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ELLE An rarer er Rem Ато ОК DS RADA MA Air RIA dz da Po hun CE “ CNP WORT ER TEIL EL} vor da BEM e Ам PPT TT ns CLS un teks > SA en Ема ANN m ев A Pye Leena ssi ar RER (HELD EURE PT IE ET, ке дерини вре не STE EZ Meat OS CET Cutie ts Hutt Dr ел an млм POIL Ах ELLES ATEN аа ул роль À E antrat ма TOC a rn A DIME ANN a er MAMAN re кала ENCRES than sete мА NSS rasen Brn arm ive thn Moa nt D ne PROBE SAFT EFT TE йа mabe Adar Rome Nets ce tenet te eT AA PER TEE AENA RTE LE TAPA eet ' SN A A AA CRUEL верит stator nf tee D DO ET bakes CELLES LS DA En a de Lars rare ПР print CEE LEE San matey N Lae Fara ET LL Done naan Ae PTE mm PA EL EL И ELEC CLR CRETE a aa tn Dana À Ae ела ae eke III Cee ee PACE RTL Nahe a O aa A A A N Pe Uren TEN Mae ESEL ET seinen PPT Rasa AA PPT ги." ее att ик паев et в ить е PEER OA = PA IR VE разом tra tie MONTE DITES pon EL We CE PRES PRIT CPL is Helen tn han 205 HARVARD UNIVERSITY e Library of the Museum of Comparative Zoology gr sie i os u u u — = u Er Kirn o à o y | oa eres Уи чт тс wht? ао; eduecat $e aver yiut 21 TVeL Заирид tf) VOL yedwesgee Tr VOL yteusdst Ут eves yiot TE evel vem af ever лойщезаее er Peet Liege 55 UBCL FaupuA cf _ FRS saut ty [Bes zednsäse € SCI uud, 55 SBel земебА в! све Yisurdet $5 Еве зэчмезаав €: `$8е1 dossM ес 801 Зачрик es авег vis e 2301 fork Y 9881 1odrosad CI 2801 vistas ег 8301 envt Rz 8801 zadnensd af озер ET NT $ MALACOLOGIA International Journal of Malacology Revista Internacional de Malacologia Journal International de Malacologie Mennynabonuul Журнал Малакологии Internationale Malakologische Zeitschrift Vol Vol Vol Vol Vol Publication dates . 28, No . 29, No. . 29, No . 80, No ЗМ ne a 12 . 1- a 2 2 19 January 1988 28 June 1988 16 Dec. 1988 1 Aug. 1989 29 Dec. 1989 9 Vl, IMJ. I JAN 05 1990 1909 | HARVARD UNIVERSITY MALACOLOGIA ; \ International Journal of Malacology _ Revista Internacional de Malacologia Journal International de Malacologie À Международный Журнал Малакологии D. TR Internationale Malakologische Zeitschrift MALACOLOGIA Editor-in-Chief: GEORGE M. DAVIS Editorial and Subscription Offices: Department of Malacology The Academy of Natural Sciences of Philadelphia Nineteenth Street and the Parkway Philadelphia, Pennsylvania 19103, U.S.A. Co-Editors: EUGENE COAN CAROL JONES California Academy of Sciences Vasser College San Francisco, CA Poughkeepsie, NY Assistant Managing Editor: CARYL HESTERMAN Associate Editors: e | ANNE GISMANN University of Michigan Maadi Ann Arbor = Egypt MALACOLOGIA is published by the INSTITUTE OF MALACOLOGY, the Sponsor Members of which (also serving as editors) are: KENNETH J. BOSS, President JAMES NYBAKKEN, President-Elect Museum of Comparative Zoology Moss Landing Marine Laboratory Cambridge, Massachusetts California JOHN BURCH, Vice-President CLYDE F. E. ROPER Smithsonian Institution Washington, D.C. W. D. RUSSELL-HUNTER Syracuse University, New York SHI-KUEI WU University of Colorado Museum, Boulder MELBOURNE R. CARRIKER University of Delaware, Lewes GEORGE M. DAVIS Secretary and Treasurer CAROLE S. HICKMAN University of California, Berkeley Participating Members EDMUND GITTENBERGER JACKIE L. VAN GOETHEM Secretary, UNITAS MALACOLOGICA Treasurer, UNITAS MALACOLOGICA Rijksmuseum van Natuurlijke Koninklijk Belgisch Instituut Historie voor Natuurwetenschappen Leiden, Netherlands Brussel, Belgium Emeritus Members J. FRANCIS ALLEN, Emerita ROBERT ROBERTSON Environmental Protection Agency The Academy of Natural Sciences Washington, D.C. Philadelphia, Pennsylvania ELMER G. BERRY, NORMAN F. SOHL Germantown, Maryland U.S. Geological Survey Reston, Virginia Copyright © 1989 by the Institute of Malacology ED РЕ ТТ ee af р у р | | 1989 EDITORIAL BOARD J. A. ALLEN Marine Biological Station Millport, United Kingdom E. E. BINDER Museum d'Histoire Naturelle Genève, Switzerland A. J. CAIN University of Liverpool United Kingdom P. CALOW University of Sheffield United Kingdom A. H. CLARKE, Jr. Portland, Texas, U.S.A. B. C. CLARKE University of Nottingham United Kingdom R. DILLON College of Charleston SC, U.S.A. C. J. DUNCAN University of Liverpool United Kingdom E. FISCHER-PIETTE Muséum National d'Histoire Naturelle Paris, France Ve ЕВЕТТЕВ University of Reading United Kingdom E. GITTENBERGER Rijksmuseum van Natuurlijke Historie Leiden, Netherlands EZGIUSTI Università di Siena, Italy A. N. GOLIKOV Zoological Institute . Leningrad, U.S.S.R. S. J. GOULD Harvard University Cambridge, Mass., U.S.A. A. V. GROSSU Universitatea Bucuresti Romania T. HABE Tokai University Shimizu, Japan R. HANLON Marine Biomedical Institute Galveston, Texas, U.S.A. A. D. HARRISON University of Waterloo Ontario, Canada J. A. HENDRICKSON, Jr. Academy of Natural Sciences Philadelphia, PA, U.S.A. K. E. HOAGLAND Association of Systematics Collections Washington, DC, U.S.A. B. HUBENDICK Naturhistoriska Museet Göteborg, Sweden S. HUNT University of Lancaster United Kingdom R. JANSSEN Forschungsinstitut Senckenberg, Frankfurt am Main, Germany (Federal Republic) R. N. KILBURN Natal Museum Pietermaritzburg, South Africa M. A. KLAPPENBACH Museo Nacional de Historia Natural Montevideo, Uruguay J. KNUDSEN Zoologisk Institut & Museum Kobenhavn, Denmark A. J. KOHN University of Washington Seattle, U.S.A. Y. KONDO Bernice P. Bishop Museum Honolulu, Hawaii, U.S.A. A. LUCAS Faculté des Sciences Brest, France C. MEIER-BROOK Tropenmedizinisches Institut Tübingen, Germany (Federal Republic) H. K. MIENIS Hebrew University of Jerusalem Israel J. E. MORTON The University Auckland, New Zealand J. J. MURRAY, Jr. University of Virginia Charlottesville, U.S.A. R. NATARAJAN Marine Biological Station Porto Novo, India J. OKLAND University of Oslo Norway T. OKUTANI University of Fisheries Tokyo, Japan W. L. PARAENSE Instituto Oswaldo Cruz, Rio de Janeiro Brazil J. J. PARODIZ Carnegie Museum Pittsburgh, U.S.A. W. F. PONDER Australian Museum Sydney R. D. PURCHON Chelsea College of Science & Technology London, United Kingdom OZ. Academia Sinica Qingdao, People's Republic of China N. W. RUNHAM University College of North Wales Bangor, United Kingdom S. G. SEGERSTRÂLE Institute of Marine Research Helsinki, Finland G. A. SOLEM Field Museum of Natural History Chicago, U.S.A. F. STARMÜHLNER Zoologisches Institut der Universität Wien, Austria У. |. STAROBOGATOV Zoological Institute Leningrad, U.S.S.R. W. STREIFF Universite de Caen France J. STUARDO Universidad de Chile Valparaiso T. E. THOMPSON University of Bristol United Kingdom S. TILLIER Museum National d’Histoire Naturelle Paris, France R. D. TURNER Harvard University Cambridge, Mass., U.S.A. J. A. van EEDEN Potchefstroom University South Africa N. H. VERDONK Rijksuniversiteit - Utrecht, Netherlands B. R. WILSON Dept. Conservation and Land Management Netherlands, Western Australia H. ZEISSLER Leipzig, Germany (Democratic Republic) A. ZILCH Forschungsinstitut Senckenberg Frankfurt am Main, Germany (Federal Republic) MALACOLOGIA, 1989, 31(1): 1-140 AN ENDEMIC RADIATION OF HYDROBIID SNAILS FROM ARTESIAN SPRINGS IN NORTHERN SOUTH AUSTRALIA: THEIR TAXONOMY, PHYSIOLOGY, DISTRIBUTION AND ANATOMY By W.F. Ponder, R. Hershler*, and B. Jenkins, The Australian Museum, Sydney South, NSW, 2000, Australia CONTENTS INTRODUCTION The mound springs—a brief description Geomorphology and water chemistry Spring groups and complexes Climate MATERIALS AND METHODS Taxonomy Taxonomic rationale Materials Methods Characters Anatomy Physiology Materials Methods RESULTS Taxonomy Fonscochlea Fonscochlea (Wolfgangia) Trochidrobia Anatomy Anatomical description of Fonscochlea accepta Anatomical description of Trochidrobia punicea Physiology DISCUSSION Evolution and relationships of fauna Geological history Relationships of mound-spring inver- tebrates Evolution of species within mound springs Dispersal Environmentally-induced variation Ecology and behaviour Community structure Physiology Hydrobiid fauna Absence of fauna Conservation ACKNOWLEDGMENTS REFERENCES APPENDIX 1 List of stations List of springs not sampled Stations at which no hydrobiids were collected Locality maps APPENDIX 2 Tables of measurements ABSTRACT Artesian springs between Marree and Oodnadatta contain an endemic fauna of hydrobiid snails that have undergone an adaptive radiation in which habitat parti- tioning and size displacement are clearly evident. Ten new species in two new en- demic genera, Fonscochlea and Trochidro- bia, are described. Three of the species of Fonscochlea are divided into a total of six geographic forms, which are not formally named. Two geographic forms are restricted to single springs, the remainder being found in several springs, spring groups, or com- plexes of springs. Fonscochlea is divided in to two subgenera, Fonscochlea s.s. contain- ing five species and Wolfgangia with a single species. Both genera are represented in most springs, with up to five taxa present in single springs in the Freeling Springs Group and in some of the other springs in the northern part of the spring system. As many as four taxa are present in most other springs. The pat- tern of one or two sympatric species of Troch- idrobia, a large, amphibious species of “Present address, United States National Museum of Natural History, Washington, D.C., 20560 U.S.A. 2 PONDER, HERSHLER & JENKINS Fonscochlea, one large aquatic species of Fonscochlea and a small aquatic species of Fonscochlea is established in most of the springs in the area. Some of the factors lead- ing to the evolution and maintenance of this diversity are discussed. A subjective classification, based on shell, opercular and anatomical characters, was tested phenetically using discriminate analy- sis. Simple physiological experiments were carried out on some of the taxa to test for the effects of temperature, submergence, desic- cation, increased salinity, reduced dissolved oxygen, and responses to light. All taxa showed a wide range of tolerance to salinity and temperature but the small animals were more susceptible to desiccation than the large ones. Varying responses to light and submergence were obtained but all taxa showed reduced activity in deoxygenated water. The anatomy of the type species of both genera is described in detail. Fonscochlea is unique in having two equal-sized sperm sacs in the female that are probably derived from the bursa copulatrix and, as in Trochidrobia, which has a single sperm sac, the seminal receptacle is lost. The endemic snails, together with the un- usual endemic crustaceans sympatric with them, and their unusual community structure, give the springs special interest, both from the scientific and conservation viewpoints. Key words: Mollusca, Hydrobiidae, springs, endemics, taxonomy, physiology, anatomy, speciation, sympatry, habitat partitioning INTRODUCTION The most nearly permanent type of water body in an arid environment is probably an artesian spring (Naiman, 1981). The habitat provided by an artesian spring in this situation is analogous to that of an island. Each spring is typically separated by arid land providing as marked a discontinuity of habitat as the sea does to terrestrial organisms. Artesian springs are typically permanent, within a mod- erate time scale, perhaps in the order of thou- sands to even millions of years for spring sys- tems but tens to hundreds of years for individual springs, and usually provide a rea- sonable diversity of habitats. Given these conditions one might expect genetic differen- tiation of populations in separate springs and some habitat partitioning allowing similar spe- cies to coexist. Studies of the faunas of arid- zone artesian springs have sometimes re- vealed spectacular examples of speciation and habitat partitioning. The best docu- mented examples are of the fishes of the western deserts in the United States and northern Mexico (Minckley, et al., 1986), par- ticularly of the Death Valley system (Soltz & Naiman, 1978). Studies of these fishes have provided insight into the nature of the speci- ation process (Turner, 1974; Soltz & Hirsh- field, 1981), biogeography relative to drain- age history (Hubbs & Miller, 1948; Hubbs et al., 1974; Smith, 1978) and adaptation to di- verse spring-fed habitats (Naiman & Soltz, 1981). Natural water bodies in arid lands, such as springs, water in caves and marshes, are fre- quently refugia for relict biota. There are nu- merous examples, particularly amongst fishes and crustaceans, that are well documented. A spectacular example is the crocodiles in pools in the Ahaggar Mountains of Africa, now sur- rounded by vast desert areas (Cole, 1968). Springs sometimes support diverse faunas that might be partly relictual and partly en- demic radiations. The hydrobiid snails of the Cuatro Cienegas Basin, Coahuila, Mexico, are presumably an example of such a fauna (Tay- lor, 1966a; Hershler, 1984, 1985). Radiations of hydrobiid snails in springs in temperate climates are also known, examples including those in Florida (Thompson, 1968) and parts of Europe (e.g., Radoman, 1983). A spectacular radiation of the related family Po- matiopsidae in Southeast Asia has been well documented by Davis (1979). Bayly and Williams (1973) note that ex- tremely little is known about the biology of Australian springs. This is certainly true for the artesian springs associated with the Great Artesian Basin. Before this study commenced the only animals that had been studied in de- ` tail in artesian springs in arid Australia were the fishes (Glover & Sim, 1978a; Glover, 1982). Recent biological work is summarised by Ponder (1986). The artesian springs in the arid north of South Australia (Figs. 1, 2) were only recently shown to contain a large and interesting biota (Mitchell, 1985; Symon, 1985; Ponder, 1985, 1986). To date the only invertebrates de- scribed from these mound springs are a phreatoicid isopod (Phreatomerus latipes (Chilton, 1922), an ostracode, Nagarawa dirga (DeDeckker, 1979), and a macrostomid flat- worm, the first record of this order from Aus- tralia (Sluys, 1986). Both of the Crustacea are endemic to the springs and belong in mono- typic subfamilies. AUSTRALIAN SPRING HYDROBIIDS 3 FIG. 1. Various springs in the Lake Eyre Supergroup showing some of the morphological diversity. A. Blanche Cup Spring (Stns 8-12), a conical, calcareous mound spring with a crater-like pool. В. Aerial view of part of Hermit Hill Spring Complex showing part of a spring group (Finniss Swamp West) composed of small ground-level springs and some low sand mounds. С. Almost extinct mound in the Blanche Cup Complex, in the Horse Spring Group (stn 748). Snails and crustaceans are abundant in small seeps such as this. D. The Bubbler Spring (stns 13-17), one of the largest flows in the Lake Eyre Supergroup. PONDER, HERSHLER & JENKINS ‘dnosy Buds 2143 exe eu} ui Sexajdwoo Buuds sofew ay] ‘< ‘914 Y Y xo1duo9 Buds 1H SEX 4 с хэ19шоо Suds” д © eluuejBuem RE > a > | (SONIHdS (SONIHdS aan) x3¡dwo9 6и129$ у 1 SE y eue» ela PIO NE (SONIHdS Г NH31S3M HINOS) N А y O ba x3¡duwo9) Buds xajdwod 6и129$ psojsase xajdwo buds vs Aree 2 91343 ened xaıdwoy Suds skemBue13S xa¡dwoy Buuds © PUUBDEIJIJMEIILQIPED ayer L А U = AN NY31S3M HLHON) N A (SONIHdS | / NHIHLHON Sh хаашоо suds Q N (HLHON) | I, À BUUIGIIN ЭНАЗ HV] xejdwo9 Bujid < () уэлебаеу a Л U a (so Bes ON 2 / 7 00000011 185 у xa¡dwoy Suds MH эхеэ4 06 or os ог ибо A dvW N0117907 de TN < ; (SDNINdS VL1YGVNAOO) ce à NN xejdwoy 64129 ——— Fr À WN eNHEPEUPOO AUSTRALIAN SPRING HYDROBIIDS 5 Gastropod molluscs were reported from the mound springs by Mitchell (1980, unpub- lished; 1985) who, on the advice of Dr. В. Smith, to whom the material was sent for iden- tification, recognized the presence of three or possibly four species referable to three or four genera. DeDeckker (1979) also refersto these snails as undescribed endemics, on Smith’s advice. We cannot find any earlier references to these species in the literature, despite their being conspicuous and abundant in most of the springs. A few of the early explorers no- ticed the small fish found in some springs (see review by Glover & Sim, 1978b). Some of the more accessible mound springs were visited in the latter part of the 1970’s by several biologists who made some collections, those of W. Zeidler of the South Australian Museum being the most signifi- cant. His collections and those sent to Dr. B. Smith were made available to one of us (W.F.P.) and field work was carried out in 1981 by W.F.P. and Zeidler. The result of that field investigation, and an additional one the same year by Zeidler, showed the existence of an apparent endemic fauna of hydrobiid snails of considerable diversity. The available information on the mound- spring fauna was reviewed in an Environmen- tal Impact Statement (E.I.S.) for the Olympic Dam Project (Kinhill-Stearns Roger, 1982) and in a supplement to this E.1.S. (Kinhill- Stearns, 1983). The review in the supplement included some new information on the hydro- biid snails provided by two of us (W.F.P., B.W.J.). Because the Olympic Dam Project required water from a borefield located near a large spring complex at Hermit Hill (Fig. 2; Appendix 1, Fig. 62), further biological and hydrological studies were carried out to as- sess the importance of the flora and fauna associated with these springs. This paper has been developed from the report resulting from those studies. A summary of the results of the hydrobiid work appears in the report prepared for Roxby Management Services on the mound springs (Ponder & Hershler, 1984). The importance of the springs and the need for their conservation has been stressed by Casperton (1979), Harris (1981), Symon (1985) and Ponder (1985, 1986). This view has also been strongly supported by the evi- dence accumulated in the reports prepared as a result of the Olympic Dam Project (Kin- hill-Stearns Roger, 1982, Kinhill-Stearns, 1983, 1984). The World Wildlife Fund has re- cently provided funds to fence some springs. The snails present in the mound springs are members of the Hydrobiidae, a world- wide family of prosobranch gastropods that are part of the large, predominantly marine superfamily Truncatelloidea. The hydrobiids were probably derived from brackish-water ancestors in the middle part of the Mesozoic (Ponder, 1988) and some members of the family are still restricted to brackish-water en- vironments. To date the family is known to be represented in Australia by about nine genera and approximately 35 named species, ex- cluding those from the mound springs, al- though recent unpublished work by W.F.P. shows that this fauna is actually much larger. The adaptations of organisms to the diverse and often extremely harsh aquatic environ- ments in deserts are of interest to physiolo- gists as well as ecologists and evolutionary biologists. While a variety of taxa are usually found in such waters, only the desert fishes are well studied in terms of their ecology and physiology (see summaries, Deacon & Minck- ley, 1974; Soltz & Naiman, 1978; Naiman & Soltz, 1981). In areas in which hydrobiid snails have radiated extensively in desert wa- ters, particularly spring systems of North and Central America (Taylor, 1966a, b; Hershler, 1985; Hershler & Landye, 1988) and Australia (Ponder, 1986), their frequent local diversity and high densities suggest that they are trophically important members of desert aquatic communities. Yet there is a paucity of data concerning their ecology and virtually nothing is known of their physiology. Toler- ances to the environmental parameters that often achieve extreme levels in desert waters (e.g., salinity, temperature), have not been studied for any spring-dwelling hydrobiid spe- cies, although some work on South African species of Tomichia, of the related family Po- matiopsidae, has been done (Davis, 1981). This paper commences with an introduc- tory section outlining the main features of the mound springs. The rest of the paper is di- vided into three sections. The first deals with the taxonomy of the hydrobiid snails, followed by a detailed account of the anatomy of the type species of the two genera found in the springs. The results of the physiological work done in the field are presented in the third section. The mound springs—a brief description Geomorphology and water chemistry: The artesian mound springs of South Australia are aligned in an arc running from the far northern 6 PONDER, HERSHLER & JENKINS part ofthe state at Dalhousie Springs, north of Oodnadatta, around the south of Lake Eyre to Lake Frome and Lake Callabonna on the eastern side of the Flinders Ranges. Addi- tional artesian springs are found in western Queensland and were found in the north-west of New South Wales, but these are now mostly extinct (personal observations by W.F.P. and M.A. Habermehl, pers. comm.), presumably as a result of water extraction from the basin by the pastoral industry. The springs are natural discharges from the aqui- fers formed from the Jurassic and Cretaceous sedimentary rocks of the Great Artesian Ba- sin (see Habermehl, 1980, 1982, for geolog- ical details). They occur in a variety of forms, the most common being small mounds result- ing from groundwater precipitates, mainly car- bonates, and fine sediments derived from the aquifer and confining beds. Wind-blown de- bris and plant material also contribute to the mound formation. The mounds are composed primarily of hard travertine or of sediment, or layers of both. They range from virtually flat to large mounds several tens of meters high. The larger mounds are the older springs, the ground-level springs the youngest (Ponder, 1986: Fig. 4). More detailed descriptions of the springs are provided by Watts (1975), Habermehl (1982), Thomson and Barnett (1985), and Ponder (1986). The South Aus- tralian mound springs are the most active and numerous of the artesian springs fed by the Great Artesian Basin (Habermehl, 1982) and are now the best known biologically. The little that is known of Queensland artesian springs is summarised by Ponder (1986). Dalhousie Springs, to the north of Oodna- datta, yields about 95% of the natural dis- charge from the Great Artesian Basin in South Australia (Williams, 1979; Williams & . Holmes, 1978). These springs are, however, outside the present study area, as are some small springs east of Marree to the north and east of the northern Flinders Ranges. Some of these springs contain endemic inverte- brates, including hydrobiids, and these will be dealt with elsewhere. The springs included in this report (Fig. 2; Appendix 1) are located mainly on the Warrina, Billa Kalina and Cur- dimurka 1:250,000 map sheets and a few on the Oodnadatta sheet. They form a zone about 400 km long and as much as 20 km wide between Marree and Oodnadatta (Fig. 2) and are referred to as the Lake Eyre group by Habermehl (1982) and the Lake Eyre Su- pergroup by Ponder (1986). The morphology of the springs in the Lake Eyre Supergroup is diverse (Fig. 1). The springs range from surface seeps (Fig. 1b) to low, conical mounds (Fig. 1a, c) or even small hills. The mounds consist of sand, silt and clay, often cemented by carbonate and over- lain by layers of carbonate (Habermehl, 1980, 1982). The cemented mounds often persist for considerable periods after the springs that formed them have ceased to flow, but the un- consolidated mounds erode rapidly. Some mounds have a crater-like, water-filled de- pression at the top (Fig. 1a), while others have rounded domes (Fig. 1c); both types typically have one or more outlets. Some of the larger, dome-like mounds (e.g., Kewson Hill and the Elizabeth Springs mound) have several small seeps issuing from them. Discharges from most of the springs are small, ranging from about 0.5 litre per sec- ond to 7.5 litres per second at the Bubbler Spring (Fig. 1d) (Cobb, 1975; Williams, 1979; Habermehl, 1982). Despite this, discharge from some springs is sufficient to maintain flows for several hundred metres or, more rarely, a kilometre or more, providing a well- vegetated wetland habitat. Other springs have such a small discharge that they do not maintain an outflow, having only a pool or small swampy area at the head. Others are merely permanently damp patches that might flow occasionally. Some small springs in the Hermit Hill complex (Fig. 1b) have been ob- served flowing on some occasions and are dry on others. The Lake Eyre Supergroup has a total estimated discharge of 100-200 litres per second (Habermehl, 1982), compared with 670 litres per second for Dalhousie Springs (A.F. Williams, 1974; Williams & Holmes, 1978). The depth of the water in the pools and outflows rarely exceeds 2—3 cm and is usu- ally only a few millimetres. The pools and out- flows usually contain sedges but rarely true aquatic vegetation apart from algae. The out- flows are usually narrow trickles with a firm, sandy base and, in the case of the hard mounds, calcareous rock. Our observations indicate that the area of outflow diminishes in summer, presumably owing to increasing evaporation, and some observations suggest that periods of high barometric pressure coincide with reduced water flow (C. Woolard, pers. comm.). Williams and Holmes (1978) have esti- mated that a spring with a small discharge typical of many of the springs in the Lake Eyre AUSTRALIAN SPRING HYDROBIIDS 7 Supergroup, shown on the Curdimurka map sheet, would take about 1000 years to deposit sufficient calcium carbonate to build a hemi- spherical mound three metres high. On this basis some of the larger mounds, such as Kewson Hill, might, even with substantially in- creased flow rates, take several tens of thou- sands of years to form. Forbes (1961) has shown, however, that drilling on mounds in this vicinity reveals that a substantial portion of the mound is formed by the deposition of sand and clay rather than “limestone”, sug- gesting that the calculations by Williams and Holmes (1978) might be invalid. Analyses of the water from the springs in the Lake Eyre Supergroup have been given by Cobb (1975), Williams (1979) and Kinhill- Stearns (1984) and summarized by Haber- mehl (1982). Sodium and bicarbonate are the major ions in springs in the eastern part ofthe Lake Eyre group whereas in springs in the western part the bicarbonate component is small and sodium and chloride ions predom- inate over calcium and sulphate. Total dis- solved solids in most springs range from 2000-4000 ppm, with a few in excess of 5000 ppm, and pH from about 7.1 to 8.1, although a field pH of up to 9.95 has been recorded in recent surveys. The temperatures in the spring vents are constant throughout the year and show a slight increase from east to west ranging from upper teens to mid-twenties (°C) in the east to upper twenties in the west. The salinity increases toward the discharge areas of the Great Artesian Basin. A few springs in the Lake Eyre Supergroup might not originate from the waters of the Great Artesian Basin aquifer, or show signif- icant mixing with sulphate-rich ground-water, as their hydrochemistry is atypical. These springs are located on the faulted edge of the basement rocks and include Kerlatroaboorn- tallina Spring, Talton Springs, Edith Spring, Dead Boy Spring and Pigeon Hill Springs, the last two in the Hermit Hill Complex. None of these springs contains the typical mound spring invertebrates. Exploitation of the water from the Great Ar- tesian Basin has resulted in a drop of the po- tentiometric surface by several tens of metres in heavily developed areas (Habermehl, 1980). Even by the turn of the century the sinking of bores near some springs had greatly reduced or extinguished their flow (Pittman & David, 1903). At present, a new steady-state condition appears to have been reached in which total recharge and discharge are approaching equilibrium again (Habermehl & Seidel, 1979; Habermehl, 1980), and little change is ex- pected to occur in the discharge rates of the springs provided no new well development takes place. Spring groups and complexes: The mound springs in the Lake Eyre Supergroup are not distributed evenly and for the purposes of this report can be divided into several major spring complexes. Within each of these com- plexes spring groups can be identified. A spring complex can be defined as a large cluster of springs separated from adjacent spring clusters by several tens of kilometres. Smaller groups of springs, either within a complex or an isolated group, can be referred to as spring groups. For example, Hawker Springs can be called a spring group within the Mt. Margaret Spring Complex. In the Her- mit Hill Spring Complex there are several spring groups, e.g., Finniss Swamp West (= West Finniss), Hermit Hill Springs Proper and Old Woman Springs. The following classifica- tion of spring complexes in the Lake Eyre Su- pergroup is essentially that proposed by Kin- hill-Stearns (1984) (Fig. 2). Table 1 lists the springs, grouped in complexes, containing hydrobiids. To facilitate discussion we have arranged these spring complexes into seven informal systems (Fig. 2), the arrangement being bi- ased towards the distribution of the hydrobiid fauna. Detailed maps for each spring area are given in Appendix 1 and these are referred to in the list below. 1. The Oodnadatta Springs. Mt. Dutton Spring Complex. The few small springs on the Oodnadatta Map Sheet that lie southeast of Oodnadatta (Appendix 1, Fig. 63). 2. The Freeling Springs: The Peake Hill Spring Complex. Includes the Freeling Springs and a few small springs to the north and northwest of Mt. Denison (Ap- pendix 1, Figs. 58, 63B). 3. The Northern Springs: Mount Margaret Spring Complex. Includes the large, scattered group of springs to the east of Mt. Margaret, as well as the Peake and Denison Ranges (Appendix 1, Fig. 59). 4. The North Western Springs: a) Nilpinna Spring Complex. A few scattered, small, springs to the west of the Marree- Oodnadatta Road and west of the Mt. Marg- aret Spring Complex (Appendix 1, Fig. 58). 8 TABLE 1. Distribution of taxa in springs and spring complexes. x PONDER, HERSHLER & JENKINS present (living), s = shells only SPRING OR SPRING GROUP Southern Springs Welcome group Davenport group Е. zeidleri form A Е. zeidleri form В F. aquatica form A F. aquatica form B F. accepta form A x x F. accepta form B F. accepta form C F. variabilis form A F. variabilis form B F. variabilis form C F. billakalina F. conica T. punicea T. smithi T. minuta T. inflata SPRING COMPLEX Wangianna Spring Complex Old Woman group West Finniss group Hermit Springs group Old Finniss group Dead Boy Spring Sulphuric group Bopeechee Spring X XXX xX x no x | x x Hermit Hill Spring Complex Venable Spring Priscilla Spring Centre Island Spring Emerald Spring n DINK KK KK KK VID x KKK KK x | x »x Lake Eyre Spring Complex Middle Springs Horse East group Horse West group Strangways Spring Mt. Hamilton Spring Blanche Cup group (785, 787) Blanche Cup Spring Blanche Cup group (786) Little Bubbler Spring The Bubbler Spring X X X X KK KK x X |x xxx x KKK KK KK x Blanche Cup Spring Complex Coward Springs Railway Bore Coward Springs group Kewson Hill group Julie group Elizabeth group Jersey group x X KK x Coward Spring Complex Warburton group Beresford group South-Western Springs Strangways group Billa Kalina group Fenced Spring Welcome Bore Spring Margaret Spring Francis Swamp group Loyd Bore spring Northern Springs Brinkley Spring — Hawker group Twelve Mile group Outside group Fountain group Big Perry Spring Spring Hill Spring Freeling Springs Freeling group Pn Wer | RR SA MC et RE a LACA x KX DID x x | x N XX XX XxX x DDC III 40° C., number of days/month with temperatures >35° C., number of days/month with temperatures <0° C., and number of days/month with temperatures <2.2° С. b) Lake Cadibarrawirracanna Spring Com- plex. A widely scattered group of springs west of William Creek; the most westerly of all the spring complexes (Fig. 2; Appendix 1, Fig. 58). 5. The South Western Springs: a) Francis Swamp Spring Complex. A large group of springs south of William Creek (Ap- pendix 1, Fig. 60). b) Old Billa Kalina Spring Complex. A scat- tered group of springs south of Francis Swamp on the northern side of Margaret Creek (Appendix 1, Fig. 60). c) Strangways Spring Complex. A compact group of mostly extinct carbonate mounds to the east of Francis Swamp (Appendix 1, Fig. 59). 6. The Middle Springs: a) The Beresford Spring Complex. Two main springs associated with two very large, extinct mounds, North and South Beresford Hills (Ap- pendix 1, Figs. 60, 61). b) Coward Spring Complex (Appendix 1, Fig. 61) includes the springs between Coward Springs and Hamilton Hill. 7. The Southern Springs: a) Lake Eyre Spring Complex. A few springs on the southern and southwestern sides of Lake Eyre South and on islands in this lake (Appendix 1, Figs. 61, 62). b) Hermit Hill Spring Complex. Several large groups of springs in the vicinity of Hermit Hill (Appendix 1, Fig. 62). c) Wangianna Spring Complex. Includes the Welcome and Davenport Spring Groups, as well as the degraded Wangianna Spring (Ap- pendix 1, Figs. 62, 63B). Climate: Basic meteorological data for this region are presented in Fig. 3. Note the fre- quency of summer days with >40° C temper- atures. Annual rainfall at Marree varied from 39.3-379.9 mm for the 21 years between 1957-1982, and at Oodnadatta from 54.3— 465.8 mm for the 20 years between 1958— 1982. Evaporation is exceedingly high, usu- ally >10mm/day (Fig. 3) and, for a given year, typically exceeds precipitation by a factor of 10 or more (data for Oodnadatta and Marree were provided by the Bureau of Meteorology). 10 PONDER, HERSHLER & JENKINS MATERIALS AND METHODS Taxonomy Taxonomic rationale: Because the mound springs are isolated from one another, each population has the potential to contain a unique genome that, given sufficient time, iso- lation and selective pressure, could develop into separate taxa. It was impractical to ana- lyse а! populations but a representative, non- random selection (Appendix 2, Tables 18-21) was made and these populations were treated as separate units in the statistical analyses to prevent bias towards the initial subjective split into species units. The method that we have used to distin- guish taxa is essentially phenetic. The phe- netic grouping of populations by discriminate analysis is used as an aid for recognizing taxa but because strict acceptance of phenetic classifications, we believe, can be mislead- ing, a subjective element was also intro- duced, generally on the side of caution. The rather large number of characters measured were statistically tested for differences be- tween the recognised taxa. Most taxa are dis- tinguished by at least one major set of char- acters (e.g., opercular, shell or reproductive) that are statistically significantly different (p < 0.01) from the phenetically closest taxon. It is yur belief that the classification that we present is conservative and in all probability, by using techniques such as electrophoresis, genetic differences not easily recognised in the phenotype will be detected, and additional subdivision required. An electrophoretic pro- gram is planned that will test the classification adopted here and investigate some of the questions raised in the discussion. Cladistic methods were not applied in this . study because species discrimination de- pended largely on measurements, which would lead to difficulty in adequately defining character states. Thorpe (1976) has discussed the practical and theoretical problems involved with sam- pling and analysing the phenetic differences among populations. He points out that there are two aspects to the problem of sampling, obtaining enough specimens to take account of local variation and surveying enough local- ities to represent the geographical area under consideration. We believe that our samples come close to meeting these requirements, especially as far as the shell and opercular data are concerned. Certainly the amount of variance obtained in most characters within even the wider-ranging taxa is generally small. There are some inherent problems in work- ing with hydrobiids because their shells are simple, unicoloured, rather featureless and small. Measurements of a number of shell pa- rameters provide a picture of the shell that can be statistically analysed to detect subtle differences that occur between taxa. The opercular characters of species of Fonscoch- lea have proved to be useful. The number and relative development of the pegs on the inner surface of the operculum are the most useful opercular characters. These pegs are appar- ently a mechanism to increase the surface area for the attachment of the columellar muscles. The anatomical characters were much more difficult and time-consuming to study and, consequently, smaller numbers of individuals were examined. Important and ob- vious anatomical differences occur between the species of Trochidrobia, but within the two primary groups of Fonscochlea the anatomi- cal differences are small and show high vari- ance. Non-quantified characters, such as the pigmentation patterns on the head, were con- sidered when constructing our classification, although in some taxa head-foot pigmentation showed considerable intra- and inter-popula- tion variation. Ratios were calculated using a number of measurements in all three data sets of shell, operculum, anatomy, in an at- tempt to reduce size-dependent differences and generate shape variables. These were used in the initial screening of the data to as- sist with the delineation of taxa. Species are recognized in those cases in which, first, there were one or more morpho- logical differences, which we judge to be sig- nificant, between the individuals in one taxon compared with the most similar taxon, and/or second, the taxa, recognisable by one or more differences, are sympatric and conge- neric. Sympatric in this sense is used to in- clude taxa living not only within the same spring but in closely associated springs (within a few hundred metres) in the same spring group (i.e. parapatry). Subspecies have not been recognised but geographic forms have been identified where, within a taxon recognised as a species, there are one or more differences judged to be of significance between allopatric populations, i.e. from different spring groups. These forms are apparently of infraspecific status but whether they should be formally named must AUSTRALIAN SPRING HYDROBIIDS 11 await an analysis using biochemical methods. Nevertheless we have set out a formal diag- nosis and description of each of these forms so that future investigation can more readily focus on some of the more important geo- graphic differences that occur in the species that we recognise. In each case in which more than one form is recognised, form A is the typical form. Materials: Specimens were collected by sifting sediment with a plastic hand sieve hav- ing a mesh size of approximately 1 mm, and by washing vegetation and solid objects (stones, bones, wood) into a bowl. Sieve con- tents were tipped into a bowl and excess wa- ter drained out. Snails and crustaceans usu- ally sank to the bottom of the bowl and were collected in bulk. Although care was taken, some of the crustaceans, but very few mol- luscs, were lost during this process by their floating out with the excess water. The mate- rial was preserved in 5-10% formalin neutral- ised with excess NaHCO;, after relaxation with menthol crystals for 10-12 hours. For most springs, separate collections were taken at the head of the spring, at the upper part of the outflow, and at the middle part of the outflow. Collections were also often taken at the lower outflow and elsewhere, depend- ing on the type and size of spring and amount of time available. Separate samples were sometimes taken from the water edge and middle of the flow, otherwise the sampling combined these zones. Before sorting, samples were sieved in the laboratory through a 1 mm mesh to minimize any size bias produced by use of hand sieves during collecting. Samples were sorted under a low-power binocular microscope. If the sample was especially large, it was subsam- pled by removing all animals from a portion of the sample after thorough mixing, until a max- imum of 600 individuals of any one species had been counted. The specimens were sorted into species and the counts of number of individuals for each species were used to give approximate percentage frequencies. Adults and subadults only were used in the percentage frequency analyses as identifica- tion of juveniles to species was difficult and time-consuming. Empty shells were ignored in counting. The results obtained by the ana- lyses of qualitative samples have several lim- itations that are discussed below. Most of the material on which this report is based is housed in the Australian Museum (AMS). The holotypes, some paratypes and some other representative specimens are in the South Australian Museum, Adelaide (SAM). A representative collection is housed in the United States National Museum of Nat- ural History, Washington, D.C. Methods: Series of 20-25 adult (occasion- ally more) snails were randomly selected from given samples for morphological analyses in the following manner. The sample was placed into a Petri dish, the bottom of which was di- vided into a grid of 50 equal-sized and num- bered squares. A random number table was used to select grid squares. All adult snails, excluding highly eroded specimens, were re- moved from each selected square until the desired number of specimens was obtained. Shells were measured with either a Wild dis- secting microscope (M5 or M7) fitted with an ocular micrometer, or with a Houston Instru- ments Hipad Digitizer linked to a Morrow Mi- crodecision (MD2) computer. For measure- ments using the former method, a shell was first affixed to a piece of plastic clay, apex pointing directly upwards, so that protoconch diameter (PD, Fig. 4c) could be measured and counts made of protoconch and teleoconch whorls (PW, TW). The shell was then reori- ented to the standard position, i.e. aperture facing upwards (Fig. 4a) and measurements made of shell height (SH), shell width (SW), aperture height (AH), aperture width (AW), and length of the body whorl (BW, Fig. 4a). For most shells measured using this method, a Wild M-5 microscope was used with 10 x eye- pieces, and 12x (large species) or 25x (small species) magnification for all shell fea- tures except protoconch diameter (50 x ). The variance in shell measurements using the oc- ular micrometer, as determined by repeated measurements of a given feature on a single specimen, was approximately 0.05 mm. For measurements using the digitizing pad, shells were oriented in the positions de- scribed above and placed under a Wild M-5 dissecting microscope. The shell image was projected onto the digitizing pad by a drawing apparatus attached to the microscope. Shell features were measured by placing the cur- sor, equipped with a cross-hair, over stan- dardized points of the shell in a predeter- mined sequence, with coordinate data sent to the computer at these points by pressing the cursor button, using the point, not stream, mode. In addition to the six meristic variables listed above, the width of the first half-whorl of 12 PONDER, HERSHLER & JENKINS B D OL— ceed b aN Zn FIG. 4. Shell and operculum, showing various measurements. A. Shell. AH, aperture height; AW, aperture width; BW, height of body whorl; SH, shell height; SW, shell width; WB, width of body whorl. B. Shell showing measurements taken for convexity calculation (see methods). C. Protoconch. PD, protoconch diameter. D. Operculum, inner side. OL, opercular length. E. Operculum, side view. PC, length of calcareous area; PH, peg height. F. Pallial cavity, showing selected measurements of pallial structures. A, anus; CA, distance from anus to ctenidium; CG, capsule gland; CO, distance between posterior end of osphradium and posterior end of ctenidium; CT, ctenidium; LC, length of ctenidium; ML, maximal length of pallial cavity; MM, minimal length of pallial cavity; MW, width of pallial cavity; OS, osphradium; R, rectum; RO, renal opening. the body whorl (WB, Fig. 4a) and convexity of the penultimate whorl (CV; see below) were also measured using the Hipad. The Hipad was significantly more accurate than the above method, with repeated measurements varying by less than 0.02 mm. After a shell was measured it was cracked and the snail sexed by examination of the anterior portions of the genital tracts. After sexing, opercula were removed from the same groups of snails used for shell