palmar tubercle is weakly defined. The prepollex is moderately enlarged and in breeding males bear a horny nuptial excrescence composed of many small spinules. The hands are about one-third webbed ( fig. 126C ) . The webbing is vestigial between the first and second fingers, extends from the base of the penultimate phalanx of the first to the base of the antepenultimate phalanx of the second, and from the middle of the antepenultimate phalanx of the second to the distal end of the antepenultimate pha- lanx of the third finger. The hind limbs are moderately short and robust; the adpressed heels overlap by about one-fifth the length of the shank. The tibiotarsal articulation extends to the posterior corner of the eye. The tarsal fold is absent. A row of low tubercles forms an indistinct dermal fold on the outer edge of the tarsus. The inner metatarsal tubercle is low, flat, ovoid, and barely visible from above; the outer metatarsal tubercle is a mi- nute cone-shaped bump. The toes are mod- erately long and slender and bear discs that are about the same size as those on the fin- gers. The subarticular tubercles are moderate- ly small, round, and conical. The subarticular tubercles are usually absent on the distal seg- ments of the toes and only weakly defined, if at all, on the proximal segments. The toes are about two-thirds webbed (fig. 127C). The webbing extends from the base of the penulti- mate phalanx of the first toe to the base of the penultimate phalanx of the second toe, from the middle of the penultimate phalanx of the second to the distal end of the antepenulti- mate phalanx of the third, from the base of the penultimate phalanx of the third to the middle of the antepenultimate phalanx of the fourth and onto the distal end of the penulti- mate phalanx of the fifth toe. A narrow dermal fringe extends along the outer edge of the fifth toe. The anal opening is directed posteroven- trally at the level of the middle of the thighs. A short anal sheath is present; the area below the anal opening is covered with large tuber- cles. The skin on the belly and the proximal parts of the posteroventral surfaces of the thighs is strongly granular. Elsewhere the skin is nearly smooth. A weak thoracic fold is pres- ent. The tongue is broadly cordiform, barely notched posteriorly and only slightly free be- hind. The dentigerous processes of the pre- vomers are small, elliptical structures lying between the posterior borders of the ovoid choanae. In males, two or three teeth are present on each prevomerine ridge; all females have three teeth on the ridge. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately dis- tensible. The general coloration of Hyla debilis is brown with green and darker brown flecks on the dorsum (pi. 53, fig. 3). Usually the side of the head and flanks are dull green, and the dorsal surfaces of the limbs, third and fourth fingers, and fourth and fifth toes are brown. The groin, anterior and posterior surfaces of thighs, ventral surfaces of hind limbs, and dorsal surfaces of the first three toes are deep yellow. The ventral surfaces of the forearm and dorsal surfaces of the first two fingers lack pigment. One or more labial spots, the throat, and belly are white. The anal tubercles, the stripe on the outer edge of the tarsus and fifth toe, and the stripe on the outer edge of the forearm and the fourth finger are creamy white. The iris is dull coppery bronze. The palpebrum is clear above but faintly reticu- lated with green below. In preservative, the dorsum is dull gray or brown, with or without small darker flecks. The anterior and posterior surfaces of the thighs and groin are creamy tan. The venter is creamy white. All specimens have a distinct white spot on the lip below the eye. Another, slightly smaller spot, is present on the upper lip mid- way between the eye and the nostril; another spot is usually present on the tip of the upper lip. In many specimens, this is confluent with the lateral spot. In most specimens there is a definite line of demarcation between the dark 1970 DUELLMAN: HYLID FROGS 291 dorsal pigment and the pale color on the pos- terior surfaces of the thighs, but in some indi- viduals the edge of the dorsal dark color is scalloped, interrupted dorsally by extensions of the yellow on the posterior surfaces of the thighs, or scattered as discreet brown spots on the posterior surfaces of the thighs. Some males when calling at night were pale brown above with metallic green flecks, and the chin and belly were pale lemon yellow. One indi- vidual was uniform olive-tan above. Tadpoles: In a series of ten tadpoles in developmental stage 25 from an elevation of 1450 meters on the north slope of Cerro Pan- do, Bocas del Toro Province, Panama, the body length is 6.3 to 8.0 (mean, 7.2) mm.; the tail length is 12.5 to 15.4 (mean, 14.0) mm., and the total length is 19.0 to 23.4 (mean, 21.3) mm. Ten tadpoles in developmental stage 28 from the same locality have body lengths of 9.4 to 13.7 (mean, 11.6) mm., tail lengths of 17.1 to 29.3 (mean, 23.3) mm., and total lengths of 26.5 to 43.0 (mean, 34.9) mm. A large tadpole in developmental stage 28 has a body length of 13.7 mm. and a total length of 43.0 mm. The body is slightly de- pressed, barely wider than deep. In dorsal profile the snout is bluntly rounded; in lateral profile it is more acutely rounded. The eyes are small, widely separated, and directed dor- solaterally. The nostrils are situated dorso- laterally at a point about equidistant between the eyes and the tip of the snout. The spiracle is sinistral and situated on the midline at a point midway between the eye and the pos- terior edge of the body. The anal tube is short and dextral. The tail is long, low, and blunt terminally. The caudal musculature is robust; at midlength of the tail, the depth of the musculature is equal to the depth of either fin. The dorsal fin does not extend onto the body (fig. 128C). The mouth is large and ventral in position. The lips are deeply folded laterally. Two or three rows of moderately large, blunt papillae border the lips; numerous papillae are present in the lateral fold. The beaks are robust; the upper beak forms a broad arch, and the lower beak is broadly V-shaped. Both beaks bear moderately long, fine serrations. There are two upper and three lower rows of teeth. In all tadpoles, the second upper row is inter- rupted medially, whereas in approximately half of the specimens the first is interrupted and in others it is complete. The second up- per row is slightly shorter than the first; the three lower rows are complete, approximately equal in length, and only slightly shorter than the second upper row (fig. 129C). Dorsally the body is mottled dark brown and tan; this coloration extends onto the side of the body where some metallic gold flecking is present. The venter is dark brown except midventrally, where it is gray. The caudal musculature is tan with small brownish gray flecks and dark brown spots. The caudal fins are unpigmented except for a few brown spots and posteriorly a suffusion of gray flecks. The iris is a golden color with gray peripherally. In preservative, the anterior part of the body- is dark brown; posteriorly the body is tan. The caudal musculature is creamy white with dark brown spots, which tend to form a longi- tudinal line along the dorsolateral edge of the caudal musculature. Mating Call: The mating call of Hyla debilis consists of a series of extremely weak "cricket-like" chirps. There are five to seven notes in each call group which has a duration of 0.10 to 0.16 of a second. There is only a single pulse per call, and the dominant fre- quency is at about 5235 cycles per second (table 31; pi. 21, fig. 2). Natural History: The limited informa- tion on Hyla debilis indicates that this species is an inhabitant of lower reaches of cloud for- ests, where it breeds in mountain streams. Taylor (1952c) reported that the type and paratype were collected at Isla Bonita, Heredia Province, Costa Rica, on August 1, 1947. Norman Scott and J. M. Savage ob- tained this species at Tapanti, Cartago Prov- ince, Costa Rica, on September 27 and De- cember 19, 1963. I collected Hyla debilis on several dates in May on the north slope of Cerro Pando, Bocas del Toro Province, Pana- ma. Despite the intensive field work by sev- eral herpetologists in the area around Isla Bonita and at Tapanti, the species has not been found again at either of these localities. Since there are several stream-breeding frogs at these localities it is conceivable that the species has been present there at the time 292 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 when the collectors visited, but because of the weak voice it is not easily found. On the north slope of Cerro Pando, males of Hyla debilis called from concealed sites within dense vegetation at the edge of, or overhanging, small mountain streams. Fe- males were found on bushes near the streams, except one which was sleeping on the leaf of a tree approximately 300 meters from the nearest stream. The tadpoles were found adhering to the sides and tops of rocks in the bottom of the pool in a small, rocky, gravel-bottomed stream. Two tadpoles were raised to metamorphosis at which time they had snout-vent lengths of 12.7 and 13.1 mm. Another juvenile having a snout-vent length of 17.8 mm. was found on low vegetation near a stream. The juveniles were colored like the adults, except that a creamy canthal stripe was apparent, and the loreal region was pale green. Furthermore, one of the juveniles had a distinct olive tint to the brown dorsal coloration. Remarks: Hijla debilis seems to replace Hyla rivularis, which is known from higher elevations. The two frogs are extremely simi- lar in their mating calls, general morphology, and breeding behavior. Likewise, the tadpoles occupy the same microhabitat within the stream. A specimen (U.M.M.Z. No. 69496) from Boquete, Chiriqui Province, Panama, is tenta- tively assigned to this species. Most of the pigment is faded, and identification can not be certain. Etymology: The specific name is Latin, debilis, meaning weak, in reference to the voice of this species. Distribution: Hyla debilis is known from cloud forests from elevations of 910 to 1450 meters on the Caribbean slopes of the Cordil- lera Central in Costa Rica and the Cordillera Talamanca in Costa Rica and western Pan- ama. If the specimen from Boquete is cor- rectly identified, this specimen represents the only record for the species on the Pacific slope (fig. 132). See Appendix 1 for the locality records of the 40 specimens examined. Hyla xanthosticta Duellman Hyla xanthosticta Duellman, 1968a, p. 562 [holo- type, K.U. No. 10.3772 from the south fork of the Rio Las Vueltas, on the south slope of Volcan Barha, near the northwest base of Cerro Chonpipe, Heredia Province, Costa Rica, 2100 meters; John D. Lynch collector]. Diagnosis: This member of the Hyla rivu- laris group has a uniform green dorsum and unmarked throat and belly; the flanks and thighs are dark brown with large bright yel- low spots (white in preservative). A broad bronze-tan canthal stripe is present. This com- bination of characters distinguishes xantho- sticta from all known Middle American hylids. Hyla debilis possesses the canthal stripe but has creamy white flanks and yellow posterior surfaces of the thighs. Furthermore, xantho- sticta has a narrow continuous white labial stripe; the labial stripe in debilis usually is interrupted and expanded below the eye. Fe- male Hyla pictipes have small yellow spots on dark brown or black flanks and thighs, but lack the white stripes on the lips, forearms, tarsi, and above the anus that are present in xanthosticta. Furthermore, pictipes has a spotted venter. The Mexican Hyla euphor- biacea has brown thighs with small yellow spots, but in that species the dorsum is green with brown markings and broad brown can- thai and postorbital stripes are present. Description: This species is known from a single specimen, a female, having a snout- vent length of 29.3 mm.; the ratio of the tibia length to the snout-vent length is 0.553; the ratio of foot length to snout-vent length is 0.481; the ratio of head length to snout-vent length is 0.341; the ratio of head width to snout-vent length is 0.352, and the ratio of the diameter of the tympanum to that of the eye is 0.500. The head is as wide as the body; the top of the head is convex. In dorsal profile the snout is narrow and truncate; in lateral profile it is truncate, slightly inclined posteroven- trally. The snout is moderately long. The nostrils are slightly protuberant, directed lat- erally, and situated at about four-fifths the distance from the eye to the tip of the snout. The canthus is angular; the loreal region is barely concave, and the lips are thick and barely flared. A moderately heavy dermal fold extends from the posterior corner of the eye and curves above the tympanum downward to the anterior edge of the insertion of the arm. 1970 DUELLMAN: HYLID FROGS 293 11° 85° 83° e£v "^ r\ I - 11° > \ V r^-^v • \ V* \. \ ^ * ^s^*— • 9° - OS • \ / ( ^ ( • 9° 0 50 100 ^1 \ ^ V \ y ( J "-v r ^^u KILOMETERS . ..i 85° 83° Fig. 132. Distribution of Hy/a debilis. The fold obscures the upper edge of the tym- panum, which otherwise is barely distinct. The tympanum is situated posteroventrally to the eye and is separated from the eye by a distance equal to twice the diameter of the tympanum. The arms are moderately long and slender; there is no axillary membrane. A thin, scal- loped dermal fold is present on the ventrolat- eral edge of the forearm; a thin transverse der- mal fold is present on the wrist. The fingers are long and rather slender. The discs are moderately large; that on the third finger is equal to the diameter of the tympanum. The subarticular tubercles are large; the distal tu- bercle on the third finger is broad and flat; the distal tubercle on the fourth finger is strongly bifid. Supernumerary tubercles are large, round, closely spaced, and irregular on the proximal segments of the digits. The pre- pollex is moderately enlarged. The fingers are about one-fourth webbed (fig. 126D). The web is lacking between the first and second fingers and vestigial between the second and third. The web extends from the middle of the antepenultimate phalanx of the third to the base of the penultimate phalanx of the fourth finger. The hind limbs are moderately short and slender; the heels overlap by about one-third the length of the shank. The tibio- tarsal articulation extends to the anterior corner of the eye. A thin transverse dermal fold is present on the heel and a scalloped dermal fold extends along the outer edge of 294 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 the tarsus. The tarsal fold is lacking. The inner metatarsal tubercle is large, flat, ellip- tical, and visible from above. The outer meta- tarsal tubercle is small and subcorneal. The toes are long and slender; the discs are slightly smaller than those on the fingers. The sub- articular tubercles are large, round, and sub- conical; the supernumerary tubercles are few in number and are scattered on the proximal segments of the digits. The toes are about two-thirds webbed ( fig. 127D ) . The web ex- tends from the middle of the penultimate pha- lanx of the first toe to the middle of the pen- ultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the base of the penultimate phalanx of the third, from the distal end of the penultimate phalanx of the third to the middle of the ante- penultimate phalanx of the fourth and on to the middle of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally at the midlevel of the thighs; it is bor- dered below by large tubercles. There is no anal sheath. The skin is smooth on the dor- sum except for small scattered tubercles; the skin on the belly and posteroventral surfaces of the thighs is granular. The tongue is round, emarginate, and barely free behind. There are five prevomerine teeth on each side, situ- ated on large ovoid elevations at a level of the posterior edges of the small, round choanae. The general coloration of Hyla xantho- sticta is green with brown flanks and thighs with large yellow spots (pi. 53, fig. 4). The green dorsum is palest on the sides of the head. The dorsal surfaces of the thighs are tan. The flanks, anterior and posterior sur- faces of the thighs, and the inner surfaces of the tarsi are brown with bright yellow spots. A broad bronze-tan (reddish copper at night) canthal stripe is present. The throat and belly are pale yellow; the ventral surfaces of the limbs are dull, dark yellow. A large, bright yellow spot is present on the anteroventral sur- face of each thigh. Bright yellow tubercles are present on the median part of the thighs. The anal area is dark brown with a white stripe above and a yellow stripe below. There is a white stripe on the outer edge of the forearm, one on the outer edge of the tarsus, and another on the edge of the upper lip. The iris is a golden color with fine black re- ticulations and faint reddish suffusion medi- ally. The palpebral membrane is clear. In preservative, the dorsum is dark pur- plish brown and brown on the limbs. The first three fingers and first three toes are creamy yellow and the other digits are brown. The flanks are dark brown with white spots; the anterior and posterior surfaces of the thighs and inner surfaces are brown with eream-colored spots. The stripes on the edge of the upper lip, ventrolateral edge of the forearm, outer edge of the tarsus, and above the anus are white. The chin and throat are white, and the belly and ventral surfaces of the limbs are creamy white. Tadpoles: The tadpoles of this species have not been collected. Presumably, they develop in mountain streams. Mating Call: The call of Hyla xantho- sticta is unknown. Natural History: The only known speci- man of Hyla xanthosticta was perched at night on a leaf about 1 meter above the ground. The frog was found in humid upper montane forest characterized by large oaks supporting many bromeliads and heavy growths of mosses. Remarks: On the basis of external morpho- logical characters and partial dissection of the skull, it is possible to ally Hyla xanthosticta with the Hyla rivularis group. At the type locality on Volcan Barba, Heredia Province, Costa Rica, Hyla xanthosticta occurs sympat- rically with Hyla rivularis and Hyla pictipes. Etymology: The specific name is de- rived from the Greek xanthos meaning yellow and the Greek stiktos meaning spotted, and alludes to the diagnostic yellow spots on the flanks and thighs. Distribution: Hyla xanthosticta is known only from an elevation of 2100 meters on the south slope of Volcan Barba, Heredia Prov- ince, Costa Rica (fig. 130). See Appendix 1 for the locality record for the one specimen examined. The Hyla pictipes Group Definition : The one species in this group is a moderately small, stream-breeding frog; males attain a maximum snout-vent length of 39 mm. and females, 45 mm. The dorsum is 1970 DUELLMAN: HYLID FROGS 295 green or mottled dull green and black. The fingers are about one-fourth webbed, and the toes are about three-fourths webbed. Dermal appendages and fringes are lacking. Males have a single, median, subgular vocal sac and a horny nuptial excrescence on the pollex. The cranial elements are moderately ossified; a medium-sized frontoparietal fontanelle is pres- ent. The sphenethmoid is rather short; the nasals are in partial bony contact with the sphenethmoid and lack maxillary processes. The quadratojugal is absent. The pterygoid lacks a bony connection with the prootic. The anterior arm of the squamosal is short and blunt. Prevomerine teeth are present (fig. 133). The tadpoles have a long terminally rounded tail and a large, ventral mouth with two upper and three lower rows of teeth. The mating call consists of a single, pulsed, low- pitched note. The haploid number of chromo- somes is 12. Composition': Hijla pictipes is the sole ' W *W \fN -jjw rjrrTT Fig. 133. Dorsal (A) and lateral (B) views of the skull of Hijla pictipes, K.U. No. 68314. x 5. member of the group; 143 preserved speci- mens, five skeletons, and nine lots of tadpoles have been examined. Comments: Starrett (1966) included H yla debilis, rivularis, and pictipes in the Hyla pic- tipes group. The reasons for segregating pic- tipes from the other species are presented in the account of the Hijla rivularis group. Hyla pictipes Cope Hyla punctariola pictipes Cope, 1876, p. 106 [syn- types, U.S.N.M. Nos. 30631 and 30652 from Pico Blanco, Limon Province, Costa Rica; William M. Gabb collector]. Hyla punctariola moesta Cope, 1876, p. 106 [holo- type, U.S.N.M. No. 20660 from Pico Blanco, Limon Province, Costa Rica; William M. Gabb collector]. Hyla punctariola monticola Cope, 1876, p. 106 [holotype, U.S.N.M. No. 30661 from Pico Blanco, Limon Province, Costa Rica; William M. Gabb collec- tor], Hyla punctariola: Boulenger, lS82a, p. 401 [part]. Hyla moesta: Taylor, 1952c, p. 855. Hyla monticola: Taylor, 1952c, p. 855. Hyla pictipes: Taylor, 1952c, p. 878. Starrett, 1966, p. 17 [synonymized Hyla punctariola moesta Cope, 1876, and Hyla punctariola monticola Cope, 1876, with Hyla pictipes]. Diagnosis: Hyla pictipes differs from all other Middle American hylids by having a mottled green and black dorsum in males and uniform green dorsum in females, dark brown or black flanks and posterior surfaces of the thighs with small creamy white or yellow spots, an angular snout in lateral profile, the fingers only one-third webbed, and dark spots on the venter. Hyla tica is similar in general appearance, but has a rounded snout, and a larger tympanum; the average ratio of the diameter of the tympanum to that of the eye in pictipes is 0.377 and in tica, 0.517. Hyla xanthosticta superficially resembles females of pictipes, but the former has larger yellow spots on the flanks and thighs and has a bronze-tan canthal stripe and white stripes on the outer edges of the forearms and tarsi, on the edge of the upper lip, and above the anus; these stripes are usually absent in pictipes ( labial stripe present in some specimens). Description: Males of this moderate-sized species attain a maximum snout-vent length of 39.0 mm., and females reach 45.1 mm. In a sample of 25 males from the Rio Poasito on Volean Poas, Alajuela Province, Costa Rica, 296 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 the snout-vent length is 31.8 to 37.6 (mean, 34.8) mm.; the ratio of tibia length to snout- vent length is 0.478 to 0.540 (mean, 0.505); the ratio of foot length to snout-vent length is 0.421 to 0.484 (mean, 0.457); the ratio of head length to snout-vent length is 0.298 to 0.345 (mean, 0.315); the ratio of head width to snout- vent length is 0.306 to 0.355 (mean, 0.326), and the ratio of the diameter of the tympanum to that of the eye is 0.289 to 0.514 (mean, 0.377). Six females from the same lo- cality have snout-vent lengths of 40.9 to 44.6 (mean, 42.7) mm. They do not differ signifi- cantly from the males in proportions, except that the tympanum is slightly larger; the ratio of the diameter of the tympanum to that of the eye is 0.295 to 0.487 (mean, 0.405). The body is robust; the head is not quite as wide as the body. The top of the head is slightly convex. In dorsal profile, the snout is acutely rounded; in lateral profile, it is rounded above and slightly inclined posteroventrally. The snout is moderately short; the nostrils are slightly protuberant and are situated ap- proximately two-thirds the distance from the eyes to the tip of the snout. The canthus is rounded, but distinct; the loreal region is nearly flat and continuous with the thick and barely flared lips. A moderately heavy der- mal fold extends posteriorly from the posterior corner of the eye and curves above the tym- panum to a point above the insertion of the arm. The fold covers the upper edge of the tympanum, which otherwise is barely distinct beneath the skin. The tympanum is located posteroventral to the eye and is separated from the eye by a distance equal to about half again the diameter of the tympanum. The arm is moderately long and slender; there is no axillary membrane. A row of low tubercles is present along the ventrolateral edge of the forearm, but these do not form a dermal ridge. A heavy transverse dermal fold is present on the wrist. The fingers are rela- tively long, but robust, and bear large discs; the disc on the third finger is half again as broad as the diameter of the tympanum. The subarticular tubercles are large and subcorn- eal; the distal tubercle on the fourth finger is divided or bifid in all specimens. The super- numerary tubercles are moderately large, dis- tinct, and subcorneal. They are arranged in a single row on the proximal segments on the second and third fingers and in one or two rows on the proximal segment of the fourth finger. The outer palmar tubercle is low, flat, and indistinct in most specimens; in many individuals it is tripartite. The prepollex is greatly enlarged, and in breeding males it bears a horny nuptial excrescence. The hands are about one-fourth webbed (fig. 134A). The webbing is vestigial between the first and second fingers; it extends from the base of the penultimate phalanx of the second to the base of the antepenultimate phalanx of the third finger and from the middle of the antepenulti- mate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are moderately short and robust; the adpressed heels overlap by about one-fourth the length of the shank. The tibiotarsal articulation extends to the middle of the eye. There is no tarsal fold. The inner metatarsal tubercle is low, flat, elliptical, and visible from above. The outer metatarsal tu- bercle is small and subcorneal. The toes are moderately long and slender and bear discs that are only slightly smaller than those on the hands. The subarticular tubercles are moderately large and subcorneal. The super- numerary tubercles are small, conical, and present only on the proximal segments of the toes. The toes are about three-fourths webbed ( fig. 134B ) . The webbing extends from the base of the disc of the first toe to the base of the penultimate phalanx of the second, from the base of the disc of the second to the mid- dle of the antepenultimate phalanx of the third, from the middle of the penultimate pha- lanx of the third to the distal end of the ante- penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. A thin dermal fringe extends from the inner meta- tarsal tubercle to the base of the disc of the first toe; another dermal fringe is present on the lateral edge of the fifth toe. The anal opening is directed posteroven- trally at the midlevel of the thighs. The open- ing is covered by a short, thick anal sheath. The skin on the dorsal surfaces of the body and limbs and on the ventral surfaces of the shanks is smooth; that on the ventral surfaces of the forelimbs and thighs and on the throat and belly is granular. The tongue is ovoid, 1970 DUELLMAN: HYLID FROGS 297 Fig. piciipes, 134. K.U. Hand (A) No. 103694. and foot X 5. (B) of Hyla nearly as broad as long. In some specimens, it is emarginate, but in most it is shallow]) notched either anteriorly, posteriorly, or both. The dentigerous processes of the prevomers are moderately large and elliptical; they are situated between the posterior borders of the relatively ovoid choanae. Males have three to six teeth on each prevomerine process and have a total of six to 12 (mean, 9.0) prevo- merine teeth. Females have five to eight teeth on each process and a total of 11 to 15 (mean, 12.7) prevomerine teeth. The vocal slits ex- tend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and barely disten- sible. The general coloration of Hyla pictipes is dull green with dark brown or black mottling dorsally in males or fairly uniform green dor- sally in females (pi. 53, figs. 5 and 6). The dorsal ground color in males varies from pale green to dull olive-green or olive-tan with darker olive-brown, dark brown, or black mot- tling. In most individuals, the mottling covers a greater part of the dorsum than does the ground color. The upper surfaces of the limbs are colored like the body; there are no distinct bars on the limbs. The loreal region is usually a dull pale green. The anterior and posterior surfaces of the thighs and the flanks are dark brown with small, bright yellow spots. The ventral surfaces of the hands and feet are dark brown, and the ventral surfaces of the legs are grayish brown or dull yellowish tan. The belly is dull yellow, heavily suffused with brown or gray; the throat and chest are a dusty cream-color mottled with brown. In females, the dorsum is uniform pale olive-green; the sides of the head and upper surfaces of the limbs are colored like the body. The anterior and posterior surfaces of the thighs are brown with pale yellow spots; the flanks are dark brown with creamy yellow spots. The ventral surfaces of the hind limbs are dull yellow. The ventral surfaces of the forelimbs are dusty yellow, and ventral surfaces of the hands and feet are dull yellow with a suffusion of brown. The belly is bright yellow, and the throat is creamy yellow. In some individuals a narrow, faint white line is present on the upper lip. The iris in both sexes varies from a greenish bronze to a golden bronze or dull copper color. 298 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Some individuals when found by day were pale yellowish tan above; later these changed to green with dark mottling. Most of the specimens that have been examined in life came from Volcan Poas or Volcan Barba. Few differences were noted in the coloration be- tween samples from these two localities. Per- haps the most noticeable difference is that in males from Volcan Barba the belly seems to be more heavily suffused with dark pigment than in those specimens from Volcan Poas. Furthermore, the greenish bronze color of the iris has been noted only in specimens from Volcan Barba. In preservative the dorsal coloration of males is dull brown with darker brown mark- ings; in females the dorsum is uniform tan or dull brown. In specimens of both sexes, the anterior and posterior surfaces of the thighs and the flanks are dark brown with creamy tan spots. The venter is dull yellowish tan in both sexes, suffused with brown or gray in males. In some females distinct brown spots are present; these were not noticed in living individuals. Tadpoles: The sizes and proportions of tadpoles of Hyla pictipes in relation to the developmental stages are given in table 33. A typical tadpole in developmental stage 38 has a body length of 15.5 mm. and a total length of 42.4 mm. The body is depressed; it is half again as wide as deep. The top of the head is flat and inclined anteriorly from a point above the eyes. The posterior part of the venter is rounded, whereas the anterior part is flat. In dorsal profile the body is bluntly rounded anteriorly and posteriorly; in lateral profile the snout slopes gradually and is acute- ly rounded. The eyes are small; they are situated dorsally and directed dorsolaterally. The nostrils are about one-fourth the distance from the eyes to the tip of the snout. The spiracle is sinistral and situated about midway between the eye and the posteroventral edge of the body. The anal tube is short and me- dian. The caudal musculature is robust and extends nearly to the tip of the tail. At mid- length of the tail the depth of the musculature is greater than that of either fin. The dorsal fin does not extend onto the body, and the caudal fin is bluntlv rounded terminally (fig. 135). The mouth is exceedingly large and ventral in position; the lateral edges of the lips are visible from above. A deep lateral fold is present. A single row of small papillae com- pletely borders the mouth. Lying medial to these are two rows of small papillae on the anterior lip and four to six rows on the pos- terior lip; there are no papillae in the lateral folds. The beaks are rather weak and bear minute serrations. The upper beak is strongly bow-shaped, whereas the lower beak is broad- ly V-shaped. There are two upper and three lower rows of teeth; all are complete. The upper rows are about equal in length; the lower rows arc only slightly, if at all, shorter than the upper rows. The teeth are small and are situated on low, fleshy ridges (fig. 136). The body is black with golden lichenous markings. The tail musculature is tan and the fins are clear. The iris is black with gold flecks. In preservative, the body is dark brown, slightly paler anteriorly. The caudal muscu- lature is brown, and the caudal fins are trans- parent with faint brown flecks. The tadpoles all have two upper and three lower rows of teeth. The rows are approxi- mately equal in length in tadpoles in develop- mental stage 31 and later stages. In tadpoles in developmental stages 27 and 29, the second upper and first lower rows are noticeably shorter than the others. In one tadpole in developmental stage 25, the two upper and the first lower rows are short. Mating Call: The call of Hyla pictipes Fig. 135. Tadpole of Hyla pictipes, K.U. No. 68437. x 3. 1970 DUELLMAN: HYLID FROGS 299 TABLE 33 Sizes and Proportions, with Means in Parentheses, of Tadpoles of Hyla pictipes. Developmental Stage N Body Length Tail Length Total Length Body/Tail 25 1 27 __ 5 29 3 31 8 35 2 38 2 40 2 43 6 9.8 16.7 26.5 58.6 11.0-11.5 17.6-19.5 28.6-30.0 57.6-61.3 (11.2) (18.9) (29.4) (59.1) 11.5-12.2 20.0-25.0 31.5-37.2 51.3-53.1 (11.8) (22.4) (34.2) (52.6) 13.0-14.5 22.4-25.5 36.5-40.0 56.8-63.2 (13.9) (24.0) (38.0) (63.1) 15.1-15.3 26.9-27.4 42.0-42.5 55.8-56.1 (15.2) (27.2) (42.3) (56.0) 15.5-16.0 26.9-29.0 42.4-45.0 55.2-57.6 (15.8) (28.0) (42.7) (56.4) 17.0-17.6 27.0-28.6 44.0-46.2 61.5-62.9 (17.3) (27.8) (45.1) (62.2) 15.6-18.0 7.3-13.8 23.8-30.0 10.1-29.3 (16.8) (9.2) (26.5) (17.2) consists of a single, pulsed, low-pitched note, which is repeated at intervals of 20 seconds to several minutes. The duration of the note is 0.28 to 0.38 (mean, seven calls, 0.32) of a second. The pulse rate is 110 to 143 (mean, 123) pulses per second, and the dominant fre- quency varies from 2230 to 2750 ( mean, 2591 ) cycles per second ( pi. 23, fig. 1 ) . Natural History: Hyla pictipes inhabits high montane forests that receive abundant moisture throughout the year; the frogs are active year round and possibly breed through- out the year. However, calling males seem to be most abundant in March through May. Fig. 136. Mouth of tadpole of Hyla pictipes, K.U. No. 68437. x 8. The frogs are always found in close proximity to mountain streams. Males call from rocks in and along edges of streams and from the branches of low (usually no more than 1 meter above ground) vegetation. By day, the frogs take refuge beneath rocks at the edges of the streams. Mating activity is carried on at relatively low temperatures; males were call- ing when the air temperature was between 8 and 18 degrees centigrade. The tadpoles develop in cold mountain streams, where they cling to the tops or sides of large stones in the streams. When the tadpoles are disturbed, they swim against the strong current and adhere to another rock or take refuge beneath rocks at the bottom of the stream. At the Rio Poasito on Volcan Poas, Alajuela Province, Costa Rica, tadpoles of Hyla pictipes were found in the same stream with those of Hyla rivularis. The tadpoles of these two species are similarly adapted for a stream existence. No different ecological pref- erences of the tadpoles were observed. Two recently metamorphosed young were collected on April 17, 1961, at the Rio Poasito. These small individuals were found on low vegetation at the edge of a rocky stream at night. The frogs have snout-vent lengths of 20.1 and 20.8 mm. In life, the dorsum was pale greenish brown and the belly and feet were pale yellow. The flanks were brown and 300 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 white; the posterior surfaces of the thighs were yellowish brown with pale yellow spots. Three tadpoles collected at the Rio Poasito on May 7, 1961, were transformed in the laboratory. Up- on transformation, the frogs had snout-vent lengths of 16.0, 17.0, and 18.4 mm, In life, the dorsum was dull green with a faint brown- ish tinge middorsally. The hands, feet, and thighs were dark yellow. The venter was creamy yellow and the flanks were cream with brown spots. Remarks: Cope (1876) described and named three varieties of Hyla punctariola. Dunn (1940b) showed that punctariola is ac- tually a species of Eleutherodactylus. Starrett (1966) and Duellman (1966b) pointed out the rediscovery of Hyla pictipes and discussed the taxonomie status of the other two varieties ( moesta and monticola ) described by Cope. Etymology: The specific name is derived from the Latin pictilis meaning painted and the Latin pes meaning foot and alludes to the dark pigmentation on the feet. Distribution: Hyla pictipes is known from montane forests at elevations of 1900 and 2500 meters in the Cordillera Central of central Costa Rica and on the Pacific slopes of the Cordillera Talamanca in Costa Rica (fig. 137). See Appendix 1 for the locality records of the 157 specimens examined. Fig. 137. Distribution of Hi/la pictipes. 1970 DUELLMAN: HYLID FROGS 301 The Hyla uranochroa Group Definition: Members of this group are moderately small stream-breeding species; males attain a maximum snout-vent length of 36.8 mm. and females, 39.9 mm. The dorsum is pale green or olive or reddish brown with a white stripe on the edge of the lip and edges of the forearms and feet. The iris is red, and the palpebral membrane is clear or weakly flecked. The fingers are about one-fourth and the feet, two-thirds webbed. A weak tarsal fold is present, but an axillary membrane and dermal folds or appendages on the limbs are absent. Males have single, median, subgular vocal sacs and horny nuptial excrescences on the prepollices. The skull is only moderately ossified. A large frontoparietal fontanelle is present. The sphenethmoid is broad and short and does not extend anteriorly between the nasals, which are slender, widely separated medially, and not in contact with the sphen- ethmoid (fig. 138). The squamosal is in bony contact with the crista parotica, and the an- terior arm of the squamosal extends one-third (rufioculis) or one-half (uranochroa) of the Fig. 138. Dorsal (A) and lateral (B) views of the skull of Hyla uranochroa, K.U. No. 117433. X 5. distance to the maxillary. The quadratojugal is in contact with the maxillary in uranochroa and present only as a spur posteriorly in rufioculis. The medial ramus of the pterygoid is in bony contact with the prootic. The pre- vomcrs are poorly ossified but bear teeth. The tadpoles have long tails with low fins and large funnel-shaped ventral mouths. The mating call consists of a long series of well- modulated notes or a short rattling series of notes. The haploid number of chromosomes is 12. Composition: Two species (Hyla rufio- culis and uranochroa) comprise the group, which is endemic to the highlands of Costa Rica and western Panama. Of these, 546 pre- served frogs, 16 skeletons, and 28 lots of tad- poles have been examined. Comments: Savage (1968) included in the uranochroa group all of those species that I place in the rivularis, pictipes, and urano- chroa groups, plus Hyla legleri. Because of the presence of a red eye in the adult, Hyla legleri formerly has been associated with this group (Starrett, 1966; Savage, 1968). However, leg- leri differs from members of the Hyla urano- chroa group osteologically and has a distinctly different kind of tadpole; in these characters it closely resembles salvadorensis and accord- ingly is more properly associated with that species. Both species in the Hyla uranochroa group occur on the Caribbean and Pacific slopes of Costa Rica; the two species have different alti- tudinal ranges. In some areas, Hyla urano- chroa descends to elevations inhabited by ru- fioculis, so that the two occur sympatrically and even breed in the same streams at the same time. The differences in mating calls probably act to enhance reproductive isola- tion in sympatric populations. It is likely that the two species differentiated through altitu- dinal separation rather than one on the Carib- bean and the other on the Pacific slopes. Both the adults and tadpoles of the mem- bers of the Hyla uranochroa group bear a striking resemblance to Ptychohyla schmid- torum in northern Central America. The for- mer differs from Ptychohyla by having the nasals separated from, instead of broadly su- tured to, the sphenethmoid, by having tad- poles with two, instead of three, upper rows 302 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 of teeth, and by lacking ventrolateral glands in breeding males. These similarities seem to be the result of convergence rather than an indication of close relationship. Hyla uranochroa Cope Hyla uranochroa Cope, 1876, p. 103 [holotype, U.S.N.M. No. 20651 from near Sipurio, Limon Prov- ince, Costa Rica; William M. Gabb collector]. Brocchi, 1SS2, p. 38. Boulenger, 1882a, p. 377. Gunther, 1901 (1885-1902), p. 276. Taylor, 1952c, p. 834. Duellman, 1966, p. 276 [synonymized Hyla allcei Taylor with Hyla uranochroa]. Hyla alleei Taylor 1952c, p. 831 [holotype, R.C.T. No. 775 from Isla Bonita, Heredia Province, Costa Rica; Richard C. Taylor collector]. Diagnosis: This moderately small green Hyla with red eyes, truncate snout, little web- bing, and a white lateral stripe is readily dis- tinguished from its apparent closest relative, rufiocidis, by having a larger tympanum ( more than 50 per cent of the diameter of the eye in uranochroa and less than 50 per cent in rufioculis), longer snout, unpigmented plantar surfaces of the feet, and a straight white labial stripe (expanded below the eye in rufioculis). Hyla legleri and erythromma also have red eyes; the former has more webbing, a dark brown dorsum, and a dark throat in breeding males; the throat in uranochroa is yellow in life and white in preservative. Hyla erythrom- ma has mottled brown and white flanks, acute- ly rounded snout, and more webbing than does uranochroa. Description: Males of this moderately small species attain a maximum snout-vent length of 36.8 mm., and females reach 39.9 mm. In a series of 21 males from the north slope of Cerro Pando, Rocas del Toro Prov- ince, Panama, the snout-vent length is 31.2 to 36.8 (mean, 34.1) mm.; the ratio of tibia length to snout-vent length is 0.465 to 0.552 ( mean, 0.493 ) ; the ratio of foot length to snout-vent length is 0.375 to 0.433 (mean, 0.409); the ratio of head length to snout- vent length is 0.325 to 0.350 (mean, 0.335); the ratio of head width to snout-vent length is 0.334 to 0.358 (mean, 0.347), and the ratio of the diameter of the tympanum to that of the eye is 0.588 to 0.765 (mean, 0.661). In 12 females from the same locality, the snout- vent length is 36.3 to 39.9 (mean, 37.8) mm. Females differ from males by having a slightly larger tympanum; the ratio of the diameter of the tympanum to that of the eye in females is 0.628 to 0.780 (mean, 0.696). Little geo- graphic variation is noticeable in size and proportions. Specimens from the Pacific slopes of the Costa Rican highlands have a slightly shorter hind leg and narrower head, but larger tympanum. In eight males from the south slope of Cerro de la Muerte, Costa Rica, the ratio of tibia length to snout-vent length is 0.446 to 0.484 (mean, 0.468); the ratio of head width to snout-vent length is 0.316 to 0.339 (mean, 0.325), and the ratio of the diameter of the tvmpanum to that of the eye is 0.657 to 0.714' (mean, 0.693). The head is noticeably wider than the body, and the top of the head is barely con- vex. In dorsal and lateral profiles, the snout is truncate. The snout is long; its length is about equal to the length of the orbit. The nostrils are noticeably protuberant and are situated nearly at the tip of the snout; the internarial area is slightly depressed. The canthus is rounded; the loreal region is barely concave, and the lips are moderately thick but not flared. A heavy dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold obscures the upper one- fourth of the tympanum, which otherwise is distinct and separated from the eye by a dis- tance slightly less than the diameter of the tympanum. The arms are moderately long and slender; an axillary membrane is absent. A distinct dermal fold is present on the ventrolateral edge of the forearm, and a weak transverse dermal fold is present on the wrist. The fin- gers are moderately short and stout and bear moderate-sized discs; the width of the disc on the third finger is equal to about two-thirds of the diameter of the tympanum. The subar- ticular tubercles are large and conical; in many individuals, the distal tubercle on the fourth finger is bifid, and in some specimens, the distal tubercles on the second and third fingers are bifid. The supernumerary tubercles are low and indistinct in many specimens, whereas in others they form multiple rows on the basal segments of each digit. A low bifid palmar tubercle usually is evident. The prepollex is barely enlarged and in breeding males bears 1970 DUELLMAN: HYLID FROGS 303 Fig. 139. Hands and feet of members of the Hyla uranochroa group. A and C. Hyla uranochroa, K.U. No. 103767. B and D. Hyla rufioculis, K.U. No. 86453. x 5. a small, poorly developed nuptial excrescence. The fingers are about one-third webbed (fig. 139A). The webbing is vestigial between the first and second fingers and extends from the distal end of the antepenultimate phalanx of the second to the base of the antepenultimate phalanx of the third and on to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A transverse dermal fold is present on the heel, and a weak tarsal fold usually is evident distally on the tarsus. The inner metatarsal tubercle is rounded, ovoid, and barely visible from above. The outer metatarsal tubercle, if present, is low and subeonical. The toes are moderately long and slender and bear discs that are nearly as large as those on the fingers. The subarticu- lar tubercles are moderately large and sub- conical, and the supernumerary tubercles are small and present only on the proximal seg- 304 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 ments of the digits. The toes are about two- thirds webbed ( fig. 139C ) . The webbing ex- tends from the base of the penultimate pha- lanx of the first toe to the distal end of the antepenultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the middle of the antepenulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the third to the middle of the antepenultimate phalanx of the fourth and on to the distal end of the penulti- mate phalanx of the fifth toe. The anal opening is directed posteroven- trally near the upper level of the thighs. A short, broad anal sheath above and many large tubercles below the anus are present. The skin on the throat, belly, and proximal posteroventral surfaces of the thighs is granu- lar; elsewhere, the skin is smooth. The tongue is elongately ovoid, usually emarginate, and not free behind. The dentigerous processes of the prevomers are narrowly separated, pos- teromedial]}' inclined ridges between the mod- erately large, ovoid choanae. Males have three to six (mean, 4.8) and females have four to seven (mean, 5.1) teeth on each process. The vocal slits extend from the posterolateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and only moderately distensible. The general coloration of Hyla uranochroa is bright green above and yellow below (pi. 54, fig. 3 ) . Usually the dorsum is bright green with or without small yellowish flecks. The ventral surfaces and the anterior and posterior surfaces of the thighs, the inner edges of the feet, the fingers, and first four toes, as well as the webbing, are deep yellow. A narrow white stripe on the upper lip continues to the groin. There is a creamy white stripe on the upper arm and a white stripe on the outer edge of the forearm, the outer edge of the shank, and the outer edge of the foot. A white anal stripe usually is present, and the tubercles below the anal opening are white. The iris is bright red; in some individuals, the palpebral mem- brane is finely flecked with pale green. Little variation in coloration is present. Some individuals lack a white anal stripe, and in some specimens, the white labial stripe is expanded below the eye. The intensity of ventral pigment varies in living individuals. In some specimens, the lower flanks are deep yellow, whereas the midventral region and the throat are pale yellowish white; in all living individuals there is at least a tint of yellow on the venter. In preservative, the dorsum is dull bluish purple; this color is present on the dorsal sur- faces of the arms and basal segments of the fourth finger, as a narrow dorsal stripe on the length of the thigh, on the dorsal surfaces of the shank, feet, and fourth and fifth toes. The anterior and posterior surfaces of the thighs are creamy tan, and the venter is creamy white. Tadpoles: Several developmental series of tadpoles are available; the growth of the tad- poles in relation to developmental stages is summarized in table 34. A typical tadpole in developmental stage 26 has a body length of 11.3 mm. and a total length of 33.0 mm. The body is ovoid, slightly depressed, and barely wider than deep. In dorsal profile, the snout is rounded; in lateral profile, the snout is acuminate. The eyes are moderately small, widely separated, and di- rected dorsolaterally. The nostrils are directed anterolaterally at a point slightly closer to the eyes than to the tip of the snout. The opening of the sinistral spiracle is directed posteriorly at a point below the midline about two-thirds of the length of the body. The anal tube is moderately long and dextral. The caudal mus- culature is robust and extends nearly to the tip of the rounded tail. The caudal fins are low; the dorsal fin does not extend onto the body. At midlength of the tail, the depth of the caudal musculature is noticeably greater than the depth of either fin (fig. 140A). The body is dull olive-brown with bluish green flecks on the dorsum and flanks. The caudal musculature is pale creamy tan with brown spots. Minute white flecks are present on the tail. The iris is bright red. In pre- servative, the body is dark brown; the caudal musculature is pale tan with brown flecks. The caudal fins are transparent with small brown flecks, especially dorsally. The mouth is ventral, large, and funnel- shaped. Lateral folds are lacking, and the mouth is entirely bordered by a row of minute papillae. Large conical papillae are present in the mouth. The beaks are relatively small 1970 DUELLMAN: HYLID FROGS 305 Stage TABLE 34 Measurements of Tadpoles, with Means in Parentheses, in Relation to Developmental Stages, of HyJa uranochroa from Cinchona and Isla Bonita, Costa Rica. N Body Length Tail Length Total Length 25 - 13 26 3 27 _ 2 28 6 29 9 30 _..... 9 31 7 32 3 33 2 34 7 35 4 36 3 37 6 38 1 39 2 40 7 41 10 42 1 45 1 46 4 5.9-11.0 (8.9) 11.2-11.4 (11.3) 11.7-11.8 (11.8) 11.2-12.8 (12.0) 11.6-13.2 (12.2) 11.6-13.2 (12.5) 12.0-14.7 (13.3) 13.0-14.1 (13.4) 12.1-13.4 (12.8) 13.0-13.8 (13.3) 12.4-14.6 (13.5) 12.8-13.7 (13.3) 12.3-13.7 (13.1) 13.6 14.6 12.7-14.6 (13.5) 13.0-14.7 (14.0) 14.9 15.1 17.0-19.8 (18.5) 11.3-26.1 20.6-26.8 24.2-26.7 24.9-27.6 26.4-30.0 23.2-32.9 28.0-36.0 29.9-34.8 26.8-32.0 26.7-32.0 25.9-33.3 31.8-33.9 27.6-32.3 37.0 32.7-37.7 27.5-35.5 32.1-39.1 20.8 3.1 18.8) 23.8) 25.5) 26.3) 27.9) 28.8) 30.9) 32.0) 29.4) 29.5) 30.5) 32.6) 29.5) 35.2) 31.6) 35.1) 17.2-37.0 32.0-38.2 36.0-38.4 37.1-39.6 38.1-43.2 35.2-46.0 40.7-50.7 43.1-48.9 38.9-45.4 39.8-45.3 38.3-50.0 44.9-47.6 41.2-45.1 50.6 47.3-52.3 40.0-52.3 46.4-53.6 35.7 18.2 27.6) 35.1) 37.2) 38.3) 40.2) 41.3) 44.2) 45.5) 42.2) 42.8) 44.0) 45.9) 42.6) 49.8) 47.1) 49.1) and bear elongate pointed serrations. The upper beak is in the form of a broad arch lacking lateral processes and having a median ventral notch. The lower beak is slender and broadly V-shaped. There are two upper and two or three lower rows of teeth. The rows are short; none extends much beyond the lateral edge of the beaks. The first upper row is narrowly interrupted medially, and in some specimens the first lower row is interrupted. The third lower row, when present, is notice- ably shorter than the other rows (fig. 141A). Mating Call: The call of Hy la urano- chroa consists of a series of melodic bell-like notes "boop-boop-boop-boop." Recordings are available from the Pacific slopes of Cerro de • ■&*■»'* r» 1^«*# *?*„ -,^< Fig. 140. Tadpoles of members of the Hyla uranochroa group. A. Hyla uranochroa, K.U. No. 104248. B. Hyla rufioculis, K.U. No. 104159. X 3. 306 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 {* p ■ Fig. 141. Mouths of tadpoles of the Hyla urano- chroa group. A. Hyla uranochroa, K.U. No. 104248. B. Hyla rufioculis, K.U. No. 104159. X 11. la Muerte and Cinchona, Costa Rica, and from the north slope of Cerro Pando, Panama. In recordings from the latter locality, the note repetition rate is 50 and 60 notes per minute, and the notes have a duration of 0.05 and 0.06 of a second. The pulse rate is 240 and 280 pulses per second; the fundamental frequency is 1043 and 1143 cycles per second and the dominant frequency is 2086 and 2226 cycles per second (pi. 21, fig. 3). In the calls from Costa Rica, the note repetition rate is 217 and 264 notes per minute and the duration of the notes is 0.03 and 0.04 of a second. The pulse rate is 240 and 280 pulses per second; the fundamental frequency is 870 and 913 cycles per second, and the dominant frequency is 1740 and 1826 cycles per second (pi. 21, fig- 3). All these recordings were made at temper- atures between 18 and 20 degrees centigrade. Possibly there is geographic variation in the call, or perhaps there are individuals that pro- duce fast calls and others that produce slow calls. Natural History: Hyla uranochroa is an inhabitant of humid montane forests; the frogs usually are found in the proximity of montane streams. By day, individuals have been found in bromeliads. At night, they congregate along the streams. Calling males usually are in dense vegetation several meters away from the stream. Males seldom call from vegetation at the edge of, or over, the stream. Although this species apparently is active throughout the year, breeding activity seems to reach a peak in May and June. The tadpoles inhabit quiet pools in the stream; they most frequently are found in silt- bottomed pools where they take refuge amidst debris on the bottom. Remarks: Taylor (1952c, p. 831) named Hyla alleei from Isla Bonita, Heredia Prov- ince, Costa Rica. Duellman (1966, p. 276) provided evidence that the characters used by Taylor to diagnose Hyla alleei from urano- chroa are extremely variable and suggested that Hyla alleei is a synonym of Hyla urano- chroa. Savage (1968, p. 15) substantiated this assignment. Etymology: The specific name urano- chroa is derived from the Greek ouranos, meaning sky, and chroa, meaning the color of the skin. The name evidently alludes to the blue color of the dorsum in preserved speci- mens. Distribution: Hyla uranochroa inhabits humid montane forests in the mountains of Costa Rica and western Panama (fig. 142). The total altitudinal range of this species is from 600 to 1720 meters. On the Pacific slopes, which are usually drier than the Caribbean slopes, this species only descends to about 1400 meters, whereas on the Caribbean slopes it descends to 600 meters. At several places throughout the range, Hyla uranochroa occurs sympatrically with Hyla rufioculis; these places usually are near the upper limits of the range of the latter species. For example, on the southern slopes of Cerro de la Muerte, Costa Rica, Hyla uranochroa descends to 1600 meters, the highest elevation attained there by Hyla rufioculis. See Appendix 1 for the locality records of the 202 specimens examined. 