mea- surements. Because measurements taken of the opercula of species of Trochidrobia did not provide useful data, these have been ex- cluded from the analyses. The following methods apply to the opercula of species of Fonscochlea. Opercula were measured using ` а Wild M-5 dissecting microscope equipped with an ocular micrometer, with 10x eye- pieces and 50x magnification. Opercula were first fixed flat onto a piece of plastic clay with the side that was attached to the foot facing upwards. The opercular length was measured (OL, Fig. 4d) and the calcareous pegs were counted. Then the opercula were stood on edge, with the pegs projecting be- neath the operculum (Fig. 4e), enabling the length of the calcareous deposit (PC) and the height of the tallest peg (PH) to be measured. Specimens were dissected after their shells were dissolved in Bouin’s solution. Dissec- tions were done while the animals were pinned out in a black wax-bottomed dish filled with a solution of 50-70% Bouin's solution AUSTRALIAN SPRING HYDROBIIDS 13 and water. Pallial and head structures were measured after the pallial roof and visceral coil were removed from the head/foot/neck. The digestive gland and gonad were then measured, followed by the other reproductive organs and stomach. All measurements were made, in the latter part of the study, with a crossed measuring reticule, divided into 200 segments on each line, in a 25x eyepiece using 31 x magnification on the Wild M-7, or 25x magnification on the Wild M-5. In the early stages of the project a single line reti- cule, divided into 120 segments, in a 10x eyepiece, was used at 31 x magnification on the Wild M-7. All measurements were con- verted into millimeters and used for calcula- tion of ratios by the computer (see below). The mean, standard deviation and variance were calculated for each attribute by sex for each population, using the microcomputer. All data files generated from the microcomputer were reformatted into data matrices based upon species and attribute groups and trans- mitted ма a modem to disk storage on a main- frame computer, initially the CSIRO Cyber computer but more recently the NSW Data Processing Bureau Burroughs 7700. The Sta- tistical Package for the Social Sciences was used to generate descriptive statistics (sub- program BREAKDOWN), test homogeneity of variances with both Bartlett’s and Cochran's C-test, and perform two-tailed, single classifi- cation analyses of variance with the subpro- gram ONEWAY for each attribute. Missing data were ignored. In the cases in which groups of populations displayed significant heterogeneity of variance for given attributes, the data were transformed using either a log or arcsine transformation prior to analysis of variance. Student-Newman-Keuls test (SNK) and the Scheffe test were used to compare means using 0.05 and 0.001 probability lev- els. For all tests, significance was checked using the tables of critical values in Rohlf and Sokal (1969). Tests for sexual dimorphism were carried out using the subprogram ONE- WAY on selected attributes for all species groups at probability levels of 0.05 and 0.001. Because some characters in some species proved to be sexually dimorphic, the male and female data were analysed separately. Multivariate analysis was undertaken using discriminate function analysis (MDA) (here- after referred to as discriminate analysis) us- ing the BIOSTAT package of programs (Pi- mentel & Smith, 1986). Because there are problems in using ratios in multivariate anal- yses (Brookstein et al., 1985) and closely cor- related measurements a reduced set of mea- surements was used in the discriminate analyses [Fonscochlea: shell: SH, SW, AH, TW; operculum (not used with F. zeidleri): OL, PH, PC, PN; Trochidrobia: SH, SW, AH, AW, BW, TW, PD]. Discriminate analyses were run for each species group at the population level with sexes separate, and populations grouped into species and/or geographic forms of spe- cies with sexes separate and sexes combined. Anatomical data sets were run in the same way with two species groups in which ana- tomical data were used primarily to discrimi- nate some of the species and geographic forms (Trochidrobia spp.; female genital mea- surements: GO, CG, AG, BC, WB, DB, CV, DV; “large aquatic” species of Fonscochlea; pallial measurements: LC, WC, FC, AC, HC, LO, WO, DO, CO, with sexes combined be- cause of small numbers for each station). Because of space constraints the univari- ate statistical analyses of the measurement data are not provided, nor are the details of the measurements obtained for every popu- lation. In the case of those data utilized in discriminate analysis, however, the results of an SNK test (P<0.05) are given for each character. It is hoped to utilize further the ex- tensive set of measurement data in conjunc- tion with a planned electrophoretic program. A summary of the measurement data is given in Appendix 2, Tables 18-21. Characters: For descriptions of the taxa and analyses of morphological variation, the characters listed below were quantified for samples of snails from given populations. The characters of the shell that were mea- sured (Fig. 4A-C) are: Maximal diameter of protoconch (PD). Number of protoconch whorls (PW). Number of teleoconch whorls (TW). Shell height (SH), maximal length of shell along shell axis. Shell width (SW), maximal width of shell perpendicular to shell axis. Length of body whorl (BW), length from the suture, at junction of penultimate and body whorls. Width of body whorl (WB), maximal diame- ter of first half-whorl of body whorl. Height of aperture (AH), maximal length parallel to shell axis. Width of aperture (AW), maximal width per- pendicular to shell axis. Convexity (CV), shortest distance from line 14 PONDER, HERSHLER & JENKINS connecting sutures at junction between pen- ultimate and body whorls to most abaxial point on whorl outline (Fig. 4B:c-d), divided by length of line connecting the two sutures (Fig. 4B:a-b). The following ratios were generated from the shell measurements and used in the data analysis: protoconch diameter/shell height (PD/SH); shell width/shell height (SW/SH); aperture height/shell height (AH/SH); aper- ture height/length of body whorl (AH/BW); ар- erture width/width of body whorl (AW/WB); and an estimation of the degree to which the outer lip of the aperture protrudes beyond the outline of the junction of the penultimate and body whorl (WB/SW). The opercular characters determined were: Opercular length (OL), the maximal length of the operculum. Number of opercular whorls (OW); deter- mined for species of Trochidrobia only. Number of pegs (PN) (i.e. number of sep- arate calcareous projections); determined for species of Fonscochlea only, as were the fol- lowing opercular characters. Maximal height of pegs (PH), including thickness of operculum itself. Length of calcareous smear (PC), length of calcareous deposit associated with pegs. Several anatomical characters were deter- mined. All measurements are maximal widths, lengths etc. unless otherwise stated. Characters of the head/foot and general body are: Length of snout (LS), distance from eye to snout tip. Length of tentacles (LT), distance from eye to tentacle tip. Length of buccal mass (BM), measured af- ter removal from snout. Length of radular sac behind buccal mass (RS), length of portion of radular sac protrud- ing from posterior end of buccal mass. Length of digestive gland (LD), measured along its mid-upper surface following the coil. Length of gonad (LG), measured as above. Length of the digestive gland anterior to go- nad (DG). In the case of the pallial cavity all measure- ments were taken with the pallial cavity re- moved and flattened out (Fig. 4F). Characters are: Maximal and minimal lengths of pallial cav- ity (ML, MM), distance from renal opening to given points along edge of cavity (Fig. 4F). Width of pallial cavity (MW), taken as width of cavity approximately perpendicular to rec- tum (large species of Fonscochlea) (Fig. 4F) or as width along mantle edge (small species of Fonscochlea, and Trochidrobia spp.). Number of ctenidial filaments (FC). Length of ctenidium (LC), following curva- ture of ctenidium (Fig. 4F). Width of ctenidium (WC), maximal width along long axis of filaments. Gill apex (AC), width of ctenidium from left side to position of filament apex. Filament height (HC), height of a filament at widest part of ctenidium. Length and width of osphradium (LO, WO). Distance between posterior tip of osphra- dium and posterior tip of ctenidium (CO) (Fig. 4F). Shortest distance between osphradium and edge of pallial cavity (DO). Distance between ctenidium and anus (CA), measured as shortest distance between anterior end of ctenidium and left side of anus (Fig. 4F). Shortest distance between anus and man- tle edge (MA). Characters of the stomach are: Length (SL), taken as entire length of stom- ach, including style sac, for Trochidrobia and small species of Fonscochlea, and length of stomach excluding style sac portion for large species of Fonscochlea. Length of style sac (SS). Height of anterior stomach chamber (AS). Height of posterior stomach chamber (PS). Many characters of the genital system were measured. Whereas small variations due to reproduc- tive state could not be assessed in this ana- lysis, all individuals for which genital charac- ters were measured appeared to be sexually mature. Immature or parasitized specimens were rejected. Characters of the male genitalia are: Length and width of prostate gland (PR, PW). Length of pallial portion of prostate gland (PP), that part protruding into pallial cavity. Length of penis (PL). Characters of the female genitalia are: Length of glandular oviduct (GO). Length of capsule gland (CG) and albumen gland (AG). Length of genital opening (GP). Length and width of bursa copulatrix (BC, WB). Length of duct of bursa copulatrix (DB). Length and width of “seminal receptacle” (SR, WR), only for Fonscochlea. AUSTRALIAN SPRING HYDROBIIDS 15 Length of duct of “seminal receptacle” (DR), only for Fonscochlea. Length of coiled portion of oviduct (CV), length of coiled section posterior to “seminal receptacle” (Fonscochlea) or bursa copulatrix (Trochidrobia). Maximal and minimal diameters of coiled portion of oviduct (DV, MO). Length of oviduct between seminal recep- tacle and bursa copulatrix (BS); Fonscochlea only. Length of free portion of ventral channel (VC), that portion anterior to duct of bursa copulatrix. For species of Fonscochlea, the following groups of anatomical ratios were used: a) pal- lial ratios: LC/SH (SH is shell height), LO/SH, FC/SH, MM/SH, HC/SH, MA/SH, CA/SH, MW/ MM, LO/LC, HC/WC, AC/WC, WC/LC, WO/ LO; b) general ratios: BM/SH, BM/RS, LT/LS, LD/SH, LG/LD; c) stomach ratios: SS/SL (see comments above under SL), PS/AS; d) male genital ratios: PL/SH, PP/SH, PP/PR; e) fe- male genital ratios: AG/SH, CG/SH, CG/AG, BC/AG, DB/AG, SR/BC, CV/GO, VC/CV, VC/ AG, BS/OD (OD= CV + VC), OV/GO (OV= CV + VC + BS). For Trochidrobia, the pallial ratios, stomach and general ratios, and male genital ratios were precisely the same as those for Fonscochlea, except that shell width (SW), rather than shell height, was used for scaling. The female genital ratios generated for Trochidrobia were AG/SW, CG/SW, CG/ AG, BC/AG, DB/AG, CV/GO, VC/CV, VC/AG, DV/MO, DB/BC, and DV/VC. Anatomy Two species are described in detail, F. ac- cepta (form A), from Welcome Springs, and T. punicea, from Blanche Cup Spring and Fin- niss Springs. Some supplementary informa- tion is given for F. zeidleri from Blanche Cup Spring. The specimens were dissected by the same methods used to obtain the anatomical measurements above). Specimens fixed in Bouin’s solution were sectioned in paraffin at about 6 microns and stained with Mallory’s Triple Stain. Physiology Materials: The following snail species (with localities) were used in the experiments: Troch- idrobia punicea (Finniss Springs), Fonscoch- lea conica (Welcome Springs), Fonscochlea variabilis form A (Blanche Cup, Coward Springs Railway Bore), Fonscochlea accepta form B (Finniss Springs), Fonscochlea ac- cepta form A (Welcome Springs), Fonscoch- lea aquatica form A (Blanche Cup) and cf. form A (Kewson Hill) and Fonscochlea zeid- leri form A (Finniss Springs, Blanche Cup, Kewson Hill and Coward Springs Railway Bore). These species represent the majority of those found in the southern and middle groups of springs found between Marree and Oodnadatta. The springs from which the material studied was collected were, for logistical reasons, all in the southern half of the spring system be- tween Marree and Oodnadatta (see Appendix 1 for detailed maps and station details). These were, in east-west order: Welcome Springs (Stn 756), a moderately large spring with a low mound. A small pool near the head is a few cm deep and there is a shallow (< 1cm), rather long outflow. The substrate is a mixture of calcareous rock, sand and mud. Sedges are moderately com- mon and filamentous algae are abundant. Finniss Springs (Stn 693), a small spring with a very low sand mound. The substrate is sand and mud. Sedges are common and fil- amentous algae are present. Blanche Cup Spring (Stn 739), a conical calcareous mound with a pool at the top (Fig. 1a). The outflow is shallow and mainly broad and flows over calcareous rock but the pool contains mainly mud. Sedges line the pool edges and filamentous algae are abundant in the pool and in the outflow. Coward Springs Railway Bore (Stn 743), a very large swamp issuing from a large pond with the bottom composed mainly of silt. The water depth is generally in excess of several cm where the specimens were collected, in the vicinity of the pond outflow. Large sedges and rushes line the edges of the pool and outflow. Filamentous algae are abundant. This is the only known case in which the mound spring snails have become estab- lished in a bore drain. It is also the only known locality at which F. zeidleri is aquatic as well as amphibious. Fonscochlea aquatica is not found here and T. punicea is uncommon. Kewson Hill Springs (Stn 742), one of sev- eral small springs issuing from this hill. They trickle down the steep hillside in narrow out- flows where they form a series of small ter- races (Ponder, 1986), each containing water a few mm deep. There is no vegetation apart from some filamentous algae. 16 PONDER, HERSHLER & JENKINS Methods: All experiments were conducted in a makeshift laboratory set up in a large tent (5 x 4 m) in the field between August 27 and September 9, 1983. Snails from given popu- lations were collected and then held in water in aerated plastic containers (16 x 16 cm) for one to three days before being used in the experiments. When possible, water from the spring from which a given sample of animals was collected was used for holding both the animals and for the experiments (Blanche Cup, Welcome Spring, Coward Springs Rail- way Bore). In instances in which a large water sample could not be obtained owing to shal- low water and/or low discharge, water from a nearby spring or bore was used. In the case of Finniss Springs, the water was taken from a bore about 7 km southwest of Hermit Hill and the water used for the experiments with F. aquatica from Kewson Hill was taken from the Blanche Cup Spring. Full analyses of the water from these localities is given in Kin- hill-Stearns (1984). A running record of the laboratory environment (air temperature, hu- midity) was kept. To avoid introducing age- related differences, only adult snails, i.e. those possessing a complete and thickened peristome, were used for the experiments. A major problem encountered in physiolog- ical experiments involving shelled gastropods is determining when individuals are dead. Re- traction of the snail into its shell usually oc- curs before death in response to unaccept- able conditions. For most of the experiments the activity of the snails was used as an indi- cator of their tolerance to the conditions being presented. Given the time constraints inher- ent in the project, the customary replicates of each experiment could not be done. We pre- ferred to use the available time to run each experiment for all of the taxa. The detailed methods of each type of experiment are given below. In the desiccation experiments animals from given populations were placed in a se- ries of 9-cm Petri dishes. Ten specimens were placed in each dish. The dishes were of three types: those lined with dry filter paper and without a lid (hereafter referred to as dry); those lined with moist filter paper and with a lid (moist); and those half-filled with water and with a lid (wet). The moist and wet tests served as controls. A total of 21 dishes, seven sets of each of the three types, was set up for each population tested. A separate set of dishes was checked after periods of one, two, four, six, 12, 24, and 48 hours from the be- ginning of the experiment. As the moistened dishes tended to dry out, despite having lids, they were frequently examined and re-moist- ened whenever necessary. To check for sur- vival of snails in a set of dishes, the dishes were first flooded, if dry or moist, with water. The number of animals in each dish that were active 10 minutes after flooding was noted. A similar check for active animals was made one hour after flooding. Animals inactive after one hour were considered dead. Death was confirmed for the snails by tests carried out in some of the early runs: shells were gently crushed to expose the animal, placed under a dissecting microscope, and the mantle was not seen to retract when prodded. In the salinity experiments table salt was added to the appropriate spring water to ob- tain solutions of six, nine, 12, and 24 %o. The salinities of these solutions were tested using an optical refractometer. Each of these solu- tions, as well as anormal sample of the spring water, for which a zero salinity reading was obtained using the refractometer, serving as a control was added to a glass jar of about 380 cc brimfull capacity, which was then capped with a plastic lid to exclude air from the jar as much as possible. Ten specimens were placed into each of these five jars. After inter- vals of one, two, three, six, 12, and 24 hours, each of the jars was examined, but not opened, and the number of active or clinging snails counted. Mortality was not tested. The salinities for each of the water sources used, calculated from the conductivities given by Kinhill-Stearns (1984), are shown in Table 12. In the experiments with deoxygenated wa- ter, water from the appropriate spring was boiled for two to three minutes in a glass bea- _ ker and then poured very gently, to prevent reoxygenation, into each of five 25 cc test tubes. Rubber stoppers were then gently in- serted into each of the tubes. The tubes were cooled and then 20 snails were placed into each of them, as well as into a sixth tube con- taining well-oxygenated spring water as a соп- trol. The tubes were then again firmly stop- pered, with an effort made to exclude air bubbles. After intervals of one, two, four, six, and 20 hours, a tube with deoxygenated water was checked in the following manner. First the number of active specimens in the tube was counted. Then the specimens from the tube were placed into a dish with oxygenated water. The number of active specimens in the dish was counted after periods of ten minutes and one hour. Specimens inactive after one hour AUSTRALIAN SPRING HYDROBIIDS 17 were considered dead. At the end of each of the five time periods, the control tube was ex- amined as well, but not opened, and the num- ber of active individuals in the tube counted. The purpose of the temperature experiment was to determine activity of animals at various temperatures. Twenty specimens were placed into each of two 275 cc jars, half-filled with water. One jar was slowly heated by placing it into a steam-heated, water-filled dish. The jar was periodically removed from the water bath, the temperature of the water in the jar noted, and the number of active in- dividuals in the jar counted when the desired temperatures were reached. The process was continued until such a temperature was reached at which all specimens became inac- tive. A similar method was used to determine tolerance to low temperatures: the second jar was placed into a small freezer and periodi- cally removed to check the temperature and count the active animals. Again, the experi- ment was terminated when all specimens be- came inactive. The jars were not aerated dur- ing the experiments. Mortality was not tested and no attempt to achieve acclimation was made. In determinations of submergence toler- ance a 380 cc jar was filled to the brim with water and 20 snails were added. The jar was then capped with a lid that had a small hole in it so that an aerator tube could pass through it into the jar. An aerator stone was attached to the end of the tube. At intervals of one, two, four, 15, 24, 48, and 72 hours, the jar was examined and the number of active snails counted. In experiments of submergence/ non-submergence preference a plastic plate was used (diameter of 220 mm), with a flat circular bottom (diameter of 150 mm), steeply- sloping sides (approximately 60° width of 13 mm), and a slightly-sloping rim (approxi- mately 10° width of 22 mm). The dish was filled with water to the lower edge of the rim. Fifty snails were placed in the dish and left forthree hours. At the end of this time period the num- bers of specimens found on the bottom of the dish, on the steep slope and on the broad rim (out of the water) were counted. In determinations of response to light a 200 x 200 x 15mm clear perspex box, with tightly-fitting lid, was constructed for use in this experiment. Three lines were drawn across the width of the box in order to divide the box lengthwise into four equal zones. One hundred snails were placed in the box to- gether with water. The water level in the box was then topped off and the lid placed on top, with a smear of petroleum jelly added to the sides to provide a seal. Care was taken to exclude any air bubbles from the box. Half of the box, containing two entire zones, was covered with a dark plastic sheet and then an Olympus dissecting microscope lamp was placed 2 cm above the mid-line at the uncov- ered end of the box. The lamp was oriented so that its beam was perpendicular to the plane of the box. The lamp was then turned on, to level 6 on the transformer, and the en- tire apparatus, box and lamp, was covered with a black plastic sheet to exclude other light. After one hour both the dark sheet and the sheet covering one half of the box were removed, and the numbers of animals in each of the four zones were quickly counted. The numbers of snails found in the light and light- middle zones were combined, as were those found in the dark and dark-middle zones, in order to obtain sufficiently high frequencies for the statistical analysis of these results. For most of the populations tested, two separate runs were done. The box was thoroughly washed and all grease removed between runs of this experiment. To test for differences in results between runs, populations or species, the following statistical tests were used (following Siegel, 1956): Fisher’s Exact Test, when the experi- ments involved fewer than 20 animals or when expected frequencies in cells were fewer than five; and The Chi-Square Test of Independence, with continuity correction, when the experiments involved 20 or more animals with expected frequencies in the cells exceeding five. Null hypotheses were re- jected when the significance level was less than or equal to 0.05. RESULTS Taxonomy The hydrobiids occurring in the Lake Eyre Supergroup are formally described in this section. Two new genera, Fonscochlea with six species and Trochidrobia with four spe- cies, are erected, with a new subgenus, Wolf- gangia, of Fonscochlea, containing one spe- cies. Geographic forms are recognised in four of the species of Fonscochlea, these being formally described but not named. A summary of measurement details is given in Appendix 2, Tables 18-21. 18 PONDER, HERSHLER & JENKINS TABLE 2. Tests for sexual dimorphism in shell height (SH) and shell width (SW). The asterisk indicates a significant difference, at the level indicated, between males and females for all pooled measurements for the taxon. SH SW Species 05 .001 .05 .001 . accepta form A * * * * . accepta form В * * . * . accepta form С адиайса form A адиайса form В . variabilis form А . Variabilis form В . variabilis form C . billakalina conica x * F. zeidleri form A F. zeidleri form B * - T. punicea B * x * T. smithi T. minuta * + T. inflata + + A * * Hua ees > aaa ae але, ххх + Туре species: Fonscochlea accepta п.зр. Distribution: Artesian springs between Mar- ree and Oodnadatta, northern South Austra- lia. Diagnosis: Shells (Figs. 5-7, 14, 19, 22, 23, 25) of known species small to large for family (1.3 mm long), non-umbilicate, ovate- conic to ovate, smooth or with weak axial rugae formed from enlarged growthlines. Pro- toconch (Fig. 9) of about one and one-half whorls, minutely pitted, the pits sometimes ar- ranged into spiral rows (subgenus Wolfgan- gia). Aperture rather large relative to shell length (AH/SH >0.4), oval, thickened when mature, without external varix; outer lip slightly prosocline to slightly opisthocline. Peri- ostracum thin, sometimes developing weak ridges that coincide with the growthlines and, sometimes, spiral scratches. Operculum (Fig. 8) corneous, oval, flat, of few whorls, nucleus eccentric, inner surface with small calcareous smear and/or calcare- ous pegs. FIG. 5. Shells of Fonscochlea accepta. a. Fonscochlea accepta form A, holotype. Welcome Springs (003). b. Fonscochlea accepta form B. Old Finniss Springs (694) (SAM, D. 17918). с. Fonscochlea accepta form С. Emerald Springs (703) (ЗАМ, D. 17919). Those species shown to be sexually dimor- phic in size (at P<0.01) are listed in Table 2. Because most of the species showed evi- dence of dimorphism the morphometric data for each sex were treated separately. Some additional data are provided below. Family Hydrobiidae GENUS FONSCOCHLEA n. gen. Derivation: Fons (Latin), a spring; cochlea (Latin), a snail (fem.). Radula (Fig. 10) with rectangular central teeth, cusp formula 2222, lateral teeth 2-4+1+2-4.Inner marginal teeth with 8-15 cusps, outer marginal teeth with 17-25 cusps. Head-foot (Figs. 11, 24a—9,i) typical of fam- ily. Cephalic tentacles slightly tapering to par- allel-sided; weakly and inconspicuously cili- ated on ventral surfaces. Snout well developed, slightly shorter to slightly longer than tentacles. Pigmentation heavy to light, AUSTRALIAN SPRING HYDROBIIDS FIG. 6. Shells of species of Fonscochlea. a-d,i. Fonscochlea accepta form В. a. Finniss Swamp West (690)(AMS, 0.152978). b. Sulphuric Springs (735) (AMS, С.152979). с. Hermit Hill Springs (711) (AMS, C.152980). d. Old Woman Spring (733) (AMS, C.152981). i. Old Finniss Springs (710) (AMS, C.152982). e-h. Fonscochlea zeidleri form A. e. Elizabeth Springs (024) (AMS, C.152975). f-h. Blanche Cup Spring (008) (AMS, C.152977). pigment granules black and white. No acces- sory tentacles. Pallial cavity (Fig. 4F) with well-developed ctenidium, osphradium oval, about three to four times as long as broad; its posterior ex- tremity situated near posterior end of ctenid- ium. Ctenidium about 3-4.5 times length of osphradium. Alimentary canal typical of family. Stomach (Figs. 43a, 44b, 45) with anterior and poste- rior chambers, single digestive gland opening and no caecal appendage. 20 PONDER, HERSHLER & JENKINS FIG. 7. Shells of species of Fonscochlea. a. Fonscochlea zeidleri form A, Strangways Springs (030) (AMS, C.152992). b. Fonscochlea zeidleri form В, Big Cadnaowie Spring (661) (AMS, 0.152993). c. Fonscochlea aquatica cf. form A, very squat variety, Kewson Hill Springs (742) (AMS, C.152994). d. Fonscochlea billakalina, paratype, Old Billa Kalina Spring (026) (AMS, C.152995). e. Fonscochlea variabilis form В, The Fountain Spring (032) (AMS, 0.152996). f. Fonscochlea aquatica form В, Freeling Springs (665) (AMS, C.152997). g. Fonscochlea accepta form A, Welcome Springs (003) (AMS, C.152998). h. Fonscochlea accepta form B. Old Finniss Springs (694B) (AMS, C.152999). i. Fonscochlea accepta form C, Emerald Springs (703) (AMS, C.153000). Scale: 0.5mm. AUSTRALIAN SPRING HYDROBIIDS FIG. 8. Opercula of species of Fonscochlea. a. Fonscochlea zeidleri form В, Big Cadnaowie Spring (661). b. Fonscochlea zeidleri form A, Coward Springs Railway Bore (018). c. Fonscochlea aquatica cf. form A, Kewson Hill Springs (742). d. Fonscochlea billakalina, Old Billa Kalina Spring (026). e. Fonscochlea variabilis form B, The Fountain Spring (032). f. Fonscochlea aquatica form В, Freeling Springs (665). g. Fonscochlea accepta form B, Old Finniss Springs (694B). hi. Fonscochlea accepta form A, Welcome Springs (003). Scale: 0.1тт. 21 22 PONDER, HERSHLER & JENKINS FIG. 9. Protoconchs of species of Fonscochlea. a. Fonscochlea accepta form A, Welcome Springs (003). b. Fonscochlea accepta form C, Emerald Springs (703). c-d. Fonscochlea zeidleri form A, Strangways Springs (030). e. Fonscochlea aquatica form A, Outside Springs (039). f. Fonscochlea conica, Welcome Springs (003). Scale: d = 0.01mm; all others = 0.1mm. AUSTRALIAN SPRING HYDROBIIDS 23 FIG. 10. Radulae of Fonscochlea. a. Fonscochlea zeidleri form В, Big Cadnaowie Spring (661). b. Fonscochlea zeidleri form A, Coward Springs Railway Bore (018). с. Fonscochlea accepta form В, Old Finniss Springs (694B). d. Fonscochlea accepta form C, Emerald Springs (703). e. Fonscochlea variabilis form В, The Fountain Spring (032). f. Fonscochlea aquatica form B, Freeling Springs (665). Scale: 0.01mm. Female reproductive system (Figs. 12, 27, 47) with two sperm sacs, i.e. anterior bursa copulatrix and posterior “seminal receptacle”, and coiled oviduct Iying on inner (left) side of albumen gland, sperm sacs and major Ovi- duct folds being opposite posterior part of gland or partly extending behind it. Coiled ovi- duct an unpigmented, coiled or undulating 24 PONDER, HERSHLER & JENKINS e FIG. 11. Dorsal views of heads of large species of Fonscochlea; all from living material. a. Fonscochlea zeidleri form A, Kewson Hill Springs. b. Fonscochlea zeidleri form A, Welcome Springs. c. Fonscochlea aquatica form A, Blanche Cup Spring. d. Fonscochlea accepta form A, Welcome Springs. e. Fonscochlea aquatica cf. form A, Kewson Hill Springs. f. Fonscochlea accepta form B, Old Finniss Springs. Scale: 0.25mm. AUSTRALIAN SPRING HYDROBIIDS 25 mcp bc 9 FIG. 12. Female genitalia of species of Fonscochlea. a. Fonscochlea zeidleri form В, Big Cadnaowie Spring. b. Fonscochlea zeidleri form A, Old Finniss Spring. c. Fonscochlea aquatica form A, Blanche Cup Spring. d. Fonscochlea accepta form A, Welcome Springs. e. Fonscochlea accepta form C, Emerald Springs. f. Fonscochlea accepta form B, Old Finniss Springs. g,h. Fonscochlea accepta form A, Davenport Springs; detail of sperm sacs and their ducts shown in В. ag, albumen gland; bc, bursa copulatrix; cg, capsule gland; cv, coiled oviduct; go, oviduct opening; mcp, posterior limit of pallial cavity; sr, seminal receptacle; vc, ventral channel; vcp, posterior extension of ventral channel. Scale: 0.25mm. muscular tube extending from immediately loop posteriorly around sperm sacs at, behind posterior pallial wall, where its initial or just behind, albumen gland. Gonopericar- section forms U-shaped, glandular loop, to dial duct represented by tissue strands only. 26 PONDER, HERSHLER & JENKINS Oviduct between sperm sacs very short to moderately long, forming U-shaped loop. Anterior to bursal duct, which opens to ovid- uct opposite posterior part of albumen gland, muscular oviduct either runs straight to ven- tral channel or thrown into loop. Bursa copulatrix and “seminal receptacle” approxi- mately equal in size and with ducts markedly shorter than length of sacs. Both sperm sacs similar histologically and rather thick-walled. Capsule gland approximately equal in size to albumen gland or slightly smaller or larger. Ventral channel well defined, with conspicu- ous ciliated lateral fold. Genital opening sub- terminal. Male reproductive system with vas deferens complexly coiled beneath anterior part of tes- tis. Pallial and visceral vas deferens enter and leave prostate gland in middle section. Pros- tate gland extends into pallial wall, as slight bulge in some species to about half its length in others. Pallial vas deferens narrow, tubular, and lying beneath epithelium of right side of pallial floor, undulating as it passes across neck and enters base of penis. Penis (Fig. 46) with swollen, unpigmented base bearing prominent concentric creases; distal two thirds smooth and tapering to point, often pigmented and muscular. Penial duct similar to pallial vas deferens, i.e. very narrow, ciliated and with only very thin muscle layer; straight in distal part of penis, undulating in proximal part. Pe- nial pore simple. Egg capsules hemispherical, attached to substrate. Nervous system (Fig. 43b) with typical hy- drobiid pattern: cerebral ganglia separated by short commissure, left pleural ganglion at- tached to suboesophogeal ganglion and right pleural ganglion separated from supra- oesophageal ganglion by long connective. See anatomical section below for further details of anatomy. Remarks: The distinctive features of this genus include the equal-sized sperm sacs, the short ducts connecting these sacs to the oviduct and the position at which they enter the oviduct. In most hydrobiids the bursal duct opens to the oviduct opposite the anterior end of the albumen gland, not the posterior end as in Fonscochlea. The pegged operculum, and the shell of some of the smaller species, re- semble states seen in the Australian species of Hemistomia sensu lato (Ponder, 1982). This genus, and the related genus Tatea T. Woods, 1879, can be distinguished from Fons- cochlea in having a more “typical” hydrobiid reproductive system (Ponder, 1982). In these genera the seminal receptacle is thin-walled and much smaller than the bursa copulatrix, and the bursal duct opens to the oviduct in the region near the anterior end of the albumen gland. In most other respects these three genera are similar. Subgenus Fonscochlea s.s. Diagnosis: Shell (Figs. 5, 6a-d, 1, 7c-i, 14b, d, 19, 22, 23, 25) thin to moderately thick, aperture with thin to slightly thickened peris- tome. Protoconch microsculpture (Fig. 9a,b,e,f) of irregular, shallow pits. Operculum (Fig. 8c-i) with prominent pegs, weak pegs or pegs absent. Radula (Fig. 10c-f) as for genus. (Table 3) Head-foot (Figs. 11c-f, 202-9, i) with ce- phalic tentacles slightly longer than snout. Female genital system (Figs. 12c-h, 27) as for genus except that the oviduct between the ventral channel and the bursal duct is always bent or folded and the sperm sacs lie behind (to the right of) the coiled oviduct and their ducts emerge from their dorsal sides. Male system as for genus. Remarks: The typical subgenus includes five of the six known taxa of Fonscochlea. It encompasses two radiations, one of small species and the other of large species, all of which are aquatic. Group 1: the large aquatic species. Fonscochlea accepta n.sp. Derivation: accepta (Latin), welcome, a ref- erence to the type locality. Diagnosis: Shell about 2.4 to 3.8 mm long, with about 2.5-3.6 convex (convexity ratio 0.08—0.25) teleoconch whorls. Aperture with thin peristome, outer lip slightly prosocline. In- ner lip narrow, loosely attached to parietal wall. Operculum with strong pegs. Shell (Figs. 5, 6a—d,i, 79—1; 9a,b), see diag- nosis. Colour dark brown. Operculum (Fig. 8g,i) with several, usually 3-4, strong pegs. Radula (Fig. 10c,d) as for genus (see Table 3 for details). Head-foot (Fig. 11d,f), see under descrip- tions of the forms of this species below. Anatomy typical of subgenus. Described in more detail in the anatomical section below. The typical form of this species is described AUSTRALIAN SPRING HYDROBIIDS 27 TABLE 3. Cusp counts from radular teeth of species of Fonscochlea and Trochidrobia. Missing counts from the outer marginal teeth are the result of not being able to make accurate counts from the available preparations. mm PPP XX s Central tooth Lateral tooth Inner Outer Noor аа No. ot INS er marginal tooth marginal tooth lateral basal inner outer No. of No. of Species cusps cusps cusps cusps cusps cusps F. accepta form A 3-4 1 3-4 3-4 9-10 24-25 F. accepta form B 3 1-2 2-3 3-4 9-12 — F. accepta form C 4 1-2 3 3-4 10-13 — Е. адиайса form А 3—4 1 2-3 2-4 7-10 — Е. aquatica form В 2-3 1 3 3 8-9 21-25 F. variabilis form A 4-6 1-2 2-3 2-4 12-15 — Е. variabilis form В 3—4 1-2 2-3 2-3 9-12 — Е. variabilis form С 2-4 1-2 2 2-3 9-11 — F. billakalina 3-4 1-2 2-3 2-4 10-12 — F. conica 4-6 1-2 3 3-4 14-18 — Е. zeidleri form А 2-3 2 2-3 3 9-13 17-21 F. zeidleri form B 2-3 2 2-3 3 9-10 20-21 T. punicea 5-8 152 3-6 4-6 24-31 — T. smithi 6-7 1 4-5 5-6 23-25 — T. minuta 4-7 1-2 4-6 6-7 22-24 — T. inflata 6-8 1 5-6 5-7 18-23 — below as “form A” where a holotype is des- ignated for the species. Localities: Southern Springs: Welcome, Davenport, Hermit Hill and Emerald Springs (39. 13). Remarks: Three geographically separated forms are recognised. Discriminate analysis did not convincingly separate two of these us- ing shell and opercular characters but reason- able discrimination was achieved using pallial data. The forms are primarily distinguished by differences in their ctenidia and unquantified differences, including tentacle shape and pig- mentation and habitat preference. This species has a range of about 80 km with the typical form occupying about a 25 km range, separated from the Hermit Hill popula- tions (form В) by about 12 km and those in turn separated from Emerald Spring, the lo- cality of the third form, by about 40 km. This species is the “large aquatic” species of the Southern Springs. It is generally abun- dant in the pool at the head of the springs and in their outflows. It can sometimes be seen clustering on the sides of the outflows but it is not amphibious and, if emergent, is covered by a film of water. Fonscochlea accepta form A. (Figs. 5a, 7g, shell; 9a, protoconch; 8hii, operculum; 11d, head-foot; 43a, 44b, stomach; 43b, nervous system; 46a, penis; 12d,g,h, fe- male genitalia. Diagnosis: Tends to have longer and more numerous ctenidial filaments (Table 18B) than F. accepta form B and shorter filaments than F. accepta form C. Radular sac longer, and ratio of buccal mass to radular sac (BM/ RS) smaller, than in both other forms. Also differs from F. accepta form B in pigmentation and morphology of cephalic tentacles. Shell (Figs. 5a, 7g; 9b, protoconch) as for species, but not so broad relative to length as F. accepta form C. See Table 18A for mea- surement data. Operculum (Fig. 8h) as for species. See Ta- ble 18A for measurement data. Radula as for species. See Table 3 for data. Head-foot (Fig. 11d) black on sides of foot and on neck and snout. Tentacles parallel- sided or taper slightly distally and lightly to darkly pigmented, except for pale median stripe most obvious in individuals with darker tentacles. An indistinct red-brown patch on outer dorsal side of tentacles just in front of eyes present and few dense white pigment cells lie above eyes. Anatomy (Figs. 12d,g,h, female genitalia; 43a, 44b, stomach; 43b, nervous system; 46a, penis) as for species. See Tables 18B-E for measurement data. Type material: holotype (Fig. 5a) (SAM, D.17917, stn 003); and paratypes (003, AMS, ‘воцепЬе ‘+ ‘ваэээе eaJy909suoy ‘saioads oyenbe a61e jo иоцпащ$!А EL ‘Sls =D (HLNOS)” о 3443 JAVI m INH ЕЕ N g WIOJ- (ATUO STTEUS) Y WIOJ- Y wIoJ- eotyenbe ‘4 D шлоз- (ATUO STISUS) я WIOJ- я wIOJ- Y wIoJ- (HLYON) exdeooe ‘4 PONDER, HERSHLER & JENKINS 3443 AVI 000 0001 :1 91095 AAA Eugen о бо 28 AUSTRALIAN SPRING HYDROBIIDS 29 C.152848, many, C.152998, 1, figured; 756A, AMS, С.152849, many; 756B, AMS, C.152850, many; 756C, AMS, C.152851, many). Dimensions of holotype: length 3.26 mm, width 1.83 mm, length of aperture 1.43 mm. Localities: Welcome Springs (002, 003, 754A-D, 755A-D, 756A-C); Davenport Springs (004, 005, 752A,C, 753A,B (Fig. 13). Remarks: The populations at Welcome and Davenport Springs do not seem to show any significant differences in any of the non-gen- ital characters measured but there are some differences in measurements in the female genitalia. In particular BS/OD, CV/GO and OV/ GO are significantly different. It is possible, on more detailed analysis, that these popula- tions, which are more than 20 km apart, will be shown to be separable. Fonscochlea accepta form B. Figs. 5b, 6a—d,i, 7h, shell; 11+, head-foot; 12f, female genitalia; 8g, operculum; 10c, radula Diagnosis: Ctenidial filaments fewer and shorter than in other two forms, and ctenidium tends to be shorter, although these differ- ences not consistently significantly different for all populations. Radular sac shorter, and ratio of buccal mass to radular sac (BM/RS) larger, than in both other forms of F. accepta. Cephalic tentacles with reduced or absent median stripe and not tapered. Shell (Figs. 5b, 6a—d,i, 7h) generally similar to form A but some individuals approach F. accepta form C in shape. See Table 18A for measurement data. Operculum (Fig. 8g) as for species. See Ta- ble 18A for measurement data. Radula (Fig. 10c) as for species. See Table 3 for data. Head-foot (Fig. 11f) similar to that of F. ac- cepta form A but median stripe on tentacles reduced or absent and tentacles usually slightly swollen distally, or if not, parallel- sided (i.e. not tapered). Anatomy (Fig. 12f) as for species. See Ta- bles 18B-E for measurement data. Voucher material: primary voucher speci- men (Fig. 5b) (SAM, 0.17918, stn 694B); ad- ditional material from same station (694B, AMS, C.152852, many, C.152999, 1, figured; 693A, AMS, C.152853, 36; 693B, AMS, C.152854, 50; 693C, AMS, C.152855, 10; 694A, AMS, C.152856, 10; 694C, AMS, С.152857, 16). Dimensions of primary voucher specimen: length 3.17 mm, width 1.86 mm, length of ap- erture 1.38 mm. Localities: Hermit Hill Complex: Hermit Hill Springs (711A-D, 712); Old Finniss Springs (693A-C, 694A-C, 710); Old Woman Springs (733A-E); Finniss Swamp West (690A-C, 691A-D, 730); Dead Boy Spring (689); Sul- phuric Springs (735); Bopeechee Springs (692A,B). Shells, possibly referable to this form, are known from Priscilla (686) and Ven- able (687) Springs (Fig. 13). Remarks: This form is distinguished from F. accepta form A in ctenidal characters, a shorter radular sac, and tentacle shape. The smaller gill seen in F. accepta form B might have evolved in response to the generally small springs found in the Hermit Hill area. This form also differs behaviourly from form A, preferring the shallow water in the outflows to the deeper water in pools, whereas F. accepta form A is found in pools in large numbers. Using discriminate analysis on a subset of shell measurements and opercular measure- ments, populations of this form did not sepa- rate well from F. accepta form A, although partial separation is achieved (Figs. 15, 16; Table 4). Pallial measurements, however, produced a clear separation from form A and the next form (Figs. 17, 18; Table 4). Fonscochlea accepta form C. (Figs. 5c, 7i, shell; 9b, protoconch; 10d, rad- ula; Fig. 12e, female genitalia) Diagnosis: Shell with relatively shorter spire than many other populations, but this not con- sistent. Gill filaments longer, typically twice as long, and more numerous than those of F. accepta form B. Similar, but less pronounced, differences between this form and F. accepta form A, with ratios of ctenidial length/shell length (LC/SH) and length of ctenidial fila- ments to shell length (HC/SH) larger than in both other forms. Distance between anus and ctenidium (CA) and ratio of this distance over shell length (CA/SH) larger than in other two forms. Radular sac intermediate in length be- tween other two forms. Head-foot (not ob- served in living material) similar to F. accepta form A in having well-developed, unpig- mented dorsal stripe on tentacles. Shell (Figs. 5c, 7i; 9b, protoconch) as for species except for a relatively larger aperture (mean of AH 1.52, males; 1.51, females; com- pared with 1.31-1.46 mm for the other two forms). AH/BW is larger in most individuals than in the other two forms (mean 0.62, com- 30 PONDER, HERSHLER & JENKINS TABLE 4. Summary of results of discriminate analysis of the forms of the large aquatic species of Fonscochlea. The numbers are the Euclidean (taxonomic) distances between the groups. FacA FacB F.ac.C F.ag.A F.aq.A(r) F. accepta form A x 0.460 0.598 0.470 0.131 Е. accepta form В 0.459 x 0.503 0.198 0.442 F. accepta form C 0'375 10:370 x 2.722 2.889 F. aquatica form A 1.550 1.667 1.326 (combined) — — — Е. адиайса form А 15384, 1.630 1.272 (restricted) 9.365 9.533 6.756 Е. aquatica cf. form А 2.606 2.463 2.261 0.396 0.539 2.402 Е. адиайса form В 102501253090 3.630 3.797 1.169 Left top—shell + operculum combined sexes Left bottom—pallial combined sexes pared with 0.57-0.58). See Table 18A for measurement data. Operculum as for species. See Table 18A for measurement data. Radula (Fig. 10d) as for species. See Table 3 for data. Head-foot similar to that of F. accepta form A as far as can be judged from preserved material. Anatomy (Fig. 12e, female genitalia) as for species. See Tables 16B-E for measurement data. Voucher material: primary voucher speci- men (Fig. 5c) (SAM, D.17919, stn 703A); ad- F.aq.cf.A F.aq.B Right side: 1.611 1.477 2.519 1.010 Female, shell & operculum 1.472 1.274 2.693 1.042 Male, shell & operculum 1.762 1.742 2.418 1.302 1.570 1.521 2.517 1.229 1.286 1.328 1.964 0.950 1.484 1.298 2.685 1.063 x — — 0.771 = — 0.521 — x 1.842 0.507 — 2.119 0.372 — 1.972 x 2.029 — — 2.020 0.637 0.420 2.004 x — 573% 3.271 ditional material from same station (703A, | AMS, C.152858, many, C.153000, 1, figured; 703B, AMS, C.152859, 60). Dimensions of primary voucher specimen: length 3.10 mm, width 1.90 mm, length of ap- erture 1.40 mm. Locality: Emerald Springs (703A,B). Remarks: This population is recognised as a separate form because it differs from the other two forms, particularly F. accepta form B, in gill characters, as described above. It appears to have head-foot characters similar to those of F. accepta form A, but differs from F. accepta form B in this respect, and also differs in the distance of the anus from the mantle edge from both of the other forms. Dis- criminate analysis on pallial measurement data readily separates this form (Figs. 17, 18; Table 4). This form lives in the upper outflow of a large, isolated spring in swiftly flowing water that reaches a depth of as much as several centimeters. It is common in the roots of dense vegetation around the fenced spring head at the uppermost part of the outflow but relatively rare on the downstream side of the fence where it appears to require shelter beneath debris such as wood. This suggests that, un- like the other two forms, which are commonly seen in the open, this form is strongly pho- tonegative. Emerald Springs is unusual in containing only one species of hydrobiid. This locality is widely separated, by about 40 km, from other populations of F. accepta, the nearest being those in the vicinity of Hermit Hill (F. accepta form B). Fonscochlea aquatica n.sp. Derivation: a reference to the aquatic habit of this species, in contrast to F. zeidleri. Diagnosis: Shell large for genus (2.6 to 4.8 тт long), with 2.1-3.7 teleoconch whorls. Aperture with thin peristome and or- thocline to opisthocline outer lip. Inner lip broad and firmly attached to parietal wall. Operculum with weak or absent pegs. AUSTRALIAN SPRING HYDROBIIDS 31 Shell (Figs. 7c,f; 146,4; 53c,e; 9e, proto- conch) as for diagnosis. Colour yellowish- brown to chocolate or reddish-brown. Operculum (Fig. 8c,f) with pegs weak to moderately strong, or absent altogether. Radula (Fig. 10f) as for genus. See Table 3 for details. Head-foot (Figs. 11c,e) with pale, tapering cephalic tentacles and the darkly-pigmented head and snout. Anatomy (Fig. 12c, female genitalia) typical of subgenus. Similar to F. accepta, differ- ences being mainly size-related. The typical form of this species is described below as “form A” where a holotype is des- ignated for the species. Localities: Middle, South Western, North- ern and Freeling Springs (Fig. 13). Remarks: This species can be divided into two geographic forms, possibly subspecies, which are separated on shell and opercular characters. It differs from F. accepta in its larger size (SH) and most other shell mea- surements are significantly different in nearly all populations and, consequently, many other size-related characters. They also differ in apertural details and in the relatively weaker to absent pegs on the operculum; PH/ OL, PC/OL and PN/OL are all significantly dif- ferent in most populations. The ratio AH/BW (aperture height/body whorl) is significantly larger in F. aquatica than in F. accepta in nearly all populations. This species separated well from F. accepta in discriminate analysis using shell and opercular measurements (Figs. 15, 16; Table 4). Fonscochlea aquatica form A. (Figs. 7c, 14d, 53c,e, shell; 9e, protoconch; 8c, operculum; 11c,e, head-foot; 12c, female genitalia) Diagnosis: Shell with 2.10-3.63 (mean 3.24, males; 3.26, females) weakly to moder- ately convex teleoconch whorls (convexity ra- tio 0.16-0.24; mean 0.17, males; 0.18, females). Aperture oval with inner lip attached to parietal wall over most of length. Colour yellowish to chocolate brown. Operculum with calcareous smear 0-0.4 mm long (mean 0.22 mm, males; 0.21, females). Shell (Figs. 7c, 14d, 53c,e; 9e, protoconch) as for diagnosis. See Table 18A for measure- ment data. Operculum (Fig. 8c) with 1-4 (mean 2.80, males; 2.57, females) pegs, 0.02—0.29 mm (mean 0.10 mm, males; 0.11 mm, females) high. See Table 18A for measurements. Radula as for species. See Table 3 for data. Head-foot (Fig. 11c,e) as for species; dor- sal cephalic tentacles uniformly lightly to darkly pigmented, sometimes with narrow, ae unpigmented stripe bordered with dark ines. Anatomy (Fig. 12c, female genitalia) as for species. See Tables 18B-E for dimensions. Type material: holotype (Fig. 14d) (SAM, D.17920, 009); and paratypes (008, AMS, C.152860, 2; 685, AMS, C.152861, many; 739, AMS, C.152862, many). Dimensions of holotype: length 4.27 mm, width 2.45 mm, length of aperture 1.86 mm. Localities: Middle Springs: Horse Springs East (747A,B, 748A-C), Horse Springs West (746A,B), Mt. Hamilton Homestead (006), Strangways Spring (745A), Blanche Cup Spring (008, 685,739), Little Bubbler Spring (744A-C), Bubbler Spring (013), unnamed springs, Blanche Cup Group (786, 787), Cow- ard Springs (019, 764A-C), Kewson Hill Springs (740, 741, 742A,B, 765), Elizabeth Springs (766A-F, 767A,B, 771A-C), Julie Springs (772A-D, 773A,B), Jersey Springs (683A,B, 769A,B, 770A), Warburton Spring (681A-C, 682), Beresford Spring (028). South Western Springs: Billa Kalina Springs (026, 723A-D, 759A, 761A-C, 762A,B, 763A,B), Francis Swamp (717B,C, 720A,B, 721A-C), Strangways Springs (007, 029—030, 678A,B, 679A-C). Shells only from Margaret Spring (722). Northern Springs: Brinkley Springs (677), Hawker Springs (670B,C, 671, 672A-D, 673), Fountain Spring (031-033), Twelve Mile Spring (036,037), Big Perry Spring (034), Outside Springs (038-040, 041) (Fig. 13). Remarks: This form is the large aquatic species living in the Middle, South Western and Northern Springs, replacing F. accepta, which occurs in the Southern Springs. Specimens from the Kewson Hill Springs and, to a lesser extent Elizabeth, Jersey and Julie Springs, tend to have stunted shells (Figs. 7c, 53c) and smaller gills with fewer filaments than have other populations of this form. The only important characters consis- tently separating these populations are peg height (PH) and the length of the calcareous smear (PC) and these, together with the val- ues of PH/OL and PC/OL, are significantly dif- ferent from those of all other populations of F. aquatica. Peg number also tends to be less, but not consistently so. The non-opercular dif- 32 PONDER, HERSHLER & JENKINS FIG. 14. Shells of species of Fonscochlea. a. Fonscochlea zeidleri form A, holotype. Coward Springs (764). b. Fonscochlea aquatica form B. Freeling Springs (665) (ЗАМ, 0.17921). с. Fonscochlea zeidleri form В. Big Cadnaowie Spring (661) (SAM, D.17916). d. Fonscochlea aquatica form A, holotype. Blanche Cup Spring (009). AUSTRALIAN SPRING HYDROBIIDS 33 % -6 -4 2 0 2 4 6 FIG. 15. Plot of group centroids, using the first two canonical axes, obtained from discriminate analysis of populations of large aquatic species and forms of Fonscochlea using shell and opercular measurements. Males and females of each population are, for the purposes of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: SH, 50.15%; SW, 41.40%; АН, 74.33%; TW, 53.49%; OL, 91.57%; РН, 78.06%; PC, 35.01%; PN, 38.94%. Second (vertical) axis: SH, 0.18%; SW, 19.15%; АН, 6.39%; TW, 2.14%; OL, 4.03%; РН, 13.72%; РС, 47.09%; РМ, 0.06%. a, F. accepta form А; с, Е. aquatica form В; f, Е. accepta form В; К, F. aquatica cf. form А; а, Е. aquatica form A, typical; 1, F. accepta form С. 34 PONDER, HERSHLER & JENKINS = =3 -8 -4 0 A FIG.16. Plot of group centroids, using first and third canonical axes, obtained from discriminate analysis of populations of large aquatic species and forms of Fonscochlea using shell and opercular measurements. Males and females of each population are, for the purpose of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: SH, 50.15%; SW, 41.40%; AH, 74.33%; TW, 53.49%; OL, 91.57%; PH, 78.06%; PC, 35.01%; PN, 38.94%. Third (vertical) axis: SH, 0.42%; SW, 0.04%; AH, 0.32%; TW, 0.13%; OL, 0.52%; PH, 5.62%; PC, 7.36%; PN, 10.35%. a, Е. accepta form А; с, Е. aquatica form В; +, Е. accepta form В; К, F. aquatica cf. form А; q, F. aquatica form A, typical; t, F. accepta form C. ferences are not consistent within the geo- but we do not judge them to be of sufficient graphic area in which the form occurs. The magnitude to regard this form as a species, opercular and pallial differences are important given the degree of overlap with typical F. ( AUSTRALIAN SPRING HYDROBIIDS 35 aquatica form A. These differences are as great as or greater than those between some groups of populations recognised here as dis- tinct geographic forms but because these populations do not occupy a geographic area clearly separate from that of F. aquatica form A, it is not formally differentiated. These pop- ulations are recognised in the discussion be- low as F. aquatica cf. form A but are included in the diagnosis of form A above. They form a separate group when opercular and shell data are lumped together using discriminate ana- lysis (Figs. 15,16). The Kewson Hill popula- tion (stn 741) in particular, has most shell measurements significantly different from all other populations of this species (including 683 and 767) and also differs from all popu- lations (except stn 679) in the ratio BW/WH, but not in other shell ratios. Discriminate ana- lysis using pallial measurements also sepa- rates the Jersey-Elizabeth-Kewson Hill popu- lations from typical F. aquatica form A (Figs. 175418): Somewhat surprisingly, there do not ap- pear to be any consistent differences be- tween the populations in the Northern and Blanche Cup Springs; despite their consider- able separation, these group very closely in all the analyses. It is suggested below that the presence of F. aquatica form A in springs of the Middle Springs might be due to a rela- tively recent introduction to some of those springs, but that the form in the springs be- tween Jersey Springs and Kewson Hill might be an earlier stock that differentiated at an infraspecific level. Biochemical evidence is required to determine the status of these pop- ulations. Fonscochlea aquatica form B. (Figs. 7f, 14b, shell; 8f, operculum; 10f, rad- ula) Diagnosis: Shell with 3.0 to 3.7 (mean 3.30, males; 3.33, females) teleoconch whorls, with more convex (convexity ratio 0.18-0.25; mean 0.21, males; 0.23, females) teleoconch whorls than is usual in typical form. Aperture more nearly circular than in typical form, with inner lip attached to parietal wall over shorter distance. Colour reddish to orange-brown. Operculum with calcareous smear (0.26— 0.60 mm; mean 0.39 mm, males; 0.37 fe- males) longer than in typical form. Shell (Figs. 7f, 14b), see diagnosis. See Ta- ble 18A for measurements. Operculum (Fig. 8f) as for species. Calcar- eous smear longer than in typical form. See Table 18A for measurements. Radula (Fig. 10f) as for species. See Table 3 for data. Head-foot as for species (preserved mate- rial only examined) except for distinct, dark, black to dark grey, dorsal stripe on tentacles of most individuals; rarely with short white stripe. Anatomy as for species. See Tables 18B-E for measurement data. Voucher material: primary voucher speci- men (Fig. 14b) (SAM, D.17921, 665A); addi- tional material from this station (665A, AMS, С.152863, many, C.152997,1, figured; 665B, AMS, C.152864, many; 665C, AMS, C.152865, many); 664A, AMS, C.152866, many; 664B, AMS, C.152867, many; 664C, AMS, C.152868, 32; 045, AMS, C.152869, 25; 046, AMS, C.152870, many. Dimensions of primary voucher specimen: length 4.59 mm, width 2.47 mm, length of ap- erture 1.98 mm. Localities: Freeling Springs (042-044, 045-046, 663, 664B,C, 665А-С). Remarks: The Freeling Springs form of F. aquatica is consistently and readily distin- guishable at sight from specimens in the springs farther southeast, the more convex teleoconch whorls and reddish colour in par- ticular, being distinctive features. The circular aperture is probably correlated with the more convex whorls and the shorter area of attach- ment of the inner lip of the aperture to the parietal wall. This form separates well from related taxa by discriminate analysis using shell and oper- cular measurements (Figs. 15, 16) and is also separated from F. aquatica form A using pal- lial measurements (Figs. 17, 18). Discrimination of the large aquatic taxa of Fonscochlea and their forms was tested us- ing discriminate analysis on shell and opercu- lar measurements and pallial measurements. The results showed that all groups could be discriminated using these data, with 85% of all measured individuals (n = 625) being clas- sified correctly with the shell + opercular data and 78% of the specimens (n= 103) us- ing the pallial measurements. The Euclidian (taxonomic) distances between the groups are given in Table 4. With shell and opercular data the greatest distance score when sexes were treated as separate populations was 2.69 between F. aquatica cf. form A and F. accepta form A. All of the pairwise compari- sons between F. aquatica and F. accepta 36 PONDER, HERSHLER & JENKINS 27 -5 -3 -1 1 3 5 FIG. 17. Plot of group centroids, using first two canonical axes, obtained from discriminate analysis of populations, sexes combined, of large aquatic species and forms of Fonscochlea using pallial measure- ments. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: LC, 16.32%; WC, 77.51%; FC, 52.54%; AC, 78.58%; HC, 59.24%; LO, 46.76%; WO, 29.30%; DO, 1.12%, СО, 37.69%. Second (vertical) axis: LC, 19.95%; WC, 5.70%; ЕС, 30.44%; АС, 1.57%; НС, 33.13%; LO, 0.04%; WO, 6.27%; DO, 47.12%, CO, 8.90%. а, Е. accepta form А; с, Е. aquatica form В; +, Е. accepta form В; К, F. aquatica cf. form А; q, Е. aquatica form A, typical; t, F. accepta form С. | AUSTRALIAN SPRING HYDROBIIDS 37 2 5 3 1 1 3 5 7 FIG. 18. Plot of group centroids, using first and third canonical axes, obtained from discriminate analysis of populations, sexes combined, of large aquatic species and forms of Fonscochlea using pallial measure- ments. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: LC, 16.32%; WC, 77.51%; FC, 52.54%; AC, 78.58%; HC, 59.24%; LO, 46.76%; WO, 29.30%; DO, 1.12%, CO, 37.69%. Third (vertical) axis: LC, 6.38%; WC, 0.62%; FC, 0.01%; AC, 12.12%; HC, 2.07%; LO, 4.27%; WO, 36.13%; DO, 10.62%, СО, 0.30%. a, F. accepta form А; с, Е. aquatica form В; f, Е. accepta form В; К, Е. aquatica cf. form A; q, Е. aquatica form A, typical; 1, F. accepta form С. scored >0.95 (all but one >1.0, the lowest distance score between females of F. aquat- ica form B and F. accepta form C). All of the pairwise comparisons between the groups within A. aquatica scored >0.37 (all but one >0.5, the lowest distance score between males of F. aquatica forms A and B). Within F. accepta all groups scored >0.13 (all but one >0.44, the lowest distance score be- tween males of F. accepta forms A and C). Using pallial data the distance scores be- tween F. aquatica and F. accepta were >0.39 (all but two >1.0, the lowest scores between F. адиайса cf. form A and F. ac- cepta forms A and B, reflecting the reduced gill in this form of F. aquatica). The greatest scores (>9.3) were between F. aquatica form A and F. accepta forms A and B. Within F. accepta the forms had distance scores >0.19, this score being between forms A and B, form C having a score of >2.7 when con- trasted with the other two forms. The groups within F. aquatica separated with scores >3.2, that between form A and cf. A being 57. SNK tests (5% level) using pooled data, 38 PONDER, HERSHLER & JENKINS combined and separate sexes, for each vari- able used in the discriminate analyses gave these results. Shell and opercular characters: SH—Combined sexes: significantly differ- ent for both species and all forms except F. accepta form С and Г. accepta form A. Sep- arate sexes: the same result except for F. aquatica form А, F. aquatica cf. form A and F. aquatica form B overlapping. The means for this character were not significantly different between males and females except for the two forms of F. aquatica (females larger). SW—Combined sexes: means significantly different for F. accepta form B and F. accepta form A + F. accepta form C. Separate sexes: F. accepta form B, F. accepta form A + F. accepta form C + F. aquatica cf. form A and F. aquatica form A + F. aquatica form B are significantly different subsets. Only F. aquat- ica form A shows significant sexual dimor- phism for this character. AH—Combined sexes: significantly differ- ent for all forms of both species. Separate sexes: five subsets are discriminated; F. ac- cepta form B, F. accepta form A + F. accepta form C, F. aquatica cf. form A + F. aquatica form B, F. aquatica form A male and female. Sexual dimorphism is apparent in only F. aquatica form A. TW—Combined sexes: significantly differ- ent for the two forms of F. aquatica, the forms of F. accepta overlapping but, together, being significantly different from F. aquatica. Sepa- rate sexes: two groups of overlapping subsets are discriminated; one with F. accepta (all forms) + F. aquatica cf. form A, the other with F. aquatica form A + F. aquatica form B. This character does not significantly differ between males and females. OL—Sexes combined: same result as for : SH. Separate sexes: two groups of overlap- ping subsets are discriminated that corre- spond to the same groups as for the last vari- able (TW). There was no significantly different sexual dimorphism. PH—Combined sexes: significantly differ- ent for F. aquatica form A, F. aquatica form B + F. accepta form В and F. accepta form A + F. accepta form C. Separate sexes: all form overlapping subsets except F. aquatica cf. form A. None show significant differences be- tween sexes in this character. PC—Combined sexes: means significantly different for the two forms of F. aquatica and these both separate from F. accepta, the forms of that species not being discriminated. Imm FIG. 19. Shells of species of Fonscochlea. a. Fonscochlea variabilis form A, holotype. Blanche Cup Spring (009). b. Fonscochlea variabilis form A, Bubbler Spring (013) (AMS, C.153001). c. Fonscochlea variabilis form C, Freeling Springs (045) (AMS, C.152882). d. Fonscochlea billakalina, holotype. Old Billa Kal- ina Spring (027). Separate sexes: three groups are discrimi- nated, F. aquatica cf. form A, F. aquatica form B and, the third (intermediate) group with the rest. There is no sexual dimorphism in this character. PN—Combined sexes: all overlap except F. aquatica form A. Separate sexes: all overlap except F. aquatica cf. form A. There is no significant sexual dimorphism in this charac- ter. It is clear from these results that the Jersey Springs-Kewson Hill form of F. aquatica is very distinct, as is also demonstrated with the pallial characters below. Pallial characters (combined sexes only given here): LC—F. accepta form B + F. aquatica cf. form A + F. accepta form A are AUSTRALIAN SPRING HYDROBIIDS 39 FIG. 20. Blanche Cup pool and upper outflow (Stn. 739), showing location of the 11 sampling sites for study of size-variation in Fonscochlea variabilis. not separated but F. aquatica form B is sig- nificantly different from that subset and from a subset formed by F. accepta form C and F. адиайса form A. WC—F. адиайса cf. form A is significantly different from all other forms, which form overlapping subsets. FC—F. адиайса form A is significantly dif- ferent from all others, which form overlapping subsets. AC—There are no significant differences between any two forms. HC—Three subsets are separated, one with F. aquatica cf. form A + F. accepta form B, another with F. accepta form C and the third (intermediate in size) with the three re- maining forms. LO—There are no significant differences between any two of the forms. WO-—-All forms contained in overlapping subsets. DO—Three different subsets are discrimi- nated, one with the forms of F. accepta, the intermediate one with F. aquatica cf. form A + F. aquatica form B and the third with F. aquatica form A. Group 2: the small aquatic species. Fonscochlea variabilis n.sp. Derivation: a reference to the variable shell of this species. Diagnosis: Shell small (up to 3.5 mm long), conical, with 2-3.4 weakly to moderately con- vex (convexity ratio 0.05-0.30) teleoconch whorls. Aperture expanded in some popula- tions, not in others. Inner lip narrow and loosely attached to parietal wall or separated from it. Colour pale to dark brown. Operculum with 1-7 strong pegs, peg height 0.06- 0.2 mm. Shell (Figs. 7e, 19a-c, 22a,c, 23d-f,h,i, 25b) see diagnosis. Operculum (Fig. 8e) with strong pegs. Radula (Fig. 10e) as for genus. Inner mar- ginal with 9-15 cusps. See Table 3 for other details. Head-foot (Fig. 24a,b,d,e) variably pig- mented; cephalic tentacles with unpigmented narrow, dorsal stripe margined with pale grey to black lines. Cephalic tentacles and snout very pale grey to black, black around eyes or just behind eyes. Anatomy (Fig. 27a,d, female genitalia) sim- ilar to other species in subgenus. No consis- tent significant anatomical differences be- tween this species and F. conica noted, although data limited. The typical form of this species is described below as “form A” where a holotype is des- ignated for the species. Localities: Middle, Northern and Freeling Springs. Remarks: This species and two others, F. conica and F. billakalina, comprise the small aquatic group. They tend to prefer the upper outflow and spring head (Fig. 54) and to at- tach themselves to the undersides of hard ob- jects (stones, wood, bones, etc.). Some populations of this species show considerable variation, sometimes a dimor- phism, in size that does not seem to be sex- ually based. See the remarks on form A of this taxon for a detailed analysis and discussion of one of these populations. Apart from size-related differences, the three “small aquatic” species differ from F. aquatica and F. accepta in having the seminal receptacle displaced more posteriorly relative to the coiled oviduct (compare Figs. 12, 27). Fonscochlea variabilis form A. (Figs. 19a,b, 23d-f, shell; 24a,b,d,e, head- foot; 27a,d, female genitalia) Shell 1.8-2.8 mm (mean 2.28, males; 2.42, females) in length, width/length ratio 0.58— 0.65, with 2.00-3.38 moderately convex te- leoconch whorls (convexity ratio 0.05—0.30, 40 PONDER, HERSHLER & JENKINS TABLE 5. Descriptions of 11 stations in the Blanche Cup pool and upper outflow (Stn. 739) sampled for the study of shell variation in Fonscochlea variabilis. Comments 30-60% covered by short sedge, sandy bottom. mat of dead sedge on its side, mud bottom. mat of filamentous algae lying between sedges. bottom sample, 5% algal cover, some dead sedge. sample from sedges (20-30% cover). beyond edge of dense sedge mats, bottom consisting of dead, algal-covered sedge and water weed. Distance from Water Station edge of pool depth 1 2-5 cm 1-2 cm 2 20 cm 3 ст 3 1.8 т -- 4 2.8 т 15 ст 5 2.8 т 15 ст 6 5т 30 ст TL 2m 10 cm 8 2m 10 cm 9 4.5 т 10 — <2 cm 11 — <2 cm mean 0.18) and aperture not markedly ex- panded. Operculum with strong pegs. Shell (Figs. 19a,b, 23d), see diagnosis. See Table 19A for measurements. Operculum with 1-5 (mean 2.96, males; 3.14, females) strong pegs 0.09-0.2 mm (mean 0.14 mm, males; 0.15 mm, females) in height, calcareous area 0.16-0.34 mm (mean 0.24 mm) long. See Table 19A for measurements. Radula as for species. See Table 3 for de- tails. Head-foot (Fig. 24a,b,d,e) typically darkly pigmented with distinctive, triangular patch of black pigment behind eyes and patch of dense white granules anterior to, and on inner side of eyes. Small form of F. variabilis occur- ring at Blanche Cup Spring (see below) paler than large form (compare Fig. 24a,d), with pale grey snout and unpigmented tentacles. Anatomy (Fig. 27a,d, female genitalia) as for species. See Tables 19B-C for measure- ments. Type material: holotype (Fig. 19a) (SAM, D.16275, stn 009); and paratypes (008, SAM, D.3208, 74, AMS, C.152873, 1; 009, AMS, C.152871, many; 010, AMS, C.152874, 50; 011, AMS, C.152875, 30; 739, AMS, С.152931, 5). Dimensions of holotype: length 2.45 mm, width 1.47 mm, length of aperture 1.07 mm. Localities: Middle Springs: Blanche Cup Spring (008-012, 685, 739), Little Bubbler Spring (744A-C), Bubbler Spring (013-017), unnamed spring in Blanche Cup Group (786), Coward Springs Railway Bore (018, 684, 743) (Fig. 26). Remarks: This form of F. variabilis and F. conica are found in the Blanche Cup Group middle of sedge zone, sparse (30%) cover. as in (7), but in densely covered (60%) area. 1m fine sand bottom. outflow, under stones. outflow, filamentous algae. although not in the same springs. Fonscoch- lea variabilis is found in the larger springs, whereas F. conica is restricted to the small springs. This is the only detected example of parapatry of any taxa in the two species groups of Fonscochlea. Collections from Blanche Cup (Stn 739) contained not only typical Fonscochlea vari- abilis form A (SH, 2.0-2.7 mm), but also a smaller, adult (SH, <1.8 mm) “form,” with a complete and thickened aperture. Possible explanations for the presence of these two phenotypes include sexual dimorphism, sym- patry of congeners (the second species being Fonscochlea conica or another unnamed species), seasonal classes of F. variabilis form A that attained different sizes at maturity, and distinct ecomorphs of F. v.variabilis. In an effort to determine the significance and nature of this apparent size bimodality, the following data were gathered and analyzed. Samples were taken from 11 stations in the pool and upper outflow of Blanche Cup (Fig. 20, Table 5), encompassing a range of micro- habitats and including samples along a transect from the edge to the center of the pool. Stations 1-9 were sampled on 31/8/83 while Stations 10 and 11 were sampled on 27/11/83. A fine sieve having a mesh size of 1 mm was used to sample soft sediment and aquatic vegetation. At Station 10 snails were collected by washing them from the under- sides of stones into a container. A maximum of five minutes of sampling was done at each station and the snails were preserved in for- malin for later study. No snails were found at Stations 3, 6, and 9. From each sample, 50 mature small aquatic Fonscochlea having a “mature” aper- AUSTRALIAN SPRING HYDROBIIDS 41 TABLE 6. Shell height statistics for Fonscochlea variabilis from 8 stations at Blanche Cup (Stn. 739). мэм 53 —— Males Station x SD 1 2.13 0.217 2 2.19 0.208 4 2.26 0.205 5 2.25 0.15 74 2.26 0.257 8 2.19 0.259 10 1.78 0.33 11 1277 0.315 Shell Height (mm) Females N X SD N 23 2.26 0.272 27 32 2.20 0.235 18 29 2.38 0.142 21 32 2.36 0.199 18 24 2.31 0.222 26 23 2.24 0.193 27 25 1.87 0.444 25 24 2.19 0.333 26 ture were selected at random and their shell heights were measured with the digitizing pad, for size-frequency analysis. The shells were then cracked and the snails sexed. The small aquatic snails from a large sam- ple obtained by general collecting at Blanche Cup on 29/8/83 were roughly sorted into typ- ical F. variabilis form A and the small “form.” Fifty-seven of the former and 55 of the latter were selected at random and all shell param- eters were measured with the digitizing pad. The shells were then cracked, the snails sexed and the opercular data were obtained. Size-frequency histograms, sexes sepa- rate, for the shells measured from the various stations are given in Fig. 21 and appropriate statistics are shown in Table 6. The small “form” was almost totally absent from the pool samples. Noteworthy is the lack of bimo- dality and paucity of snails of SH less than 1.87 mm in these samples (Fig. 21). The two samples from the outflow (10, 11) had large numbers of the small “form” (SH <1.69 mm) as well as typical F. variabilis form A. The results of a pairwise comparison, sexes sep- arate, of shell height among all stations (SNK Test, null hypotheses of equality of shell height rejected at P = 0.01) are given in Table 7. There is little difference in shell height among the 6 stations in the pool, with only 4 of 30 possible comparisons having a significant difference. However, the two out- flow samples (Stations 10, 11) do differ sig- nificantly in shell height for most pairwise comparisons with the pool samples: for Sta- tion 10, all possible comparisons (12 of 12) are significantly different; for Station 11, seven of 12 comparisons are significantly dif- ferent. Note that shell height for females from Station 11 generally does not differ signifi- cantly from that of the pool samples. While the histograms for the samples from the outflow suggest bimodality in size within sexes, the sample sizes are too small to pro- vide statistically significant evidence of such bimodality. It is evident from the histograms that the apparent size bimodality is not due simply to sexual dimorphism: while females are generally larger than males, the outflow samples include both male and female snails assignable to the small “form”, as well as nor- mal-sized males and females. Typical individuals of both sexes of F. vari- abilis form A and the small “form” were found to differ significantly (LSD Test, null hypothe- ses rejected at P = 0.01) in all shell and oper- cular parameters, excluding convexity, as well as the following ratios: PD/SH, SW/SH, AH/ SH, and PC/OL. While these data suggest that two distinct phenotypes are indeed present in Blanche Cup, we do not have sufficient evi- dence at this point to separate them as spe- cies, or to determine whether they represent ecomorphs, seasonal classes, or different species. At this point, we consider them, ten- tatively, as forms of F. variabilis form A. The measurement data for the small form are not included in the summary of measurement data of F. variabilis, but are shown as separate data in Table 19. The small form is also treated individually in the discriminate analysis and it groups separately from typical F. variabilis form A and F. conica (Figs. 28—30; Table 8). Using discriminate analysis on shell and opercular measurements this form, excluding the small Blanche Cup form, separated rather well from the other small aquatic taxa of Fons- cochlea (Figs. 28—30; Table 8), although with a small amount of overlap with F. conica. Fonscochlea variabilis form B. (Figs. 7e, 22c, 23h,i, 25b, shell; 8e, opercu- lum; 10e, radula) Diagnosis: Shell 2.09-3.48 mm (mean 42 PONDER, HERSHLER & JENKINS A 10 5 o B 5 0 n > < а > € Q = œ a = 5 2 5 0 D 115-132 133-150 151-168 169-186 187-204 205-222 223-240 241-258 259-276 277-294 A SHELL LENGTH (mm) FIG. 21. Size-frequency histograms for Fonscochlea variabilis from eight stations at Blanche Cup (Stn. 739). Darkened columns, males; white columns, females. A. Pool stations. A, stn 2; В, stn 1; С, stn 8; D, stn 5. В. Pool and outflow stations. A, stn 11; В, stn 10; С, stn 4; D, stn 7. NUMBER OF INDIVIDUALS AUSTRALIAN SPRING HYDROBIIDS 43 A 5 0 B 10 5 о 10 C 5 0 10 D 5 115-132 133-150 151-168 169-186 187-204 205-222 223-240 241-258 259-276 B SHELL LENGTH (mm) 44 PONDER, HERSHLER & JENKINS TABLE 7. Significant differences (SNK Test, P = 0.01) in shell height of Fonscochlea variabilis among stations at Blanche Cup (Stn. 739). Empty boxes indicate shell height for males or females does not differ significantly between that pair of stations. Station 1 2 4 1 == 2 =, 4 F F — 5 M Uf M 8 10 M,F M,F M,F 11 M M M,F Station 5 7 8 10 11 M,F M,F M,F — M M M F — FIG. 22. Shells of species of Fonscochlea. a. Fonscochlea variabilis form C. Freeling Springs (664) (SAM, D.17913). b. Fonscochlea conica, holotype. Welcome Springs (003). c. Fonscochlea variabilis form B. Twelve Mile Spring (036) (SAM, D.17912). Scale: 1тт. Scale A: a,c,; scale В: b. 2.58 mm, males; 2.79 mm, females) in length with width/length ratio of 0.57—0.62, thus gen- erally narrower than form A, but not consis- tently so. Teleoconch whorls 2.38-3.5 (mean 2.89, males; 2.98, females), convex (con- vexity ratio 0.10-0.25; mean 0.16, males; 0.19, females) and aperture noticeably ex- panded. Operculum with well-developed egs. Ñ Shell (Figs. 7e, 22c, 23h,i, 25b), see diag- nosis. See Table 19A for measurements. Operculum (Fig. 8e) with 2-7 (mean 3.88, males; 4.85, females) well-developed pegs 0.06-0.16 mm (mean 0.10 mm, males; 0.11 mm, females) long, calcareous area 0.16-0.47 mm (mean 0.28 mm, males; 0.31 mm, females) long. Calcareous area longer and PH/OL smaller than in most spec- ¡mens of Е. variabilis form A. See Table 19A for measurement details. Radula (Fig. 10e) as for species. See Table 3 for data. Head-foot not observed in living material but generally similar to form A except median dorsal unpigmented band on tentacles usu- ally very narrow or absent but black lines usu- ally present. Background pigmentation dark grey to black. Anatomy as for species. See Tables 19B-C for measurements. Voucher material: primary voucher speci- men (Fig. 22c) (ЗАМ, 0.17912, stn 036); ad- ditional material from same station (SAM, D.2031, 9; 037, AMS, C.152876, many; 036, AMS, C.152877, many; 1003A, AMS, AUSTRALIAN SPRING HYDROBIIDS 45 TABLE 8. Summary of results of discriminate analysis of shell + opercular (right side) and pallial characters (left side) of small aquatic species of Fonscochlea. The numbers are the Euclidean (taxonomic) distances between the groups. F.va.A f.va(small) F. variabilis form A x 2.268 1.792 F. variabilis (small form) 3.421 x F. variabilis form B 1.480 3.382 F. variabilis form C 1.506 3.421 F. conica 0.660 1.376 F. billakalina 1.524 1.683 Left side: Combined sexes. C.152878, many; 1003B, AMS, 0.152879, many; 1003C, AMS, C.152880, many; 10030, AMS, С.152881, 20; 037, AMS, C.152929, 3). Dimensions of primary voucher specimen: length 2.95 mm, width 1.58 mm, length of ap- erture 1.21 mm. Localities: Northern Springs: Hawker Springs (670A-C, 672A,B,D, 673), Fountain Spring (031-032), Twelve Mile Spring (035— 037, 1003A-D), Big Perry Springs (034), Out- side Springs (038, 040) (Fig. 26). Remarks: This form is not readily separable from F. variabilis form A quantitatively on any single character. Shells are generally separa- ble on the characters given in the diagnosis, although there is considerable overlap. Using discriminate analysis on a subset of shell measurements and opercular measurements, F. variabilis form B separated rather well from Е. variabilis form A and F. conica (Figs. 28— 30; Table 8). Fonscochlea variabilis form С (Figs. 19c, 22a, shell) Diagnosis: Shell similar to F. variabilis form B but typically relatively broader than most populations of that form (width/length ratio 0.60-0.62), thicker (i.e. more solid) and sometimes larger (length 2.31-3.48 mm; mean 2.60 mm, males; 2.84, females). Oper- culum with well-developed pegs and long cal- careous smear. Shell (Figs. 19c, 22a) with 2.25-3.25 F.va.B F.va.C F.conica F.bill. Right side: 1.780 1.444 0.724 1.584 Female 1.003 1.478 0.697 1.613 Male 3.953 3.662 1.577 1.684 DO 3.139 13127. 1.714 X 0.446 2.440 3.283 0.502 1.661 2.492 0.162 X 2.139 2.899 2.978 2.978 2.073 2115 X 1.283 1.395 2.906 2.908 Sait X (mean 2.84, males; 2.96, females) teleoconch whorls, convexity ratio 0.16-0.25 (mean 0.23, males; 0.20, females), see diagnosis for other details. See Table 19A for measure- ments. Colour brown to reddish-brown. Operculum with 3-6 (mean 4.36, males; 4.44, females) well-developed pegs 0.11- 0.17 mm (mean 0.13 mm, males; 0.16 mm, females) in height, calcareous smear 0.31— 0.50 mm (mean 0.37, males; 0.43, females), generally longer than in other forms of this species (but close to F. variabilis form B) and therefore PC/OL ratio significantly different. See Table 19A for measurement details. Radula as for species. See Table 3 for data. Head-foot as for species. Not examined in living material. Anatomy as for species. See Tables 17B-C for measurements. Voucher material: primary voucher speci- men (Fig. 22a) (ЗАМ, 0.17913, stn 664B); additional material from same station (045, AMS, C.152882, 1, figured; 045, AMS, C.152883, many; 664A2, AMS, C.152884, many; 664A1, AMS, C.152889, 16; 664B, AMS, C.152885, many); 665A, AMS, C.152886, many; 665B, AMS, C.152887, many; 665C, AMS, C.152888, 50; 046, AMS, C.152890, 5. Dimensions of primary voucher specimen: length 3.25 mm, width 2.00 mm, length of ap- erture 1.50 mm. Localities: reeling Springs (042-043, 045-046, 663, 664A,B, 665A-C) (Fig. 26). Remarks: Specimens of this form are ald (À à Aad FIG. 23. Shells of Fonscochlea billakalina and F. variabilis. a-c. Fonscochlea billakalina. Strangways Springs (679), showing size variation (AMS, C.152967). d-e. Fonscochlea variabilis form A, Blanche Cup Spring (739), showing size variation (paratypes, AMS, С.152931). f. Fonscochlea variabilis, small form from Blanche Cup Spring (739) (АМ$, С.155863). 9. Fonscochlea billakalina, Strangways Springs (678) (AMS, C.152969). h,i. Fonscochlea variabilis form В. Twelve Mile Spring (037), showing size variation (AMS, C.152967). readily distinguished from other populations small number of quantifiable differences. Dis- of F. variabilis on shell characters despite a criminate analysis separated the single mea- AUSTRALIAN SPRING HYDROBIIDS 47 sured population of this form from the rest of the small aquatics (Figs. 28-30; Table 8). This is one of four “taxa” endemic to Freeling Springs. Fonscochlea conica n.sp. Derivation: a reference to the conical shape of the shell. (Figs. 22b, 53b,f, shell; 9f, protoconch; 24f,g, head-foot; 27b, female genitalia). Diagnosis: Shell small (1.41—2.83 mm long; mean 1.94mm, males; 2.07 mm, females), conical, with 2.0-3.2 (mean 2.57, males; 2.67, females) weakly to moderately convex (convexity ratio 0.04-0.24; mean 0.13, males; 0.16, females) teleoconch whorls. Ap- erture not expanded; inner lip narrow, usually attached to parietal wall; outer lip slightly prosocline. Colour of shell ranges from yel- lowish brown to dark brown or orange-brown. Operculum with strong pegs. Head-foot lightly pigmented except for black triangle behind eyes. Shell (Figs. 22b, 53b, f; 9f, protoconch), see diagnosis. Measurement data in Table 19A. Operculum with 1-5 (mean 2.48, males; 2.64, females) strong pegs 0.05-0.17 mm (mean 0.10 mm, males; 0.11 mm, females) in height, calcareous area 0.08-0.29 mm (mean 0.17 mm, males; 0.18 mm, females) long. See Table 19A for measurement data. Radula as for genus. Inner marginal teeth with 14-18 cusps. See Table 3 for other de- tails. Head-foot (Fig. 24f,g) is lightly pigmented with grey or pale grey, snout and cephalic ten- tacles very pale grey or unpigmented. Con- spicuous black triangle behind eyes. Cephalic tentacles with inconspicuous pale dorsal line in posterior quarter to half. Anatomy (Fig. 27b, female genitalia) very similar to that of F. variabilis except in size- related characters. See Tables 19B-E for measurement data. Type material holotype (Fig. 22b) (SAM, D.17914, stn 003); and paratypes (003, AMS, C.152895, many; 756A, AMS, C.152896, 6; 756B, AMS, 0.152897, many; 756C, AMS, C.152898, many). Dimensions of holotype: length 2.15 mm, width 1.16 mm, length of aperture 0.90 mm. Localities: Southern Springs: Welcome Springs (003, 755A,B,D, 756A-C), Davenport Springs (004, 005, 753A,B), Old Woman Spring (733B). Shells have been found at Fin- niss Swamp West (690), Venable Spring (687) and Priscilla Spring (686). Middie Springs: Horse Springs East (747A,B, 748A-C), Horse Springs West (746), Strangways Spring (007, 745A), an un- named spring in Blanche Cup Group (739, 785, 787), Coward Springs (019-022, 023, 764A-C), Kewson Hill (741, 742A, 765), Julie Springs (772A,B,D, 773A-C), Elizabeth Springs (024, 766A,C-E, 771A-C), Jersey Springs (025, 683A,B, 768A,B, 769A,B, 770A,B), Warburton Spring (681A-C, 682). Beresford Spring (028) (Fig. 26). Remarks: The shells of the specimens as- signed to this species are smaller, more com- pact and more solid than are those of most specimens of F. variabilis. These two species do not occupy the same spring groups, ex- cept in the Blanche Cup Group in which F. conica is found in small springs and F. vari- abilis form A in the larger springs. The smaller, more conical shells and pale head-foot serve to distinguish this species from F. variabilis in the Blanche Cup Group and elsewhere. Because the protoconchs in both species have a similar diameter, the PD/ SH ratio is significantly larger in nearly all populations of F. conica compared with F. variabilis, reflecting the generally larger shell of F. variabilis. The radulae also differ in the two species, F. conica having more cusps on the inner lateral teeth than do most speci- mens examined in the F. variabilis complex. Discriminate analysis using shell and oper- cular measurements separated the popula- tions of F. conica and F. variabilis well, al- though there is minor overlap with F. variabilis form A in the plot using the first and second axes. F. variabilis form B is well separated except in the plot using the second and third axes. Despite the lack of any single character that consistently and significantly separates all in- dividuals of F. conica from all individuals of F. variabilis, they are recognised as distinct spe- cies because of their virtually sympatric asso- ciation in the Blanche Cup Group. The differ- ences in radulae and in the pigmentation of the head-foot noted above reinforce the re- sults of the discriminate analysis using the quantifiable shell and opercular differences. It is, however, freely admitted that the relation- ships of all of the small Fonscochlea are by no means clear and further analysis using elec- trophoretic methods is required to resolve the somewhat tentative arrangement proposed here. 48 PONDER, HERSHLER & JENKINS FIG. 24. Dorsal views of heads of species of Fonscochlea and Trochidrobia punicea. All figures except i from living material. a, d. Fonscochlea variabilis, Blanche Cup Spring. a, form A, typical; d, small form. b. Fonscochlea variabilis form A, Bubbler Spring, right tentacle only, showing the unpigmented stripe on the tentacle in this population. The remainder of the head is similar to that in a. c. Fonscochlea billakalina, Old Billa Kalina Spring. e. Fonscochlea variabilis form A, Coward Springs Railway Bore. f,g. Fonscochlea conica; f, Welcome Springs; д, Elizabeth Springs. h. Trochidrobia punicea, Blanche Cup Spring. 