1970 DUELLMAN: HYLID FROGS 307 Fig. 142. Distribution of Hyla uranochroa. Hyla rufioculis Taylor Hyla rufioculis Taylor, 1952c, p. 827 [holotype, K.U. No. 28216 from Isla Bonita, Heredia Province, Costa Rica; Richard C. Taylor and Edward H. Taylor collectors]. Hyla lythrodes Savage, 1968, p. 1 [holotype, L.A.C.M. No. 26766 from 21 kilometers southwest of Amburi at confluence of the Rio Lari and Rio Dipnari, Limon Province, Costa Rica; Jay M. Savage and Norman J. Scott, Jr. collectors]. Diagnosis: This moderately small brown or green Hyla with red eyes, truncate snout, little webbing, and a white lateral stripe is distinguished from its apparent close relative, H. uranochroa, by having a proportionately smaller tympanum (less than 50 per cent of the diameter of the tympanum in rufioculis and more than 50 per cent in uranochroa), shorter snout, pigmented plantar surfaces of the feet, and a white labial stripe that usually is expanded below the eye (not expanded in uranochroa). Hyla legleri and erythromma also have red eyes; the former is larger and has more webbing, a darker dorsum, and a dark throat in breeding males; the throat is white in rufioculis. Hyla erythromma has mot- tled brown and white flanks, acutely rounded snout, and more webbing than does rufioculis. Description: Males of this small species reach a maximum snout-vent length of 30.0 mm., and females attain 39.9 mm. In a series of 25 males from Finca Moravia, Cartago Province, Costa Rica, the snout-vent length is 25.4 to 28.8 (mean, 26.7) mm.; the ratio of tibia length to snout-vent length is 0.500 to 0.591 (mean, 0.536); the ratio of foot length 308 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 to snout-vent length is 0.395 to 0.472 (mean, 0.430 ) ; the ratio of head length to snout- vent length is 0.377 to 0.389 (mean, 0.362); the ratio of head width to snout-vent length is 0.354 to 0.394 (mean, 0.372), and the ratio of the diameter of the tympanum to that of the eye is 0.312 to 0.441 (mean, 0.361). In six females from the same locality the snout- vent length is 33.5 to 34.9 (mean, 34.1) mm.; the females do not differ significantly in pro- portions from the males. Samples were mea- sured from the south slopes of Cerro de la Muerte and from a locality 16 kilometers west- southwest of San Isidro El General, Costa Rica. Males in the former sample were sig- nificant in having relatively shorter hind limbs. The ratio of tibia length to snout-vent length is 0.474 to 0.537 (mean, 0.506). In the latter sample, the males are noted for having a smaller tympanum, the ratio of the diameter of the tympanum to that of the eye is 0.302 to 0.356 (mean, 0.332). Two males and three females from El Tigre, Limon Province, Costa Rica are distinctive in their large size. The males have snout-vent lengths of 29.4 and 30.0 mm., and the females have snout-vent lengths of 38.5, 39.2, and 39.9 mm. These frogs differ from other samples by having a relatively larger tympanum; in the five speci- mens the ratio of the diameter of the tym- panum to that of the eye is 0.415 to 0.452 (mean, 0.425). Another individual (L.A.C.M. No. 26766) from the Rio Lari, Limon Province, Costa Rica, has a snout-vent length of 30.2 mm. and the ratio of the diameter of the tym- panum to that of the eye, 0.555. The head is slightly wider than the body, the top of the head is barely convex. The snout is truncate in dorsal and lateral profiles. The snout is moderately long; its length is equal to about three-fourths of that of the orbit. The nostrils are slightly protuberant at a point near the tip of the snout; the inter- narial area is noticeably depressed. The can- thus is round; the loreal region is barely con- cave, and the lips are moderately thick and not noticeably flared. A thin dermal fold ex- tends posteriorly from the eye, above the tym- panum, and downward to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance equal to half again the diameter of the tympanum. The arms are moderately long and slender; an axillary membrane is absent. In some indi- viduals, small tubercles tend to form an in- distinct row along the ventrolateral edge of the forearm; a thin transverse dermal fold is evident on the wrist in some individuals. The fingers are moderately long and slender and bear small discs; the width of the disc on the third finger is equal to the diameter of the eye. The subarticular tubercles are small and subconical; the distal tubercle on the fourth finger is bifid in most individuals, and in some specimens, the distal tubercle on the third finger is weakly bifid. The supernumerary tubercles are small, indistinct, and numerous on the proximal segments of each digit. A moderately elevated, usually bifid, palmar tu- bercle is present. The prepollex is barely enlarged and in breeding males bears a horny nuptial excrescence. The fingers are about one-fourth webbed ( fig. 139R ) . The webbing is vestigial between the first and second fingers and extends from the base of the penultimate phalanx of the second to the base of the ante- penultimate phalanx of the third and on to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are mod- erately long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to a point just anterior to the eye. A thin, transverse dermal fold is present on the heel, and a weak tarsal fold is present distally on the tarsus; in some speci- mens, there is no evidence of a tarsal fold. The inner metatarsal tubercle is rounded, ovoid, and barely visible from above. Usually a distinct outer metatarsal tubercle is absent. The toes are moderately long and slender and bear discs that are only slightly smaller than those on the fingers. The subarticular tuber- cles are moderately small and subconical, and the supernumerary tubercles are low and in- distinct. The toes are about two-thirds webbed (fig. 139D). The webbing extends from the base of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the distal end of the penulti- mate phalanx of the second to the middle of the antepenultimate phalanx of the third, 1970 DUELLMAN: HYLID FROGS 309 from the middle of the penultimate phalanx of the third to the base of the penultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally near the upper level of the thighs. A short, broad anal sheath is present, and nu- merous small tubercles are present below the anal opening. The skin on the throat, belly, and posteroventral surfaces of the thighs is granular; elsewhere, the skin is smooth. The tongue is elongately ovoid or narrowly eordi- form, shallowly notched posteriorly and barely free behind. The dentigerous processes of the prevomers are widely separated, postero- medially inclined ridges between the large ovoid choanae. Males have two to five ( mean, 3.0) and females, four to six (mean, 4.9) teeth on each process. The vocal slits extend from the posterolateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and only moderately dis- tensible. The general coloration of Hyla rufioculis is dull brown or olive-green above and creamy white below (pi. 54, fig. 1). Most individuals are olive-green or dull brown above, but some specimens are bright green above. A silvery white line is present on the margin of the upper lips and extends to the groin. In most specimens, this stripe is expanded below the eye. A narrow white stripe is present on the outer edge of the forearm and outer edge of the tarsus. The elbows, heels, and knees are white and an elongate white mark is present on the dorsal surface of the upper arm. The anterior and posterior surfaces of the thighs are dull tan. A pair of white spots are present above the anal opening in most specimens, whereas in some others, there are no marks whatsoever. The belly is creamy white, and the vocal sac is white. The iris is bright red. In preservative, the dorsum varies from dull reddish brown to dull bluish purple. This color diminishes on the dorsal surfaces of the thighs, and in approximately half of the speci- mens, invades the posterior surfaces of the thighs. The ventral surfaces are pale creamy white, and the stripes on the lips, limbs, and flanks are white. In most specimens, there is some dark demarcation between the creamy white venter and the white lateral stripe. This usually is most evident in the axillary region and consists of a narrow brown line or series of dashes. Tadpoles: A developmental series of tad- poles is available from a stream 15 kilometers west-southwest of San Isidro el General, Costa Rica (table 35). A typical tadpole in developmental stage 28 has a body length of 11.4 mm. and a total length of 38.3 mm. The body is broadly ovoid and slightly wider than deep. In dorsal profile the snout is bluntly round, and in lateral pro- file it is acutely round. The eyes are moder- ately small, widely separated, and directed dorsolaterally. The nostrils are directed an- terolaterally at a point about midway between the eyes and the tip of the snout. The open- ing of the sinistral spiracle is directed pos- teriorly at a point just below the midline and just posterior to the midlength of the body. The caudal musculature and fins extend nearly to the tip of the rounded tail. The fins are shallow, and the dorsal fin does not extend on to the body. At midlength of the tail, the depth of the caudal musculature is equal to the combined depth of the dorsal and ventral fins (fig. 140R). The dorsum is dull olive-brown, and the flanks are somewhat paler with bluish white flecks. The caudal musculature is pale brown with a heavy suffusion of brown flecks and small spots, which also extends onto the fins. The iris is red. In preservative, the body is brown, and the caudal musculature is pale tan with dark brown flecks. The mouth is ventral, large, and funnel- shaped. The lips are completely bordered by a single row of minute papillae; lateral folds are lacking. Numerous large papillae are present in the mouth. The beaks are moder- ately robust and bear long, pointed serrations. The upper beak is in the form of a broad arch without lateral processes, and the lower beak is broadly V-shaped. There are two up- per and two or three lower rows of teeth. The rows are short and barely extend beyond the lateral extent of the beaks. The first upper tooth row is narrowly interrupted medially. The second row and, when present, third lower tooth row are shorter than the first low- er row (fig. 141B). Mating Call: The call of Hyla rufioculis 310 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TARLE 35 Measurements of Tadpoles, with Means in Parentheses, in Relation to Developmental Stages, of Hyla rufioculis from 15 Kilometers West-Southwest of San Isidro El General, Costa Rica. Stage N Body Length Tail Length Total Length 25 11 26 3 27 3 28 _.. 3 29 2 31 2 32 ..__ 1 34 _ 1 35 4 37 2 40 2 41 ..... __.__ 3 44 1 46 3 4.7-11.6 (8.3) 9.6-26.5 (18.1) 14.3-38.1 (23.7) 9.1-11.6 (10.1) 18.5-25.6 (21.7) 27.6-37.2 (31.8) 10.1-10.8 (10.5) 20.5-22.9 (22.0) 31.2-33.7 (32.5) 10.1-11.8 (11.1) 23.6-27.0 (23.8) 33.7-38.3 (35.9) 12.0-12.4 (12.2) 25.6-28.9 (27.3) 37.6-41.3 (39.5) 11.6-11.8 (11.7) 26.8-27.7 (27.3) 38.6-39.3 (39.0) 12.0 25.6 37.6 11.9 27.7 39.6 12.4-13.0 (12.8) 19.0-30.5 (26.2) 31.8-43.5 (39.0) 12.0-13.0 (12.5) 26.8-30.0 (29.4) 38.8-43.0 (40.9) 12.8 30.8-31.7 (31.3) 43.6-44.5 (44.1) 11.6-11.8 (11.7) 22.6-31.2 (27.3) 34.3-43.0 (38.9) 14.7 18.7 33.4 15.5-16.1 (15.9) consists of a short rattle. Each call group con- sists of three or four short notes. The interval between call groups varies from three to 18 (mean, 6.1) seconds. The duration of notes is 0.05 to 0.07 (mean, 0.06) of a second. The fundamental frequency varies from 78 to 95 (mean, 87) cycles per second, and the domi- nant frequency varies from 2070 to 2570 ( mean, 2320 ) cycles per second ( pi. 22, fig. 1 ) . Natural History: Hyla rufioculis is an in- habitant of humid montane forests where this species is active throughout the year, except at times of little rain. Males call from branches of bushes at the edge of, or over, small streams. The tadpoles develop in quiet pools in the stream, where they seek refuge amidst debris on the bottom of the pools. Remarks: Savage (1968, p. 1) named Hyla lythrodes on the basis of a single male from the Rio Lari, Limon Province, Costa Rica. Savage stated that lythrodes "approaches rufioculis of Atlantic and Pacific Costa Rica but is distinct in morphology and limb colora- tion. H. rufioculis has a small tympanum, scarcely larger than the largest finger disc and less than one-third the diameter of the orbit and the posterior surface of the thighs suffused with dark pigment." Examination of the holotype of Hyla ly- throdes (L.A.C.M. No. 26766) reveals only one character that will separate this specimen from the several large series of H. rufioculis that have been examined. The holotype of ly- throdes has a relatively large tympanum; the ratio of the diameter of the tympanum to that of the eye is 0.555. The highest ratio in any specimen assigned to rufioculis is 0.441. The coloration on the posterior surface of the thighs (light in lythrodes and supposedly dark in rufioculis ) is highly variable in rufioculis. Ex- cept for the proportionately large tympanum, I can find no characters by which to separate lythrodes from rufioculis and suggest that ly- throdes be placed in the synonymy of Hyla rufioculis. This assignment might be proven to be incorrect on the basis of presently un- available biological information. Savage ( 1968, p. 6) stated that the call of the single male of lythrodes differed from the calls of rufiocu- lis and uranochroa. The absence of recordings precludes an objective comparison. Etymology: The specific name is derived from the Latin rufus, meaning red, and the Latin oculus, meaning eye, and refers to the red eye that is characteristic of this species. Distribution: Hyla rufioculis inhabits the Atlantic and Pacific slopes of all of the moun- tain ranges in Costa Rica from elevations of 775 meters to 1580 meters (fig. 143). 1970 DUELLMAN: HYLID FROGS 311 11° 85° 83° I m° ) • \ 7 • \ f \ \ j i i 9° 0 50 100 \ 1 9° KILOMETERS i \ \ 1 1 ~J^£t- 85° 83° Fig. 143. Distribution of Hyla rufioculis. See Appendix 1 for the locality records of the 388 specimens examined. The Hyla lancasteri Group Definition: The frogs comprising this group are moderately small stream-breeders; males attain a snout-vent length of 33.6 mm. and females, 41.1 mm. The dorsum is mottled shades of brown or green and gray. The dor- sal surfaces of the limbs are marked by trans- verse bars, and the anterior and posterior sur- faces of the thighs are white or yellow with black spots or vertical bars. The venter is white and heavily mottled with black in some populations. The palpebral membrane is clear. The snout is exceedingly short and truncate. The fingers are about one-third webbed, and the toes are about three-fourths webbed. A well-developed tarsal fold is present, but an axillary membrane is absent. Dermal fleshy protuberances are present on the dorsum and on the limbs in some populations. Males have a single, median, subgular vocal sac and horny nuptial excrescences on the prepollices. The skull is moderately well ossified with a small ovoid frontoparietal fontanelle (fig. 144). The sphenethmoid is large and broad and does not extend anteriorly between the small, slender nasals, which articulate with the sphenethmoid anterolaterally. A quadratojugal is present. The squamosal articulates with the crista paro- tica, and the anterior arm of the squamosal extends about one-third of the distance to the maxillary. The medial ramus of the pterygoid is in bony contact with the prootic. The pre- 312 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 144. Dorsal view of the skull of Htjla lan- casteri, K.U. No. 101601. x 6. vomers articulate anteriorly and bear large, transverse dentigerous processes. The tad- poles have moderately long muscular tails and moderately enlarged ventral mouths with two upper and three lower rows of teeth. The mating call consists of a single or paired rat- tling note. The number of chromosomes is unknown. Composition: One species, Hyla lancas- teri, is included in this group, which is en- demic to the Caribbean slopes of Costa Rica and western Panama. One hundred ninety-five preserved frogs, eight skeletons, 15 lots of tad- poles, and three preserved clutches of eggs have been examined. Comments: Hyla lancasteri is another of the Middle American species that apparently has no close relatives. Superficially, lancasteri is similar to the Mexican Hyla thorectes; fur- thermore, both species deposit eggs on vege- tation above streams and have relatively un- specialized stream tadpoles. Hyla thorectes has more reduced cranial elements than lan- casteri; in the former the quadratojugal is ab- sent, the squamosal is not in bony contact with the crista parotica, and the medial ramus of the pterygoid does not have a bony articu- lation with the prootic. Bokermann (1964) suggested that Hyla moraviaensis (=lancasteri) is related to the Amazonian Hyla marmorata. The latter has a short, truncate snout like that of lancasteri, but marmorata has extensive webbing, axillary membranes and fringes on the limbs; the tad- poles are pelagic types with a terminal mouth and deep fins on the xiphicercal tail, Hyla lancasteri Barbour Hyla lancasteri Barbour, 1928, p. 31 [holotype, M.C.Z. 13062 from Peralta, Cartago Province, Costa Rica; C. R. Lancaster collector]. Duellman, 1966b, p. 271 [synonymized Hyla moraviaensis Taylor, 1952, with Hyla lancasteri Barbour, 1928]. Trueb, 1968a, p. 285. Hyla boulengeri (in part): Dunn and Emlen, 1932, p. 25. Taylor, 1952c, p. 856. Cochran and Goin, 1970, p. 243. Hyla moraviaensis Taylor, 1952c, p. 865 [holotype, K.U. No. 30284 from Moravia, Cartago Province, Costa Rica; Edward H. Taylor collector]. Diagnosis: This moderately small species differs from all other Middle American hylids by having an extremely short, truncate snout. The dorsum is mottled brown or green and gray, and the anterior and posterior surfaces of the thighs are yellow with black vertical bars or white with black spots. Hyla boulen- geri and rostrata have vertical black bars on the thighs, but both of these frogs have long, protruding snouts. Hyla thorectes has a short, truncate snout but lacks vertical bars on the thighs. Description: Males of this moderately small species attain a maximum snout-vent length of 33.6 mm. and females reach 41.1 mm. In a series of 23 males from 3 kilo- meters south of Pavones, Cartago Province, Costa Rica, the snout-vent length is 27.6 to 31.5 (mean, 29.1) mm.; the ratio of tibia length to snout-vent length is 0.490 to 0.557 (mean, 0.517); the ratio of foot length to snout-vent length is 0.311 to 0.434 (mean, 0.413); the ratio of head length to snout-vent length is 0.242 to 0.336 (mean, 0.304); the ratio of head width to snout-vent length is 0.322 to 0.373 (mean, 0.345), and the ratio of the diameter of the tympanum to that of the eye is 0.429 to 0.588 ( mean, 0.471 ) . One female from the same locality has a snout-vent length of 37.5 mm. and does not differ signifi- cantly from the males in proportions. Throughout the range of the species in the Caribbean foothills of Costa Rica and western Panama there is little variation in size and proportions; however, in the highlands of western Panama there are some noticeable differences. For example, on Cerro Pando, in 1970 DUELLMAN: HYLID FROGS 313 extreme western Panama, there is an altitu- dinal decrease in snout-vent length, head length, diameter of the tympanum, and diam- eter of the eye, but there is no significant change in head width or in foot length. These differences are illustrated in a series of eight males from an elevation of 1920 meters on the north slopes of Cerro Pando, Bocas del Toro Province, Panama. The snout-vent length is 28.0 to 30.6 (mean, 28.9) mm.; the ratio of tibia length to snout-vent length is 0.520 to 0.567 (mean, 0.543); the ratio of foot length to snout-vent length is 0.435 to 0.487 ( mean, 0.466 ) ; the ratio of head length to snout-vent length is 0.304 to 0.330 (mean, 0.318); the ratio of head width to snout-vent length is 0.337 to 0.382 (mean, 0.363), and the ratio of the diameter of the tympanum to that of the eye is 0.371 to 0.429 ( mean, 0.397 ) . Trueb ( 1968a ) gave a detailed statistical anal- ysis of the altitudinal variation in measure- ments of this species. The head is as wide as the body, and the top of the head is flat. The eyes are large and prominent. In dorsal profile, the snout is truncate; in lateral profile, it is truncate and barely posteroventrally inclined. The snout is extremely short, and the nostrils are noticeably protuberant at the anterior extrem- ity of the snout. The distance between the anterior edge of the eye and the nostril is approximately equal to the diameter of the eye. The canthus is angular, and the loreal region is barely concave; the lips are thick and barely flared. A moderately heavy dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold ob- scures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance slightly less than the diam- eter of the tympanum. The arms are moderately long and robust; an axillary membrane is absent. A row of small tubercles is present on the ventrolateral edge of the forearm, and a transverse dermal fold is present on the wrist. The fingers are moderately long and robust and bear moder- ately large discs; the width of the disc on the third finger is slightly larger than the diameter of the tympanum. The subarticular tubercles are moderately large and subcorneal; the dis- tal tubercle on the fourth finger is bifid in most specimens. The supernumerary tubercles are large and subcorneal. In specimens from high elevations on Cerro Pando many gran- ules are present on the palmar surfaces of the hands. A bifid or tripartite palmar tubercle is present. The prepollex is moderately enlarged and in breeding males bears a horny nuptial excrescence. In specimens, from the lowlands, this excrescence is composed of minute spin- ules, whereas in specimens from high eleva- tions on Cerro Pando, the excrescence is made up of a few large spines. The fingers are about one-third webbed in lowland populations (fig. MSA), and about half webbed in specimens from high elevations on Cerro Pando (fig. 145B). In both populations, the webbing be- tween the first and second fingers is vestigial; in lowland populations, the webbing extends from the base of the penultimate phalanx of the second finger to the base of the antepenul- timate phalanx of the third and from the middle of the antepenultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth finger, whereas in speci- mens from high elevations on Cerro Pando, the webbing extends from the base of the penultimate phalanx of the second to the mid- dle of the antepenultimate phalanx of the third and from the distal end of the antepenul- timate phalanx of the third to the base of the penultimate phalanx of the fourth finger. The hind limbs are moderately short and robust; the heels of the adpressed limbs overlap by about one-fourth to one-third of the length of the shank. The tibiotarsal articulation ex- tends to the middle of the eye. A transverse dermal fold is present on the heel, and a weak tarsal fold is evident on the distal half of the tarsus. The inner metatarsal tubercle is low, flat, and elliptical; the outer metatarsal tu- bercle is small and subcorneal. The toes are moderately short and robust and bear discs that are nearly as large as those on the fingers. The subarticular tubercles are moderately large and subcorneal, and the supernumerary tubercles are nearly as large as the subarticu- lar tubercles and conical in shape. The toes are about three-fourths webbed (fig. 145C and D). The webbing extends from the mid- dle of the penultimate phalanx of the first toe to the distal end of the antepenultimate 314 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 145. Hands and feet of Htjla lancasteri from lowlands (A and C, K.U. No. 103672) and Cerro Pando (B and D, K.U. No. 101736). X 6. 1970 DUELLMAN: HYLID FROGS 315 phalanx of the second, from the distal end of the antepenultimate phalanx of the second to the distal end of the antepenultimate pha- lanx of the third, from the distal end of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth and on to the middle of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally near the upper level of the thighs. A short, narrow anal sheath is present. The chest, belly, and proximal posteroventral sur- faces of the thighs are strongly granular. In individuals from the lowlands, the skin on the top of the head and on the back is weakly tu- berculate; elsewhere, the skin is smooth. In specimens from high elevations on Cerro Pan- do the dorsal surfaces of the head, body, fore- arms, shanks, and feet, are covered with large fleshy protuberances that give the impression of spines. Usually three large pointed tuber- cles are present on the upper eyelid and two or more are present on the top of the head between the eyes. At least two large spines are present in the scapular region, and smaller spines are present elsewhere on the dorsum. A row of spines is present on the dorsolateral edge of the forearm, and a similar row is pres- ent on the dorsolateral edge of the shank and outer edge of the foot. The tongue is nearly round or broadly cordiform, shallowly notched posteriorly, and barely free behind. The den- tigerous processes of the prevomers are short transverse elevations between the posterior margins of the small ovoid choanae. Males have three to five teeth on each process and a total of six to nine (mean, 7.5) prevomerine teeth; females have six or seven teeth on each process and a total of 12 to 14 (mean, 13.0) prevomerine teeth. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Hijla lancasteri in the Caribbean foothills is mottled green and brown dorsally with black and yellow flash marks on the thighs ( pi. 54, fig. 2 ) . When active at night the dorsum in most individuals is dark metallic green with brown flecks. By day, the dorsum varies from pale tan to me- tallic green with brown spots or mottling. The groin, anterior and posterior surfaces of the thighs, the inner edges of the shanks and tarsi are bright yellow with black bars. The anal region is white. The chin and chest are silvery white, and the belly and ventral sur- faces of the limbs are grayish white. The iris is reddish brown. The general coloration of individuals from high elevations on Cerro Pando is green with brown flecks dorsally and lacks yellow pig- ment on the thighs (pi. 54, fig. 4). In most individuals from Cerro Pando, the dorsum is green with brown flecks and blotches. In some individuals, the tip of the snout is olive-green. The lips are barred with metallic greenish white and dark brown. The posterior part of the eyelid, angle of the jaw, tympanum, and the anterior part of the flanks are dark brown. The posterior part of the flank and the groin are white with dark brown spots. The dorsal surfaces of the thighs are greenish white with dark brown bars. The dorsal surfaces of the forelimbs, shanks, and tarsi are pale green with olive-brown bands. The fingers and toes are tan with brown markings. The chin, throat, and chest are white. The edge of the chin is marked with dark brown. The chest is spotted with black. The skin on the belly, ventral surfaces of the limbs, anterior and pos- terior surfaces of the thighs, and the axilla lacks pigment, except the white flecks and black spots. The iris is pale cream with cop- per-colored flecks dispersed throughout, but most concentrated in an anterior and posterior triangle with apices at the pupil. The coloration described for the lowland population is relatively constant throughout the foothills on the Caribbean slopes of Costa Rica and western Panama. At elevations of 830 meters on the Rio Changena, Bocas del Toro Province, Panama, the lowland colora- tion holds. The condition described for popu- lations at high elevations on Cerro Pando hold for individuals taken at elevations between 1450 and 1920 meters on the north slope of Cerro Pando. Individuals from the Rio Claro at an elevation of 910 meters are intermediate between the two color types described (see Trueb, 1968a, for detailed comparison). In preservative individuals from the low- lands and highlands alike generally are dull brown above with darker brown spots or mot- tling. The posterior part of the flanks and 316 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 - 3^'v^ «. Fig. 146. Tadpole of Hyla lancasteri, K.U. No. 104254. x 10. groin are white with dark brown or black mot- tling. Distinct transverse bands are evident on the limbs. The venter is creamy white and spotted with dark brown or black in indi- viduals from the highlands. Tadpoles: The tadpoles of Hyla lancasteri are exceedingly large. Tadpoles in develop- mental stage 25 have total lengths up to 36 mm.; the largest tadpole examined is in de- velopmental stage 41 and has a total length of 55 mm. A typical tadpole in developmental stage 37 has a body length of 16.2 mm. and a total length of 49.8 mm. The body is moder- ately depressed and only slightly wider than deep. In dorsal profile, the body is ovoid, widest just posterior to the eyes. The snout is bluntly rounded in dorsal profile and acute- ly rounded in lateral profile. The eyes are moderately large, broadly separated, and di- rected dorsolaterally. The nostrils are slightly protuberant, directed anterolaterally, and situ- ated about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posteriorly on the mid- line at a point about two-thirds of the distance from the tip of the snout to the posterior edge of the body. The anal tube is short and dex- tral. The caudal musculature is heavy and terminates somewhat short of the acutely rounded tail. The fins are moderately shallow; at midlength of the tail, the depth of the cau- dal musculature is somewhat greater than the depth of either fin. The dorsal fin does not extend onto the body (fig. 146). In tadpoles from a stream 3 kilometers south of Pavones, Cartago Province, Costa Rica, the dorsum is olive-brown with dark brown spots and green lichenous markings. The caudal musculature is tan with dark brown markings. The coloration of tadpoles from a stream at an elevation of 1450 meters on the north slope of Cerro Pando, Bocas del Toro Province, Panama, is more intense. The body is olive-brown with dark brown blotches and reticulations. The belly is pale bluish white. The caudal musculature is tan with bold dark brown spots, and the iris is pali' bronze. In preservative, the dorsum of the body is brown with a pair of longitudinal creamy tan areas commencing just posterior to the level of the eyes and extending to the posterior edge of the body. Numerous dark brown flecks and blotches are present on the dorsum and sides of the body. The venter is bluish gray with faint white flecks. The cau- dal musculature is creamy tan with dark brown blotches and flecks. The blotches tend to form transverse bars on the dorsal surfaces of the caudal musculature. Dark brown flecks are present on the dorsal fin and distally on the ventral fin. The mouth is ventral and rather small; its greatest width is equal to about three-fifths of the greatest width of the body. The lips are completely bordered by two rows of small papillae; lateral folds are present in the lips. Additional papillae are present in the lateral folds. The beaks are small but robust and bear long, conical serrations. The upper beak is in the form of a broad arch with moderately robust lateral processes; the lower beak is massive and U-shaped. There are two upper and three lower rows of teeth. The upper rows are long and extend laterally to the mar- gins of the lips. The second upper row is narrowly interrupted medially. The lower rows are shorter than the upper rows, approxi- mately equal in length, and complete (fig. 147).' The tadpoles of this species were first described by Starrett (1960a, p. 21) under the name of Hyla moraviensis (sic). Mating Call: The call of Hyla lancasteri at lower elevations in Costa Rica and Panama 1970 DUELLMAN: HYLID FROGS 317 ■"-, lie" Fig. 147. Mouth of tadpole of Hyla lancasteri, K.U. No. 104254. x 10. consists of a pair of short, high-pitched, poorly modulated notes, characterized by rapid pul- sation and usually three emphasized harmon- ics above the dominant frequency. The call at high elevations on Cerro Pando consists of a single longer note that has a slower pulse rate and only one emphasized harmonic above the dominant frequency (pi. 24, figs. 1 and 2). Seven recordings obtained at Pavones, Costa Rica, at temperatures of 21.7 to 22.2 degrees centigrade have note repetition rates of seven to 19 (mean, 12.5) notes per minute. The duration of the note varies from 0.01 to 0.08 (mean, 0.07) of a second, and the pulse rate varies from 135 to 160 (mean, 150) pulses per second; the dominant frequency varies from 1363 to 1727 (mean, 1525) cycles per second. Two recordings were obtained at an elevation of 1450 meters on Cerro Pando at the temperature of 16.7 degrees centigrade; these had a note repetition rate of 2.6 and 3.6 notes per minute. The notes have dura- tions of 0.35 and 0.37 of a second, and the pulse rate is 90 to 95 pulses per second. The dominant frequency is 1136 and 1181 cycles per second. The differences noted with the increased altitude are characteristic of the differences found with change in temperature. Natural History: Hyla lancasteri inhab- its humid montane forests characterized by rainfall throughout the year. Taylor ( 1952c, p. 868) obtained calling males at Moravia, Cartago Province, Costa Rica, in August, 1951. Starrett ( 1960a, p. 21 ) reported calling males from various localities in Cartago Province, Costa Rica, in July and August, 1957. I have found males calling in Cartago Province, Costa Rica, in the months of March through July. Males were calling at elevations of 1450 and 1920 meters on Cerro Pando in May, 1966. Tadpoles and recently metamorphosed young were obtained at an elevation of 740 meters in Cartago Province, Costa Rica, in March; Starrett ( 1960a, p. 21 ) obtained tad- poles on July 25 at an elevation of 926 meters on the south slope of Volcan Turrialba in Costa Rica. Trueb (1968a) noted that tad- poles and metamorphosing young were abun- dant in late May at elevations of 830 and 910 meters in western Panama and that at higher elevations, young tadpoles, eggs, and gravid females were found in early May. She suggest- ed that these data indicate that at lower eleva- tions, breeding starts earlier in the year and possibly is most intense in the months of January and February, whereas at higher ele- vations, breeding activity seems to be post- poned until the start of the rainy season in late April and early May. At low elevations in Costa Rica and Pan- ama, males call from low vegetation, the ground, and stones in and along small streams. At high elevations on Cerro Pando, where the limbs of bushes and trees are covered with heavy growths of moss, males typically call amidst the moss on the branches of trees over- hanging streams. Eggs have not been found at low eleva- tions, but at 1450 and 1920 meters on the north slope of Cerro Pando, clutches of eggs were found on leaves up to heights of 2 me- ters above the streams. Two clutches have 20 and 23 eggs each. Each egg is contained within its own envelope and is slightly more than 6 mm. in diameter. The eggs are depos- ited in bunches on the upper surfaces of leaves (pi. S, fig. 2). Trueb (1968a) suggested that the eggs probably are deposited in streams at lower elevations, because no eggs were ob- served on overhanging vegetation, although breeding activity was underway. The tadpoles develop in streams. In the rapidly moving streams at higher elevations the tadpoles are particularly found in shallow, gravel-bottomed pools; when disturbed, they take refuge amidst leaves and other debris on the bottom of the pools. The tadpoles liv- ing in the slower streams at lower elevations usually were found in quiet, silt-bottomed pools. Large individuals characteristically 318 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 concealed themselves beneath stones and de- bris whereas small tadpoles were found ad- hering with their mouths to the tops of stones or to leaves in the bottom of the small pool. Remarks : Trueb ( 1968a ) discussed in detail the striking character gradients in size, tuberosity, morphological characters of the hands and feet, coloration, mating call, and breeding behavior in this species on Cerro Pando in Panama; she pointed out that most of the clinal variation seems to be associated with environmental changes of temperature and habitat. When Trueb and I, accompanied by Charles W. Myers, obtained the first speci- men of the "spiny frog" on Cerro Pando in early May, 1966, we all felt that we had ob- tained a striking new species of tree frog. It was with some dismay, but considerable interest, that we traced the "spiny frog" down the mountain to Hyla lancasteri. The alti- tudinal gradients in morphology, coloration, and behavior in this species are the most striking in any known frog. The changes in tuberosity and coloration are especially well correlated with the density of moss on tree branches at higher elevations. Barbour (1928, p. 31) named Hyla lan- casteri on the basis on one juvenile having a snout- vent length of 19.1 mm. Dunn and Emlen (1932, p. 25) placed lancasteri in the synonymy of Hyla boulcngeri. Taylor ( 1952c, p. 868) questioned the allocation of Hyla lan- casteri and went on to name Hyla moraviaen- sis. Duellman ( 1966b, p. 271 ) noted that the type of Hyla lancasteri was not a juvenile specimen of boulengeri but instead was a ju- venile of the species named Hyla moraviaensis by Taylor. Etymology: The specific name is a patro- nym for C. R. Lancaster, the collector of the type specimen. Distribution: Hyla lancasteri occurs at elevations between 650 and 1920 meters on the Caribbean slopes of the highlands of Costa Rica and extreme western Panama (fig. 148). See Appendix 1 for the locality records of the 221 specimens examined. The Hyla zcteki Group Definition: The members of this group are small bromeliad inhabitants; males attain a maximum snout-vent length of 32.8 mm. and females, 35.2 mm. The dorsum is yellowish or orange-tan or pale brown with no distinctive markings. The palpebral membrane is clear. The webbing is vestigial on the fingers, and the toes are no more than half webbed. Der- mal fringes and appendages are lacking on the limbs, and an axillary membrane is pres- ent. The tympanum is partially or completely concealed. Males have a single, median, sub- gular vocal sac and moderately or greatly en- larged prepollices lacking nuptial excres- cences. There is a heavy muscular devel- opment in the temporal region. The skull is moderately well ossified; a large key-hole shaped frontoparietal fontanelle is present (fig. 149). The sphenethmoid is broad and extends anteriorly between the nasals, which are wide, adjacent to but not sutured to the sphenethmoid, and have moderately long maxillary processes. The quadratojugal is present (picadoi) or absent (zeteki). The squamosal is in bony contact with the crista parotica, and the anterior arm of the squa- mosal extends about two-fifths of the distance to the maxillary. The medial ramus of the pterygoid is not in bony contact with the prootic. The prevomers do not articulate an- teriorly; the dentigerous processes are small and posteromedially inclined. The known tadpoles have moderately long, muscular tails with reduced fins and a dorsal mouth lacking definitive rows of teeth. The mating calls and number of chromosomes are unknown. Composition: Two species (Hyla picadoi and zeteki) comprise the group, which occurs at high elevations in Costa Rica and western Panama. Forty-seven preserved frogs, two skeletons, and one lot of tadpoles have been examined. Comments: Although Hyla picadoi differs from zeteki by having two, instead of one, denticles on the lower jaw, the two species are alike in several characters: broad flat heads with heavy muscular development in the temporal region, granular area around the anal opening, granules above the insertion of the arm, partially or completely concealed tympanum, and greatly reduced webbing be- tween the fingers. This combination of exter- nal characters sets these two species apart from other Middle American hylids. 1970 DUELLMAN: HYLID FROGS 319 Fie. 148. Distribution of Hyla lancasteri. Hijla zeteki is the only member of the genus in lower Central America known to have tadpoles that develop in bromeliads. Further- more, it is the only species of Middle American hylids known to have tadpoles with a dorsal mouth. Because Hyla picadoi is structurally similar to zeteki and because picadoi also lives in bromeliads, it is likely that the tadpoles of picadoi develop in bromeliads. Tadpoles of picadoi and recordings of the mating calls of both species are needed before an assessment of relationships can be made. No real clues to the relationships of this group to other groups of Middle American Hyla are evident. The broemliad frogs of the Hyla bwmeliacia group in Mexico and north- ern Central America evidently are unrelated to the zeteki group. The species in the former group have tadpoles with small ventral mouths and differ from the zeteki group in a number of cranial characters. Perhaps the zeteki group represents a divergent line from a Hyla pseu- dopuma-\ike ancestor. Members of the pseu- dopuma group are generalized montane pond breeders in lower Central America. Hyla picadoi Dunn Hyla picadoi Dunn, 1937, p. 164 [holotype, M.C.Z. No. 16002 from Volcan Barba, Heredia Province, Costa Rica, 2140 meters; Emmett R. Dunn collector], Taylor, 1952c, p. 824. Diagnosis: This moderately small species has a broad head with a heavy muscular de- velopment in the temporal region, vestigial 320 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 149. Dorsal view of the skull of Hyla pica- doi, K.U. No. 64872. x 6. webbing on the hands, the toes only about half webbed, granular skin above the inser- tion of the arm, and the anal opening sur- rounded by granules. The tympanum is par- tially or completely concealed. It differs from all other Middle American hylids by having two, instead of one, denticles at the symphysis of the lower jaw. Hyla picadoi differs from its apparent closest relative, H. zeteki, by its larger size (males to 32.8 mm. in picadoi and only to 23.5 mm. in zeteki), heavier granular development on ventral surfaces of arms and above the insertion of arms, and in coloration — the lips, loreal region, and supratympanic fold usually are dark in picadoi, whereas only the lips are pigmented in zeteki. Description: Males of this moderately small species attain a maximum snout-vent length of 32.8 mm., and females reach 35.2 mm. In a series of five males from the high- lands of Costa Rica, the snout-vent length is 27.9 to 32.8 (mean, 30.7) mm.; the ratio of tibia length to snout-vent length is 0.463 to 0.527 ( mean, 0.501 ) ; the ratio of foot length to snout-vent length is 0.419 to 0.464 (mean, 0.436); the ratio of head length to snout-vent length is 0.317 to 0.362 (mean, 0.338); the ratio of head width to snout-vent length is 0.341 to 0.376 (mean, 0.354), and the ratio of the diameter of the tympanum to that of the eye is 0.433 to 0.467 (mean, 0.450). The head is broader than the body, and the top of the head is flat. In dorsal profile, the snout is truncate, but pointed terminally; in lateral profile, it is truncate. The snout is short; the nostrils are laterally protuberant at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is rounded, and the loreal region is nearly flat; the lips are moderately thick and barely flared. The temporal region of the head is somewhat expanded. A moderately heavy dermal fold extends posteriorly from the eye, above the tympanum, and on to a point above the insertion of the arm. The fold obscures the upper half of the tympanum, which otherwise is barely discernible or com- pletely concealed beneath the skin. The tym- panum is separated from the eye by a distance equal to about three times the length of the tympanum. The arms are moderately long and robust; an axillary membrane is lacking. No distinct row of tubercles is present on the ventrolateral edge of the forearm, but a distinct transverse dermal fold is present on the wrist. The fin- gers are moderately short and robust and bear moderately large discs; the width of the disc on the third finger is half again the diameter of the tympanum. The subarticular tubercles are moderately large and subcorneal; the distal tubercle on the fourth finger usually is bifid. The supernumerary tubercles are large, coni- cal, and especially numerous on the proximal segments of each digit. A moderately small, bifid palmar tubercle is present. The prepollex is only moderately enlarged; the extent of a nuptial excrescence in breeding males is not known. The webbing between the fingers is vestigial (fig. 150A). The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A heavy transverse dermal fold is present on the heel, and a heavy, glandular tarsal fold extends the full length of the tarsus. Three or four conical tubercles are present on the proximal outer edge of the foot. The inner metatarsal tubercle is elongate and elliptical. The outer metatarsal tubercle is small and subcorneal. The toes are moderately long and slender and bear discs that are nearly as large as those on the fingers. The subarticular tu- bercles are small and conical, and the super- 1970 DUELLMAN: HYLID FROGS 321 Fig. 150. Hands and feet ot members ot the Hyla zcteki group. A and C. Hyla picadoi, K.U. No. 65129. B and D. Hyla zeteki, K.U. No. 36480. X 8. 322 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 numerary tubercles are moderately large and subcorneal. The toes are about two-fifths webbed ( fig. 150C ) . The webbing is vestigial between the first and second toes, and extends from the distal end of the antepenultimate phalanx of the second to the base of the ante- penultimate phalanx of the third, from the base of the penultimate phalanx of the third to the base of the antepenultimate phalanx of the fourth and on to the base of the penulti- mate phalanx of the fifth toe. The anal opening is directed posteriorly near the upper level of the thighs. A granular anal tube is present, and many large granules are present below the anal opening. The skin on the side of the body above the insertion of the arm is weakly granular. The skin on the belly, ventral surfaces of the arms, and proxi- mal posteroventral surfaces of the thighs is strongly granular; elsewhere, the skin is smooth. The tongue is broadly ovoid, emargi- nate, and barely free posteriorly. The den- tigerous processes of the prevomers are nar- rowly separated, posteromedially inclined elevations between the posterior margins of the small, round choanae. Males have two or three teeth on each process and a total of four to six (mean, 5.3) prevomerine teeth. One adult female has a total of nine prevomerine teeth. A pair of denticles is present at the symphysis of the lower jaw. The vocal slits extend from the midlateral base of the tongue to the angles of the jaw. The vocal sac is single, median, and subgular. The general coloration of Hyla picadoi con- sists of a yellowish tan dorsum with olive- brown or brown markings ( pi. 52, fig. 1 ) . The dorsum usually is nearly uniform yellowish tan or orange-tan; the groin in some individ- uals has a greenish east. The belly is white, and the ventral surfaces of the hind limbs and throat are yellow. The iris is reddish copper. The sides of the head and the supratympanic fold usually are pigmented with brown or olive-brown. A dark spot usually is present on the top of the head and sometimes extends posteriorly as an irregular middorsal stripe. The temporal region is orange in many speci- mens. One individual (U.S.C. No. 7081) from 1 kilometer southeast of La Chonta, Cartago Province, Costa Rica, had a brown dorsum with heavy yellow flecking in life; the upper surfaces of the hind limbs were reticulated with brown and yellow. Another individual (U.S.C. No. 668) from El Empalme, Costa Rica, had a metallic golden orange dorsum with an olive cast in life; the head was espe- cially metallic gold (J. M. Savage field notes). In preservative, the dorsum varies from pale creamy tan to pale brown with scattered brown markings on the side of the head, supra- tympanic fold, and top of head. In some indi- viduals, faint transverse bands are evident on the dorsal surfaces of the hind limbs. The venter is uniform creamy white, except for a small amount of pigmentation on the ventral surfaces of the feet. Tadpoles: The tadpoles of Hyla picadoi are unknown; possibly they develop in brome- liads. Mating Call: No recordings of the call of this species have been obtained; further- more, the call has not been identified definitely in the field. Natural History: Hyla picadoi is an in- habitant of humid upper montane forests, where the species usually is associated with the bromeliads. Dunn (1937, p. 164) noted that the five specimens available at the time he described the species were all taken from bromeliads on Volean Barba, Costa Rica. Nine specimens obtained in Costa Rica by J. M. Savage and Norman Scott were all taken from bromeliads; five were obtained in March, and one each in February, June, July, and Decem- ber. I obtained three individuals from the Rio Poasito on Volean Poas, Alajuela Province, Costa Rica; one was found on March 21, 1961, and two were obtained on April 17, 1961. All were found on low vegetation near a rocky stream at night. Two individuals were ob- tained at an elevation of 1920 meters on the north slope of Cerro Pando, Bocas del Toro Province, Panama, in May, 1966. One juvenile was on a rock in a stream at night, and an adult female was on a bush near the stream at night. Because individuals were found on vege- tation along the streams at night, I suspected that the tadpoles of Hyla picadoi probably develop in the stream. Repeated search of the stream along which the frogs had been 1970 DUELLMAN: HYLID FROGS 323 85° 83° \ /~vV>-^ i \ ■V V \ I - 1° • H. picadoi O H. zeteki o \ • \ o • o \ • •b i 9° oj r ~^ ( D 0 50 100 ( / r X ( v\ 1 ^ ^U KILOMETERS i 85c 8 3° Fig. 151. Distribution of Hyla picadoi and Hijla zeteki. found failed to reveal tadpoles that were as- signable to Hyla picadoi, although tadpoles of the other species of hylids known along the stream were found. Consequently, it does seem probable that tadpoles of Hyla picadoi, like those of the related Hyla zeteki, develop in bromeliads. Remarks: The significance of the paired denticles on the lower jaw is unknown. This is a unique character in Hyla picadoi, and is unknown in any other Middle American hylid. Etymology: The specific name is a patro- nym for C. Picado T., the late Costa Rican naturalist, who contributed greatly to our knowledge of the bromeliad fauna and poison- ous snakes of Costa Rica. Distribution: Hyla picadoi occurs at high elevations (1900 and 2510 meters) in the Cor- dillera Central and Cordillera de Talamanca in Costa Rica and extreme western Panama (fig. 151). This species occurs at higher ele- vations than its relative Hyla zeteki. See Appendix 1 for the locality records of the 23 specimens examined. Hyla zeteki Gaige Hyla zeteki Gaige, 1929, p. 4 [holotype, U.M.M.Z. No. 63875 from Caldera Valley, above Boquete, Chiriqui Province, Panama; Helen T. Gaige collector]. Taylor, 1952c, p. 876. Diagnosis: This small species has a broad head with a heavy muscular development in the temporal region, vestigial webbing on the hands, the toes only about half webbed, granu- lar skin above the insertion of the arm, and 324 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 the anal opening surrounded by granules; the tympanum usually is partially concealed. The above combination of characters, plus the general yellowish tan color, will distin- guish Hyla zeteki from all other Middle American hylids, except H. picadoi. The latter is larger ( males to 32.8 mm. and only to 23.5 mm. in zeteki) and has two denticles instead of one, at the symphysis of the lower jaw. Furthermore, picadoi usually has dark pig- ment on the lips, loreal region, and supra- tympanic fold, whereas only the lips are pig- mented in zeteki. Description: Males of this small species attain a maximum snout-vent length of 23.5 mm., and females reach 26.2 mm. In three adult males from the highlands of Costa Rica and western Panama, the snout-vent length is 21.3 to 23.5 (mean, 22.5) mm.; the ratio of tibia length to snout-vent length is 0.502 to 0.545 (mean, 0.530); the ratio of foot length to snout-vent length is 0.423 to 0.455 (mean, 0.435); the ratio of head length to snout- vent length is 0.308 to 0.352 (mean, 0.329); the ratio of head width to snout-vent length is 0.339 to 0.362 (mean, 0.352), and the ratio of the diameter of the tympanum to that of the eye is 0.300 to 0.393 (mean, 0.346). In six females from the same region, the snout-vent length is 24.1 to 26.2 (mean, 25.4). The fe- males do not differ significantly from the males in proportions, except that the tym- panum is proportionately larger in females. The ratio of the diameter of the tympanum to that of the eye is 0.323 to 0.347 (mean, 0.395). The head is wider than the body, and the top of the head is flat. The eyes are large and prominent. The snout is broadly rounded in dorsal profile and truncate in lateral profile. The snout is short; the nostrils are barely pro- tuberant at a point about four-fifths of the distance from the eyes to the tip of the snout. The temporal region of the head is somewhat expanded. A moderately heavy dermal fold extends posteriorly from the eye, above the tympanum, and downward toward the point of insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is barely discernible and separated from the eye by a distance equal to about three times the diameter of the tympanum. The arms are moderately long and robust; the axillary membrane is absent. There is no row of tubercles on the ventrolateral edge of the forearm, but a distinct transverse dermal fold is present on the wrist. The fingers are moderately short and stout and bear moder- ately large discs; the width of the disc on the third finger is equal to half again the length of the tympanum. The subarticular tubercles are large and conical; the distal tubercle on the fourth finger and in some individuals on the third finger are bifid. The supernumerary tubercles are large, conical, and especially nu- merous on the proximal segments of each digit. A low, flat, bifid, palmar tubercle is present. In males the prepollex is greatly en- larged and bulbous, but does not bear nuptial excrescences. The fingers are no more than one-fourth webbed (fig. 150B). The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to the eye. A weak transverse dermal fold is present on the heel, and a weak tarsal fold extends the full length of the tarsus. Three or four small, low tubercles are present proximally on the outer edge of the foot. The inner metatarsal tu- bercle is elongate and elliptical. An outer metatarsal tubercle, if present, is low and sub- conical. The toes are moderately long and slender and bear discs that are nearly as large as those on the fingers. The toes are no more than one-half webbed (fig. 150D). The web- bing is vestigial between the first and second toes, and extends from the base of the penulti- mate phalanx of the second to the base of the antepenultimate phalanx of the third, from the base of the penultimate phalanx of the third, to the base of the antepenultimate pha- lanx of the fourth, and on to the base of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly near the upper level of the thighs. A heavy, granular anal sheath is present, and a pair of large tubercles is present ventrolaterally on either side of the anal opening. The skin above the insertion of the arm is weakly granular. The skin on the belly, ventral sur- faces of the arms, and ventral surfaces of the thighs is strongly granular; elsewhere, the skin is smooth. The tongue is broadly ovoid, 1970 DUELLMAN: HYLID FROGS 325 emarginate, and barely free posteriorly. The dentigerous processes of the prevomers are narrowly separated, strongly posteromedially inclined elevations; anterolateral borders of the processes lie between the posterior edges of the small, round choanae. Males have three or four teeth on each process and a total of six to eight (mean, 7.0) prevomerine teeth; females have three to five teeth on each proc- ess and a total of seven to nine (mean, 8.0) prevomerine teeth. There is a single denticle at the symphysis of the lower jaw. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, and subgular. The general coloration of Hyla zeteki is uniform pale yellowish tan ( pi. 1, fig. 1 ) . I have not observed Hyla zeteki in life. Gaige (1929, p. 5) noted that specimens from Chiri- qui Province, Panama, were "golden tan above becoming iridescent on sides; yellowish white beneath. Iris brownish red. A slender red vertebral stripe and a narrow spectacle-like mark around each eye joining across the snout. In alcohol the red markings have faded and the animal has become a uniform grayish tan." She noted that in a series of 12 specimens the red marks were lacking on the heads in some individuals, but that there was always a trace of red in the coloration. Taylor ( 1952c, p. 878) in describing a specimen from Isla Bo- nita, Heredia Province, Costa Rica, noted: "The specimen differs but little in color and marking from the type description. No me- dium red streak was present or red in the other coloration. The black 'spectacle-like' markings around eyes meeting medially are not clearly defined; the eye is distinctly long- er than the snout; the toe discs are smaller than finger discs." Taylor noted that the Costa Rican specimens of Hyla zeteki referred to by Dunn (1937, pp. 164-167) differ from the type in the absence of the red dorsal marks as well as the peculiar head markings. Color notes taken by Dr. J. M. Savage on a specimen (U.S.C. No. 510) from La Palma, San Jose Province, Costa Rica, are as follows: "Back, arms, legs uniform straw color. Head brownish. Venter whitish. Eyes reddish brown. Undersurface of arms and legs yel- lowish. Dark line on wrist; brownish on knees. Brown line from tympanum posterior for a short distance." In preservative, the frogs are pale creamy tan with no distinctive markings other than a dark line on the wrist and in some specimens a narrow middorsal line anteriorly on the back. In some specimens, the supratympanic fold is lightly pigmented, and in others, espe- cially K.U. No. 36480, the edge of the upper lip is heavily pigmented. Tadpoles: Dunn (1937, p. 164) provided a brief description of a tadpole of Hyla zeteki; Starrett (1960a, p. 26) elaborated on Dunn's description and provided an illustration of the tadpole. The only known lot of tadpoles (A.N.S.P. No. 23822 — nine specimens) are now rather soft and faded. For the sake of completeness, I include here another descrip- tion of these same tadpoles. A typical tadpole in developmental stage 36 has a body length of 8.1 mm. and a total length of 21.4 mm. The body is depressed and guitar-shaped in dorsal view; the greatest depth of the body is about three-fifths of the greatest width. In dorsal profile, the snout is bluntly rounded; in lateral profile, it is acutely rounded below and interrupted by the mouth dorsally. The eyes are moderately small, not greatly separated medially, and directed dor- solaterally. The nostrils are barely protuber- ant and situated at a point nearly midway between the eye and the posterior border of the mouth. The opening of the sinistral spira- cle is directed posteriorly on the ventrolateral edge of the body at about midlength of the body. The anal tube is long and dextral. The caudal musculature is robust and extends to the tip of the pointed tail. The fins are shal- low, deepest posteriorly. The dorsal fin is absent on the anterior one-fourth of the tail (fig. 152). Dunn (1937, p. 165) commented on the coloration as follows: ". . . pigmentation of evenly spaced and relatively few melano- phores above; fewer and more irregularly- spaced below; pale gray with no markings, the white muscles and the color of viscera and foot completely predominated over the pig- mentation. . . ." The tadpoles are now pale creamy tan with minute dark flecks on the dorsum and caudal musculature; the fins are unmarked. 326 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 152. Tadpole of Hijla zctcki, A.N.S.P. No. 23822. x 5. The mouth is anterodorsal and relatively small; its greatest width is equal to about one- third of the greatest width of the body. The mouth is completely bordered by an irregular row of small papillae; the lateral folds in the lips are absent. The beaks extend to the mar- gins of the lips; the lower beak is more mas- sive than the upper one. The upper beak is smooth and the lower beak is finely serrated. A single row of widely separated, short conical teeth is present above the beaks. A lower row is more or less continuous with the single upper row. Medial to the lower row is a secondary shorter row of widely separated teeth (fig. 153). Fig. 153. Mouth of tadpole of Hyla zeteki, A.N.S.P. No. 23822. x 30. Most of the nine specimens are too soft and distorted for accurate measurement. Dunn (1937, p. 165) grouped the tadpoles into four size-groups and noted that the relative length of the tail apparently decreased with age. Mating Call: The call of Hyla zeteki is unknown. Natural History: All known specimens of Hyla zeteki have been obtained from bromeliads in humid montane forests. Dunn ( 1937, p. 164 ) provided evidence that the species breeds in bromeliads. On June 7, 1936, near La Palma, San Jose Province, Costa Rica, he obtained eggs, tadpoles, and adults from bromeliads. The eggs were found on the out- side of the leaves above the level of the water. Dunn noted that two eggs were together on the same leaf and that three eggs in another plant were on three separate leaves. The tad- poles were found between the leaves, in the water, but not in the central core of the bromeliads. The stomachs of tadpoles con- tained only frog eggs. Dunn (1937, p. 166) inferred: "The observed disposition of the five eggs may indicate that Hyla zeteki lays its eggs out of water and moves about during oviposition. The stomach contents of the tad- poles may indicate that eggs of its own species furnish the major source of food supply for the tadpoles; the peculiarity of the mouthparts, jaw muscles, and digestive tract may reflect peculiarities of the feeding habits and the food; the reduction of gill filaments may indi- cate a difference in respiration from more normal hylid tadpoles; the reduction of fin and the progressive reduction of tail lengths may reflect the confined nature of the swim- ming space." Taylor ( 1958, p. 21 ) noted that a female (K.U. No. 36942) from Varablanca, Cartago Province, Costa Rica, contained numerous, pigmented eggs. Examination of this speci- men reveals the presence of 24 large eggs. The number of eggs in this gravid female tends to support Dunn's contention that the females may move about during oviposition. Remarks: Both Dunn (1937, p. 165) and Taylor (1952c, p. 878) noted the absence of red markings in Costa Rican specimens, as compared with those from the type locality in western Panama (Gaige, 1929, p. 5). The lack of sufficient fresh material precludes any assessment of this apparent geographic varia- tion. Etymology: The specific name is a patro- nym for James Zetek, the former resident- director of Barro Colorado Island in Panama. Distribution: Hyla zeteki occurs at ele- vations between 1200 and 1800 meters in hu- mid montane forests from central Costa Rica 1970 DUELLMAN: HYLID FROGS 327 to western Panama (fig. 151). The Costa Riean localities are on the Caribbean slopes, whereas the single Panamanian locality for this species is on the Pacific slopes near the Continental Divide. See Appendix 1 for the locality records of the 27 specimens examined. The Hyla bogotensis Group Definition: The frogs comprising this group are medium sized stream-breeders; males attain a snout-vent length of 41.8 mm. and females, 48.1 mm. The dorsum is pale green or tan with minute dark flecks or fine reticulations; in some species a pale yellow dorsolateral stripe begins on the canthus and extends to a point above the insertion of the arm. The palpebral membrane is clear; the tympanum is weakly defined or covered. The fingers are about one-third webbed, and the toes are about four-fifths webbed. The tarsal fold is weak, and an axillary membrane is ab- sent. Dermal fringes and appendages are absent on the limbs. A distinct "mental gland" is present on the chin in males (fig. 154), which have a single, median, subgular vocal sac but lack horny nuptial excrescences on the prepollices. The cranial elements are weakly ossified; a large, key-hole-shaped frontoparie- tal fontanelle is present. The sphenethmoid is broad but not ossified anteriorly between the nasals, which are wide, have small maxil- lary processes, barely overlap the spheneth- moid, but are separated medially (fig. 155). The quadratojugal is present. The squamosal is in bony contact with the crista parotica; the anterior arm of the squamosal extends about half of the distance to the maxillary. The medial ramus of the pterygoid does not have a bony articulation with the prootic. The prevomers are only moderately ossified and do not articulate anteriorly; the prevo- merine teeth are on anteromedially inclined processes. The tadpoles have moderately long muscular tails and large ventral mouths with six upper and nine lower rows of teeth. The mating call consists of long series of cricket- like chirps. The number of chromosomes is unknown. Composition: Four species are currently recognized in this group, which occurs at moderate to high elevations from Costa Rica to Venezuela and Ecuador. Twelve preserved frogs, one skeleton, and three lots of tadpoles have been examined from Middle America. Comments: Hyla colymba is unique among Middle American hylids by having a "mental gland"; furthermore, it is the only species in lower Central America having stream-adapted tadpoles with a multiplicity of tooth rows. Other species having these Fig. 154. Ventral view of throat of Hyla colymba, K.U. No. 95979, showing mental gland. X 5. Fig. 155. Dorsal view ot skull of tit/la colymba, K.U. No. 31865. x 5. 328 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 characters are high-elevation species in the northern Andes — H. bogotensis (Peters) in Colombia and H. jahni Rivero and H. para- mica Rivero in Venezuela. I have examined the types of all of these nominal species and have examined the sacral diapophyses. The diapophyses are expanded in all, including the type of Hyla bogotensis, which Peters ( 1882a) stated as having rounded diapophyses, a char- acter that he used to erect the genus Hijlo- nomus (=Hyloscirtus Peters, 1882b). Hyla colymba Dunn Hyla colymba Dunn, 1931a, p. 400 [holotype, M.C.Z. No. 10234 from La Loma, Bocas del Toro Province, Panama; Chester Duryea and Emmett R. Dunn collectors], Duellman, 1966b, p. 267 [synony- mized Hyla alvaradoi Taylor, 1952c with Hyla colym- ba Dunn, 1931], Hyla alvaradoi Taylor, 1952c, p. 882 [holotype, K.U. No. 30886 from Moravia, Cartago Province, Costa Rica; Edward H. Taylor collector]. Diagnosis : This moderately small, stream- breeding frog is usually pale green above (capable of changing to pale brown) and bluish green below. A faint creamy yellow line is present on the canthus, edge of upper eyelid, and on the supratympanic fold. In preservative, the dorsum is pale cream with minute dark flecks. The presence of a mental gland immediately distinguishes this frog from all other Middle American hylids. The only other species having similar markings is Hyla angustilineata, the juveniles of which have a bright green dorsum, dark brown flanks, and a narrow creamy white dorsolateral line ex- tending to the groin. Description: Males of this moderately small species attain a maximum snout-vent length of 37.0 mm., and females reach 43.3 mm. In six males from Costa Rica and Pan- ama, the snout- vent length is 31.9 to 37.0 (mean, 34.7) mm.; the ratio of tibia length to snout-vent length is 0.452 to 0.500 (mean, 0.472 ) ; the ratio of foot length to snout-vent length is 0.387 to 0.455 (mean, 0.409); the ratio of head length to snout-vent length is 0.302 to 0.325 (mean, 0.316), and the ratio of the diameter of the tympanum to that of the eye is 0.421 to 0.545 (mean, 0.489). Three females from the same area have snout-vent lengths of 31.4 to 39.1 (mean, 36.2) mm. Measurements and proportions of seven males and five females from Tandapi, Pichincha Prov- ince, Ecuador, reveal no significant differences from the Central American sample, except that the females are noticeably larger. The five females have snout-vent lengths of 36.7 to 43.3 (mean, 40.8) mm. The head is as wide as the body, and the top of the head is flat. The eyes are relatively small and not prominent. In dorsal profile, the snout is acutely rounded; in lateral profile, it is bluntly rounded. The snout is moderately long and shallow; the nostrils are barely pro- tuberant and situated at a point about three- fourths of the distance from the eyes to the tip of the snout. The canthus is angular, and the loreal region is noticeably concave; the lips are moderately thick and barely flared. A moderately heavy dermal fold extends pos- teriorly from the eye, above the tympanum, and to a point above the insertion of the arm. The fold obscures the upper edge of the tym- panum, which otherwise is only barely distinct and separated from the eye by a distance equal to the diameter of the tympanum. The arms are moderately long and robust; an axillary membrane is absent. There are no tubercles on the ventrolateral edge of the forearm, but a transverse dermal fold is pres- ent on the wrist. The fingers are moderately short and robust and bear rather small discs; the width of the disc on the third finger is about equal to the diameter of the tympanum. The subarticular tubercles are rather small, round, and elevated; the distal tubercle on the fourth finger is bifid in some individuals. Supernumerary tubercles are lacking; instead, there is a fleshy longitudinal ridge on the proximal segment of each digit. A small, conical palmar tubercle is present. In males, the prepollex is greatly enlarged into an oval structure with a sharp leading edge. The fingers are about one-third webbed (fig. 156A). The webbing is vestigial between the first and second fingers, and extends from the base of the antepenultimate phalanx of the third, from the middle of the antepenultimate phalanx of the third to the base of the penul- timate phalanx of the fourth finger. The hind limbs are rather short and robust; the heels of the adpressed limbs overlap by about one- sixth of the length of the shank. The tibio- tarsal articulation extends to the tympanum 1970 DUELLMAN: HYLID FROGS 329 or to the posterior edge of the eye. A thin transverse dermal fold is present on the heel, and a low tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is low, flat, elliptical, and broadly visible from above. An outer metatarsal tubercle is lacking. The toes are moderately short and slender and bear small discs that are barely wider than the penultimate phalanges. The Fig. 156. Hand (A) and foot (B) of Hula cohjmba, K.U. No. 95979. X 5. subarticular tubercles are moderately small and subcorneal; faint supernumerary tubercles are present distally on some digits, but they are absent proximally. The toes are about four-fifths webbed (fig. 156B). The webbing extends from the middle of the penultimate phalanx of the first toe to the middle of the penultimate phalanx of the second, from the base of the disc of the second to the distal end of the penultimate phalanx of the third, from the base of the disc of the third to the base of the penultimate phalanx of the fourth, from the middle of the penultimate phalanx of the fourth to the base of the disc of the fifth toe. The anal opening is directed posteroven- trally near the midlevel of the thighs. A short anal sheath is present; two vertical folds are present on either side of the anal opening. The skin on the proximal ventral surfaces of the thighs is weakly granular; in some indi- viduals, weak granules are evident on the belly; elsewhere, the skin is smooth. An ovoid "mental gland" is present anteriorly on the chin. All specimens, save one, have this gland. The tongue is elongately ovoid, mar- ginate, and not free posteriorly. The dentiger- ous processes of the prevomers are elongate, narrowly separated, anteromedially inclined elevations between the posterior margins of the moderately small, elliptical choanae. In- dividuals of both sexes have five to eight teeth on each process and a total of 11 to 15 (mean, 13.2) prevomerine teeth. The vocal slits ex- tend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately dis- tensible. The general coloration of Hyla cohjmba is pale green with a faint yellow stripe on the edge of the upper eyelid and on the supra- tympanic fold (pi. 52, fig. 2). Most individ- uals when found at night are pale green above with faint yellow flecks or scattered brown dots. A pale yellow stripe begins on the can- thus just . anterior to the eye or on the edge of the upper eyelid and extends posteriorly along the supratympanic fold usually to a point just above the insertion of the arm. A faint yellow transverse anal stripe is present. In some individuals, a faint creamy yellow line is present on the outer edge of the fore- 330 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 arm and on the outer edge of the toot. The ventral surfaces of the limbs are pale green, and the throat is pale bluish green. The belly and chest are white, and the mental gland is white or creamy yellow. The bones appear pale green through the skin and flesh. The iris is pale brown. One individual from Laguna, Darien Prov- ince, Panama, was yellowish tan with brown flecks above; the limbs were colored like the dorsum, except that the thighs and upper arms were slightly paler. The anterior part of the head was brown. The mental gland was yellow with brown flecks. In preservative, the dorsum varies from pale creamy white to creamy tan or pale brown. The short dorsolateral stripes are evi- dent and white. The venter is creamy white. Minute dark flecks are present on the dorsum in many individuals; usually these are most evident on the head and middorsally on the body. Tadpoles: A typical tadpole in develop- mental stage 25 has a body length of 15.1 mm. and a total length of 37.3 mm. The body is elongately ovoid, slightly wider than deep. In dorsal profile, the snout is round; in lateral profile, it is acutely rounded. The eyes are small, widely separated, and directed dorso- laterally. The nostrils are situated about mid- way between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posteriorly at a point below the mid- line and at about midlength of the body. The anal tube is long and dextral. The caudal musculature is robust and terminates just short of the pointed tail. The fins are moder- ately shallow; at midlength of the tail, the depth of the caudal musculature is greater than the depth of either fin. The dorsal fin does not extend onto the body (fig. 157). The dorsum of the body is bronze-tan with golden lichenous flecks. The sides of the body are dark brown with gold flecks. The caudal musculature is tan with dark brown spots; small brown spots are present on the dorsal fin but absent on the ventral fin. The iris is dull bronze. In preservative, the body is brown with faint white flecks. The caudal musculature is creamy tan; brown flecks are present on the musculature and the dorsal fin. The mouth is ventral and large; its width is equal to about two-thirds of the greatest width of the body. The mouth is completely bordered by two rows of small papillae; deep lateral folds are present in the lips. The beaks are moderately slender and bear rather long, blunt serrations. The upper beak is in the form of a broad arch with long slender lateral processes; the lower beak is broadly V-shaped. There are six upper and nine lower rows of teeth. The sixth upper and first lower rows are narrowly interrupted medially; the other rows are complete. All of the rows are long and extend to the margins of the lip; the three outermost lower rows are somewhat shorter than the others (fig. 158). ^"mrm^ Fig. 158. Mouth of tadpole of Hijlti colymba, K.U. No. 116779. x 15. w^~"- ;.'/; •*p-TT"r'T""7 ■•' ' - •.'-..-' -"''^'^T1^ Fie. 157. Tadpole of Hijla colymba, K.U. No. 116779. x 6. 1970 DUELLMAN: HYLID FROGS 331 The only noticeable variation in the tad- poles of this species is in the number of rows of teeth. In some individuals, a faint seventh upper row is evident; some specimens have only seven or eight lower rows, and one has a short tenth row. The tadpoles of this species were first de- scribed by Dunn (1924, p. 3) as Hyla albo- marginata; Dunn (1931a, p. 400) later as- signed these tadpoles to Hyla cohjmba. Mating Call: The call of Hyla cohjmba consists of a series of short, high-pitched, cricket-like chirps. Notes are produced rap- idly; the call rate varies from 123 to 236 (mean, 179) notes per minute. There are 12 to 104 notes in each of ten call groups; the interval between call groups varies from one to three seconds. The duration of each note is approximately 0.05 of a second. The funda- mental frequency is at about 1800 cycles per second, and the dominant frequency is at about 3600 cycles per second; usually two harmonics above the dominant frequency are evident (pi. 23, fig. 2). Natural History: Hyla cohjmba inhabits cloud forests or humid lower montane forests, where the frogs have been found only along the streams. Males call from beneath large boulders in small streams. Even in such con- cealed calling sites, they are extremely wary; at the slightest disturbance, they will cease calling for several minutes. One individual was found on the leaves of a bromeliad at night on Cerro Cituro in the Serrania de Pine, Darien Province, Panama. Taylor ( 1952c, p. 885) noted that a specimen was found on a green plant growing on the edge of a small forest rivulet at Moravia, Cartago Province, Costa Rica. Calling males have been found in the months of April, July, and December. Tadpoles have been observed in quiet pools in small rocky streams. Dunn ( 1924, p. 4 ) noted that he found tadpoles of this species clinging to rocks over which a swift current of water was streaming. Recently metamorphosed young have been found in April and May; two individuals hav- ing completely resorbed tails have snout-vent lengths of 16.9 and 18.7 mm. The juveniles are colored like the adults, except that the hands and feet are yellow. Charles W. Myers observed that the dorsum in juveniles from Darien Province was sometimes heavily flecked with dark pigment, but at other times this pigment was not visible or was concen- trated in small areas. Dunn ( 1924, p. 3 ) thought that he might have found the eggs of this species, which he discussed under the name of Hyla albomargi- nata; he stated: "A foamy mass of eggs was found under a rock in the small stream. As this was the situation from which Hyla albo- marginata was calling, it is quite possible, by association and by elimination of the other three species whose tadpoles inhabited the stream, that these were the eggs of this ani- mal." Dunn also found eggs attached to a leaf overhanging the stream. He thought that these were the eggs of Hyla uranochroa, but since no proof of identity of either clutch of eggs was available, the specific assignment is impossible. Remarks: Dunn ( 1924, p. 3) first obtained this species in the summer of 1923. At that time, he erroneously associated the specimens with Hyla albomarginata. He obtained his material at La Loma, Bocas del Toro Province, Panama. Later Dunn (1931a, p. 400) realized his previously incorrect assignment and named the frogs from La Loma as Hyla cohjmba. Dunn did not mention the mental gland in his description of the species. Taylor ( 1952c, p. 882) named Hyla alvaradoi on the basis of a single adult male from Moravia, Cartago Prov- ince, Costa Rica; he gave a detailed descrip- tion of the holotype and noted the circular mental gland, but he did not compare Hyla alvaradoi with cohjmba. Duellman ( 1966b, p. 267) compared the holotypes of the two species and noted that alvaradoi was the same as cohjmba. In the summer of 1967, a series of adults, juveniles, and tadpoles of this species were obtained at Tandapi, on the Pacific slopes of Ecuador by John D. Lynch. In all essential characters, the adults and larvae from Ecua- dor are the same as those from Central Amer- ica. Cochran and Goin (1970) did not record this species from Colombia. Etymology: The specific name is derived from the Greek kolymbos, meaning swimmer, and apparently was used in reference to the stream-adapted tadpoles. Distribution: Hyla cohjmba inhabits 332 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 159. Distribution of Hyla colymba. cloud forests and lower humid montane forests at elevations between 600 and 1400 meters on the Caribbean slopes of Costa Rica and west- ern Panama and on the Pacific slopes of east- ern Panama (fig. 159). This species also is known from the Pacific slopes of Ecuador and presumably occurs in Colombia. See Appendix 1 for the locality records of the 16 specimens examined. The Hyla salvadorensis Group Definition: Members of this group are moderately small stream-breeding species; males attain a maximum snout-vent length of 36.7 mm. and known females, 37.0 mm. The dorsum is dark brown or olive-green without transverse bands on the limbs. The iris is reddish bronze or red, and the palpebral mem- brane is clear. The hands and feet are large; the hands are about one-half and the feet are about three-fourths webbed. A distinct tarsal fold is present, but an axillary membrane and dermal folds or appendages on the limbs are lacking. Males have single, median, subgular vocal sacs and horny nuptial excrescences on the prepollices. The skull is moderately ossi- fied. A large frontoparietal fontanelle is pres- ent. The sphenethmoid extends anteriorly be- tween the nasals, which are moderately slen- der, widely separated medially, and sutured to the sphenethmoid (salvadorensis) or over- lap the sphenethmoid (legleri). The squa- mosal is in bony contact with the crista parotica (salvadorensis) or not (legleri), and the anterior arm of the squamosal extends one-third of the distance to the maxillary (fig. 160). The quadratojugal is present, and the prevomers are moderately well ossified and bear teeth. The medial ramus of the Fig. 160. Dorsal view of the skull of Hyla salva- dorensis, K.U. No. 103033. x 6. 1970 DUELLMAN: HYLID FROGS 333 pterygoid is in bony contact with the prootic. The tadpoles have long muscular tails and ventral mouths with two or three upper and five lower rows of teeth. The mating calls consist of a single long, or a series of short, poorly modulated notes. The haploid number of chromosomes is 12. Composition: Two species (Hyla legleri and salvadorensis) comprise the group, which occurs at moderate elevations on the Pacific slopes from El Salvador to western Panama. Eighty-one preserved frogs, five skeletons, and nine lots of tadpoles have been examined. Comments: Hyla legleri, formerly associ- ated with the Hyla uranochroa group because of its red eyes, seems to be more closely allied to Hyla salvadorensis. Members of the Hyla uranochroa group have noticeably different skulls and tadpoles from those of legleri, which are like those of salvadorensis. In frogs of the Hyla uranochroa group, the bright red color of the iris develops early in larval development ( present in developmental stage 25). The same is true of Hyla cryihrom- ma in Mexico. In Hyla legleri the iris in the young tadpoles is deep bronze, and the red pigment is not apparent until developmental stage 38 or 39; the red pigment does not fully develop in salvadorensis. The two species in this group inhabit mon- tane areas and probably represent relicts of a former population that was widespread from Costa Rica northward across the Nicaraguan gap to the highlands of Nuclear Central America (highlands of Chiapas, Guatemala, and Honduras). Hyla legleri Taylor Hyla legleri Taylor, 1958, p. 33 [holotype, K.U. No. 32932 from 15 kilometers west-southwest of San Isidro el General, San Jose Province, Costa Rica; Ed- ward H. Taylor collector]. Diagnosis: This moderately small species has a dark reddish brown or olive-green dor- sum, a white lateral stripe, a distinct white anal stripe, white stripes along the outer edges of the forearms and feet, a red eye, and a dark gray vocal sac in breeding males. It differs from its close relative, Hyla salvadorensis, by having smaller discs and pale brown or yel- lowish tan, instead of dark brown, on the posterior surfaces of the thighs. Furthermore, salvadorensis has a coppery-bronze colored eye and lacks well-defined white stripes. Hyla uranochroa and rufioculis, both of which have red eyes, differ from legleri by being smaller and by having more truncate snouts, less webbing, pale throats in breeding males and a distinct white labial stripe. The other red- eyed Middle American species, erythromma, differs by having a pale green dorsum and a faintly reticulated palpebral membrane. Description: Males of this moderately small species attain a maximum snout-vent length of 36.7 mm., and females reach 37.0 mm. In a series of 18 males from the Pacific slopes of Costa Rica, the snout-vent length is 31.7 to 36.7 (mean, 33.5) mm.; the ratio of tibia length to snout-vent length is 0.462 to 0.509 (mean, 0.485); the ratio of foot length to snout-vent length is 0.407 to 0.443 (mean, 0.425); the ratio of head length to snout- vent length is 0.307 to 0.360 (mean, 0.339); the ratio of head width to snout-vent length is 0.312 to 0.358 (mean, 0.343), and the ratio of the diameter of the tympanum to that of the eye is 0.459 to 0.618 (mean, 0.534). Three females from the same areas have snout-vent lengths of 36.0 to 37.0 (mean, 36.5) mm. and do not differ significantly in proportions from the males. The head is as wide as the body, and the top of the head is barely convex. In dorsal profile, the snout is acutely rounded; in lateral profile, it is rounded above and terminally truncate. The snout is moderately long; the nostrils are barely protuberant at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is weakly angular; the loreal region is flat, barely in- clined, and the lips are moderately thick and barely flared. A heavy dermal fold extends posteriorly from the eye, above the tympanum, to a point above the insertion of the arm. The fold obscures the upper edge of the tym- panum, which otherwise is distinct and sepa- rated from the eye by a distance slightly less than the diameter of the tympanum. The arms are moderately short and robust. An axillary membrane is absent. A row of tu- bercles, which in some specimens are fused into a low, thick dermal fold, extends the length of the ventrolateral edge of the fore- arm; a weak transverse dermal fold is present 334 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 161. Hands and feet of members of the Hi/la salvadorensis group. A and C. Hijla legleri, K.U. No. 103685. B and D. Hijla salvadorensis, K.U. No. 103256. X 5. on the wrist. The fingers are rather short and stout and bear large discs; the width of the disc on the third finger is equal to the diameter of the eye. The subarticular tubercles are large and round; in a few specimens, the distal tubercle on the fourth finger is weakly bifid. The supernumerary tubercles are low and indistinct. A low, bifid palmar tubercle is present. The prepollex is moderately en- larged and in breeding males bears a horny nuptial excrescence. The fingers are about one-half webbed (fig. 161A). The webbing is 1970 DUELLMAN: HYLID FROGS 335 vestigial between the first and second fingers and extends from the base of the penultimate phalanx of the second to the distal end of the antepenultimate phalanx of the third and on to the middle of the penultimate phalanx of the fourth finger. The hind limbs are mod- erately short and robust; the heels of the ad- pressed limbs overlap by about one-fifth of the length of the shank. The tibiotarsal articula- tion extends to the middle of the eye. A weak dermal fold is present on the heel, and a low tarsal fold is present on the distal half of the tarsus. The inner metatarsal tubercle is low, flat, ovoid, and barely visible from above. No distinct outer metatarsal tubercle is pres- ent. The toes are moderately long and stout and bear discs that are slightly smaller than those on the fingers. The subarticular tuber- cles are moderately large and round, and the supernumerary tubercles are low and indis- tinct. The feet are about three-fourths webbed (fig. 161C). The webbing extends from the distal end of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the base of the disc of the second to the base of the penultimate phalanx of the third, from the distal end of the penul- timate phalanx of the third to the base of the penultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. A short, broad anal sheath is present, and numerous small tubercles are present below the anal opening. The skin on the throat, belly, and proximal posteroventral surfaces of the thighs is granu- lar; elsewhere, the skin is smooth. The tongue is broadly cordiform, shallowly notched be- hind, barely notched anteriorly in some speci- mens, and not free posteriorly. The dentiger- ous processes of the prevomers are small trans- verse elevations between the moderately small, ovoid choanae. Males have three or four (mean, 3.6) teeth on each process, and fe- males have four or five (mean, 4.7) teeth on each process. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla legleri is dark brown above and creamv white below (pi. 54, fig. 5). The dorsum usually is some shade of brown, either olive-brown or dull reddish brown. In some individuals, darker reticulations of olive-brown or reddish brown are visible on the dorsum. A creamy yellow stripe extends the length of the flank and is not continuous with a thin white stripe on the upper lip, which is absent in some specimens. The anterior and posterior surfaces of the thighs are orange-brown to yellowish tan. There are no transverse bands on the limbs. A distinct white stripe is present above the anal opening and on the ventrolateral edges of the forearms and feet. The posterior sur- face of the upper arm proximally is white. The belly is creamy white, and the throat in breeding males is dark gray. The iris is red. In preservative, the dorsum varies from dull reddish brown to dark brown. The an- terior and posterior surfaces of the thighs are pale reddish brown to creamy tan. The stripe on the lip, flanks, forearms, feet, and above the anus are creamy white. Usually the tu- bercles below the anal opening are tipped with white. The ventral surfaces are creamy tan, except the throat, which is dark gray or heavily suffused with brown in breeding males. Tadpoles: A developmental series of tad- poles is available from 15 kilometers west- southwest of San Isidro el General, San Jose Province, Costa Rica (table 36). A typical tadpole in developmental stage 36 has a body length of 14.0 mm. and a total length of 41.0 mm. The body is ovoid, widest anteriorly, and somewhat wider than deep. In dorsal profile, the snout is bluntly rounded, and in lateral profile, it is acutely rounded. The eyes are large, widely separated, and directed dorso- laterally. The nostrils are directed anterolat- eral!}' at a point about midway between the eyes and the tip of the snout. The sinistral spiracle is rather small and situated below the midline at about midlength of the body. The anal tube is short and dextral. The caudal musculature is robust and extends nearly to the tip of the rounded tail. The fins are rela- tively low, and the dorsal fin does not extend on to the body. At midlength of the tail, the depth of the caudal musculature is greater than the depth of either the dorsal or ventral fins (fig. 162A). 336 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 ^ t't '- >'.» V-"-'""" .-, '1:^:V:i Fig. 104138. 162. Tadpoles of members of the Hi/la salvadorensis group. B. Hyla salvadorensis, K.U. No. 68497. X 3. A. Hyla legleri, K.U. No. The body and tail are pale tan with dark brown flecks and spots; the latter tend to form transverse bands on the dorsal surface of the tail. The venter is creamy white. The iris is bronze in earlier developmental stages; in stage 38 or 39, the iris begins taking on a reddish appearance. In preservative, the body and tail are pale creamy tan with brown flecks and blotches. Few, if any, flecks are present on the ventral fin. The mouth is ventral and moderately large; its width is equal to slightly more than the greatest width of the body. Deep lateral folds are present in the lips which are completely bordered by two rows of small papillae; addi- tional papillae are present in the lateral folds. The beaks are moderately well developed and bear short, blunt serrations. The upper beak is in the form of a broad arch with moderately robust lateral processes; the lower beak is broadly V-shaped. There are two or three upper rows of teeth and five lower rows. The third upper row, when present, is composed of small teeth arranged in a fragmented row at the inner edge of the papillae. The first, and sometimes the second upper row is nar- rowly interrupted medially. The lower rows are complete and nearly as long as the upper rows (fig. 163A). Mating Call: The call of Hyla legleri consists of a single, moderately long, poorly modulated note. An analysis of eight record- ings reveals that the note repetition rate varies from eight to 32 (mean, 14) notes per minute. The duration of each note is 0.23 to 0.40 (mean, 0.29) of a second, and the pulse rate is 89 to 125 (mean, 108) pulses per second. The fundamental frequency varies from 83 to 230 (mean, 149) cycles per second. Two frequencies usually are emphasized. The low- TABLE 36 Measurements of Tadpoles of Hyla legleri, with Means in Parentheses, in Relation to Developmental Stages. Stage N Body Length Tail Length Total Length 25 . .. 13 6.5-11.9 (9.24) 26 2 10.9-11.8 (11.3) 28 2 10.9-12.6 (11.8) 30 3 12.6-13.2 (12.8) 31 3 12.8-13.7 (13.2) 36 .. 5 13.0-14.9 (13.9) 40 .. 4 13.2-14.5 (14.1) 42 3 14.3-14.6 (14.5) 46 4 14.6-18.1 (15.9) 11.5-24.8 18.9-21.8 23.3-27.0 24.1-28.1 24.9-28.3 26.8-30.2 27.8-32.0 28.2-31.2 (16.9) (20.4) (25.2) (25.9) (26.2) (28.7) (30.9) (28.9) 18.0-36.2 29.8-33.6 34.2-39.6 36.8-40.7 37.7-42.0 40.2-44.9 41.0-44.9 42.5-45.8 (26.2) (31.7) (36.9) (38.7) (39.4) (42.7) (44.8) (43.4) 1970 DUELLMAN: HYLID FROGS 337 Fig. 163. Mouths of tadpoles of the Hyla salva- dorensis group. A. Hyla legleri, K.U. No. 10-1138. B. Hyla salvadorensis, K.U. No. 68497. X 12. er of these is between 1036 and 1427 (mean, 1274) cycles per second, whereas the upper is between 2036 and 2745 (mean, 2397) cycles per second (pi. 22, fig. 3). Natural History: Hyla legleri inhabits humid montane forests, where this species usually is found along small streams. Males have been heard calling from February through July. Males usually call from dense vegetation no more than 1 meter above the water. Some calling males have been found on rocks in the stream when these rocks are covered by dense vegetation. The tadpoles develop in shallow streams, where they live in those parts of the stream having a gravel bottom and subject to mod- erate currents. The coloration of the tadpoles blends well with the color of the stream bot- tom, so that the tadpoles are difficult to see. When disturbed, the tadpoles swim away to rest again on the bottom; they do not actually seek shelter beneath rocks or amidst debris in the stream. Recently metamorphosed young have been found in May and July. The young are dull olive-green above and white below. The white stripe and mark present in adults are obvious in the juveniles; in addition, the heels and elbows in juveniles are marked with white. These recently metamorphosed young have bright red eyes. Remarks: Taylor (1958, p. 37) in his de- scription of Hyla legleri suggested that the new species was related to Hyla nigripes Cope (=Smilisca sorclida Peters). Subsequent workers, such as Starrett (1966) and Duell- man (1966b) considered Hyla legleri to be allied with the other Costa Rican red-eyed species (Hyla rufioculis and uranochroa) . On the basis of the cranial osteology of the adult and the characteristics of the tadpoles, I now place Hyla legleri in close association with Hyla salvadorensis and consider that the spe- cies is not closely related to Hyla rufiocitlis and uranochroa. Etymology: The specific name is a patro- nym for Dr. John M. Legler, a former cura- torial assistant at the Museum of Natural History at the University of Kansas. Distribution: Hyla legleri occurs at ele- vations between 700 and 1600 meters on the Pacific slopes of the Cordillera de Talamanca in eastern Costa Rica and extreme western Panama (fig. 164). See Appendix 1 for the locality records of the 65 specimens examined. Hyla salvadorensis Mertens Hyla salvadorensis Mertens, 1952a, p. 169 [holo- type, S.N.M. No. 43045 from Hacienda San Jose, Sierra Metapan, Departamento Santa Ana, El Salva- dor; Robert Mertens collector]. Ptychohyla spinipollex (in part): Lynch and Fug- ler, 1965, p. 11. Diagnosis: This moderately small species has a dull brown dorsum and posterior sur- faces of the thighs, faint white stripes on the outer edges of the forearms and feet and above the anus, mottled flanks, a coppery bronze iris, and a dusky throat in breeding males. Hyla legleri differs by having a red eye, well-defined white stripes on the outer edges of the forearms and feet and above the anus, a white lateral stripe, and larger discs. Super- ficially, Hyla salvadorensis is similar to Pty- chohyla euihysanota and spinipollex; the lat- ter have bronze-colored eyes and in breeding males large ventrolateral glands and nuptial excrescences composed of spines, instead of 338 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 82° — r • H. legleri o H. salvadorensis 0 300 — i KILOMETERS Fig. 164. Distribution of Hijla legleri and Hyla salvadorensis. a horny pad. Furthermore, P. spinipollex has a vertical rostral keel and bold mottling on the flanks. Description: Males of this moderately small species attain a maximum snout-vent length of 35.9 mm.; adult females are un- known.s In a series of six males from Cerro Uyuca, Departamento Franciseo-Morazan, Honduras, the snout-vent length is 34.3 to 35.9 (mean, 34.9) mm.; the ratio of tibia length to snout-vent length is 0.471 to 0.520 (mean, s Dr. John R. Meyer obtained a gravid female having a snout-vent length of 41.1 mm. on June 28, 1968, at 14.4 kilometers east of Nueva Ocotepeque, Departamento de Ocotepeque, Honduras. 0.491 ) ; the ratio of foot length to snout- vent length is 0.390 to 0.410 (mean, 0.400); the ratio of head length to snout-vent length is 0.315 to 0.341 (mean, 0.330); the ratio of head width to snout-vent length is 0.319 to 0.353 (mean, 0.337), and the ratio of the diameter of the tympanum to that of the eye is 0.556 to 0.625 (mean, 0.590). Three males from the Pacific slope in El Salvador have snout- vent lengths of 30.5 to 31.6 (mean, 31.1) mm. and do not differ in proportions from the speci- mens from Cerro Uyuca. The head is as wide as the body, and the top of the head is barely convex. In dorsal profile, the snout is acutely rounded, and in 1970 DUELLMAN: HYLID FROGS 339 lateral profile, it is round. The snout is mod- erately long; the nostrils are barely protuber- ant at a point about three-fourths of the dis- tance from the eyes to the tip of the snout. The canthus is rounded; the loreal region is barely concave, and the lips are moderately thick and barely flared. A moderately heavy dermal fold extends posteriorly from the eye, above the tympanum, and on to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance slightly less than the diam- eter of the tympanum. The arms are moderately short and robust; an axillary membrane is absent. A row of low tubercles on the ventrolateral edge of the forearm is fused into a nearly continuous fold; a weak transverse dermal fold is present on the wrist. The fingers are moderately short and robust and bear medium-sized discs; the width of the disc on the third finger is equal to about two-thirds of the diameter of the tympanum. The subarticular tubercles are moderately large and round; the distal tuber- cle on the fourth finger is weakly bifid in some specimens. The supernumerary tubercles are low and indistinct. The palmar tubercle is large, ovoid, and usually entire. The pre- polli-x is moderately enlarged and in breeding males bears a horny nuptial excrescence. The fingers are about one-third webbed (fig. 161B). The webbing is vestigial between the first and second fingers and extends from the base of the penultimate phalanx of the second to the middle of the antepenultimate phalanx of the third and from the distal end of the antepenultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are mod- erately short and robust. The heels of the adpressed limbs barely overlap. The tibio- tarsal articulation extends to the posterior corner of the eye. A transverse dermal fold is present on the heel, and a weak tarsal fold is present distally on the tarsus. The inner metatarsal tubercle is low, flat, ovoid, and not visible from above. The outer metatarsal tu- bercle is minute and conical. The toes are moderately short and stout and bear discs that are only slightly smaller than those on the fingers. The subarticular tubercles are moder- ately large and round and the supernumerary tubercles are low and indistinct. The toes are about two-thirds webbed (fig. 161D). The webbing extends from the middle of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the sec- ond, from the distal end of the penultimate phalanx of the second to the distal end of the antepenultimate phalanx of the third, from the middle of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth and on to the middle of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. A short, broad anal sheath is present, but tubercles are absent below the anal opening. The skin on the throat, belly, and ventral surfaces of the thighs is granular; elsewhere the skin is smooth. The tongue is broadly eordiform, shallowly notched posteriorly and barely, if at all, free behind. The dentigerous processes of the prevomers are small, widely separated, transverse ridges between the moderately large, ovoid choanae. Males have three to five (mean, 4.3) teeth on each process. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla salvadoren- si'.s is dull brown above and creamy white below (pi. 59, fig. 4). At night, specimens from Cerro Uyuca were pale olive-gray or pale tan with faint olive-brown markings above. By day, the dorsum changed to brown with darker brown markings with or without small yellow flecks. The anterior and posterior sur- faces of the thighs, the ventral surfaces of the legs, the first three toes, and the thumb are orange-brown. The chin and chest are white, and the belly is pale creamy yellow, becoming pale orange posteriorly. The flanks are mot- tled silvery white and dark brown. The edge of the chin is heavily flecked with dark brown in breeding males. There is a narrow white stripe on the upper lip, on the outer edge of the forearm and foot, and above the anus. The iris is a copper color with fine black flecks. Individuals from Rancho San Jose, Departamento Santa Ana, El Salvador, were dull green above with darker olive-green 340 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 markings. Otherwise, they were colored like those from Cerro Uyuea. In preservative the dorsum is dull brown with faint darker brown flecks and fine reticu- lations; there are no distinct transverse marks on the limbs. The anterior and posterior sur- faces of the thighs are pale brown or yellowish tan. The venter is pale creamy tan with gray- ish brown flecks on the periphery of the chin. The flanks are brown with white flecks or mottling. A thin, frequently interrupted, white stripe is present on the very edge of the upper lip. The white strip on the outer edges of the forearms and feet are narrow, but dis- tinct. In most specimens a narrow, but dis- tinct, white line is present above the anus. Tadpoles: A small series of tadpoles is available from Rancho San Jose, Departa- mento Santa Ana, El Salvador. Five tadpoles in developmental stage 25 have body lengths of 13.5 to 14.2 (mean, 13.9) mm. and total lengths of 39.5 to 42.3 (mean, 41.3) mm. Two tadpoles in developmental stage 38 each have a body length of 16.0 mm. and a total length of 48.0 mm. A typical tadpole in developmental stage 25 has a body length of 14.0 mm. and a total length of 42.0 mm. The body is ovoid, widest at midlength, and only slightly wider than deep. In dorsal profile, the snout is bluntly rounded, and in lateral profile it is round. The eyes are moderately large, widely separated, and directed dorsolaterally. The nostrils are directed anterolaterally at a point about mid- way between the eyes and the tip of the snout. The opening of the sinistral spiracle is di- rected posteriorly at a point just below the midline slightly posterior to the midlength of the body. The anal tube is short and dextral. The caudal musculature is robust and extends nearly to the tip of the rounded tail. The fins are low, and the dorsal fin does not extend onto the body. At midlength of the tail, the depth of the caudal musculature is much greater than the depth of either the dorsal or ventral fins (fig. 162B). In preservative, the body is dull brown; the caudal musculature is creamy tan and the caudal fins are transparent. The tail is marked by numerous interconnecting brown flecks and streaks. The mouth is ventral and moderately large; its width is equal to slightly more than one-half of the greatest width of the body. Deep lateral folds are present in the lips, which are completely bordered by two rows of small papillae; numerous additional pa- pillae are present in the lateral folds. The beaks are well developed and bear short, blunt serrations. The upper beak is in the form of a broad arch with moderately long, robust lateral processes. The ventral beak is broadly V-shaped. There are two or three upper rows and five lower rows of teeth. The first upper row is narrowly interrupted medially, and the third upper row is fragmentary. The upper rows are about equal in length and somewhat longer than the lower rows, all of which are entire and progressively shorter ( fig. 163B ) . Mating Call: The call of Hyla salvador- ensis consists of a short series of short notes. Call groups consist of two to six notes; the duration of each call group varies from 0.27 to 0.78 (mean, 0.38) of a second, and the dura- tion of the notes varies from 0.05 to 0.12 ( mean, 0.083 ) of a second. There are two distinct pulses in each note. The notes are poorly modulated; the dominant frequency varies from 2200 to 2700 (mean, 2345) cycles per second (pi. 22, fig. 2). Recordings obtained at Cerro Uyuca, Hon- duras, revealed that the frogs there produced only two notes in each call group, where frogs at Rancho San Jose, El Salvador, produced from three to six notes in each call group. Natural History: Hyla salvadoren.sis in- habits cloud forests and pine forests, where this species most frequently is encountered along small streams. Males were found calling on Cerro Uyuca on July 5, 1966, and at Rancho San Jose on July 27, 1961. At both places, the frogs called from dense vegetation over the streams. Tadpoles were found on July 21, 1961, at Rancho San Jose. There the tadpoles inhab- ited quiet pools in a rocky stream. Remarks: Fourteen specimens (A.M.N.H. Nos. 54823 and 54827-54839) from Cerro Uyuca, Honduras, are poorly preserved. Lynch and Fugler (1965, p. 6) erroneously referred these specimens to Ptyclwhyla spini- pollex. Etymology: The specific name refers to 1970 DUELLMAN: HYLID FROGS 341 the country of El Salvador, from which the first specimens were taken. Distribution: Hyla salvadorcn.sis occurs at elevations between 700 and 1870 meters on the Pacific slopes of the highlands in northern EI Salvador and south-central Honduras (fig. 164). See Appendix 1 for the locality records of the 30 specimens examined. The Hyla miliaria Group Definition: The members of this group are moderately large to large species; males attain a maximum snout-vent length of 106 mm. The dorsum is green or tan mottled or not with brown or dark green. The palpebral membrane is clear or pigmented ventrally. The hands and feet are immense, and the discs are large. The fingers are at least two-thirds webbed, and the toes are more than three- fourths webbed. Scalloped dermal fringes are present on the outer edge of the forearm and fourth finger and on the outer edge of the foot and fifth toe. The dorsum is tubercu- late in known juveniles and smooth or tuber- Fic. 165. Dorsal (A) and lateral (B) views of the skull of Hyla valancifer (K.U. No. 95416). x 2.5. culate in adults. Males have single, median, subgular vocal sacs and the prepollex vari- ously modified as a projecting spine, spade- like plate or clump of spines. The skull is moderately well ossified; an elongate fronto- parietal fontanelle is present, and in some species, the skin is co-ossified with the fronto- parietals and squamosals. The frontoparietals are expanded laterally over the orbits (fig. 165). The sphenethmoid is broad and extends anteriorly between the nasals, which are great- ly reduced. The quadratojugal is in bony contact with the maxillary, and the median ramus of the pterygoid is in bony contact with the prootic. The anterior arm of the squamosal extends no more than one-half of the distance to the maxillary. The prevomers are reduced and bear transverse or antero- medially inclined dentigerous processes. The palatines are slender. The tadpoles, mating calls, and chromosome numbers are unknown. Composition: Five species (H. echinata, fimbrimembra, miliaria, thysanota, and valan- cifer comprise the group. Fourteen preserved frogs, plus one from South America, were examined, and skulls were removed from two specimens. Comments: Firschein and Smith (1956) and Duellman (1962) considered the Middle American fringe-limbed Hyla to be members of the Hyla tuberculata group. Boulenger (1882a) named Hyla tuberculata on the basis of a single female having a snout-vent length of 67 mm. from Amazonian Ecuador. So few specimens of these bizarre frogs are known that adequate comparisons be- tween species are not possible; adult males of fimbrimembra and thysanota have yet to be found. The absence of tadpoles and record- ings of mating calls further hinders meaning- ful suggestions of relationships. Solely on the basis of the external morphology of the adults, I think that echinata and valancifer are closely related and less specialized than the other species; possibly fimbrimembra should be placed with those two species, but fimbri- membra has the skin on the skull partially co- ossified. Hyla thysanota and miliaria have the largest feet and best developed dermal fringes and thereby seem to be the most advanced species (figs. 166-168). 