1. Fonscochlea aquatica cf. form A, Elizabeth Springs, showing abnormal tentacle development (from pre- served specimen). Scale: 0.2mm. Fonscochlea billakalina n.sp. operculum; 24c, head-foot; 27c, female gen- italia). Derivation: refers to Billakalina Station on Diagnosis: Shell similar to F. variabilis and which many of the springs containing this Е. conica but operculum differs markedly in species are found. having very weak to absent pegs. (Figs. 7d, 19d, 23a—c,g, 25a,c-g, shell; 8d, Shell (Figs. 7d, 19d, 23a—c,g, 25a,c—g) with AUSTRALIAN SPRING HYDROBIIDS 49 = d C f ¿IMM 9 e FIG. 25. Shells of Fonscochlea billakalina and F. variabilis form В. Fonscochlea billakalina: a,g. Billa Kalina springs, a, (759) (paratypes, AMS, C.152930); g, (763) (AMS, C.152964). c. Old Billa Kalina Spring (027) (paratype, AMS, C.152963). d,e. Francis Swamp, d, (721) (AMS, C.152966); e, (720) (AMS, C.152968). f. Fenced Spring, Billa Kalina (723) (AMS, C.152965). Fonscochlea variabilis form B: b. Hawker Springs (673) (AMS, C.152970). two forms present. One form (Figs. 23a—<,g, 25a,d,f,g) with shell similar to that of F. vari- abilis form В and 1.9-2.4mm in length; other form (Figs. 7d, 25c), restricted to spring at Old Billa Kalina Homestead ruin (027, 759), is similar to F. variabilis form A but is larger (2.8-3.2 mm long compared with 1.8- 2.8 mm). Overall mean shell length 2.60 mm (males) and 2.64 mm (females). Teleoconch whorls 2.30-3.38 (mean 2.75, male; 2.77, female), convexity ratio 0.03-0.24 (mean 0.15, male; 0.14, females). Measurement data in Table 19A. Operculum (Fig. 8d) with 0—5 (mean 1.40, males; 1.59, females) small pegs 0.02-0.14 mm (mean 0.07 mm) in height; calcareous area 0-0.33 mm (mean 0.13 mm) long. See Table 19A for measurement data. Radula, see Table 3 for data. Head-foot (Fig. 24c) as for species. Back- ground pigmentation of snout and tentacles dark grey to black. Anatomy (Fig. 27c, female genitalia) as for species. See Tables 19B-E for measurement data. Type material: holotype (Fig. 19d) (SAM, D.17911, stn 027); and paratypes (SAM, D.2034, 30; SAM, D.2035, 32; 759B, AMS, PONDER, HERSHLER & JENKINS 50 -B9IU09 “Y PUB вииехе/иа Y ‘!идемел ее!42095и0- ‘зэюэдз эцепбе jjews jo UONNqUISIG ‘92 “Old Zbl - 195 UY N Y AS. № S So q (HLNOS)” 3443 JAVI ATuo STIWUS- о PoTUOO “Je ATuo STIUS- > PUTTEXETITG “dP D WIOJ- 4 я UNOJ- A (HLYON) Y WIOJ- у этттаетлел ‘4 3443 34V i 000 0001 :1 $1055 a, “OS Ov o€ 02 os 0 AUSTRALIAN SPRING HYDROBIIDS 51 go FIG. 27. Female genitalia of species of Fonscochlea. a,d. Fonscochlea variabilis form A. The Bubbler Spring. d, detail of sperm sacs. b. Fonscochlea conica, Horse Spring East. c. Fonscochlea billakalina, Old Billa Kalina Spring. ag, albumen gland; bc, bursa copulatrix; cg, capsule gland; cv, coiled oviduct; go, oviduct opening; mcp, posterior limit of pallial cavity; sr, seminal receptacle; vc, ventral channel; vcp, posterior extension of ventral channel. Scale: 0.25mm. C.152891, 18; 759B, AMS, 0.152892, many; 026, AMS, 0.152893, many, С. 152995, 1, figured; 027, AMS, C.152894, many, C.152963, 1, figured; 759, AMS, C.152930, 1, figured). Dimensions of holotype: length 2.78 mm, width 1.68 mm, length of aperture 1.33 mm. Localities: South Western Springs: Billa Kalina Springs (026-027, 723A-D, 758C, 759A-C, 760, 761, 763A,B), Francis Swamp (717A,B, 720А-С, 721A-C), Strangways Springs (029, 030, 678A,B, 679A-C, 680). Shells from Welcome Bore/Spring (758) and Margaret Spring (722) might belong to this form (Fig. 26). | Remarks: The two shell forms seen in pop- ulations included in this taxon are, when ex- tremes are examined, readily distinguished. Intermediate specimens, however, do occur in some populations. The shell characters are virtually identical, in most populations, with those of F. variabilis form B but that taxon can be readily distin- guished by its strong opercular pegs. With discriminate analysis, using shell and opercu- lar measurements, this species is clearly dif- ferentiated from the other small aquatic taxa (Figs. 28, 29, 30; Table 8). This taxon is recognised as a species be- cause of the considerable differences be- tween its operculum and those of the other small aquatic taxa. The lack of obvious corre- lated shell or anatomical characters is, in this case, judged to be outweighed by the strongly diagnostic opercular characters. Discrimination of the small aquatic taxa (in- cluding the geographic forms) of Fonscochlea was tested using discriminate analysis on shell and opercular measurements. The re- sults showed that all groups could be discrim- inated using these data, 87% of the measured specimens (n=617) being correctly classi- 52 PONDER, HERSHLER & JENKINS -6 -4 -2 0 2 4 6 FIG. 28. Plot of group centroids, using first two canonical axes, obtained from discriminate analysis of populations of small aquatic species and forms of Fonscochlea using shell and opercular measurements. Males and females of each population are, for the purposes of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: SH, 27.96%; SW, 3.82%; AH, 59.38%; TW, 8.45%; OL, 75.41%; PH, 57.85%; PC, 5.26%; PN, 1.00%. Second (vertical) axis: SH, 18.18%; SW, 42.38%; АН, 5.27%; TW, 48.72%: OL, 14.38%; РН, 23.02%; PC, 72.13%; РМ, 54.37%. b, Е. billakalina; с, Е. conica; e, Е. variabilis form В; д, Е. variabilis form С; м, Е. variabilis form A; s, F. variabilis, small Blanche Cup form. AUSTRALIAN SPRING HYDROBIIDS 53 -3 0 2 4 6 FIG. 29. Plot of group centroids, using first and third canonical axes, obtained from discriminate analysis of populations of small aquatic species and forms of Fonscochlea using shell and opercular measurements. Males and females of each population are, for the purposes of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: SH, 27.96%; SW, 3.82%; AH, 59.38%; TW, 8.45%; OL, 75.41%; PH, 57.85%; PC, 5.26%; PN, 1.00%. Third (vertical) axis: SH, 14.76%; SW, 3.03%; AH, 13.22%; TW, 5.61%; OL, 1.30%; PH, 9.07%; PC, 0.39%; PN, 1.98%. b, F. billakalina; c, F. conica; e, F. variabilis form B; g, F. variabilis form C; v, F. variabilis form A; s, F. variabilis, small Blanche Cup form. fied. The Euclidian (taxonomic) distances be- tween the groups are given in Table 8. The greatest distance score achieved between all pairwise comparisons was 3.95, between the small Blanche Cup form of F. variabilis and F. variabilis form B. Differences between the species was >1 in all cases except between F. variabilis form A and F. conica (score >0.69). F. conica separated from the other forms of F. variabilis with scores >1.1. F. bil- lakalina had a distance score of > 1.58 when compared with all other groups. Within F. vari- 54 PONDER, HERSHLER & JENKINS "5 -3 =] FIG. 30. Plot of group centroids, using second and third canonical axes, obtained from discriminate analysis of populations of small aquatic species and forms of Fonscochlea using shell and opercular measurements. Males and females of each population are, for the purposes of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: second (horizontal) axis: SH, 18.18%; SW, 42.38%; AH, 5.27%; TW, 48.72%; OL, 14.38%; PH, 23.02%; PC, 72.13%; PN, 54.37%. Third (vertical) axis: SH, 14.76%; SW, 3.03%; AH, 13.22%; TW, 5.61%; OL, 1.30%; PH, 9.07%; PC, 0.39%; PN, 1.98%. b, Е. billakalina; с, Е. conica; e, Е. variabilis form В; g, Е. variabilis form С; у, Е. variabilis form А; $, Е. variabilis, small Blanche Cup form. abilis the scores separating the forms were >0.44, the lowest scores being achieved be- tween forms B and C (0.44 females, 0.50 males), the comparisons between the other forms being > 1. SNK tests (5% level) using pooled data, combined and separate sexes, for each vari- able used in the discriminate analyses gave the following results: SH—Combined sexes: significantly differ- AUSTRALIAN SPRING HYDROBIIDS 55 ent for all except F. variabilis form С and F. variabilis form B. Separate sexes: only the small Blanche Cup form of F. variabilis and F. conica were clearly distinct, the others form- ing overlapping subsets. The means for this character were significantly different between males and females for all species and forms (females larger) except the small Blanche Cup form and F. billakalina. SW—Combined sexes: all means signifi- cantly different. Separate sexes: the small Blanche Cup form, F. conica and F. variabilis form A all form separate subgroups but the others are included in overlapping subgroups. All except the small Blanche Cup form are sexually dimorphic (females larger), the means in all cases being significantly differ- ent. AH—Combined sexes: significantly differ- ent for all species and forms except F. vari- abilis form В and F. billakalina. Separate sexes: same results as for SH. TW—Combined sexes: significantly differ- ent for all except F. variabilis form A + F. billakalina and F. variabilis form C + F. vari- abilis form B. Separate sexes: the small Blanche Cup form is distinctly different but all other groups, except males of F. conica, form overlapping subsets. This character does not significantly differ between males and fe- males except in F. conica. OL—Sexes combined: same result as AH. Separate sexes: the small Blanche Cup form and F. conica formed distinct groups as did males of Е. variabilis form A and females of F. variabilis form C. All other groups formed overlapping subsets. Differences between the sexes in this character were statistically sig- nificant in F. conica, F. variabilis form A, F. variabilis form C and F. variabilis form B. PH—Combined sexes: significantly differ- ent for all except F. conica and F. variabilis form B, and F. variabilis form A and F. vari- abilis form C. Separate sexes: all form over- lapping subsets except males of F. variabilis form C and F. variabilis form A which form their own group, as do the females of these two forms, these also being the only two groups to show significant sexual dimorphism in this character. PC—Combined sexes: all means signifi- cantly different. Separate sexes: the small Blanche Cup form and F. billakalina are not significantly different but all others are. Sex- ual dimorphism is exhibited in F. variabilis form B and F. variabilis form C. PN—Combined sexes: significantly differ- ent for all except the small Blanche Cup form and F. billakalina. Separate sexes: the same result but with F. variabilis form B and F. vari- abilis form C not discriminated. Only F. vari- abilis form B shows significant sexual dimor- phism in this character. Subgenus Wolfgangia n.subgen. Derivation: named for Wolfgang Zeidler (Fem.). Type species: F. (W.) zeidleri n.sp. Diagnosis: Shell (Figs. 6e-h, 7a,b, 14a,c, 53a,d) as for genus; differs from Fonscochlea 5.5. in being rather thick-shelled, aperture with thickened peristome and protoconch mi- crosculpture consisting of spiral lines (Fig. 9c,d). Operculum (Fig. 8a,b) with prominent pegs. Radula (Fig. 10a,b) as for genus. Central teeth always with two pairs of basal cusps. Head-foot (Fig. 11a,b) with cephalic tenta- cles about same length as snout or slightly shorter. Anatomy: Female genital system (Figs. 12a,b, 47) as for genus except oviduct be- tween capsule gland and bursal duct always straight and sperm sacs lie dorsal to muscular oviduct. Ducts of sperm sacs ventral to sacs. Male (Fig. 46b, penis) system as for genus. Remarks: The species included in this sub- genus can be divided into two morphologi- cally similar forms, one of which is amphibi- ous and the other aquatic. The amphibious form is the most widely distributed of the mound-spring snails; the other, one of the most restricted, is confined to a single spring. The differences in the protoconch micro- sculpture, and in the female genital tract, to- gether with the relatively larger snout and shorter tentacles possessed by F. (W.) zeid- leri, are characters that separate this species from the remainder of those in the genus. This species does, however, possess several key features in common with species of Fons- cochlea s.s., the equal-sized sperm sacs be- ing the most outstanding. For this reason, and because there do not appear to be any inter- grading states represented in any of the known species, F. (W.) zeidleri is judged to be subgenerically separable from Fonscochlea. This subgenus and its type species are named for Wolfgang Zeidler of the South Aus- tralian Museum, Adelaide, who first intro- duced the senior author to the mound springs and since then has assisted with this project in many ways. 56 PONDER, HERSHLER & JENKINS Fonscochlea (Wolfgangia) zeidleri n.sp. Diagnosis: As for subgenus description. The typical form of this species is described below as “form A” where a holotype is des- ignated for the species. Localities: Oodnadatta Complex, Northern, Middle, Western and Southern Springs (Fig. 31). Remarks: The characters separating the subgenus Wolfgangia from species of Fons- cochlea s.s. also serve to separate this spe- cies. The shell of this species is similar to that of the two large aquatic species of Fonscoch- lea, F. accepta and F. aquatica, in size and shape but can be distinguished by its thicker peristome, with the inner lip separated from the parietal wall, and its more convex whorls. Two geographic forms are recognised and additional details are given under the descrip- tions of each of them. Fonscochlea (Wolfgangia) zeidleri form A. (Figs. 6e-h, 7a, 14a, 53a,d, shell; 9c,d, pro- toconch; 8b, operculum; 10b, radula; 11a,b, head-foot; 12b, 47, female genitalia; 46b, pe- nis; 45, stomach) Diagnosis: Shell large for genus, up to about 5.3 mm long, solid, width/length ratio 0.55-0.7 (usually 0.6—0.65) with 3—4.4 con- vex (convexity ratio 0.04—0.26; mean 0.16, males; 0.18, females) teleoconch whorls sculptured with distinct growth lines and, in some specimens, faint spiral scratches. Pro- toconch microsculpture (Fig. 9c,d) of fine, closely-spaced, irregular spiral lines. Aperture with thickened peristome, inner lip thickened and separated from parietal wall; outer lip or- thocline to opisthocline, edge blunt. Colour yellowish brown to purplish brown. Opercu- lum thick, with prominent pegs. Shell (Figs. 6e-h, 7a, 14a, 53a,d; 9c,d, pro- toconch microsculpture), see diagnosis. See Table 20A for measurement data. Operculum (Fig. 8b) thick, with 2-6 (mean 4.02) heavy opercular pegs. See Table 20A for measurement data. Radula (Fig. 10b) as for subgenus. See Ta- ble 3 for data. Head-foot (Fig. 11a,b) variable in degree of pigmentation; snout long and mobile, with well-developed concentric ridges. Cephalic tentacles tapering, about same length as snout or slightly shorter. Usually an unpig- mented area around eyes; tentacles, in some populations, very pale and, in others, dark grey or black. Anatomy (Fig. 12b, 47, female genitalia; 46b, penis; 45, stomach) as described for subgenus. See Tables 20B-E for measure- ments. Type material: holotype (Fig. 14a) (SAM, D.17915, stn 764C); and paratypes (SAM, D.3206, 61; 764A, AMS, C.152889, 13; 764C, AMS, C.152900, many; 020, AMS, C.152901, 20; 021, AMS, C.152902, many; 022, AMS, C.152903, many; 023, AMS, C.152904, many; 019, AMS, C.152928, 6). Dimensions of holotype: length 4.82 mm, width 2.87 mm, length of aperture 1.85 mm. Localities: Southern Springs: Welcome Springs (754A, 755A,B,D; 756, shells only), Hermit Hill Springs (711A,B, 712), Old Finniss Springs (693A, 694B,C), Old Woman Springs (732, 733), Finniss Swamp West (690A,C). Shells have been collected from Priscilla Spring (686), Venable Spring (687) and an unnamed spring in Lake Eyre South (702). Middle Springs: Horse Springs West (746A,B), Horse Springs East (748B,C), Mt. Hamilton Homestead ruins (006, 749), Strangways Spring (007, 745A), Blanche Cup Spring (008-012, 685), Bubbler Spring (013-— 017), Little Bubbler Spring (744), unnamed springs, Blanche Cup Group (785, 786, 787), Coward Springs (019-023, 764A-C), Cow- ard Springs Railway Bore (018, 684, 743), Kewson Hill Springs (740A, 741, 742A), Julie Springs (772A-D, 773A-C), Elizabeth Springs (024, 766A-G, 767, 771A-C), Jersey Springs (025, 683A,B; 768, shells only; 769A,B, 770A-C), Warburton Springs (681 A- C, 682), Beresford Spring (028). Fossil shells have been collected from the top of Hamilton Hill. South Western Springs: Billa Kalina Springs (026, 027, 723A,C,D; 759, shells only; 760, 763A,B), Francis Swamp (717В, 720A,B, 721B,C), Strangways Springs (029— 030, 678A,B, 679A-C, 680). Shells from Mar- garet Spring (722) and Welcome Bore (758). Northern Springs: Brinkley Spring (677), Hawker Springs (670A-C, 671, 672C,D, 673), Big Perry Springs (034), Twelve Mile Spring (036, 037), Outside Springs (039). Shells from Spring Hill Springs (674). Freeling Springs (043, 046, 664A-C, 665A-C). Remarks: This form, the most widely dis- tributed of the mound-spring snails, is of spe- cial interest because of its amphibious habit. К lives, in most springs, along the edges of 57 AUSTRALIAN SPRING HYDROBIIDS Zbl - 135 as Y NY U | ATuo STISUS- У TASTPIOZ ‘A y 000 0001: 1 #1055 осо "y WO} H8/PI8Z BajYIOISUO JO UONAQUISIO “LE “Ola < (HLNOS)“ 3443 IVT Sr dwems EX SIOUBIZ (HLYON) JAI JAVI N uosiuag WwW / v — 58 PONDER, HERSHLER & JENKINS the outflows where it is either exposed, as on the hard substrates found on the calcareous mounds, or partly or completely buried in the sediment. The preference for burrowing in the substrate appears to differ between spring groups and might not be due entirely to sub- strate differences. For example the popula- tions of this species at Hermit Hill are ex- tremely cryptic, mainly because of this habit, whereas at Welcome Springs, with similar substrate available, they are much more con- spicuous, large numbers being present on the surface. Populations at Kewson Hill and Elizabeth Springs have two recognisable phenotypes. One is the typical shell form (Fig. 53d) indis- tinguishable from specimens found else- where. Another form (Fig. 53a) is shorter, darker, relatively broader, and with a relatively larger aperture than the typical form. These two forms have been found living together but usually occupying different microhabitats. The typical form is found along the edges of the outflow and around the head of the spring or seepage, the normal habitat for this species, whereas the squat form is invariably found in the outflows where it lives attached to any available emergent substrate, usually in very large numbers. Some individuals are found in the water but most are out of it. Some other populations (e.g., Blanche Cup and Horse Springs East) contain many intermediates be- tween these two types (Fig. 6e—h). Fonscochlea (Wolfgangia) zeidleri form B. (Figs. 7b, 14c, shell; 8a, operculum; 10a, rad- ula; 12a, female genitalia) Diagnosis: Shell smaller than typical spec- imens of F. (W.) zeidleri form A (up to 4.06 mm long) and with relatively broader (shell width/shell length 0.63-0.65) than many pop- ulations of F. (W.) zeidleri form A. 2.9-3.5 convex (convexity ratio 0.14-0.22) teleo- conch whorls. Aperture with orthocline outer lip. Value of aperture length/shell length sig- nificantly larger than in most populations of F. (W.) zeidleri form A. Colour dark brown. Shell (Figs. 7b, 14c), see diagnosis. See Ta- ble 20A for measurement data. Operculum (Fig. 8a) with 2-6 (mean 3.85, males; 3.4, females) prominent opercular pegs. See Table 20A for measurement data. Radula (Fig. 10a) as for subgenus. See Ta- ble 3 for data. Head-foot similar to that of F. (W.) zeidleri form A but, in most specimens, weakly pig- mented except for large patch of black pig- ment behind eyes. Snout and cephalic tenta- cles lack pigment in some specimens but in a few are darkly pigmented. Anatomy (Fig. 12a, female genitalia) as de- scribed for subgenus. See Tables 20B-E for measurements. Voucher material: primary voucher speci- men (Fig. 14c) (SAM, D.17916, stn 661); and material from the same population (661, SAM, D.17945, many; AMS, C.152905, many, C.152993, 1, figured). Dimensions of primary voucher specimen: length 4.04 mm, width 2.56 mm, length of ap- erture 1.72 mm. This is one of the largest specimens of this form. Locality: Oodnadatta Spring Complex: Big Cadnaowie Spring (661). Remarks: This population is distinguished as a separate form, despite few morphologi- cal differences, because it is considerably geographically isolated, has a distinctive shell shape (although duplicated in a few examples of F. (W.) zeidleri form A) and its fully aquatic habit is a considerable departure from the amphibious habit of the typical form. The lack of significant morphological differentiation suggests that it is probably only recently de- rived from F. (W.) zeidleri form A. The populations of F. (W.) zeidleri form A that develop squat shells with width/length ra- tios similar to those of F. (W.) zeidleri form B are virtually all associated with harsh environ- ments, e.g., the Kewson Hill Springs (Fig. 53a). The conditions that appear to bring about the shortening of the shell in F. (W.) zeidleri form A, small, shallow outflows and hard substrate, are not those in which F. (W.) ‚ zeidleri form В is found. This form lives in a large, degraded spring in a few metres of sedges in a narrow, outflow with a significant flow of water. It is completely aquatic and very abundant in this part of the habitat. A very few individuals were found in the remainder of the spring, which has been severely damaged by livestock. This spring has since been fenced as part of the mound-spring fencing pro- gramme, mainly because of the reported ex- istence of this unusual population (Ponder & Hershler, 1984). Discrimination of the two forms of Fonscoch- lea zeidleri was tested using discriminate analysis on a subset of shell measurements. AUSTRALIAN SPRING HYDROBIIDS 59 -1 -2 -3 -1 1 3 FIG. 32. Plot of group centroids, using first two canonical axes, obtained from discriminate analysis of populations of Fonscochlea zeidleri using shell measurements. Males and females of each population are, for the purposes of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: SH, 82.65%; SW, 0.29%; AH, 69.38%; TW, 18.79%. Second (vertical) axis: SH, 2.19%; SW, 55.66%; AH, 21.12%; TW, 47.45%. Closed circles, F. zeidleri form A; open circles, F. zeidleri form B. The results (Fig. 32) showed that both groups could be discriminated using these data, 92% of the measured specimens (n=284) being correctly classified. SNK tests (5% level) using pooled data, combined and separate sexes, for each vari- able used in the discriminate analyses gave the following results: SH, AH and TW were significantly different for combined sexes of both forms. No char- acters separated the two forms using separate male and female data. Sexual dimorphism was apparent only in TW for both forms. Genus Trochidrobia n.gen. Derivation: Trochi (Latin), a child’s hoop, and used for a genus of gastropods (Tro- chus), pertaining to the shape of the shell; drobia, from Hydrobia, the type genus of Hy- drobiidae (fem.). Type species: Trochidrobia punicea n.sp. Distribution: Artesian springs between Mar- ree and Oodnadatta, northern South Austra- lia. Diagnosis: Shell (Figs. 33, 37) of known species small (as much as 2mm in dia- meter), trochiform to depressed-trochiform, umbilicate, smooth, with only sculpture weak axial growth lines. Protoconch (Fig. 34) of about one and one-half whorls, sculptured with irregular minute pits, or pits and spiral threads. Aperture oval, peristome thin, no ex- ternal varix; outer lip simple, not expanded or flared, with thin edge. Periostracum smooth, thin. 60 PONDER, HERSHLER & JENKINS FIG. 33. Shells of Trochidrobia. a-c. Trochidrobia punicea, holotype. Blanche Cup Spring (009). d-f. Trochidrobia smithi, holotype. Twelve Mile Spring (036). Operculum (Fig. 35a,c,e,f) corneous, oval, nucleus subcentral, thin, simple. Radula (Fig. 35b,d) with central teeth um, lateral teeth 3-6+ 1+4-7, inner marginal teeth with 18-31 formula cusps, outer marginal teeth with many small cusps. Head-foot (Fig. 24h) with cephalic tenta- cles longer than snout, parallel sided, in- conspicuously ciliated ventrally. Pigmenta- tion usually dense, pigment granules black AUSTRALIAN SPRING HYDROBIIDS 61 FIG. 34. Protoconchs of species of Trochidrobia. a,b. Trochidrobia punicea, Coward Springs (020). c,d. Trochidrobia smithi, The Fountain Spring (032). e,g. Trochidrobia minuta, Freeling Springs (045). f. Trochidrobia inflata, Freeling Springs (043). Scale: а,с,1,9 = 0.1тт; b,d,e = 0.01mm. and white. General head-foot typical of half to one-third length of ctenidium, its роз- family. terior extremity situated near posterior end of Anatomy: pallial cavity (Fig. 48) with well- ctenidium. developed ctenidium; osphradium oval, about Female reproductive system (Figs. 36, 38) 2-4 times as long as broad and about one- with single sperm sac and coiled oviduct Iying 62 PONDER, HERSHLER & JENKINS FIG. 35. Radulae and opercula of Trochidrobia. a. Operculum of Trochidrobia punicea, Blanche Cup Spring (008). b. Radula of Trochidrobia punicea, Welcome Springs (002). c. Operculum of Trochidrobia inflata, Freeling Springs (043). d. Radula of Trochidrobia smithi, Old Billa Kalina Spring (027). e. Operculum of Trochidrobia smithi, Old Billa Kalina Spring (027). f. Operculum of Trochidrobia minuta, Freeling Springs (045). Scale: a,c,d,e = 0.1mm; b,d = 0.01mm. AUSTRALIAN SPRING HYDROBIIDS 63 FIG. 36. Female genitalia of species of Trochidrobia. a. Trochidrobia smithi. Outside Springs (039). b. Trochidrobia punicea. Strangways Spring, E. of Blanche Cup (007). ag, albumen gland; bc, bursa copulatrix; cg, capsule gland; co, coiled part of oviduct; go, oviduct opening; int, intestine; mcp, posterior limit of pallial cavity; r, rectum; st, tissue connection between oviduct and pericardium; uo, upper oviduct; vc, ventral channel. Scale: 0.1тт. 64 PONDER, HERSHLER & JENKINS on inner (left) side of albumen gland or mainly situated behind this gland. Coiled part of ovi- duct an unpigmented tube Iying largely in front of large bursa copulatrix. Bursa copula- trix about one-third to one-half of length of albumen gland, its narrow duct opens to ovi- duct in different locations depending on spe- cies. Gonopericardial duct absent but repre- sented by strand of tissue. Oviduct straight anterior to point of opening of bursal duct. Ac- cessory sperm storage occurs in swollen part of posterior ventral channel of capsule gland or in coiled oviduct. Capsule gland about same length as albumen gland to about half its length, with a well-developed ventral chan- nel containing ciliated lateral fold. Genital pore terminal, subterminal or placed at about one-third of distance along capsule gland. Egg capsules spherical, cemented in umbili- cus of shell with mucus (Known only in T. pu- nicea). Male reproductive system with vas defer- ens complexly coiled beneath anterior part of testis. Pallial and visceral vas deferens enter and leave prostate gland in middle section. Prostate gland extends into pallial wall one- third to one-half of its length. Pallial vas def- erens a narrow, Straight, ciliated tube lying just beneath epithelium on right side of pallial floor but undulates as it passes up right side of neck to enter base of penis. Penis (Fig. 49) with swollen basal portion and tapering distal portion. Basal part unpigmented, concentri- cally creased and narrow penial duct undu- lates within it. Distal portion smooth, usually pigmented, coiled anti-clockwise when at rest, penial duct straight within it, emerging at pointed distal extremity. Alimentary canal typical of family; buccal mass well developed with U-shaped radular sac protruding behind. Salivary glands sim- ple, tubular. Stomach (Fig. 44a) with distinct anterior and posterior chambers, anterior one larger, lacks caecal appendage. Style sac contains crystalline style, comprises about one-third to one-half of total length of stom- ach. Single digestive gland opening immedi- ately posterior to oesophageal opening. Di- gestive gland covers inside of right side of stomach to about halfway across anterior chamber. Intestine makes U-shaped fold on pallial roof in one species. Nervous system with left pleural and sub- oesophageal ganglia abutting and right pleu- ral and supra-oesophageal ganglion sepa- rated by long connective. See anatomical account for further detail. Remarks: The species contained in Tro- chidrobia are similar in shell and opercular characters to those in the European Horatia- Pseudamnicola complex but differ in several important character states. These include the lack of a seminal receptacle (not one or two); a longer, coiled oviduct; two pairs of basal cusps on the central teeth of the radula (not a single pair); a penis having a slender, simple distal portion longer than the basal part (not shorter than the base); and the left pleural and suboesophageal ganglia abutting (not separated by a connective) (see Radoman, 1966, 1983, for further detail regarding the European taxa). Some species in the Beddomeia complex in Tasmania, particularly Valvatasma tasma- nica (T. Woods, 1876), are similar to species of Trochidrobia in shell form. They differ, how- ever, in having an operculum with an eccen- tric nucleus and a radula with a single pair of basal cusps. All of the species in the Bed- domeia complex have a seminal receptacle. Another species similar to the Beddomeia group is Jardaniella thaanumi (Pilsbry, 1900), from north Queensland. This species has two pairs of basal cusps on the radula, an eccen- tric opercular nucleus and a seminal recepta- cle (all data on Beddomeia group from Pon- der, unpublished). Heterocyclus petiti (Crosse, 1872) from New Caledonia has a depressed, umbilicate shell but the outer lip is flared and the calcar- eous, multispiral operculum is of different construction (Starmülner, 1970). It is unlikely that this species is even remotely related. The only other Australian genus of de- pressed shell form is Posticobia, which is re- lated to Hemistomia (see Ponder, 1981). Hor- atia nelsonensis Climo, 1977, from Nelson, New Zealand, is known only from shells but it is probable that this species is a depressed form of Opacinacola, a New Zealand genus normally having higher-spired shells. Trochidrobia punicea n.sp. Derivation: puniceus (Latin) purple, red. A reference to the dark purple-red colour of the shell of living specimens. (Figs. 33a—, shell; 34a,b, protoconch; 35a, operculum; 35b, radula; 24h, head-foot; 48, pallial cavity; 44a, stomach; 36b, female gen- ital system; 49a, penis) AUSTRALIAN SPRING HYDROBIIDS 65 Diagnosis: Shell up to 2.22 mm in diameter, depressed (width/height ratio 1.1-1.3), with 1.50-2.25 convex whorls and widely umbili- cate. Protoconch microsculpture (Fig. 34a,b) of close spiral ridges with irregular surface pit- ting over the entire surface. Aperture some- times separated from parietal wall. Colour yel- lowish brown to dark orange-brown. Female genitalia with very much thickened coiled ovi- duct, long bursal duct and simple ventral channel. Rectal arch absent in male (rectum lies alongside prostate gland). Shell (Fig. 33a—c), see diagnosis. See Ta- ble 21A for measurement data. Operculum (Fig. 35a) as for genus. Radula (Fig. 35b) as for genus. See Table 3 for data. Head-foot (Fig. 24h) variably pigmented, dark pigmentation common, usually with nar- row dorsal unpigmented stripe on proximal half of tentacles continuous with unpigmented zone around eyes. Anatomy (Figs. 48, pallial cavity; 44a, stom- ach; 36b, female genital system; 49a, penis), see anatomical section below for full descrip- tion. See Tables 21B-C for measurement data. Type material: holotype (Fig. 33a—c) (SAM, D.17922, stn 009); and paratypes (008, SAM, D.3208, 58; SAM, D.2030, 60; 739, AMS, C.152906, many; 009, AMS, C. 152907, many; 008, AMS, C.152908, many; 010, AMS, C.152909, many; 011, AMS, C.152910, 20; 012, AMS, C.152911, 10). Dimensions of holotype: length 1.62 mm, width 2.08 mm, length of aperture 1.08 mm. Localities: Southern Springs: Welcome Springs (002, 003, 754A-D, 755A-D, 756A- C), Davenport Springs (005, 752A-C, 753A,B), Hermit Hill Springs (712), Dead Boy Springs (689), Finniss Swamp West (690A- С, 691), Bopeechee Springs (692A,B), Old Finniss Springs (693A-C, 694A-C, 710), Old Woman Spring (733A-E), Sulphuric Springs (735, 737). Shells from Priscilla Spring (686), Venable Spring (687). Middle Springs: Horse Springs East (747A,B, 748A-C), Horse Springs West (746A), Mt. Hamilton Homestead ruins (749), Strangways Springs (007,745A,B), Blanche Cup Spring (008-012, 739), Bubbler Spring (013-017), Little Bubbler Spring (744A-C), an unnamed spring, Blanche Cup Group (785, 786, 787), Coward Springs (019-022, 023, 764A-C), Kewson Hill Springs (741, 742B, 765), Julie Springs (772A-D, 773A-C), Jersey Springs (025, 768A, 769A,B, 770A,B), Elizabeth Springs (024, 766A-E, 767A,B, 771A,B) (Fig. 39). Fossil shells similar to this species have been collected from travertine on the top of Hamilton Hill. Remarks: The shell of this species is virtu- ally identical to that of T. smithi described be- low, the only characters, apart from proto- conch microsculpture (which has been examined in only a few specimens), distin- guishing these two species being anatomical ones. See under T. smithi for details. Both of these species are extremely abun- dant in most of the springs in which they oc- cur. They live in a variety of microhabitats and appear to be particularly abundant in shallow, firm-bottomed outflows. They are positively phototropic, living fully exposed in the out- flows. See physiology section below for more details. Trochidrobia smithi n.sp. Derivation: named for Dr. B.J. Smith. (Figs. 33d-f, shell; 34c,d, protoconch; 35e, operculum; 35d, radula; 36a, female genitalia; 49b, penis) Diagnosis: Shell and head-foot virtually identical to those of T. punicea, maximum width of shell 2.13 mm, with 1.63-2.13 (mean 1.92) teleoconch whorls. Protoconch micro- sculpture (Fig. 34d) of spirally arranged wrin- kles, weaker than spiral sculpture of T. puni- cea. Female genitalia with narrow coiled oviduct and expanded posterior part of ventral channel (Fig. 36a). Rectal arch present in male (rectum separated from prostate gland). Shell (Figs. 33d-f; 34c,d, protoconch, see diagnosis. See Table 21A for measurements. Operculum (Fig. 35e) as for genus. Radula (Fig. 35d) as for genus. See Table 3 for data. Head-foot very similar to that of T. punicea, variably pigmented, uniformly dark pigmenta- tion being common. Anatomy (Figs. 36a, female genitalia; 49b, penis) very similar to that of 7. punicea; see diagnosis for differentiating characters. See Tables 21B-C for measurements. Type material: holotype (Fig. 33d-f) (SAM, D.17923, stn 036); and paratypes (SAM, D.2028, 5; 037, AMS, C.152912, many; 036, AMS, C.152913, many; 1003B, AMS, C.152915, many; 1003C, AMS, C.152916, many; 1003D, AMS, C.152917, many). 66 PONDER, HERSHLER & JENKINS Imm FIG. 37. Shells of species of Trochidrobia. a-c. Trochidrobia inflata, holotype. Freeling Springs (042). d-f. Trochidrobia minuta, holotype. Freeling Springs (046). Dimensions of holotype: length 1.31 mm, width 1.66 mm, length of aperture 0.78 mm. Localities: Middle Springs: Warburton Spring (681A-C, 682), Beresford Spring (028). South Western Springs: Billa Kalina Springs (026-027, 723A-D, 758C, 759A; 760, shells only; 761B, 762A,B, 763A,B), Francis Swamp (717A-C, 720A-B, 721A-C), Margaret Spring (722, shells only), Strang- — ways Springs (029-030, 678A,B, 679А-С). Northern Springs: Brinkley Springs (677), Hawker Springs (670A-C, 671, 672A-D, 673), Fountain Spring (031-033), Twelve Mile Spring (035-037, 1003B-C) Outside Springs (038-040), Big Perry Spring (034) (Fig. 39). Remarks: Although this species is virtually identical to T. punicea in shell characters, it can be immediately recognised on dissection, the female genitalia being readily distin- guished from those of T. punicea in having a markedly narrower coiled oviduct and in the posterior part of the ventral channel being ex- panded and, in males, in having a prominent rectal arch. The ecology of this species ap- pears to be very similar to that of T. punicea. Discriminate analysis, using only shell measurements, achieved some separation of T. punicea and T. smithi (Figs. 40, 41; Table 9). A clear separation was achieved with fe- male genital measurements (Fig. 42; Table 9). This species is named for Dr. B. J. Smith, formerly of the Museum of Victoria, Mel- bourne, as a small mark of appreciation of his contributions to the study of Australian non- marine molluscs. Trochidrobia minuta n.sp. Derivation: a reference to the small size of this species. (Figs. 37d-f, shell; 34e,g, protoconch; 35f, operculum; 38b, female genitalia) Diagnosis: Shell very small (up to about 1.2 mm in diameter), very depressed (width/ height ratio 1.5-1.6), with 1.25-1.5 (mean 1.47, males; 1.43, females) weakly convex whorls and widely umbilicate. Protoconch sculptured with irregular wrinkles and pits not arranged spirally (Fig. 34e,g). Colour yellow- ish white to pale brown. Head-foot darkly pig- AUSTRALIAN SPRING HYDROBIIDS 67 FIG. 38. Female genitalia of species of Trochidrobia. a. Trochidrobia inflata, Freeling Springs. b. Trochidrobia minuta, Freeling Springs. ag, albumen gland; bc bursa copulatrix; cg, capsule gland; co, coiled part of oviduct; go, oviduct opening; int, intestine; mcp, posterior limit of pallial cavity; r, rectum; vc, ventral channel; vcp, posterior extension of ventral channel. Scale: 0. 1тт mented. Female genitalia with bursa copulatrix placed largely behind albumen gland (in other species it lies alongside albu- men gland). Coiled oviduct narrow, short, and ventral channel simple. Shell (Figs. 37d-f; 34e,g, protoconch), see diagnosis. See Table 21A for measurement data. Operculum (Fig. 35f) as for genus. Radula as for genus. See Table 3 for data. Head-foot with darkly pigmented snout and grey triangular zone posterior to eyes. Very narrow unpigmented zone around eyes. Cephalic tentacles pale grey, unpigmented distally, without median line. Anatomy (Fig. 38b, female genitalia), as for 68 PONDER, HERSHLER & JENKINS genus. See diagnosis for differentiating char- acters. See Table 21B-C for measurement data. Type material: holotype (Fig. 37d-f) (SAM, D.17924, stn 046); and paratypes (045, AMS, C.152918, many; 664A1, AMS, C.152919, 2; 664A2, AMS, C.152920, 29; 046, AMS, C.152921, many). Dimensions of holotype: length 0.72 mm, width 1.11 mm, length of aperture 0.50 mm. Localities (Fig. 39): Northern Springs: Fountain Spring (031-032, 1002), Big Perry Springs (034,1001), Outside Springs (1006), Twelve Mile Spring (1003). Freeling Springs (043, 045, 046, 663, 664), unnamed spring north of Freeling Springs (666). Remarks: This minute species is very dis- tinctive and is readily separable on shell char- acters from T. punicea and T. smithi, although small individuals of those species approach it in size. Apart from most shell dimensions, the shell ratios PD/SH and SW/SH are signifi- cantly different in populations of T. minuta when compared with T. smithi and T. punicea. The flat spire and pale colour are particularly characteristic. Discriminate analysis (Figs. 40, 41, shell; 42, female genital anatomy; Ta- ble 9) readily distinguished this species from congeners. This species is abundant in the upper and middle parts of the spring outflows at Freeling Springs, but appears to be less common in the Northern Springs. The occurrence of this spe- cies together with T. smithi in some of the Northern Springs is of interest because the size difference between these species is not so marked as it is between all other sympatric congeners in the mound springs. It would be of interest to compare the interactions between these two species with those between T. minuta and T. inflata, which show greater size differences. Trochidrobia inflata n.sp. Derivation: a reference to the inflated shell of this species. (Figs. 37a—c, shell; 34f, protoconch; 35c, operculum; 38a, female genitalia) Diagnosis: Shell up to 1.72 mm in diameter, with rather high spire (width/height ratio about 1), 1.38-2.13 (mean 1.94, males; 1.95, fe- males) convex whorls, and narrowly umbili- cate. Protoconch microsculpture (Fig. 34f) of spirally arranged pits and wrinkles. Colour brown. Female genitalia similar to those of T. smithi but lacking expansion of ventral chan- nel. Shell (Fig. 37а—с), see diagnosis. See Ta- ble 21A for measurement data. Operculum (Fig. 35c) as for genus. Radula as for genus. See Table 3 for data. Head-foot darkly pigmented, dark grey to black, with rather narrow unpigmented zone around eyes and very narrow median unpig- mented line on cephalic tentacles in some specimens, sometimes margined with black lines. Anatomy (Fig. 38a, female genitalia) as for genus. See diagnosis for differentiating char- acters. See Table 21B-C for measure- ments. Type material: holotype (Fig. 37a—c) (SAM, D.17925, stn 042); and paratypes (042, AMS, C.152922, many; 043, AMS, C.152923, many; 044, AMS, C.152924, many; 663, AMS, C.152925, 4). Dimensions of holotype: length 1.58 mm, width 1.61 mm, length of aperture 0.88 mm. Localities: Freeling Springs (042—046, 663, 664B,C, 665A-C) (Fig. 39). Remarks: The small umbilicus and relatively high spire enable this species to be readily distinguished. It is particularly abundant in the lower parts of the spring outflows and is sym- patric with 7. minuta. These two species differ significantly in size and in the values of shell ratios PD/SH, SW/SH and AH/SH. Discrimination of all of the taxa of Tro- chidrobia was tested using discriminate ana- lysis of measurements of shell and female genitalia. With the shell measurements 76% of the measured individuals (n=219) were correctly classified (combined sexes) (Figs. 40, 41). With female genital measurements (Fig. 42) 88% of all measured individuals (n= 26) were correctly classified. The gener- alized (taxonomic) distances between the groups are given in Table 9. Using shell mea- surements the greatest distance score achieved with pairwise comparisons between the species was 1.4 (the comparison between T. minuta and T. smithi; males 1.41, females 1.46), the lowest 0.12 (between females of T. smithi and T. punicea). With female genitalia the highest score (4.3) was achieved between T. minuta and T. punicea, with the compari- son between T. punicea and T. smithi being 2.64. The lowest score (0.74) was between T. smithi and T. inflata. 69 AUSTRALIAN SPRING HYDROBIIDS ‘BIGOIPIYOLL JO Saldads ay) JO иоцпаще!а 6€ “DIA Zbl - 195 Sy AL ER Ss (HLNOSI” 3YA3 IVT PES о \ № 2 u dwems A EM SIOUBIZ езетзит * L A equ “LL e ATUO STIEUS - TUYIUS 'L oa TYFTUS ° m ATuo sTTeys - eeotund 'L y (HLYON) ` eootund “L т ) JYAJ AVI 000 0001 :1 #1055 qe рии K wos Ov og 02 осо \ 70 PONDER, HERSHLER & JENKINS -8 -6 -4 =2 0 2 4 6 FIG. 40. Plot of group centroids, using first two canonical axes, obtained from discriminate analysis of populations of species of Trochidrobia using shell measurements. Males and females of each population are, for the purpose of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: SH, 88.75%; SW, 59.20%; AH, 89.98%; AW, 91.18%, BW, 81.96%; TW, 0.56%; PD, 11.13%. Second (vertical) axis: SH, 2.72%; SW, 19.12%; AH, 2.21%; AW, 1.31%; BW, 9.23%; TW, 2.27%; PD, 75.38%. i, Г. inflata; m, T. minuta; р, T. ритсеа; $, T. smithi. SNK tests (5% level) using pooled data, able used in the discriminate analyses gave combined and separate sexes, for each vari- the following results: AUSTRALIAN SPRING HYDROBIIDS TA 1 JAMES 6 4 2 0 2 a 6 FIG. 41. Plot of group centroids, using first and third canonical axes, obtained from discriminate analysis of populations of species of Trochidrobia using shell measurements. Males and females of each population are, for the purposes of this analysis, treated as distinct populations. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: SH, 88.75%; SW, 59.20%; AH, 89.98%; AW, 91.18%, BW, 81.96%; TW, 0.56%; PD, 11.13%. Third (vertical) axis: SH, 0.11%; SW, 0.34%; AH, 5.02%; AW, 5.01%; BW, 0.88%; TW, 93.46%; PD 0.02%. i, T. inflata; m, T. minuta; p, T. punicea; s, T. smithi. Shell characters: AW—Combined sexes: 7. minuta and SH—Combined and separate sexes: T. minuta significantly different from all other taxa, which form a single subgroup. There is no sexual dimorphism in this character. SW—Combined sexes: all means are sig- nificantly different. Separate sexes: three dis- crete subgroups are formed, T. minuta, T. in- flata + T. punicea male, and T. punicea female + T. smithi. T., punicea is the only species sexually dimorphic (females larger) in this character. AH—Combined and separated sexes: the only taxon significantly different from the oth- ers is T. minuta. There is no sexual dimor- phism in this character. T. smithi form two separate subgroups with an intermediate, separate group formed by the other two taxa. Separated sexes: dis- crete subsets are formed by 7. minuta, T. punicea (male) + T. inflata (male), and T. punicea female + T. inflata female + T. smithi. Thus significant sexual dimorphism is apparent in T. punicea and T. inflata in this character. BW, TW—Combined and separate sexes: only T. minuta is separated as a distinct sub- group. There is no sexual dimorphism appar- ent in these characters. PD—Combined sexes: two separate sub- groups, T. minuta + T. punicea, and T. smithi 72 PONDER, HERSHLER & JENKINS -6 -4 2 0 2 4 FIG. 42. Plot of discriminate scores for individuals, using first two canonical axes, obtained from discriminate analysis of specimens of Trochidrobia using female genital measurements. The axes contain the following percentages of the variance of the variables used: first (horizontal) axis: GO, 51.32%; CG, 61.65%; AG, 93.08%; BC, 52.76%; WB, 98.57%; DB, 90.61%; CV, 98.19%; DV, 95.13%. Second (vertical) axis: GO, 39.60%; СС, 37.93%; AG, 3.61%; BC, 43.64%; WB, 0.15%; DB,3.02%; CV, 1.25%; DV, 3.71%. i, T. inflata; m, T. minuta; р, T. punicea; $, T. smithi. AUSTRALIAN SPRING HYDROBIIDS 73 TABLE 9. Summary of results of discriminate analysis of species of Trochidrobia. The numbers are the Euclidean (taxonomic) distances between the groups. IE UE punicea smithi T. punicea X 0.128 0.271 T. smithi 0.155 x 2.646 T. minuta 1.306 1.437 4.301 1.675 T. inflata 0.243 0.324 3.377 0.744 Left side: Combined sexes, shell Female, genital and T. inflata. Separate sexes: these two groups are not discriminated, all means falling into overlapping subsets. Female genital characters: GO—T. minuta separated from the rest of the species. CG, AG—no distinct subgroups. BC, WB, DB, DV—T. punicea separated from the other species. CV—T. minuta and T. inflata form a sub- group and 7. smithi and T. punicea both sig- nificantly different. Anatomy Anatomical description of Fonscochlea ac- cepta: Head foot (Fig. 11d). The distally bi- lobed snout is slightly shorter than the narrow, parallel-sided tentacles. These tentacles move slowly up and down and are held at about 45° to the longitudinal axis of the snout. They are not ciliated dorsally and weakly cil- iated ventrally, the cilia beating backwards at right angles to the longitudinal axis of the ten- tacle. The tentacles have blunt, rounded ends and the conspicuous, black eyes are in bulges at their outer bases. The entire dorsal side of the snout and most of the head are black or grey, and the tentacles are usually grey with a narrow, pale, longitudinal mid- dorsal stripe. The eyes are surrounded by a rim of unpigmented epithelium and immedi- ately behind them is a triangular zone of black pigment. The inner sides of the proximal ends of the tentacles have scattered, minute, Opaque white spots, and poorly developed subepithelial pigment gives this area a slight reddish-brown tinge. There is an unpig- T: TE minuta inflata Right side: 1.383 0.239 Female, shell 1.149 0.219 Male, shell 1.462 0.274 1.414 0.385 X 1.356 1.142 1.248 X 0.999 mented or weakly pigmented, ciliated, narrow rejection tract running down each side of the head-foot, at the junction of the foot and the “neck”, to the sides of the foot. The tract on the right is more strongly developed in fe- males than in males. Metapodial and pallial tentacles are absent. The mantle collar has numerous black and a few white subepithelial pigment cells giving it a greyish appearance. The head-foot, by way of contrast, is pig- mented by epithelial cells. The foot is slightly expanded anteriorly, rather short (about two-thirds the shell length), about two and one-fourth times as long as it is wide, and has a prominent slit along the an- terior edge. The anterior mucous gland opens by way of this slit and can be seen dorsally through the unpigmented propodium. It is roughly triangular and composed of about 18 simple tubules that lie along the longitudinal axis of the foot. There is a slight lateral con- striction in the anterior third of the foot and it is rounded behind. The foot is pale grey to dark grey along the sides and posteriorly but the anterior end is unpigmented mid-dorsally. The sole is pale grey, this colour being imparted by scattered black pigment cells inthe connective tissue in the pedal haemocoel. Subepithelial gland cells make up the sole gland. The sole is ciliated, the cilia beating in a posterior di- rection. Cilial currents around the edges of the foot pass particles posteriorly. Mantle cavity (Fig. 4F). The mantle cavity is longer than broad and contains a well-devel- oped ctenidium (CT) with triangular filaments (see Table 18B) for statistical details), which extends through almost the entire length of the mantle cavity and occupies about half of the 74 PONDER, HERSHLER & JENKINS cgl FIG. 43. a. Stomach of Fonscochlea accepta form A, Welcome Springs, viewed from its inner (left) side. b. Circum-oesophageal ganglia of F. accepta form A, Welcome Springs viewed dorsally (pedal ganglia omitted). ac, anterior chamber of stomach; cgl, left cerebral ganglion; dgo, digestive gland opening; int, intestine; Ip, left pleural ganglion; os, oesophagus; pc, posterior chamber of stomach; ss, style зас; гр, right pleural ganglion; sbo, suboesophageal ganglion; spo, supra-oesophageal ganglion. Scale: 0.25mm. pallial roof in the posterior section, but narrows considerably anteriorly. An oval, unpigmented osphradium (OS) lies to the left of the posterior end of the ctenidium. It is about one-third the length of the ctenidium and consists of a raised, unciliated central portion containing the osphradial ganglion bordered by a slightly lower, weakly ciliated region with longer epi- thelial cells. Part of this border is separated from the central area by a narrow groove, forming a weak encircling ridge. A very poorly developed hypobranchial gland lies over the posterior end of the rectum. The mantle collar is ciliated, the cilia driving particles outwards. Alimentary system. A small pair of jaws composed of chitinous rodlets lies in the an- terior end of the buccal tube. The buccal mass occupies the length of the snout and the radular sac protrudes behind it. The free por- tion of this sac is about twice as long as the buccal mass. Two simple, tubular salivary glands open to the buccal cavity and lie dorsal to the nerve ring. The oesophagus is simple, narrow and the anterior part (mid-oesopha- gus) contains long dorsal folds that coil in a dorsal direction. The dorsal folds are lined with low ciliated cells but the lateral walls are predominantly lined with dark-blue-staining short cells which appear to be glandular. The stomach (Figs. 43a, 44b; see also Fig. 45, stomach of F. zeidleri) is typical of the family in having a style sac (ss), an anterior (ac) and a posterior chamber (pc), and a sin- gle, posterior, slit-like digestive gland opening (dgo). There is no caecal appendage. The style sac occupies about 0.6 of the stomach length and contains a crystalline style; the in- testine (int) opens to it along about two-thirds of its length. Externally the anterior and pos- terior chambers are distinguishable only on the inner (ventral) side and the oesophagus (os) and digestive gland open on this side. Internally the major typhlosole (t1) runs to the posterior end of the stomach and is subdi- vided into two low, strongly ciliated ridges (t1a,tib). The minor typhlosole (t2) is also subdivided by a deep groove and terminates immediately in front of the gastric shield (gs). Posterior to the gastric shield the posterior chamber is finely transversely ridged on both floor and roof and functions as a sorting area (sa). These narrow, ciliated ridges are in marked contrast to the broad, low ridges (cr), separated by narrow grooves, that cross the roof of the anterior two-thirds of the stomach. These ridges are cuticularized, presumably to protect the epithelium from the rotation of the crystalline style. This ridged area is incor- rectly referred to as the sorting area by Davis et. al (1982). Fig. 44b illustrates the major fea- AUSTRALIAN SPRING HYDROBIIDS 75 FIG. 44. Stomachs of Trochidrobia punicea (a) and F. accepta form A (b) opened from outer (right) sides. Arrows in b indicate directions of main ciliary currents; letters A-E correspond approximately to sections with same letters in Fig. 45. cr, chitin-lined ridges; dgo, digestive gland opening; gs, gastric shield; ing, intestinal groove; int, intestine; oso, oesophageal opening; sa, sorting area; ss, style sac; t1, major typhlosole; Ла, t1b, folds developed from major typhlosole; t2, minor typhlosole; t2a, fold developed from minor typhlosole. Scale: 0.25mm. tures of the stomach with the dorsal (outer) wall opened. The transverse sections of the stomach of F. zeidleri (Fig. 45) show the re- lationships of the typhlosoles to the rest of the stomach and the extent of the ciliated epithe- lium. The digestive gland opening (dgo) lies pos- terior to the oesophageal opening. The diges- tive gland overlies the posterior end of the inner wall of the stomach and occupies the remainder of the visceral coil. It is composed predominantly of digestive cells with smaller excretory cells, which contain occasional ex- cretory granules, in the creases of the tu- bules. The intestine passes around the style sac, loops towards the anterior chamber of the stomach alongside the style sac, and then runs more or less straight to the right side of the mantle cavity. The rectum (Fig. 4F,R) passes along the right side of the mantle cav- ity and opens a little behind the mantle edge. The proximal part of the intestine contains a large typhlosole but the remainder is simple. Renal organ and pericardium. The renal or- gan lies behind the posterior wall of the man- tle cavity on the right side and opens to it by way of a short, dorsoventrally orientated slit (Fig. 4F,RO). This slit is located in the middle of the posterior pallial wall and is rendered conspicuous by white lips that surround it. The opening is lined with a ciliated, columnar epithelium and is surrounded by muscle fibres that presumably act as a sphincter. The renal epithelium is thin and simple, composed for the most part of a single layer of irregular cells. A nephridial gland occupies most of the outer wall. The pericardium also lies immediately be- hind the posterior pallial wall, but on the left side. It contains the heart, which consists of a well-developed ventrical and auricle. No reno- pericardial opening was observed. Nervous system (Fig. 43b). The nerve ring is embedded in a mass of spongy connective tissue composed partly of cells containing black pigment granules. The arrangement of the ganglia is essentially similar to that de- scribed for Hydrobia truncata (Vanatta) by Hershler and Davis (1980). The cerebral gan- glia (cgl) are joined by a commissure about as long as the width of a single cerebral gan- glion. Each cerebral ganglion gives off seven nerves anteriorly, the base of one of them, the tentacular nerve, being swollen. There is a long right pleuro-supra-oesophageal connec- 76 PONDER, HERSHLER & JENKINS FIG. 45. Sections through stomach of Fonscochlea zeidleri form A. Approximate positions indicated in Fig. 44b. cr, chitin-lined ridges; cs, crystalline style; dg, digestive gland; dgo, digestive gland opening; gs, gastric shield; int, intestine; oes, oesophagus; ss, style sac; t1, major typhlosole; tia, t1b, folds developed from major typhlosole; t2, minor typhlosole. Scale: 0.25mm. tive (rp-spo) and the left pleural (Ip) and sub- oesophageal ganglia (sbo) are fused. The cerebro-pedal complex is also very similar to that described for H. truncata except that the cerebropedal connectives are rela- tively shorter than the pleuropedal connec- tives. Only the cerebral, pedal and buccal ganglia are pigmented. Male genital system (Fig. 46a). The testis occupies the upper surface of most of the vis- ceral coil behind the stomach. It is complexly lobed, with five lobes each containing approx- imately 15 to 20 lobules. The visceral section of the vas deferens forms a seminal vesicle that lies coiled beneath the anterior half to two-thirds of the testis. When straightened the seminal vesicle is about one and two-thirds times longer than the shell. A more or less straight part of the seminal vesicle emerges from beneath the testis and runs across the ventral side of the stomach. This duct narrows before entering the prostate gland immedi- ately behind the posterior pallial wall. This large gland extends partly (0.1 to 0.45 of its total length) into the right side of the mantle cavity. The prostate has thickly glandular ‚ walls except in its mid-ventral portion where the vas deferens opens and leaves. The pal- lial portion of the vas deferens opens imme- diately in front of the posterior pallial wall and runs as a Straight tube along the right side of the mantle cavity until it is close to the base of the penis. Here it undulates for a short dis- tance before entering the penis. The pallial vas deferens lies just beneath the surface of the epithelium, has a simple, ciliated epithe- lium and is not surrounded by muscle fibers. The penis (Fig. 46a), coiled twice anticlock- wise as seen from above, is attached to the midline behind the head. The distance of the anterior edge of the penial attachment behind the eyes is only slightly less than the distance between the tentacle bases and about two- thirds the length of the snout. The penial duct AUSTRALIAN SPRING HYDROBIIDS 77 FIG. 46. a. Dorsal view of penis of Fonscochlea accepta form A, Welcome Springs, preserved material. b. Ventral view of living penis of Fonscochlea zeidleri form A, Blanche Cup. e, eye; p, penis; vd, pallial vas deferens. Scale: 0.25mm. lies close to the outer edge of the penis and is similar to the pallial vas deferens in structure. К coils in the broad, proximal quarter of the penis and is straight in the remainder. The distal part of the penis is long and tapers to a point. Unlike the basal part it is not trans- versely ridged and has longitudinal stripes that correspond to strands of longitudinal muscle lying beneath the epithelium. There are no penial glands or cilia; the epithelium is covered with cuticle. Female genital system (Figs. 12d,g,h, F. accepta form А; 47, Е. zeidleri). The ovary is a simple sac filled with about 17 eggs in a mature individual. It is about one-half the length of the digestive gland and lies behind the posterior end of the stomach. The thin- walled oviduct is lined with pale-staining, un- ciliated cells and passes straight across the ventral wall of the stomach to a position just behind the posterior pallial wall. At this point there is a sudden change to a ciliated cuboi- dal epithelium that is thrown into longitudinal folds marking the commencement of the coiled section of the oviduct. The longitudinal folds in the first part of the coiled oviduct persist for only a short dis- tance, the lumen becoming oval. The initial section of the coiled oviduct probably repre- sents the renal section of the oviduct. It passes very close to the renal organ but no open reno-gonadial duct was observed in sections or in dissection. There are, however, strands of tissue connecting the most proxi- mal portion of the duct to the kidney wall and some modification of the kidney tissue was apparent in this region. The cells increase in size in the section following the renal part and they are more or less cuboidal with a few blue-staining (in Mallory’s Triple Stain) gland cells apparent. The coiled part of the oviduct (co), at this point, is surrounded by a few mus- cle fibres. It bends sharply upwards and then loops down to run forward along the albumen gland (ag). Near the posterior end of the al- bumen gland it loops upwards and two spher- ical sperm pouches open to it. In this region the coiled oviduct is surrounded by an outer coat of circular muscle. The epithelium is thrown into a few low, longitudinal folds and sperm are attached to the ciliated epithelial cells. The oviduct increases in diameter and 78 PONDER, HERSHLER & JENKINS mcp FIG. 47. Female genitalia of Fonscochlea zeidleri form A, from the left side. ag, albumen gland; bc, bursa copulatrix; bcd, duct of bursa copulatrix; cg, capsule gland; co, coiled part of oviduct; go, female genital opening; mcp, posterior limit of mantle cavity; sr, seminal receptacle; srd, duct of seminal receptacle; uo, upper oviduct; vc, ventral channel; vcp, posterior extension of ventral channel. Scale: 0.2mm. loops upwards to lie behind, and sometimes above, the proximal loop. It then opens ven- trally into the posterior end of the capsule gland (cg). This tubular extension (vpc) of the sperm groove in the ventral channel is lined with an epithelium similar to that of the sperm groove, the cuboidal cells bearing conspicu- ous cilia and occasional blue-staining gland cells. The two sperm pouches (bc, sr) lie near the posterior end of the albumen gland on the inner (left) side of the gland and their short ducts extend from their ventral walls to open separately into the oviduct. They are identical in histology and appearance and might both be homologous with the bursa copulatrix of other hydrobiids. They are lined with long, purple-staining cells with dense, finely- staining contents and basal nuclei. Unori- ented sperm fill the lumen in most specimens and additional sperm have their heads at- tached to the outer surface of the epithelial cells. Each sperm sac is surrounded by a coat of muscle and their ducts, which also contain sperm with their heads attached to the epithe- lial cells, are similar in structure to the oviduct in this region. The oviduct gland of F. zeidleri (Fig. 47) is typical of those in all the species of Fonscoch- lea. It consists of a blue-staining albumen AUSTRALIAN SPRING HYDROBIIDS 79 gland (ag), which lies behind the posterior pallial wall, and a red-purple staining capsule gland (cg), which lies in front of this wall. The two glands are, however, externally continu- ous. The lumen of the albumen gland is con- tinuous with that of the capsule gland and cil- iated cells line the lumina of both. The tubular oviduct opens to the thin-walled ventral chan- nel (vc) ofthe capsule gland, part of which, on the left, is separated from the main channel by a ciliated, nonglandular fold. This fold con- tinues throughout the ventral channel to the small, subterminal, ventral opening and sep- arates the sperm-conducting channel, on the left, from the egg-conducting channel. The very thin ventral wall of the egg-conducting channel is lined with small, cuboidal, uncili- ated cells. In the vicinity of the oviduct open- ing the gland cells in the ventral part of the capsule gland change from red- to pale-blue- staining. The anatomy of Fonscochlea accepta is typical of all the species of Fonscochlea. The most important character that separates this genus from all other genera in the family is the equal-sized sperm sacs that seem to have been developed from a subdivided bursa cop- ulatrix. Their arrangement differs in detail in the two subgenera of Fonscochlea, as de- scribed in the taxonomic section (compare Figs. 12c-h and 27a-d with Figs. 12a,b and 47). In most other respects the anatomy of species of Fonscochlea is similar to that of other species of the family Hydrobiidae. Anatomical description of Trochidrobia pu- nicea: Head-foot (Fig. 24h). The snout is about two-thirds the length of the tentacles when at rest but when extended is about the same length. It has a bilobed tip that is slightly narrower than the rest of the snout, and is pigmented dark grey to black, the tip being unpigmented in many specimens. The ceph- alic tentacles are parallel-sided, held at about 45°, sway slowly up and down through a small arc (species of Fonscochlea move their ten- tacles through a greater arc and more rapidly) and are pigmented light to dark grey, often with a narrow, white median line. A few scat- tered, dense-white spots lie on the inside proximal end of the tentacles anterior to the eyes and a conspicuous group of these spots lies on the inner side of the eyes and, some- times, behind them. The large, black eyes are in bulges at the outer bases of the tentacles and are, in some specimens, surrounded by black pigment, but in others the black pigment lies mainly behind the eyes. The dorsal head and ‘neck’ are grey to black and a ciliated rejection tract runs down both the sides of the head onto the foot. The foot is almost as long as the shell is wide and is about one-third as wide as long. Only a very short portion extends beyond the operculum and, normally, the foot is invisible when the crawling animal is viewed from above. There are lateral constrictions behind the anterior edge, and the posterior end is evenly rounded. A well-developed pedal gland opens to the anterior edge of the foot and the sole is supplied with subepithelial glands. The entire sole and the lateral edges of the foot are covered with posteriorly beat- ing cilia. The anterior edge has cilia beating towards the outer corners. The foot is pig- mented grey to black on the anterior and pos- terior dorsal surfaces and is paler to unpig- mented dorsolaterally. The sole is dark grey to whitish, the colour being imparted by pig- ment-bearing cells in the connective tissue in the cephalic haemocoel. The mantle collar is richly supplied with dense-white cells across the outer lip but these are fewer across the inner lip where there is more black pigment. This black pig- ment is predominantly in subepithelial cells, but, with the exception of the sole, the remain- der of the pigment on the head-foot is con- tained in epithelial cells. Mantle cavity (Fig. 48). The mantle cavity is short and broad, being slightly wider than it is long. The well-developed ctenidium (ct) is placed diagonally across the cavity and the apices of the filaments lie at their right edge. A short, oval osphradium (os) lies alongside the posterior end of the ctenidium. It is similar in structure to that of species of Fonscochlea. There is no hypobranchial gland. The rectum (r) and genital duct (cg) run down the right side of the cavity and the anus (a) lies close to the mantle edge. The ctenidium lies closer to the mantle edge, ending just inside the mantle skirt (me). Alimentary system. The mouth opens to a short, cuticle-lined oral tube with a pair of small jaws laterodorsally. The well-developed buccal mass occupies most of the snout and a coiled radular sac emerges posteriorly from it. The anterior part of the oesophagus (mid- oesophagus) has long dorsal folds, which are curved dorsally, occupying most of the lumen. The lateral and ventral walls are lined with a ciliated, cuboidal epithelium with purple- 80 PONDER, HERSHLER & JENKINS OS ct FIG. 48. Dissection of pallial cavity of Trochidrobia punicea. Double-headed arrow indicates separation of kidney from dorsal pallial wall. a, anus; cg, capsule gland; ct, ctenidium; go, female genital opening; mcp, posterior limit of mantle cavity; me, mantle edge; os, osphradium; r, rectum; rg, renal organ; ro, renal opening. Scale: 0.2тт. staining, granular contents. This section of the oesophagus terminates at the end of the cephalic cavity, the posterior oesophagus be- ing narrower and without the dorsal folds. The simple, tubular salivary glands lie dorsal to the nerve ring. The stomach (Fig. 44a) is similar in general appearance externally to that of species of Fonscochlea. The style sac communicates with the intestine along all of its length. The well-developed typhlosoles (t1, t2) within the stomach are unpigmented and readily dis- cernible against the stomach wall. The major typhlosole (t1) extends to the posterior end of the stomach where it swings around the di- gestive gland opening after fusing with the mi- nor typhlosole (t2). Short left (t2a) and right branches of the fused minor + major typhlo- sole are given off that extend onto the roof of the posterior end of the stomach. The gastric shield lies close to the oesophageal (050) and digestive gland (dgo) openings. These open- ings lie at either end of a groove that divides the major typhlosole (t1) into two arms. This typhlosole splits into two folds at the anterior end of the oesophageal opening, the right fold running to the anterior edge of the gastric shield and the left fusing with the minor ‘typhlosole near the digestive gland opening at the posterior end of the stomach. The typhlosoles, style sac, and the poste- rior end of the stomach are ciliated, the re- mainder of the gastric epithelium being cutic- ularized. The pigmented roof of the anterior chamber is very indistinctly marked with widely separated narrow grooves (cr). The digestive gland and intestine are very similar to those of Fonscochlea. The digestive gland covers the inner, ventral, side of the stomach to half-way across the anterior chamber. Renal organ and pericardium. The renal or- gan (kidney) lies behind the posterior wall of the pallial cavity. The lumen is severely re- duced, particularly in females, by the invagi- nation of the genitalia. The renal opening (Fig. AUSTRALIAN SPRING HYDROBIIDS 81 FIG. 49. Penes of Trochidrobia punicea, Blanche Cup (a.) and Trochidrobia smithi, Outside Springs (b.). a, eye; p, penis; vd, pallial vas deferens. Scale: 0.1тт 48, ro) lies in the middle of the posterior wall of the pallial cavity. It is a short, vertical slit surrounded by thickened, ciliated, white lips (sphincter muscle). The renal epithelium is simple and very thin except on the outer wall where it forms a thick nephridial gland. The pericardium lies behind the left side of the posterior pallial wall and the base of the ctenidium. Its posterior face abuts against the anterior end of the style sac. The ventricle and auricle are both well developed. Nervous system. The cerebral ganglia are joined by а commissure that is slightly shorter than the width of the cerebral ganglia. The pleural ganglia are fused to the cerebral gan- glia but a waist-like constriction separates them. The supra-oesophageal ganglion is a little longer than the width of the cerebral gan- glia, and the right pleuro-oesophageal con- nective is about the same length as the cere- bral ganglia. The suboesophageal ganglion abuts the left pleural ganglion. All of these ganglia, and the buccal and pedal ganglia, are pigmented except for the supra-oesoph- ageal ganglion. Male genital system. The testis consists of several lobes, each consisting of numerous lobules, about 45 in the anterior lobe. The vas deferens lies coiled beneath the anterior two lobes of the testis. It runs forward as an al- most straight tube, narrows across the inner (ventral) side of the stomach and terminates just behind the posterior pallial wall where it opens to the middle part of the prostate gland. The pallial section of the vas deferens leaves the prostate gland immediately in front of the posterior pallial wall and runs along the groove at the junction of the mantle cavity floor and the mantle roof. It is straight until it nears the base of the penis where it undulates across the right side of the “neck” before en- tering the penis. The large prostate gland is reniform, narrowly oval in section, thickly glandular, with a thin ventral wall only in the vicinity of the point of entry and departure of the vas deferens. It lies partly in the pallial roof and partly behind the posterior pallial wall. Its extent of penetration of the pallial roof varies from one-third to one-half of its total length. The penis (Fig. 49a) lies just to the right side of the midline of the head at a distance behind the eyes about equal to the length of the snout. It is coiled twice anticlockwise in preserved material. The base of the penis is swollen and unpigmented, at least in the proximal part, and has clearly defined creases running across its surface. The remainder of the organ is pale to dark grey along much of its length, the proximal part 82 PONDER, HERSHLER & JENKINS often being unpigmented. It is smooth and tapers to a point. The inner side of the penis, i.e. the edge on the inner side of the coil, is flattened to almost channelled in some individuals and rounded in others. The penial duct is, like the pallial vas deferens, ciliated, thin-walled and very narrow. The penis is surrounded by an unciliated, non-cuticular- ized cuboidal epithelium. It contains some pale-blue staining subepithelial gland cells amongst the muscle and connective tissue. Distinct penial glands are absent. Female genital system (Fig. 36b). The ovary is short relative to the digestive gland. The upper oviduct (uo) is a straight, thin- walled tube that passes across the ventral surface of the stomach before reaching a point close to the pericardium and the renal organ. Here its walls thicken and the ciliated epithelium is raised into longitudinal ridges. There is no gonopericardial or renogonadial duct although a tissue connection (st) with the pericardium can be seen in dissection. The renal section of the oviduct is extremely short and is invaginated within the renai wall. The coiled oviduct (co), the first, very short part of which is the renal oviduct, is coiled behind the posterior pallial wall (mcp) on the left side of the albumen gland. It is consider- ably swollen in this species, a character not seen in other species of the genus. It invagi- nates into the renal organ, considerably re- ducing the volume of the renal lumen. The outer wall of the coiled oviduct is surrounded by an outer layer of circular muscle fibres and a thicker inner layer of longitudinal fibres and is lined with a ciliated cuboidal epithelium. Spermatozoa are stored in the lumen of the coiled oviduct, and are aligned more or less longitudinally, apparently by ciliary action. The large bursa copulatrix lies behind the coiled oviduct and its right (outer) wall is em- bedded in the albumen gland. There is a short, free bursal duct (about one-fifth the length of the bursa), the remainder of the duct merging with the coiled oviduct and running back along it. The bursal duct eventually opens to the coiled oviduct but the exact point of opening was not established because the two tubes are enveloped in a common sheath of connective tissue. The bursa copulatrix (bc) is lined with an unciliated, purple-staining columnar epithelium with granular cytoplasm and basal nuclei. In all specimens sectioned, the bursa did not contain sperm. The oviduct anterior to the bursal duct con- tinues as a short, broad tube, for a distance TABLE 10. Shell heights for the snail taxa used in the physiology experiments. Range of shell heights (means, sexes pooled) among Species populations (mm) F. accepta form A 3.16-3.57 Е. accepta form В 2.83-3.41 F. aquatica 3.93-4.50 F. variabilis 1.41-2.52 F. conica 1.70-2.18 F. zeidleri 2.97-4.37 T. punicea 1.60-1.91 (shell width) approximately equal to the length of the bursa, to the posterior wall of the pallial cavity where it opens to the capsule gland (cg) as the ventral channel. This oviducal tube is lined with ciliated cells, amongst which are scattered larger, blue-staining gland cells. The oviduct gland is clearly divided into a blue-staining albumen gland (ag) lying behind the pallial cavity and, continuous with it, a red- staining capsule gland (cg) in front of the pos- terior pallial wall. The albumen gland opens to the capsule gland which, immediately in front of the junction of the two glands, receives the oviduct. This tube opens to the ventral chan- nel (vc) of the capsule gland into a ciliated gutter, similar to that in species of Fonscoch- lea, which runs to a slit-like opening (go) sit- uated about one-third of the length of the cap- sule gland from its anterior end. The capsule gland is, however, relatively shorter and broader than that of species of Fonscochlea. In the vicinity of the genital opening the glan- . dular epithelium in the ventral part of the cap- sule gland forms a pale-blue zone. The main feature of interest in the anatomy of this genus is the lack of a seminal recep- tacle and the development of accessory sperm storage in the coiled oviduct. In Troch- idrobia smithi sperm storage takes place in the ventral channel. In other respects the anatomy is typical of the family Hydrobiidae. Physiology The taxa examined fall into four main groups, distinguished by differences in shell size (Table 10) and habits: 1) F. zeidleri form A, the amphibious species; 2) large aquatic species (F. aquatica form A and cf. form A, and F. accepta); 3) small, aquatic Fonscoch- AUSTRALIAN SPRING HYDROBIIDS 83 TABLE 11. Survivorship of snails in dry dishes. Ten snails were used in each experiment. Т1 = Trochidrobia punicea, F1=Fonscochlea accepta, F2 = Fonscochlea aquatica, F3 = Fonscochlea variabilis, F4 = Fonscochlea conica, F5 = Fonscochlea zeidleri. BC=Blanche Cup, CS = Coward Springs Railway Bore, FS=Finniss Springs. Species (population) Number T1 T1 F3 F3 F5 F5 F5 of hours (run 1) (run 2) F4 (BC) (CS) F1 F1b F2 (FS) (BC) (CS) 1 8 5 2 Y 8 10 10 9 10 10 10 2 5 2 0 4 5 7 10 9 10 8 10 4 2 0 0 1 4 6 10 9 9 9 10 6 0 0 0 0 3 1 8 6 10 9 10 12 0! 0 0 0 0 0 5 9 10 Te 24 0' 0 0 0 0 2 3 93 9 9 48 02 0 0 0 0 0 0 83 9 6 Date & 27-8 2-9 3-9 21-8 1-9 3-9 29-8 31-8 28-8 30-8 1-9 time commenced 11:30AM 8:15AM 10:15AM 9:00AM 8:00AM 9:25AM 8:00AM 9:30AM 8:00AM 8:40AM 7:45AM !commenced at 6:30PM 2commenced at 3:34PM ®commenced at 8:40AM “dish checked after 10 minutes, but not after one hour. lea species (F. conica, F. variabilis form A); sons, P < 0.05). At 12 hours, only the and 4) Trochidrobia punicea, small and Blanche Cup F. zeidleri population had a sig- aquatic. nificantly higher survival than that of F. ac- Desiccation. During the 48 hours that these сера form В (Р = 0.025). There was no sig- experiments were run, there was no mortality nificant difference in survival amongst the in any of the wet, control dishes of any of the three F. zeidleri populations at any time. species. The results for the moist dishes were Survival of two of the three large aquatic the same, except that at 48 hours the two Fonscochlea taxa, F. accepta form A, F. ac- populations of F. variabilis tested had 90% cepta form B and F. aquatica, was good (Coward Springs Railway Bore) and 100% through 12 hours (50%) and higher than that (Blanche Cup) mortality (results significantly of the small aquatic Fonscochlea species (F. different from those for the other species, conica and F. variabilis): for F. accepta form Fisher's Exact Test, Р < 0.005). The results B, this difference was significant at two, four, are summarized in Table 11. six, 12, and 24 hours (for all pairwise compar- Only F. zeidleri survived well (60-90% in isons, P < 0.05), for F. aquatica, the difference the three populations tested) after 48 hours in was significant at four and 12 hours (P < the dry dishes (Figs. 50-52). Fonscochlea 0.05). Both F. accepta form B and F. aquatica aquatica cf. form A (Kewson Hill) had 10% had higher survival than the other large survival after 48 hours (significantly less than aquatic species, F. accepta form A, after six that of any F. zeidleri population, P < 0.05) and 12 hours (all pairwise comparisons, P < and 50% mortality after only one hour. The 0.05), but not at 24 hours. At no point during other species had higher mortalities. F. con- the experiments did the former two taxa differ ica had 80% mortality after one hour and significantly from each other in survival. 100% mortality after two hours, T. punicea There were no significant differences in 50-80% mortality after two hours and 100% survival seen in any of the pairwise compari- mortality after 6 hours, F. variabilis 50% mor- sons for any time between the two popula- tality after two hours and 100% mortality after tions of F. variabilis and the two runs of T. 12 hours and F. aquatica and F. accepta punicea (Finniss Springs), except for that be- 100% mortality after 48 hours (see below for tween T. punicea and F. variabilis from Cow- details). After 24 and 48 hours, all three F. ard Springs Railway Bore after four hours zeidleri populations had significantly higher (P=0.05). Both of these species showed a survival than that of the next best “survivor”, fairly rapid onset of mortality. Yet after two F. accepta form B (for all pairwise compari- hours both of the above species had a signif- 84 PONDER, HERSHLER & JENKINS TEMPERATURE (°C.) 0700 0700 0700 2-9 SEQ) 4-9 TIME OF DAY RELATIVE HUMIDITY (PER CENT) 0815 0700 0830 1400 5-9 6-9 7-9 FIG. 50. Running record of air temperature and humidity in tent for duration of experiments. Readings taken hourly, generally from 0600 to 2200; dashed lines indicate intervals at night during which readings were not taken. icantly higher survival than F. conica (all com- parisons, P < 0.05), which already had 100% mortality at that time. Fonscochlea aquatica from Kewson Hill showed the peculiar pattern of fairly rapid on- set of mortality (50% after one and two hours), followed by survival of 10% of the snails after 12, 24, and 48 hours. Salinity: Nearly 100% of the snails, for all species, remained active in the control jars for the duration of the experiment. At 24 hours, 98% of the snails (for all species pooled) were active. The results for salinities of 6, 9, and 12%. are given in Table 12. In 6%o salt water, nearly 100% of the spec- imens of F. zeidleri, F. aquatica, and F. ac- cepta form B remained active throughout the experiment: after 24 hours, for these species pooled, 91% of the snails were active and there were no significant differences in activ- ity among these species. However, activity did decline markedly in F. variabilis after two hours and in T. punicea after 24 hours. At 12 and 24 hours, the number of active snails of F. variabilis (either population) was signifi- cantly less (Fisher's Exact Test, Р < 0.05) than that of the species listed above for all pairwise comparisons but one (F. accepta form B-F. variabilis, Coward Springs Railway Bore). For T. punicea, at 12 hours, the num- ber of active snails was significantly less than that of only F. адиайса from Kewson Hill and F. zeidleri and Coward Springs Railway Bore (P < 0.005). At 24 hours, the number was significantly lower than that seen in any of the above group of species (P < 0.005). A signif- ‚ icantly larger number of T. punicea were ac- tive than F. variabilis (both populations) at two, three, six, and 12 hours (for all compar- isons, Р < 0.025). In 12%. salt water, activity of F. zeidleri and the large aquatic species remained топ. After 24 hours, for all species pooled, 80% of the snails were active and there were no signifi- cant differences among species. There were, however, several significant differences seen in the early hours of the experiment when ac- climitization was apparently occurring. There was no activity for both F. variabilis and T. punicea for the duration of this experiment. At six, 12, and 24 hours, the number of active snails for these species (0) was significantly lower than that of the above group of species (for all comparisons, P < 0.025). AUSTRALIAN SPRING HYDROBIIDS 85 NO. OF SURVIVING SNAILS YAA 24 NO. OF HOURS FIG. 51. Survivorship of large-sized species of Fons- cochlea in dry dishes. Fonscochlea accepta form A, solid circles; F. accepta form B, open triangles; Fonscochlea aquatica form A, open circles; F. zeid- leri form A represented by line with error bars, rep- resenting range of results among populations of that species. At 24%. salt water, with two exceptions (in which case a few snails were active at only one point in the experiment), activity was nil for all species throughout the experiment. Deoxygenated water. The results are given in Table 13. In the control tubes, initially sup- plied with oxygenated water, activity generally decreased markedly by six hours, and only 26% of the snails (for all species pooled) were active by 20 hours. In four experiments, the snails in the control tubes were tested for sur- vival, in the same manner as were those snails in the tubes with deoxygenated water, after 20 hours; 90% of these snails (all spe- cies pooled, N=80) were alive, although some were sluggish. The decrease in activity and occasional mortality could have been due to deoxygenation of the water in the small 15 cc test tubes during the course of the ex- periment. In the test tubes initially supplied with deox- ygenated water, again activity decreased markedly during the course of the experi- ments, with only 26% of the snails (all species pooled) active at six hours, and 13% at 20 hours. Despite this decrease in activity, sur- NO. OF SURVIVING SNAILS 1 2046 A NO. OF HOURS FIG. 52. Survivorship of small-sized species of Fons- cochlea and Trochidrobia punicea in dry dishes. Trochidrobia punicea, solid squares (two runs pooled); Fonscochlea conica, open circles; Fons- cochlea variabilis form A, solid circles (runs for dif- ferent populations of this species pooled). Error bars represent ranges of results. vival for all species, except T. punicea, was near 100% at all times. In general, the snails became active during the first ten minutes af- ter being placed in oxygenated water. Sur- vival of T. punicea was significantly less than that of all other species tested at four hours (all pairwise comparisons, Chi-Square Test of Independence, one-tailed, Р < 0.005), six hours (P < 0.05) and 20 hours (P < 0.005). There were no significant differences in sur- vival between any two of the other species. Temperature. The results (Table 14) indi- cate that, in general, almost all individuals of all species tested remained active at 10— 32°C., and a large percentage of individuals were active at 5° (76% for all species pooled), 35° (77%) and 37° (41%). At the lower end of the temperature range, the snails generally became more and more sluggish, whereas at the upper range of the temperature range, ac- tivity greatly increased and, at a slightly higher temperature, was followed by slug- gishness and cessation of activity. Considerable variation was seen in the in- stances in which several populations of a spe- 86 PONDER, HERSHLER & JENKINS TABLE 12. Activity of snails over time in water of salinities of 6%, 9%, and 12%. Ten snails were used in each experiment unless otherwise indicated. The approximate natural salinity of the water used in the experiments is given for each sample (calculated from the conductivity). FS = Finniss Springs, CSRB = Coward Springs Railway Bore, BC = Blanche Cup. 6%o Number of hours Number of hours 9%o 12% Number of hours Species Date, time (population) Salinity 1 2 3 6 12 24 1 2 3 6 12 24 1 2 3 6 12 24 commenced F. zeidleri (FS) 1.8 9 6 10 9 6 10 4 5 8 5 9 9 2 4 9 6 9 9 298 10:55AM Е. zeidleri (CSRB) 2 10 10 10 10 10 9 10 10 10 10 10 10 2 3 7 8 9 8 1.9 9:30AM F. zeidleri (BC) 36 10 10 10 10 9 10 10 10 10 7 8 9109 8 7 6 9 308 10:20AM Е. адиайса 36 1010 810 9 10 8 8-7 т 8 9 9 6 6 5 З 7 308 12525М F.accepaformB 18 1010 9 7 7 99997 4 10 8 2 5 5 5 9 29:8 9:10AM F. variabilis 3.6 69 9 9 6 yo 41 2 of 0 0 0 0 0 0 0 31:8) 10:50AM (BC)' F. variabilis 2 10° 9 9 7 10 710 2 0 O 31 2 00 0 0 О O 29 9:330АМ (CRSB) T. punicea 1:8 10 10 9 9 10 10 810 8 9 6 2 0 0 0 0 O O 28:8) 8:20AM 111 specimens used TABLE 13. Survivorship and activity of snails in deoxygenated water. Activity of snails in control tubes (initially supplied with oxygenated water) also shown. Twenty snails were used in each experiment unless otherwise indicated. FS = Finniss Springs, BC = Blanche Cup, and CS = Coward Springs Railway Bore. % of snails active in tube % of snails surviving % of snails active in control tube Number of hours Species Date, Time (population) 1 2 4 6 О 2416 201 2 4 6 20 Comm. F. zeidleri (CS) 100 100 100 100 100 45 40 45 75 О0 100 100 80 95 5 1.9. 11:05AM Е. zeidleri (BC) 100 100 100° 100'6 100 87 15 30 0 0 100 90 90 85 80 30.8. 12:00PM Е. zeidleri (FS) 100 100 100 90 100 15 10 5 0 0 100 100 80 25 10 28.8. 10:30AM F. accepta 100 100 100° 100 100 95 95 30 60 10 100 100 80 75 20 29.8. 10:55AM form B (FS) F. variabilis 90 100 100 100 100 30 30 40 10 0 100 100 100 45 0 31.8. 11:25AM (10 snails/tube) F. conica 100 100 100 90 100 60 90 90 30 0 100 100 100 90 50 3.9. 12:30PM T. punicea 95 100 50 60 35 65 60 10 10 0 90 60 30 25 5 29 7 3:00RM 1616 specimens used ‘#18 specimens used '919 specimens used cies were tested. For F. zeidleri, at 2° the Blanche Cup population had a significantly larger number of individuals active than did the other two populations (P < 0.0005 Chi- Square); at 35° the Coward Springs Railway Bore population had significantly larger num- ber of active snails than did the other two (P < 0.01, Chi-Square); at 37°, the Coward Springs Railway Bore population had significantly higher activity than did the Blanche Cup pop- ulation (P = 0.025, Fisher’s Exact Test), which in turn had higher activity than did that of Fin- niss Springs (P < 0.01, Chi-Square); at 40 and 42° the Coward Springs Railway Bore population had a significantly higher activity than had the other two populations (Р < 0.0005, Chi-Square). While F. accepta form B had significantly higher activity than did F. ac- AUSTRALIAN SPRING HYDROBIIDS 87 TABLE 14. Numbers of snails active at various water temperatures. Twenty snails were used for each experiment unless otherwise indicated. FS = Finniss Springs, BC = Blanche Cup, CS = Coward Springs Railway Bore. ASS AAN Temperature (*C) Species Date (population) OM 257507 E77 2757107157 207°7257:307327 357 37 40 42" 45 47 50 Comm: F. zeidleri (FS) — 0 2 3 5 72.207207 2055205208 207200 77762502 — — 2.9 F. zeidleri (BC) OB 23205 202207720205207 20 85 8) 0) 0e F. zeidleri (CS) == = — 0 91520520! 