342 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 166. Hands of the fringe-limbed Hyla. A. H. valandfer, K.U. No. 95416. B. H. cchinata, U.I.M.N.H. No. 49339. C. H. fimbrimembra, R.C.T. No. 761. D. H. thysanota, U.S.N.M. 151080. E. H. miliaria, K.U. No. 30404. x 2. Hyla valancifer Firschein and Smith Hyla valancifer Firschein and Smith, 1956, p. 18 [holotype, U.I.M.N.H. No. 35398 from Volcan San Martin, Veracruz, Mexico; I. Lester Firschein collec- tor]. Duellman, 1960a, p. 55. Diagnosis: This large species (82 mm.) has a smooth dorsum, scalloped fringes, and the fingers about two-thirds webbed; there is no integumentary-cranial co-ossification, and adult males have an ovoid, flattened spade-like, projecting prepollex. The dorsum, flanks, and thighs are reddish brown with dull green markings. Hyla echinata differs by being smaller (60 mm.) and by having 1970 DUELLMAN: HYLID FROGS 343 Fig. 167. Feet of the fringe-limbed Hyla. A. H. valancifer, K.U. No. 95416. B. H. echinata, U.I.M.N.H. No. 49339. C. H. fimbrimembra, R.C.T. No. 761. D. H. tlu/sanota, U.S.N. M. No. 151080. E. H. miliaria, K.U. No. 30404. x 2. 344 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 168. Palmar view of right prepollices of males of fringe-limbed Hijla. A. H. valancifer, K.U. No. 95416. B. H. echinata, U.I.M.N.H. No. 49339. C. H. miliaria, K.U. No. 30404. x 5. dark brown flanks and anterior and posterior surfaces of the thighs contrasting with a pale reddish brown dorsum; breeding males have a clump of nuptial spines on a blunt prepollex. Hyla miliaria has a tuberculate dorsum, fully webbed fingers, and a projecting prepollical spine. Hyla fimbrimembra has integumentary- cranial co-ossification and a creamy tan dor- sum. Hyla thysanota has fully webbed hands and feet and a green dorsum. Description: This is a large species. The one adult male has a snout-vent length of 77.7 mm., and one adult female has a snout- vent length of 82.0 mm. The following pro- portions are for the male and female respec- tively. The ratio of tibia length to snout-vent length is 0.489 and 0.501; the ratio of foot length to snout-vent length is 0.459 and 0.432; the ratio of head length to snout-vent length is 0.318 and 0.317; the ratio of head width to snout-vent length is 0.369 and 0.371, and the ratio of the diameter of the tympanum to that of the eye is 0.831 and 0.782. In two juveniles, having snout-vent lengths of 22.0 and 35.4 mm., the ratio of tibia length to snout-vent length is 0.536 and 0.531, respectively, and the ratio of the diameter of the tympanum to that of the eye is 0.565 and 0.568, respectively. In other proportions, the juveniles do not differ from the adults. The head is about as wide as the body; the top of the head is flat; and the eyes are moderately large and prominent. In dorsal profile, the head is rounded, but the narial region forms a blunt, slightly indented, snout. In lateral profile, the snout is truncate. The snout is moderately long, and the nostrils are noticeably protuberant and situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is rounded and barely discernible posteriorly, but distinct and slightly elevated anteriorly. The loreal region is concave, and the lips are moderately thick and slightly flared. A mod- erately heavy supratympanic fold extends from the posterior corner of the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold covers the upper part of the tympanum, which otherwise is distinct and slightly elevated. The tympanum is posteroventral to the eye and separated from the eye by a distance slightly less than the diameter of the tympanum. The arms are moderately short and robust. A low, scalloped dermal fold extends from the elbow along the ventrolateral edge of the forearm and fourth finger to the base of the disc; a distinct transverse dermal fold is pres- ent on the wrist. Fingers are moderately long and robust and bear large discs; the width of the disc on the third finger is equal to the diameter of the tympanum. The subarticular tubercles are large, round, and flattened; none is bifid. The supernumerary tubercles are small and present in two rows on the proximal segments of the second, third, and fourth fin- gers. A large flat palmar tubercle is confluent with the prepollex, which is enlarged and in an adult male bears a flat, oval, spade-like projection (fig. 168A). The fingers are about 1970 DUELLMAN: HYLID FROGS 345 two-thirds webbed in adults (fig. 166A). The webbing extends from the base of the penulti- mate phalanx of the first finger to the distal end of the antepenultimate phalanx of the second, from the base of the disc of the second to the base of the penultimate phalanx of the third, and on to the base of the disc of the fourth finger. The hind limbs are moderately short and robust; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation ex- tends to the posterior corner of the eye. Two or three large tubercles are present on the heel and a low tarsal fold extends the full length of the tarsus. A low, scalloped fringe is present on the ventrolateral edge of the tarsus and fifth toe. The inner metatarsal tu- bercle is elliptical, flat, and has a raised medial edge. The outer metatarsal tubercle is low, elongate, and rounded. The toes are mod- erately long and bear discs that are distinctly smaller than those on the fingers. The sub- articular tubercles are small and subcorneal, and the supernumerary tubercles are small and indistinct. The toes are about four-fifths webbed (fig. 167A). The webbing extends from the base of the disc of the first toe to the middle of the penultimate phalanx of the second, from the base of the disc of the sec- ond to the middle of the penultimate phalanx of the third, from the base of the disc of the third to the middle of the penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly at the level of the dorsal surfaces of the thighs. A short anal sheath is present, and a few small tubercles are present below the anal opening. In adults, this skin on the dorsum is smooth, except for a few small tubercles in the interorbital area and on the supratympanic fold. In juveniles, the dorsal surfaces of the head, body, and limbs are tuberculate. The skin on the throat, belly, and proximal postero- ventral surfaces of the thighs is granular; that on the other ventral surfaces is smooth. The tongue is nearly round, shallowly notched behind and barely free posteriorly. The den- tigerous processes of the prevomers are trans- verse ridges between the moderately small, round choanae. One adult male has nine teeth on each provomerine process, and one adult female has seven and eight provomerine teeth. A small female ( snout-vent length, 35.4 mm.) has a total of 11 prevomerine teeth. The vocal slits extend a short distance postero- laterally from the midlateral base of the tongue. Apparently the vocal sac is single, median, and subgular. The general coloration of Hyla valancifer is a mottled dull green and brown dorsum with orange spots on the flanks (pi. 2, fig. 3). Notes on the color in life of an adult female (U.M.M.Z. No. 122745) provided by Douglas C. Robinson are as follows: "The dorsum is mottled green and brown with some tan; the flanks are marked with orange spots on a pinkish tan ground color. A dark brown streak extends from the eye to the nostril. The posterior surfaces of the thighs and webbing is purplish pink. The fringes are pinkish tan and the chin is a salmon-color. The tympanum is greenish bronze, and the iris is dark brown." A juvenile female had a pale tan dorsum mottled with dark green; the flanks were mot- tled with ivory and dark chocolate brown (pi. 57, fig. 5). The posterior surfaces of the thighs were reddish brown mottled with cream, and the webbing was reddish brown. The iris was a metallic reddish brown. Duell- man ( 1960a, p. 57 ) , in describing this juvenile female, noted that when the frog was collected the green on the dorsum was pale and irides- cent. During the two weeks that the frog was kept alive, the dorsal ground color often changed to dark reddish brown with olive- green markings, or to pale tan with pale green markings. In preservative, the adults are dull reddish brown with irregular dark brown markings on the dorsum and dorsal surfaces of the limbs. The flanks are somewhat paler. The throat is pale reddish tan, and the belly is creamy white with a suffusion of brown lat- erally. The webbing on the hands and feet is dark brown. Tadpoles: The tadpoles of this species have not been found. Mating Call: The mating call of this species is unknown. Natural History: The four known speci- mens of Hyla valancifer have been collected in cloud forests. I obtained a juvenile female at night. The frog was on the upper side of a 346 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 palm frond about 8 meters above the ground in a shallow ravine. Nothing is known about the habits and life history of this species. Remarks: Firschein and Smith (1956, p. 18) named Hyla valancifer on the basis of a single juvenile having a snout-vent length of 22.0 mm. Duellman (1960a, pp. 55-57) re- ported a second specimen of this species, a juvenile female having a snout-vent length of 35.4 mm. Due to the energetic efforts of Douglas C. Robinson, two adults of this spe- cies are now available. The juveniles differ from the adults in several features. They have proportionately longer legs and smaller tym- pani, and they have slightly less webbing. Juveniles have a tuberculate dorsum, whereas in adults the skin on the dorsum is smooth except for a few small, low tubercles on the head. The snout in juveniles is more truncate than in adults. Were it not for the fact that the two ju- veniles and the two adults were all collected on the same isolated mountain, it might be supposed that the juveniles represent a species distinct from the adults. Despite the obvious differences, the similarities overwhelmingly suggest that the two small specimens are merely juveniles of this large species. Etymology: The specific name valancifer, is derived from the English valance and the Latin suffix -fer meaning to have and is used in the sense of the frog having a decorative valance-like fringe on the limbs. Distribution: Hyla valancifer is known only from elevations of about 1200 meters on Volean San Martin, in the Sierra de los Tux- tlas, in southern Veracruz, Mexico (fig. 169). See Appendix 1 for the locality records of the four specimens examined. Hyla echinata Duellman Hyla echinata Duellman, 1962, p. 349 [holotype, U.I.M.N.H. No. 49339 from Campamento Vista Her- mosa, Oaxaca, Mexico; O. C. Van Hyning collector]. Diagnosis: This species lacks cranial-in- tegumentary co-ossification and osteoderms; it has a smooth dorsum, the fingers about two- thirds webbed, and a cluster of horny spines on a projecting prepollex in males. The flanks and anterior and posterior surfaces of the thighs are dark brown and sharply demarked from the pale reddish brown dorsum. Hyla 98° 18' "w> <-' • H. echinata o H. valancifer KILOMETERS 98° 94° Fig. 169. Distribution of Hyla valancifer and ecliinata. valancifer differs from echinata by being much larger and by having the flanks and dorsum reddish brown; in males of valancifer the pre- pollex bears a smooth spade-like projection. Hyla miliaria differs from echinata by having nearly fully webbed hands and a tuberculate dorsum, and fimbrimembra differs by hav- ing cranial-integumentary co-ossification and creamy tan dorsum, flanks, and thighs. The only other Middle American fringe-limbed hy- lid is Hyla thysanota, which is much larger (95 mm.) than echinata and has a green dor- sum and scalloped fringes. Description: This is a moderately large species known only from two specimens. The snout-vent length of an adult male is 57.0 mm. and of an adult female, 60.2 mm. In the male and female, respectively, the ratio of tibia length to snout-vent length is 0.535 and 0.500; the ratio of foot length to snout-vent length is 0.465 in each; the ratio of head length to snout-vent length is 0.347 and 0.357; the ratio of head width to snout-vent length is 0.308 and 0.312, and the ratio of the diameter of the tympanum to that of the eye is 0.768 and 0.774. The head is wider than the body; the top of the head is flat, and the eyes are moderately large and prominent. In dorsal profile, the lips form a broadly rounded snout, but the internarial area is truncate; in lateral profile, the snout is truncate. The snout is moderately 1970 DUELLMAN: HYLID FROGS 347 long; the nostrils are barely protuberant and and situated at a point about five-sixths of the distance from the eyes to the tip of the snout. The canthus is rounded and moderately ele- vated; the loreal region is concave and the lips are moderately thick and slightly flared. A dermal fold extends posteriorly from the orbit, above the tympanum, and downward to a point above the insertion of the arm. The upper edge of the tympanum is obscured by the dermal fold; otherwise, the tympanum is distinct and elevated above the surrounding skin. The tympanum is posteroventral to the eye and separated from the eye by a distance slightly less than the diameter of the tym- panum. The arms are moderately short and robust. A thin, shallowly scalloped dermal fold ex- tends from the elbow along the ventrolateral edge of the forearm and fourth finger to the base of the disc on the fourth toe. A distinct transverse dermal fold is present on the wrist. The fingers are moderately long and bear large discs; the width of the disc on the third finger is equal to the diameter of the tym- panum. The subarticular tubercles are large and subcorneal; the terminal tubercle on the third and fourth fingers of the right hand in the male are slightly bifid. The supernumer- ary tubercles are small and conical; they are numerous on the proximal segments of all digits. The prepollex is greatly enlarged; an elongate, triangular tubercle is present; the distal end of the prepollex bears a clump of horny spines in the adult male (fig. 168B). The fingers are about two-thirds webbed (fig. 166B). The webbing extends from the base of the penultimate phalanx of the first finger to the distal end of the antepenultimate pha- lanx of the second, from the base of the disc of the second to the base of the penultimate phalanx of the penultimate phalanx of the third and on to the middle of the penultimate phalanx of the fourth finger. The legs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fourth the length of the shank. The tibiotarsal ar- ticulation extends to the nostril. A few small tubercles are present on the heel, and a low, thin, tubercular tarsal fold extends from the heel along the ventrolateral edge of the tarsus and fifth toe to the base of the disc. The inner metatarsal tubercle is moderately small, ellip- tical, flat, and broadly visible from above. The outer metatarsal tubercle is absent. The toes are moderately short and bear discs that are noticeably smaller than those on the fingers. The subarticular tubercles are small and sub- conical; the supernumerary tubercles are small, conical, and numerous on the proximal segments of all digits. The toes are nearly fully webbed (fig. 167B). The webbing ex- tends from the base of the disc of the first toe to the base of the penultimate phalanx of the second, from the base of the disc of the sec- ond to the base of the penultimate phalanx of the third, from the base of the disc of the third to the middle of the penultimate phalanx and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly near the level of the upper surfaces of the thighs. A short anal sheath and a few tuber- cles below the anus are present. The skin on the throat, belly and ventral surfaces of the arms and thighs is granular; that on the ven- tral surfaces of the tarsi is finely granular, and the skin on the dorsum and ventral surface of the shank is smooth. The tongue is broadly cordiform, shallowly notched behind, and barely free posteriorly. The dentigerous pro- cesses of the prevomers are narrowly sepa- rated transverse ridges between small, round choanae. In each specimen, there are seven teeth on each process, for a total of 14 pre- vomerine teeth in each specimen. The vocal slits are short and extend posterolaterally for a short distance from the midlateral base of the tongue. The vocal sac is single, median, and subgular. The general coloration of Hyla echinata is pale reddish brown above with dark brown flanks (pi. 2, fig. 2). Notes on the coloration in life of an adult female were provided by Dale L. Hoyt. He described the dorsum as being pale reddish brown; the flanks and an- terior surfaces of the thighs are dark brown, and this lateral color is clearly demarked from the paler dorsal color. The posterior surfaces of the thighs are dark brown, almost black. The ventral surfaces of the shanks and feet, and the webbing, is dark brown. A few creamy yellow flecks are present on the flanks, and a transverse white line is present above 348 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 the anus. The belly is dusty cream, and the tympanum is coppery tan. In preservative, the dorsum is dull reddish tan or purplish brown. The flanks, anterior and posterior surfaces of the thighs, and the webbing on the hands and feet are purplish black. The venter is dull creamy tan, except on the shanks and feet, which is brown. A faint suffusion of brown is noticeable on the chin. There is a narrow creamy tan line along the margin of the upper lip and a creamy white stripe above the anus. The fringes on the feet and forearms are creamy tan, and the tympanum is coppery tan. Tadpoles: The tadpoles of this species have not been found. Mating Call: The mating call of this species is unknown. Natural History: Hijla echinata is known only from the cloud forest in the mountains of northern Oaxaca, Mexico. One specimen was obtained from a bromeliad, and the other was found on a branch of a tree near a stream in the cloud forest. Remarks: Hyla echinata seems to be most closely related to Hijla valancifer, from which it differs principally by having emarginate, in- stead of scalloped, fringes and spiny nuptial excrescences, instead of a spade-like prepol- lex. Insofar as known, echinata is the only fringe-limbed hylid having nuptial excres- cences composed of a cluster of horny spines. Etymology: The specific name is Latin and means spiny or thorny and is used in ref- erence to the nuptial excrescences in the breeding male. Distribution: Hyla echinata is known only from cloud forests at elevations of about 1500 meters on the northern slopes of the Sierra de Juarez in northern Oaxaca, Mexico (fig. 169). See Appendix 1 for the locality records of the two specimens examined. Hyla fimbrimembra Taylor Hyla richardi Taylor 1948b, p. 233 [holotype, R.C.T. No. 761 from the American Cinchona Planta- tion, Alajuela Province, Costa Rica; Richard C. Tay- lor collector (not Hyla richardii Baird, 1854 (=HyIa versicolor) from Cambridge, Massachusetts)]; 1952c, p. 819. Hyla fimbrimembra Taylor, 1948b, p. 235 [holo- type, R.C.T. No. 764 from Isla Bonita, Heredia Prov- ince, Costa Rica; Richard C. Taylor collector] ; 1952c, p. 821. Hyla richardtaylori Taylor 1954b, p. 624 [replace- ment name for Hyla richardi Taylor, 1948, preoccu- pied]. Diagnosis: In adults of this species the skin is co-ossified with the underlying cranial elements on the top of the skull; the dorsum is minutely granular ( tubercular in juveniles ) , and the hands are about two-thirds webbed. The dorsum, flanks, and limbs are creamy tan; faint, darker, narrow bands are present on the limbs. Hyla fimbrimembra differs from all other known fringe-limbed hylids by having integumentary-cranial co-ossification and from all other Middle American hylids with co- ossified skulls by having dermal fringes on the outer edges of the limbs. Description: This species is represented in collections by one juvenile and one adult female having a snout-vent length of 70.8 mm. In the latter specimen, the ratio of tibia length to snout-vent length is 0.517; the ratio of foot length to snout-vent length is 0.465; the ratio of head length to snout-vent length is 0.350; the ratio of head width to snout-vent length is 0.372, and the ratio of the diameter of the tympanum to that of the eye is 0.780. The juvenile has a snout-vent length of 29.7 mm.; the proportions of the limbs and head are larger than in the adult, and the tympanum is proportionately smaller (tympanum/eye ratio, 0.595). The head is slightly wider than the body; the top of the head is flat, and the eyes are prominent. The skin on the top of the head posterior to the anterior edges of the orbit is co-ossified with the underlying cranial ele- ments. In dorsal profile, the snout is acutely rounded; in lateral profile, the snout slopes abruptly from the nostrils to the edge of the upper lip. The snout is moderately long; the nostrils are protuberant and situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is round- ed, but not elevated; the loreal region is con- cave, and the lips are moderately thin and somewhat flared. A thin dermal fold extends posteriorly from the orbit, above the tym- panum, and downward towards the angles of the jaws; at a point about midway between the upper edge of the tympanum and the an- gles of the jaws, the fold curves posteriorly and 1970 DUELLMAN: HYLID FROGS 349 terminates at a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and elevated; the tympanum is separated from the eyes by a distance equal to about one and one- half times the diameter of the tympanum. The arms are moderately long and slender. A thin transverse dermal fold is present on the wrist, and a broad, sharply scalloped der- mal fringe extends the length of the forearm from the elbow to the base of the disc of the fourth finger. The fingers are moderately long and robust and bear large discs. The disc on the third finger is slightly larger than the tym- panum. The subarticular tubercles are mod- erately large and conical; none are bifid. The supernumerary tubercles are conical and pres- ent in a single row on the proximal segments of each digit except that additional tubercles are present on the thumb and on the base of the fourth finger. The palmar tubercle is small and conical. The prepollex is elongate, rec- tangular, and blunt terminally. The fingers are about two-thirds webbed (fig. 166C). The webbing is vestigial between the first and sec- ond fingers, and extends from the base of the disc of the second to the distal end of the antepenultimate phalanx of the third and from the base of the penultimate phalanx of the third to the base of the disc of the fourth finger. The legs are long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to the eye. A thin transverse dermal fold and several point- ed tubercles are present on the heel. A thin, sharply scalloped dermal fringe is present on the outer edge of the tarsus from the heel to the base of the disc of the fifth toe. A fringe- like, elevated tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is elongate, flattened, and barely visible from above. The outer metatarsal tubercle is small and conical. The toes are moderately long and slender, and bear discs that are noticeably smaller than those on the fingers. The sub- articular tubercles are small and round. The supernumerary tubercles are very small and subcorneal; they are irregularly arranged in a single row on the proximal segment of each digit. The toes are about three-fourths webbed (fig. 167C). The webbing extends from the distal end of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the base of the disc of the second to the base of the penultimate phalanx of the third, from the base of the disc of the third to the base of the penultimate phalanx of the fourth, and on to the base of the fifth toe. The anal opening is directed posteriorly near the upper level of the thighs. A short anal flap is present; and there are granular dermal folds extending ventrolaterally from the anal opening. The dorsal surfaces are smooth, except for small tubercles on the dorsal surfaces of the limbs. The skin on the throat, belly, and ventral surfaces of the thighs is granular, and that on the other ventral sur- faces is smooth. The tongue is cordiform, shallowly notched posteriorly, and barely free behind. The dentigerous processes of the pre- vomers are narrowly separated transverse ridges between the moderately large, round choanae. Eight teeth are present on each process. Structurally, the juvenile differs from the adult female just described by having a more truncate snout in dorsal profile and a definitely truncate snout in lateral profile. The dermal folds below the anal opening are more promi- nent in the juvenile. Small tubercles are pres- ent on the dorsal surfaces of the head and body, as well as on the limbs, in the juvenile. The juvenile specimen lacks integumentary- cranial co-ossification. According to Taylor (1948b, p. 234) the color in life of the adult female (R.C.T. No. 761) was "nearly uniform lavender brown with very indistinct darker markings; discs on all fingers and toes blue-black; edge of lower jaw bluish black; a narrow line of black on edge of upper lip; throat yellow-brown with fine purple reticulations; venter and underside of thighs lavender brown with cream marks; underside of hands and feet lavender; no light mark on vent." Taylor (1948b, p. 237) de- scribed the color of the juvenile (R.C.T. No. 764) as follows: "Brownish gray above, the extremities more ashen gray; chin and venter white with strong lavender reticulations on skin; on edge of underside of arms is deep lavender stripe; elevated area on head black- ish brown; limbs very faintly barred; some 350 MONOGRAPH MUSEUM OF NATURAL HISTORY NO 1 brown flecks forming a short diagonal line on thighs; some flecks of brown in groin." In preservative, the dorsum of the adults is pale tan with a few small purplish brown spots on the back and faint, narrow brown bars on the limbs (pi. 3, fig. 1). The venter is creamy tan. The edge of the upper lip, the edge of the chin, and the discs on the fingers and toes are lavender-brown. The juvenile is colored like the adult, except that the bands on the limbs are more prominent, and small dark flecks are present on the flanks. The juvenile lacks the dark color on the discs and on the edges of the upper lip and chin, where- as it possesses fine dark brown reticulations on the chin. Tadpoles: The tadpoles of this species have not been found. Mating Call: The mating call of this species is unknown. Natural History: The two specimens of Hyla fimbrimembra were obtained in humid montane forests. The juvenile was found cling- ing to a small plant bathed in the spray of a waterfall at night (Taylor, 1952c, p. 824). The adult was found by day beneath the bark of a standing dead tree (Taylor, personal com- munication ) . Remarks: Taylor ( 1948b) named two spe- cies of fringe-limbed tree frogs from Costa Rica — Hyla richardi and Hyla fimbrimembra. Hyla richardi Taylor, 1948b, is preoccupied by Hyla richardii Raird, 1854; this was noted by Taylor ( 1954b ) , who proposed the replace- ment name, Hyla richardtaylori for Hyla rich- ardi Taylor, 1948b. I am treating Hyla richard- taylori and Hyla fimbrimembra as conspecific. Although Hyla richardi Taylor has page pri- ority over Hyla fimbrimembra Taylor, because the former is preoccupied and was given the replacement name Hyla richardtaylori in 1954, the correct name for this frog is now Hyla fimbrimembra. There is little doubt but what the two specimens on which Taylor ( 1948b ) based his descriptions of two species represent a single taxon. Although one specimen is a juvenile, it is like the adult, and differs from all other known fringe-limbed hylids, by having the curved supratympanic fold, dermal folds be- low the anal opening, sharply scalloped fringes on the arms and feet, and narrow dark trans- verse bands on the limbs. The juvenile differs from the adult by lacking integumentary- cranial co-ossification and by having a more blunt snout and tuberculate dorsum. The ontogenetic change in the shape of the snout and in the tuberosity parallels the change in the closely related Hyla valancifer. The ab- sence of co-ossification apparently is char- acteristic of juveniles of species in which the skin becomes co-ossified with the underlying cranial elements in the adult ( Trueb, 1966 and 1969). Etymology: The specific name is derived from the Latin fimbria, meaning fringe, and the Latin membrum, meaning part of member and refers to the dermal fringes on the limbs. Distribution: Hyla fimbrimembra is known only from elevations of about 1500 meters on the Caribbean slopes of Volcan Poas in Costa Rica (fig. 170). See Appendix 1 for the locality records of the two specimens examined. Hyla thysanota Duellman Hyla thysanota Duellman, 1966a, p. 259 [holotype, U.S.N.M. No. 151080 from Cerro Mali, Darien Prov- ince, Panama, elevation 1265 meters; Charles O. Handley, Jr. collector]. Diagnosis: This large (95 mm.) species differs from all other known fringe-limbed hylids by having a uniformly green dorsum. The skin on the dorsum is granular, and the hands and feet are fully webbed; there is no integumentary-cranial co-ossification. All oth- er moderate to large green hylids in Middle America lack scalloped dermal fringes on the outer edges of the limbs. Description: This large species is known from a single female having a snout-vent length of 95.7 mm. The ratio of tibia length to snout-vent length is 0.533; the ratio of foot length to snout-vent length is 0.466; the ratio of head length to snout-vent length is 0.325; the ratio of head width to snout-vent length is 0.381; and the ratio of the diameter of the tympanum to that of the eye is 0.578. The head is wider than the body, and the top of the head is flat. In dorsal profile, the snout is broadly rounded, and in lateral profile, it is round. The snout is moderately long; the nostrils are protuberant laterally and situated at a point about three-fourths of the distance from the eyes to the tip of the snout. The 1970 DUELLMAN: HYLID FROGS 351 KILOMETERS Fig. 170. Distribution of Hyla miliaria, thijsanota, and fimbrimcmbra. canthus is heavy and rounded; the loreal re- gion is deeply concave, and the lips are broad and flaring. A moderately heavy dermal fold extends posteriorly from the eye to the point above the insertion of the arm. The upper edge of the tympanum is obscured by the dermal fold; otherwise, the tympanum is dis- tinct. The arms are moderately long and slender. Two thin transverse dermal folds are present on the wrist, and a thin, scalloped dermal fringe extends along the outer edge of the forearm from the elbow to the disc of the fourth finger. The fingers are moderately short and robust and bear large discs; the discs on all fingers, except the first, are larger than the tympanum. The distal subarticular tubercle on the fourth finger is flattened; the other subarticular tubercles are large and conical. The supernumerary tubercles are small, conical, and numerous on the proximal segments of each digit. There is no palmar tubercle, but an elongate, flat tubercle is pres- ent on the prepollex, which is only moderately enlarged. The fingers are nearly fully webbed ( fig. 166D ) . The webbing extends to the bases of the penultimate phalanges between the first and second fingers and connects the other fingers at the bases of the discs. The legs are moderately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation extends to the eye. A distinct transverse dermal fold is present on the heel, and a thin tarsal fold curves from the heel to the inner metatarsal tubercle. A thin, scal- loped dermal fringe extends along the outer edge of the foot from the heel to the disc of the fifth toe. The inner metatarsal tubercle is flat, broadly eliptical and visible from above; the outer metatarsal tubercle is absent. The toes are moderately long and slender and bear discs that are nearly as large as those on the fingers. The subarticular tubercles are coni- cal; the supernumerary tubercles are small, conical, and in a single row on the proximal segment of each digit. The toes are fully webbed (fig. 167D). The anal opening is directed posteriorly at the midlevel of the thighs. The anal sheath is short and granular; a distinct granular der- mal fold is present on each side of the anal opening. The skin on the top of the head and body is finely granular; that on the belly and median posteroventral surfaces of the thighs is granular, whereas that on the other surfaces is smooth. The tongue is broadly cordiform, shallowly notched posteriorly, and barely free behind. The dentigerous processes are nar- rowly separated transverse ridges between the 352 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 small, round choanae. There are 10 teeth on one ridge and 11 on the other. According to color notes taken by Charles O. Handley, Jr., in life the dorsum was green, and the ventral surfaces were pinkish white; the iris was brown. In preservative, the dor- sum was dark purplish brown (pi. 3, fig. 2). The lower parts of the flanks, the anterior and posterior surfaces of the thighs, and the ven- tral surfaces of the hind limbs are pale brown; the webs are dark brown. The belly is creamy yellow with brown spots anteriorly, and the chin is brown. The upper lip is gray-white. Tadpoles: The tadpoles of this species have not been found. Mating Call: The mating call of this species is unknown. Natural History: The only known speci- men was found in a tree top at night in humid montane forest near the head waters of the Rio Pucro. Remarks: Nothing can be added to the original description by Duellman ( 1966a ) . Etymology: The specific name is derived from the Greek ihysanotos, meaning fringed, and refers to the dermal fringes on the arms and feet. Distribution: Hyla ihysanota is known from an elevation of 1265 meters on the east slope of Cerro Mali in the Serrania del Darien in eastern Panama (fig. 170). See Appendix 1 for the locality record of the one specimen examined. Hyla miliaria (Cope) Hypsiboas miliarius Cope, 1886, p. 272 [holotype, U.S.N.M. No. 14193 from "Nicaragua"; John F. Bransford collector]. Hyla miliaria: Gunther, 1901 (1885-1902), p. 283. Hyla phantasmagoria Dunn, 1943, p. 309 [holo- type, M.d.L.S. No. 267 from the Rio Cauca, Anrioquia- Bolivar border, Colombia; Hermano Daniel collector]. Plectrohyla miliaria: Taylor and Smith, 1945, p. 596. Hyla immensa Taylor, 1952c, p. 815 [holotype, K.U. No. 30404 from the Institute Interamericano de Ciencias Agricolas, 2 kilometers east of Turrialba, Cartago Province, Costa Rica; Edward H. Taylor collector]. Diagnosis: This huge frog (106 mm.) is readily distinguished from all other Middle American hylids by having a tuberculate dor- sum in juveniles and adults, fully webbed hands and feet, and in adults osteoderms, which give the head the appearance of having the skin co-ossified with the underlying cranial elements. The tips of the granules on the venter are keratinized in adults, and in breed- ing males the prepollical spine is protruding. Superficially, Hyla miliaria resembles the West Indian Hyla lichenoid in size and the tubercu- late dorsum, but the latter is casque-headed. Description: This is the largest known species of fringe-limbed hylids. Four males have snout-vent lengths of 57.2 to 106.0 mm.; the ratio of tibia length to snout-vent length is 0.466 to 0.566 (mean, 0.525); the ratio of foot length to snout-vent length is 0.420 to 0.533 ( mean, 0.471 ) ; the ratio of head length to snout-vent length is 0.317 to 0.365 (mean, 0.340); the ratio of head width to snout-vent length is 0.360 to 0.410 (mean, 0.386), and the ratio of the diameter of the tympanum to that of the eye is 0.493 to 0.753 ( mean, 0.642) . The single known female has a snout-vent length of 69.7 mm. and in proportions does not exceed the limits of variation known in the males. One juvenile has a snout-vent length of 41.3 mm. The head is as wide as the body and the top of the head is flat. In dorsal profile, the head is rounded, and the snout is truncate; in lateral profile the snout is truncate. The snout is short, and the nostrils are protuberant and situated at a point about five-sixths of the dis- tance from the eyes to the tip of the snout. The internarial area is noticeably depressed. The canthus is rounded, and the loreal region is deeply concave; the lips are moderately thick and flared. A bony ridge followed by a dermal fold extends posteriorly from the eye above the tympanum, to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which other- wise is distinct, elevated, and separated from the eye by a distance slightly less than the diameter of the tympanum. The arms are short and extremely robust. A heavy transverse dermal fold is present on the wrist. A heavy, scalloped dermal fringe extends along the ventrolateral edge of the forearm from the elbow to the wrist and then along the outer edge of the fourth finger. The hand is immense. The fingers are mod- erately long and robust and bear huge discs; 1970 DUELLMAN: HYLID FROGS 353 the width of the disc on the third finger is half again as wide as the diameter of the tympanum. The subartieular tubercles are large; the distal one on the fourth finger is flattened and in some specimens, it is bifid; the other subartieular tubercles are round. The supernumerary tubercles are large, coni- cal, and arranged in a single row on the proxi- mal segment of each digit. A flat, partially bifid palmar tubercle is present. The prepollex is greatly enlarged and curved backwards terminally. In one large male the prepollical spine protrudes from the prepollex (fig. 168C). The fingers are nearly fully webbed (fig. 166E). The webbing extends from the base of the penultimate phalanx of the first finger to the base of the penultimate phalanx of the second and connects the other fingers at the bases of the webs. The legs are mod- erately long and robust; the heels of the ad- pressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articu- lation extends to the eye. A distinct, transverse dermal fold is absent on the heel, but numer- ous small tubercles are present on the heel. A broad, thin, scalloped dermal fringe extends from the heel along the ventrolateral edge of the tarsus to the base of the disc on the fifth toe. A distinct, curved, tarsal fold is present. The inner metatarsal tubercle is elongately elliptical with an elevated outer edge. Sev- eral small tubercles are present distally on the tarsus, so it is impossible to determine if an outer metatarsal tubercle, per se, is present. The toes are moderately long and robust and bear discs that are slightly smaller than those on the fingers. The subartieular tubercles are large and subcorneal, and the supernumerary tubercles are small, conical, and arranged in a single row on the proximal segments of each digit. The toes are webbed to the bases of the discs (fig. 167E). The anal opening is directed posteroven- trally at the midlevel of the thighs. A broad, granular anal sheath is present, and many pointed tubercles are present below the anal opening. The skin on the dorsum is tubercu- lar. Tubercles are best developed on the head and midthoracic region. Apparently, in large individuals, osteoderms are present in the skin, and possibly there is a small amount of integumentary-cranial co-ossification; in the two largest specimens, the skin seems to be co-ossified with the skull, but in an adult male having a snout-vent length of 70.2 mm. the skin is not co-ossified with the underlying cranial elements. The skin on the throat, belly, and ventral surfaces of the arms and thighs is granular. In the two largest specimens (both having snout-vent lengths of more than 100 mm.) the tubercles have horny tips. The ventral surfaces of the shanks are smooth. The tongue is broadly cordiform, barely free be- hind, and only shallowly, if notched at all, posteriorly. The dentigerous processes of the prevomers are elongate, narrowly separated, transverse ridges between the posterior mar- gins of the moderately large, ovoid, choanae. Four males have nine to 17 teeth on each process and a total of 19 to 33 (mean, 23.8) prevomerine teeth; the one female has nine teeth on one process and 11 on the other. The vocal slits extend from the posterolateral base of the tongue towards the angles of the jaws. The vocal sac is single, median, and subgular. The general coloration of Hyla miliaria is mottled brown and tan (pi. 44, fig. 1). The coloration in life of an adult male (K.U. No. 101610) was as follows; the dorsum was mottled dark brown, orange-tan, and metallic green. The chin was pale brown with dark brown spots and white tubercles. The belly was pale tan, and the ventral surfaces of the legs were pinkish tan. The anterior and pos- terior surfaces of the thighs were pale brown with dark brown mottling. The webbing and the discs were brown with dark brown streaks on the former and flecks on the latter. The anal region was creamy white, and the tym- panum was brown. The iris was bronze with reddish brown reticulations, and the palpe- brum was pale tan mottled with dark metallic green. In preservative, the four males and one juvenile are dull brown with darker brown markings, consisting of irregular bronze re- ticulations on the back and faint transverse bands on the limbs. The venter in the two largest males is brown mottled with cream, whereas the smaller specimens have a venter that is predominately cream with brown spots. The one female (K.U. No. 98451) is pale tan dorsally with a dark brown inter- 354 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 orbital spot and dark brown spots in the sacral region; dark brown transverse bands are present on the limbs, and the venter is immaculate creamy tan, except for small brown flecks on the edge of the chin. Tadpoles: The tadpoles of this species have not been found. Mating Call: Recordings of the call of this species are not available, nor have I heard this species call. Mr. Ratibor Hartmann of Finca Santa Clara, Chiriqui Province, Pan- ama, told me of hearing a loud growl-like call from a large oak tree in a cafetal. We obtained one specimen of Hyla miliaria from this oak tree. Natural History: On the basis of the locality records of Hyla miliaria, it is presumed that the species inhabits humid tropical and montane forests. Taylor (1952c, p. 818) ob- tained one specimen "from mud at the bottom of a water-filled cavity in a tree, about 5 feet above the ground" at Turrialba, Cartago Prov- ince, Costa Rica. One specimen from Finca Santa Clara, Chiriqui Province, Panama, was found at night about 4 meters above the ground on a limb of a tree. Mr. Louie Hartmann of Finca Santa Clara told me of having seen a large "flying frog" in the forest at Finca Santa Clara. After col- lecting a specimen of Hyla miliaria there, ob- servations were made on the jumping ability of the frog. The frog when leaping, extends the forefeet and the hindlimbs and widely spreads the fingers and toes. The extensive webbing on the large hands and feet, together with the dermal fringes on the arms and feet provide a large surface area. Furthermore, when leaping, the fingers are turned slightly upward (pi. 6). In such a position, the frog is capable of gliding, and this one individual was observed to glide for a distance of about 3 meters while losing less than 1 meter of altitude. Dunn (1943, p. 311) suggested that the large size, rugosity, big discs, and webbing of Hyla phantasmagoria and other fringe- limbed tree frogs were "characters adapting frogs to live in the roof of the forest, under conditions of high evaporation rate. In order to cope with the aridity of the environment, they must become large and rugose, like toads. The great discs are obviously correlated with the size of frogs and the climbing ability." The rugosity, thickness of the skin, and presence of osteoderms probably do protect the frog from desiccation; the presence of the large discs and the gliding ability indicate that the frogs of this species are strictly arboreal. Prob- ably they do inhabit the forest canopy; conse- quently, they are rare in collections. Remarks: I have compared the holotype of Hyla phantasmagoria Dunn, 1943 (M.d.L.S. No. 267) with that of Hyla immensa Tavlor, 1952c, (K.U. No. 30404), and I have compared the latter with the holotype of Hyla miliaria Cope, 1886 (U.S.N.M. 'No. 14193). Dunn (1943, p. 309) stated that the skin of the head was co-ossified with the skull to form a casque in the type of Hyla phantasmagoria. In that specimen, there is partial co-ossification that is the same as in the type of Hyla immensa. In the smaller specimens, including the type of Hyla miliaria, the skin is not co-ossified with the underlying cranial elements. The only observable difference is structure between the types of Hyla phantasmagoria and Hyla im- mensa is that the prepollical spine protrudes in immensa and does not in phantasmagoria. The spine is not protruding in any of the smaller specimens, including the type of mi- liaria. The nature of the prepollical spine probably is correlated with age and breeding condition. There are differences in proportions among the type specimens, but two individuals from Panama have proportions that indicate that the differences observed in the types are individual variations within one species. The amount of dark pigment on the venter is greatest in the largest specimens, the types of Hyla immensa and phantasmagoria. The type specimen of Hyla miliaria has the most contrasting ventral coloration; in this speci- men, the venter is cream with large brown spots. Etymology: The specific name is Latin and was used by Cope apparently in the sense of miliary, an inflammatory disorder of the skin resulting in the formation of small erup- tions— in reference to the tubercular skin. Distribution: Hyla miliaria is known defi- nitely from elevations of 600 to 1200 meters on the Caribbean and Pacific slopes of the Costa Rican and western Panamanian high- lands and from an unknown locality in Nica- 1970 DUELLMAN: HYLID FROGS 355 ragua and from central Colombia (fig. 170). See Appendix 1 for the locality records of the five specimens examined. The Hyla godmani Group Definition: The members of this group are medium-sized frogs; males attain a maxi- mum snout-vent length of 45 mm. The dor- sum is pale gray or tan to brown. The hidden surfaces of the legs and the webbing is yellow or red. The palpebral membrane is clear. The fingers are about three-fifths webbed and the toes are more than three-fourths webbed. Dermal folds and appendages are lacking on the limbs. An extensive axillary membrane is present. Males have a single, median, sub- gular vocal sac, but lack horny nuptial excres- cences on the pollices. The cranial elements are only moderately ossified (fig. 171), espe- cially with respect to the sphenethmoid, fron- toparietals, and otic region. The nasals are small and widely separated medially; the maxillary process of the nasal does not articu- late with the maxillary or the palatine. The frontoparietals have a minimal amount of os- sification laterally; the large frontoparietal fontanelle is bordered posteriorly by the exoc- cipitals. The distal one-third of the crista Fig. 171. Dorsal (A) and lateral (B) views of the skull of Hyla loquax, K.U. No. 59906. X 2.75. parotica is cartilaginous; thus the squamosal does not articulate with the bony prootic. The anterior arm of the squamosal extends no more than half of the distance to the maxillary. The well-developed quadratojugal is in bony contact with the maxillary. The pterygoid is robust; the medial ramus articulates with the poorly ossified prootic. Prevomerine teeth are present. The tadpoles are pelagic pond types with moderately deep, terminally pointed cau- dal fins and anteroventral mouths having two upper and three lower rows of teeth. The mating call consists of a series of loud, quickly repeated notes that have distinct pulses and harmonics. The haploid number of chromo- somes is 12 (known only in loquax). Composition: Two species, godmani and loquax comprise the group, which is restricted to Middle America. Of these two species, 896 preserved frogs, 20 skeletons, three lots of tad- poles, and two preserved clutches of eggs have been examined. Comments: Smith and Taylor (1948, p. 79) recognized a "loquax group," in which they placed eight species of Hyla: loquax, rickardsi (= godmani, fide Duellman, 1964c), rozellae ( =Ptychohyla e. euthysanota, fide Duellman, 1963c), picta, smithii, ebraccata, robertmertensi, and undencoodi (=micro- cephala undencoodi, fide Smith, 1951). The latter two species are members of the micro- cephala group, and ebraccata is in the leuco- phyllata group. Both of these groups differ osteologically from the godmani group by lacking a quadratojugal. Members of these groups have a haploid chromosome number of 15, and their tadpoles have terminal mouths lacking teeth. Hyla picta and smithii com- prise a group differing from the godmani group by small size, absence of an axillary membrane, and a mating call consisting of a series of short, high-pitched notes. The two species in the godmani group in- habit humid forested lowlands and foothills. Apparently they differentiated through isola- tion by the development of subhumid environ- ments in the Isthmus of Tehuantepec in the Pleistocene. At the present time their ranges are narrowly separated, but if they occurred sympatrically the distinctly different mating calls probably would serve as an effective isolating mechanism. 356 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Hyla godmani Gunther Hijla godmani Gunther, 1901 (1885-1902), p. 275 [syntypes, B.M.N.H. Nos. 1901.12.19.88-95 from Jala- pa, Veracruz, Mexico; Frederick D. Godman collector; B.M.N.H. No. 1901.12.19.96 from Misantla, Veracruz, Mexico; Frederick D. Godman collector]. Duellman, 1964c, p. 455 [selection of B.M.N.H. No. 1901.12.19.96 as lectotype]. Hyla miotympanum: Kellogg, 1932, p. 170. Smith and Taylor, 1948, p. 90 [part, specimen from Misantla, Veracruz]. Hyla dckardsi Taylor, 1939a, p. 385 [holotype, F.M.N. H. No. 100077 (formerly E.HT.