220) 20) 20)" 20) 19} 20201 бе = 1.9 F. aquatica 0 — — 2 4 4 17 19 20 20 20 20 18 16 18 0 — — — — 308 Е. acceptaformB — — — 0 9 16 20 20 20 20 20 20 20 15 11 2 4 0 — — 1.9 Е. accepta form A — — 0 2 3 5 19 20 20 20 20 20 20 20 20 10 4 0 — — 3.9 Е. variabilis (BC) — — — — 0% 1 4 20 20 20 20 19 20 20 19 3 0 — — — 308 Е. variabilis (CS) — — — — — 0 2 19 19 20 20 20 20 20 20 16 5 0 — — 1.9 F. conica — — — — — 0 10 19 29 29 29 29 29 19 19 19180 — — 3.9 T. punicea == — 0 1 8 20 20 20 20 20 20 20 18 5 0 —= — — — 1.9 114.5" 2.44° 99,5" cepta form A (and F. aquatica) at 2° (P < populations, except F. zeidleri from Finniss 0.005), F. accepta form A had significantly Springs, nearly all of the snails were active higher activity at 37” (P=0.006, Fisher's Ex- throughout the experiment (at 72 hours, for all act Test) and 40° (P < 0.01, Chi-Square species pooled, 95% of the snails were Test). active). Fonscochlea zeidleri from Finniss The F. variabilis population from Coward Springs showed reduced activity at 24 hours Springs Railway Bore had a significantly (40% of snails active), 48 hours (50%), and higher activity than did that from Blanche Cup 72 hours (30%). The number of active snails at 40° (P < 0.0005, Chi-Square) and 42° for this population was significantly less than (P=0.025, Fisher's Exact Test), probably re- that of all other populations at all three of flecting the higher water temperature at the these time periods (for all pairwise compari- bore. sons, P <= 0:005; Р - 0.05, P - 0.005. те- There were no consistent significant differ- spectively, Chi-Square). ences in activity between F. zeidleri and the Submergence preference. The results are large aquatic Fonscochlea species at any tem- given in Table 15. For two of the three F. zei- perature. Fonscochlea aquatica from Kewson еп populations tested, those from Finniss Hill, though, did show a reduced level of ac- Springs and Blanche Cup, over 50% of the tivity in high temperatures relative to the other individuals moved to the top of the plate; species: at 37° its activity was significantly less many moved far beyond the water meniscus than that of all these other species (plus the and became dry. Although these two popula- small Fonscochlea species, Р < 0.01, Fisher's tions did not differ significantly in proportion of Exact Test). Fonscochlea conica had a signif- individuals on the top of the dish, the Blanche icantly higher activity than did F. variabilis at Cup population did have a significantly larger 42° (P < 0.0005, Chi-Square). Trochidrobia proportion of individuals on the bottom of the purnicea had significantly less activity at 37° plate (32% v 8%, P < 0.005, Chi-Square). than had all other taxa except F. zeidleri from Both of these populations had a significantly Finniss Springs, F. адиайса from Kewson Hill, larger number of individuals on the rim of the and F. accepta form B (P < 0.005, Chi- dish than did the aquatic population of F. zeid- Square). [еп from Coward Springs Railway Bore, which Submergence tolerance. All populations had only 16% (P < 0.025, Chi-Square). were tested for submergence tolerance ex- For F. aquatica from Kewson Hill and F. cept those from Coward Springs Railway accepta form A, again more than half of the Bore and Welcome Springs. For all of these individuals migrated to the top (52% and 76%, 88 PONDER, HERSHLER & JENKINS TABLE 15. Results of the submergence preference experiments for snails. “Bottom”, “sides” and “top” refer to positions in the plate. Fifty snails were used in each experiment unless otherwise indicated. FS = Finniss Springs, BC = Blanche Cup, and CS = Coward Springs Railway Bore. NUMBER OF SNAILS Species (population) Bottom Sides Top F. aquatica 2 19 9 Е. accepta form В (N = 103) 9 51 43 Е. accepta form А 3 9 38 F. variabilis (BC) 27 17 6 F. variabilis (CS) 41 9 0 F. zeidleri (FS) 4 19 29 F. zeidleri (BC) 16 9 25 F. zeidleri (CS) 25 1174 8 F. conica 18 32 0 T. punicea (N =52) 30 22 0 respectively), but it was noted that for these species, and for those discussed below, the individuals on the top of the dish tended to cluster at or just above the water level, in some cases actually dragging the meniscus upward, and did not dry out. The three large Fonscoch- lea aquatic taxa tested differed significantly from one another in proportion of individuals on the top of the dish. Fonscochlea accepta form A had a higher proportion (76%) than did Е. accepta form В (42%, Р < 0.005, Chi- Square), which in turn had a higher proportion than did F. aquatica (18%, P < 0.05, Chi- Square). Рог F. адиайса, a significantly larger proportion of the individuals stayed at the bot- tom ofthe dish (44%) than for both ofthe forms of F. accepta (6-9%, P < 0.05, Chi-Square). Apart from 12% of the F. variabilis from Blanche Cup, none of the individuals of the small aquatic Fonscochlea species and T. pu- nicea migrated to the top of the dishes. For all pairwise comparisons, except F. variabilis (Blanche Cup)-F. aquatica and F. variabilis (Blanche Cup)-F. zeidleri (Coward Springs Railway Bore), the proportion of individuals of these species on the top of the dish was sig- nificantly less than that of all other taxa tested (P < 0.005, Chi-Square). Fonscochlea vari- abilis from Coward Springs Railway Bore, in particular, tended to stay on the bottom of the dish, rather than the sides or top (82%, sig- nificantly higher proportion than that of all other species and populations tested, P < 0.05, Chi-Square). Response to light. The results of these ex- periments are given in Table 16. Significant differences between runs, in the nine cases in which the experiments were repeated, were seen only for F. zeidleri (Finniss Springs and Coward Springs Railway Bore populations) and F. accepta (both forms). Of the other species tested, F. адиайса, F. variabilis, and F. conica all tended to cluster in the dark zones (at least 78% of the individu- als). Fonscochlea aquatica, in particular, showed this tendency, with an average, for the two runs, of 93% of the individuals clus- tered in the extreme dark zone. Fonscochlea accepta tended to be distributed more evenly between the light and dark zones and had a significantly lower proportion of individuals in the dark zones than did all of the above group of species (all pairwise comparisons, P < 0.01, Chi-Square). Trochidrobia punicea was the only species that showed a strong attrac- tion to light, with an average of 85% (two runs) of the individuals in the light zones, and had a significantly larger proportion of individ- uals in the light zones than did all other pop- ulations and species tested (all pairwise com- parisons, P < 0.05, Chi-Square). DISCUSSION Evolution and relationships of fauna The attempt to explain the origin and distri- bution of the hydrobiid species in the mound springs raises three questions: that of the ori- gin of the fauna, that о the mechanisms avail- able for that fauna to achieve its present dis- tribution, and that of the factors maintaining the present patterns. These questions are all discussed below in some detail. Geological history: The geological history of the mound springs is poorly understood. AUSTRALIAN SPRING HYDROBIIDS 89 TABLE 16. Results of the light response experiments for snails. The significance level for difference in results between runs (when two runs were done for a taxon) is given (Chi-Square Test, unless otherwise indicated). One hundred snails were used in each experiment. FS = Finniss Springs, CS = Coward Springs Railway Bore, BC = Blanche Cup. NUMBER OF SNAILS IN GIVEN ZONES Species Light- Dark- Light & Dark & Date, Time (population) Light Middle Middle Dark Light-Middle Dark-Middle S.L; Commenced F. accepta form A 41 6 A 42 47 53 28.8 50 14 1174 18 64 35 P <0.02 28.8 6:20PM Е. accepta form В 23 16 14 47 39 61 3.9 8:45AM 42 11 8 35 53 43 P <0.05 3.9 5:35PM F. aquatica 1 0 0 99 1 99 30.8 2 4 6 88 6 94 NS (Fisher's Exact Test) 28.8 4:15PM F. variabilis (BC) 11 0 3 86 a 89 — 31.8 Е. variabilis (CS) 2 2 2 94 4 96 2.9 2:50PM 1 6 26 67 Y 93 NS 1.9 F. conica 14 7 24 55 21 79 3.9 2:50PM 10 9 14 64 19 81 NS 3.9 F. zeidleri (FS) 58 12 8 22 70 30 2.9 10:25AM 7 3 15 75 10 90 P <0.001 28.8 10:55AM F. zeidleri (CS) 4 27 28 41 31 69 1.9 8:45AM 27 30 30 13 57 43 P <0.001 2.9 1:00PM F. zeidleri (BC) 16 25 32 27 41 59 — 30.8 Т. ритсеа 67 14 9 10 81 19 NS 2.9 11.25AM 74 15 6 5 89 dl 28.8 12.30PM Three large hills in the middle of the Lake Eyre group, Hamilton Hill and North and South Beresford Hills, are extinct mound springs. They were formed on a weathered Pleistocene land surface which lay 10-50 m above the present land surface (Wopfner & Twidale, 1967). Jessup and Norris (1971) have suggested that these fossil mounds are approximately equivalent in age to the Eta- dunna Formation (Miocene) but Wopfner and Twidale (1967) suggest that they commenced activity when gypsite sediments were being deposited over much of the Lake Eyre Basin between 80,000 and 40,000 years ago. Wopfner and Twidale postulate that spring activity began after uplift of the eastern rim of the Great Artesian Basin, when the wetter Pleistocene increased the amount of water held in the aquifers. They suggest that the (Pleistocene) freshwater limestones and trav- ertines were formed in “shallow pools sur- rounding these springs.” They also record reed casts and “Coxiella” from the lime- stones. It is likely that at least North Beresford Hill was raised at least several metres above the land surface that existed at that time. The fossil snails found in the limestones are closely similar to those living in the mound springs nearby, both Fonscochlea and Troch- idrobia being present (i.e. apart from one very small site on North Beresford Hill, they are not the salt lake-inhabiting Coxiella). Many Re- cent springs have similar snail and plant “fossils” in the limestones composing their mounds. We favour a Pleistocene age for these springs because of the lack of erosion on them. Habermehl (1982) has briefly discussed the theories that might account for the greater height and considerable size of the extinct mounds represented by Hamilton and Beres- ford Hills. He argues that the “great and ancient” mounds are related not to a much more abundant water discharge but to pro- longed, stable hydraulic conditions and that later unstable conditions led to lower, rela- tively small mounds. A drier, windier period in the Quaternary followed and the land surface was lowered partly by deflation and partly by erosion fol- 90 PONDER, HERSHLER & JENKINS lowing tectonic movements (Wopfner & Twidale, 1967). The formation of new springs at lower levels ensued in a stepwise manner (Habermehl, 1980, 1982) following the pro- gressive lowering of the pressure heads in the spring areas. Springs will tend to form at lower levels further reducing the pressure head in higher springs. Reduced flow will cause the outlets to clog and hasten the ex- tinction of the spring and clogging is acceler- ated by vegetation trapping windblown sedi- ments (Habermehl, 1980, 1982). As erosion lowers the ground surface the north-dipping aquifer is moved, relative to the ground surface, farther north. Thus if any Ter- tiary springs existed they might have been lo- cated to the south of the present springs. To date no evidence of such springs exists, with the possible exception of some fossil hydro- biid snails (Ludbrook, 1980) found in lime- stones, of presumed Miocene age, that cap plateaus near the Billa Kalina homestead ap- proximately 50 kilometres south of the near- est active mound springs. Ambrose and Flint (1981) have interpreted these limestones as part of a Miocene lake more than 100km wide. It is possible, however, that artesian springs could have been associated with this lake just as they are today in several dry salt lakes in the Lake Eyre basin. Some evidence for this view is the general similarity of the Billa Kalina snails to the large species of Fons- cochlea and their apparent concentration in large numbers only in a small area, a few tens of metres in extent, about 4km north of the Billa Kalina homestead, and their rarity or ab- sence elsewhere in the outcrop (our observa- tions). Casts and moulds of snails similar to those found at Billa Kalina are also known from Malbooma to the southwest of Billa Kal- ina (Ludbrook, 1980; verified by W.F.P.). At least two other species of presumed Mi- ocene hydrobiids are known from nonmarine limestones in the Northern Territory and west- ern Queensland (one recorded by Mc- Michael, 1968, the other an unpublished ob- servation by W.F.P.) but these do not appear to have any similarity to the mound spring species. There is, as far as we can ascertain, no direct evidence for mound spring activity in the Paleogene, although this is hardly surpris- ing given the climatic, erosional and tectonic changes that have occurred. The unusual fauna that the springs contain does suggest, however, that artesian springs or some equiv- alent habitat, might have been in existence for much of the Tertiary. Early to Middle Tertiary uplift in the Great Divide (Ollier, 1982) on the eastern side of the Great Artesian Basin could have provided the water head neces- sary for spring activity. During the Early and Middle Miocene the vegetation of much of the interior of Australia was dominated by temperate rainforest (Kemp, 1978; Martin, 1978) and the climate was warm and humid (McGowran, 1979). By the Late Miocene to Early Pliocene marked aridity generally correlated to the marine trans- gression (Bowler, 1976, 1982) but it was not until about one million years ago that southern Australia became arid. Periods of wet and dry climates followed four or five times during the last 500,000 years. The climate over the last 400,000 years underwent very large and, per- haps, rapid hydrologic oscillations affecting large areas of the continent (Bowler, 1982). The considerable variation between wet and dry imposed a set of new stresses on habitats and the animals and plants living in them. The main “imprint of aridity on the land- scape” of Australia is of Quaternary age with a peak period about 18-16,000 B.P. (Bowler, 1967, 1982). Nevertheless Bowler (1967, 1982) points out that the trend towards aridity began as early as the Middle Miocene. Kemp (1978) proposed that the climate during the Miocene became increasingly arid in the north and northwest of Australia. The Mi- ocene xerophytic fossil flora from near Billa Kalina supports this hypothesis (Ambrose & Flint, 1981). Thus, although it is possible that adequate freshwater habitats existed in cen- tral Australia up until the formation of the first known mound springs, these habitats would have, presumably, tended to become increas- ingly scarce and reduced in size. If the mound springs were in existence throughout this pe- riod of change they would have provided an aquatic refuge for animals that would other- wise have perished at the first onset of aridity (Ponder, 1986; DeDeckker, 1986). Relationships of mound-spring inverte- brates: The two genera of the Hydrobiidae found in the springs between Marree and Oodnadatta are endemic to these springs. Trochidrobia is not closely related to any known genus and its general relationships are unclear. The other genus, Fonscochlea, is closely related to an undescribed genus in Dalhousie Springs to the north of Oodnadatta, and is a member of the Australasian Hemi- stomia group of genera (Climo, 1974; Ponder, AUSTRALIAN SPRING HYDROBIIDS 91 1982). The female reproductive system and the radular characters of species of Fonscoch- lea set it apart from any others in the group with the exception of the undescribed genus from Dalhousie Springs. The crustacean fauna also contains some endemics of considerable interest. The phreatoicid isopod Phreatomerus latipes (Chilton, 1922) and the ostracode Nagarawa dirga DeDeckker, 1979 (family Cyprididae) both belong in endemic subfamilies. Two ad- ditional endemic ostracodes have been found amongst the material collected on this survey (DeDeckker, pers. comm.). The Phreatoicoidea occur throughout Aus- tralia and are best represented in Tasmania (Williams, 1981). Phreatomerus is probably the least specialized and least typical of the surface-living phreatoicids (Nicholls, 1943) and is the only member of this group known to live in a desert environment. The Cyprididae contain the majority of the nonmarine ostra- codes and have a worldwide distribution. An endemic amphipod is an undescribed species of Austrochiltonia and is morpholog- ically very similar to congeners living in other habitats in South Australia, including hyper- saline environments (W. Zeidler, pers. comm.). A small macrostomid flatworm was discov- ered during the latter part of our study at Eliz- abeth Springs and Old Finniss Springs and is now described (Sluys, 1986). It is one of only two records of this order from Australia. A substantial microfauna and microflora ex- ists, at least in some spring groups, and is largely unstudied (Mitchell, 1985; Ponder, 1986). Evolution of species within mound springs: The mound-springs fauna probably became adapted to living in artesian springs early in its history, given the lack of similar faunas in freshwater ecosystems, including non-arte- sian springs, in central Australia (personal ob- servation, W.F.P.). In addition, the fauna of mound springs does not live in naturally ос- curing water holes, dams or bore drains, with the exception of the old, large artesian bore at Coward Springs railway siding. Springs in the Flinders Ranges have been extensively sam- pled by one of us (W.F.P.) and W. Zeidler, as have the artesian springs to the east of these ranges. No closely related invertebrates have been found in these springs. One of us (W.F.P.) examined the artesian springs in the Queensland part of the Great Artesian Basin and, although some hydrobiids were discov- ered, they are not congeneric with the South Australian species. Their present distribution, which generally coincides with the distribution of the major spring groups (Table 1), suggests that the species had their origin in springs with a sim- ilar grouping to those existing at present. The location of the faults responsible for the cre- ation of many of the springs might have re- sulted in a relatively stable pattern of spring development. There is certainly little evidence to suggest that the groups and complexes of mound springs existing today extended much beyond their present distributions in the re- cent past. Extinct mounds are found in every group but, as far as we know, very few or none are found between them. Small, isolated springs should be ideal hab- itats for speciation, as in the case of the fish fauna of the springs of western North America (Miller, 1950; Turner, 1974; Soltz & Naiman, 1978; Naiman & Soltz, 1981). Migration of small numbers of individuals to such a habitat could, in theory, result in rapid genetic change (Mayr, 1942, 1954; Templeton, 1980). Ac- cording to some workers (e.g., Wright, 1931, 1978; Crow & Kimura, 1970; Cohan, 1984), the subdivision of a population into isolated units will result in genetic differentiation, even in the absence of different selection pres- sures, owing to random genetic drift. Others (e.g., Cain, 1977) have argued strongly against using drift as an explanation as it can- not be proved. Apart from the endemic forms at the well- isolated Emerald and Big Cadnaowie Springs (F. accepta form C and F. zeidleri form B) there is, surprisingly, no observable local en- demism among minor spring groups or iso- lated springs. There is, however, minor differ- entiation between populations, not all of which might have a genetic basis, but this dif- ferentiation is subtle and difficult to measure. Why have these local forms not progressed to the point at which distinct morphological taxa can be recognised and why do other popula- tions not appear to have markedly differenti- ated? Five scenarios are briefly considered below that may account for these observa- tions. First, the mound springs only recently be- came subdivided into groups. Whereas some extinct mounds can be recognised between existing groups of springs, there is little evi- dence to suggest that there was much greater continuity of springs in the recent past (see 92 PONDER, HERSHLER & JENKINS above). Spring formation requires suitable geological conditions, faulting of confining beds or outcropping of aquifer that do not ap- pear to be met in areas outside the present spring groups. Second, there is a high level of gene flow (see Slatkin, 1985, for a recent review) be- tween populations. This might be occurring between populations inhabiting adjacent springs, or even springs in the same group, in a variety of ways. Crossing of outflows during flooding or the accidental transportation on large mammals (including man) and birds as they move from one spring to another are ob- vious ways for snails to be dispersed. Such dispersal, resulting in gene flow, is unlikely, however, between groups separated by more than a few kilometres (e.g., between Wel- come and Davenport Springs, Appendix 1, Figs. 62, 63B) because of the probability of dehydration during transport, as indicated by the desiccation experiments. In addition there are two important steps after the transporta- tion of an individual to a new location: the successful establishment of this individual and then its interbreeding with an individual in that population. While we have no information on migration rates between any springs or spring groups, it seems likely, considering the available dis- persal agents and mechanisms, that there would be a low level of interchange between all but adjacent springs in the same group, but virtually none between groups. A higher level of interchange might be expected to result in the mixing of species between the spring complexes but there is no evidence that this occurs. There might be, however, other rea- sons that such immigration, if it did occur, might fail (see discussion below on commu- nity structure). Dispersal agents are dis- cussed below. Slatkin (1985) points out that differences in levels of gene flow cannot ac- count for morphological stasis and that very low levels of gene flow do not allow the spread of new combinations of genes to other populations (see also the fourth scenario). Another consideration is that the “зирег- population” represented by the spring group, composed of discrete populations in each spring, is probably the level at which evolution is occurring. If the population of a single spring differentiated, the chances of this ge- nome’s being successfully transferred to other populations within the life of the popu- lation might be small, particularly in the case of the relatively unstable sand mound springs and those periodically devastated by floods. Slatkin (1985) points out that the extinction and recolonization of local populations is a form of gene flow and might be more effective than dispersal between established popula- tions in preventing local differentiation. In the third scenario the fauna only recently invaded the springs and is still differentiating. The complexity of the communities, the unique fauna and the existence of probable Pleistocene fossils at Hamilton Hill and the two Beresford Hills are but some of the lines of evidence suggesting that the fauna has some antiquity. It is, however, possible that some of the spring groups might have ac- quired their fauna recently from other, older spring groups. Fourth, genetic variability exists but is not readily observed in the phenotype. Hydrobiid snails are not richly endowed with the kinds of morphological characters that provide clues to minor differentiation. Our measurement data shows that some populations differ sig- nificantly from the rest of the species in one or more characters. Electrophoretic studies might provide useful information about inter- population differentiation but have not been attempted in this study. Phenotypic variation in some populations might possibly have a genetic basis and probable genetic differ- ences occur. For example, a number of albi- nos were observed in a sample from one of the springs in the Elizabeth Springs group but were very rare in other populations. In an- other population from Elizabeth Springs the right tentacle in both sexes was much longer than the left in a high proportion of the sam- ple. These observations suggest that some degree of genetic differentiation exists be- tween populations. Fifth, there is very low genetic variability, i.e. a very stable genotype. Speciation ac- companied by very low levels of genetic di- vergence, as determined by electrophoresis, together with marked phenotypic differences, is known to occur in some desert fishes (Turner, 1974). Turner (1974) suggested that this stability was due to the fact that electro- phoresis samples a portion of the genome coding for a coadapted “core” of enzymes that have not been affected by selective pres- sures in the evolution of allopatric species. There is a large body of data suggesting that the structural genes sampled by electro- phoresis are not the genes involved in the speciation process. In the case of the mound- spring snails, there might be genetic and phe- AUSTRALIAN SPRING HYDROBIIDS 93 notypic stability coupled with low level intra- and interpopulation genetic variability. Ehrlich and Raven (1969) suggest that fail- ure to speciate is not caused by excessive gene flow but by uniform selection regimes over the entire range of the species. The di- versity of spring types and of habitats within the springs, appears, however, to have re- sulted in little ecophenotypic variation (with a few exceptions, see below). Perhaps the hab- itat variation encountered by the snails in any one spring is sufficiently broad and variable to counter the selective pressures associated with local habitat and microclimate differ- ences in different springs. À generalist geno- type might well have considerable selective advantages in such a system. The densities of the snails and other inver- tebrates in many springs can be very high (> 1 million per sq.m. in Blanche Cup Spring) and the total number of snails in any spring of reasonable size could therefore be consider- able. Thus, given these circumstances, the snails inhabiting the average spring cannot be equated with the classic, small population fa- voured by some geneticists as the focal point of evolutionary change. However, when the springs were first colonised, or following an event causing destruction of the majority of the population, the population sizes would have been small and the founder effect (Mayr, 1954) might affect genetic change then (al- though see Barton & Charlesworth, 1984, who have questioned the evolutionary impor- tance of this effect). A rapid increase in num- bers, a stable, generalist genome and no de- viation from the supposedly normal range of environmental parameters would presumably largely negate the potential for a founder ef- fect to operate. In order that some of the above ideas can be tested we put forth two hypotheses. The first of these is that the generally ob- served phenotypic uniformity of tne mound- spring snails throughout their ranges is due to a low level of genotypic variability, with envi- ronmental conditions generally having little ef- fect on the genome. This idea can be readily tested by comparing electrophoretically sev- eral populations within the range of the spe- cies and from different spring types. The second hypothesis is that differentiation between populations is reduced because most populations are large and each is relatively short lived. This can be tested by, first, com- paring the level of genetic difference within a spring group between large populations (in large springs) and small populations (in small springs), second, comparing genetic differ- ences between relatively long-lived springs on hard mounds and short-lived springs on sand mounds and third, comparing genetic differ- ences in populations in old mound springs with those in young springs in the same group. Dispersal: The dispersal mechanisms available to the mound spring aquatic fauna can be divided into three main categories: flood dispersal, transportation by other ani- mals and wind dispersal. Flooding is a periodic occurrence in the study area (Kotwichi, 1986), with, perhaps, a major flood every ten to 25 years and signif- icant local flooding every eight to ten years. Local storms produce local flooding on a smaller scale. There are few data, apart from the rainfall information from Marree and Ood- nadatta, on the detailed rainfall in the area. On a broad scale the direction of flow of the flood channels indicates that flood transpor- tation alone would not account for the present distribution of the hydrobiids. The drainage system cuts across most of the groups of mound springs such that flooding, apart from local transportation within a spring group, would tend to carry organisms away from suit- able habitats rather than to them. Glover and Sim (1978b) believe that fish are primarily dis- tributed by flooding. This might be true for the fish, which are much more mobile than the endemic invertebrates. The fish could pre- sumably survive in Lake Eyre South, when flooded, and reach adjacent drainage chan- nels. The fish are also able to survive in creek-bed pools and bore drains but none of the mound-spring endemic invertebrates ap- pears to be able to do this, with the notable exception of those in the Coward Springs Railway Bore. W. Zeidler (pers. comm.) has found a single specimen of what appears to be the mound-springs Austrochiltonia in Charles Angus Bore near Hermit Hill and an- other solitary individual in Finniss Creek fol- lowing the 1974 floods. These observations might give extra weight to the flood-dispersal hypothesis but do not represent exceptions to the rule that the invertebrate fauna is re- stricted to natural springs. In our view the most important type of dis- persal is accidental transportation by other animals. This type of dispersal has long been known to be important in small, flightless, aquatic animals (see review by Rees, 1965, for examples involving molluscs). Birds are 94 PONDER, HERSHLER & JENKINS the obvious choice for long-distance dis- persal, invertebrates being attached to their feet, legs and feathers as they feed in the springs. Their relatively rapid movement would enable them to transport individuals successfully between springs at least осса- sionally. Ponder (1982) has argued that this method of transportation was the most likely in the establishment of the Lord Howe Island hydrobiid fauna and involved transportation over at least 500 km of ocean. Mammals, such as kangaroos, might also carry inverte- brates from one spring to the other within the same complex. Since the advent of European man, cattle, camels and horses are certainly important in this regard. Man himself would carry living snails in mud attached to his feet; certainly biologists’ boots would be excellent dispersal agents. There are instances in which large aquatic insects, particularly water beetles, have been known to transport mol- luscs but the aquatic insects in the springs in the study area are small. Wind dispersal might be important, al- though we have no data to support this con- tention. Strong winds are common in the area and could disperse animals such as the os- tracodes and snails. It is unlikely that the larger crustaceans and snails would survive such dispersal except over short distances (see results of desiccation experiments for data on snails). The hypothesis that species diversity is sta- bilized as the result of balanced rates of spe- cies immigrations and extinctions (Preston, 1962; MacArthur & Wilson, 1967) has re- ceived strong support. The number of species remains constant but because of extinctions and immigrations the species composition constantly changes. Faeth and Connor (1979) point out that the existence of immi- gration and extinctions resulting in “turnover,” i.e. changes in species composition, while the species number remains constant, is crucial to this theory of “dynamic equilibrium.” It is of interest in this regard to note that the springs within each spring complex have essentially a uniform fauna, the total number of species and the species composition being the same for most springs. If the “dynamic equilibrium” model be accepted for the springs, this uni- formity appears to be in contrast to the obser- vation that there is a low level of interchange between springs. There are, however, differ- ent distributions between spring complexes, suggesting that these major groups of springs can be regarded as archipelagos with very low rates of interchange, whereas spring groups can be regarded as “super islands” on which interchange might be sufficient to main- tain the constant species composition ob- served. Migration into very isolated springs from other springs appears to have occurred in only two cases. Emerald and Big Cadnaowie Springs have, in both cases, only a single snail species (Big Cadnaowie Spring does not have isopods or amphipods) and in both cases the hydrobiids there are clearly derived from species found in other spring groups. This situation appears to meet the predictions of the theory of island biogeography (Mac- Arthur & Wilson, 1967) which state that the effect of area (in this case, size of spring) de- creases as distance from the source areas increases and that islands (i.e. springs) at great distances from species sources will have few species, if any. Environmentally-induced variation: The most obvious variation encountered in the mound-spring snails is the reduction of body size in some populations or parts of popula- tions. Examples are the small form of F. vari- abilis (see discussion under F. variabilis form A) and the stunted forms of F. aquatica, F. conica and F. zeidleri occurring at Kewson Hill (Fig. 53). Fryer et al. (1983) suggest that simulta- neous change in several taxa would be a likely phenotypic response to environmental stress. It is thus likely that attainment of sim- ilar shell forms by the three species of Fons- cochlea in the springs on Kewson Hill are sim- ilar ecophenotypic responses to the same environmental stress, presumably, in this case some factor related to the small, shal- low, steep springs and the lack of shade. It is, however, noteworthy that apparently major differences between the springs (e.g., size of spring, amount of vegetation, substrate type, conductivity; total dissolved solids, pH, slope of outflow, etc.) do not appear to induce marked differences in the phenotype in most instances. An exception to this would be the stunting of some specimens of F. zeidleri in the outflows of several of the taller mounds in the middle group of springs (e.g., Blanche Cup, Horse Springs East). Ecology and behaviour There is evidence, in most springs, of a dif- ference in the relative abundance of the spe- cies found in different zones in the spring. The AUSTRALIAN SPRING HYDROBIIDS 95 (a Aide FIG. 53. Comparison of shell shape between specimens from Kewson Hill Springs (Stn 742, a-c) and Elizabeth Springs (Stn 024, d-f; 767, e). a,d. Fonscochlea zeidleri form A (a, AMS, C.152976; d, AMS, C.152975). b,f. Fonscochlea conica (b, AMS, C.152971; f, AMS, C.152972). c,e. Fonscochlea aquatica cf. form А (с, AMS, C.152973; e, AMS, C.152974). Scale: 1mm; a,c—e Scale A; b,f Scale В. percentage frequency data obtained for a number of springs representing most of the spring complexes is plotted in Fig. 54. This shows that there is a considerable amount of variation between springs, and that in all of the examples and in virtually all of the springs sampled there were substantial differences between the zones sampled, i.e. the head of the spring, the upper outflow and the outflow proper. The difference in habitat preference be- tween F.zeidleri and the large aquatic species of Fonscochlea is illustrated in Fig. 55. These data clearly illustrate that F.zeidleri prefers exposure on the edges of the springs and the large aquatic species prefer submergence. One of the most noticeable aspects of the mound-spring fauna is that it is generally re- stricted to the outflows and spring head; pools and swamps at the base usually contain very low numbers of the spring endemics, with the possible exception of isopods. These lower parts undoubtedly experience the greatest environmental stresses, salinity and temper- 96 PONDER, HERSHLER & JENKINS 100 u o Percentage frequency о Trochidrobia spp « Fonscholea- large aquatic spp . -small aquatic spp ВЕ zeidleri 8 Stations с Transects FIG. 54. Percentage frequencies of hydrobiids in three zones, demonstrating lack of any preference for a particular zone by any of the main aquatic groups, large aquatic Fonscochlea, small aquatic Fonscochlea and Trochidrobia. Data summarized from eight springs. Zone A, head of spring; Zone B, upper part of outflow; Zone C, middle to lower part of outflow. These qualitative samples were taken mainly in the water, hence the low numbers of F. zeidleri in most of the counts. 1, Welcome Springs (756); 2, Old Woman Spring, Hermit Hill (733); 3, Horse Springs East (748); 4, Little Bubbler Spring (744); 5, Julie Springs (772); 6, Strangways Springs (679); 7, Francis Swamp (717); 8, Hawker Springs (670). ature fluctuations, and would be more ephe- meral. Behavioural adaptations and/or physi- ological responses are probably responsible for ensuring that the animals remain in the most favourable parts of the spring but we have little information on the nature of these responses. The information we do have was obtained from the simple physiological exper- iments that were carried out in the field and described above (see physiology section of methods and results). Hydrobiids generally feed by removing from sediment particles bacteria and diatoms that they ingest. The size of the particles has been shown to be correlated with the size of the snail in species of Hydrobia (Fenchel & Ko- foed, 1976). It is possible that a similar rela- tionship will be found in the mound-spring hy- drobiids. We have, at this point, no information on growth rates, fecundity or mortality. Egg cap- sules containing a single egg are laid singly and attached to the substrate or to vegetation. One species of Trochidrobia (T.punicea), places egg capsules in the umbilicus of its shell or (possibly) in that of other individuals of the same species. Mature gonads and the presence of juveniles in samples collected in different seasons suggest that the snails might be reproductively mature all year round. Egg capsule production appears to be low as these are uncommon in samples. Certainly the number of capsules produced in the lab- oratory is very small. Community structure: The general pattern involving the presence of one large aquatic species, the lone amphibious species and one small aquatic species of Fonscochlea, as well as one or sometimes two species of Troch- idrobia in each spring (Table 1) is so well es- tablished that it could be argued that the niche potential of the springs, as far as the hydrobiid snails are concerned, is fully exploited. Fur- ther species packing would presumably in- volve either dietary or microhabitat shifts or AUSTRALIAN SPRING HYDROBIIDS 97 Out of water e e 10 a Percentage frequency In water 100 A A A A A 75 50 25 lo] Stations FIG. 55. Percentage frequencies of Fonscochlea zeidleri form A, closed circles; large aquatic species Fonscochlea accepta and F. aquatica, open triangles, out of, and in, water in five springs. Data from quantitative samples. 1, Welcome Springs (755); 2, Julie Springs (772); 3, Elizabeth Springs (771); 4, Jersey Springs (770); 5, Hawker Springs (670). further reduction or increase in body size. In order that a sufficient size separation be achieved to allow more species to “fit” into the community, the snails would have to reach sizes close to the limits observed in hy- drobiids. With such a tight-knit community structure, the successful introduction of spe- cies from other springs into springs with an established fauna would seem to be unlikely. There are several views on the mainte- nance of species diversity in communities. One school argues that resources are limiting and therefore coexisting species must differ in the utilization of these resources to avoid competitive exclusion (e.g., Roughgarden, 1983). Another school argues that competi- tive exclusion does not occur because densi- ties of dominant potential competitors are kept low by predation or some other form of cropping (Paine, 1966; Connell, 1970), or by environmental disturbance (Connell, 1972; Dayton, 1975). The mound-spring hydrobiids appear to conform, in the main, to the limited resources- species packing model. According to the lim- ited resources school several competing spe- cies can more easily outcompete and eliminate a species than can a single compet- itor (MacArthur, 1972). Thus, with increasing numbers of neighbouring species sharing the same niche space the observed overlap would be expected to decrease (Lande, 1980). Firstly, the snails and other invertebrates often achieve very high densities (> million per sq m in their most favoured areas). Den- sities can be even higher in summer because of increased evaporation causing habitat shrinkage. These high densities suggest to us that competition could be an important factor in this ecosystem. The maximal number of species in any one spring is five, as in Free- ling Springs and some of the northern group of springs, with four being the usual number. 