-H.M.S. No. 5947 ) from Potrero Viejo, Veracruz, Mexico; Edward H. Taylor and Dyfrig Forbes collectors]. Smith and Taylor, 1948, p. 85. Diagnosis: This medium-sized gray or tan frog with an extensive axillary membrane is characterized by an acutely rounded snout, angular canthus, and yellow webbing. This combination of characters readily distin- guishes godmani from loquax, which has a blunt snout, rounded canthus, and red web- bing. The only other Middle American hylid with an extensive axillary membrane is the small Hyla ebraccata, which has yellow thighs (pigmentless in preservative) and usually a contrasting pattern on the dorsum. Description: Males of this medium-sized species attain a maximum snout-vent length of 38.0 mm. and females reach 36.6 mm. In a series of 25 males from Mata Oscura, Vera- cruz, Mexico, the snout-vent length is 33.5 to 38.0 (mean, 35.6) mm.; the ratio of tibia length to snout-vent length is 0.496 to 0.529 (mean, 0.512); the ratio of foot length to snout-vent length is 0.421 to 0.463 ( mean, 0.443); the ratio of head length to snout-vent length is 0.283 to 0.333 (mean, 0.296); the ratio of head width to snout-vent length is 0.312 to 0.349 (mean, 0.331), and the ratio of the diameter of the tympanum to that of the eye is 0.455 to 0.645 (mean, 0.552). Four females from the same locality have snout- vent lengths of 32.2 to 36.6 (mean, 35.0) mm.; the females do not differ significantly in any proportion from the males. The head is slightly wider than long but narrower than the body. The top of the head is flat, and the eyes are prominent. In dorsal profile the snout is acutely rounded; in lateral profile it is bluntly rounded. The snout is moderately short; the nostrils are barely pro- tuberant and situated at a point about two- thirds of the distance from the eyes to the tip of the snout. The canthus is barely angular, but distinct; the loreal region is barely con- cave, and the lips are moderately thick but not flared. A thin dermal fold extends pos- teriorly from the orbit, above the tympanum, and to a point above the insertion of the arm. The fold obscures the upper edge of the tym- panum, which otherwise is distinct and sepa- rated from the eye by a distance equal to about two-thirds of the diameter of the tym- panum. The arms are moderately long and slender; an extensive axillary membrane terminates on the posterior surface of the arm at a point about three-fourths of the distance from the axilla to the elbow. Tubercles are absent on the ventrolateral surface of the forearm, but a thin transverse dermal fold is present on the wrist. The fingers are moderately long and bear large discs; the width of the disc on the third finger is equal to the diameter of the tympanum. The subarticular tubercles are large and conical; none is bifid. The super- numerary tubercles are moderately large and conical; they are present only on the proximal segments of each digit. The palmar tubercle is large, flat, and partially bifid. The prepol- lex is moderately enlarged and in breeding males lacks a horny nuptial excrescence. The fingers are about one-half webbed ( fig. 172A ) . The webbing extends from the distal end of the antepenultimate phalanx of the first finger to the middle of the antepenultimate phalanx of the second, from the distal end of the penul- timate phalanx of the second to the middle of the antepenultimate phalanx of the third, and from the distal end of the antepenultimate phalanx of the third to the base of the penul- timate phalanx of the fourth finger. The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A thin transverse dermal fold is present on the heel. In some speci- mens, a weak tarsal fold is present distally, but in most individuals the tarsal fold is ab- sent. The inner metatarsal tubercle is elon- gately oval, flat, and barely visible from above. The outer metatarsal tubercle is small 1970 DUELLMAN: HYLID FROGS 357 Fig. 172. Hands and feet of members of the Hylu godmani group. A and C. Hyla goclmani, K.U. No. 64961. B and D. Hyla loquax, K.U. No. 103686. X 3. and subcorneal. The toes are moderately long and have discs that are only slightly smaller than those on the fingers. The subarticular tubercles are moderately large and round. Small, subcortical supernumerary tubercles are present on the proximal segments of each digit. The toes are about three-fourths webbed ( fig. 172C ) . The webbing extends from the distal end of the penultimate phalanx of the first toe to the distal end of the ante- penultimate phalanx of the second, from the base of the disc of the second to the distal end of the antepenultimate phalanx of the third, from the distal end of the penultimate phalanx of the third to the base of the penul- timate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly- near the level of the upper edges of the thighs; a short anal sheath is present. Numerous small tubercles are present below the anal opening. In general appearance the skin on the dorsum is smooth, but under magnifica- tion it is minutely corrugated. The skin on the throat and ventral surfaces of the limbs, except the thighs, is smooth; that on the belly and ventral surfaces of the thighs is granular. The tongue is small, ovoid, or broadly cordi- form with a shallow notch behind and barely free posteriorly. The dentigerous processes of the prevomers are posteromedially inclined elevations that are broadly separated medially and situated between the moderately large ovoid ehoanae. Males have four to six teeth on each process and a total of eight to 12 (mean, 10.2) prevomerine teeth. Females have three to six teeth on each process and a total of seven to 11 (mean, 9.3) prevomerine teeth. The vocal slits are long and extend along the inner edge of the lower jaws from a point opposite the base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration is uniform or faintly mottled gray, tan, or yellowish brown above and yellow below (pi. 55, fig. 3). When calling or active at night, individuals usually are a pale yellowish tan above. By day, the dorsal coloration changes to pale grayish tan or pale brown, or in some specimens, remains the same. Dark green, brown, or black flecks are present on the dorsum; in some speci- mens, paler tan or gray spots also are apparent during the day. Posterior surfaces of the thighs are dull yellow. The venter is pale lemon yellow, and the vocal sac is slightly duller yellow. The iris is dull bronze with a slight reddish tinge. In some individuals, distinct transverse dark marks are present on the forearms and shanks. In some specimens, these marks con- sist of a series of short dashes or small spots, whereas in others distinct transverse bars are present. In the latter ease, usually every other bar is about twice as wide as the intervening dark bars. Metachrosis is extreme in this frog; the change in coloration in a given indi- vidual encompasses the entire range of varia- tion known in the species. In preservative, the dorsum varies from pale grayish white to creamy tan or pale brown. In most specimens, some dark flecks, spots, or reticulations are present on the back. The posterior surfaces of the thighs are pale 358 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 173. Tadpoles of members of the Hyla godmani group. A. Hyla godmani, K.U. No. 104185. B. Hyla loquax, K.U. No. 68379. x 3. creamy tan, and the flanks are creamy white. In most males, the anterior part of the chin is suffused with brown. A moderately broad white anal stripe is present in most specimens; likewise, a narrow white line usually is present on the outer edge of the foot. In some indi- viduals small white spots are present on the flanks. Tadpoles: A typical tadpole in develop- mental stage 38 has a total length of 35.5 mm. and a body length of 13.3 mm. The body is as wide as deep. In dorsal profile, the snout is bluntly rounded; in lateral profile, it is sloping from the nostril to the mouth. The eyes are large and directed laterally. The nostrils are directed anterolaterally at a point about two- thirds of the distance from the eyes to the tip of the snout. The opening of the sinistral spiracle is below the midline at a point about two-thirds of the length of the body. The caudal musculature is moderately slender and reaches nearly to the tip of the tail. The cau- dal fins are moderately deep; at midlength of the tail, the depth of the caudal muscula- ture is less than that of either fin. The dorsal fin barely extends onto the body (fig. 173A). In life the body and caudal musculature are pale olive-gray; the caudal fins are trans- parent, and the entire tail is heavily reticulated with black. In preservative the body is pale olive-gray, and the caudal musculature is pale creamy tan. The reticulations on the tail are dark brown. The mouth is anteroventral and moderately small; the width of the mouth is about one- half of the greatest width of the body. The lips are folded laterally, and the median half of the upper lip is bare. Otherwise, the lips are bordered by two or three rows of small papillae; additional papillae are present in the lateral fold. The beaks are moderately slender and bear small serrations. The upper beak forms a broad arch with slender lateral pro- cesses that are moderately expanded distally. The lower beak is broadly V-shaped. There are two upper and three lower rows of teeth; all of the teeth are moderately long and slen- der. The two upper rows are equal in length and extend nearly to the edges of the lips. The second upper row is narrowly interrupted medially. The first and second lower rows are about equal in length to the upper rows, but the third lower row is noticeably shorter and bears smaller teeth. In some specimens, the first lower row is narrowly interrupted medi- ally, whereas in others the first row is com- plete (fig. 174A). Mating Call: The call of Hyla godmani is a moderately high-pitched, pulsed note. The note repetition rate varies from 15 to 23 (mean, 18) notes per minute. The duration of each note is 0.15 to 0.20 (mean, 0.17) of a second. The pulse rate varies from 58 to 62 (mean, 60.2) pulses per second and the dominant frequency varies from 2780 to 3040 (mean, 2920) cycles per second. Three or four harmonics above the dominant frequency and one harmonic below the dominant fre- quency are emphasized in this well-modulated note (pi. 17, fig. 1). 1970 DUELLMAN: HYLID FROGS 359 &£fy®t&m&sx mimmmiti. Fig. 174. Mouths of tadpoles of the Hyla godmani group. A. Hyla godmani, K.U. 104185. B. Hyla loquax, K.U. No. 68379. x 20. Natural History: Hyla godmani inhabits broad-leafed, evergreen forests in areas where there is a noticeable dry season. In the rainy months, frogs of this species congregate around temporary ponds in, or at the edge, of forested areas. At a pond 7 kilometers east- southeast of Cordoba, Veracruz, Mexico, males of this species were observed calling from small trees, bushes, and clumps of grass around the pond, and from vegetation in the pond. Tadpoles were found in a deep weedy pond, where they took refuge amidst the aquatic vegetation. One nearly metamor- phosed individual has a snout-vent length of 12.2 mm. and a tail stub of 5.1 mm. Remarks: Duellman (1964c, p. 455) dis- cussed the taxonomic status of the names Hyla godmani and Hyla rickardsi. Examination of the syntypes of Hyla godmani revealed that the series was composite and consisted of a single specimen of what is now Hyla godmani and eight specimens of Hyla miotympanum Cope. Duellman selected B.M.N.H. No. 1901.12.19.96 from the Misantla, Veracruz, Mexico, as the lectotype. This action relegated Hyla rickardsi Taylor (1939a) to the synon- ymy of Hyla godmani Giinther 1 1901 (1885- 1902)]. Etymology: The specific name godmani is a patronym for Frederick D. Godman, one of the chief contributors to the British Bio- logical Expedition of Mexico and Central Mexico in the Nineteenth Century. Distribution: Hyla godmani occurs on the coastal lowlands of Veracruz and south- ward in the foothills to elevations of about 900 meters in central Veracruz, Mexico (fig. 175). See Appendix 1 for the locality records of the 256 specimens examined. Hyla loquax Gaige and Stuart Hyla loquax Gaige and Stuart, 1934, p. 1 [holo- type, U.M.M.Z. No. 75446 from Ixpuc Aguada, north of La Libertad, El Peten, Guatemala; Laurence C. Stuart collector]. Smith and Taylor, 1948, p. 84. Tay- lor, 1952c, p. 868. Duellman, 1960b, p. 62 [synony- mized Hyla axillamembrana Shannon and Werler, 1955, with Hyla loquax]. Stuart, 1963, p. 36. Duell- man, 1966b, p. 271 [synonymized Hyla stadelmani Schmidt, 1936, with Hyla loquax]. Hyla stadelmani Schmidt, 1936, p. 45 [holotype, M.C.Z. No. 21310 from the Subirana Valley, Departa- mento Yoro, Honduras; Raymond E. Stadelman collec- tor], Hyla axillamembrana Shannon and Werler, 1955, p. 383 [holotype, U.I.M.N.H. No. 67059 (formerly F.A.S. No. 4083) from 8 kilometers south of Lago de Catemaco on San Andres Tuxtla-Minatitlan road, Veracruz, Mexico; John Werler and Jack Reid collec- tors]. Diagnosis: This medium-sized yellow or brown frog with an extensive axillary mem- brane is characterized by a blunt snout, rounded eanthus, and bright red webbing and posterior surfaces of the thighs. Hyla god- mani differs by having a more acuminate snout, angular eanthus, yellow webbing, and tan posterior surfaces of the thighs. Only two other Middle American hylids have red web- bing— Hyla rufitela and H. pseudopuma infu- cata. The former has a green dorsum and a prepollical spine in males and lacks an axillary membrane and red on the thighs. The latter has a blotched dorsal pattern, long snout, and large nuptial excrescences in males and lacks an axillary membrane. Juveniles of Smilisca cyanosticta have red on the posterior surfaces of the thighs but lack an axillary membrane. 360 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 20' 12°- Fic. 175. Distribution of Hi/la aodmani and Hyla loquax. Description: Males of this medium-sized species attain a maximum snout-vent length of 44.7 mm., and females reach 41.7 mm. In a series of 25 males from central El Peten, Guatemala, the snout-vent length is 35.9 to 43.4 (mean, 39.3) mm.; the ratio of tibia length to snout-vent length is 0.472 to 0.537 (mean, 0.510); the ratio of foot length to snout-vent length is 0.410 to 0.454 (mean, 0.435 ) ; the ratio of head length to snout-vent length is 0.290 to 0.327 (mean, 0.307); the ratio of head width to snout-vent length is 0.336 to 0.377 (mean, 0.357), and the ratio of the diameter of the tympanum to that of the eye is 0.512 to 0.694 ( mean, 0.607 ) . Four females from the same locality have snout- vent lengths of 38.8 to 41.7 (mean, 40.5) mm. Specimens from the southern part of the range are slightly larger and have proportion- ately shorter legs and feet and proportionately smaller tympani. For example, in a series of 25 males from Turrialba, Cartago Province, Costa Rica, the snout-vent length is 33.8 to 44.7 (mean, 40.8) mm.; the ratio of tibia length to snout-vent length is 0.436 to 0.519 (mean, 0.482); the ratio of foot length to snout-vent length is 0.404 to 0.458 (mean, 0.424), and the ratio of the diameter of the tvmpanum to that of the eye is 0.383 to 0.590 (mean, 0.496). 1970 DUELLMAN: HYLID FROGS 361 The head is slightly wider than long, but slightly narrower than the body. The top of the head is flat, and the eyes are large and prominent. In dorsal profile, the snout is bluntly rounded, and in lateral profile it is round. The snout is short; the nostrils are slightly protuberant and situated at a point about two-thirds of the distance from the eyes to the tip of the snout. The canthus is round and indistinct; the loreal region is not concave and the lips are thick and not flared. A thin dermal fold extends posteriorly from the orbit, above the tympanum, to a point above the insertion of the arm. The fold covers the upper edge of the tympanum, which other- wise is distinct and separated from the eye by a distance equal to about one-half the diam- eter of the tympanum. The arms are moderately long and robust; an extensive axillary membrane extends to the elbow. Distinct tubercles are absent on the ventrolateral edge of the arm, but a weak transverse dermal fold is present on the wrist. The fingers are moderately short and robust and bear moderately large discs; the width of the disc on the third finger is equal to the diameter of the tympanum. The subarticular tubercles are moderately large and round; none is bifid. The supernumerary tubercles are small and numerous on the proximal seg- ments of each digit. An elevated, tripartite palmar tubercle is present. The prepollex is moderately enlarged, and nuptial excrescences are absent in breeding males. The fingers are about two-thirds webbed ( fig. 172B ) . The webbing extends from the base of the penulti- mate phalanx of the first finger to the distal end of the antepenultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the distal end of the antepenultimate phalanx of the third, from the distal end of the penultimate phalanx of the third to the middle of the penultimate phalanx of the fourth finger. The legs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to the middle of the eye. A strong, transverse dermal fold is present on the heel, and a weak tarsal fold is present dis- tally on the tarsus. The inner metatarsal tu- bercle is moderately small, elliptical, and barely visible from above. A small subcorneal outer metatarsal tubercle is present. The toes are moderately long and bear discs that are only slightly smaller than those on the fingers. The subarticular tubercles are moderately small and conical and the supernumerary tu- bercles are small, subcorneal, and numerous on the proximal segments of the digits. The toes are nearly fully webbed (fig. 172D). The web extends from the base of the disc of the first toe to the base of the second and on to the distal end of the penultimate phalanx of the third, from the base of the disc of the third to the distal end of the penultimate pha- lanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly near the level of the upper surfaces of the thighs. A short, granular anal sheath is pres- ent, and many large granules are present be- low the anal opening. The skin on the upper surfaces is smooth, but under magnification it is minutely corrugated. The skin on the throat and ventral surfaces of the limbs, ex- cept the thighs, is smooth, whereas that on the belly and ventral surfaces of the thighs is granular. The tongue is round or broadly cordiform and shallowly notched behind. Pos- teriorly the tongue is free for about one-fourth of its length. The dentigerous processes of the prevomers are narrowly separated trans- verse ridges between the moderately small, ovoid choanae. Individuals of both sexes have four to six teeth on each process and a total of eight to 12 prevomerine teeth. The average number of teeth in males is 10.3, and in females, 10.0. The vocal slits are long and extend along the inner edge of the lower jaw from the level of the base of the tongue to the angles of the jaws. The vocal sac is me- dian, subgular, and moderately distensible. The general coloration of Hyla loquax is dull reddish brown, yellowish tan, or pale gray above with bright red webs and hidden surfaces of the thighs (pi. 55, fig. 5). Usu- ally at night the dorsum is pale tan or pale reddish brown. Small dark brown or olive- brown flecks usually are present on the back and dorsal surfaces of the limbs; there are no transverse bars on the limbs. The venter is creamy yellow. The axilla, groin, and an- terior and posterior surfaces of the thighs. 362 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 inner surfaces of the tarsi, the first through third toes, and the webbing on the hands and feet are tomato red. The iris is a dull reddish tan. Some individuals change from the color described above to a darker brown with olive- brown irregular markings on the dorsum. By day, most individuals are pale gray, almost white. However, the red on the thighs and webbing, and in the axilla and groin remains constant. In preservative the dorsum varies from uniform dull reddish brown to uniform gray- ish white or these same ground colors with darker flecks. The anterior and posterior surfaces of the thighs, the axilla and groin, and the webbing is creamy yellow. The ven- tral surfaces are creamy white. A thin white anal stripe is present in some individuals, whereas in others there is no anal marking, and in some specimens the entire anal area is white. Tadpoles: A typical tadpole in develop- mental stage 26 has a body length of 11.2 mm. and a total length of 27.5 mm. The body is as deep as wide; the snout is rounded in dor- sal and lateral profiles. The eyes are moder- ately large and directed laterally. The nostrils are directed anterolaterally and situated at a point about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is at the midline about mid- length on the body. The anal tube is short and dextral. The caudal musculature is rela- tively thin and extends nearly to the tip of the tail. The caudal fins are moderately deep, and the dorsal fin extends onto the body. At midlength of the tail the depth of the caudal musculature is slightly less than either the dorsal or ventral fin (fig. 173B). In preservative, the body is pale olive-tan, and the caudal musculature is creamy tan. The fins are transparent; the entire tail is marked with fine brown flecks and reticula- tions. The mouth is anteroventral; its width is equal to about half of the greatest width of the body. The lips are folded laterally, and the median part of the upper lip is bare. The rest of the lips are bordered by one row of large, blunt papillae. In the lateral fold, ad- ditional large papillae are present. The beaks are moderately heavy and bear pointed ser- rations. The upper beak forms a broad arch lacking lateral processes. The lower beak is broadly V-shaped. There are two upper and three lower rows of teeth; all of the teeth are long, pointed, and heavy at the base. The upper tooth rows extend to the edges of the lips, and the second upper tooth row is broad- ly interrupted medially. The lower tooth rows are complete and the third lower tooth row is much shorter than the others (fig. 174B). Mating Call: The call of Hyla loquax consists of a series of notes sounding much like the honking of a goose. Notes are re- peated at intervals of slightly less than one second to about five seconds. The note repe- tition rate varies from nine to 62 (mean, 31) notes per minute. The duration of the notes is 0.05 to 0.16 (mean, 0.095) of a second. The pulse rate is 100 to 150 (mean, 129) pulses per second and the dominant frequency is 2180 to 2430 (mean, 2323) cycles per second (pi. 16, fig. 3). In these poorly modulated notes, there is no emphasized harmonic above the dominant frequency; the energy is rather evenly spread throughout the frequency spec- trum. Natural History: Hyla loquax inhabits lowland, humid tropical forest and breeds in temporary ponds in, or at the edge of the forest. Males sometimes call from bushes or large herbs at the edge of, or in the water. but most frequently males are found on leaves of floating vegetation, such as water lilies. Usually the calling sites are away from shore and in deep water. The eggs are deposited in large gelatinous masses attached to aquatic vegetation; one clutch examined contained about 250 eggs. The tadpoles are exceedingly wary and ap- parently remain in deep water where there is some submerged vegetation. Remarks: Shannon and Werler (1955, p. 383) named Hyla axillamembrana from south- ern Veracruz, Mexico. Duellman ( 1960b, p. 60) demonstrated that axillamembrana (known only from the type specimen) was actually Hyla loquax. The status of Hyla stadelmani Schmidt had been questioned by several authors; Duellman ( 1966b, p. 271 ) reported upon the comparison of freshly pre- served specimens of Hyla loquax and para- 1970 DUELLMAN: HYLID FROGS 363 types of Hyla loquax with the holotype of llijla stadelmani; he concluded that Hyla stadelmani is a synonym of Hyla loquax. The distribution of Hyla loquax in com- parison with that of Hyla godmani offers an apparent excellent example of ecological and geographic replacement. In the northern part of its range, Hyla godmani occurs on the coastal lowlands; southward where its range approaches that of loquax, godmani occurs only in the foothills. In southern Veracruz, where the ranges of the two species are clos- est, Hyla loquax occurs on the lowlands. In Nicaragua and Costa Rica this species occurs on the lowlands, but it seems to reach its greatest abundance in the foothills. Etymology: The specific name is Latin meaning talkative or garrulous and refers to the incessant calling characteristic of this species. Distribution: Hyla loquax occurs in for- ested areas on the Caribbean lowlands and foothills from southern Veracruz, Mexico, southeastward to Costa Rica (fig. 175). In Nicaragua and Costa Rica, the species has been found at several localities at elevations above 1000 meters. See Appendix 1 for the locality records of the 665 specimens examined. The Hyla picta Group Definition: Members of this group are small pond-breeding species; males attain a maximum snout-vent length of 26.0 mm. and females, 31.0 mm. The dorsum is yellow or tan with or without brown flecks, and a white dorsolateral stripe is present. The thighs are deep yellow. The palpebral membrane is clear. The hands are only about one-fourth webbed, and the feet are no more than two- thirds webbed. A tarsal fold and dermal ap- pendages are lacking, but an axillary mem- brane is present. Males have a single, median, subgular vocal sac and horny nuptial excres- cences on the prepollices. The skulls are weakly ossified, and a large frontoparietal fontanelle is present (fig. 176). The nasals are moderately well developed and separated medially. The sphenethmoid is poorly ossi- fied. The squamosal is not in bony contact with the crista parotica, and the anterior arm of the squamosal extends about one-third of Fig. 176. Dorsal view of the skull of Hyla smithii, K.U. No. 59923. X 7. the distance to the maxillary. The quadrato- jugal is in bony contact with the maxillary. The prevomers are poorly ossified, do not ar- ticulate with surrounding bones, and bear teeth (smithii) or not (picta). The medial ramus of the pterygoid does not articulate with the prootic. The known tadpoles have deep, terminally pointed fins and small an- teroventral mouths with two upper and three lower rows of teeth. The mating calls con- sist of a series of rapidly produced, well- modulated, short, high-pitched notes. The haploid number of chromosomes is 12. Composition : Two species ( picta and smithii) comprise the group, which occurs at low to moderate elevations in Mexico and northern Central America. Of the two spe- cies, 2714 preserved frogs, eight skeletons, three lots of tadpoles, and one preserved clutch of eggs have been examined. Comments: The two species certainly seem to be closely related on the basis of external characters and on the nature of the mating calls. Hyla picta is smaller than smithii but has slightly more webbing (fig. 177). The skulls of the two species differ slightly. In picta, the nasals have incomplete maxillary processes and articulate with the sphenethmoid, whereas in smithii maxillary processes are lacking, and the nasals do not articulate with the sphenethmoid. Further- more, minor differences exist in the shapes of the septomaxillaries. Fouquette (1961b) pointed out the alio- 364 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 177. Hands and feet of members of die Hijla picta group. A and C. Htjla picta, K.U. No. 57599. B and D. Hyla smithii, K.U. No. 57702. X 8. patric ranges of the two species and noted that: "The calls of smithii and picta, though basically similar, differ in several important characteristics, to a degree that has been shown to be effective in isolating other sym- patic hylid species." The geographical bar- rier separating the ranges of the two species is the arid Pacific lowland region in the Isth- 1970 DUELLMAN: HYLID FROGS 365 mus of Tehuantepec. Hyla smiihii occurs northwestward from the isthmus on the Pa- cific lowlands of Mexico, whereas Hyla picta is on the Atlantic lowlands. Duellman and Fouquette (1968) pointed out the superficial similarities between mem- bers of the picta and microcephala groups of Hyla. Both are small yellowish tan frogs with similar kinds of mating calls. However, frogs in the microcephala group differ by having no quadratojugal, tadpoles with xiphicercal tails and terminal mouths lacking teeth, and a hap- loid number of 15 chromosomes. In all of these characteristics, frogs of the microcepha- la group seem to be allied with the South American leucophyllata and parviceps groups rather than with the picta group. Although differing greatly in size and in the sound (but not structure) of the mating calls, the frogs in the picta group might be most closely re- lated to the Hyla loquax group on the At- lantic lowlands of Mexico and Central Amer- ica. Frogs in both groups have similar cranial features and larval characteristics. Hyla picta (Gunther) Hylella picta Gunther, 1901 (1885-1902), p. 286 [holotype, B.M.N.H. No. 1947.2.22.62 from Jalapa, Veracruz, Mexico; Mateo Trujillo collector], Kellogg, 1932, p. 180. Hyla picta: Nieden, 1923, p. 284. Smith and Tay- lor, 1948, p. 85. Stuart, 1963, p. 36. Diagnosis: This small yellow frog has a brown lateral stripe, bordered above by a white line, extending from the tip of the snout to the middle of the flank. Numerous brown flecks usually are present on the back, and distinct brown flecks are present on the forearms and shanks. It most closely resembles Hyla smiihii which is larger (males to 26 mm., as opposed to 21.4 mm. in picta) and has pre- vomerine teeth (lacking in picta). Further- more, in smiihii the dark flecks, if present on the forearms and shanks, are indistinct. Other small yellow Middle American hylids having uniformly yellow thighs have irregular dark reticulations on the back (microcephala un- denvoodi and phlebodes), dark chevrons on the back (sartori), a dark hourglass or pair of triangles on the back (ebraccata), a pair of dark paravertebral lines (microcephala micro- cephala), a broad dark lateral stripe extend- ing to the groin ( robertmertensi), or no lateral stripe bordered above by a white line (sumi- chrasti). Description: Males of this small species attain a maximum snout- vent length of 21.4 mm., and females reach 22.1 mm. In a series of 25 males from southern Campeche, Mex- ico, and El Peten, Guatemala, the snout-vent length is 18.6 to 21.4 (mean, 20.2) mm.; the ratio of tibia length to snout-vent length is 0.471 to 0.536 (mean, 0.494); the ratio of foot length to snout-vent length is 0.383 to 0.430 (mean, 0.409); the ratio of head length to snout-vent length is 0.316 to 0.347 (mean, 0.328); the ratio of head width to snout- vent length is 0.321 to 0.355 (mean, 0.340), and the ratio of the diameter of the tympanum to that of the eye is 0.318 to 0.458 (mean, 0.406). Females do not differ from males in proportions. The head is slightly narrower than the body, and the top of the head is flat. In dor- sal and lateral profiles, the snout is rounded. The snout is moderately long; the nostrils are barely protuberant and situated at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is rounded, and the loreal region is nearly flat; the lips are moderately thick and barely flared. A moderately heavy dermal fold ex- tends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance slightly greater than the diameter of the tympanum. The arm is moderately short and slender; a distinct axillary membrane is present. Tu- bercles are lacking on the ventrolateral edge of the forearm, but a weak transverse dermal fold is present on the wrist. The fingers are moderately short and robust and bear small discs; the width of the disc on the third finger is slightly less than the diameter of the tympanum. The subarticular tubercles are large and ovoid; none is bifid. The super- numerary tubercles are low, rounded eleva- tions on the proximal segments of the digits. A low, flat palmar tubercle is present. The prepollex is barely enlarged and in breeding males bears a weak nuptial excrescence. The 366 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 fingers are about one-third webbed (fig. 177A). The webbing is vestigial between the first and second finger, and extends from the base of the penultimate phalanx of the second to the base of the antepenultimate phalanx of the third, and from the distal end of the ante- penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are moderately short and robust; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articula- tion extends to the anterior corner of the eye. A distinct transverse dermal fold is present on the heel, and a low tarsal fold is present dis- tally on the tarsus. The inner metatarsal tu- bercle is low, rounded, and ovoid. No outer metatarsal tubercle is present. The toes are moderately long and slender and bear discs that are as large as those on the fingers. The subarticular tubercles are moderately large and ovoid; the supernumerary tubercles are low and subcorneal. The toes are about three- fourths webbed (fig. 177C). The webbing extends from the base of the penultimate pha- lanx of the first toe to the distal end of the antepenultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the distal end of the penulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. A short, broad anal sheath is present, but tubercles beside the anal opening are lacking. The skin on the throat, belly, and proximal postero- ventral surfaces of the thighs is weakly granu- lar; elsewhere, the skin is smooth. The tongue is cordiform, moderately notched behind, and free posteriorly for about one-fourth of its length. Dentigerous processes are lacking on the prevomers. The choanae are moderately large and ovoid. The vocal slits extend from the midlateral base of the tongue to the an- gles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Hyla picta is pale yellowish tan with dark brown flecks on the dorsum and a dorsolateral light stripe (pi. 55, fig. 4). Usually the dorsal ground color is pale tan. Numerous dark brown flecks or small spots are present on the back, and brown flecks are present on the dorsal surfaces of the forearms, shanks, and feet. A creamy white dorsolateral stripe extends from the tip of the snout, through the nostril and eye, to the middle of the flank. This narrow stripe is bordered by a brown stripe. The ventral surfaces are creamy white, and the vocal sac is yellow. The thighs are uni- formly yellowish tan or yellow with minute tan flecks. The iris is pale bronze. Some individuals when active at night are nearly uniformly pale yellowish tan; in these frogs the dorsolateral stripes are not evident. By day, the pattern has more con- trast. In preservative, the dorsal ground color varies from pale yellowish tan to pale reddish brown. Dark spots on the dorsum and limbs are dark brown. Usually the dorsolateral light stripe is evident and bordered below by a noticeable brown stripe. The ventral surfaces are dull creamy tan. Tadpoles: A small series of tadpoles is available from 5 kilometers south-southwest of Chiltepec, Oaxaca, Mexico. A typical tad- pole in developmental stage 38 has a body length of 9.5 mm. and a total length of 28.0 mm. The body is noticeably deeper than wide; the snout is bluntly rounded in both dorsal and lateral profile. The eyes are mod- erately large, widely separated, and directed laterally. The nostrils are protuberant at a point about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posteriorly below the midline at a point about two-thirds of the distance from the tip of the snout to the posterior end of the body. The cloacal tube is short and dextral. The caudal musculature is moderately slender and extends to the tip of the pointed tail. The fins are deep, and the dorsal fin extends onto the body. At mid- length of the tail, the depth of the caudal musculature is noticeably less than the depth of either fin (fig. 178). The body and tail are pale creamy tan with small brown flecks on the dorsal surfaces of the body and on the caudal fins and muscu- lature. A dark brown stripe extends from the 1970 DUELLMAN: HYLID FROGS 367 Fig. 178. Tadpole of Hijla picta, K.U. No. 104187. X 4. tip of the snout through the eye, which is pale bronze. In preservative the tadpoles are creamy white with scattered brown flecks on the dorsal surfaces of the body and on the fins and caudal musculature. The flecks tend to form vertically oriented bars on the distal half of the caudal musculature. A distinct brown stripe is present from the snout to the eye. The mouth is small and anteroventral. The median part of the upper lip is bare; else- where, the lips are bordered by a single row of moderately large papillae. Lateral folds are present in the lips. The beaks are moderately robust and bear fine serrations. The upper beak is in the form of a broad arch with long slender lateral processes; the lower beak is broadly Y-shaped. There are two upper and three lower rows of teeth; all of the teeth are long. The second upper row is narrowly- interrupted medially and is nearly as long as the first upper row, which extends to the margins of the lips. The lower rows are com- plete; the first and second lower rows are nearly as long as the upper ones, and the third lower row is noticeably shorter (fig. 179). Mating Call: The call of Hyla picta is an insect-like "creek-eek-eek-eek." Notes are pro- duced at a rate of 36 to 94 (mean, 64) notes per minute. The duration of each note varies from 0.033 to 0.075 (mean, 0.043) of a sec- ond, and there are 34 to 63 (mean, 53) pulses per second. The fundamental frequency is the dominant frequency and falls between 1676 and 3320 (mean, 2661) cycles per sec- ond. There are one or two harmonics empha- sized above the fundamental frequency (pi. 19, fig. 1). Natural History: Hyla picta inhabits tropical lowlands characterized by a distinct rainy season, at which time the frogs congre- gate at shallow grassy pools for breeding. Males call from emergent vegetation and from low bushes. During the dry season, individ- uals have been found in bromeliads. The tadpoles have been found in shallow weedy ponds, where the tadpoles seek refuge amidst the dense vegetation. Remarks: For many years this small frog was placed in the genus Hylella, a catch-all assembly of small hylids lacking prevomerine teeth. Etymology: The specific name is Latin, meaning painted, and evidently refers to the small spots on the dorsum. Distribution': Hyla picta ranges through- out the lowlands of Middle America up to elevations of 1300 meters from southern San Luis Potosi, Mexico, to northern Honduras (fig. 180). It does not occur in exceedingly dry areas, such as the northern parts of the Yucatan Peninsula. See Appendix 1 for the locality records of the 774 specimens examined. Fig. 179. Mouth of tadpole of Hyla picta, K.U. No. 104187. x 25. 368 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 20' 16' 90° Fig. 180. Distribution of Hyla picta. Hyla smithii Roulenger Hyla nana Giinther, 1901 (1885-1902), p. 263 [syntypes, B.M.N. H. Nos. 1947.2.12.76-82 from Cuer- navaca, Morelos, Mexico; Herbert H. Smith collector (not Hyla nana Boulenger, 1889, from Colonia Resis- tencia, Chaco, Argentina)]. Hyla smithii Boulenger, 1902b, p. 33 [replacement name for Hi/la nana Giinther, preoccupied]. Smith and Taylor, 1948, p. 85. Hyla eximia (part) : Kellogg, 1932, p. 164. Diagnosis: This small yellow frog has a white dorsolateral stripe extending from the tip of the snout to the mid-flank. The stripe usually is bordered below by a narrow brown line. The dorsum is yellow or tan, with or without small brown flecks. Indistinct brown flecks usually are present on the forearms and shanks. This species is similar to the smaller Hyla picta (males to 21.4 mm., as opposed to 26 mm. in smithii) but has less distinct mark- ings, no wide brown lateral stripe, and pre- vomerine teeth ( lacking in picta ) . Other small yellow Middle American hylids having uniformly yellow thighs have irregular dark reticulations on the back (microcephala un- dencoodi and phlebodes), dark chevrons on the back (sartori), a dark hourglass or pair of triangles on the back (ebraccata)\ a pair of dark paravertebral lines ( microcephala mi- crocephala), a broad dark lateral stripe ex- tending to the groin (robertmertensi), or no lateral stripe bordered above by a white line ( sumichrasti) . Description: Males of this small species attain a maximum snout-vent length of 26.0 mm., and females reach 30.8 mm. In a series of 25 males from La Candelaria, Oaxaca, Mex- ico, the snout-vent length is 23.0 to 26.0 (mean, 24.3) mm.; the ratio of tibia length to snout-vent length is 0.472 to 0.550 (mean, 0.506); the ratio of foot length to snout- vent length is 0.402 to 0.458 (mean, 0.427); the ratio of head length to snout-vent length is 0.303 to 0.333 (mean, 0.312); the ratio of head width to snout- vent length is 0.316 to 0.359 (mean, 0.333), and the ratio of the diameter of the tympanum to that of the eye is 0.407 to 0.560 (mean, 0.480). Six females 1970 DUELLMAN: HYLID FROGS 369 from the same locality have snout-vent lengths of 27.4 to 30.8 (mean, 27.7) mm. They differ from the males by having a slightly larger tympanum; the ratio of the diameter of the tympanum to that of the eye is 0.462 to 0.607 (mean, 0.520). No significant differences in size or proportions are evident from measure- ments of samples throughout the range of the species. The head is slightly narrower than the body, and the top of the head is flat. In dor- sal profile, the snout is acutely rounded; in lateral profile, it is round. The snout is mod- erately long; the nostrils are protuberant at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is slightly angular, and the loreal region is nearly flat. The lips are barely thickened and not flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is only barely distinct and sepa- rated from the eye by a distance slightly less than the diameter of the tympanum. The arms are moderately short and robust; a distinct axillary membrane is present. No tubercles are present on the ventrolateral edge of the forearm, but a thin transverse dermal fold is present on the wrist. The fingers are moderately short and robust and bear medi- um-sized discs; the width of the disc on the third finger is about equal to the diameter of the tympanum. The subarticular tubercles are large and subcorneal; none is bifid. The supernumerary tubercles are low, rounded, and present on the proximal segments of the digits. A flat, usually bifid palmar tubercle is present. The prepollex is only moderately enlarged and in breeding males bears a weak nuptial excrescence. The webbing on the fin- gers is vestigial (fig. 177B). The hind limbs are moderately short and robust; the heels of the adpressed limbs overlap by about one- fourth of the length of the shank. The tibio- tarsal articulation extends to the middle of the eye. A weak transverse dermal fold is present on the heel, and a weak tarsal fold usually is evident distally on the tarsus. The inner metatarsal tubercle is small, flat, and ovoid. An outer metatarsal tubercle is lack- ing. The toes are moderately long and slender and bear discs that are nearly as large as those on the fingers. The subarticular tuber- cles are moderately large and subcorneal, and the supernumerary tubercles are low, flat, and indistinct. The toes are about three-fourths webbed (fig. 177D). The webbing extends from the middle of the penultimate phalanx of the first toe to the distal end of the ante- penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the distal end of the antepenulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. A short, broad anal sheath is present, but tubercles are absent around the anal opening. The skin on the throat, belly, and proximal postero- ventral surfaces of the thighs is granular; else- where, the skin is smooth. The tongue is cordiform, shallowly notched posteriorly, and free behind for about one-third of its length. The dentigerous processes of the prevomers are widely separated, transverse or postero- medially inclined elevations between the moderately large, ovoid choanae. Males have two or three teeth on each process and a total of four to six (mean, 5.1) prevomerine teeth; females have two to four teeth on each pro- cess and a total of five to seven (mean, 6.0) prevomerine teeth. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and greatly distensible. The general coloration of Hijla smithii consists of a pale yellow or tan dorsum with a white or creamy yellow dorsolateral stripe (pi. 55, figs. 1 and 2). When active at night the dorsum usually is pale yellow, and a dis- tinct lateral stripe extends from the tip of the snout, through the eye, to a point on the flanks. The thighs are uniformly yellow or yellowish tan; the belly is white, and the vo- cal sac is bright yellow. The iris is silvery bronze. The coloration by day is highly variable. Some individuals are pale yellowish tan, whereas others are dark yellow or brown. The 370 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 dorsolateral stripe varies from white to pale yellow. In preservative, the dorsum is yellowish tan to pale brown with or without small dark flecks. The dorsolateral stripe is creamy white. Most individuals have some faint dark markings on the shanks and forearms. The belly is white, and the other ventral surfaces are creamy tan. Tadpoles: Some recently hatched tad- poles and metamorphosing young are avail- able, but tadpoles in developmental stages possessing the diagnostic larval characters are lacking. Mating Call: The call of Hyla smithii consists of a series of insect-like chirping notes. Notes are produced at a rate of 60 to 72 (mean, 68) notes per minute. The duration of each note varies from 0.025 to 0.042 ( mean, 0.032) of a second. The pulse rate varies from 30 to 48 (mean, 36) pulses per second. The fundamental frequency varies from 800 to 3100 (mean, 1033) cycles per second, and the dominant frequency, the second harmonic, varies from 1600 to 6200 (mean, 2066) cycles per second (pi. 19, fig. 2). Natural History: Hyla smithii inhabits the subhumid Pacific lowlands of Mexico, characterized by many months of little or no rain. In the rainy season, this small frog is virtually ubiquitous throughout the Pacific lowlands. Males can be heard calling from nearly any temporary pond or roadside ditch. Males usually call from emergent vegetation, but frequently the frogs call from low bushes. Apparently, this species also utilizes small, sluggish streams for breeding, because nu- merous males have been heard calling along such streams. Ry day and in the dry season, these frogs seek shelter in the axils of the leaves of elephant-ear plants (Xanthosoma) . Remarks: Kellogg (1932, p. 165) stated: "The cotypes (R.M. Nos. 1901.12.19.76-82) of Hyla nana Giinther (preoccupied=H;y/a ■smithii Roulenger) are likewise referred to this species \Hyla eximia]. Dr. E. R. Dunn carefully examined a series of specimens of H. eximia with the cotypes of H. nana and concluded that this species was not valid. Conversely, H. VV. Parker, who had previously examined the cotypes wrote that H. smithii seemed to differ from both H. eximia and H. gracilipes." Taylor ( 1936, p. 357 ) redescribed Hyla smithii; since that time no one lias con- fused this species with Hyla eximia. In some samples of Hyla smithii, the pre- vomerine teeth are poorly developed. Oliver ( 1937, p. 6) stated that 14 of the 49 specimens from Colima completely lack vomerine teeth, and that in the remaining 35 the teeth were fully developed on both sides, partially de- veloped on both sides, or absent on one side and present on the other. My observations corroborate those of Oliver, except that I find that most individuals do have dentigerous processes present on both sides. In many individuals the processes are low, and the teeth are completely hidden in the mucosa. Etymology: The specific name is a patro- nym for Herbert H. Smith, who collected the type series. Distribution : Hyla smithii occurs throughout the subhumid Pacific lowlands up to elevations of about 1000 meters from cen- tral Sinaloa to southern Oaxaca, Mexico, and inland in the Ralsas-Tepalcatepec Rasin (fig. 181). See Appendix 1 for the locality records of the 1952 specimens examined. The Hyla miotympanum Group Definition: The members of this group are medium-sized, stream-breeding species; males attain a maximum snout-vent length of 38.4 mm. and females, 51.6 mm. The dorsum basically is pale green, but metachrosis results in the appearance of darker reticulations or mottling on a green or tan background. The anterior and posterior surfaces of the thighs are uniform brown, and the dorsal surfaces of the limbs are not marked by transverse bands. The palpebral membrane is clear. The fingers are no more than one-half webbed, and the feet are less than three- fourths webbed. Dermal fringes and append- ages are absent on the limbs. A tarsal fold is present, but an axillary membrane is lacking. Males have single, median, subgular vocal sacs and horny nuptial excrescences on the pollices. The cranial elements are moderately well ossified; a large frontoparietal fontanelle is present. The sphenethmoid is large and extends anteriorly between the nasals me- 1970 DUELLMAN: HYLID FROGS 371 106° 102° 98° • ! -*" 1 J ' i ' / ^ * \ /r^\, _n \ ' j~' \l N^ '"----'' 'A '■>. w 24° \ ' / i ( \ • i ,J , » i \ s ■* v — ' 24° >n ! v •: J T**V "-' / '" ■' \ / ' ■> f , '-~' ' \ ^L ' -; ' ' / i - / 1 \ S V * J -' ~ s -x \ ^ -* ' / ' / - > > \ c -' i, / ^' ' ^ \ 20° \ 5 i ^ v ~ y \ 20° 16° 0 100 200 N^~^^x / N 9 16° KILOMETERS ^*- i i 106° 102° 98° Fig. 181. Distribution of Hyla smithii. dially (arborescandens) or is small and lies posterior to the nasals (miotympanum). The nasals broadly overlap the sphenethmoid in arborescandens and are narrowly separated from the sphenethmoid in miotympanum (fig. 182). The quadratojugal is absent. The squa- mosal is in bony contact with the crista paro- tica, and the anterior arm of the squamosal extends no more than half of the distance to the maxillary. The medial ramus of the ptery- goid is not in bony contact with the prootic. Prevomerine teeth are present. The tadpoles have moderately long, terminally rounded tails and small mouths with lateral folds and two upper and three or four lower rows of teeth. The mating calls consist of a series of short, rather low-pitched notes. The haploid number of chromosomes is 12 and the diploid number is 24. Composition: Two species (arborescan- dens and miotympanum) comprise the group, which occurs on the Atlantic slopes from Nuevo Leon to Chiapas in Mexico. Of the two species, 1811 preserved frogs, 27 skele- tons, 20 lots of tadpoles, and three preserved clutches of eggs have been examined. Comments: Hyla arborescandens and miotympanum are placed in the same group on the basis of similarities in cranial features and characters of the tadpoles. Externally, the adults of Hyla erythromma closely resem- ble those of miotympanum, but erythromma has a quadratojugal, and the tadpoles of that species have four upper and six lower rows of teeth. Hyla arborescandens might equally well be placed in the Hyla bistincta group, except that the members of the bistincta group that 372 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 most closely resemble arborescandens lack vocal slits and a vocal sac. Hyla arborescan- dens and hazelae merely have external char- acteristics similar to those in members of the Hyla bistincta group, as well as the loss of the quadratojugal; apparently these similari- ties are the result of convergence or parallel- ism and are not indicative of close relation- ship. Hyla miotympanum has a much broader geographic and altitudinal range than does arborescandens, which possibly differentiated from the former at high elevations. The two species occur sympatrically in some areas at elevations of 1800 to 2200 meters. Hyla miotympanum Cope Hyla miotympanum Cope, 1863, p. 47 [syntypes, U.S.N.M. No. 6311 (now lost) and another specimen that apparently was never catalogued (fide Kellogg, 1932, p. 170) from Jalapa and Mirador, Veracruz, Mexico; R. Montes de Oca and Charles Sartorius col- lectors]. Brocchi, 1882, p. 37. Boulenger, 1882a, p. 400. Gunther, 1901 (1885-1902), p. 279. Kellogg, 1932, p. 170. Smith and Taylor, 1948, p. 90. Hyla microtis Peters, 1869, p. 880 [syntypes, Z.M.B. No. 6657 (two specimens) from Puebla, Mexico; Berkenbuseh collector]. Hyla godmani (part) Gunther, 1901 (1885-1902), p. 295 [specimens from Jalapa, Veracruz, Mexico]. Hyla darlingi Smith, Smith, and Werler, 1952, p. 254 [holotype, U. I.M.N. H. No. 21903 from Xico, Veracruz, Mexico; John E. Werler collector]. Diagnosis: This moderately small green Hyla has the fingers about one-third, and the toes about three-fourths webbed. Distinct white stripes are present on the margin of the upper lip, above the anal opening, and on the outer edges of the forearms and feet. There are no transverse bands on the limbs. Hyla miotympanum differs from arborescandens, hazelae, and charadricola by having shorter fingers and toes with more webbing and the anal opening at the upper level of the thighs, instead of at the midlevel of the thighs. Hyla charadricola also differs by having an axillary membrane and by lacking vocal slits. Hyla hazelae differs by having a yellow venter and a bronze canthal stripe. Other predominantly green Middle American Hyla include Hyla uranochroa, which has red eyes and a white spot below the eye, and members of the Hyla eximia group, which have pointed snouts, less Fig. 182. Dorsal views of the skulls of: A. Hyla miotympanum, K.U. No. 59935. B. Hyla arbores- candens, K.U. No. 55605. X 5. webbing, and usually brown markings on the body and limbs. Description: Males of this moderately small species attain a maximum snout-vent length of 38.4 mm., and females reach 51.0 mm. In a series of 20 males from Barranca Metlac, Veracruz, Mexico, the snout-vent length is 26.8 to 31.1 (mean, 28.5) mm.; the ratio of tibia length to snout-vent length is 0.486 to 0.529 (mean, 0.506); the ratio of foot length to snout-vent length is 0.412 to 0.451 (mean, 0.427); the ratio of head length to snout-vent length is 0.283 to 0.333 (mean, 0.316); the ratio of head width to snout- vent length is 0.297 to 0.325 (mean, 0.315), and the ratio of the diameter of the tympanum to that of the eye is 0.353 to 0.485 (mean, 0.409). Five females from the same locality have snout-vent lengths of 36.8 to 43.6 (mean, 39.7) mm. The females differ from the males by having a slightly larger tympanum; the 1970 DUELLMAN: HYLID FROGS 373 ratio of the diameter of the tympanum to that of the eye is 0.462 to 0.579 (mean, 0.519). There is considerable variation in size in vari- ous parts of the range. The largest individuals are from the northern part of the range (Nu- evo Leon, Tamaulipas, and San Luis Potosi ) and from the southeast, in Chiapas. There are no great differences in proportions, except for the noticeably larger tympanum in indi- viduals from Chiapas ( table 37 ) . Throughout the range, females are noticeably larger than males. The head is as wide as the body, and the top of the head is flat. In dorsal profile, the snout is acutely rounded; in lateral profile, the snout slopes from the nostrils to the margins of the lips. The snout is moderately long; the nostrils are barely protuberant at a point about two-thirds of the distance from the eyes to the tip of the snout. The canthus is angu- lar; the loreal region is barely concave, and the lips are moderately thick and barely flared. A moderately heavy dermal fold ex- tends posteriorly from the eye, above the tym- panum, to a point above the insertion of the forelimb. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance equal to the diameter of the tympanum. The arms are moderately short and robust; an axillary membrane is absent. No distinct row of tubercles is present on the ventrolateral edge of the forearm, and the transverse der- mal fold on the wrist is indistinct. The fingers are moderately short and bear rather large discs; the width of the disc on the third finger is equal to the diameter of the tympanum. The subarticular tubercles are moderately small and subcorneal; the distal tubercle on the fourth finger is weakly bifid in some speci- mens. The supernumerary tubercles are mi- nute and indistinct in many specimens. The palmar tubercle is low, diffuse, and bifid. The prepollex is moderately enlarged and in breeding males bears a horny nuptial excres- cence. The fingers are about one-third webbed (fig. 183A). The webbing is ves- tigial between the first and second fingers but extends from the base of the penulti- mate phalanx of the second to the base of the antepenultimate phalanx of the third, and from the middle of the antepenultimate pha- lanx of the third to the distal end of the ante- penultimate phalanx of the fourth finger. The hind limbs are moderately long and slender; the heels of the adpressed limbs barely overlap. The tibiotarsal articulation extends to the anterior corner of the eye. A transverse dermal fold is present on the heel, and a weak tarsal fold extends the full length of the tarsus. The inner metatarsal tu- bercle is low, flat, elliptical, and broadly visi- ble from above. The outer metatarsal tubercle is small and conical. The toes are moderately long and robust and bear discs that are slight- ly smaller than those on the fingers. The sub- articular tubercles are small and subcorneal; the supernumerary tubercles are small, but distinct. The toes are about three-fourths webbed (fig. 183C). The webbing extends from the penultimate phalanx of the first toe to the middle of the penultimate phalanx of the second, from the distal end of the penulti- mate phalanx of the second to the base of the penultimate phalanx of the third, from the middle of the penultimate phalanx of the third to the base of the penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly near the upper level of the thighs. A short, broad anal sheath is present, but distinct tubercles are absent below the anal opening. The skin on the dorsal surfaces is smooth; that on the throat, belly, and proximal pos- teroventral surfaces of the thighs is granular, whereas that on other ventral surfaces is smooth. The tongue is cordiform, shallowly notched behind, and barely free posteriorly. The dentigerous processes of the prevomers are posteromedially inclined elevations be- tween the moderately large, ovoid choanae. Males have two to six (mean, 4.1) teeth on each process, whereas females have four to seven (mean, 5.2) teeth on each process. The vocal slits extend from the posterolateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla miotym- panum consists of a pale green dorsum and a creamy white venter ( pi. 56, fig. 1 ) . Usually, when active at night, the frogs are a pale green above with or without small olive-green 374 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 co W J PQ < (M CO t- o w t^ in CD ■* co in 1 ■— i OCDOoOOCDO-^fOinOCDOOOcOOcSlOcoOO AW in^CO^CO^4^d>^Cl^C0^^^C0^C0^t^ O O CM O ■— lOOiOr^OoOOinOinOCOOCDO-'tfO ^<^_^^}H^-;tl~_irO^-'CO^co — -co — -co ^--co ^--cq — --^^ ooooooooooo J3 OOt~>-<-*CQ»r5r-jl--'-<3; 1> 00 lO lO in lO -0_->— i^C^^im_;in— ;CO_:CO_:05_;Tr_^t^-0 BO C J o J> T3 c/3 •2 S t, e a CO — ' CO " — ' CO — ' CO — ' CO ^-' CO " — CO^CO£-g5CO c '5 bo i ■* ^cn _ t— ~m ,-^t-- ,-^co ^-^m ^m ,-^eo ^m ^m ■r~ - dotOHoioofMooionoNocooHogoi! Measurements f Males of Hyla o ^^cq^co^co^oo^oo^w^M^in^^^^-o SooOcoOc3505oOoO^HOoOooOo50t-ir, CO^^Tf- — -Tf^-'CO^^CO^-'-*" — - tj< ^^ rr ■^ co ' CO ~— 'CO Eh ooooooooooo „g oqOTficor^t^aiinin^gj to . c J in X\ co co _^ in _ co _ N _^ cm ^_ cq ^^ -* ^^ co ,_, ^ P^ P^ S?1^ W ^ C^O^CD^CX^CO^OO^CD c o OJ O05OOOc0O^O^-lO(MOOOoO^OOOc0 'aj - — - J> ti^. co^in^o^co^in^co^^^in^co^cn1^ ■f "> .S^ OTOooooooooocnooooa^ocoor^ooo •?f<^-in^--m--'in~^^--'^-^^^^^'^--'^--'LQ^' H ooooooooooo .2 S3 .3* =r tb Tf in ^i— < ,_^C0 ^^C75 ^^-^ ^-^t-; ,-^ NCOOOntDnCDMlONNMCOMtpcOpcOOOF- < CO *> c 2 «> o " — '-5 ' — 'tp " — 'xt<~-^in"-'cd^-'05"-'o6^^t~-~~'c3v~^ c« CO CO CO oa — i O 2 ! i a 5 c/5 ^ i O c 'n | 4-* c. QJ IS ™ C fl £ « 3 =3 ^ S3 U ^ « i c o 2 o H ^ i o 1 1 1 -s i 00 »_, "3 o 1 g a £ | | m u ?. ^ 5 i— 1 ^ ^2 -^ •• 3 3 3 P SCCcOIOi^v-HI-'S Q Z H H c/5 P- ! 