98 PONDER, HERSHLER & JENKINS Generallythere arethree species of Fonscoch- lea and one of Trochidrobia, but Freeling Springs, and some northern springs, have two species of Trochidrobia (Table 1). Because five species can coexist in a few springs, there would appear to be possibilities for further addition of species, at least in Troch- idrobia, in other springs south of Freeling Springs, which have only one species of this genus. This addition has indeed occurred, one of the Freeling Spring species (T.minuta) being found in the closest springs. The rea- son that T. minuta is absent from the other springs is not clear, but a recent dispersal event is, in our opinion, the most likely hy- pothesis. If this be the case, detailed studies on the interactions between the two Troch- idrobia species in these springs would be of considerable interest. Presumably the Freeling fauna evolved in greater isolation than prevails today, allowing the evolution of the endemics that this group of springs contains. The two species of Troch- idrobia were presumably allopatric and, when included together in the same system, previ- ous divergence in size or in behaviour might have been accentuated, allowing the coexis- tence of these species. Trochidrobia punicea and T.smithi are similar in size to each other and there do not appear to be any noticeable differences in habitat preference between them. These factors suggest that the long- term coexistence of T.punicea and T.smithi following an introduction would be unlikely, following the competitive exclusion principle (Gauss, 1934; Lack, 1947). This principle has, however, been questioned by some workers (e.g., Ayala, 1970) who argue that competing species can coexist even with lim- ited resources. The widely divergent repro- ductive anatomy in these two otherwise al- most indistinguishable species is difficult to explain without invoking a past sympatry. Per- haps they were sympatric in an environment in which resources were not limited or in which they were separated ecologically. It is possible that such coexistence is indeed oc- curring now, as species determinations have been made by dissecting only a small number of specimens from each locality. Interaction between the small species of Fonscochlea and species of Trochidrobia might be avoided by subtly different choices of habitat. Preliminary analysis of the distribu- tion of the snails in the springs shows that they are distributed differently, although with some overlap. Percentage frequency data of snails in various zones within the springs sug- gest that springs that have fewer species show less zonation in the fauna, thus favour- ing the idea that the observed distributions are the result of interaction between species. A third possibility, differential mortality, seems unlikely. Differences in body size allowing differing use of limiting resources, such as food and shelter, are one way in which competition be- tween sympatric species might be reduced (Hutchinson, 1959; Fenchel, 1975; Roth, 1981; Williams, 1972). Whenever size differ- ences do not occur the species must differ in other ecological dimensions. The species of Fonscochlea are separated into two size groups, one consisting of F.accepta, F.aquat- ica and F.zeidleri, the other, smaller in size, consisting of F.variabilis, F.billakalina and F.conica (Table 17). Likewise, the two sym- patric species of Trochidrobia at Freeling Springs show a marked difference in size (Table 17), although the size difference is not so large as in the species of Fonscochlea. This difference is even less between the sym- patric species of Trochidrobia in the northern springs. These species seem to predominate in different parts of the outflow, thereby prob- ably reducing the level of interspecific inter- action. One weakness in this model is that juveniles of the larger species would obvi- ously overlap with the small species, although this would not be significant if the juveniles reached maturity quickly and the adults were long-lived. Unfortunately we lack growth rate and lifespan даа. Fenchel’s (1975) demon- stration of displacement in size in two sym- patric species of Hydrobia has been con- tested by more recent work (Roth, 1981; Simberloff & Boecklen, 1981; Levinton, 1982; Cherrill & James, 1987). Some indirect evi- dence indicating size displacement was ob- tained in a study of the hydrobiids of Lord Howe Island (Ponder, 1982). Variation in environmental factors might allow a greater species diversity {Пап would a system that is stable and shows little or no variation (Levins, 1979). The large species of Fonscochlea are separated ecologically whenever they occur together, as F. zeidleri is amphibious and lives in the same spring with only one of the other large species that is aquatic. As noted above, the habitat separa- tion of these two species was very noticeable in all of the springs examined (Fig. 55). Atthe Coward Springs Railway Bore, in which F.aquatica is not found, the normally amphib- AUSTRALIAN SPRING HYDROBIIDS 99 TABLE 17. Comparison of shell heights and ratios of shell heights for pairs of sympatric congeners. Species Station F. accepta form A Thats) F. conica 003 F. aquatica form A 739 F. variabilis form A F. aquatica form A 032-033 Е. variabilis form В Е. адиайса form A 679 F. billakalina F. aquatica form A 764,020 F. conica F. aquatica form B 045,046 F. variabilis form C 665 T. inflata 043 T. minuta 045 ious F. zeidleri lives both on the edges and in the water to a depth of several centimeters. Species inthe second group, the small spe- cies, have never been found in the same spring, although they do live in closely adja- cent springs т the Blanche Cup complex, and are markedly different in size from the larger aquatic species sharing the spring. Predation does not appear to be significant in determining the densities of the aquatic in- vertebrates in the springs. Predation by birds might occur, but we know of no other potential predators apart from small mammals and rep- tiles. Predation from all of these sources would, however, be at a low level, given the small numbers of these animals in the vicinity of the springs. Birds have regularly been ob- served feeding on the springtails where the endemic invertebrates are normally rare or absent but aquatic insects are common. They are rarely seen feeding in the outflows in which the endemic invertebrates are abun- dant. The fishes in the springs do not appear normally to eat the snails, their gut contents being mostly vegetable matter, snails only rarely being found (J. Glover, pers. comm.). There is, in the mound springs, marked di- urnal and seasonal variation in temperature (Ponder, 1986; Figs. 3, 50), some variation in rates of flow (from observation), evaporation (and hence salinity) and, presumably, algal Shell Height (mm) x S X(large)/X(smaller) 3.43 0.17 1.92 1.79 0.16 3.16 0.15 1.48 2.14 0.13 4.31 0.17 1.92 2.25 0.21 4.24 0.18 1.47 2.88 0.28 3.96 0.27 1.45 2713 0.15 3.93 0.18 1.80 2.18 0.24 3.88 0.15 1.41 2715 0.34 4.23 0.22 107 2.69 0.21 1.49 0.16 1535 1.10 0.06 cover etc., as well as spatial variation in sub- strate, slope, vegetation, water flow and depth within and between springs. Although this heterogeneity is a characteristic feature of the springs, this ecosystem, compared with many other aquatic ecosystems, particularly in arid environments, is probably a relatively uniform one (Naiman, 1981). Any analysis of the niche limitations of individual species would have to take account of these temporal oscillations and the spatial complexity. In ad- dition, destruction of part of the population can occur from sudden changes in flow rate and/or unusually high evaporation, leaving all or part of the outflow dry. Trampling by ani- mals not only reduces numbers indiscrimi- nately (although, perhaps, favouring species living beneath rock), but also results in tem- porary habitat destruction. Floods also have a devastating effect on springs in water courses, as observed at the Hermit Hill com- plex following the January, 1984, floods. An analysis involving all of these variables is well beyond the scope of this paper. It could be inferred, however, that this ecological variabil- ity might be a contributing factor in allowing a rather high number of closely similar species to coexist. Indeed it is very unusual to have three sympatric congeners of hydrobiids. It might also be suggested that, if instability were shown to be a major feature of the 100 PONDER, HERSHLER & JENKINS mound spring ecosystem, niche separation might be important only in times of over- crowding or of critically limited resources. We favour this marriage of the two views on the maintenance of species diversity. Physiology The mound-spring habitats are generally small and subject to harsh and highly variable climate: temperatures in the area frequently fall below 0° C in winter and surpass 40° C in summer, and rainfall is scant and variable. The springs contain hard water that is slightly saline (2—8%.) but with the high evaporation encountered, locally salinities probably ex- ceed this range. Given these conditions, one would predict that mound-spring snails would be fairly tolerant to a range of temperatures and salinities, as well as to desiccation and, possibly, to deoxygenated water. Species should vary in their tolerances to these vari- ables, as well as in their responses to light and submergence in water, according to their microhabitat and, possibly, body size. In par- ticular, the amphibious snail species should be more tolerant than the aquatic species to desiccation. The ability to withstand desicca- tion has important implications for their poten- tial to survive dispersal and temporary cessa- tion of water flow. The experiments described above were carried out in an attempt to gain an under- standing of the responses of hydrobiids to some of the important environmental param- eters encountered in the mound springs. The purposes of these experiments were first, to provide data on the tolerance of the mound spring hydrobiids to desiccation, salinity, deoxygenated water, temperature, and sub- mergence in water; and the response of the: snails to light and submergence in water; sec- ond, to discuss these data as they relate to the ecology of the snails; and third, to com- pare the results of these experiments with similar studies of other hydrobiids. Similar ex- periments were also carried out on the en- demic isopod and amphipod; a summary of the results is given in Kinhill-Stearns (1984). The results of the physiological experi- ments indicate that there are significant differ- ences among species, and among some pop- ulations, in tolerance and response to the environmental parameters studied. Many of these differences appear to be related to the ecology and/or the body size of the snails. The primary ecological division of the mound spring snails is into amphibious (F. zeidleri) and aquatic species (all others) (Fig. 56). Fonscochlea zeidleri typically inhabits the narrow band of moist habitat on the sides of an outflow or surrounding a spring pool. At most localities, more than 80% of living F. zeid- leri are found out of the water and the reverse is true of the aquatic species (Fig. 55). The exception is at Coward Springs Railway Bore in which a substantial part of the population of F. zeidleri is fully aquatic. We have noted three possible morphologi- cal adaptations of F. zeidleri to the amphibi- ous habit. The cephalic tentacles, typically elongate in the aquatic species, and in most hydrobiids, are short relative to those of the other species. Observations of F. zeidleri crawling in a film of water indicated that their short tentacles were maintained in approxi- mately their normal position, oriented about 45° to the longitudinal axis of the snout, whereas under similar conditions the tenta- cles of F. aquatica were bent backwards by the surface tension. Thus the shortened ten- tacles of F. zeidleri might have adaptive value whenever the snail is crawling about in a thin film of water, the forward-pointing tentacles being able to maintain their sensory function in the region lateral to the anterior end of the snout. The calcareous opercular pegs, which are small to almost absent in the aquatic spe- cies, are massive in F. zeidleri, providing a relatively large muscle attachment area that presumably enables the operculum to be held tightly against the aperture whenever the Snail is retracted into the shell, and thus help resist desiccation. The gill filaments are fewer, shorter, and thicker relative to body size than those of the aquatic species. When- ever a Snail is out of the water it is likely that the pallial cavity will contain air bubbles as well as water. Such air bubbles could abut against long gill filaments, and cause them to fold over, which folding would inhibit the lat- eral ciliary activity and hence the flow of water through the mantle cavity, and, consequently, interfere with respiratory activity. It is less likely that the air bubbles would so affect the shortened, stubby filaments of F. zeidleri. Also note that an air bubble held in a damp mantle cavity could also assist in maintaining a lower body temperature compared to snails with a water-filled cavity. This has been found to be the case in experiments with land snails (Schmidt-Nielsen et al., 1972). As predicted, F. zeidleri in all three populations tested had a significantly higher tolerance to desiccation AUSTRALIAN SPRING HYDROBIIDS 101 Imm amphibious F.zeidleri F.z. form B F.aquatica aquatic F billakalina F.accepta F.variabilis F.conica (Wolfgangia) El (Fonscochlea) decreasing size — FIG. 56. Diagrammatic representation of probable relationships of species of Fonscochlea, as well as sizes and habitats. This figure is not a cladogram and the distances between branches are not intended to indicate degree of taxonomic separation. than had the aquatic species tested. Apart from F. zeidleri, only F. aquatica from the small, harsh Kewson Hill springs survived for 48 hours in the dry dishes. Considering their amphibious habit, it was not surprising that, for two of three popula- tions, large percentages of F. zeidleri crawled out of the water in the submergence prefer- ence experiments. While large numbers of snails of some of the aquatic species also crawled to the tops of the dishes, they did not venture beyond the meniscus and remained at least partly submerged. The differences in results between popula- tions of F. zeidleri in the submergence pref- erence and light response experiments can be explained partly by differences in micro- habitat of these populations. Blanche Cup is a 102 PONDER, HERSHLER & JENKINS large calcrete mound, with a spring pool on top and outflow to one side. Fonscochlea zeid- leri lives there on moistened rock, and most of the individuals are fully exposed to the sun. At Finniss Springs, the mound is soft, being composed of a sandy substrate, allowing the snails to burrow to shallow depths. The pop- ulation of F. zeidleri at the Coward Springs Railway Bore has been introduced, presum- ably recently, from a nearby spring, but F. aquatica has not been introduced in the 80— 90 years that the bore has been flowing. Fons- cochlea zeidleri occupies both the amphibi- ous and aquatic microhabitats at this locality, possibly because F. aquatica, which is similar in size to F. zeidleri, is absent. The specimens on which the experiments were conducted were all submerged when collected. These microhabitat differences correlated well with the results of the submergence preference experiments. Over 50% of F. zeidleri from Blanche Cup and Finniss Springs crawled out of the water in these experiments, but only 16% of the snails from Coward Springs Rail- way Bore did so. Despite its reduced ctenidium, F. zeidleri did not show significantly higher mortality or reduction in activity than did the aquatic spe- cies during the experiments on tolerance to deoxygenated water and submergence. In the controls of the deoxygenation experiment, too, the activity of F. zeidleri did not decrease faster than that of the aquatic species. This fact might suggest that the differences ob- served in the ecology of these snails might not be due soley to simple physiological lim- itations, at least in the ability of F. zeidleri to tolerate a submerged existence. Certainly the existence of an aquatic population at Coward Springs Railway Bore would support this ob- servation. Given the variation seen amongst runs of F. zeidleri from Coward Springs Railway Bore and Finniss Springs, it is difficult to generalize as to the response of these snails to light. One possible explanation for the variable re- sults is that the snails from these populations are adapted to avoid light in their natural hab- itats, as their microhabitat distribution would suggest, but while held in sunlight-exposed containers, the snails used in one of the runs might have become light adapted and hence did not avoid light during the experiment. It is also possible that the snails used for the sep- arate runs were collected from slightly differ- ent habitat types. The Blanche Cup popula- tion of F. zeidleri lives exposed to the sunlight, but only 41% of the snails tested for this pop- ulation were in the light zones. The two similar-sized forms of F. accepta differ in the height of the gill filaments; F. ac- cepta form B has shortened gill filaments, similar to those of F. zeidleri, whereas F. ac- cepta form A has tall filaments like those of F. aquatica. Their habitats are generally similar as both species are abundant in shallow wa- ters in outflows, but F. accepta form A is com- monly found in deeper pools as well, whereas F. accepta form B does not seem to prefer this habitat. As might be predicted from their morphology, F. accepta form B survived bet- ter than did F. accepta form A during the des- iccation experiments. Trochidrobia punicea is often found on ex- posed surfaces in the water whereas most of the other aquatic species seem to prefer shaded microhabitats. This difference cor- responds well with the fact that T. punicea was the only species tested that had a strongly positive response to light. The aquatic Fonscochlea species, however, are also frequently encountered in the open, often in large numbers, but were negatively photo- tropic in the experiments. Their natural oc- curence might be due, in part, to the lack of suitable shelter. The tolerances of the various species to desiccation and salinity might be determined, in part, by body size. Desiccation rate is partly a function of exposed surface area of tissue. When retracted in the shell, a snail can lose water either through the shell or through, or around the edges of, the operculum. A small snail has larger ratios of shell surface area to shell volume and shell apertural area to shell volume than has a large snail of similar shell geometry. Small snails therefore should des- iccate more rapidly than large snails. This would be accentuated by the fact that, for the mound-spring snails, small snails have thinner shells than do large snails. The desiccation experiments clearly showed that the large- sized species, apart from F. accepta form A (see above), had higher survival in the dry dishes than did the small-sized species (T. punicea, F. variabilis, F. conica). As noted above, these differences obviously are at least partly due to divergent adaptation as well. Salinity tolerance was also correlated with body size among the species tested. The large species were fully active in 12% salt water whereas the small species had reduced activity in 9%o and no activity in 12%o. It is not clear the extent to which body size itself is AUSTRALIAN SPRING HYDROBIIDS 103 responsible for these differences. Although osmotic problems of water loss and salt up- take encountered in high-salinity water are again dependent on surface area, and hence related to body size, physiological adapta- tions might be more important. The maximal salinity known for the spring groups from which the snails were collected for these ex- periments is about 4.5%. and about 5.2% for springs known to contain hydrobiids (Kinhill- Stearns, 1984). It is noteworthy that the snails can tolerate salinities that are twice this value. The mound-spring snails are members of a large group of freshwater animals that can tol- erate salinities of approximately 3-10%o (Bayly, 1972). As discussed below, their sa- linity tolerances do not approach those of the inhabitants of athalassic nonmarine waters (salinity of 10-300%., sensu Bayly, 1972). К would be of great interest to compare the tolerances of mound-spring snails to temper- ature, salinity, and water oxygenation with fluctuations of these parameters within the springs from which the snails came. Unfortu- nately such habitat data are not generally available, although we do have some data concerning temperature. For an 11-day pe- riod during winter, beginning 26/8/83, the temperature in one of the largest of the Fin- niss Springs varied from 11.0-27.8°C. just below the springhead, and from 13.0- 31.0° С. in a downstream pool. The air tem- perature varied from 3.0-36.0° С. during the same period. Maximal diurnal fluctuations were 16.1° near the springhead and 15° in the downstream pool, values approaching the maximal such fluctuations recorded in desert aquatic habitats (Deacon & Minckley, 1974; Hershler, 1984). An aspect of snail morphology that might bear on thermal tolerance is body pigmenta- tion. In most of the populations of mound- spring snails the degree of pigmentation of the head/foot is highly variable but some con- spicuous trends have been observed. In gen- eral, there is an increase in black pigment (melanin?) in populations inhabiting the most exposed habitats (e.g., Kewson Hill) where shelter (e.g., vegetation) is virtually absent. Individuals exposed on hard rock outflows tend to be darker than those that can gain shelter by burrowing in the sand. This color- ation does not appear to be in any way cryptic because in many outflows the dark snails are very conspicuous against the pale sediment or rock. Hydrobiids living in caves and other phreatic habitats are always unpigmented (Vandel, 1965), whereas species living in surficial waters are often pigmented, usually black. This pattern, together with our obser- vations on the pigmentation of mound-spring snails, suggests that the degree of pigmenta- tion is correlated with exposure to sunlight. As the pigment in the mound spring snails is largely restricted to the upper visceral mass (including the gonad), head/foot and snout, areas that are exposed to the sunlight, and hence ultraviolet rays, it is likely that such pig- ment has a screening function in this group. While there are no data available on toler- ance to environmental parameters in other spring-dwelling hydrobiids, some data are available for species in the related family Po- matiopsidae, which inhabit ephemeral water bodies in arid lands (Coxiella in Australia, Tomichia in Africa) (Bayly & Williams, 1966; DeDeckker & Geddes, 1980; Davis, 1981), and moist amphibious habitats in non-arid re- gions (Oncomelania in Asia, Pomatiopsis in North America) (van der Schalie & Getz, 1963). Some information is also available for hydrobiids of brackish waters (Hydrobia, Pot- amopyrgus) (Newell, 1964; Avens, 1965; Winterbourn, 1970; Bayly, 1972; Fenchel, 1975; Wells, 1978). These various data sets can be compared only in a general fashion because of differences in experimental de- sign and methods. Tomichia and Coxiella typically tolerate at least several months of desiccation, and a 10 to 20-fold change in water salinity. These tol- erances are considerably broader than those of the mound-spring hydrobiids, although the desiccation tolerance of Fonscochlea zeidleri can approach that of the permanent stream- dwelling Tomichia differens (Davis, 1981). Such broad tolerances are expected, consid- ering the typical habitats of Tomichia and Coxiella, ephemeral water bodies subject to extreme salinity fluctuations. The mound- spring habitat, while often quite shallow, is permanent and not subject to great salinity fluctuations. Fonscochlea zeidleri does not occupy dry habitats, nor do any of the mound- spring snails inhabit downstream pools, pos- sibly because they might be subject to high temperature and salinity fluctuations and might even dry up in summer. Pomatiopsis and Oncomelania appear to have tempera- ture tolerances slightly broader than those of the mound spring snails. While Fonscochlea zeidleri had no mortality after submersion for 72 hours, there was significant mortality after 104 PONDER, HERSHLER & JENKINS this lapse of time in some of the species of Oncomelania and Pomatiopsis, perhaps re- flecting more specialization for a terrestrial ex- istence in the latter group. Most of the species of Oncomelania and Pomatiopsis tested ap- pear to survive desiccation better than do F. zeidleri, again implying more specialization for near-terrestrial life. After 48 hours in dry dishes, there was mortality in F. zeidleri whereas there was 100% survival in all spe- cies of Pomatiopsis and Oncomelania. While it is unlikely that F. zeidleri would survive 30 or 42 days in dry dishes, it might well survive a week and therefore be as tolerant to desic- cation as Pomatiopsis cincinnatiensis. Hydrobia totteni and the mound-spring hy- drobiids were active throughout a similar range of temperatures. The Hydrobia and Potamopyrgus species tested had high per- centages of snails active in a range of salini- ties exceeding 17%. and as much as 33% (Winterbourn, 1970), whereas the mound spring snails were active throughout a salinity range of only 12 0/00. This difference is prob- ably a reflection of the estuarine habitat of Hydrobia and Potamopyrgus. Fonscochlea zeidleri, but not the other mound-spring spe- cies, appears to have a higher tolerance to desiccation than has Potamopyrgus (an aver- age of 73% survival versus 0% survival in dry dishes after 48 hours) and possibly Hydrobia totteni, but probably not H. ulvae. Obviously the estuarine Hydrobia would not be exposed to the semi-dry conditions that F. zeidleri ex- periences for more than the length of a tidal cycle. Fish and Fish (1977) have shown that the embryonic development of Hydrobia ul- vae has an optimal temperature/salinity com- bination. At temperature/salinity combinations differing from the optimum, hatching was pro- longed and mortality increased. It is probable that temperature and salinity changes in the mound springs have similar effects on the de- velopment of the hydrobiid eggs. Hydrobiid fauna The discussion thus far has concentrated on the general problems and theoretical con- siderations concerning the fauna as a whole. A scenario is suggested within the framework proposed above to provide an explanation for the differentiation of the taxa. The mound springs provide a gradation of degrees of isolation from completely isolated, through single springs, to local spring groups with scattered to interconnected springs. Any hypothesis that attempts to explain the evo- lution of a taxon only in terms of the details of present-day spring distribution would be inad- equate but, as suggested above, the general pattern of spring distribution is likely to be fairly stable. Obviously any links between, or greater isolation of, present groups would have been of significance. Other past events that might have been important in the devel- opment of the present-day taxa are changes in climate, drainage patterns and, possibly, different ecological and physiological require- ments of the hydrobiid fauna, perhaps en- abling some of the species to live in other water bodies. This last possibility we consider unlikely and, consequently, do not develop it further. A possible exception is the amphipod, Austrochiltonia, which might have invaded the springs recently from other water bodies, closely similar species being found farther south. The sympatric species of snails occurring in the majority of the springs represent four ra- diations. One radiation is that of Trochidrobia with two very distinct sympatric species at Freeling Springs, one of which is endemic and the other, as noted above, also found in some of the northern springs to the south of Freeling Springs, and two morphologically similar, allopatric species in the other springs. Fonscochlea (Fig. 56) has radiated in two main directions, one toward an amphibious species, F. zeidleri from which the aquatic form, F. zeidleri form B, is secondarily de- rived, and the other, probably less derived, including all the other taxa. These groupings are reflected in the subgeneric classification. The larger, aquatic group split into two groups that radiated in parallel with each other but differ markedly in size. The species in these two “aquatic” radiations are very similar mor- phologically and differ from F. zeidleri in a number of important characters. It is thus likely that the two subgenera in Fonscochlea represent an ancient speciation. The species distributions within the radiations follow the existing pattern of springs closely enough to indicate that the speciation events are similar in antiquity to the present major spring groups. There are several patterns of distribution demonstrated by the mound-spring hydrobi- ids (Figs. 13, 26, 31, 39; Appendix 1, Figs. 57-63; Table 1). These fall into three main groups. The first pattern is restriction to a sin- gle spring. This applies to only two infraspe- cific forms (F. zeidleri form B not included in AUSTRALIAN SPRING HYDROBIIDS 105 distribution maps but occurring at Big Cad- naowie Spring, Fig. 63A; and F.accepta form C, Fig. 13). The evolution of both of these forms is presumably quite recent as they are not greatly differentiated from related taxa. They presumably differentiated in isolation af- ter dispersal, or might be relictual popula- tions. The second pattern is restriction to a single spring group or complex. Three of the taxa occurring at Freeling Springs (Fig. 58), T. in- flata, Е. aquatica form В and F. variabilis form C fall into this category, as do F.accepta form B (Fig. 13) and F.variabilis form A (Fig. 26). The “taxa” of Fonscochlea in this category are considered to be of infraspecific status only, i.e. “forms” that might be subspecies, and their relatively recent divergence is prob- able. Whether these forms represent differen- tiation following dispersal or the partial frag- mentation of a wider-ranging taxon following greater isolation of spring groups, is unclear. The two species of Trochidrobia found at Freeling Springs are, on the other hand, very different from their congeners and no close relatives occur elsewhere, facts suggesting a considerable period of isolation and continuity with the ancient spring habitat of a group dif- ferent from the rest of the mound springs. If this were indeed the case, the endemic forms of Fonscochlea found at Freeling Springs would probably be of relatively recent origin and derived from the springs to the south. The occurrence of T.minuta in some of the north- ern springs might be due to recent dispersal events. The third pattern is occurrence in several spring complexes. The majority of taxa, in- cluding geographic forms, fall into this cate- gory. Fonscochlea accepta form A (Fig. 13) is found in Welcome and Davenport Springs (Figs. 62, 63B), whereas the species (F. ac- cepta) ranges from Welcome to Emerald Springs, a range of about 82 km (Figs. 13, 61, 63B). Fonscochlea aquatica form A ranges through the Blanche Cup group to the north- ern springs south of Freeling Springs (165 km range) (Figs. 13, 61, 63B), with a closely re- lated form (Subspecies?) in Freeling Springs (Figs. 13, 58). The amphibious F.zeidleri form A has the largest range of any species (270 km) and is found from Freeling Springs to Welcome Springs (Figs. 31, 58, 63B). One of the smaller species of Fonscochlea, F. vari- abilis, has differentiated into what we are re- garding as forms but which might well be equivalent to subspecific taxa. One form is found in the scattered northern springs, an- other even farther north in Freeling Springs (Fig. 58), and another in the Blanche Cup spring group (Figs. 26, 61). Fonscochlea con- ica, on the other hand, while showing some morphological variation, ranges from Beres- ford Spring to Welcome Springs (124 km) (Figs. 26, 61, 63B). Fonscochlea billakalina ranges through the Billa Kalina-Francis Swamp-Strangways spring complexes (Figs. 26, 60, 61). The two species of Trochidrobia that occur in the springs south of Freeling Springs are distributed differently from the Fonscochlea species (Table 1; Fig. 39). Troch- idrobia smithi extends from the northern springs to the Billa Kalina complex and the Beresford group (Figs. 60, 61). Trochidrobia punicea, \ike F.conica, is found in the middle springs and extends to Welcome Springs (Fig. 63B) but, unlike that species, is found in most of the springs in the area. The different distributions of the larger aquatic species of Fonscochlea, F. accepta and F. aquatica, compared with T. punicea and F.conica suggest that there might have been an extinction of the fauna in the middle springs followed by the differential invasion of F.aquatica form A and F. variabilis from the northern springs and T.punicea and F.conica from the south. It is possible that the original population of F. aquatica in the area is still represented by at least some of the popula- tions in the Jersey-Elizabeth-Kewson Hill Springs area (Fig. 61), as these appear to have differentiated (see discussion in taxo- nomic section under F. aquatica form A). Fons- cochlea variabilis has been successful in es- tablishing itself only in the larger springs in the Blanche Cup spring group (Fig. 61) whereas the very similar F.conica occurs throughout the rest of the middle group. This hypothesis would also help to explain the lack of notice- able differentiation in the species found in the middle spring group, with the exception of F.variabilis form A. Fossil specimens from the middle of the area (from the top of Hamilton Hill, Fig. 61) include only F.zeidleri and a spe- cies of Trochidrobia that could be either T.smithi or T.punicea, whereas small-sized Fonscochlea are abundant on North Beres- ford Hill (Fig. 60), a similar fossil mound on the northwest edge of the middle springs. Absence of fauna Several springs and groups of springs in the study area did not contain hydrobiids (Ap- pendix 1) and many of these same springs 106 PONDER, HERSHLER & JENKINS also lacked the endemic crustaceans. Individ- ual springs in some spring groups also lacked the snails and crustaceans whereas neigh- bouring springs did not. Water chemistry does not appear to explain the absence of fauna in many cases (see Kinhill-Stearns, 1984, for details of water chemistry of most of the rel- evant springs), although poor water quality and the lack of running, oxygenated water is certainly relevant in some cases. At least two springs, Pigeon Hill Spring and Dead Boy Spring in the Hermit Hill Spring Complex (Fig. 62), are closely associated with fauna- bearing springs but have sulphate-rich water that renders them unsuitable for the mound- spring invertebrates. Several springs along the southern edge of Lake Eyre South (Jacobs, Fred, Smiths, Gosse and McLachlan, Fig. 62) are similar in water chemistry to the Hermit Hill springs and, at least in most cases, have potentially good habitat available. The invertebrates do not ap- pear to have become established in these springs in the recent past as there were no traces of snail shells in the spring sediments. Flooding in this area results in the submer- gence of many of these springs (our observa- tions and C. Woolard, pers. comm., based on the Jan. 1984, floods) and it seems likely that even if one of the invertebrates were осса- sionally introduced naturally and if a popula- tion were established, it would not be suc- cessful in the long term. Some of the smaller, more isolated springs might never have achieved a successful introduction or, per- haps, because of their small size, are much more susceptible to devastating stock dam- age or occasional natural fluctuations in flow which might obliterate the habitat. Conservation The importance of the mound springs as unique natural ecosystems that contain a va- riety of endemic biota has been addressed elsewhere (Casperton, 1979; Mitchell, 1980, 1985; Harris, 1981; Kinhill-Stearns, 1984; Ferguson, 1985; Ponder, 1985, 1986). The fragility of these ecosystems, their suscepti- bility to damage by livestock and, particularly, the real probability of their extinction as a re- sult of the extraction of larger amounts of ar- tesian water from the aquifers of the Great Artesian Basin, would suggest that special provisions for their maintenance are required. To date none of the springs of the Lake Eyre Supergroup that contain endemic fauna is of- fered special protection apart from a few springs that recently have been fenced to pre- vent stock damage. ACKNOWLEDGMENTS This project would never had started with- out the enthusiasm and support of Wolfgang Zeidler of the South Australian Museum. We thank him for this and for his help and com- pany in the field. We also thank D. Winn, D. Bushell, J. Ponder, W. Ponder Jnr, С. Wool- ard and E. Hershler for their assistance in the field. Мг. О. Beechey assisted greatly with the computer analyses and Miss $. Yom-Tov as- sisted with the development of the programs used in the data processing on the microcom- puter. D. Winn, J. Gillespie, M. Fletcher, S. Carter, G. Clark, J. Howarth and the late J. Kerslake assisted in the preparation of this paper. A grant from the South Australian Gov- ernment and financial assistance from Roxby Management Services (RMS) assisted great- ly with this project and provided a salary for one of us (R.H.). Considerable additional sup- port has been provided by ARGS grants (grant numbers D17815182, D18516186) and support from the Australian Museum Trust. 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Additional chemical and flow data are given by Kinhill-Stearns (1984) for many of the springs listed. The collectors and the date of collection are given as are brief details about the substations. The numbers in brack- ets following the substation data for some of the Southern Springs are the numbers allo- cated to these springs by Roxby Management Services during their survey. Full data about each station are not given. Generally informa- tion on the dimensions of the spring, the sub- strate, habitat, vegetation cover, condition, and details of the substations were noted for each station. In many temperature and, in some, pH, were recorded. Abbreviations used: BJ—B. Jenkins, CW—C. Woolard, DB—D. Bushell, DW—D. Winn, EH—E. Hershler, helic—helicopter, RH—R. Hershler, WP—W. Ponder, WPj—W. Ponder Jnr, WZ—W. Zeidler. 002 (=41) Welcome Springs-northern one. 29°40.09'S, 137°44’E. Curdimurka 594324 (Cobb, 1975:1). Coll. WZ, 10 Sept.81. General. 003 (=42) Welcome Springs-southwest. 29°40.77'S, 137°49.75'E. Curdimurka 594324. (Cobb, 1975:1). Coll. WZ, 11 Sept.81. General. 004 (=49A) Davenport Springs. 29°40.09'S, 137°35.31'E. Curdimurka 567325. (Cobb, 1975: 11). Coll. WP, WZ and BJ. 13 May 81. General. 005 (49B) Davenport Springs. 29°40.09’S, 137°35.56’E. Curdimurka 567325. (Cobb, 1975: 11). Coll. WP, WZ, WPj and BJ, 13 May 81. Gen- eral. 006 (=71) Mount Hamilton Homestead ruins. 29°29.71'S, 136°53.95’E. Curdimurka 496346. Coll. WP, WZ, BJ and WPj, 16 May 81. Pool at top. 007 (=69) Strangways Spring, E. of Blanche Cup. 29°29.06'5, 136°53.64’E. Curdimurka 495357. Coll. WP, WZ, BJ and WPj, 16 May 81. Upper part of outflow. 008-012 (=65) Blanche Cup Spring. 29°27.35'$, 136°51.57'E. Curdimurka 491351 (Cobb, 1975:51). Coll. WP, WZ, BJ and WP), 15 May 81. 008: In pool. 009: Upper outflow. 010: Middle outflow. 011: Out- flow at base of mound. 012: Near end of outflow. 013-017 (=66) The Bubbler Spring. 29°26.8'S, 136°51.4’E. Curdimurka 492352 (Cobb, 1975:49). Coll. WP, WZ, BJ and WPj, 15 May 81. 013: Upper outflow, just below pool. 014: Lower outflow. 015: Swampy pool at base. 016: In seep on edge of pool at top. 017: On sedges and algae in pool at top. 018 (=63) Coward Springs Railway Bore. 29°24.21'S, 136°48.89'E. Curdimurka 357486. Coll. WP, WZ, BJ and WPj, 15 May 81. General. 019-022 (=64) Coward Springs. 29°24.78’S, 136°47.28'E. Curdimurka 484357 (Cobb, 1975:56). Coll. WP, WZ, BJ and WPj, 15 May 81. 019: Pool at top. 020: Upper outflow. 021: Outflow near base of mound. 022: Lower outflow. 023 (=64E) Coward Springs. 29°24.78'S, 136°47.28’E. Curdimurka 484357 (Cobb, 1975:56). Coll. WP, WZ, BJ and WPj, 15 May 81. Separate seepage at top of mound. 024 (=52) Elizabeth Springs. 29°21.36’S, 136°46.30’E. Curdimurka 482363. (Cobb, 1975:59). Coll. WP, WZ, BJ and WPj, 14 May 81. General. 025 (=60) Jersey Spring. 29°20.81'S, 136°45.37'E. Curdimurka 481364. Coll. WP, WZ, BJ and WPj, 15 May 81. General. 026-027 (=53) Old Billa Ката Spring. 29°27.66'S, 136°29.75’E. Billa Kalina 453350. Coll. WP, WZ, BJ and WPj, 14 May 81. 026: Top of outflow. 027: Lower outflow. 028 (=75) Beresford Spring (N. side of Beresford Hill). 29°16.0’$, 136°39.7'E. Curdimurka 471374 (Cobb, 1975:65). Coll. WZ, 10 Sept. 81. Near top of outflow. 029-030 (=76) Strangways Springs (near Irrapa- tana). 29°09.9'S, 136°33.1’E. Curdimurka 458387 (Cobb, 1975:68, Williams, 1979:64). Coll. WZ, 5 Sept. 81. 029: Near top of outflow. 030: Outflow. 031-033 (=77) The Fountain Spring. 28°21.1’E, 136°17.0’Е. Warrina 431485 (Williams, 1979:14). Coll. WZ, 9 Sept. 81. 031: Top of outflow. 032: Near outflow of top pond. 033: Near bottom of outflow. 034 (=78) Big Perry Springs (West). 28”20.4'S, 136°20.6'E. Warrina 438487 (Williams, 1979:16). Coll. WZ, 9 Sept. 81. Top and middle of outflow. 035-037 (=79) Twelve Mile Spring. 28°18.5'S, 136°15.4'E. Warrina 427490 (Williams, 1979:13). Coll. WZ, 6 Sept. 81. 035: Top of spring. 036: Base of mound. 037: Near top of outflow. 038-040 (=80) Outside Springs (middle one). 28°16'S, 136°12.5'E. Warrina 422496 (Williams, 1979:8). Coll. WZ, 6 Sept. 81. 038: Top of outflow. 039: Middle of outflow. 040: Near bottom of out- flow. 041 (=81) Outside Springs (southern one). 28°17'S, 136°12.7'E. Warrina 422495 (Williams, 1979:8). Coll. WZ, 6 Sept. 81. Middle of outflow. 112 PONDER, HERSHLER & JENKINS 042-044 (=82) Freeling Springs (southernmost). 28°4.3'S, 135%54.4'E. Warrina 390518 (Williams, 1979:27). Coll. WZ, 7 Sept. 81. 042: Top of outflow. 043: Middle of outflow. 044: Near bottom of outflow. 045-046 (=83) Freeling Springs (one crossing track). 28°4.3'$, 135°54.4'Е. Warrina 390518 (Williams, 1979:27). Coll. WZ, 7 Sept. 81. 045: Near top of outflow. 046: Near bottom of outflow. 047 Lodden (=Louden) Spring. 28°35.2'S, 136°24.0'E. Warrina 443456 (Williams, 1979:48). Coll. WZ, Sept.81. Spring dry. 048 Melon Spring. 28”15.3'S, 136°4.9’E. Warrina 408496. Coll. WZ, Sept. 81. General. 049 Levi Spring. 28°22.9'S, 136°09’E. Warrina 416482. Coll. WZ, Sept. 81. General. 050 Spring in creek bed NE of Nilpinna Springs. 28°14'S, 135°43'E. Warrina 367503. Coll. WZ, Sept. 81. General. 051 The Vaughan Spring. 28°17.4'S, 136°10.1’E. Warrina 426493 (Williams, 1979:12). Coll. WZ, Sept. 81. General. 659 Unnamed spring. 27°47.1'S, 135°39.9’E. Oodnadatta 364553 (Williams, 1979:49). Coll. WP and WZ, 1 June 83. General. 660 Okenden Spring and Воге. 27°50.8'S, 135°44.0'E. Oodnadatta 372547 (Williams, 1979: 54). Coll. WP and WZ. 1 June 83. General. 661 Big Cadnaowie Spring. 27°51.5'$, 135°40.1’E. Oodnadatta 364545 (Williams, 1979:53). Coll. WP and WZ. 1 June 83. Outflow and top pool. 662 Little Cadnaowie Spring. 27°47.4'S, 135°56.5'Е. Oodnadatta 367554 (Williams, 1979: 51). Coll. WP and WZ, June 83. General. 663 Freeling Springs, main spring (southernmost). 28°4.3'S, 135°54.4'Е. Warrina 390518 (Williams, 1979:27). Coll. WP and WZ, 2 June 83. Quantita- tive samples taken. 664 Freeling Springs, “Well Spring”. 28°4.1'S, 135°54.3’E. Warrina 389518 (Williams, 1979:27). Coll. WP and WZ, 2 June 83. A1: Pool, mud and weed on bottom. A2: Pool on calcrete near water surface. B: Beginning of outflow. C: ca.50m down outflow. 665 Freeling Springs, near “Well Spring”. 28°4.2'S, 135°54.5'E. Warrina 390518 (Williams, 1979:27). Coll. WP and WZ, 2 June 83. A:Head of spring. B:21m down outflow. C:50m down outflow. 666 Unnamed spring, ca.2.5km N. of Freeling Springs. 28°2.0'S, 135°44.1'E. Warrina 389521 (Williams, 1979:29). Coll. WP and WZ, 3 June 83. General. In Peake Creek bed. 667 Tidiamurkuna waterhole-spring. 28°2.3'S, 135°48.9'E. Warrina 380523. Coll. WP and WZ, 3 June 83. General. 668 Melon and Milne springs. 28°15.3’S, 136°4.9'E. Warrina 408496 (Williams, 1979:7). Coll. WP and WZ, 4 June 83. General. 670 Hawker Springs, 4.1km from N. turnoff on N. side of track. 28°24.4'S, 136°11.0’Е. Warrina 419478 (Williams, 1979:20). Coll. WP and WZ, 4 June 83. A:Head of spring. B: Beginning of outflow. C:Outflow. 671 Hawker Springs, 6.3km from N. turnoff, N.E. of track. 28°25.3'S, 136°11.3'E. Warrina 421484 (Williams, 1979:20). Coll. WP and WZ, 4 June 83. General. 672 Hawker Springs, 7.3km from N. turnoff, W. of track. 28°26.0'S, 136°11.6’E. Warrina 421475 (Williams, 1979:20). Coll. WP and WZ, 4 June 83. A:Head of spring. B:12m down outflow. C:40m down outflow. D:Outflow of subsidiary spring. 673 Hawker Springs. 8.3km S.E. from N. turnoff to springs. 28°26.8'S, 136°11.6'E. Warrina 421474 (Williams, 1979:20). Coll. WP and WZ, 4 June 83. General. 674 Spring Hill Springs, S. side of Spring Hill. 28°25.3'S, 136°9’E. Warrina 416476 (Williams, 1979:23). Coll. WP and WZ, 5 June 83. General. 675 Edith Spring. 28°28.0'S, 136°5.4’E. Warrina 409472 (Williams, 1979:24). Coll. WP and WZ, 5 June 83. General. 676 Talton Springs. 28°31.6'S, 136°5.7'E. Warrina 410463 (Williams, 1979:46). Coll. WP and WZ, 5 June 83, General. 677 Brinkley Springs. 28°30.4'S, 136°16.9’E. War- rina 432466 (Williams, 1979:44). Coll. WP and WZ, 5 June 83. General. 678 Strangways Springs (near Irrapatana), ca.100m S.W. of ruins. 29°9.88'S, 136°33.09’E. Warrina 458386 (Cobb, 1975:68, Williams, 1979: 64). Coll. WP and WZ, 6 June 83. A:Upper outflow. B:Pool on top of mound. 679 Strangways Springs (near Irrapatana), ca.200m S.W. of ruins. 29°9.79'S, 136°33.09’E. Warrina 458386 (Cobb, 1975:68, Williams, 1979: 64). Coll. WP and WZ, 6 June 83. A1:Pool а top of ‚ mound on edges out of water. A2:Pool and upper outflow. A3: Lower outflow. 680 Strangways Springs (near Irrapatana), ca.130m N.W. of ruins. 29°9.98'$, 136°32.87’E. Warrina 458386 (Cobb, 1975:68, Williams, 1979: 64). Coll. WP and WZ, 6 June 83. General. 681 Warburton Spring. 29°16.68'S, 136°40.31’E. Curdimurka 471373 (Cobb, 1975:65). Coll. WP and WZ, 7 June 83. A: Pool at top, А1 on edge, A2 in pool. B:Upper outflow, B1 from edges, B2 from wa- ter. C: Lower outflow. 682 Unnamed spring near Warburton Spring. 29°16.57'S, 136°40.19'E. Curdimurka 472373. Coll. WP and WZ, 7 June 83. General. 683 Jersey Springs. 29°20.81'S, 136°45.37’E. Cur- dimurka 481364. Coll. WP and WZ, 7 June 83. A: Beginning of seepage. B:Outflow. AUSTRALIAN SPRING HYDROBIIDS 113 684 Coward Springs Railway Bore. 29°24.21'S, 136°48.89’E. Curdimurka 357486. Coll. WP and WZ, 7 June 83. Exit from pool and upper outflow. 