3 0 Cm > ) o> 0 • > > > L 1970 DUELLMAN: HYLID FROGS 375 Fie. 183. Hands and feet of members of the Hyla miotympanum group. A and C. Hyla miotympanum, K.U. No. 57545. B and D. Hyla arborescandens, K.U. No. 86998. X 5. flecks. Normally, the flanks are white with black or brown mottling. The belly and chin are white and the ventral surfaces of the limbs and dorsal surfaces of the first and second fingers and toes are pale yellow. The posterior surfaces of the thighs are dull yel- lowish brown. Individuals from the northern part of the range have a uniformly pale bronze iris with minute black flecks or reticulations. In speci- mens from central Veracruz and from the Sierra de los Tuxtlas in southern Veracruz, the upper part of the iris is a deep reddish bronze and the lower part is a pale yellowish 376 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 bronze. Specimens from the northern slopes of the Chiapan highlands have a uniformly pale reddish bronze iris. Throughout the range most individuals have a distinct white transverse stripe above the anal opening and a narrow white or creamy white stripe on the edge of the upper lip, the ventrolateral edge of the forearm, and the outer edge of the foot. The amount of mottling on the flanks is highly variable. In some individuals, there are a few irregular white flecks or spots on the flanks; these spots are separated by lateral extensions of the dor- sal ground color. In other individuals the white on the flanks forms a distinct stripe, whereas in other individuals the flanks are pale creamy white with scattered brown or black flecks. The pattern on the flanks does not seem to vary geographically. Metachrosis is extreme in this species. Al- though most individuals when active at night are pale green above, some are pale tan with or without fine dark brown or olive-green reticulations. Individuals that are found in bromcliads by day frequently are pale tan with or without darker reticulations on the body. Some individual frogs have been ob- served to span an exceedingly diverse variety of color permutations. For example, one indi- vidual from 3 kilometers southwest of Hua- tusco, Veracruz, in a matter of three hours changed from a pale green to brown with olive-green reticulations and then to dark olive-brown with white flecks (pi. 56, figs. 2-4). Tadpoles: A typical tadpole in develop- mental stage 33 has a body length of 12.1 mm. and a total length of 35.0 mm. The body is ovoid, only slightly wider than deep. The snout in dorsal profile is bluntly rounded, and in lateral profile, the snout is more acutely rounded. The eyes are moderately small, widely separated, and directed dorsolaterals. The nostrils are directed anterolaterally at a point slightly closer to the eyes than to the tip of the snout. The opening of the sinistral spiracle is directed posterodorsally at a point slightly below the midline at about midlength of the body. The anal tube is moderately short and dextral. The caudal musculature is moderately heavy and extends nearly to the tip of the rounded tail. At midlength of the tail, the musculature is equal to the depth of the ventral fin and slightly shallower than the depth of the dorsal fin, which does not extend onto the body (fig. 184A). The body is dark brown, somewhat paler laterally; the venter is bluish gray. The tail is creamy tan with dark brown pigment proxi- mally on the musculature and along the dorsal edge of the musculature nearly to the tip of the tail. Small black flecks are present on the dorsal fin and on the posterior one-third of the ventral fin. In preservative, the body is dark brown; the caudal musculature is creamy tan with a dark brown dorsal edge. The fins Fie. 184. Tadpoles of members of the Hyla miotympanum group. A. Hyla miotympanum, K.U. No. 59994. B. Hyla arbovescandem, K.U. No. 87605. X 4. 1970 DUELLMAN: HYLID FROGS 377 Fig. 185. Mouths of tadpoles of the Hyla mio- tympanum group. A. Hyla miotympanum, K.U. No. 59994. B. Hyla arborescandens, K.U. No. 87605. X 15. are transparent with scattered small brown flecks. The mouth is ventral and moderately small; its width is equal to about one-half of the greatest width of the body. Lateral folds are present. The median part of the upper lip is bare, but the rest of the mouth is bordered by a single row of blunt papillae. Additional papillae are present in the lateral folds. The beaks are moderately well developed and bear blunt serrations. The upper beak is in the form of a broad arch with long, slender lateral processes; the lower beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows are equal in length, and the second upper row is narrowly interrupted medially. The three lower rows are approximately the same length, but slightly shorter than the upper rows; the first lower tooth row is interrupted medially in some specimens (fig. 185A). A developmental series of eggs and tad- poles was obtained on the south slope of Volcan San Martin Tuxtla in southern Vera- cruz, Mexico. A clump of about 120 eggs was attached to the lee side of a rock in a small stream on August 9, 1960. The eggs hatched on August 11. The following de- scription of embryonic and larval develop- ment is based on that clutch of eggs, tadpoles hatched from those eggs, and tadpoles ob- tained in the same stream. The diameter of the eggs, exclusive of membranes, in developmental stage 2 is 2.10 to 2.38 (mean, six eggs, 2.25) mm. The di- ameter of the fertilization membrane is 3.36 to 5.18 (mean, 4.32) mm., and the diameter of the envelope is 6.3 to 9.8 (mean, 7.70) mm., whereas the diameter of the animal pole is 1.22 to 2.10 (mean, 1.49) mm. In these eggs, the animal pole is dark brown, the gray crescent is clearly visible, and the jelly is clear. Eggs in developmental stage 3 have a well-defined cleft and are uniformly medium brown. The diameter of five eggs, exclusive of membranes is 2.52 to 2.66 (mean, 2.60) mm. In 10 eggs in developmental stage 17, the length of the body is 2.87 to 3.47 (mean, 3.18) mm. In most of these embryos the tail bud is well formed. The body is dorsally arched; this is most prominent in the larger embryos. The gill plates are conspicuous but are not divided into visceral arches. The oral suckers are well developed; the optic vesicle is barely visible. The stomodeal cleft is just beginning to invaginate, but there is no indication of proctodeal invagination. The entire egg is uniformly medium to dark brown, except for a paler area on the anteroventral part of the yolk sac. In 10 hatchlings (developmental stage 19) the body length is 4.8 to 5.1 (mean, 4.92) mm. and the total length is 7.4 to 8.5 (mean, 8.11 mm. In these hatchlings the yolk sac is evident but greatly reduced in size. The gill filaments do not seem to be completely de- veloped. The oral suckers are bifid, and the stomodeal cleft is deeply invaginated. The tail is well developed; the dorsal fin extends almost to the midpoint of the body and is deepest on the posterior one-third of the tail, whereas the ventral fin is deepest anteriorly. The tadpoles are dark brown, but discrete pigment cells are not evident; the cornea and fins are opaque. Ten tadpoles in developmental stage 25 have body lengths of 7.7 to 9.6 (mean, 8.76) 378 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 mm. and total lengths of 19.6 to 26.5 (mean, 23.0) mm. In these tadpoles the mouth is fully developed, although in some individuals the maximum extent of the outer tooth rows has not been attained. The coloration is fully developed, except for pigmentation on the tail. Five tadpoles in developmental stage 30 have body lengths of 11.5 to 12.7 (mean, 12.2) mm. and total lengths of 30.0 to 36.3 (mean, 33.37) mm. Tadpoles in this stage have fully developed caudal pigmentation consisting of coalesced pigment cells forming venated or branching patterns amidst other discrete cells. Three tadpoles in developmental stage 42 have body lengths of 12.2 to 12.9 (mean, 12.6) mm. In these tadpoles, the belly and ventral surfaces of the thighs are granular and unpigmented, the digital pads are mod- erately well developed, and absorbtion of the tail has begun. The larval mouth parts have been lost, except for some lateral pa- pillae. Three completely metamorphosed young have snout- vent lengths of 14.1 to 16.7 (mean, 15.2) mm. The dorsum is uniform green and the venter is white. Mating Call: The calls of Hijla mio- tympanum are highly variable within and be- tween populations. Recordings were made at four different localities throughout the range (table 38). The call of this species can best be described as a series of moderately short notes that are rather squeaky. Monophasic notes are characteristic of all the samples, except that from Volcan San Martin in south- ern Veracruz; individuals from there pro- duced biphasic notes. The other principal variables in the calls are the note repetition rate and duration of the notes, which, of course, are correlated. Individuals from Bar- ranca Metlac, Veracruz, consistently pro- duced only one note per call group; these notes had durations of 0.18 to 0.40 (mean, 0.29) of a second and were consistently long- er than those produced by frogs at other localities. The dominant frequency, although variable within each sample, is not signifi- cantly different between populations. The calls of Hyla miotympanum are poorly modu- lated; consequently, the fundamental fre- quency cannot be ascertained with any degree of accuracy (pi. 15, fig. 1). Natural History: Throughout most of its range, Hyla miotympanum occurs in cloud forests, where it is active most, if not all, of the year. I have observed mating behavior and heard males calling in every month of the year except October and November, months in which I have not been in the range of Hyla miotympanum. Despite the non-seasonal ac- tivity of this species, most breeding appar- ently takes place in the dry season (Decem- ber through April ) . At that time of the year, males call along small mountain streams in the cloud forests (pi. 11). The eggs are de- posited in the streams, either attached to the lee sides of rocks or to vegetation in the water (fig. 186). During the rainy season, streams that were utilized by Hyla miotympanum in the dry season often are roaring torrents, ap- parently uninhabitable by the adults or tad- poles of this frog. In the rainy reason, Hyla miotympanum has been observed calling along small seepages and small rivulets, which apparently are much less affected by the rains than are the larger streams. Fig. 186. Eggs of Hyla miotympanum. X 2. 1970 DUELLMAN: HYLID FROGS 379 00 CO W J 03 < s e a. s O a: c « a Oh a U 60 e c o > V IB, a, aj 1h bO O a> o c o 'P S 0, ~0 C : a ■1 O 0) .£ ce—Z si a; ^ a— a O u & o i— ( cm CM "--' CM O C O CM m -— . c C I in CO CD h cm Cm o C o 2 o o t> o t^ cq lo in o CM ,-.© 00 iri <0 CM Q£j CM [-_ <-N 1/2 to . 9 3 T § _«j o CT> 05 ^>-h ^m ^ lO CO W f, t-^ CO r-1 in <>) ^ oo o •*t< -^ .— i -^- in "-^ l> CM CD ^H CM ^ CM CO ■4 in CO "* CM ■— ' I-H ■— 1 i-H CO :cm CD 2 S3 a -a a o S S a o S a J U 3 z o o o — 3 00 - a a 03 2 C8 00 c "o > > 380 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 By clay, Hyla miotympanum usually is se- creted in bromeliads, or in elephant-ear plants. The frogs have been observed to crawl out of the bromeliads at dusk and down the trees, through bushes, and sometimes onto the ground before reaching their calling sites on low vegetation or rocks along the streams. One individual was observed to utilize the same bromeliad and the same calling site for three consecutive days and nights. The tadpoles develop in the mountain streams, where they inhabit quiet pools and take refuge amidst detritus on the bottom of the pool or beneath rocks. Some tadpoles have been observed clinging to rocks in the swiftest parts of the streams, but the tadpoles of Hyla miotympanum do not appear to be highly adapted for swift water. Remarks: Duellman (1964c, p. 455) showed that the type series of Hyla godmani Giinther was composite; he selected B.M.N.H. No. 1901.12.19.96 from Misantla, Veracruz, as the lectotype of godmani. That specimen is the same as the frogs that previously had been referred to as Hyla rickardsi Taylor. The other specimens in the type series (B.M.N.H. Nos. 1901.12.19.88-95) are from Jalapa, Vera- cruz, and are representatives of Hyla mio- tympanum. Peters (1869, p. 880) named Hyla micro- tis from "Puebla, Mexico." The two syntypes (Z.M.B. No. 6657) are indistinguishable from Hyla miotympanum. One individual is a male having a snout-vent length of 34.9 mm., and the other is a female with a snout-vent length of 38.1 mm. Smith, Smith, and Werler (1952, p. 254) named Hyla darlingi from Xico, Veracruz. This specimen is a moderately large (snout- vent length, 40.2 mm.) female of Hyla mio- tympanum; it differs in no morphological char- acters from females of that species. The considerable variation in the mating call of Hyla miotympanum throughout its range, together with the coloration of the iris, provide a worthwhile problem for investiga- tion. Perhaps, Hyla miotympanum as here recognized, is composite; however, on the basis of my own rather extensive field obser- vations and the examination of many pre- served specimens, I have been unable to de- tect the presence of more than one species. Etymology: The specific name, miotym- panum, is derived from the Greek meion, a diminutive prefix and the Greek tympanon, meaning drum; the name, meaning a little drum, refers to the small tympanum. Distribution: Hyla miotympanum occurs in cloud forests on the Atlantic slopes of the Sierra Madre Oriental at elevations from 100 to 2280 meters from central Nuevo Leon to central Veracruz, Mexico. Populations also oc- cur on the northern slopes of the Chiapan highlands and in the Sierra de los Tuxtlas in southern Veracruz, where the species de- scends to an elevation of 370 meters (fig. 187 ) . Three localities are highly questionable. Two specimens from Aeapulco, Guerrero (one in F.M.N.H. and one in U.I.M.N.H., both formerly a part of the E.H.T.-H.M.S. collection) supposedly were collected at that locality by Edward H. Taylor. The specimens definitely represent Hyla miotympanum, but on the basis of the environment at Aeapulco and the extensive collecting done there with- out revealing the presence of this species, I regard these specimens as having erroneous data. Three specimens in the U.S.N.M. are labeled as having come from Tehuantepec, Oaxaca. These specimens are part of a ship- ment received from Francis Sumichrast shortly after he had moved to Oaxaea from Mirador, Veracruz, a locality where Hyla miotympanum occurs in abundance. The specimens on which Peters based his descrip- tion of Hyla microtis supposedly originated from Puebla, Mexico, and other species in the same collection have been thought to have originated from Izucar de Matamoros in that state; it is highly unlikely that Hyla miotym- panum occurs in that arid upper balsas basin in which Izucar de Matamoros is located. See Appendix 1 for the locality records of the 1663 specimens examined. Hyla arborescandens Taylor Hyla arborescandens Taylor, 1939a, p. 388 [holo- type, U.I.M.N.H. No. 25045 (formerly E.H.T.-H.M.S. No. 3135) from 3 kilometers southwest of Aeultzingo, Veracruz, Mexico; Edward H. Taylor and Hobart M. Smith collectors]. Smith and Taylor, 1948, p. 91. Ih/la forbesi Taylor, 1940d, p. 513 [holotype, U.I.M.N.H. No. 25048 (formerly E.H.T.-H.M.S. No. 2276 ) from 3 miles southwest of Aeultzingo, Veracruz, 1970 DUELLMAN: HYLID FROGS 381 94° 24°- 20° KILOMETERS Fig. 187. Distribution of Hyla miotympanum. Mexico; Dyfrig McH. Forbes collector]. Smith and Taylor, 1948, p. 88. Diagnosis: This moderate-sized green Hyla has the fingers about one-fourth, and the toes about two-thirds, webbed. The anal opening is directed posteroventrally at the midlevel of the thighs. The species differs from miotympanum by having less webbing and by lacking distinct white stripes on the margin of the lips, above the anal opening, and on the outer edges of the forearms and feet. Furthermore, in miotympanum the anal 382 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 opening is directed posteriorly at the upper level of the thighs. Ihjla hazelae differs by having much less webbing and a yellow belly. Ihjla arborescandens resembles certain mem- bers of the Hijla bistincta group, principally charadicola, robertsorum, and siopela; it dif- fers from all of these by having vocal slits. Description: Males of this medium-sized species attain a maximum snout-vent length of 37.6 mm., and females reach 51.6 mm. In a series of 23 males from the north slope of the Sierra de Juarez, Oaxaca, Mexico, the snout-vent length is 31.9 to 35.5 (mean, 33.3) mm.; the ratio of tibia length to snout-vent length is 0.472 to 0.520 (mean, 0.495); the ratio of foot length to snout-vent length is 0.432 to 0.486 (mean, 0.454); the ratio of head length to snout-vent length is 0.319 to 0.350 (mean, 0.331); the ratio of head width to snout-vent length is 0.318 to 0.365 (mean, 0.339), and the ratio of the diameter of the tympanum to that of the eye is 0.421 to 0.600 (mean, 0.480). Four females from the same locality have snout-vent lengths of 42.0 to 51.6 (mean, 45.1) mm. Females differ from males by having a proportionately larger tympanum; the ratio of the diameter of the tympanum to that of the eye in females is 0.469 to 0.617 (mean, 0.542). Specimens from farther north have relatively longer legs and feet and small- er tympani. In a series of 18 males from Pan de Olla, Veracruz, the ratio of tibia length to snout-vent length is 0.513 to 0.562 (mean, 0.535); the ratio of foot length to snout-vent length is 0.481 to 0.517 (mean, 0.494), and the ratio of the diameter of the tympanum to that of the eye is 0.357 to 0.500 (mean, 0.425). The head is as wide as the body, and the top of the head is flat. In dorsal profile, the snout is bluntly rounded; in lateral profile, it is truncate and posteroventrally inclined. The snout is moderately long; the slightly protu- berant nostrils are situated at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is round, but distinct; the loreal region is barely con- cave, and the lips are moderately thick and barely flared. A heavy dermal fold extends posteriorly from the eye, above the tympan- um, and downward to a point above the in- sertion of the arm. The fold obscures the upper edge of the tympanum, which other- wise is distinct and separated from the eye by a distance equal to half again the diameter of the tympanum. The arms are moderately long; the upper arm is slender, whereas the forearm is mod- erately robust. An axillary membrane is lack- ing. A few low tubercles are present on the ventrolateral edge of the forearm, and a weak dermal fold is present on the wrist. The fingers are moderately long and robust and bear large discs; the diameter of the disc on the third finger is slightly greater than the diameter of the tympanum. The subarticular tubercles are large and flat; the distal tubercle on the fourth finger is weakly bifid in some specimens. The supernumerary tubercles are low and indistinct; they are present only on the proximal segments of the digits. A distinct bifid or partially trifid palmar tubercle is present. The prepollex is greatly enlarged and in breeding males bears a spinose nuptial excrescence. The fingers are about one-fourth webbed (fig. 183B). The webbing is vestigial between the first and second fingers, and ex- tends from the distal end of the antepenulti- mate phalanx of the second to the base of the antepenultimate phalanx of the third and on to the distal end of the antepenultimate pha- lanx of the fourth finger. The hind limbs are moderately short and slender; the heels of the adpressed limbs overlap by about one- fourth of the length of the shank. The tibio- tarsal articulation extends to the middle of the eye. A distinct transverse dermal fold is present on the heel, and a weak tarsal fold extends the full length of the tarsus, but the tarsal fold is evident only distally in many specimens. The inner metatarsal tubercle is low, flat, elliptical, and partly visible from above. The outer metatarsal tubercle is small and subcorneal. The toes are long and slender and bear discs that are only slightly smaller than those on the fingers. The subarticular tubercles are large and flat and the super- numerary tubercles are low and subcorneal. The toes are about two-thirds webbed (fig. 183D). The webbing extends from the base of the penultimate phalanx of the first toe to the distal end of the penultimate phalanx of the second, from the middle of the penulti- mate phalanx of the second to the middle of the antepenultimate phalanx of the third. 1970 DUELLMAN: HYLID FROGS 383 from the base of the penultimate phalanx of the third to the base of the penultimate pha- lanx of the fourth and on to the base of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally near the midlevel of the thighs. A short, narrow anal sheath is present; tubercles are lacking below the anal opening. The skin on the throat, belly, and ventral surfaces of the thighs is granular; elsewhere, the skin is smooth. The tongue is eordifonn, very shal- lowly notched posteriorly and not free behind. The dentigerous processes of the prevomers are high, narrowly separated, transverse or posteromedially inclined elevations between the large ovoid choanae. Males have four to seven (mean, 5.4) teeth on each process, and females have five to eight (mean, 6.3) teeth on each process. The vocal slits extend from the midlateral base of the tongue to the an- gles of the jaws. The vocal sac is single, me- dian, subgular. and moderately distensible. The general coloration of Hyh arbores- candens varies from nearly uniform green above to tan or brown with olive-brown or olive-green mottling or reticulations (pi. 57, figs. 3 and 4). At night the dorsum usually is dull green or olive-green. The belly is white or pale yellow, and the ventral surfaces of the hind limbs are dull yellow. In breed- ing males, the vocal sac is dull yellow. The posterior surfaces of the thighs are dull yel- lowish brown. By day, individuals usually are tan or medium brown dorsally; in some specimens, the flanks are pale green. The iris is dull bronze, usually heavily flecked with black. In some specimens, a faint creamy- white anal stripe or pair of spots are present; white stripes along the chin and edges of the forearms are absent, but in some individuals a faint pale tan stripe is present on the outer edge of the tarsus. Also, in some individuals a distinct olive-tan or dull bronze colored stripe is present on the canthus and supra- tympanic fold. In preservative, the dorsum is dull bluish purple or dull brown with black or dark brown flecks and reticulations. The flanks usually are a paler color, and the ventral sur- faces are dull creamy yellow. A few dark flecks are present on the chin in many males. The posterior surfaces of the thighs are dull brown, and the webbing on the feet is gray- ish tan. Tadpoles: A tadpole in developmental stage 25 has a body length of 8.2 mm. and a total length of 28.4 mm. The body is ovoid and only slightly wider than deep. In dorsal profile, the snout is bluntly rounded; in lateral profile, it is round. The eyes are small, widely separated, and directed dorsolaterally. The nostrils are directed anterolaterally at a point about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed dorsally on the midline at a point about two-thirds of the distance from the snout to the posterior edge of the body. The anal tube is moderately long and dextral. The caudal musculature is moder- ately robust and it extends nearly to the tip of the rounded tail. The caudal fins are deep- est posteriorly and the dorsal fin does not ex- tend onto the body. At midlength of the tail, the depth of the caudal musculature is equal to the depth of the dorsal fin and slightly greater than the depth of the ventral fin (fig. 184B). In preservative, the body is dull brown, and the caudal musculature is pale creamy tan with dark brown streaks on the proximal dorsal surface. The fins are transparent. The mouth is ventral and moderately large; its width is equal to about two-thirds the greatest width of the body. Deep lateral folds are present. The mouth is completely bordered by a single row of moderately large, blunt papillae. Additional papillae are pres- ent in the lateral folds. The beaks are well developed and bear moderately long, pointed serrations. The upper beak is in the form of a broad arch with long lateral processes. The lower beak is broadly V-shaped. There are two upper and four lower rows of teeth. The two upper rows are long, and the second upper row is narrowly interrupted medially. The lower rows are complete, and the fourth lower row is noticeably shorter than the others, which are only slightly shorter than the upper rows (fig. 185B). Mating Call: The call of Hijla arbores- candens consists of a series of low-pitched, pulsed notes. The duration of each call group varies from 15 to 18 seconds and contains from 16 to 22 notes. The note repetition rate varies 584 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 from 64 to 73 notes per minute, and the dura- tion of the notes varies from 0.22 to 0.28 of a second. In one recording, in which the data could be obtained accurately, the pulse rate was 80 pulses per second, the fundamental frequency was 74 cycles per second, and the dominant frequency was 2072 cycles per sec- ond (pi. 15, fig. 2)' Natural History: Hijla arborescandens inhabits cloud forests and cool montane pine- oak forests, where the species lives in the immediate vicinity of small streams. Males have been heard to call throughout most of the year, and the breeding season in this spe- cies probably is lengthy. Although some in- dividuals can be found on rocks in and along, or vegetation over, streams by day, the usual day-time retreat of Hyla arborescandens is in bromeliads growing on trees near the streams. Tadpoles have been found in quiet pools in rocky streams. When disturbed, they seek refuge beneath rocks or in the detritus at the bottom of the pool. Remarks: Examination of the holotype of Hyla forbesi Taylor (U.I.M.N.H. No. 25048) reveals that this specimen is nothing more than a female of Hyla arborescandens. The large females of this species are easily confused with members of the Hyla bistincta 98° 96° 98c 96° Fig. 188. Distribution of Hyla arborescandens. group, especially Hyla robertsorum and sio- pela. Hyla hazelae is easily confused with Hyla arborescandens, especially on the basis of preserved specimens. The former has a pro- portionately larger head and a distinct can- thai stripe. The major differences between the two species are evident in the cranial osteology and in the mating calls (see ac- count of Hyla hazelae). Etymology: The specific name is derived from the Latin arbor, meaning tree, and the genitive of the Latin scando, meaning to climb; literally, the name means a climber of trees. Distribution: Hyla arborescandens oc- curs in cloud forests and pine-oak forests at elevations of 1600 to 3100 meters in the Sierra Madre Oriental from northern Puebla to cen- tral Oaxaca, Mexico (fig. 188). See Appendix 1 for the locality records of the 198 specimens examined. The Hyla hazelae Group Definition: The members of this group are small, stream-breeding species; males at- tain a maximum snout-vent length of 38.6 mm., and females reach 37.8 mm. (females of largest species unknown). The dorsum is uniform green or mottled green and brown, and the venter is pale yellow or white with bold mottling. The palpebral membrane is clear. The webbing on the hand is vestigial, and the feet are only about one-half webbed. Dermal fringes and appendages are lacking on the limbs, and an axillary membrane is absent. The tympanum is distinct and about one-half of the size of the eye. Males have nuptial excrescences, vocal slits, and a single, large, median, subgular vocal sac. The cra- nial elements are moderately well ossified. An ovoid frontoparietal fontanelle exists between the moderately developed frontoparietals (fig. 189). The sphenethmoid is large, trun- cate, or notched anteriorly, and extends far anteriorly between the large nasals. The na- sals are separated medially and in bony con- tact with the sphenethmoid (hazelae) or not (thorectes). The quadratojugal is reduced to a small spur or is absent; the squamosal is not in bony contact with the crista parotica, and the anterior arm of the maxillary extends only 1970 DUELLMAN: HYLID FROGS 385 about one-half of the distance to the maxil- lary. The medial ramus of the pterygoid does not have a bony articulation with the prootic. Prevomerine teeth are present. The known tadpoles have small ventral mouths, complete- ly bordered by papillae and bearing two up- per and three lower rows of teeth. The calls consist of short moderately low-pitched notes that are produced singly or in pairs. The number of chromosomes is unknown. Composition: Two species (Hyla hazelae and thorectes) comprise this group, which is endemic to the mountains of Oaxaca, Mexico. Forty-one preserved frogs, two skeletons, three lots of tadpoles, and three preserved clutches of eggs have been examined. Comments: The two species placed in this group are noticeably different in colora- tion but possess certain common external and osteological characters that distinguish them from other Middle American hylids. The combination of large hands with vestigial webbing, half-webbed feet (fig. 190), and presence of a tympanum are external features which separate these species from other small stream-breeding Mexican Hyla. Furthermore, both species have small, relatively narrow tongues and large tubercles below the anal opening. The nature of the nasals and sphen- ethmoid are unique among the northern Mid- dle American hylids. Members of this group seem to be some- what intermediate between Hyla arborescan- Fig. 189. Dorsal view of the skull of Hyla hazelae, K.U. No. 100968. X 5. dens and members of the Hyla bistincta group. Hyla hazelae and thorectes apparently differentiated from one another through iso- lation by the xeric Valley of Oaxaca; the for- mer occurs on Cerro San Felipe north of the valley, and the latter inhabits cloud forests on the southern slopes of the Sierra Madre del Sur south of the valley. Hyla hazelae Taylor Hyla hazelae Taylor, 1940c, p. 385 [holotype, F.M.N. H. No. 100047 (formerly E.H.T.-H.M.S. No. 16262) from Cerro San Felipe, 15 kilometers north- east of Oaxaca, Oaxaca, Mexico; Edward H. Taylor collector]. Smith and Taylor, 1948, p. 90. Diagnosis: This moderately small, stream- breeding species has a green dorsum, pale yellow belly, and a bronze canthal stripe. It can be distinguished from all other green Middle American Hyla by having vestigial webbing on the hand and the feet only about half webbed. It differs from thorectes by lacking a mottled dorsum and heavily blotched throat and belly. Hyla uranochroa and Ptychohyla schmidtorum chanudae are the only other Middle American hylids re- sembling hazelae in coloration; both differ by having a white spot below the eye and by having more webbing. Description: Males of this moderately small species attain a maximum snout-vent length of 3S.6 mm.; females are unknown. In a series of seven males from Cerro San Felipe, Oaxaca, Mexico, the snout-vent length is 35.0 to 38.6 (mean, 36.8) mm.; the ratio of tibia length to snout-vent length is 0.461 to 0.494 (mean, 0.480); the ratio of foot length to snout-vent length is 0.407 to 0.457 (mean, 0.440); the ratio of head length to snout-vent length is 0.304 to 0.327 (mean, 0.312); the ratio of head width to snout-vent length is 0.325 to 0.340 (mean, 0.331), and the ratio of the diameter of the tympanum to that of the eye is 0.419 to 0.587 (mean, 0.472). The head is as wide as the body, and the top of the head is flat. In dorsal profile, the snout is bluntly rounded, and in lateral pro- file it is round. The snout is moderately short, and the nostrils are barely protuberant at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is rounded; the loreal region is barely 386 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fie. 190. Hands and feet of members of the Hyla hazelae group. A and C. Hijla hazelac, K.U. No. 100969. B and D. Hyla thorectcs, K.U. No. 100951. X 5. 1970 DUELLMAN: HYLID FROGS 387 concave, and the lips are thick and barely flared. A heavy dermal fold extends posterior- ly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is only barely distinct. The tympanum is separated from the eye by a distance equal to twice the length of the diameter of the tympanum. The arms are moderately long and slender; an axillary membrane is absent. A row of low tubercles is present on the ventrolateral edge of the forearm, and a distinct dermal fold is present on the wrist. The fingers are moder- ately long and slender and bear medium- sized discs; the width of the disc on the third finger is slightly greater than the diameter of the tympanum. The subarticular tubercles are moderately large and subcorneal; none is bifid. The supernumerary tubercles are large and subcorneal. A large, triangular palmar tubercle is present. The prepollex is greatly enlarged and in breeding males bears a nup- tial excrescence. The fingers are barely webbed (fig. 190A). The legs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articula- tion extends to the posterior corner of the eye. A weak tarsal fold is evident on the posterior half of the tarsus. The inner meta- tarsal tubercle is elongately elliptical, flat, and visible from above. An outer metatarsal tubercle is absent. The toes are moderately long and slender and bear discs that are somewhat smaller than those on the fingers. The subarticular tubercles are moderately large and subcorneal; the supernumerary tu- bercles are large and distinct. The toes are about one-half webbed (fig. 190C). The webbing extends from the base of the penulti- mate phalanx of the first toe to the distal end of the antepenultimate phalanx of the sec- ond, from the middle of the penultimate pha- lanx of the second to the base of the ante- penultimate phalanx of the third, from the base of the penultimate phalanx of the third to the middle of the antepenultimate phalanx of the fourth and on to the middle of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally at the midlevel of the thighs. A distinct anal sheath is present. A large tubercle and several smaller tubercles are present ven- trally on each side of the anal opening. The skin of the dorsum and ventral surfaces of the arms and legs, except thighs, is smooth; that on the throat, belly, and ventral surfaces of the thighs is strongly granular. The tongue is elongately elliptical, emarginate posteriorly, and barely free behind. The dentigerous pro- cesses of the prevomers are large, posterome- dial^ inclined elevations between the mod- erately small, ovoid choanae. There are four or five teeth on each process. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is large, median, single, and subgular. The general coloration of Hyla hazelae is green above and pale yellow below (pi. 57, fig. 1 ) . The dorsum is dark green with pale green flecks. Distinct dull bronze stripes are present on the upper lip, the edge of the can- thus, and on the supratympanic fold. The flanks are mottled dark brown and creamy white. The anterior and posterior surfaces of the thighs vary from purplish brown to orange-brown. The anal stripe and anal tu- bercles are white. The belly is creamy yel- low; the distended vocal sac is pale yellow, whereas when collapsed it is greenish tan with yellow flecks. The iris is deep bronze with black reticulations. In preservative, the dorsum varies from purplish brown to dull bluish gray, usually distinctly marked with pale bluish white flecks. The flanks are dull brown with creamy white flecks and reticulations, and the venter is creamy yellow. The labial, canthal, and supratympanic stripes are dull brown in freshly preserved specimens, whereas in older specimens, these stripes are not evident. The anal stripe and anal tubercles are white in all specimens. Tadpoles: The tadpoles of this species are unknown. Mating Call: Two recordings of this spe- cies are available. The call consists of indi- vidual notes or short groups of notes repeated quickly. One individual produced 23 notes in one minute. One or two notes were pro- duced most frequently in this series of notes, but the frog produced one set of three and one set of four notes. Another individual pro- 388 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 duced 28 notes in one minute with one or two notes in each group; groups of two were most common. The duration of each note varies from 0.5 to 0.7 of a second, and the pulse rate varies from 120 to 140 pulses per second. The dominant frequency varies from 1800 to 1850 cycles per second (pi. 16, fig. 2). Natural History: Taylor ( 1940c, p. 385) found individuals of this species along a small stream on Cerro San Felipe, Oaxaca. In Au- gust, 1966, I found individuals calling from bushes over and near small streams in pine- oak forests on the slopes of Cerro San Felipe. Remarks: It is possible that some of the specimens referred to Hyla arborescandens, that were collected on Cerro San Felipe, ac- tually are Hyla hazelae. Most of these speci- mens are sufficiently darkened by preserva- tive, that the diagnostic stripes cannot be ascertained. Etymology: The specific name is a pat- ronym for Mrs. Hazel Roberts, who aided Edward H. Taylor in collecting amphibians and reptiles on Cerro San Felipe. Distribution: Hyla hazelae is known only from elevations in excess of 2300 meters on Cerro San Felipe and Cerro Machin in central Oaxaca, Mexico (fig. 191).'J See Appendix 1 for the locality records of the 19 specimens examined. Hyla thorectes Adler Hyla thorectes Adler, 1965, p. 10 [holotype, U.M.M.Z. No. 124390 from 37 kilometers north (by road) of San Gabriel Mixtepec, Oaxaca, Mexico, ele- vation 1860 meters; Kraig Adler collector]. Diagnosis: This moderately small species has a mottled brown and green dorsum, throat and chest boldly mottled with dark brown or black, fingers essentially lacking webs, and feet only about half webbed. The mottling on the venter immediately distinguishes Hyla thorectes from all other Middle American hylids. Description: Males of this moderately small species attain a maximum snout-vent 9 Dr. Robert G. Webb recently obtained two speci- mens of a frog that probably is this species. The specimens were collected on July 21, 1968, at 16 kilometers southwest of Cuquila, Oaxaca, elevation 2400 meters. This locality is just north of Chica- huaxtla on the road to Putla in the Sierra Madre del Sur. 98c 94° 18' / < 3 L' / • H. hazelae o H. thorectes V /■•V KILOMETERS -L_ 18" 98° 94° Fie. 191. Distribution of Hyla hazelae and Hyla thorectes. length of 34.2 mm., and females reach 37.3 mm. In a series of 20 males from the south slope of the Sierra Madre del Sur, 37 kilo- meters north of San Gabriel Mixtepec, Oaxa- ca, Mexico, the snout-vent length is 29.8 to 34.2 (mean, 31.9) mm.; the ratio of tibia length to snout- vent length is 0.485 to 0.511 (mean, 0.496); the ratio of foot length to snout- vent length is 0.438 to 0.482 (mean, 0.464); the ratio of head length to snout-vent length is 0.300 to 0.330 (mean, 0.310); the ratio of head width to snout-vent length is 0.316 to 0.357 (mean, 0.337), and the ratio of the diameter of the tympanum to that of the eye is 0.342 to 0.412 (mean, 0.385). One fe- male from the same locality has a snout-vent length of 37.3 mm. and differs from males in having a proportionately larger tympanum. The ratio of the diameter of the tympanum to that of the eye is 0.500. The head is as wide as, or slightly wider than, the body, and the top of the head is flat or barely convex. In dorsal profile, the snout is bluntly rounded with a minute point terminally; in lateral profile, the snout is trun- cate, barely rounded dorsally. The snout is short, and the noticeably protuberant nostrils are situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is moderately angular, and the loreal region is barely concave; the lips are 1970 DUELLMAN: HYLID FROGS 389 thick and barely flared. A moderately heavy dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct. The tympanum is separated from the eye by a distance equal to nearly twice the diameter of the tympanum. The arms are moderately long and slender; an axillary membrane is absent. A low, scal- loped dermal fold, composed of intercon- nected tubercles is present on the ventrolat- eral surface of the forearm; a distinct dermal fold is present on the wrist. The fingers are moderately long and slender and bear large discs; the width of the disc on the third finger is nearly twice the diameter of the tym- panum. The subarticular tubercles are mod- erately large and subcorneal; none is definitely bifid. The supernumerary tubercles are small and conical. A large, flat, partially bifid pal- mar tubercle is present. The prepollex is moderately enlarged and bears nuptial ex- crescences in breeding males. The fingers are barely webbed (fig. 190B). The legs are moderately short and slender; the heels of the adpressed limbs overlap by about one- third of the length of the shank. The tibio- tarsal articulation extends to the posterior corner of the eye. A distinct transverse der- mal fold is present on the heel, and a low tarsal fold is present on the posterior two- thirds of the tarsus. The inner metatarsal tubercle is small, elliptical, and visible from above. A minute outer metatarsal tubercle is present. The toes are moderately long and slender and bear discs that are noticeably smaller than those on the fingers. The sub- articular tubercles are moderately small and subconical; the supernumerary tubercles are minute and indistinct. The toes are about one-half webbed (fig. 190D). The webbing extends from the base of the penultimate phalanx of the first toe to the distal end of the antepenultimate phalanx of the second, from the middle of the penultimate phalanx of the second to the middle of the antepenulti- mate phalanx of the third, from the middle of the penultimate phalanx of the third to the base of the antepenultimate phalanx of the fourth, and on to the middle of the penulti- mate phalanx of the fifth toe. The anal opening is directed posteroven- trally at the midlevel of the thighs. A mod- erately long anal sheath is present, and nu- merous small tubercles are present below the anal opening. The skin on the throat, belly, and posteroventral surfaces of the thighs is granular, whereas that on the other surfaces is smooth. The tongue is elongately ovoid, emarginate or shallowly notched posteriorly, and barely free behind. The dentigerous pro- cesses of the prevomers are widely separated, transverse or posteromedially inclined eleva- tions between the small, round choanae. Males have three to six teeth on each process, whereas females have five to eight teeth on each process. The vocal slits extend from the midlateral base of the tongue to the an- gles of the jaws. The vocal sac is single, me- dian, subgular, and moderately distensible. The general coloration of Hijla tliorectes is mottled dark brown and green above and white with brown or black mottling below (pi. 57, fig. 2). The dorsum is usually red- dish tan with dark brown flecks and metallic green flecks. The same color is present on the dorsal surfaces of the forelimbs, shanks, and feet. The dorsal surfaces of the thighs are brown with creamy tan mottling. The anterior and posterior surfaces of the thighs are dull tan. The upper flanks and axilla are pale yellow, whereas the lower flanks are white. The flanks are mottled with black. The throat and belly are white with dark gray or dark brown mottling or spots. The ventral surfaces of the limbs are dull yellow. The anal spots are creamy white, and the webbing on the feet is dull brown. The iris is dull bronze and heavily reticulated with black. One individual was pale yellowish tan above with many small dark brown flecks and a few metallic green spots. By day, the dor- sum becomes a darker brown, reddish brown in some individuals. The mottling on the ventral surfaces is black by day. In preservative, the dorsum is dull brown with faint bluish gray flecks or spots. The flanks are creamy white with brown or black mottling, and the anterior and posterior sur- faces of the thighs are dull brown. Distinct transverse anal stripe and spots are present. The \ enter is creamy tan with dark brown or 390 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 192. Tadpole of Hyla thorectes, K.U. No. 104169. x 3. black spots and mottling on the throat and anterior part of the belly. Tadpoles: A typical tadpole in develop- mental stage 27 has a body length of 11.4 mm. and a total length of 34.8 mm. The body is elongately ovoid and not depressed. In dor- sal profile, the snout is bluntly rounded, and in lateral profile, it is round. The eyes are moderately small, widely separated, and di- rected dorsoslaterally. The nostrils are di- rected anterolaterally at a point about mid- way between the eyes and the tip of the snout. The opening of the sinistral spiracle is on the midline at a point about midway of the length of the body. The anal tube is long and dextral. The caudal musculature is ro- bust and extends nearly to the tip of the long, terminally rounded tail. At midlength of the tail, the depth of the caudal musculature is equal to the combined depths of the dorsal and ventral fins. The dorsal fin does not ex- tend onto the body (fig. 192). The body is dark brown with bluish white Hecks on the flanks and silvery flecks on the belly. The caudal musculature is tan with brown flecks and the iris is pale gold. In pre- servative, the body is dull brown, and the cau- dal musculature is creamy tan with dull brown flecks. A few flecks are present on the transparent fins. The mouth is ventral and small; its width is equal to somewhat less than half of the greatest width of the body. The mouth is completely bordered by a single row of small, blunt papillae. The lips are indented later- ally; in this lateral fold, additional papillae are present. The beaks are moderately ro- bust and bear large pointed serrations. The upper beak forms a broad arch with long slender lateral processes; the lower beak is broadly V-shaped. There are two upper and three lower rows of teeth. The upper rows are nearly equal in length; the second upper row is narrowly interrupted medially. The lower rows are complete; the first and second lower rows are nearly as long as the upper ones, but the third lower row is noticeably shorter (fig. 193). Hatchlings are in developmental stage 25, except that the spiracle is not apparent. The hatchling tadpoles lack gills and have no yolk- bulge, but a faint amount of yolk is present in the gut. The eye is well developed. These small tadpoles are good swimmers and have two upper and three lower rows of teeth upon hatching. All of the teeth are slightly irregular, and the third lower row is poorly developed. The upper beak is keratinized but not the lower one. Fringing papillae are pres- ent in the same state as in tadpoles of much greater age. Two hatchlings have body lengths of 4.0 and 4.1 mm. and total lengths of 14.2 and 14.9 mm. Five tadpoles that were preserved at an age of 21 days are still in de- velopmental stage 25; these individuals have a well-developed spiracle and completely de- veloped caudal pigmentation. In these speci- mens, the body length varies from 5.0 to 5.5 mm., and the total length varies from 15.0 to 16.8 mm. Mating Call: The call consists of a series of moderately low-pitched notes. Call groups are composed of six to 24 notes, and the inter- val between call groups varies from 1.5 to more than five minutes. The note repetition ^m&%^^m Fig. 193. Mouth of tadpole of Ht/la thorectes, K.U. No. 104169. X 20. 1970 DUELLMAN: HYLID FROGS 391 rate is approximately 24 notes per minute. The notes have a duration of 0.17 to 0.25 (mean, 0.21) of a second and a pulse rate of 60 to 70 (mean, 67) pulses per second. The fundamental frequency varies from 122 to 134 ( mean, 126 ) cycles per second, and the domi- nant frequency varies from 2010 to 210S (mean, 2062) cycles per second (pi. 16, fig. 1). Males usually call in pairs; one individual answers the other almost immediately. Natural History: Adler (1965, p. 13) noted that he found this species calling from low vegetation along a stream on June 23. In August, 1966, I obtained males calling from herbs, bushes, ferns, and low trees over streams at night. Some males and females were sitting on trees near, but not over the stream. Tadpoles in later developmental stages were obtained from streams in February. The tadpoles cling to rocks in quiet pools; when they are disturbed they seek refuge in the mud or leaf litter at the bottom of the pool. Hyla thorectes is unique among members of the genus in northern Middle America by depositing its eggs on vegetation above the stream. Three clutches of 10 eggs each were found on the tips of leaves or the tips of the fronds of ferns. The large eggs have a diam- eter of about 5.1 mm.; the diameter of the developing embryo is about 4.2 mm. One recently metamorphosed young hav- ing a snout-vent length of 18.2 mm. was found on a bush at the edge of a stream in August. The dorsum was bronze-tan with metallic green flecks. The anterior and pos- terior surfaces of the thighs and the hands and feet were yellow. Remarks: Although Hyla thorectes differs significantly from hazelae in coloration, the two are somewhat alike in their external structural features and in the nature of the sphenethmoid and the nasal. Consequently, they are placed together in one group. Etymology: The specific name is Greek, meaning a warrior armed with a breast-plate and refers to the boldly marked chest and throat. Distribution: Hyla thorectes is known only from elevations between 1600 and 1900 meters on the Pacific slopes of the Sierra Madre del Sur in Oaxaca, Mexico (fig. 191). See Appendix 1 for the locality records of the 30 specimens examined. The Hyla enjthromma Group Definition: Frogs in this group belong to a moderately small, stream-breeding spe- cies; males attain a maximum snout-vent length of 36.3 mm., and females, 57.6 mm. The dorsum is pale green with no markings other than small dark brown or black flecks; there are no transverse bands on the limbs, and the posterior surfaces of the thighs are dull yellowish tan, but white stripes are pres- ent on the outer edges of the forearms and feet. The palpebral membrane is reticulated, and the iris is red. The fingers are about one- fourth webbed, and the toes are two-thirds webbed. Dermal fringes and appendages are absent from the limbs. A tarsal fold and an abbreviated axillary membrane are present. Males have a single, median, subgular vocal sac and horny nuptial excrescences on the pol- liees. The cranial elements are moderately well ossified; a large frontoparietal fontanelle is present. The sphenethmoid is short and does not extend anteriorly between the na- sals, which are broadly separated medially and not in contact with the sphenethmoid (fig. 194). The quadratojugal is present. The squamosal is in bony contact with the crista parotica, and the anterior arm of the squa- mosal extends about half the distance to the Fig. 194. Dorsal view of the skull of Hyla enj- thromma, K.U. No. 87782. x 6. 392 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 maxillary. The medial ramus of the ptery- goid is not in bony contact with the prootic. Prevomerine teeth are present. The tadpoles have moderately long tails and medium-sized ventral mouths with four upper and six lower rows of teeth. The mating call consists of a single, long, moderately low-pitched, slowly pulsed note. The haploid number of chromo- somes is 12. Composition: One species (Hyla ery- thromma) is included in the group, which in- habits moderate elevations in southern Mex- ico. Seventy-eight preserved frogs, two skele- tons, seven lots of tadpoles, and one preserved clutch of eggs have been examined. Comments: Superficially, Hyla erythrom- ma resembles Hyla miotympanum in struc- ture, coloration, and in the great sexual di- morphism in size. However, erythromma has a quadratojugal and tadpoles with four upper and six lower rows of teeth, whereas mio- tympanum lacks a quadratojugal and has tad- poles with two upper and three lower rows of teeth. On the basis of these differences, ery- thromma is placed in a group apart from miotympanum. It is most likely that the two groups evolved from a common ancestral stock that had a quadratojugal and tadpoles with two upper and three lower rows of teeth. The members of the Hyla miotympanum phy- letic line (arhorescandens and miotympan- um) lost the quadratojugal and retained a generalized tadpole, whereas erythromma re- tained the quadratojugal and developed spe- cialized tadpoles. Hyla erythromma Taylor Hyla erythromma Taylor, 1937, p. 48 [holotype, F.M.N.H. No. 100083 (formerly E.H.T.-H.M.S. No. 5976) from Agua del Obispo, Guerrero, Mexico; Ed- ward H. Taylor collector |. Smith and Taylor, 1948, p. 89. Diagnosis: This moderately small green frog is immediately distinguished from all other Mexican Hyla by having a red iris and a faintly reticulated palpebral membrane. In preservative, it is very similar to Hyla mio- tympanum, which differs by having more webbing between the fingers and a less dis- tinctive white stripe on the outer edge of the foot. Hyla erythromma has an abbreviated axillary membrane and white flecks postero- lateral to the anal opening; both of these are absent in miotympanum. Other red-eyed Middle American hylids include several spe- cies of Agalychnis, which have vertical pupils, and members of the Hyla uranochroci group; the latter have short, truncate snouts, and Hyla uranochroa, the green species in the group, has a large white spot below the eye. Description: Males of this moderately small species attain a maximum snout-vent length of 36.3 mm. and females reach 57.6 mm. In a series of 25 males from 8 kilometers south of Yetla, Oaxaca, Mexico, the snout-vent length is 30.5 to 36.3 (mean, 33.2) mm.; the ratio of tibia length to snout-vent length is 0.517 to 0.579 (mean, 0,546); the ratio of foot length to snout-vent length is 0.378 to 0.458 (mean, 0.416); the ratio of head length to snout-vent length is 0.335 to 0.361 (mean, 0.347 ) ; the ratio of head width to snout-vent length is 0.329 to 0.354 (mean, 0.341), and the ratio of the diameter of the tympanum to that of the eye is 0.476 to 0.560 (mean, 0.520). Four females from the same locality have snout- vent lengths of 45.0 to 57.6 (mean, 50.6) mm. and do not differ significantly from the males in any proportions. The head is as wide as the body, and the top of the head is flat; the eyes are large and protuberant. In dorsal profile the snout is acutely rounded, and in lateral profile it is bluntly rounded. The snout is moderately long; the nostrils are noticeably protuberant with a depressed internarial region and are situated at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is angular and distinctly curved; the loreal region is barely concave, and the lips are moderately thick and barely flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, and downward to the point of insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance equal to the diam- eter of the tympanum. The arms are moderately long and slender; a short axillary membrane extends about one- fourth of the length of the upper arm. A row of distinct tubercles is present on the ventrolateral edge of the forearm, and a weak transverse dermal fold is present on the wrist. 1970 DUELLMAN: HYLID FROGS 393 The fingers are moderately long and robust and bear large discs; the width of the disc on the third finger is equal to the diameter of the eye. The subarticular tubercles are mod- erately large and subcorneal; the distal tu- bercle on the fourth finger is distinctly bifid in most specimens. The supernumerary tu- bercles are small and subcorneal. A low, flat, bifid palmar tubercle is present. The prepol- lex is moderately enlarged and in breeding males, bears a horny nuptial excrescence. The fingers are about one-fourth webbed (fig. 195A). The webbing is vestigial between the first and second fingers, but connects the sec- ond finger from the base of the penultimate phalanx to the base of the antepenultimate phalanx of the third, and from the middle of the antepenultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are mod- erately long and slender; the heels of the ad- pressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal ar- ticulation extends to the snout. A transverse dermal fold and a conical tubercle are present on the heel. A thin, tarsal fold extends the full length of the tarsus; in some individuals this fold is barely discernible. The inner meta- tarsal tubercle is elongate, flat, and barely visible from above. A distinct, conical, outer metatarsal tubercle is present. The toes are moderately long and slender and bear discs that are only slightly smaller than those on the fingers. The subarticular tubercles are moderately small and subcorneal, and the su- pernumerary tubercles are distinct and sub- conical. The toes are about two-thirds webbed (fig. 195B). The webbing extends from the distal end of the penultimate pha- lanx of the first toe to the distal end of the penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the distal end of the antepenulti- mate phalanx of the third, from the base of the disc of the third to the middle of the antepenultimate phalanx of the fourth, and from the distal end of the antepenultimate phalanx of the fourth to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the upper level of the thighs. A broad anal sheath is present and numerous tubercles Fig. 195. Hand (A) and foot (B) of Hyhi ery- thromma, K.U. No. 87089. x 5. are present below and lateral to the anal opening. The skin on the throat, belly, and proximal posteroventral surfaces of the thighs is granular; elsewhere, the skin is smooth. The tongue is cordiform or elongately ovoid and not free behind. The dentigerous pro- cesses of the prevomers are small, widely separated, transverse or posteromedially in- 394 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 clined ridges between the moderately large, ovoid ehoanae. Males have four to seven (mean, 5.1) and females have seven to nine (mean, 8.1) teeth on each proeess. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moder- ately distensible. The general coloration of Hyla erythrom- ma is green above and white below with a distinctive red iris (pi. 56, fig. 5). When ac- tive at night, the dorsum is dark green with pale green flecks in some individuals. Creamy white stripes are present on the edge of the upper lip, the length of the flanks, and on the outer edges of the forearm and tarsus. The anal tubercles and anal stripe are white. The anterior surfaces of the thighs are orange- tan, and the posterior surfaces are orange- brown. The chin and chest are white, and the belly is pale creamy yellow. The under- surfaces of the legs are yellowish tan, and the ventral surfaces of the feet are brown. The webbing is tan. The iris is bright red and the palpebral membrane is faintly reticu- lated with greenish gold. In preservative the dorsum is pale grayish tan or bluish gray with or without darker flecks. The anterior and posterior surfaces of the thighs are yellowish brown, and the ven- ter is creamy white. In males, the venter is usually unmarked, whereas in females, blown flecks are present on the chest and on the edge of the chin. The flanks are brown with heavy white flecking. The edge of the upper lip, the outer edges of the forearms and feet, and the anal stripe are white. In specimens that have been preserved from three to five years, the iris is pale reddish bronze or pale yellow. Tadpoles: One tadpole in developmental stage 25 has a body length of 9.5 mm. Three tadpoles in developmental stage 38 have body lengths of 12.5 to 13.0 (mean, 12.8) mm. and total lengths of 37.5 to 40.0 (mean, 38.5) mm. Eight tadpoles in developmental stage 41 have body lengths of 13.0 to 14.0 (mean, 13.6) mm. and total lengths of 37.5 to 41.5 (mean. 40.1) mm. Two tadpoles in developmental stage 43 each have a body length of 14.5 mm. A typical tadpole in developmental stage 38 has a body length of 13.0 mm. and a total length of 40.0 mm. The body is rather robust and nearly as deep as wide. In dorsal profile, the snout is bluntly rounded and in lateral profile is is acutely rounded. The eyes are moderately small, widely separated, and di- rected dorsolaterally. The nostrils are direct- ed anterolaterally at a point about two-fifths of the distance from the eyes to the tip of the snout. The opening of the sinistral spira- cle is directed posteriorly at a point below the midline and about three-fifths of the dis- tance from the snout to the posterior edge of the body. The anal tube is short and dex- tral. The caudal musculature is robust and tapers gradually to a point just short of the terminally acute caudal fin. At midlength of the tail, the depth of the caudal musculature is noticeably greater than that of either the dorsal or ventral fin. The dorsal fin does not extend onto the body (fig. 196). The body and the dorsal part of the caudal musculature anteriorly is pale brown. The lateral surfaces of the caudal musculature are heavily flecked with dark brown, and dark brown flecks are present on the otherwise transparent caudal fin. The iris is red. In pre- servative, the body is dull brown; this color extends posteriorly on the dorsal surfaces of the tail, which is distinctly demarked laterally by dark brown. The ventral fin has a few dark brown flecks posteriorly, whereas flecks and small blotches are present throughout the length of the dorsal fin. The mouth is moderately large and ven- tral; the lips are broadly indented laterally. There are at least two rows of small papillae Fig. 196. Tadpole of Hyla enjthromma, K.U. No. 87630. X 3. 1970 DUELLMAN: HYLID FROGS 395 rnROtPi Fig. 197. Mouth of tadpole of Hyla erythromma, K.U. No. 87630. x 17. completely bordering the mouth; three or more rows are present on parts of the lower lip in some specimens, and additional small papillae are present in the lateral fold. The beaks are slender and bear blunt serrations. The upper beak is in the form of a broad arch with slender, terminally expanded lat- eral processes. The lower beak is shallowly V-Shaped. There are four upper and six low- er rows of teeth. The upper rows are about equal in length and extend to the edges of the lips; the fourth upper row is narrowly interrupted medially. The lower rows are complete; the first four or five lower rows are nearly as long as the upper rows, but the fifth and sixth usually are noticeably shorter (fig. 197). Mating Call: The call of Hyla erythrom- ma consists of a long, moderately low-pitched, slowly pulsed note. Each call group consists of a single note, and call groups are repeated at intervals of about 30 to 50 seconds. In one analyzable recording (pi. 15, fig. 3) the note has a duration of 0.62 of a second, 26 pulses per second, a fundamental frequency of 87 cycles per second, and a dominant frequency of 2266 cycles per second. Natural History: Hyla erythromma in- habits the lower reaches of montane cloud forests and low pine-oak forests. In streams in northern Oaxaca, numerous individuals have been found at night on vegetation along the streams in the rainy season; noticeably fewer individuals have been observed along the same streams in the dry season, although males have been heard to call at both times of the year. Tadpoles have been found in the streams in June, July, and February. The tadpoles inhabit quiet pools in the streams and seek shelter amidst debris in the bottom of the stream. Metamorphosing young have been found in Oaxaea and in Guerrero in June. The young have the bright red iris of the adults and are distinctly marked with white elbows and heels and a white labial stripe, all of which contrast with the dull olive-green dor- sum. Remarks: I have not seen living or re- cently preserved adults from Guerrero. Some minor differences exist between the old pre- served specimens from Guerrero and the fresh material from Oaxaca. The specimens from Guerrero tend to be more slender and have narrower digits on the finger. The differences in these highly subjective characters most likely are due to differential perservation. I am unable to find differences in the tadpoles from Guerrero from those from Oaxaca, and recently metamorphosed young from the two regions are identical. Etymology: The specific name is derived from the Greek erythros meaning red, and from the Greek omma meaning eye; the name refers to the diagnostic red eye of this species. Distribution: Hyla erythromma is known from the Pacific slopes of the Sierra Madre del Sur at elevations of 700 to 950 meters in Guerrero, Mexico, and from elevations of 600 to 850 meters on the northern slopes of the Sierra de Juarez in northern Oaxaca, Mexico (fig. 198). See Appendix 1 for the locality records of the 88 specimens examined. The Hyla pinorum Group Definition: The members of this group are small stream-breeding species; males at- tain a maximum snout- vent length of 33.1 mm. and females, 34.6 mm. The dorsum is yellow or pale tan with dark flecks, spots, or middorsal line. The thighs are uniform yel- low or tan, and the shanks and forearms are marked by flecks or narrow transverse bars. The palpebral membrane is clear. The fin- gers are no more than one-half webbed, and the toes are about three-fourths webbed (fig. 199). Dermal fringes and appendages are lacking on the limbs. A distinct tarsal fold 396 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 0 50 100 200 KILOMETERS 102° 98° 94° Fig. 198. Distribution of Hyla erythromma. and an axillary membrane are present. The tympanum is evident (melanomma) or con- cealed ( pinorum ) . Males have single, me- dian, subgular vocal sacs and have ( melanom- ma) or lack {pinorum) horny nuptial tuberosi- ties on the pollices. The cranial elements are moderately well ossified; a large fronto- parietal fontanelle is present. The sphen- ethmoid is large and extends anteriorly be- tween the nasals (pinorum) or not (mela- nomma). The nasals broadly overlap the sphenethmoid in pinorum and lie adjacent to it in melanomma (fig. 200). The quadrato- jugal is present, reduced to a small sliver, or absent. The squamosal is in bony contact with the crista parotica in pinorum and nar- rowly separated in melanomma; the anterior arm of the squamosal extends no more than one-third of the distance to the maxillary. The medial ramus of the pterygoid is not in bony contact with the prootic. Prevomerine teeth are present. The tadpoles have long, terminally rounded tails and moderately large mouths with deep lateral folds and two upper and five lower rows of teeth. The mating call consists of a series of short notes. The number of chromosomes is unknown. Composition: Two species (H. mela- nomma and pinorum), the former composed of two subspecies, are included in the group, which is restricted to the Atlantic slopes of the Chiapan highlands and the Pacific slopes of the Sierra Madre del Sur in Mexico. Of the three taxa, 103 preserved frogs, four skele- tons, and five lots of tadpoles have been ex- amined. Comments: Hyla pinorum and melanom- ma are placed together mostly on the basis of the similarities of their tadpoles, which are distinctive in having two upper and five low- er rows of teeth (figs. 101 and 102). Other- wise, the species are sufficiently different that they might be placed in separate groups, al- though neither fits closely with any of the other groups of Mexican stream-breeding hy- lids. In some respects, the Hyla pinorum group might be closely related to the more advanced Hyla mixomaculata group, in which the adults lack a tympanum and vocal sac, and the tadpoles have seven upper and 11 lower rows of teeth. Externally, Hyla pinor- um resembles members of the Hyla mixo- maculata group by having barred limbs and by lacking a tympanum and nuptial excres- cences. However, it differs from members of that group by having a quadratojugal, the squamosal in bony contact with the crista parotica, much smaller nasals, an anteriorly notched sphenethmoid, and a vocal sac. Hyla melanomma differs from the species in the 1970 DUELLMAN: HYLID FROGS 397 Fig. 199. Hands and feet of members of the Hyla pinorum group. A and C. Hyla tnelanomma melanomma, K.U. No. 86949. B and D. Hyla pinorum, U.M.M.Z. No. 125369. x 5. Hyla mixomaculata group by having a tym- panum, nuptial excrescences in breeding males, and no transverse bars on the limbs. The cranium of H. melanomma resembles those of members of the Hyla mixomaculata group, except that in the former the nasals are rather narrowly separated and lie anterior to the sphenethmoid. Hyla pinorum possibly evolved on the Pa- cific slopes of the Sierra Madre del Sur at a time when melanomma was isolated on the Atlantic slopes of the Chiapan highlands. Sub- sequently, melanomma probably migrated in- to the Sierra Madre del Sur, leaving behind a population in Chiapas that differentiated slightly, thereby giving rise to the subspecies bivocata in Chiapas and melanomma in the Sierra Madre del Sur. Hyla melanomma Taylor Hyla melanomma Taylor, 1940d, p. 508. Diagnosis: This small species has uni- formly yellow thighs and a distinct axillary membrane. The only other Middle American hylid having these characters is Hyla ebrac- cata, which has a more extensive axillary web and usually a dark hourglass-shaped mark on the dorsum. The dorsal markings in mela- nomma consist of small dark flecks. Hyla melanomma is most easily confused with Hyla sumichrasti, which has similar coloration and 398 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 200. Dorsal views of skulls. A. Hyla mela- nomma, K.U. No. 86953. B. Hi/la pinorum, U.M.M.Z. No. 125367. x 6. an abbreviated axillary membrane, but differs from melanomma by having a shorter anal sheath and usually no more than two teeth on each prevomerine process ( melanomma usu- ally has four or five teeth). Considerable dif- ferences obtain in the skulls and tadpoles ( see respective descriptions). See the diagnoses and descriptions of the subspecies for further characteristics ' and comparisons. Content: Two subspecies are recognized: Hyla to. melanomma Taylor inhabits the Pa- cific slopes of the Sierra Madre del Sur in Mexico and H. m. bivocata Duellman and Hoyt occurs on the Atlantic slopes of the Chiapan highlands in Mexico. Although minor differences exist in the amount of webbing, size, and in certain para- meters of the mating calls, the size of the tympanum relative to that of the eye and the amount and distribution of dark pigment on the dorsum are the major differences be- tween the subspecies. The Chiapan subspe- cies (H. m. bivocata) has a small tympanum ( less than 43 per cent of the eye ) and few large dark flecks on the body, whereas the nominate subspecies in the Sierra Madre del Sur has a larger tympanum (50 per cent or more of the eye) and many small dark flecks on the body and shanks. Distribution: Hyla melanomma occurs at elevations of 900 to 2000 meters on the Pacific slopes of the Sierra Madre del Sur in Guerrero and Oaxaca and on the Atlantic slopes of the Chiapan highlands, Mexico (fig. 203). Hyla melanomma melanomma Taylor Hyla melanomma Tavlor, 1940d, p. 508 [holotvpe, F.M.N.H. No. 100074 (formerly E.H.T.-H.M.S. No. 21578) from 11 kilometers east of Chilpancingo, Guerrero, Mexico; Edward H. Taylor collector]. Smith and Taylor, 1948, p. 89. Hyla bivocata oaxacae Lynch, in Smith, Langebar- tel, and Williams, 1964, p. 23 [nomen nudum]. Hyla melanomma melanomma: Duellman, 1966b, p. 272. Diagnosis: This subspecies can be dis- tinguished from other species of Middle American hylids by means of the characters given in the diagnosis of the species and from the subspecies bivocata by having a larger tympanum ( tympanum/eye ratio in mela- nomma is more than 0.500 and in bivocata, less than 0.430) and more numerous and smaller dark flecks on the dorsum. Description: Males of this subspecies at- tain a maximum snout-vent length of 29.9 mm., and females reach 31.5 mm. In a series of 19 males from streams at 910 and 1040 meters above (north of) San Gabriel Mix- tepee, Oaxaca, Mexico, the snout- vent length is 26.7 to 28.3 (mean, 27.4) mm.; the ratio of tibia length to snout-vent length is 0.482 to 0.527 (mean, 0.505); the ratio of foot length to snout-vent length is 0.410 to 0.446 (mean, 0.430); the ratio of head length to snout-vent length is 0.300 to 0.337 (mean, 0.327); the ratio of head width to snout-vent length is 0.318 to 0.345 (mean, 0.330), and the ratio of the diameter of the tympanum 1970 DUELLMAN: HYLID FROGS 399 to that of the eye is 0.500 to 0.667 (mean, 0.590). In seven males from the vicinity of Agua del Obispo, Guerrero, Mexico, the snout-vent length is 25.1 to 29.9 (mean, 27.1) mm.; in three females from the same locality, the snout-vent length is 29.2 to 31.5 (mean, 30.1) mm. In the males from Agua del Obis- po, the ratio of the diameter of the tympanum to that of the eye is 0.500 to 0.516 (mean, 0.509). The head is as wide as the body, and the top of the head is slightly convex. In dorsal profile, the snout is acuminate; in lateral pro file, it is bluntly rounded. The snout is long, and the slightly protuberant nostrils are situ- ated at a point about four-fifths of the dis- tance from the eyes to the tip of the snout. The canthus is rounded and barely evident; the loreal region is barely concave, and the lips are moderately thick and not flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum; a vertical fold of skin obscures the posterior rim of the tympanum, which otherwise is distinct and separated from the eye by a distance equal to about two-thirds of the diameter of the tympanum. The arms are moderately long and slender; an axillary membrane extends to the middle of the upper arm. A weak, tubercular fold is present on the ventrolateral edge of the fore- arm, and a weak transverse dermal fold is present on the wrist. The fingers are short and bear moderately large discs; the width of the disc on the third finger is equal to the diameter of the eye. The subarticular tuber- cles are moderately large and subcorneal; the distal tubercle on the fourth finger is barely bifid in most individuals. The supernumerary tubercles are small, subcorneal, and irregu- larly arranged on the basal segments of each digit. A tripartite palmar tubercle is present. The prepollex is moderately enlarged and in breeding males bears a horny nuptial excres- cence. The fingers are about one-half webbed (fig. 199A). The webbing is vestigial be- tween the first and second fingers, but ex- tends from the middle of the penultimate phalanx of the second to the distal end of the antepenultimate phalanx of the third and on to the distal end of the antepenultimate phalanx of the fourth finger. The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one- third of the length of the shank. The tibio- tarsal articulation extends to the eye. A few small tubercles are present on the heel, and a distinct tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is low, flat, elliptical, and broader basally than distally. The toes are moderately long and slender and bear discs that are slightly smaller than those on the finger. The sub- articular tubercles are moderately large and subcorneal. The supernumerary tubercles are moderately large, subcorneal, and present in a single row on the proximal segment of each digit. The toes are about three-fourths webbed (fig. 199C). The webbing extends from the middle of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the base of the penultimate phalanx of the third, from the distal end of the penultimate pha- lanx of the third to the base of the penulti- mate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally near the upper level of the thighs. A short, heavy anal sheath is present. Numer- ous large tubercles are present below the anal opening. The skin on the dorsal surfaces of the body and limbs, and on the ventral sur- faces of the arms and shanks is smooth; that on the throat, belly, and ventral surfaces of the thighs is heavily granular. The tongue is broadly eordiform, barely notched pos- teriorly, and only slightly free behind. The dentigerous processes of the prevomers are widely separated, posteromedially inclined elevations between the moderately small, ovoid choanae. There are three to five teeth on each elevation. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla melanom- ma melanomma consists of a pale brown or yellowish tan dorsum with scattered small olive-brown or dark brown flecks (pi. 58, fig. 400 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 ** $. -V -,-.V : i Fig. 201. Tadpoles of members of the Hyla pinorum group. A. Hyla mela- nomma melanotnma, K.U. No. 87608. B. Hyla pinorum, K.U. No. 87611. X 3. 1 ) . At night, the dorsum is pale yellowish tan with little indication of dorsal markings. Ry day, the dorsal ground color darkens to a darker tan or pale brown, and the dark flecks are evident on the body and dorsal surfaces of the limbs. A dark brown canthal stripe is evident in most individuals, which usually also have a dark brown line along the supra- tympanic fold, and a series of interconnected brown spots along the flank. Ventral to this series of spots, the flank is creamy white. The anterior and posterior surfaces of the thighs are dull yellow, and the belly is creamy white. A faint white anal stripe is present in most individuals. The iris varies from a pale bronze to a deep bronze lightly flecked with black. In preservative, the dorsum is pale grayish tan or pale brown with dark brown or black flecks on the forearm, body, and shanks. The flanks, thighs, and ventral surfaces are creamy tan. Tadpoles: Five tadpoles in developmen- tal stage 25 have body lengths of 7.1 to 7.4 (mean, 7.2) mm. and total lengths of 16.7 to 17.3 (mean, 16.9) mm. The largest tad- pole, in developmental stage 38, has a body length of 13.8 mm. and a total length of 36.9 mm. A typical tadpole in developmental stage 36 has a body length of 12.6 mm. and a total length of 36.2 mm. The body is streamlined, noticeably tapered posteriorly. The body is slightly wider than deep. In dorsal profile, the snout is bluntly rounded, and in lateral profile, it is round. The eyes are large, widely separated, and directed dorsolaterally. The nostrils are directed anterolaterally at a point about two-fifths of the distance from the eyes to the tip of the snout. The opening of the sinistral spiracle is directed posterodorsally at a point well below the midline and about two-thirds of the distance from the snout to the posterior end of the body. The anal tube is short and dextral. The caudal musculature is moderately heavy and extends nearly to the tip of the acutely rounded tail. The fins are moderately shallow; at midlength of the tail, the depth of either fin is approximately equal to the depth of the caudal musculature. The dorsal fin does not extend onto the body (fig. 201A). In preservative, the body is dull grayish brown; ventrally, small white flecks are evi- dent. The tail is creamy tan with minute dark flecks on the musculature and fins. The mouth is ventral and medium in size; the width of the mouth is equal to about one- half of the greatest width of the body. Deep lateral folds are present in the lips, which are completely bordered by a single row of long, slender papillae. Additional papillae are present in the lateral folds. The beaks are moderately robust and bear long blunt serra- tions. The upper beak is in the form of a broad arch with slender lateral processes; the lower beak is broadly V-shaped. There are two upper and five lower rows of teeth. The upper rows are long; the second upper row is narrowly interrupted medially. The first four lower rows are as long as the upper ones and complete; the fifth lower row is somewhat shorter than the others (fig. 202A). 1970 DUELLMAN: HYLID FROGS 401 ,0^mm r^fflffiMfypffy1*^ Fig. 202. Mouths of tadpoles of members of the Hyla pinorum group. A. Hyla melanomma melanom- ma, K.U. No. 87608. B. Hyla pinorum, K.U. No. 87611. x 15. Mating Call: The mating call of Hyla melanomma melanomma consists of a series of quickly repeated short notes interspersed by individually produced long notes. The repetition rate of the short notes varies from 71 to 90 (mean, 78) notes per minute. The duration of each note is 0.07 to 0.08 of a second, and the interval between notes varies from 0.45 to 0.50 of a second. There are approximately 300 pulses per second in these notes which have a fundamental frequency of 163 to 217 (mean, 190) cycles per second and dominant frequency of 2286 to 2387 (mean, 2336) cycles per second (pi. 17, fig. 2). Recordings of the long note produced by one individual provides the following data: the duration of the note is 0.31 to 0.37 of a second. The pulse rate is about 220 pulses per second; the fundamental frequency is about 139 cycles per second, and the domi- nant frequency is about 2112 cycles per sec- ond. Most calling males produce a series of short notes; one or two long notes are inter- spersed in the series of short notes, or a series of short notes is followed by several long notes. One individual was observed to pro- duce solely long notes. Another individual produced 28 short notes in 20 seconds; these were followed immediately by three long notes. Natural History: Hyla melanomma melanomma inhabits cloud forest and pine- oak forest, where this species breeds in small streams. Calling males have been observed in low trees and bushes along, or overhanging, small streams. Calling males have been ob- served in the months of June, July, and Au- gust. Taylor (1940d, p. 510) noted that adults and juveniles were taken from bromeliads in low trees growing along a small stream at a locality 11 kilometers east of Chilpancingo, Guerrero, Mexico, on August 20, 1939. Tadpoles were obtained in shallow, gravel- bottomed pools in small rivulets at Agua del Obispo, Guerrero, Mexico, and north of San Gabriel Mixtepec, Oaxaca, Mexico, in June. At the latter locality on June 20, 1964, a metamor- phosing young was found on a bush over- hanging the stream. This individual has a snout-vent length of 15.3 mm. and a tail stub of 6.0 mm. in length. Taylor ( 1940d, p. 510) noted that the dor- sal coloration in life was "light olive-green, lighter on side and above limbs ..." I have not seen living individuals so colored. Duellman (1966b, p. 272) reported on the geographic variation in this subspecies and assigned two specimens from Campamento Vista Hermosa, Oaxaca, to H. melanomma melanomma. Further study of these speci- mens, plus additional material from the same locality revealed that the specimens from Campamento Vista Hermosa are not Hyla melanomma, but instead are representatives of Hyla dendroscarta. Etymology: The specific name is derived from the Greek melanos, meaning black, and the Greek, omma, meaning eye. Taylor (1940d, p. 510) used this name in reference to his observation that "the eyeball is very black and seen through the eyelid makes the eye- lids appear black. . . ." Distrihution : Hyla melanomma mela- nomma occurs at elevations of 900 to 2000 402 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 100° 96° 92° • 1 \ 1 -' L r \i ■? i i 'i ■*. . S i r'"i i i V '* > ■•« ■*■'"■> < /' Vs* i .-■rT •H.m o H.m melanomma bivocata \ x? 18° \ r <,■ s 7" j 9 > i f i 16° 0 50 150 • 8 ^^j / KILOMETERS i 1 " 18' - 16' 100° 96° 92° Fie. 203. Distribution of the subspecies of Hyla melanomma. meters on the Pacific slopes of the Sierra Madre del Sur from central Guerrero to south- central Oaxaca, Mexico (fig. 203). In addition to the 79 specimens examined that are listed in Appendix 1, Smith and Brandon ( 1968, p. 50 ) reported five speci- mens (U.I.M.N.H. Nos. 78826-30) from 27 kilometers south of Juchatengo, Oaxaca, Mex- ico. Hyla melanomma bivocata Duellman and Hoyt Hyla bivocata Duellman and Hoyt, 1961, p. 414 [holotype, K.U. No. 58446 from a small stream above (6.2 kilometers by road south of) Rayon Mescalapa, Chiapas, Mexico; William E. Duellman and Dale L. Hoyt collectors], Hyla melanomma bivocata: Duellman, 1966b, p. 272. Diagnosis: This subspecies can be dis- tinguished from other species of Middle American hylids by means of the characters given in the diagnosis of the species and from the nominate subspecies by having a smaller tympanum ( tympanum/eye ratio in bivocata is less than 0.430 and in melanomma, more than 0.500) and less flecking on the dorsum, especially on the shanks, than in melanomma. Description: Males of this subspecies at- tain a maximum snout-vent length of 28.5 mm.; the single known female has a snout- vent length of 26 mm. In a series of 10 males from streams above (south of) Rayon Mes- calapa, Chiapas, Mexico, the snout-vent length is 26.2 to 28.5 (mean, 27.1) mm.; the ratio of tibia length to snout-vent length is 0.508 to 0.547 (mean, 0.528); the ratio of foot length to snout-vent length is 0.426 to 0.447 (mean, 0.441); the ratio of head length to snout-vent length is 0.302 to 0.331 (mean, 0.319); the ratio of head width to snout-vent length is 0.323 to 0.347 (mean, 0.335), and the ratio of the diameter of the tympanum to that of the eye is 0.278 to 0.428 (mean, 0.359). In most structural characters, Hyla mela- nomma bivocata is like the nominate subspe- cies, and the reader is referred to the descrip- tion of that form for the details. Hyla mela- nomma bivocata differs from the nominate subspecies by having a smaller tympanum (see preceding paragraph) and by having slightly less webbing. The webbing between the first and second fingers is vestigial, and the webbing extends from the distal end of the antepenultimate phalanx of the second to the base of the antepenultimate phalanx of the third and on to the distal end of the ante- penultimate phalanx of the fourth finger. The toes are about two-thirds webbed. The web- bing extends from the middle of the penulti- mate phalanx of the first toe to the distal end of the antepenultimate phalanx of the second. 1970 DUELLMAN: HYLID FROGS 403 from the middle of the penultimate phalanx of the second to the middle of the antepenulti- mate phalanx of the third, from the middle of the penultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The number of teeth on each dentigerous process of the prevomer varies from two to four. The general coloration of Hyla melanom- ma bivocata consists of a yellowish tan or pale brown dorsum, usually marked with bold dark spots (pi. 58, fig. 2). At night, the dor- sum is pale yellow, and dorsal markings are barely evident. By day, the dorsal ground color darkens to pale tan or pale reddish brown, and dark olive-brown spots become evident. The loreal region is dark brown, and a dark brown stripe is present on the supra- tympanic fold. The flanks are pale yellow, and the belly is creamy yellow. The anterior and posterior surfaces of the thighs are dull yellow. A faint white anal stripe is present. The iris is pale golden bronze with fine black flecks. In preservative, the dorsal surfaces are pale tan and the venter is white. A black bar extends from the nostril to the eye and a faint anal stripe is present. Tadpoles: The tadpoles of this subspecies are unknown. Mating Call: The call of Hijla melanom- ma bivocata consists of a series of short notes and occasional long notes. The short notes are repeated at a rate of 60 to 65 notes per minute. The notes have a duration of 0.04 to 0.10 (mean, 0.07) of a second; the interval between notes varies from 0.58 to 0.70 ( mean, 0.64) of a second. The pulse rate is 220 to 260 (mean, 240) pulses per second; the fundamental frequency is 130 to 144 (mean, 137) cycles per second, and the dominant frequency is 2456 to 2470 ( mean, 2463 ) cycles per second. The recording of a long note shows that it has a duration of 0.53 of a second and a pulse rate of 280 pulses per second. The fundamental frequency is 152 cycles per second, and the dominant fre- quency is 756 cycles per second (pi. 17, fig. 3). Most males were observed to produce only series of short notes, but one individual was observed repeatedly to emit only the single long note. Two individuals were observed to produce a long note followed by a series of short notes. Natural History: Hyla melanomma bivocata occurs along streams in cloud forest in Chiapas. Most of the specimens have been collected along streams at night in the months of June, July, and August. Ronald G. Altig obtained seven specimens from elephant-ear plants (Xanthosoma) along a stream by day in June [Smith and Brandon (1968, p. 49)]. Remarks: Duellman and Hoyt (1961) described Hyla bivocata and did not compare it with Hyla melanomma. Duellman (1966b) noted the similarity between bivocata and melanomma and assigned the former as a subspecies of the latter. Smith and Brandon ( 1968, p. 50) suggested that bivocata was spe- cifically distinct from melanomma; the status of the two populations cannot be determined definitely with the use of only preserved speci- mens. Etymology: The specific name is derived from the Latin hi-, meaning two, and the Latin vocatus, meaning call, and refers to the two kinds of notes produced by these frogs. Distribution*: Hyla melanomma bivocata is known only from cloud forest at elevations between 1600 and 1700 meters on the north- ern slopes of the central highlands of Chiapas, Mexico (fig. 203). In addition to the locality records of the 15 specimens listed in Appendix 1, Smith and Brandon ( 1968, p. 49 ) listed seven specimens from 25 kilometers south of Ixhuatan and three from 32 kilometers north of Jitotol, Chiapas; both localities are near the type locality. Hyla pinorum Taylor Hijla pinorum Taylor, 1937, p. 46 [holotype, U.I.M.N.H. No. 25049 (formerly E.H.T.-H.M.S. No. 5972) from Agua del Obispo, Guerrero, Mexico; Edward H. Taylor collector]. Smith and Taylor, 1948, p. 87. Ftychohula leonhardschultzei (in part): Duell- man, 1960c, p. 191; 1963c, p. 323. Diagnosis: This small species has strongly barred limbs, except the thighs, and lacks a tympanum. The feet are about two-thirds webbed, and large tubercles are present be- low the anal opening. Hyla pinorum differs 404 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 from other tympanum-less Mexican Hyla by having large tubercles below the anus. The other tympanum-less species have bands on the dorsal surfaces of the thighs, except nubi- cola, which has fully webbed feet. Description: Males of this species attain a maximum snout-vent length of 33.1 mm., and females reach 34.6 mm. In five males from San Andreas de la Cruz, Guerrero, Mex- ico, the snout-vent length is 28.5 to 33.1 (mean, 30.3) mm.; the ratio of tibia length to snout- vent length is 0.495 to 0.520 (mean, 0.507); the ratio of foot length to snout- vent length is 0.395 to 0.423 (mean, 0.408); the ratio of head length to snout-vent length is 0.313 to 0.344 (mean, 0.325), and the ratio of head width to snout-vent length is 0.332 to 0.361 (mean, 0.347). The head is slightly wider than the body, and the top of the head is barely convex. In dorsal profile, the snout is bluntly rounded; in lateral profile, it is rounded. The snout is moderately long; the nostrils are noticeably protuberant and are situated at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is round- ed; the loreal region is concave, and the lips are moderately thick and slightly flared. A thin dermal fold extends posteriorly from the eye to a point above the insertion of the arm. The tympanum is not visible through the skin. The arms are moderately long and slender; an axillary membrane extends to the mid- length of the upper arm. A faint dermal fold is present along the ventrolateral edge of the forearm; no dermal fold is present on the wrist. The fingers are moderately long and slender and bear medium-sized discs; the width of the disc on the third finger is equal to about one-fourth of the diameter of the eye. The subarticular tubercles are moderate- ly large and subcorneal; the distal tubercle on the fourth finger is barely bifid. The super- numerary tubercles are moderately large, sub- conical, and irregularly arranged on the proxi- mal segments of each digit. A low, flat, bifid palmar tubercle is present. The prepollex is moderately enlarged and in breeding males does not bear a nuptial excrescence. The fin- gers are barely webbed (fig. 199B). The web- bing is vestigial between the first and second fingers and extends from the distal end of the antepenultimate phalanx of the second to the base of the antepenultimate phalanx of the third and on to the middle of the antepenulti- mate phalanx of the fourth finger. The hind limbs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A small tubercle is present on the heel, and a weak tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is small, round, and elevated. An outer metatarsal tubercle is absent. The toes are long and slender and bear small discs. The subarticular tubercles are small and coni- cal; the supernumerary tubercles are small and subconical. The toes are about two-thirds webbed (fig. 199D). The webbing extends from the middle of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the middle of the penultimate phalanx of the second to the mid- dle of the antepenultimate phalanx of the third, from the middle of the penultimate phalanx of the third to the middle of the antepenultimate phalanx of the fourth and on to the middle of the penultimate phalanx of the fifth toe. The anal opening is directed posteroven- trally at the midlevel of the thighs and is bordered on either side by two large tuber- cles. The skin on the dorsal surfaces and on the ventral surfaces of the arms and shanks is smooth; that on the throat, belly, and ven- tral surfaces of the thighs is granular. The tongue is ovoid, slightly longer than wide, and shallowly notched anteriorly and pos- teriorly, or not, and not free behind. The dentigerous processes of the prevomers are small, elliptical elevations between the mod- erately large ovoid choanae. There are three or four teeth on each elevation. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moder- ately distensible. The general coloration of Hyla pinorum is pale yellowish tan with pale brown, irregu- lar markings on the dorsum and brown trans- verse bars on the limbs (pi. 58, fig. 3). The dorsum varies from a pale yellowish tan to a 1970 DUELLMAN: HYLID FROGS 405 pale reddish tan, and the dorsal markings vary from a pale olive-brown to a reddish brown. Usually, the markings consist of irreg- ularly connected blotches and spots, but one individual (U.M.M.Z. No. 125367) lacks spots and blotches on the dorsum and has instead a dark middorsal line (pi. 58, fig. 4); this in- dividual has weakly defined bars on the limbs. In other specimens, narrow, transverse dark bars are present on the dorsal surfaces of all segments of the limbs. The anterior and pos- terior surfaces of the thighs and the flanks are creamy yellow, and the venter is creamy white. The anal tubercles are white, and the iris is pale bronze with a grayish brown suf- fusion. Recently metamorphosed young are col- ored noticeably different than the adults. The limbs are orange with brown bands, and the dorsum is marbled dark brown and yellowish tan. The posterior surfaces of the thighs are bright orange (pi. 58, fig. 7). In preservative, the adults are pale tan with dark brown markings dorsally. The an- terior and posterior surfaces of the thighs are creamy tan, and the flanks and venter are creamy white. Tadpoles: A large developmental series of tadpoles was obtained at San Andreas de la Cruz, Guerrero, Mexico, in June, 1964 ( table 39, fig. 204 ) . A typical tadpole in de- velopmental stage 37 has a body length of 14.5 mm. and a total length of 41.0 mm. The body is ovoid, barely wider than deep. In dorsal profile, the snout is bluntly rounded, and in lateral profile it is more acutely round- ed. The eyes are moderately large, widely separated, and directed dorsolaterally. The nostrils are directed anterolaterally at a point about midway between the eyes and the tip of the snout. The opening of the sinistral spiracle is directed posterodorsally at a point on the midline about midway on the length of the body. The anal tube is short and dex- tral. The caudal musculature is moderately heavy and extends nearly to the tip of the acutely rounded tail. The fins are moderately shallow; the ventral fin is not as deep as the dorsal fin which does not extend onto the body. At midlength of the tail, the depth of the caudal musculature is slightly greater than the depth of either fin (fig. 201B). The body is dull tan with dark brown flecks and the tail is cream with brown flecks and spots. The fins are transparent and the dorsal fin is heavily flecked with brown. In preservative, the body is dark brown with faint light flecks laterally. The caudal muscu- lature is creamy tan with brown flecks. The mouth is ventral and medium-sized; its width is equal to about one-half of the greatest width of the body. Deep lateral folds are present in the lips. The lips are bordered by two rows of small papillae. The beaks are moderately robust and bear short, robust ser- rations. The upper beak forms a broad arch with moderately long, slender lateral pro- cesses. The lower beak is broadly V-shaped. There are two upper and five lower rows of teeth. The upper rows are long; in most in- dividuals the second lower row is narrowly interrupted medially and in some specimens the first upper row is interrupted. The first four lower rows are nearly as long as the upper rows, but the fifth lower row is notice- ably shorter. In some tadpoles, the first lower tooth row is narrowly interrupted medially (fig. 202B). Mating Call: Dr. Kraig Adler (in litt.) described the call of Hijla pinorum as "a fair- ly loud, guttural, coarse and low-pitched 'Brraaa' or 'Braa-aaaa,' lasting a second or less. Calls were single and repeated at 3-4 minute intervals at the least." Natural History: The only calling males of this species were obtained at San Andreas de la Cruz, Guerrero, Mexico, in June, 1964, by Kraig Adler, who found them calling from low vegetation along a shallow stream.10 At that same locality, I found tadpoles in quiet pools in the stream and numerous metamor- phosing young on low vegetation along the streams. Completely metamorphosed young have snout-vent lengths of 19.7 and 21.0 mm. Remarks: Taylor (1937, p. 46) named thjla pinorum on the basis of one immature 1,1 Adler revisited this locality on December 22, 1969, and obtained a large series of calling males and one clasping pair. Also, 12 specimens were taken from streams south of Puerto Gallo, Guerrero. At these last two localities Adler obtained specimens of an apparently unnamed species that resembles H. pinorum in size and color pattern but differs in call and flash colors. 406 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 TABLE 39 Measurements of Tadpoles of Hyla pinorum, with Means in Parentheses, in Relation to Developmental Stages. Stage N Body Length Tail Length Total Length 25 25 7.0-12.5 12.0-24.0 19.5-36.0 (10.5) (17.3) (27.8) 26 . 13 12.0-13.0 19.0-22.5 31.0-35.5 (12.5) (20.9) (33.3) 27 9 12.0-14.5 20.5-26.0 32.5-40.5 (13.4) (25.9) (36.4) 28 8 12.0-15.0 23.0-27.5 35.5-41.0 (13.9) (24.7) (38.6) 29 5 13.5-14.5 22.5-25.5 37.0-39.5 (14.0) (24.3) (38.3) 30 3 13.0-15.0 23.0-24.5 36.0-39.5 (14.3) (23.8) (38.2) 31 1 14.5 26.5 41.0 32 2 14.5-15.0 26.0-27.0 40.5-42.0 (14.8) (26.5) (41.3) 33 3 15.0-15.5 23.0-27.0 38.0-42.0 (15.2) (25.2) (40.3) 34 2 14.0-15.5 26.5-28.0 40.5-43.5 (14.8) (27.2) (42.0) 35 1 16.0 28.5 44.5 36 4 15.0-16.0 26.5-28.5 41.5-44.0 (15.5) (27.3) (42.8) 37 6 14.5-17.0 26.0-28.0 41.0-44.5 (15.8) (26.7) (42.4) 38 ...... 3 14.0-16.5 25.5-27.0 41.0-43.5 (15.5) (26.5) (42.0) 39 2 16.5 29.5-32.5 46.0-49.0 (31.0) (47.5) 40 6 15.0-17.5 24.5-32.5 40.5-50.0 (16.3) (28.3) (44.7) 41 11 15.0-18.5 23.0-33.5 38.0-50.5 (17.2) (29.2) (46.5) 42 2 15.5-19.5 25.0-31.0 40.5-50.5 (17.5) (28.0) (45.5) 43 ..... 3 15.0-17.0 19.5-23.0 36.0-40.0 (16.2) (21.2) (37.3) 44 3 16.5-20.0 7.5-15.5 24.5-32.0 (17.8) (11.5) (29.3) 45 1 16.0 8.5 24.5 1970 DUELLMAN: HYLID FROGS 407 1 r ^—Metatarsal Tubercles 45 - 40 35 30 £ 25 E ?20 15 10 Total Tail Body Mouthparts Complete; L = 1/2D\ » — »___ */ ^L=2D 24 26 28 30 32 34 36 38 40 42 44 46 Developmental Stages Fig. 204. Relative rate of growth in tadpoles of Hyla pinorum as correlated with developmental stages (table 39). Points are means of measurements given in table 1; formulas for the limb bud refer to its length ( L ) in relation to the basal diameter ( D ) . 408 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 female from Agua del Obispo, Guerrero. Duellman (1960c, p. 191) considered die holotype of Hyla pinorum to represent an im- mature individual of Ptijchohyla leonhard- schultzei. The acquisition of fresh material and adults of Hyla pinorum definitely show that this species is valid. Etymology: The specific name is the genitive of the Latin pinus, meaning pine, and refers to the habitat of this species at Agua del Obispo, Guerrero, Mexico. Distribution: Hyla pinorum is known from cloud forest and pine-oak forest at ele- vations between 700 and 1070 meters on the Pacific slopes of the Sierra Madre del Sur from central Guerrero to southwestern Oaxa- ca, Mexico (fig. 205). See Appendix 1 for the locality records of the IS specimens examined. 100° 98° 18° .* i >> i 'y s i • i 16° 0 100 i KILOMETERS i I8C !6< 100° 98° Fig. 205. Distribution of Hyla pinorum. The Hyla sumichrasti Group Definition: The members of this group are small, stream-breeding species with broad flat heads and pointed snouts; males attain a maximum snout-vent length of 28 mm. and females, 33 mm. The dorsum is yellow, tan, gray, or green with or without dark brown or black flecks or reticulations. The thighs are dull yellow. The palpebral membrane is clear. The fingers are about one-third webbed, and the toes are about three-fourths webbed. Dermal fringes are lacking; an abbreviated axillary membrane is present. The tympanum is barely distinct. Males have single, median, subgular vocal sacs and horny nuptial excres- cences on the pollices. The skull is charac- terized by a large frontoparietal fontanelle and massive nasals that are broadly in con- tact medially (fig. 206). The sphenethmoid is short and broad. The anterior arm of the squamosal is long and extends half of the distance to the maxillary. The quadratojugal is absent, and the palatine is slender. The prevomer is broad and bears a small dentig- erous process. The median ramus of the pterygoid is moderately robust but not in bony contact with the prootic. Prevomerine teeth are few in number or absent. The tad- poles have depressed bodies and long muscu- lar tails. The mouth is immense and is bor- dered by three complete rows of papillae. There are three upper and seven lower rows of teeth. The mating call consists of a series of short, quickly repeated notes. The haploid number of chromosomes is 12 (known only in H. smaragdina). Composition: Two species (H. smarag- dina and sumichrasti) comprise the group, which is endemic to Mexico. Of the two spe- cies, 317 preserved frogs, seven skeletons, and six lots of tadpoles have been examined. Fie. 206. Dorsal (A) and lateral (B) views of the skull of Hyla sumichrasti, K.U. No. 59929. X 6. 1970 DUELLMAN: HYLID FROGS 409 Comments: The two species comprising the Hyla sumichrasti group are alike, and differ from other Middle American hylids, by having tadpoles with immense mouths and 3/7 tooth rows. Neither by cranial characters nor by larval features can the members of this group be closely associated with other Middle American stream-breeding hylids. The skulls of Hyla sumichrasti and smaragdina bear some resemblance to those of the frogs of the Hyla smitliii group. On the other hand, the pond-inhabiting tadpoles of the Hyla smitliii group are distinctly different from the tadpoles of the sumichrasti group. Perhaps the sumichrasti group represents a stream- adapted stock that evolved from the smitliii group or its ancestral stock. The differences between Hyla sumichrasti and smaragdina are slight, and perhaps the two are conspecific. However, a large hiatus exists between their geographic ranges. Seem- ingly, suitable habitat is present in this hiatus (Guerrero and western Oaxaca), but despite extensive collecting in Guerrero, neither spe- cies has been found there. Hyla sumichrasti (Brocchi) Excrodonta sumichrasti Brocchi, 1879, p. 20 [holo- type, formerly in M.N.H.N., presumably lost (fide Kellogg, 1932, p. 181), from Santa Efigenia, Oaxaca, Mexico; Francis Sumichrast collector], Brocchi, 1882. Hylella platycephala Cope, 1879 [syntypes, U.S.N.M. No. 10037 (five specimens) from Santa Efigenia, Oaxaca, Mexico; Francis Sumichrast collec- tor]. Hylella sumichrasti: Boulenger, 1882a, p. 366. Gunther, 1901 (1885-1902), p. 286. Kellogg, 1932, p. 181. Smith and Taylor, 1948, p. 76. Hyla sumichrasti: Kieden, 1923, p. 249. Diagnosis: This small species has a uni- formly yellow, tan, gray, or pale green dor- sum and dull yellow thighs. The head is broad and flat, and the snout is pointed in dorsal profile. Hyla sumichrasti can be dis- tinguished from other small yellow or tan hy- lids having yellow thighs by having an indis- tinct tympanum and by lacking a tarsal fold, extensive axillary membrane, and dorsolateral light stripes or dark dorsal markings. Hyla smaragdina differs by having a distinct tym- panum and a tarsal fold and by usually hav- ing dark flecks or reticulations on the dorsum. Description: Males of this small species at- tain a maximum snout-vent length of 27.7 mm., and females reach 33.0 mm. In a series of 23 males from 2 kilometers northwest of Pueblo Nuevo Solistahuaean, Chiapas, Mexico, the snout-vent length is 24.8 to 27.7 (mean, 26.2) mm.; the ratio of tibia length to snout-vent length is 0.463 to 0.556 (mean, 0.505); the ratio of foot length to snout-vent length is 0.390 to 0.460 ( mean, 0.424 ) ; the ratio of head length to snout-vent length is 0.295 to 0.327 (mean, 0.311); the ratio of head width to snout-vent length is 0.285 to 0.324 (mean, 0.305), and the ratio of the diameter of the tympanum to that of the eye is 0.593 to 0.864 ( mean, 0.688 ) . In 17 females from the same locality, the snout-vent length is 28.5 to 33.0 (mean, 30.2) mm. In most proportions, the females do not differ significantly from the males, except that in the females, the ratio of the diameter of the tympanum to that of the eye is 0.652 to 0.952 (mean, 0.723). To the west, in Oaxaca, specimens are somewhat smaller. For example, in 18 males from 11.8 kilometers south of Chivela, Oaxaca, Mexico, the snout-vent length is 23.8 to 26.0 (mean, 25.2) mm., and in 13 males from Portillo Nejapa, Oaxaca, the snout-vent length is 22.7 to 25.0 (mean, 23.9) mm. There are no significant differences in proportions, although one individual from Portillo Nejapa has a tym- panum that is equal in size to the eye. The head is as wide as the body; the top of the head is flat. The interorbital distance is about twice the width of the eyelid. In dorsal profile, the snout is somewhat pointed; in lateral profile the snout is low and round. The snout is long; the nostrils are barely pro- tuberant and are situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is rounded, and the loreal region is barely concave. The lips are thin and barely flared. A thin dermal fold extends posteriorly from the eye, above the tympanum, and downward to a point above the insertion of the arm. The fold ob- scures the upper one-third to one-half of the tympanum. The posteroventral edge of the tympanum is covered by skin in some speci- mens; otherwise, the tympanum is distinct and separated from the eye by a distance somewhat less than the diameter of the tym- panum. 410 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fie. 207. Hands and feet of species in the Hyla sumichrasti group. A and C. Hyla sumichrasti, K.U. No. 57860. B and D. Hyla smaragdina, K.U. No. 75329. X 6. The arms are short and robust; an abbre- viated axillary membrane is present. Tuber- cles are lacking on the ventrolateral edge of the forearm, but a distinct transverse dermal fold is present on the wrist. The fingers are short and stout and bear moderately large discs; the width of the disc of the third finger is nearly equal to the diameter of the tym- panum. The subartieular tubercles are large and round; none is bifid. The supernumerary tubercles are low, round, and indistinct in some specimens. A tripartite palmar tubercle is present. The prepollex is moderately en- larged and in breeding males bears a horny nuptial excrescence. The hands are about one-third webbed (fig. 207A). The webbing is vestigial between the first and second fin- gers, but connects the second finger from the base of the penultimate phalanx to the mid- dle of the antepenultimate phalanx of the third finger and on to the base of the penulti- mate phalanx of the fourth. The legs are relatively short and robust; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to the posterior corner 1970 DUELLMAN: HYLID FROGS 411 of the eye. A thin transverse dermal fold is present on the heel, but a tarsal fold is lack- ing. The inner metatarsal tubercle is long, low, flat, and barely visible from above; the outer metatarsal tubercle is absent. The toes are moderately long and slender and bear discs that are slightly smaller than those on the fingers. The subarticular tubercles are small and round, and the supernumerary tu- bercles are indistinct and present only on the proximal segments of each digit. The toes are about three-fourths webbed (fig. 207C). The webbing extends from the distal end of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the distal end of the penultimate pha- lanx of the second to the base of the penulti- mate phalanx of the third, from the distal end of the penultimate phalanx of the third to the base of the penultimate phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly near the level of the upper edges of the thighs; a short anal sheath is present. The skin on the belly and throat is granular, whereas that on other surfaces is smooth. The tongue is broadly cordifonn, shallowly notched posteriorly ( notched anteriorly in some specimens) and barely free behind. Of 151 specimens examined, 77 lack dentigerous processes on the prevomers. When present, the processes are short, transverse ridges be- tween the small, round choanae. Dentigerous processes lacking teeth are present in 38 specimens, whereas one to three teeth are present on each process in 36 specimens. The vocal slits extend from the midlateral base of the tongue towards the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla sumichrasti varies from a nearly uniform pale green or grayish green to yellowish tan or pale brown (pi. 59, figs. 1 and 2). Color notes taken on living specimens from 2 kilometers northwest of Pueblo Nuevo Solistahuaean, Chiapas, Mexico, revealed that the dorsum varied from pale yellowish tan to olive-brown or medium brown. Minute darker flecks are present on the dorsum in some individuals. The loreal region is dark olive-green, and the anterior and posterior surfaces of the thighs are pink- ish tan. Notes on specimens from 11.8 kilo- meters south of Chivela, Oaxaca, Mexico, in- dicate that the dorsum was pale yellow and the belly was white; the vocal sac in males is yellow. In specimens from Portillo Nejapa, Oaxaca, Mexico, the dorsum was pale brown or pale green at night. By day, the dorsum varied from brown, grayish tan, yellowish tan, pale green, dark green, to olive-green. The belly is white, and the vocal sac is bright yel- low. The flanks are pale yellow and the an- terior and posterior surfaces of the thighs are dull yellowish tan. The iris is bronze with black reticulations. In preservative, all specimens are pale brown, creamy tan, or grayish tan above. The ventral surfaces are uniform creamy tan. Tadpoles: A typical tadpole in develop- mental stage 37 has a body length of 12.8 mm. and a total length of 38.5 mm. The body is depressed and about 20 per cent wider than deep. The body is tapered posteriorly in dor- sal view. In dorsal profile, the snout is bluntly rounded, and in lateral profile the snout slopes gradually from the eyes to the anterior tip, which is rounded. The eyes are moderately large and directed dorsolaterally. The nostrils are situated about one-third of the distance from the eyes to the tip of the snout and are directed anterodorsally. The opening of the sinistral spiracle is slightly below the midline and at a point about two-thirds from the dis- tance of the snout to the posterior edge of the body. The cloacal tube is long and dex- tral. The caudal musculature is robust and extends nearly to the tip of the rounded tail. The caudal fins are low, the dorsal fin is slightly deeper than the ventral fin. At mid- length of the tail, the depth of the caudal musculature is equal to the depth of the dorsal fin, which does not extend onto the body (fig. 208A). The dorsum is grayish tan; bronze flecks are present on the flanks and caudal muscu- lature. The caudal fins are transparent with faint gray blotches. The iris is pale bronze. In preservative, the tadpoles are gray with a pale creamy tan tail that is marked by faint gray blotches. The ventral mouth is extremely large; it is as wide as the body. Definitive lateral 412 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fig. 208. Tadpoles of species in the Hyla sumichrasti group. A. Hyla sumichrasti, K.U. No. 104163. B. Hyla smaragdina, K.U. No. 78989. X 3. folds are lacking. The mouth is completely bordered by three rows of papillae; the pa- pillae in the two outer rows are minute, whereas the papillae in the inner row are large and blunt. The beaks are relatively small and bear minute serrations. The upper beak forms a low arch with long, slender lateral processes. The lower beak is V-shaped. There are three upper rows and six or seven lower rows of teeth. The upper rows are equal in length; the third upper row is nar- rowly interrupted in some specimens. The lower rows are complete, with the exception of the seventh row, which is fragmented in all specimens in which it is present. The first four lower rows are about equal in length, but the succeeding rows are progressively shorter (fig. 209A). Starrett (1960a, p. 28) described recently hatched tadpoles: "Larvae with external gills hatched on June 29, and by July 3, they were heavily pigmented. They measured 10-12 mm., and their mouth discs were very large." She stated that some of the tadpoles that were 10 to 12 mm. in length had tooth row formu- las of 3/4 or 3/5. Mating Call: The call of Hyla sumi- chrasti consists of a series of quickly repeated notes: "haah-haah-haah." Each call group consists of 17 to 29 (mean, 24) notes. The first one to five notes in each call group are monophasic; successive notes are biphasic. The analysis of the calls of three individuals shows the duration of the notes is 0.18 to 0.21 (mean, 0.198) of a second. The pulse rate varies from 70 to 75 (mean, 71) pulses per second. The note repetition rate varies from 125 to 170 (mean, 154) notes per sec- ond. The fundamental frequency varies from 79 to 115 (mean, 94) cycles per second. In Fig. 209. Mouths of tadpoles of the Hyla sumi- chrasti group. A. Hyla sumichrasti, K.U. No. 104163. B. Hyla smaragdina, K.U. No. 78989. X 10. 1970 DUELLMAN: HYLID FROGS 413 two individuals, the dominant frequency is at 3160 and 3220 cycles per second; another emphasized harmonic is present between 1800 and 2000 cycles per second. In the third in- dividual, the dominant frequency is at 1830 cycles per second (pi. 18, fig. 2). Natural History: Hyla sumichrasti in- habits subhumid oak and pine forests, where it breeds in rocky streams. In the dry season, individuals are most commonly found in ar- boreal bromeliads. Prior to the onset of the rains at a locality 2 kilometers northwest of Pueblo Nuevo Solistahuacan, Chiapas, Mex- ico, on June 15, 1960, 40 specimens of this small frog were obtained from bromeliads in pine-oak forest. As many as five frogs were taken from one bromeliad. On July 6, 1956, I found males calling from small bushes and rocks in and along a swift rocky stream 11.8 kilometers south of Chivela, Oaxaca, Mexico. Calling males were found at Portillo Nejapa, Oaxaca, Mexico, on August 9, 1966; at that locality the frogs were calling from rocks in the bed of a small stream in dry pine-oak forest. Starrett (1960, p. 28) found calling males along a rocky stream on June 27, 1957, 19 kilometers north of Arriaga, Chiapas, Mexico. She stated: "At this time eggs and 20-mm. tadpoles were collected from the same stream. The eggs, about 50 in number, were fastened in one layer to a piece of dead leaf wedged in among rocks in the water. They were uniform grayish white in color." Remarks: The application of the specific names sumichrasti and platycephala was dis- cussed by Boulenger ( 1891 ) and Kellogg (1932). The specimens forming the basis for Brocchi's description of Exerodonta sumi- chrasti and for Cope's Hylella platycephala were all collected by Francis Sumichrast. Brocchi's description appeared before that of Cope. Duellman (1960b) discussed the diagnos- tic characters of this species as given by Taylor (1943) and Taylor and Smith (1945). He noted that the species had been incorrect- ly diagnosed as having no vocal sacs, rarely having prevomerine teeth, and as having a relatively smooth throat. Etymology: The specific name is a pat- ronym for Francis Sumichrast, who collected the type series. Distribution: Hyla sumichrasti inhabits the Pacific slopes of eastern Oaxaca (east and west of the Isthmus of Tehuantepec) and western Chiapas, and the slopes of the Chia- pan highlands, principally in the Rio Grijalva drainage, Mexico (fig. 210). This species oc- curs at elevations between 200 and 1675 meters. See Appendix 1 for the locality records of the 172 specimens examined. Hyla smaragdina Taylor Hyla s hi a r a a d i n a Taylor, 1 940a [holotype, F.M.N.H. No. 100009 (formerly E.H.T.-H.M.S. No. 17534) from 6 kilometers east of Cojumatlan, Micho- acan, Mexico; Edward H. Taylor collector]. Smith and Taylor, 1948, p. 90. Duellman, 1961c, p. 51 [synony- mized Hi/lella azteca Taylor, 1943, with Hyla smarag- dina Taylor, 1940a]. Hylella azteca Taylor, 1943, p. 49 [holotype, U.I.M.N.H. No. 25044 (formerly E.H.T.-H.M.S. No. 17525) from Tepoztlan, Morelos, Mexico; Edward H. Taylor collector], Hyla azteca: Gorham, 1963, p. 21. Diagnosis: This small species has a yel- lowish tan or green dorsum usually marked with dark flecks or reticulations. This colora- tion, together with a pointed snout, a broad and flat head, distinct tympanum, tarsal fold and the absence of an extensive axillary mem- brane, distinguish smaragdina from other Mid- dle American hylids. Hyla sumichrasti has an indistinct tympanum and lacks a tarsal fold. Description: Males of this species attain a maximum snout-vent length of 26 mm., and females reach 28 mm. In a series of 25 males from Santa Lucia, Sinaloa, Mexico, the snout- vent length is 23.0 to 25.9 (mean, 24.4) mm.; the ratio of tibia length to snout-vent length is 0.434 to 0.519 (mean, 0.470); the ratio of foot length to snout-vent length is 0.352 to 0.439 (mean, 0.400); the ratio of head length to snout-vent length is 0.278 to 0.339 (mean, 0.309); the ratio of head width to snout- vent length is 0.251 to 0.292 (mean, 0.268), and the ratio of the diameter of the tympanum to that of the eye is 0.542 to 0.857 ( mean, 0.683 ) . One adult female from the same locality has a snout-vent length of 28.0 mm.; in this specimen the ratio of the diameter of the tympanum to that of the eye is 0.957. The head is as wide as the body; the top of the head is flat, and the interorbital dis- 414 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 104° 100° 96° 22° 22° V' > '->'; -• -n •-''"> - / o") *X'<- r'\ ) '"X^\ / X n \ \ <^-~j-\.'i X JX ""'< w--, \ • H sumichrasti o H smaragdina 18° •v. 1 V- \ ! .' "V .' 18° 0 100 300 ^\ \ • • • ••#: KILOMETERS ~~V'" 104° 100° 96° Fig. 210. Distribution of Htjla smaragdina and Hyla sumichrasti. tance is noticeably greater than the width of the upper eyelid. In dorsal profile, the snout is pointed; in lateral profile, the snout is acutely rounded and slightly protruding. The snout is long, and the nostrils are situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is round; the loreal region is barely concave, and the lips are only slightly flared. A thin dermal fold extends posteriorly from the eye, above the tympanum and to a point above the insertion of the arm. The fold obscures the upper edge of the tympanum, which otherwise is distinct and separated from the eye by a distance less than the diameter of the tympanum. The arms are moderately short; an ab- breviated axillary membrane is present. Tu- bercles are absent on the ventrolateral edge of the arm, but a distinct transverse dermal fold is present on the wrist. The fingers are moderately short and bear large discs; the width of the disc of the third finger is equal to the diameter of the tympanum. The sub- articular tubercles are large and round; none is bifid. Supernumerary tubercles, if present, are indistinct. A tripartite palmar tubercle is present. The prepollex is moderately en- larged and in breeding males bears an ex- tensive horny nuptial excrescence. The fin- gers are about one-third webbed (fig. 207B). The webbing is vestigial between the first and second fingers; it extends from the base of the penultimate phalanx of the second finger to the base of the antepenultimate phalanx of the third and from the middle of the antepenultimate phalanx of the third to the base of the penultimate phalanx of the fourth finger. The legs are short and robust; the heels of the adpressed limbs barely over- lap. The tibiotarsal articulation extends to the tympanum. A weak transverse dermal fold is present on the heel, and a moderately strong tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is small, round, and ovoid in outline. The outer metatarsal tubercle, if present, is small and indistinct. The toes are moderately long and bear discs that are about equal in size to those on the fingers. The subartieular tubercles are 1970 DUELLMAN: HYLID FROGS 415 large and round; the supernumerary tubercles usually are absent. The toes are about three- fourths webbed (fig. 207D). The webbing extends from the distal end of the penultimate phalanx of the first toe to the base of the penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the middle of the antepenultimate phalanx of the third; from the base of the disc of the third to the base of the penulti- mate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the level of the upper edges of the thighs. A short anal sheath is present. The skin on the throat and belly is granular; elsewhere, it is smooth. The tongue is broadly cordi- form, emarginate or shallowly notched be- hind, and barely free posteriorly. The den- tigerous processes of the prevomers are small transverse ridges between the small round choanae. One to three teeth are present on each ridge. The vocal slits extend from the midlateral base of the tongue to the angles of the jaws. The vocal sac is single, median, subgular, and moderately distensible. The general coloration of Hyla smaragdina is pale green, yellowish green, or yellowish tan with or without dark flecks on the dorsum (pi. 59, fig. 3). All specimens from the north- ern part of the range (Sinaloa) are pale green or yellowish green with dark brown or black flecks on the dorsum. There is a distinct, narrow black line from the nostril to the eye; a white anal stripe is present. Individuals from the southern part of the range (Colima and Michoacan) tend to lack the dark flecks on the dorsum, which is either pale green or yellowish tan. The groin and anterior and posterior surfaces of the thighs are uniformly pinkish tan; the belly is white. The iris is gold with black flecks or reticulations. In preservative, the dorsum varies from pale grayish tan to dull brown with or with- out dark flecks. The anterior and posterior surfaces of the thighs are creamy tan, and the venter is creamy white. Tadpoles: A typical tadpole in develop- mental stage 37 has a body length of 13.0 mm. and a total length of 36.2 mm. The body is greatly depressed and is about 30 per cent wider than deep. In dorsal profile the body tapers posteriorly; when viewed from above the snout is broadly rounded, and laterally it is steeply inclined to the mouth. The eyes are moderately small and directed dorsolater- ally. The nostrils are noticeably closer to the eyes than to the tip of the snout. The open- ing of the sinistral spiracle is directed pos- teroventrally at a point below the midline and about two-thirds of the distance from the tip of the snout to the posterior edge of the body. The anal tube is long and dextral. The caudal musculature is robust and extends nearly to the tip of the acutely rounded tail. The caudal fins are low; the dorsal fin does not extend onto the body and is deepest at about midlength of the tail, where its depth is less than that of the caudal musculature. Throughout its length the dorsal fin is deeper than the ventral fin (fig. 208B). In preservative, the body is gray; the cau- dal musculature is creamy white, and the fins are transparent. Small gray blotches are pres- ent on the caudal musculature and fins. The mouth is immense; its width is equal to the greatest width of the body. Lateral folds are absent. The lips are completely bor- dered by two rows of small papillae; medial to these is a row of widely spaced larger pa- pillae dorsally and a row of more closely spaced larger papillae along the ventral lip. The beaks are well developed and bear fine pointed serrations. The upper beak forms a low arch with long slender lateral processes; the lower beak is roughly V-shaped. There are three upper rows of teeth; these are about equal in length, and the third upper row is narrowly interrupted medially. There are six or seven lower rows of teeth, of which the first five are approximately equal in length and continuous. The sixth row is noticeably shorter and fragmented in most specimens, whereas the seventh row, if present, is frag- mented in all specimens (fig. 209B). Mating Call: Recordings of the call of Hyla smaragdina are not available, but I heard the species call at Pomaro, Michoacan, Mex- ico, on July 13, 1951. The call is a nasal "haah- haah-haah" repeated quickly and constantly for as long as 30 seconds. Natural History: Hyla smaragdina in- habits tropical semi-deciduous forest and pine- 416 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 oak forest, where there is a definite dry sea- son. Individuals have been found in brome- liads in the dry season. In the rainy season, the frogs congregate along small rocky streams. The males call from rocks in or at the edges of the stream. The tadpoles de- velop in the streams. Remarks: Duellman (1961c, p. 51) noted that Taylor (1940a, p. 18) named this species on the basis of immature individuals collect- ed near Cojumatlan, Michoaean. Later, Tay- lor (1943, p. 49) named Hylella azteca from Tepoxtlan, Morelos. Duellman showed that the type specimens of both named taxa were representative of a single species. Duellman (1958b, p. 8) extended the range of the species to Colima, and McDiar- mid (1963, p. 7) described the tadpoles from Santa Barbara, Nayarit. Etymology: The specific name is Greek meaning emerald green and refers to the dor- sal color of this small frog. Distribution: Hyla smaragdina occurs at elevations of about 100 to 1500 meters on the Pacific slopes of the Sierra Madre Occidental, Sierra de Coaleoman, and the Cordillera Vol- cania from southern Sinaloa southward to Michoaean and Morelos, Mexico (fig. 210 ).n See Appendix 1 for the locality records of the 158 specimens examined. The Hyla mixomaculata Group Definition: The members of this group are small, stream-breeding species; males at- tain a maximum snout-vent length of 36 mm. and females, 37 mm. The dorsum is tan or brown with darker brown or black flecks or blotches. The dorsal surfaces of the limbs are banded, and the posterior surfaces of the thighs are tan or brown. The palpebral mem- brane is clear. The fingers are no more than one-third webbed, and the toes are at least three-fourths webbed. Dermal fringes and appendages are lacking on the limbs; an ab- breviated axillary membrane is present. The tympanum is concealed (ventral edge barely evident in some mixomaculata) . Males lack 11 On July 19, 1968, Dr. Robert G. Webb collected this species at 13 kilometers southeast of Iziicar de Matamoros, Puebla, thereby extending the known range farther eastward from Morelos in the upper Balsas Basin. vocal slits and horny nuptial excrescences on the pollices. The cranial elements are moder- ately well ossified; a large frontoparietal fon- tanelle is present. The sphenethmoid is large, acuminate anteriorly, and extends anteriorly between the nasals, which are moderately large, widely separated medially, and broadly sutured to, or overlapping, the sphenethmoid. The quadratojugal is absent; the squamosal is not in bony contact with the crista parotica, and the anterior arm of the squamosal extends only about one-half of the distance to the maxillary. The medial ramus of the pterygoid does not have a bony articulation with the prootic. Prevomerine teeth are present. The known tadpoles have large ventral mouths bearing seven upper and 11 lower rows of teeth. Males do not call, and the number of chromosomes is unknown. Composition: Four species (H. mixe, mixomaculata, nuhicola, and pellita) comprise the group, which is endemic to cloud forests in Veracruz and Oaxaca, Mexico. Thirty-three preserved frogs, four skeletons, and three lots of tadpoles have been examined. Comments: Duellman (1965a, p. 34) sug- gested that Hyla mixe and nuhicola were closely related to mixomaculata. These three species occur on the Atlantic slopes of the Sierra Madre Oriental in Mexico, where mixo- maculata and nuhicola are sympatric in cen- tral Veracruz. Hyla mixe and nuhicola are alike in having fully webbed feet and nasals that overlap the sphenethmoid, whereas in mixomaculata, the feet are about three-fourths webbed, and the nasals are broadly sutured to the sphenethmoid (fig. 211). Hyla mixe and nuhicola apparently evolved from a mixo- 7naculata-\ike ancestral stock, which probably also gave rise to pellita, a species on the Pa- cific slopes of Oaxaca having nasals and feet like mixomaculata, but differing chiefly in coloration. The loss of voice in this group, as in other montane stream hylids, such as the Hyla bis- tincta group and Plectrohyla, seems to be correlated with the apparent lack of need for voice in these frogs, which throughout the year live along the streams. Hyla mixomaculata Taylor Hyla mixomaculata Taylor, 1950, p. 274 [holotype, 1970 DUELLMAN: HYLID FROGS 417 Fig. 211. Dorsal views of skulls: cola, U.M.M.Z. No. S-2244. x 6. A. Hijla mixomaculata, K.U. No. 26778. B. Hyla nubi- K.U. No. 26777 from Coscomatepec, Veracruz, Mexico; Walter W. Dalquest collector]. Diagnosis: This moderately small species has transverse bars on the dorsal surfaces of the limbs and feet about three-fourths webbed; it lacks a tympanum. Two of the other Mexican Hyla lacking a tympanum ( mixe and nubicola) have fully webbed feet. Hyla mixe has numerous transverse bars on the limbs and robust hands and feet, and nu- bicola lacks bars on the thighs. The webbing in mixomaculata is similar to that in pellita and pinorum; pellita is smaller and has a yel- lowish tan, instead of a reddish brown, dor- sum, whereas pinorum lacks transverse bars on the thighs and has large tubercles below the anal opening. Description: Males of this moderately small species attain a maximum snout-vent length of 29.1 mm., and females reach 36.6 mm. In a series of three males from central Veracruz, Mexico, the snout-vent length is 28.5 to 29.1 (mean, 28.9) mm.; the ratio of tibia length to snout-vent length is 0.491 to 0.521 (mean, 0.508); the ratio of foot length to snout-vent length is 0.459 to 0.474 (mean, 0.465); the ratio of head length to snout-vent length is 0.351 to 0.355 (mean, 0.353), and the ratio of head width to snout-vent length is 0.326 to 0.354 (mean, 0.343). The head is as wide as the body, and the top of the head is flat. In dorsal profile, the snout is bluntly rounded; in lateral profile, it is truncate. The snout is moderately short; the nostrils are barely protuberant at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is angu- lar; the loreal region is barely concave, and the lips are moderately thick and barely flared. A moderately heavy dermal fold ex- tends posteriorly from the eyes to a point above the insertion of the arm. The tym- panum is concealed beneath the skin; in a few specimens, the lower edge of the tympanum is barely evident. The arms are moderately long and slender; an abbreviated axillary membrane is present. A low, glandular, dermal fold extends along the ventrolateral edge of the forearm, and a weak, transverse dermal fold is present on the wrist. The fingers are moderately short and stout and bear moderately large discs; the width of the disc on the third finger is equal to about one-third of the diameter of the eye. The subarticular tubercles are large and coni- cal; the distal tubercles on the third and fourth fingers are bifid in some specimens. The supernumerary tubercles are small and indistinct. The palmar tubercle is low and tri- partite. An elongate tubercle is present on the pollex. The prepollex is only moderately en- larged and, in males, does not bear a nuptial excrescence. The fingers are about one-third webbed (fig. 212A). The webbing is vestigial between the first and second fingers and ex- tends from the base of the penultimate pha- lanx of the second to the base of the ante- penultimate phalanx of the third, and from 418 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Fie. 212. Hands of the species in the Hyla mixomaculata group. A. Hyla mixomaculata, U.M.M.Z. No. 119159. B. Hyla pellita, K.U. No 100970. C. Hyla nubicola, K.U. No. 88031. D. Hyla mixe, K.U. No. 87110. X 5. the middle of the antepenultimate phalanx of the third to the base of the penultimate pha- lanx of the fourth finger. The legs are mod- erately long and slender; the heels of the adpressed limbs overlap by about one-third of the length of the shank. The tibiotarsal articulation extends to the eye. A distinct, transverse dermal fold is present on the heel, and an elevated, thin tarsal fold extends the full length of the tarsus. The inner metatar- sal tubercle is small, flattened, ovoid, and barely visible from above. An outer meta- tarsal tubercle is absent. The toes are mod- erately long and slender and bear discs that are noticeably smaller than those on the fin- gers. The subartieular tubercles are moder- ately small and subcorneal, and the super- numerary tubercles are minute and indistinct in many specimens. The toes are about three- fourths webbed (fig. 213A). The webbing extends from the middle of the penultimate phalanx of the first toe to the base of the 1970 DUELLMAN: HYLID FROGS 419 Fig. 213. Feet of the species in the Hyla mixomaculata group. A. Hi/la mixomacu- lata, U.M.M.Z. No. 119159. B. Hyla pellita, K.U. No. 100970. C. Hyla nubicola, K.U. No. 88031. D. Hyla mixe, K.U. No. 87110. x 5. 420 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 penultimate phalanx of the second, from the distal end of the penultimate phalanx of the second to the middle of the penultimate pha- lanx of the third, from the middle or distal end of the penultimate phalanx of the third to the middle of the penultimate phalanx of the fourth and on to the distal end of the penultimate phalanx of the fifth toe. The anal opening is directed posteriorly at the level of the dorsal surfaces of the thighs. A short, unmodified anal sheath is present, and numerous tubercles are present below the anal opening. The skin on the dorsum and on the ventral surfaces of the arms and shanks is smooth, that on the throat, belly, and ventral surfaces of the thighs is granular. The tongue is cordifonn, barely free behind, and shallowly notched posteriorly or not. The dentigerous processes of the prevomers are narrowly separated, elliptical, transverse pro- cesses between the posterior margins of the small round choanae. There are three to five teeth on each process. Vocal slits and a vocal sac are absent. The general coloration of Hyla mixomacu- lata is tan or pale reddish brown with darker irregular spots or blotches on the back and transverse bars on the limbs (pi. 58, fig. 5). The coloration of the dorsum is highly varia- ble. Usually the dorsum is pale brown with a slight pinkish or reddish cast. The dorsal dark blotches are dark reddish brown. The dorsal surfaces of the limbs are tan with reddish brown transverse bars and flecks. A narrow, dark brown postorbital line is usu- ally present. The loreal region is pale tan flecked with dark brown. The inguinal region and the posterior and anterior surfaces of the thighs are deep yellow or tan. The under surfaces of the thighs are deep yellow or tan. The under surfaces of the hind limbs are pale yellow. The webbing on the foot is pale gray. A narrow, white anal stripe is bordered be- low by a narrow, dark brown line. The belly is white, and the iris is coppery bronze with dark brown or black reticulations, especially peripherally. In preservative, the dorsum is pale tan or brown with darker brown spots and blotches on the back and narrow transverse bars on the forearms, thighs, shanks, and feet. The venter is creamy white. The toes and webbing are pale tan. Some individuals have scattered white flecks on the dorsum. Tadpoles: A series of tadpoles obtained from a stream 3 kilometers southwest of Hua- tusco, Veracruz, Mexico are referred to this species. Two tadpoles having well-developed hind limbs have the distinctive transverse bars of Hyla mixomaculata. Several tadpoles in developmental stage 25 are present. The largest of these has a body length of 11.5 mm. and a total length of 32.3 mm. The largest tadpole is in devel- opmental stage 41 and has a body length of 19.0 mm. and a total length of 49.5 mm. A typical tadpole in developmental stage 33 has a body length of 14.4 mm. and a total length of 40.2 mm. The body is slightly de- pressed and slightly wider than deep. In dorsal profile, the snout is broadly rounded; in lateral profile, it is inclined anteroventrally and acutely rounded terminally. The eyes are moderately large, widely separated, and directed dorsolaterally. The nostrils are small and directed anterolaterally at a point about one-third of the distance from the eyes to the snout. The opening of the sinistral spiracle is directed posterodorsally at a point slightly below the midline about two-thirds of the distance from the snout to the posterior end of the body. The anal tube is short and dex- tral. The caudal musculature is heavy and does not extend to the tip of the rounded tail. The caudal fins are moderately shallow, and the dorsal fin does not extend onto the body. The dorsal fin is slightly deeper than the ventral one. At midlength of the tail, the depth of the musculature is only slightly less than the combined depth of the dorsal and ventral fins (fig. 214). In life the tadpoles were pale yellowish brown above and had a transparent venter. In preservative, the dorsum is dark brown, and the venter is pale gray. The caudal mus- culature is tan; reddish brown spots are pres- ent on the dorsal part of the musculature and on the dorsal fin. The mouth is large, nearly as wide as the body. A slight lateral fold is present. The mouth is completely bordered by one row of small papillae. The beaks are moderately slender and lack serrations. The upper beak is in the form of a broad arch lacking lateral 1970 DUELLMAN: HYLID FROGS 421 Fig. 214. Presumed tadpole of Hyla mixomaculata, U.M.M.Z. No. 119652. X 3. processes; the lower beak is broadly V-shaped. There are seven upper and 10 or 11 lower rows of teeth, all of which are long and com- plete, except the seventh upper row, which is narrowly interrupted medially (fig. 215). Tadpoles in developmental stage 25 all have seven upper rows of teeth and 10 lower rows. The outermost rows in some individ- uals are poorly developed. Tadpoles in de- velopmental stage 33 all have seven well-de- veloped upper rows and 10 or usually 11 lower rows. In the tadpoles in developmen- tal stage 41 the outer rows of teeth have begun to degenerate, so that the first and second upper rows and the tenth and eleventh lower rows are fragmentary. Mating Call: The absence of vocal slits and a vocal sac precludes the presence of a mating call in this species. Natural History: Most of the known specimens of Hyla mixomaculata have been obtained in the dry season (December, Janu- ary, and February). At that time, individuals are most frequently encountered in bromeliads '^^JX&tev&^Xii&iW&ii1**^ Fig. 215. Mouth of presumed tadpole of Hyla mixomaculata, U.M.M.Z. No. 119652. x 8. in the cloud forest. On January 26, 1958, I obtained three specimens from the leaves of bushes at the edge of a stream in Barranca Metlac, Veracruz, at night. Tadpoles were obtained on March 27, 1959; the tadpoles adhered to rocks in fast- moving parts of a clear stream. Remarks: The tympanum is more nearly visible in this species than in others of this group. Perhaps, this is indicative of a rela- tively primitive position within the group. Hyla mixomaculata and nubicola occur sympatrieally in central Veracruz, Mexico. Both species have been obtained from brome- liads from the same locality on the same day. Etymology: The specific name is derived from the Latin mixtus, meaning mix, and the Latin maculatus, meaning spots, and refers to the interconnected spots on the dorsum. Distribution: Hyla mixomaculata occurs in cloud forest at elevations between 900 and 1500 meters in central Veracruz, Mexico (fig. 216). See Appendix 1 for the locality records of the 25 specimens examined. Hyla pellita Duellman Hyla pellita Duellman, 1968a, p. 568 [holotype, K.U. No. 100970 from 33 kilometers north of San Gabriel Mixtepec, Oaxaca, Mexico, 1675 meters; William E. Duellman and Linda Trueb collectors]. Diagnosis: This moderately small species has transverse bars on the limbs and has the feet about three-fourths webbed; it lacks a tympanum. Two of the other Mexican Hyla lacking a tympanum (mixe and nubicola) have fully webbed feet. Hyla pellita differs from mixomaculata by being smaller and by having a yellowish tan, instead of a reddish brown, dorsum. Hyla pinorum also lacks a tympanum but differs from pellita by having 422 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 a proportionately larger head, no transverse bands on the thighs, and large tubercles be- low the anal opening. Description: Males of this small species attain a maximum snout-vent length of 27.3 98° 96° 18° i ! \ _> '• i '-,>■■■'' r i. r s a / • fi /■ \ 6 100 18° \l KILOMETERS > i i i v.. 1 c • H. mixomaculata o //. pellita g A 16° i ■ 16° 98° 96° Fie. 216. Distribution of Hyla mixomaculata and Hyla pellita. mm., and females reach 31.6 mm. In a sample of three males from the Pacific slopes of the Sierra Madre del Sur in Oaxaca, Mexico, the snout-vent length is 25.2 to 27.3 (mean, 26.4) mm.; the ratio of tibia length to snout-vent length is 0.476 to 0.513 (mean, 0.497); the ratio of foot length to snout-vent length is 0.420 to 0.429 (mean, 0.426); the ratio of head length to snout-vent length is 0.317 to 0.327 (mean, 0.321), and the ratio of head width to snout-vent length is 0.333 to 0.34] (mean, 0.337). Two females from the same locality have snout-vent lengths of 28.6 and 31.6 mm. The head is nearly as wide as the body, and the top of the head is flat. In dorsal profile, the snout is bluntly rounded; in lateral profile, it is truncate but rounded above. The snout is moderately long; the nostrils are barely protuberant and situated at a point about four-fifths of the distance from the eyes to the tip of the snout. The canthus is angu- lar; the loreal region is slightly concave, and the lips are thin and moderately flared. A thin dermal fold extends posteriorly from the posterior edge of the eye to a point above the insertion of the arm. The tympanum is not visible externally. The arms are moderately long and slender; an abbreviated axillary membrane is present. A weak tubercular fold is present on the ventrolateral edge of the forearm, but a dis- tinct transverse dermal fold is absent on the wrist. The fingers are moderately short and stout and bear rather small discs; the width of the disc on the third finger is equal to about one-third of the diameter of the eye. The subarticular tubercles are moderately large, round, and flattened; the distal tuber- cles on the third and fourth fingers are bifid. The supernumerary tubercles are large, round, and present in a single row on the proximal segments of each digit. The palmar tubercle is low, flattened, and diffuse. The prepollex is barely enlarged and in males lacks a nuptial excrescence. The fingers are about one-third webbed (fig. 212B). Webbing is absent be- tween the first and second fingers but extends from the base of the penultimate phalanx of the second to the base of the antepenultimate phalanx of the third, from the middle of the antepenultimate phalanx of the third to the distal end of the antepenultimate phalanx of the fourth finger. The legs are moderately long and stout; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articula- tion extends to the eye. A low, thin tarsal fold extends the full length of the tarsus. The inner metatarsal tubercle is flat, ovoid, and partly visible from above. The outer meta- tarsal tubercle is absent. The toes are mod- erately short and bear discs that are slightly smaller than those on the fingers. The sub- articular tubercles are small and round; the supernumerary tubercles are small, flattened, and irregularly arranged on the proximal seg- ments. The toes are about three-fourths webbed (fig. 213B). The webbing extends from the base of the disc of the first toe to the middle of the penultimate phalanx of the second, from the base of the disc of the second to the middle of the penultimate pha- lanx of the third, from the base of the disc of the third to the base of the penultimate 1970 DUELLMAN: HYLID FROGS 423 phalanx of the fourth and on to the base of the disc of the fifth toe. The anal opening is directed posteriorly at the level of the dorsal surfaces of the thighs. A short anal sheath has a membra- nous connection with the posterodorsal sur- faces of the thighs. The anal opening is bor- dered below by vertical dermal folds and a few small tubercles. The skin on the dorsum and the ventral surfaces of the arms and shanks is smooth, that on the throat, chest, and belly is heavily granular. The tongue is cordiform, deeply notched posteriorly, and barely free behind. The dentigerous processes of the prevomers are short, narrowly sepa- rated elevations between the small, round choanae. Males have three or four teeth on each elevation, and females have three to five teeth on each elevation. Vocal slits and a vocal sac are absent. The general coloration of Hyla pcllita is pale yellowish tan above with faintly darker tan or olive-brown markings (pi. 56, fig. 6). When active at night, the frogs are yellowish tan with reddish brown flecks. By day the coloration changed to pale brown with a dull olive-green interorbital bar, blotches on the dorsum, transverse bars on the limbs, and scattered flecks on the dorsum. The hands, feet, and anterior and posterior surfaces of the thighs are dull yellow. The belly is white. A creamy, white stripe is present on the outer edge of the forearm and another is present on the outer edge of the tarsus. A short, distinct white stripe is present above the anal opening. The iris is pale bronze. In preservative, the dorsum is pale tan with a dark brown mark in the occipital region and dark brown marks on the back. The anterior and posterior surfaces of the thighs lack pigment. The dorsal surfaces of the arms, shanks, and feet are tan with brown transverse bars. The venter is creamy white. All specimens have distinct transverse bars on the limbs; the number of bars on the shank varies from one to four. Two individ- uals are dark brown dorsally; in these the small black flecks are either not visible or are absent; flecks are present on the dorsal sur- faces of four specimens that are tan or pale brown above with darker brown irregular markings. Tadpoles: The tadpoles of Hyla pellita are unknown. Mating Call: The absence of vocal slits and a vocal sac in this species precludes the presence of a call. Natural History: Hyla pellita has been found only along two streams in the cloud forest on the Pacific slopes of the Sierra Madre del Sur in Oaxaca, Mexico. All individuals were found on low vegetation along streams at night. This species has been collected only in the dry season (February); visits to the type locality in the rainy season yielded no specimens. Remarks: Although Hyla pellita is in- cluded in the Hyla mixomaculata group, it possibly is related to Hyla pinomm as well. The latter species also occurs on the Pacific slopes of the Sierra Madre del Sur in Guer- rero and Oaxaca. Hyla pi no mm resembles pellita in size, general coloration, and in the absence of an externally visible tympanum, but differs in certain osteological characters (size of nasals, shape of the anterior end of the sphenethmoid, and in the absence of a quadratojugal ) . Etymology: The specific name is Latin, meaning covered with skin, and alludes to the complete concealment of the tympanum by the skin. Distribution': Hyla pellita is known only from elevations between 1500 and 1700 meters on the Pacific slopes of the Sierra Madre del Sur in Oaxaca, Mexico (fig. 216). See Appendix 1 for the locality records of the six specimens examined. Hyla nubicola Duellman Hyla nubicola Duellman, 1964a, p. 225 [holotype, U.M.M.Z. No. 118160 from a stream 3 kilometers southwest of Huatusco, Veracruz, Mexico, 1325 meters; William E. Duellman collector]. Diagnosis: This moderately small species has barred limbs and fully webbed feet; it lacks a tympanum. Hyla nubicola can be dis- tinguished from all other tympanum-less Mid- dle American Hyla, except mixe, by its fully webbed feet. The latter species has more robust hands and feet, many narrow bands on the limbs and pale webbing on the feet, whereas nubicola lacks bars on the thighs and dark webbing on the feet. 424 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 Description: Males of this moderately small species attain a maximum known snout- vent length of 36.7 mm., and females reach 37.3 mm. In three males from central Vera- cruz, Mexico, the snout-vent length is 32.2 to 36.7 (mean, 34.2) mm.; the ratio of tibia length to snout-vent length is 0.485 to 0.515 (mean, 0.501); the ratio of foot length to snout-vent length is 0.433 to 0.450 (mean, 0.439); the ratio of head length to snout- vent length is 0.302 to 0.326 (mean, 0.313), and the ratio of head width to snout-vent length is 0.313 to 0.326 (mean, 0.320). The one known female has a snout-vent length of 37.3 mm. The head is as wide as the body, and the top of the head is flat. In dorsal profile, the snout is truncate, but the entire head is round- ed; in lateral profile, the snout is truncate and barely rounded above. The canthus is angu- lar; the loreal region is barely concave and the lips are moderately thin and barely flared. A moderately heavy dermal fold extends pos- teriorly from the eye to a point above the insertion of the arm. The tympanum is cov- ered with skin and is not visible externally. The arms are moderately long and slender; an abbreviated axillary membrane is present. A low tubercular fold is present on the ven- trolateral edge of the forearm, and a weak transverse dermal fold is present on the wrist. The fingers are short and stout and bear large discs; the width of the disc on the third fin- ger is equal to about one-half of the diameter of the eye. The subarticular tubercles are large and round; none is bifid. The supernu- merary tubercles are small and irregularly arranged on the proximal segments of each digit. The palmar tubercle is moderately large, flat, and partially bifid. A single, ellipti- cal tubercle is present on the slightly en- larged prepollex, which lacks a nuptial ex- crescence. The fingers are about one-fourth webbed (fig. 212C). The webbing is lack- ing between the first and second fingers but extends from the base of the penultimate pha- lanx of the second to the base of the ante- penultimate phalanx of the third and from the middle of the antepenultimate phalanx of the third to the base of the penultimate phalanx of the fourth finger. The legs are moderately long and slender; the heels of the adpressed limbs overlap by about one-fourth of the length of the shank. The tibiotarsal articulation extends to the anterior corner of the eye. A weak tarsal fold extends about two-thirds of the length of the tarsus. The inner metatarsal tubercle is elliptical, flat, and partly visible from above. The outer metatar- sal tubercle is absent. The toes are moder- ately short and robust and bear discs that are noticeably smaller than those on the fin- gers. The subarticular tubercles are round and bluntly conical; the supernumerary tu- bercles are minute. The toes are fullv webbed (fig. 213C). The anal opening is directed posteriorly at the level of the upper edges of the thighs. A short, thick anal sheath is present, and small tubercles are present ventrolateral to the anal opening. The skin on the dorsum and ventral surfaces of the arms and legs is smooth; that on the throat, chest, belly, and proximal posteroventral surfaces of the thighs is weakly granular. The tongue is cordiform, wider than long, shallowly notched posterior- ly, and barely free behind. The dentigerous processes of the prevomers are narrowly sepa- rated, elliptical ridges between the moder- ately large, ovoid choanae. There are three or four teeth on each process. Vocal slits and a vocal sac are absent. The general coloration of Hijla nubicola is pale reddish brown or olive-tan with faintly darker markings on the back and limbs (pi. 5S, fig. 8). The coloration in life varies from olive-tan with olive-brown markings to olive- brown with dark brown markings or reddish tan with reddish brown markings. The mark- ings on the dorsum consist of small, irregular spots or blotches and scattered dark flecks. There are three or four dark transverse bars on the shank, and there are faint indications of transverse markings on the forearms and feet. The flanks are pale grayish tan or yel- lowish tan with scattered brown flecks. The venter is white; a few grayish brown flecks are present on the edge of the chin. The webbing of the feet is dark brown or dark gray. The anterior and posterior surfaces of the thighs are dull yellow or yellowish tan. A short white anal stripe is present. Small creamy white flecks are scattered on the dorsum in all specimens. The iris is coppery bronze. 1970 DUELLMAN: HYLID FROGS 425 In preservative, the dorsum is grayish tan with irregular dark brown blotches and spots and narrow dark brown transverse bars on the shanks. The thighs are grayish brown above; the anterior surfaces of the thighs and the ventral surfaces of the hind limbs are creamy tan and the ventral surfaces of the feet and webbing are dark brown. The flanks are pale grayish tan with brown flecks, and the belly and chin are creamy white with grayish brown flecks on the chin. Tadpoles: The tadpoles of Hyla mibicola are unknown. Mating Call: The absence of vocal slits and a vocal sac apparently precludes a voice in this species. Natural History: The few specimens of Hyla mibicola have been found in the vicinity of small streams in cloud forest. Individuals have been found on vegetation overhanging the streams at night and in bromeliads by day. Remarks: No additional information is available on this species other than that pro- vided in the description of the species by Duellman (1964a). Etymology: The specific name is derived from the Latin nubes, meaning cloud, and the Latin suffix -cola, meaning an inhabitant; the name refers to the cloud forest where this species lives. Distribution: Hyla mibicola is known only from cloud forests at elevations between 900 and 1400 meters on the Atlantic slopes of the Sierra Madre Oriental in central Vera- cruz, Mexico (fig. 217). See Appendix 1 for the locality records of the six specimens examined. Hyla mixe Duellman Hyla mixe Duellman, 1965a, p. 32 [holotype, K.U. No. 87110 from a stream 4.2 kilometers by road south of Campamento, Vista Hermosa, Oaxaca, Mexico, 1800 meters; David A. Johnson collector]. Diagnosis: This moderately small species has strongly barred dorsal surfaces of the limbs and fully webbed feet; it lacks a tym- panum. Hyla mixe can be distinguished from all other tympanum-less Middle American spe- cies of Hyla by having many narrow dark bars on the limbs. Hyla mibicola is the only other species that lacks a tympanum and has 98° 96° 18' U V i \ . r> \ ■) '-■-■ws---.:> >' \ 6 ioo 1 - '■>.._, 1 KILOMETERS < • V i • H. nubicola o H. mixe o ».,._•' v. i 1 -Iff 98° 96° Fig. 217. Distribution of Hyla nubicola and Hyla mixe. fully webbed feet. In comparison with mibi- cola, mixe has more numerous and narrower transverse bars on the limbs, a proportionately broader head with thicker lips, more robust hands and feet, and paler webbing on the feet. Description: Males of this moderately small species are unknown; females attain a maximum known snout-vent length of 33.9 mm. In the two known females, the ratio of tibia length to snout-vent length is 0.495 and 0.508; the ratio of foot length to snout- vent length is 0.457 and 0.470; the ratio of head length to snout-vent length is 0.297 and 0.318, and the ratio of head width to snout- vent length is 0.330 and 0.352. The head is as wide as the body, and the top of the head is flat. In dorsal and lateral profile, the snout is bluntly rounded. The snout is moderately long, and the nostrils are barely protuberant and situated at a point about three-fourths of the distance from the eyes to the tip of the snout. The canthus is acutely rounded; the loreal region is barely concave, and the lips are moderately thick and barely flared. A moderately heavy der- mal fold extends posteriorly from the eye to a point above the insertion of the arm. The tympanum is covered by skin and is not visi- ble externally. The arms are moderately short and ro- bust; an abbreviated axillary membrane is present. A distinct tubercular dermal fold is present on the ventrolateral edge of the forearm, and a distinct transverse dermal 426 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 1 fold is present on the wrist. The fingers are short and broad and bear moderately large discs; the width of the disc on the third finger is equal to about one-half of the diam- eter of the eye. The subarticular tubercles are large and round; the distal tubercle on the fourth finger is slightly bifid. The super- numerary tubercles are small, subcorneal, and present on the proximal segments of the digits. The palmar tubercle is moderately large and bifid; a large elliptical tubercle is present on the pollex. The prepollex is barely enlarged. The fingers are about one-third webbed (fig. 212D ) . The webbing is vestigial between the first and second fingers, but extends from the base of the penultimate phalanx of the second to the base of the antepenultimate phalanx of the third, and from the middle of the ante- penultimate phalanx of the third to the base of the penultimate phalanx of the fourth finger. The legs are moderately long and heavy; the heels of the adpressed limbs over- lap by about one-third of the length of the shank. The tibiotarsal articulation extends to the middle of the eye. A short dermal fold is present on the heel. The tarsal fold is weak and extends about one-third of the length of the tarsus. The inner metatarsal tubercle is large, flat, triangular in outline, and not visible from above. The outer metatarsal tubercle is lacking. The toes are moderately long and bear discs that are only slightly smaller than those on the fingers. The subarticular tuber- cles are round, and the supernumerary tu- bercles are moderately large and round. The toes are fully webbed' (fig. 213D); a thin fold of skin extends along the outer edges of the first and fifth toes. The anal opening is directed posteriorly at the level of the upper surfaces of the thighs. A short anal sheath is present, and small tubercles are present below the anal opening. The skin on the dorsal surfaces is slick and smooth; the skin on the ventral sur- faces of the limbs is smooth, and that on the belly and ventral and posterior surfaces of the thighs is granular. The tongue is cordi- form, slightly notched posteriorly, and barely free behind. The dentigerous processes of the prevomers are elliptical ridges between the posterior margins of the small, ovoid cho- anae. There are two or three teeth on each process. The general coloration of Hijla mixe is brown with darker brown markings (pi. 1, fig. 2). At night, the frogs are brown with dark brown markings, but by day they change to have a greenish tan dorsum with olive- green markings. The anterior and posterior surfaces of the thighs are tan, and the web- bing is orange-tan. The venter is creamy yel- low, and the iris is pale silvery green. The dorsal markings consist of irregularly inter- connected spots on the back and many dis- tinct, narrow transverse bars on the limbs. A few brown flecks are present on the flanks. A faint anal stripe is present. In preservative, the dorsum is pale pinkish brown with dark brown markings. The flanks are white with small brown flecks. The proxi- mal surfaces of the upper arm lack pigment, except for a few scattered brown flecks. The thighs are a pale creamy tan anteriorly and posteriorly, and marked with small brown flecks posteriorly. The ventral surfaces of the limbs and webbing are cream, and the belly and chin are white. Tadpoles: A series of tadpoles, presum- ably of this species, was obtained from the type locality, a small stream in the north slope of the Sierra de Juarez in northern Oaxaca, Mexico, on February 16, 1966. The largest preserved tadpole is in developmental stage 32 and has a body length of 13.7 mm. and a total length of 39.0 mm. The body is depressed and slightly wider than deep. The snout is broadly rounded in dorsal profile; in lateral profile, the snout slopes gradually from the nostril to an acutely rounded tip. The eyes are moderately large, widely separated, and directed dorsolaterally. The small nos- trils are directed anterolaterally at a point about one-third of the distance from the eyes to the tip of the snout. The opening of the sinistral spiracle is directed posteriorly at a point slightly below the midline about two- thirds of the distance from the snout to the posterior edge of the body. The anal tube is short and dextral. The caudal musculature is robust and does not quite reach the tip of the rounded tail. The caudal fins are shal- low; at midlength of the tail the depth of the caudal musculature is equal to the com- bined depths of the ventral and dorsal fins. The dorsal fin does not extend onto the body (fig. 218). 1970 DUELLMAN: HYLID FROGS 427 Fig. 21S. Presumed tadpole of Hyla mixe, K.U. No. 104183. x 3. The body is dark brown with golden flecks. The tail is pale cream, and the iris is dull brown. In preservative, the body is dark brown above and dark gray below with small bluish white flecks. The caudal musculature is cream with a few brown blotches, especial- ly dorsally. The fins are transparent, with or without faint reticulations. The mouth is ventral and large; it is wider than the snout and as wide as the widest part of the body. A slight lateral fold is pres- ent in the lips, which are completely fringed by one row of small papillae. A few addi- tional papillae are present laterally. The beaks are slender and nearly smooth; there are no serrations. The upper beak is in the form of a shallow curve and lacks lateral pro- cesses; the lower beak is broadly V-shaped. Typically, there are seven upper rows and 10 or 11 lower rows of teeth. All of the rows are long and extend to the edges of the lips. The seventh upper row is narrowly interrup- ted medially, and in some specimens the first lower row is narrowly interrupted medially. The teeth in the outer rows are short and less completely keratinized than those in the inner rows (fig. 219). Small tadpoles in develop- Fic. 219. Mouth of presumed tadpole of Hyla mixe, K.U. No. 104183. x 8. mental stage 25 and having body lengths of less than 11 mm. have only 10 lower rows of teeth. Larger tadpoles in developmental stage 32 had 11 rows. The eleventh row is fragmented in some specimens. In two tad- poles there are fragments of an eighth upper row present. The assignment of these tadpoles to Hyla mixe is done on the basis of their similarity of the supposed tadpoles of Hyla mixomacu- lata. Furthermore, these tadpoles were ob- tained at the type locality of Hyla mixe, a stream known to be inhabited by three other species of stream-breeding hylids, the tad- poles of all of which are known. Natural History: The two known adults of Hyla mixe were found at night on limbs of bushes overhanging a cascading mountain stream in cloud forest. The tadpoles were obtained from the rocky stream, where they were common in midparts of the stream with rocky or gravel bottoms. The tadpoles hold on to the lee-sides of rocks with their large mouths. When disturbed they sought refuge between and under large rocks. When the tadpoles were placed in a glass container they adhered to the sides of the container with their mouths. Remarks: Hyla mixe seems to be most closely related to Hyla nubicola from which it differs by having more robust limbs, hands, and feet and by having numerous and dis- tinct transverse bands on all segments of the limbs. Etymology: The specific name refers to the Mixe Indians that inhabit the lower moun- tainous regions in northern Oaxaca. Distribution: Hyla mixe is known only from a stream at an elevation of 1800 meters on the northern slopes of the Sierra de Juarez in northern Oaxaca, Mexico (fig. 217). See Appendix 1 for the locality records of the three specimens examined. QL668.E24 D84 *» V ' I Ik hylid Frogs ol Mkklh \ Harvard MCZ Library MM I 3 2044 062 318 852 Date Due