685 Blanche Cup Spring. 29°27.35'$, 136°51.57'S. Curdimurka 491351 (Cobb, 1975:51). Coll. WP and WZ, 7 June 83. Quantitative samples. Also quanti- tatively sampled 29 Jan. 84. 686 Priscilla Spring. 29°34.30'S, 137°13.52’E. Cur- dimurka 528336 (Cobb, 1975:41). Coll. WP and WZ, 8 June 83. General. 687 Venable Spring/bore. 29°40.78'S, 137°22.03'E. Curdimurka 544323 (Cobb, 1975:28). Coll. WP and WZ. 9 June 83. General. Low mound with bore. 688 Beatrice Spring/bore. 29°37.46'S, 137°21.95’E. Curdimurka 544330 (Cobb, 1975:25). Coll. WP and WZ, 9 June 83. Bore and large mound with seepages. 689 Dead Boy Spring. 29°36.08'S, 137°24.44’E. Curdimurka 547333. Coll. WP and WZ, 9 June 83. General. Very small spring in large abiotic spring (HDB005). 690А Finniss Swamp West. 29°35.68’S, 137°24.66’E. Curdimurka 549333 (Cobb, 1975:19). Coll. WP and WZ, by helic., 9 June 83. Small spring—general (HWF039). 6908 Finniss Swamp West. 29°35.68’S, 137°24.66’E. Curdimurka 549333 (Cobb, 1975:19). Coll. WP and WZ, by helic., 9 June 83. Small spring—general (HWFOA2). 690C Finniss Swamp West. 29°35.68'S, 137°24.66’E. Curdimurka 549333 (Cobb, 1975:19). Coll. WP and WZ, by helic., 9 June 83. Small spring—general (HWFO41). 691А Finniss Swamp West. 29°35.68’S, 137°24.66'E. Curdimurka 549333 (Cobb, 1975:19). Coll. WP and WZ, by helic., 9 June 83. A:Head of spring in swampy, shallow pool. B:Upper outflow. C:Upper part of middle outflow. D:Lower outflow (HWF031). 692A Bopeechee (or Zeke) Springs. 29°36.49'S, 137°23.15'E. Curdimurka 547332 (Cobb, 1975:21). Coll. WP and WZ, 9 June 83. Very small mound and seepage, ca.40m S.S.W. of 692B (HBO003). 692B Bopeechee (ог Zeke) Springs. 29°36.49'S, 137°23.15’E. Curdimurka 547332 (Cobb, 1975:21). Coll. WP and WZ, 9 June 83. General (HBO002). 693 Old Finniss Springs. 29°34.97'S, 137°26.79’E. Curdimurka 553336. Coll. WP and WZ, by helic., 12 June 83. Quantitative samples. Also sampled in Aug.1983 (non-quantitative) and Jan.1984 (quanti- tative) (HHOFO092). 694 Old Finniss Springs. 29°34.97'S, 137°26.79'E. Curdimurka 553336. Coll. WP and WZ, by helic., 10 June 83. General. A: Spring 13x 24m (HOF089). B:Spring 15 x 37m (HOF088). C:Spring 8x 17m (HOF087). Three small springs grouped together. 695 Smith Springs. 29°30.37'S, 137°21.42'E. Cur- dimurka 544344 (Cobb, 1975:31). Coll. WP and WZ, by helic., 11 June 83. General examination of all springs. 696 Gosse Springs. 29°28.0'S, 137°20.6’E. Curdi- murka 542349 (Cobb, 1975:34). Coll. WP and WZ, by helic., 11 June 83. General (3 separate springs examined). Main spring also examined 29 Jan. 84. 697 McLachlan Springs. 29°27.8'S, 137°19.0’E. Curdimurka 539349 (Cobb, 1975:37). Coll. WP and WZ, by helic., 11 June 83. General (a large sand mound). 698-9 Unnamed springs near McLachlan Springs. 29°28'S, 137°19.1'E. Curdimurka 540348. Coll. WP and WZ, by helic., 11 June 83. General. 700 Unnamed spring 1.5km S.E. of McLachlan Springs. 29°28'$, 137°19.1’E. Curdimurka 540348. Coll. WP and WZ, by helic., 11 June 83. General— several small seeps. 701 Unnamed spring in W. Lake Eyre South. 29°19.9'S, 137°10.9’E. Curdimurka 526366. Coll. WP and WZ, by helic., 11 June 83. General. 702 Unnamed spring in S. end of Lake Eyre South. 29°21.60'S, 137°16.54’E. Curdimurka 535363. Coll. WP and WZ., by helic., 11 June 83. General. 703 Emerald Spring. 29°23.14'S, 137°3.70'E. Cur- dimurka 513359 (Cobb, 1975:45, Williams, 1979: 61). Coll. WP and WZ, by helic., 11 June 83. A: Upper outflow. B:Middle outflow. 704 Fred Springs West. 29°31.08’S, 137°16.85’E. Curdimurka 536344 (Cobb, 1975:38). Coll. WP and WZ, by helic., 11 June 83. General. Very little sur- face water. Fred Springs East was also visited but no station number was allocated. 710 Old Finniss Springs (nearest ruin). 29°35.08’S, 137°27.0'E. Curdimurka 553336. Coll. WP and WZ, by helic., 12 June 83. General (one of several sim- ilar mounds examined) (HOF081). 711A Hermit Hill Springs. 29°34.32'S, 137°25.56’E. Curdimurka 551336 (Cobb, 1975:16). Coll. WP and WZ, by helic., 12 June 83. General (HHS172). Sev- eral similar mounds examined (B-V). 711W Hermit Hill Springs. 29°34.24'S, 137°25.86’E. Curdimurka 552336 (Cobb, 1975:16). Coll. WP and WZ, by helic., 12 June 83. General (HHS149). Firmer sediment in outflow than 711A. 712 Hermit Hill Springs (E.group). 29°34.24'S, 137°25.86’E. Curdimurka 552336 (Cobb, 1975:16). Coll. WP and WZ, by helic., 12 June 83. General (HHS064—077). Group of 3 small springs with com- mon outflow. 714 Cardajalburrana Spring. 28.112125, 135°33.1'E. Warrina 352505 (Williams, 1979:31). Coll. WP and WZ, by helic., 13 June 83. General. 715 Weedina Springs. 28°23.6'S, 135°38.6’E. War- rina 362480 (Williams, 1979:37). Coll. WP and WZ, 13 June, 83. General. 114 PONDER, HERSHLER & JENKINS 716 Eurilyana Spring, on S. side of Lake Cadibar- rawirra. 28°55.5'S, 135°26.9’E. Warrina 341416 (Williams, 1979:43). Coll. WP and WZ, 13 June, 83. General. 717 Loyd Bore, Francis Swamp. 29°7.3’S, 136°17.7'E. Warrina 432393 (Cobb, 1975:1, Williams, 1979:58). Coll. WP and WZ, 13 June, 83. A:At point of outlet. B:General swamp around main outlet. C:In outflow draining out of тат part of spring. 718 Anna Springs East (?bore). 29°31.90'S, 136°59.32'E. Curdimurka 506345. Coll. WP and WZ, by helic., 13 June 83. General. 719 North West Springs. 29°33.51’S, 137°24.11’E. Curdimurka 548337. Coll. WP and WZ, by helic., 13 June 83. General. A-C:3 small springs in S.E. of group (HNW005,007,010). 719D North West Springs. 29°33.51'S, 137°24.11'E. Curdimurka 548337. Coll. WP and WZ, by helic., 13 June 83. General. Small spring in N. of group (HNWOO3). 720 Francis Swamp, one of springs in middle part of swamp. 29°8.6’S, 136°17.3’E. Billa Kalina 433 388 (Cobb, 1975:1). Coll. WP and WZ, by helic., 14 June 83. A:In middle of spring outlet area. B:In swamp surrounding outlet. C:In outflow. 721 Francis Swamp, springs near south end. 29°10'S, 136°19.2’E. Billa Kalina 434386 (Cobb, 1975:1). Coll. WP and WZ, by helic., 14 June 83. Three springs samples (A-C). 722 Margaret Spring. 29°13.2’S, 136°20.8’E. Billa Kalina 436739. Coll. WP and WZ, 14 June 83. Gen- eral. 723 Fenced Spring (Billa Kalina). 29°29.1'S, 136°26.9’E. Billa Kalina 447347. Coll. WP and WZ, by helic., 14 June 83. A:Pool at top. Mostly open water. B:Upper outflow. C:Middle outflow. D:Edge of outflow. 730 Finniss Swamp West, near main road. 29°35.92'S, 137°24.57'E. Curdimurka 548333. Coll. RH and EH, 27 Aug. 83. General collection (HWFO48). 731 Old Woman Springs. 29°35.41'$, 137°27.35’E. Curdimurka 554334. Coll. WP and BJ, 30 Aug. 83. General (HOWO24). Small spring reactivated after seismic work in area. 732A Old Woman Springs. 29°35.46’S, 137°27.35'Е. Curdimurka 554334. Coll. WP and BJ, 30 Aug. 83. General-small mound near 732B (HOWO15). 732B Old Woman Springs. 29°35.46’S, 137°27.35'Е. Curdimurka 554334. Coll. WP and BJ, 30 Aug. 83. General (HOWO13). 733 Old Woman Springs, main spring. 29°35.57’S, 137°27.28'E. Curdimurka 554334. Coll. WP and BJ, 30 Aug. 83. A:Top pool. B:Beginning of outflow. C:Upper part of outflow. D:Lower outflow. E:Seep- age at head of pool (HOWO009). 734 Old Finniss Mound Spring. 29°35.00’S, 137°28.18'E. Curdimurka 556335. Coll. WP and BJ, 30 Aug. 83. General (HOF094). 735 Sulphuric Springs. 29°36.51'S, 137°24.20’E. Curdimurka 548333. Coll. WP and BJ, 30 Aug. 83. General (HSS016). 736 Sulphuric Springs. 29°36.68'S, 137°24.20’E. Curdimurka 558332. Coll. WP and BJ, 30 Aug. 83. General (HSS014). 737 Sulphuric Springs. 29°36.61’S, 137°24.01’E. Curdimurka 547332. Coll. WP and BJ, 30 Aug. 83. General (HSS006). 738 Jacobs Spring. 29°29.38’S, 137°8.95’E. Curdi- murka 523347 (Cobb, 1975:44). Coll. WP, RH and DB, 31 Aug. 83. General. 739 Blanche Cup Spring. 29°27.35'$, 136°51.57’E. Curdimurka 491351 (Cobb, 1975:51). Coll. WP, RH and DB, 31 Aug. 83. Transect of pool. 740 Kewson Hill Springs. 29°22.31'S, 136°47.13’E. Curdimurka 484362. Coll. WP, RH and DB, 31 Aug. 83. General. On side of very large mound. 741 Kewson Hill Springs. 29°22.28'$, 136°47.16’E. Curdimurka 484362. Coll. WP, RH and DB, 31 Aug. 83. Upper 10m of outflow. 742 Kewson Hill Springs. 29°22.23'$, 136°47.16’E. Curdimurka 484362. Coll. WP, RH and DB, 31 Aug. 83. A:Upper outflow. B:Lower outflow. 742В Kewson Hill Springs. 29°22.23'S, 136°47.16’E. Curdimurka 484362. Coll. WP, RH and DB, 31 Aug. 83. Lower outflow. 743 Coward Springs Railway Bore. 29°24.21'S, 136°48.89'E. Curdimurka 357486. Coll. WP, RH and DB, 31 Aug. 83. Beginning of outflow. A:Pool at bore on edge. B:On surface of damp mud near large clump of bullrushes. C:In water near large clump of bullrushes. 744 Little Bubbler Spring. 29°27.35'S, 136°51.91’E. Curdimurka 492351 (Cobb, 1975:51). Coll. WP, BJ and CW, 1 Sept. 83. A:Beginning of outflow. B:34m down outflow. C:Lower outflow. 745 Strangways Spring E. of Bubbler group. 29°29.06'S, 136°53.64'E. Curdimurka 495357. Coll. WP, BJ and CW, 1 Sept. 83. A:Upper outflow. B:Middle outflow. 746 Horse Springs West. 29°29.50’S, 136°54.80’E. Curdimurka 497347 (Cobb, 1975:48). Coll. WP, BJ and CW, 1 Sept. 83. A:General—mostly upper out- flow. B:In solution hole on side of mound. 747 Horse Springs East. 29°29.50'S, 136°55.25’E. Curdimurka 498347 (Cobb, 1975:48). Coll. WP, BJ and CW, 1 Sept. 83. A:Top pool, mostly under stones. B:Outflow. 748 Horse Springs East. 29°29.58'S, 136°55.25’E. Curdimurka 498347 (Cobb, 1975:48). Coll. WP, BJ and CW, 1 Sept. 83. A:Crater-like pool at top. B: Outflow. C:Outflow at base of mound. AUSTRALIAN SPRING HYDROBIIDS 115 749 Spring at Mt. Hamilton ruins. 29°29.71'S, 136°53.95’E. Curdimurka 496346. Coll. WP, BJ and CW, 1 Sept. 83. Pool at top. 750 Anna Springs West. 29°32.04'S, 136°59.26’E. Curdimurka 506345. Coll. WP, BJ and CW, 1 Sept. 83. Pool. 751 Anna Spring/bore East. 29°31.90’S, 136°59.32’E. Curdimurka 506345 (Cobb, 1975:47). Coll. WP, BJ and CW, 1 Sept. 83. General. 752 Main bore/spring, Davenport Springs. 29°40.09'S, 137°35.31’E. Curdimurka 567325 (Cobb, 1975:11-1). Coll. WP, RH and DW, 2 Sept. 83. A:15m down outflow. B:25m down outflow. C: 60m down outflow. 753 Davenport Springs. 29°40.09’S, 137°35.56’E. Curdimurka 567325 (Cobb, 1975:11-1). Coll. WP, RH and DW, 2 Sept. 83. A:Head and uppermost outflow. B:Lower outflow. 754 Welcome Springs. 29°40.09’S, 137°49.44’E. Curdimurka 594324 (Cobb, 1975:1-3). Coll. WP, RH and DW, 2 Sept. 83. A:Uppermost outflow. B: 20m down outflow. C:Pool 25m down outflow. D: 80m down outflow. 755 Welcome Springs. 29°40.42’S, 137°49.75’E. Curdimurka 594323 (Cobb, 1975:1-3). Coll. WP, RH and DW, 2 Sept. 83. A:Head of spring. B:20m down outflow. C:50m down outflow. D:12m down outflow. 756 Welcome Springs. 29°40.77'S, 137"49.75'E. Curdimurka 594323 (Cobb, 1975:1-3). Coll. WP, RH and DW, 2 Sept. 83. A:Pool 4m from beginning. B:Upper outflow. C:Lower outflow. 757 Wangianna Spring/well/bore. 29°40.55’S, 137°42.65'E. Curdimurka 581323 (Cobb, 1975:8). Coll. WP, RH and DW, 2 Sept. 83. General. 758 Welcome Bore/spring. 29°21.02'S, 136°37.38’E. Curdimurka 465364. Coll. WP, RH and DB, 3 Sept. 83. General. 759 Spring at Old Billa Kalina гит. 29°27.66'S, 136°29.75’E. Billa Kalina 453350. Coll. WP, АН and DB, 3 Sept. 83. A:Pool at top. B:Upper outflow. C:Lower outflow. 760 Spring near Old Billa Kalina ruin. 29°27.66'S, 136°29.75’E. Billa Kalina 453350. Coll. WP, RH and DB, 3 Sept. 83. A:Pool at top. B:Upper outflow. 761 Billa Kalina, 1.8km S. of ruins. 29°27.98'S, 136°28.40’E. Billa Kalina 451349. Coll. WP, RH and DB, 3 Sept. 83. A:Seep at head. B:Pool at top. C:Outflow. 762 Billa Kalina Springs. 29”27.98'S, 136°28.40'E. Billa Kalina 451349. Coll. WP, RH, DB, 3 Sept. 83. A:Pool at top. B:Upper outflow. 763 Billa Kalina Springs. 29°28.53’S, 136°27.22'E. Billa Kalina 848348. Coll. WP, RH and DB, 3 Sept. 83. A:Upper outflow. B:Lower outflow. 764 Coward Springs. 29°24.78'S, 136°47.28’E. Curdimurka 484357 (Cobb, 1975:56). Coll. WP, RH and DW, 5 Sept. 83. A:Small seepage on top of mound. B:Beginning of outflow. C:Outflow at base of mound. 765 Spring near W. side of Kewson Hill. 29°22.17'S, 136°46.79'E. Curdimurka 483362. Coll. WP, RH and DW, 5 Sept. 83. General. 766 Е. side of Elizabeth Springs mound. 29°21.36'$, 136°46.30'E. Curdimurka 482363 (Cobb,1975:59).Coll. WP, ВН and DW, 5 Sept. 83. A:Head of spring. B:Outflow from top seep. C:Sec- ond spring on outflow. D:Outflow, terrace area. E: Outflow, lower end of terraces. F:On steep side of hill in outflow. G:Base of outflow. 767 Elizabeth Spring/bore. 29°21.30'S, 136°47.04'E. Curdimurka 483363 (Cobb, 1975:63). Coll. WP, RH and DW, 5 Sept. 83. A:Upper outflow, under wood. B:Outflow on sedge. C:Outflow under wood. 768 Jersey Springs. 29°20.81’S, 136°45.52'E. Cur- dimurka 671753. Coll. WP, RH and DW, 5 Sept. 83. A:Beginning of outflow. B:End of outflow. 769 Jersey Springs. 29°20.81'S, 136°45.52'E. Cur- dimurka 481365. Coll. WP, RH and DW, 5 Sept. 83. A:Head of spring. B:Outflow. 770 Jersey Springs. 29°20.81'S, 136°45.37’E. Cur- dimurka 481364. Coll. WP, RH and DW, 5 Sept. 83. A:Top of seepage. B:Outflow. C:Small seep. 771 Elizabeth‘ Springs, N.W. side of hill. 29°21.30'S, 136°21.14’E. Curdimurka 483364 (Cobb, 1975:59). Coll. WP, RH and DB, 7 Sept. 83. A:Head of spring. B:Upper outflow. C:Lower out- flow. 772 Julie Springs, S.E. side of hill, between Kew- son and Elizabeth springs. 29°21.75'S, 136°46.67’E. Curdimurka 483363 (Cobb, 1975:63). Coll. WP, RH and DB, 7 Sept. 83. A:Pool at head. B:Upper outflow. C:On steep fall, upper outflow. D:Bottom of hill, lower outflow. 773 Julie Springs, S.W. side of hill, between Eliza- beth and Kewson hills. 29°21.68'S, 136°45.06’W. Curdimurka 483363 (Cobb, 1975:63). Coll. WP, RH and DB, 7 Sept. 83. A:Upper pool. B:Upper outflow. C:Lower outflow. 785 Seepages in mound S.W. of Little Bubbler Spring, Blanche Cup Group. 29°27.36’S, 136°51.91’E. Curdimurka 491351. Coll. WP and WZ, 27 Nov. 83. A and В in two very small seeps on mound. 786 Spring N.W. of Little Bubbler Spring, and N.E. of Blanche Cup. 29°27.34'S, 136°51.56’E. Curdi- murka 491351. Coll. WP and WZ, 27 Nov. 83. A:In outlet of spring. B:In upper part of outflow. Сп smaller outflow on same mound. 787 Spring N.N.E. of Blanche Cup. 29°27.35'S, 136°51.57’E. Curdimurka 491351. Coll. WP and WZ, 27 Nov. 83. 1000 Strangways Springs, near Irrapatana, large spring on southern end of hill. 29°10’S, 136°33’E. Curdimurka 458386. Coll. WP and DW, 31 May 85. A:Pool at head. B:Beginning of outflow. C:Lower outflow. 116 PONDER, HERSHLER & JENKINS 1001 Big Perry Spring. 28”20.45'S, 136°20.7'E. Warrina 438487. Coll. WP and DW, 31 May 85. A:Beginning of outflow. B:Middle part of outflow. C-D:Small seeps on same mound. 1002 The Fountain Spring. 28°21.1S, 136°17’E. Warrina 431485. Coll. WP and DW, 31 May 85. A:Pool at head. B:Beginning of outflow. C:Middle part of outflow. D:Lower outflow. 1003 Twelve Mile Spring. 28°18.5'S, 136°15.4’E. Warrina 427490. Coll. WP and DW, 1 June 85. A, B:Seeps on same mound as main spring. C:Upper outflow, main spring. D:Middle outflow, main spring. 1004 The Vaughan Spring. 28°17.4'S, 136°10.1’E. Warrina 426493. Coll. WP and DW, 1 June 85. General. 1005 Outside Springs (most southern and eastern). 28°17.39'S, 136°12.69'E. Warrina 422495. Coll. WP and DW, 1 June 85. General. 1006 Outside Springs (middle one of group). 28°16'S, 136°12.5’E. Warrina 422496. Coll. WP and DW, 1 June 85. A:Upper outflow. B:Middle out- flow. 1007-8 Nilpinna Springs (at homestead). 28°13'$, 135°42'Е. Warrina 366502 (Williams, 1979:35). Coll. WP and DW, 16 June 85. General. Several additional nominal springs were visited which proved to be dry and no station numbers were allocated. These included: Oodnadatta Sheet: Unnamed. 365552 (Williams, 1979:50). Peake and Denison Geological Map 1:150,000. Oodloodlana and Oortooklana Springs. To the West of Mt. Denison. Sand Creek, Blind, Coppertop and Mud Springs. To the East of Mt. Denison. Warrina Sheet Kerlatroaboorntallina Springs (Mt. Kingston Bore). 388527 (Williams, 1979:26). List of springs not sampled There are several springs that, for various rea- sons, have not been sampled. They are grouped in the list below according to the 250,000 map sheet on which they are found. Springs that are found in spring groups that have been subsampled are not included in this list. Some of these have been re- cently visited by consultants from Social and Envi- ronmental Assessment (SEA) while preparing a re- port for the South Austrailian Govt. on the mound springs. Oodnadatta: Unnamed spring near Big Cadnaowie Spring (=Cadna-owie Springs or MacEllister Springs). 365546. Williams (1979:52) lists this spring but did not visit it. Visited by SEA, no snails reported. Mt. Toondina Spring. 330534. Listed by Williams (1979: 56) but not visited by him. Warrina: Primrose Spring. 441509. Small spring and seeps; described by Williams (1979:5). Fanny Springs. 425488. Small seeps and ponds; described by Williams (1979:10). Little Perry Spring. 440494. Bore on spring, flow very small (Williams, 1979:15). Several springs West of Lat.135.40'S. on the War- rina Sheet have not been visited. The few springs sampled in this area did not contain any inverte- brates and were mostly just saline pools. Some ex- amined only from the air appeared to be very sim- ilar to those sampled. Oolgelima Spring was visited by SEA, no snails were reported. Billa Kalina: William spring. 442405. Listed by Williams (1979: 58), but was not visited by him. Visited by SEA, no snails reported. Emily Spring. 443401. Listed by Cobb (1975:3) but not visited by him. Curdimurka: Walcarina Spring. 508346. Cobb (1975:46) lists this “spring” and states that it is a small seepage. At- tempts to locate this spring from the air have failed. Stations at which no hydrobiids were collected During the course of the survey of mound springs a large number of springs within spring groups were examined that, mainly because of time constraints, were not allocated station numbers. Some of these springs were rejected because they lacked inverte- brates. Thus, with the exception of a few stations in the Hermit Hill area, the following list of springs that were found not to contain hydrobiids applies only to isolated springs or whole spring groups. Oodnadatta Springs: Okenden (660), Little Cadnaowie (662), unnamed (659). Northern Springs: Melon and Milne (048, 668), Levi (049), The Vaughan (051), Edith (675), Talton (676), Brinkley (677). North Western Springs: Tidiamurkuna (667), Nilpinna (050, 1007-8), Carda- _ jalburrana (714), Weedina (715), Eurilyana (716). Middle Springs: Anna (718, 750, 751). Southern Springs: Jacobs (738), unnamed in Lake Eyre South (701), McLachlans (697, 698-700), Gosses (696), Fred (704), Smith (695), Beatrice (688), North West (719), Wangianna (757), Hermit Hill area: Old Woman Group (731, 732), Old Finniss Group (734). Springs to the East of Marree: (Numbers refer to grid references on the 1:250,000 sheets) Marree Sheet: Hergott Spring (now a Боге) (620328), Wirringina Springs (650314), Rocky (233343) and Reedy Springs (233341). Note: Most of the extant springs to the East of Marree have been sampled. W. Zeidler has visited Lignum Dam and Spring and Four Mile Spring and Bore and in both no evidence of the original spring AUSTRALIAN SPRING HYDROBIIDS 117 remains. In our experience, and from the informa- tion provided by Cobb (1975) regarding these springs they are all either heavily degraded by bores being placed on the springs or they are re- duced to very small seeps. The one exception is Reedy Springs. Callabonna Sheet: Public House Spring (not named on map) (241314) and Petermorra Springs (246313). Note: Springs in the Northern Flinders Ranges and east and northeast of the Northern Flinders Ranges are not listed here, although many have been sampled. None contain the invertebrate fauna seen in the Lake Eyre Subgroup. Locality maps The locations of the informal spring sys- tems are given in Fig. 2, the more detailed locality maps in Figs. 58-63 and the key to the locations of the locality maps in Fig. 57. The distributions of the taxa are shown in Figs. 13, 26, 31 and 39 in the taxonomic sec- tion. In each map the main drainage channels and the main points of reference are shown. Lake Eyre is a salt lake that contains water only after flooding, filling only once in several years (Kotwicki, 1986). The general topogra- phy is flat. LAKE EYRE, (NORTH) D LÄKE EYRE (SOUTH) Hamilton > Hill FIG. 57. General location map. Numbered rectangles refer to Figs. 58-63. On each of the following maps only sampled springs are indicated. 118 PONDER, HERSHLER & JENKINS - Freeling Springs = | 4 4 | Warinna О ia 5 $ : NAS LT Gate WH. À AT ‘ = В $ Y \ \ “==-=2 ZEN 5 Nilpinna Spring 7 N \ © © ! il >= = 1! Y Les ре o Z x Y И \ === Ne © ME > G > Г 5 2 | \ FT À ) ‘ lies es 34 So pe 20015 um AI | ENT “m = 1” и а = \ A И’ 45 3 /! + à LA \ 4 x \ ‘Sy Y \Edwards Creek © == Crossland Hill A [| A y N I N} Ÿ Gi 2 y Is is - = AN 1 . Weedina Spring Tea IN Edadurrana Spring L Lake `` Warrangarrana \ \ ` \ 1 y Warrangarrana Spring И | ' ' / =>) ' ' À 135°30' LONG © 1® 118. 113 1 ® \ ıWeedina WH . Cadaree Hill К => } | Meyanungada Hill 2 | . \ z | ZEN nee ne AR AS Mungyamarrilyna = \ \ pr \\ Swamp \ nn N \ \ 1? \ il у \ \ (| FIG. 58. The North Western Springs and Freeling Springs. AUSTRALIAN SPRING HYDROBIIDS 119 Coppertop Hill Mt. Denison 136°00' LONG. 136° /5'LONG. Far NIT AS < pa ; saine Spring, Bore, - 24875 LAT. Melon Spring 7 р er + Outside Springs The Vaughan Spring x e Os Twelve Mile Spring ” Fanny Springs „-— os Ee 4 pie AAA iG y > 7 < ( Y, SEA mi Charles NS, = RITTER NEN \ м Big Perry Springs he Роитат Spring 7 * Levi Spring Е + A vi у 670, _ / pring Hill Spring Hill Spring * | IS E) 25 Hawker Е 672 Springs o < o ~ = À Me ee © a LONG = 136915 Mt Margaret Mt. Fox DE / N 28°30'LA. 28°30'LAT. — 7, = Brinkley Springs Loudon Spring 22 - White Hill ner - ANS u . Mt. Anna Scale 1:250 000 5 Окт mm FIG. 59. The Northern Springs. 120 PONDER, HERSHLER & JENKINS u 4 — 136° 15' LONG Lake William Y. AN Le 7 NEC ee = 3 Sk Cr УХ lee = AA иг & a SS en LA | CEA, a = = SZ Strangways г N ee NS = и Ww \ ~ Bis 29 15' LAT Г ' 29%/5' LAT. S a / ) ES À a 2 К ( ne \ ) y 4 => Beresford Spring” S PAS Berestord Hill E e Warburton Spring. o — ? Er ве) ge ER as \ en Teepena Bluff Spring at Old En Billa Kalina Ruins x. / 762 1701 к Welcome Bore * 7632” S ta ( oS Fenced SA J = MA 8 О > 7, Y 29° 30' LAT. 2 $ —- 28050 LAT. Le £ 1 Scele | 250000 5 a AT + 136° 15 ' LONG . New Peter Hill ‘ Peter Hill FIG. 60. The South Western Springs and the Beresford Spring Complex. Beresford. Beresford Spring’ Beresford Hilf” Warburton $; prings © So RES ve \ №2 --~~ Paisley Pond EN = Base) Ca à Hamilton AUSTRALIAN SPRING HYDROBIIDS — /36°45 LONG sr LAT N Bruce WH"===. \ = Wi aS Jersey Springs N AS N & ~ EN L Y Anchor Rise. / AE sy 71 767 + Elizabeth Springs \ — Julie Springs 7 M С Kewson Hill Springs LTR AROS > > DS oward Springs Coward Springs > Railway Bore == y > = E re Bubbler =—_—”, AR Little Bubbler Spring "N, Hamilton Hill‘ Blanche Cup Spring ` | АХ NEN "р, \Strangways \ ~ = Е t. Hamılton Spring , ( EN N Sa E Horse Springs East ‘\\Worse Springs West | A Sa 7 = à №-= New Twin Hill 2045’ { 3 1] u A Tent Hill А Twin Hill FIG. 61. The Middle Springs and Emerald Springs. > ÈS SAS A Anna Springs 121 `^ Curdimurka Lo) a oe, L] ух AE lo E Y 122 PONDER, HERSHLER & JENKINS Jacobs Spring = \ Coo, Priscilla / Lake Phibbs_) 7 \ 7 Priscilla Springs o _ y Rowe Swamp 1:250000 5 Scele McLachlan Springs Fred Springs ыы North West Springs СГ Bopeechee \ у Beatrice * Spring [- PD e \| ® © © a + Na XB, + = Venable Springs Y N ÓN к , - . Eyre Lookout ) - Hermit Hill ) West 4 Finniss ie, Springs FIG. 62. The western Southern Springs. e F e CAS avenport Springs Cadnia Hill o Finniss Springs" = uses‘ AUSTRALIAN SPRING HYDROBIIDS 123 Little Cadnaowre — Spring <“. Algebuckina Hill * 135° 45' LONG. r 28° 00'LAT. Peaked Rise N m. 4 Scale | 250000 5 29° 30' WX . Mt. Alford ~ => Callanna = Attraction Hill . LR ^^ MARREE 4 IN N Welcome Springs Glen Hill Dome Hill FIG. 63B. The easternmost Southern Springs. 124 PONDER, HERSHLER & JENKINS APPENDIX 2 TABLES OF MEASUREMENTS The following tables are a summary of the measurement data used in the statistical ana- |узез. The original data set was analysed at the population level but the volume of these data is far too large for publication and, con- sequently, the data are presented only at the species level and for those infraspecific taxa recognised here as “forms”. Copies of the full data set are housed in the Australian Museum and may be made available on request to the Senior author. The means (top figure) and standard devi- ation (bottom figure) are given for each char- acter for each species or form. The number of individuals measured is given in parenthesis in the first column, which also indicates the sex (F=female, M= male). Where the number of individuals measured for any one character is less than the number in the first column, this is indicated in parenthesis between the mean and SD. An explanation ofthe character codes and details concerning methods of measuring are given in the methods section. 125 AUSTRALIAN SPRING HYDROBIIDS (panunuoo) esse eee 6ly lt 9010 LGO'O 26510 SSOO 8€£c 0 0$0`0 6200 02,0 81<`0 ЕГО GtL'O LOC'O 98£ 0 $ (pal) (ERDE Et) (ELL) (РОН) (29) (29) GS'z 0Z'0 OL'O 671 65'0 eze 091 810 602 90'£ 021 981 le 2 67 x 3 (292 ‘p9Z ‘191 ‘eZ ‘BEL ‘E89 ‘629 ‘650 ‘EEO ‘900 SUONEIS) Y WO} eonenbe y 98/0 €b00 6200 S900 2200 EbLO StOO ESOO. SYL'0 СО 9/00 57800 Sito 690 $ (St) (LL) (11) (11) (11) (€) (5) 5/5 62°0 610 91 sro 60€ sr 1 810 691 gr 2 evi! eS'L 46 BEE. RX W 9080 0S00 0200 19700 1600 5710 7900 2200 1500 9600 6700 S600 2600 0850 $ (02) (91) (91) (91) (91) (91) (2) (2) ES Gz'0 10 921 77'0 60'€ Ут 610 LEN бус | LS} 46 L OI 3X 4 (E02 uonels) 9 0} eyd890e y 2001 2Zr00 6200 2800 8E00 5910 85900 2500 сего LOS D 600 со 510 6520 3199 (931) (921) (931) (921) (052) (805) (232) (992) (992) 6b'€ 930 GL'O 021 97'0 Loe ВТ зо gol вес 621 Lek 6/1 162 xX и ЕЕ НЕЕ ЕВЕ ЕЕ ЗЕЕ E НЕ Et o RA E A PAGA ate ee e 6660 9700 6200 2/00 8€0°0 ЕКО 170`0 £€0'0 14280) 180 00!'0 SILO cel'0 vsc'0 $ (8s!) (sel) (Set) (Ser) (set) (ler) (251) (eer) (eer) (set) Ise 920 SO 12 970 70`Е os! 61'0 99 1 63z 05`1 cel El poe x 4 (GEL ‘EEL ‘LZ ‘114 ‘0769 ‘9769 ‘VY69 ‘69 ‘269 ‘169 ‘069 ‘689 SUONEIS) 9 шло} BIdeooe y Lott vS0;0 2200 600 zr00 L220 — 7500 5600 580`0 60 7/00 ¿600 9910 92го $ (95) (05) (OS) (09) (0S) (05) (0S) (9p) (9p) 7/5 GO — 1410 051 8r'0 ee OS'L LL'O Da Sz evil evil 961 055 x W 2060 €S00 LEO0 9600 8200 ELZO 1100 9500 9600 9SL'0 1200 500 920 050 53 (65) (15) (15) (15) (15) (55) (55) (92) (92) VA ZO 05° 87'0 Sle OS'E 810 08'1 1972 ri op"! 202 Ore x (992 ‘ESZ ‘E00 ‘ZOO SUONEIS) y шло} BIdesse y Nd 9d Hd 10 Gd ML Md AOD gm ма МУ НУ MS HS ‘ON pue xas AA AO A A A De Be Sr E AN RE A ‘HOUM ÁPOQ JO JOYUM-Jey 3$} JO YIPIM “gm SHOUM цэцоэоз|з} jo Jaquinu ‘ML ‘UIPIM 194$ ‘MS зубец jjeys ‘HS “sjioym youo9ojoid jo Jaquinu ‘Ма ‘shed Jejnosado jo лэашпи ‘Ма ¿Bad Jejnosado }5э1е} jo jybiay ‘На ‘youo9sojoid JO Jyaweip шпцихеш ‘Gd ‘Wnnaedo uo леэшз snosJeojes jo fuel ‘24 ‘шпполэдо jo y¡Bua ‘10 ‘зоцм ajeunnuad jo Aıxanuoo ‘AD ‘роцм Apog jo yyBua] ‘Mg :upim alnuade ‘му зубец almuade ‘Ну ‘s}juawainseaw Jejnojado pue ¡pays 'eonenbe ‘+ pue ejdesoe вэ/цр0э5ио- ‘W8l 3719WL PONDER, HERSHLER & JENKINS 126 19/0 +900 650`0 0800 1500 2220 9500 9200 6900 0810 80,0 +9L'0 6+L'0 093'0 $ (62) (Sz) (Sz) (Sz) (Sz) (ЕН (81) (ЕН (9) (<) 00'€ L£ 0 sro 61 25'0 0€'€ 6b'1 L2'0 90 2 plz LOL 6/1 ze 865 xX N 1080 6800 8£00 +900 8200 SOZO 90L0 9100 5010 OPrL'o zero 621.0 ZLL‘O ezz'0 $ (52) (Le) (12) (12) (12) (8) (el) (8) (S) (g) Sle 6£ 0 ЕО rac 75'0 eee pS"! ez'0 £le Sez LOL 281 ze’ УР x 4 = (699 ‘970 Suone]S) g WO} eoyenbe “y ZOLL 9G00 1200 +800 8r00 9950 6100 9200 LLO 930 60L'0 0SL'0 86L'0 Ler’ $ (Se) (22) (22) (22) (22) (82) (62) (82) (Sz) (Sz) 20'E S0'0 r0'0 col LS'O 66 2 OS'E 210 6/1 cg2 Lv! 691 Loz BE x N 1960 1500 5500 ZELO 2900 EIEO 7500 2200 ZbLO0 9220 660'0 ¿SyO 590 Str oO $ (ve) (62) (62) (62) (62) (Ga) (82) (Ga) (La) (12) ve 90'0 70'0 9€'1 69'0 Z0'€ 6v'1 AO) 161 Lo? ZS‘ ZA Ale 785 x 4 (192 'LbvZ ‘E89 SUOIEJS) y WHO} ‘jo eonenbe y [ГЕ 8900 Zb00 9800 600 8bL0 100 2500 SILO ZELO LLL'O 60L'0 2910 192`0 5 (68) (v8) (v8) (v8) (v8) (22) (28) (SZ) (Zr) (Lr) 20'5 Gz'0 го pS'L 75`0 97€ 6v'1 80 902 20'5 РА 981 ge 2 РЕФ x и 002 1 +900 8500 6/00 2S00 9510 5900 050`0 Уго 65910 SOLO ELLO 8SL'0 GGz'0 (06) (Sg) (68) (68) (Sg) (28) (Sg) (62) (9p) (9$) 582 520 ero 851 sg0 05'5 ем 610 28 she $171 061 Gta ger x 3 (Р9/ ‘ZpZ ‘BEL ‘629 ‘650 ‘EEO ‘900 SUONEIS : 140} jesıdAy) y wo, eonenbe Y ¿eE Ll SOLO 19500 velO 1900 0520 2700 0500 0610 6520 GGL'0 0/10 [у2`0 zero $ (pal) (pit) (HE) (pet) (ptt) (ook) 0941) (01 (22) (22) vvz 02:0 010 251 €S'0 07'€ 6v'1L 170 161 162 rg 1 811 822 G6 € x W a AUSTRALIAN SPRING HYDROBIIDS 127 TABLE 18B. Fonscochlea accepta and F. aquatica, pallial measurements. AC, distance of gill apex from left side of filament; CO, distance between posterior end of ctenidium and posterior end of osphradium: DO, shortest distance between osphradium and edge of pallial cavity; FC, number of ctenidial filaments: HC, filament height; LC, length of ctenidium; LO, length of osphradium; ML, maximum length of раша! cavity; MM, minimum length of pallial cavity; MW, width of pallial cavity; WC, width of ctenidium; WO, width of osphradium. AAA AA AA Sex and №. LC WC FC AC HC LO WO DO CO ML MM mw F. accepta form A (Stations 002, 003, 752, 753) F Хх US) 0.50 31.54 0.21 0.20 0.45 0.11 0.34 0.28 1.88 1.09 1.31 (9) (10) (12) (12) (10) (13) $ 0.274 0.073 2.222 0.090 0.052 0.084 0.019 0.149 0.073 0.243 0.126 0.113 M x 1.46 0.52 30.85 0.23 0.20 0.41 0.12 0.33 0.27 1.84 1.09 1.24 (13) $ 0.224 0.069 2.911 0.063 0.027 0.083 0.026 0.150 0.060 0.328 0.122 0.093 Е. accepta form В (Stations 689, 690, 692, 694, 711) Е ESG 0.45 30.28 0.16 0.12 0.38 0.10 0.23 0.27 1.71 0.93 1.24 (17) (17) (17) (18) $ 0121 0.073 2.469 0.046 0.027 0.055 0.013 0.055 0.055 0.161 0.093 0.117 М ESO 0.47 28.83 0.16 0.12 0.37 0.11 0.23 0.23 1.59 0.88 1.20 (13) $ 0.124 0.058 2.368 0.044 0.029 0.033 0.014 0.049 0.064 0.120 0.095 0.099 Е. accepta form С (Station 703) Е х 1.69 0.49 32.50 0.13 0.26 0.43 0.10 0.12 1.39 1.96 1.01 1.48 (4) (4) (4) (5) s 0.19 0.034 2.380 0.041 0.023 0.026 0.011 0.006 0.126 0.256 0.073 0.149 М x 170 0.53 33.00 018 026 038 010 034 0.29 197 093 1.38 (3) (3) (3) (3) (3) (4) s 0.172 0.053 2.646 0.035 0.038 0.056 0.013 0.038 0.074 0.086 0.059 0.091 Е. адиайса form A (Stations 028, 030, 039, 679, 683, 720, 723, 739, 741, 747, 767, 771) Е me 59 0.45 34.49 0.22 0.15 0.39 0.12 0.35 0.27 1.97 1.07 1.49 (33) (33) (34) (24) (33) (33) (28) (29) (34) (33) (32) (35) s 0.260 0.138 4.529 0.100 0.039 0.103 0.023 0.079 0.090 0.346 0.350 0.367 M х 142 0.43 34.05 0.22 0.14 0.36 0.12 0.32 0.24 1.81 0.97 1.41 (20) (20) (20) (20) (15) (20) (20) (20) (21) (19) (19) (20) (22) s 0.247 0.167 5.596 0.075 0.040 0.031 0.025 0.067 0.107 0.273 0.224 0.316 Е. aquatica form A (typical form: Stations 028, 030, 039, 679, 720, 723, 739, 747, 771) F x 168 0.45 37.00 0.22 0.18 0.39 0.12 0.38 0.31 2.02 1.03 1.62 (18) (19) (11) (17) (16) (19) (18) (18) (20) $ 0.223 0.173 3.844 0.109 0.030 0.128 0.024 0.073 0.067 0.317 0.291 0.399 Мих 1.56 0452203782 022 0.17 037 0.11 035 030 198 102 156 GANAN Ca) Zei) (9) GLE Gays ANA AO) NO) IE at) (13) s 0.193 0.220 3.710 0.080 0.028 0.027 0.016 0.060 0.052 0.310 0.283 0.317 F. aquatica cf. form A (Stations 683, 741, 767, 771) F x 01:49 0.45 31.07 0.21 0.12 0.40 0.12 0.31 0.23 1.91 1201531 (14) (14) (13) (13) (13) (11) (13) (14) (15) s 0.267 0.074 2.868 0.090 0.029 0.046 0.024 0.075 0.100 0.381 0.416 0.232 M Хх 25 0.42 29.44 0.21 0.11 0.35 0.12 0.27 0.15 1.67 0.91 1.20 (8) (9) s 0.196 0.073 3.712 0.071 0.027 0.033 0.033 0.045 0.094 0.143 0.128 0.145 Е. aquatica form В (Stations 045, 046, 665) F Хх 56 0.49 33.25 0.18 0.16 0.37 0.12 0.29 0.35 1.82 1.10 1.33 ‚ (8) (8) (10) s 0.037 0.025 1.581 0.031 0.015 0.008 0.035 0.071 0.054 0.110 0.057 0.139 M x - 1.47 0.53 33.75 0.23 0.15 0.39 0.14 0.33 0.32 1.88 1.05 1.40 (8) s 0.146 0.019 2315 0.032 0.020 0.045 0.032 0.086 0.039 0.224 0.080 0.070 PP 128 PONDER, HERSHLER & JENKINS TABLE 18C. Fonscochlea accepta and F. aquatica, miscellaneous measurements. BM, length of buccal mass; CA, distance between ctenidium and anus; DG, length of digestive gland anterior to gonad; LD, length of digestive gland; LG, length of gonad; LS, length of snout; LT, length of cephalic tentacles; MA, shortest distance of anus from mantle edge; RS, length of radular sac behind buccal mass. Sex and No. LS LT LD DG LG BM RS CA MA F. accepta form A (Stations 002, 003, 752, 753) F X 0:57 0.48 3.42 0.66 WEA 0.76 1.42 0.57 0.76 (10) (10) (10) (6) (10) (4) (10) (10) (13) 0.128 0.078 1.026 0.360 0.472 0.058 0.19 0.132 0.217 ao M x 059 0.47 3.56 0.34 2.44 0.58 1.42 0.56 0.79 (10) (10) (10) (5) (10) (7) (10) (10) (13) s 0118 0.72 0.687 0.142 0.411 0.232 0.144 0.096 0.171 F. accepta form B (Stations 689, 690, 692, 694, 711) [= x 0.41 0.41 2.29 0.35 1.28 0.69 1.10 0.53 0.53 (5) (5) (5) (4) (5) (5) (5) (15) (16) s 0.053 0.090 0.401 0.092 0.119 0.104 0.124 0.102 0.090 M x 0.46 0.41 2.76 0.19 2.01 0.70 1.18 0.60 0.55 (4) (4) (4) (4) (4) (4) (4) (11) $ 0.154 0085 0.272 0057 0173 0047 0173 0110 9109 F. accepta form C (Station 703) F x 0.48 0.53 2.72 0.31 1.60 0.66 1.30 0.88 0.68 (4) (4) (4) (4) (4) (4) (4) (5) s 0.072 0.046 0350 0.087 0.158 0.7 0.095 0.094 0.144 М X 0.47 0.57 3.20 0.33 2.23 0.65 1.26 0.83 0.82 (4) s 0.078 0.078 0.304 0.47 0.209 0.063 0.279 0.138 0.142 F. aquatica form A (Stations 028, 030, 039, 679, 683, 720, 723, 739, 741, 747, 767, 771) 5 x 0.63 0.55 3.23 0.46 1773 0.99 1.61 0.65 0.74 (23) (24) (26) (26) (28) (24) (30) (22) (22) (35) s 0.108 0.160 0.631 0.138 0660 0.067 0.244 0.163 0.180 M x | 0.58 0.48 2.93 0.41 1.98 0.93 153 0.60 0:77 (16) (17) (17) (17) (18) (17) (19) (18) (18) (22) s 0.09 0.109 0.723 0.100 0.49 0.79 0.193 0.185 0.222 F. aquatica form A (typical form: Stations 028, 030, 039, 679, 720, 723, 739, 747) F x 0.65 0.62 3.47 0.47 2.00 0.95 1:61 0.58 0.74 (10) (12) (17) (17) (19) (12) (19) (10) (9) (20) s 0.143 0.180 0.498 0.109 0.642 0.042 0.235 0.105 0.103 M x 0.61 0.52 3.47 0.45 2.43 0.95 1.57 0.65 0.86 (7) (8) (8) (8) (9) (8) (10) (9) (9) (11) 5 0.09 0.099 0.476 0.099 0.518 0.031 0.199 0.209 0.269 Е. адиайса cf. form A (Stations 683, 741, 767, 771) Е X 0.61 0.49 2.79 0.45 1.23 1.03 1.61 0.71 0.75 (13) (12) (9) (9) (9) (12) (12) (12) (13) 0.072 0.109 0.635 0.188 0.299 0.062 0.127 0.183 0.223 mn (15) M x 0.56 0.43 2.45 0.38 1.53 0.91 1.49 0.55 0.69 (9) 5 0.092 0.106 0.546 0.096 0412 0.104 0189 0.153 0125 Е. адиайса form В (Stations 045, 046, 665) Е X +0155 0.56 3.19 0.60 1.29 0.89 1.71 0.74 0.59 (8) (8) (8) (6) (6) (10) 5 0.075 0.117 0.408 0.036 0.165- 0.052 0.188 0056 0.084 М x 0.54 0.54 3.11 0.52 1.86 0.83 1.48 0.73 0.70 (8) $ 0.085 0.148 0.509 0.111 0.191 0.085 0.082 0.113 0.093 AUSTRALIAN SPRING HYDROBIIDS 129 TABLE 18D. Fonscochlea accepta and F. aquatica, stomach and male genital measurements. AS, height of anterior stomach chamber; PL, length of penis; PP, length of pallial portion of prostate gland; PR, length of prostate gland; PS, height of posterior stomach chamber; PW, width of prostate gland; SL, length of stomach; SS, length of style sac. D FB ЧИ Sex and No. SL SS AS PS PL PR PW PP F. accepta form A (Stations 002, 003, 752) E x 1.05 0.61 0.72 0.63 (10) $ 0.333 0.085 0.124 0.066 М X 0.95 0.55 0.64 0.53 2.66 0.52 0.33 0.10 (7) (10) $ 0.383 0.102 0.081 0.046 0.593 0.108 0.046 0.086 Е. accepta form В (Stations 692, 711) F x 0.73 0.50 0.65 0.51 (5) 5 0.073 0.024 0.085 0.060 M x 0.69 0.47 0.61 0.53 1579 0.46 0.29 0.08 (4) 5 0.082 0.061 0.094 0.095 0.311 0.079 0.054 0.021 Е. accepta form С (Station 703) Е x 0.98 0.49 0.66 0.65 (4) 5 0.052 0.064 0.053 0.032 М x 0.90 0.49 0.66 0.64 232 0.55 0.25 0.10 (3) (3) (4) $ 0.102 0.012 0.048 0.078 0.184 0.089 0.035 0.042 Е. адиайса form A (Stations 028, 030, 039, 679, 683, (Stations 039, 683, 720, 723, 739, 120, 723, 739, 741, 747, 767, 771) 741, 747, 767, 771) Е x 1.14 0.69 0.85 0.69 (31) 5 0.402 0.108 0.156 0.153 М x 0.96 0.61 0.77 0.65 2.33 0.51 0.35 0.11 (16) (18) (13) (14) (12) (12) (18) 5 0.286 0.114 0.126 0.124 0.743 0.114 0.065 0.089 Е. aquatica form A (typical form: Stations 028, 030, 039, 679, 720, 723, 739, 747, 771) F (18) M (15) F (13) M (9) F (10) M X 1.32 0.74 0.91 $ 0.439 0.078 0.160 x 1513 0.66 0.85 (7) $ 0.262 0.093 0.150 Е. aquatica cf. form A (Stations 683, 741, 767) x 0.89 0.61 0.77 5 0.120 0.093 0.106 x 0.79 0.56 0.70 $ 0.193 0.113 0.049 Е. aquatica form В (Stations 045, 046, 665) x 1.09 0.69 0.77 5 0.111 0.052 0.072 x 1.12 0.70 0.79 5 0.044 0.034 0.013 (8) 0.75 0.148 0.73 0.063 0.60 0.117 0.57 0.122 0.70 0.068 0.74 0.051 (Stations 039, 720, 723, 739, 747, 771) 2.04 0.43 0.30 0.10 (5) (5) (5) (4) 0.320 0.073 0.048 0.038 2.87 0.56 0.34 0.11 0.178 0.019 0.071 0.012 PONDER, HERSHLER & JENKINS 130 РИ 0 8100 1210 0 8000 900 $900 8100 S200 0 уго 8200 200 2600 8900 $ (or) (9) (8) (8) (8) (8) (8) (8) (2) (8) (8) (9) (9) (9) soo EEO eo"! 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"980 MELON REIN 551 3 (150 UONe1S) 4 WO} $//емел ‘+ a a ———+—+—=———— == — _——— — 6700 4690 Iÿl'O 16,0 ZIEO0 $860 > 790`0 #100 7:00 24900 ¿040 2500 6600 == 1100 5570 ¿eso $ (2) = 550 050 520 sc | 890 er! => 6,0 ого ¿30 020 0502 020 92.0 => ЕО 151 Et xX MN pa AA AAA ee ee ene eee CR ЕЕ ЕЕ АЕ EE RQ ST AAA Ta PR Fr en 2600 ELLO 9910 6910 EcEO = — y er00 €200 2100 1200 979% 8500 EELO D — 6550 28801555, (€) (2) (€ (г) (2) (1) Ovo ISO $0 06 0 vo"! = = — 910 gro 0c 0 120 002 610 vZ'0 — 910 080 сер x 3 (y LO ‘800 SUONEIS) Y WHO} $//демел Y _ + + e + + + + + + + + + + + + + + + + + + + + ++ A m Sd sv Ss 1S MW WW IN O9 oa OM O1 OV 94 OM 91 SH 90 91 al "ON Y X9S CORA SE E AP AO Е SS A A AA A AA Е "uwnipesydso jo щрим ‘OM ¿unipiuajo JO YIPIM ‘OM :9е$ ajAjs jo y¡bua] ‘SS ‘oes э/}$ + yoeulo]s jo y¡Bua] ‘JS ‘ssew |еээпа рицеа oes лепрел jo щбиз| ‘Sy ‘лэашецо цэешо}$ Jonajsod jo зубец “Sd ‘Аилеэ jeijjed JO UIPIM ‘MW ‘Аилеэ jeijjed jo чбиа| пеши ‘WW ‘Аулеэ 1ещед yo Puel jewixew yy ‘шигирелиаво jo yyBua] ‘07 !peuoß jo yyBua] ‘97 :риеб anısaßıp jo uBuel ‘ал “wnipiuajo jo y¡Bua] ‘97 ‘зиэшец ¡eipiuazo jo лэашпи ‘94 ‘Айлеэ |ещед jo эбрэ pue winipeiydso usamjaq aouej]sip 1зэроцз ‘OQ :peuob о Jonajue риеб элцзэбр jo y¡Bua] ‘Эа ‘шпирша jo di 1oueysod pue wnipeiudso jo di л0иэ}504 изэмеа aouejsip ‘OD ‘лэашецо yoeuojs Jonajue jo }yBieu ‘Sy ‘шпршер JO щрим ‘OY ‘зиэшелзеэш yoeuo]s pue jeijjed 'snoauejjaosiu ‘еошоэ “Y pue eureyejig “Y 'SiIgeuen eajy909suoy "961 AIGVL PONDER, HERSHLER & JENKINS 134 9900 1210 2c£'0 (6) velo €+l'O 2000 5000 0010 6100 ZEOO 2200 8200 0E00 1200 8800 +010 9910 S (6) (2) (8) (2) (2) (8) (+) (8) (8) (8) (8) (8) 60 0 6c 0 180 W 910 57'0 50`0 S0'0 65'0 50'0 LLO LLO +00 ГЕО со ce 0 570 920 Хх S| (87/'500 suone]s) (8r2 'v20 ‘020 ‘200 ‘600 SUONEIS) pomos y gL00 SZ00 070'0 (€) 1600 8950 9000 E100 6350 == 2200 200 200 920`0 6r00 85910 9920 z8so $ (5) (p) (2) (+) (+) (+) (+) (+) ЕО tt 0 LUE W £L'O 850 70`0 20'0 бет 900 Sr 0 8r0 200 ЕО 020 99'0 260 87 x = (92 uone]s) (620 ‘920 SuorelS) eureyejig y (1) (1) 65'0 6v'0 951 W 60 66 0 70`0 —= 1200 10`0 91.0 5<'0 r00 910 £c 0 950 £8 0 6€'! =| (270 uonels) 9 шло} /идеиел y (1) И 610 5590 90€ N 610 ect $00 100 560 100 90 510 600 90 510 $590 580 Yrı 4 (LEO ц04е}5) Я WHO} /идемел ‘+ 8200 2600 16L'0 (г) EILO 5520 2000 Er00 velo S000 9100 9b0'0 — 0800 6200 12400 1200 0 $ (5) (г) (2) (2) (€) (€) (2) (2) (2) 150 590 Ort N 150 050 200 LEO 180 +00 010 610 — GLO 020 $70 ELO р ХЗ (pLo uonels) (FLO ‘800 SUONEIS) Y WO SyIgeuen y dd Hd qd ‘ON sg ON ON ла AO Ha HM us ga gm 98 Ov 99 O9 ‘ON Y X2S 2xX9S „'9l0e}d9984 ¡euluas,, Jo yjpim “ym ‘хщепдоэ esinq jo щрим ‘QM чэчциецо |[едиал jo uoluod 284 jo yjbua] ‘ЭЛ :..э2е}9аээ/ jeunuas,, jo yyBua] ‘YS ‘риеб aeyeysoid jo uBuel ‘Hd :pue¡6 eyeysoid jo чощод |ещеа jo цбиз| ‘44 ‘siuad jo y¡bua] “14 ‘JONPIAO jo чоцао4 pajio9 jo 1лэзэшер |пецииш ‘ON зопрмо леприе!б jo чзбиа| ‘OD “jonpino jo UOIPOd pajio9 jo JayoweIP |ецихеш ‘ла :эюе9аээл ¡eunuas,, jo jonp jo цзбиг|! ‘Ha ¿xujejndoo esinq jo jonp jo yjBua¡ ‘аа :jonpino jo uonuod ра|оэ jo yyBua] ‘AD ‘pue ajnsdeo jo fuel] ‘99 ‘хщепаоэ esinq pue ajoejdaoa, jeuluas,, иээмцаа JONPIAO jo yjBua] ‘Sg 'xiuyejndos esinq jo y¡Bua¡ ‘Og 'pue¡B чэшпае jo yjBua] ‘Hy ‘sjuawainseaw |еиэб ajew pue эеша} ‘вэшоэ ‘+ pue вицеуе/иа ‘4 ‘SIIIQEUEA eay909suoy ‘961 AIGVL 135 AUSTRALIAN SPRING HYDROBIIDS am u А 1860 9€0'0 1€0'0 €90°0 0 21500 0 9200 6+0'0 cel 0 ANNO) 680'0 O£L'0 681'0 $ (SL) (e1) (EL) (EL) (EL) (1) (2) (2) (5) (5) Sse seo 62°0 Leb 55`0 00€ 09° 810 E61 892 2611 8971 122 Lee x N ySZ'0 750`0 6200 990'0 = 991'0 910'0 €£0'0 6S0°0 6010 2010 960`0 910`0 LLO $ (12) (02) (02) (02) (02) (OL) (01) (5) (5) Ore 75'0 05`0 Lek = 60'€ LoL 10 961 292 Zeb 291 ее 9v'€ x 4 (199 uoNeIS) g WO} He/pIeZ y GLO'L r20'0 2v0'0 8LL'O 270'0 $15`0 290`0 770`0 881'0 8220 0910 8rl'0 S62°0 1970 $ (121) (201) (z01) (201) (гор) (LL) (911) (211) (9p) (9p) 20 + 65'0 25`0 ge 25`0 255 ISL 91'0 soz sz 91 es! 922 99'€ x N 16/`0 G90'0 9v0'0 8LL'O 770`0 +62`0 690'0 S€0'0 L91'0 9920 6810 9S1'0 182°0 855`0 $ (251) (001) (001) (001) (001) (611) (611) (611) (0€) (0€) Z0'p 65`0 Le'0 gel 59`0 Sse zst 810 202 832 Sr 99| ze 69€ x 4 (1ZZ ‘SSZ 'LpZ ‘p69 ‘149 ‘+99 ‘050 ‘820 ‘620 ‘PZO ‘BLO “LLO SUONEIS) y шло} L8/plez y Nd Od Hd 10 Gd ML Md A9 gm ма МУ НУ MS HS ‘ON pue xas __ AAA A A AA A A A A nt A PNTE ‘HOUM Apog JO JIOYM-J¡8y 131} JO YIPIM ‘M :SHOUM U9U090818} JO saquinu ‘ML “yipim pays ‘MS зубец IIeys ‘HS ‘SHOUM U9U090]o1d jo saquinu ‘Ма ¿sBad леполэдо jo 1equunu ‘ма ¿Bad леполэдо sale} jo зубец ‘На :y9U090J01d Jo y¡bua] jewixew ‘аз ‘изодэр snoajeojeo jo y¡Bua] ‘Эа ‘шпполэао jo Puel ‘10 ‘HouM ajeunnuead.jo Айхэлиоэ ‘AD ‘роцм Ápoq jo цбиг| ‘Mg :yipim ainuede ‘MY “ybiey einuede ‘НУ ‘зиэшалзеэш леполэдо pue |jeys ‘Je/plez Bejy909suoy ‘WO? 3718WL 136 PONDER, HERSHLER & JENKINS TABLE 20B. Fonscochlea zeidleri, pallial measurements. AC, width of ctenidium from left side to position of filament apex; CO, distance between posterior tip of osphradium and posterior tip of ctenidium; DO, shortest distance between osphradium and edge of pallial cavity; FC, number of ctenidial filaments; HC, filament height; LC, length of ctenidium; LO, length of osphradium; ML, maximal length of pallial cavity; MM, minimal length of pallial cavity; MW, width of pallial cavity; WC, width of ctenidium; WO, width of osphradium. Sex and No. LC WC FC AC HC LO WO DO CO ML MM MW F. zeidleri form A (Stations 011, 013, 018, 024, 026, 028, 030, 034, 039, 046, 694, 742, 766, 771) F x 143 043 26:68: 0.19 0811 0.44 0.12 0.28 0.30 2.05 1.02 1.49 (32) (33) (31) (16) (31) (32) 7 (260) (23) 025) (2) 2 (34) s 0.365 0.136 3.042 0.088 0.039 0.125 0.034 0.088 0.094 0.427 0.364 0.438 М x 128 043 2542: 020 0'08 0.387 051377 0,2772 029772 1166530193147 (23) (23) (24) (23) (12) (22) (22) (18) (22) (21) (19) (21) (25) s 0.355 0.164 3.175 0.105 0.023 0.139 0.086 0.095 0.124 0.414 0.223 0.368 F. zeidleri form B (Station 661) F x 126 037 23.20 0.14 012 036 009 031 028 1.59 091 129 (5) $ 0.171 0.069 0.837 0.048 0.038 0.038 0.007 0.082 0.024 0.225 0.084 0.142 M x 123 033 2400 015 0.14 035 04977 0.30) 10:28) 1.511 1019530031 (4) $ 0.115 0.039 1.633 0.012 0.035 0.021 0.025 0.030 0.057 0.183 0.197 0.138 TABLE 20С. Fonscochlea zeidleri, miscellaneous measurements. ВМ, length of buccal mass; СА, distance between ctenidium and anus; DG, length of digestive gland anterior to gonad; LD, length of digestive gland; LG, length of gonad; LS, length of snout; LT, length of tentacles; MA, distance of anus from mantle edge; RS, length of radular sac behind buccal mass. Sex and No. LS LT LD DG LG BM RS CA MA F. zeidleri zeidleri (Stations 011, 013, 018, 024, 026, 028, 030, 034, 039, 046, 694, 742, 766, 771) Е x 053 0.38 3.27 0.45 1.50 0.74 0.87 0.47 0.40 (18) (18) (27) (24) (26) (18) (27) (16) (15) (34) $ 0.100 0.076 1.050 0.23 0.640 0.105 0.136 0.137 0.150 M x 0.48 0.35 3.52 0.33 2.46 0.63 0.83 0.57 0.33 (13) (13) (22) (22) (22) (13) (21) (17) (12) (27) s 0.78 0.80 0.771 0.100 0.852 0.124 0.164 0.234 0.083 F. zeidleri form B (Station 661) x 0.45 0.41 3.00 0.38 1.55 0.63 0.84 0.49 0.43 (5) 5 0.065 0.075 0.245 0.065 0.36 0.046 0.061 0.080 0.071 x $ 0.45 0.38 2.5] 0.32 1.48 0.63 0.90 0.48 0.40 0.021 0.055 0255 0116 0.219 0.067 0.104- 0.118 0.096 AUSTRALIAN SPRING HYDROBIIDS 137 TABLE 20D. Fonscochlea zeidleri, stomach and male genital measurements. AS, height of anterior stomach chamber; PL, length of penis; PP, length of pallial portion of prostate gland; PR, length of prostate gland; PS, height of posterior stomach chamber; PW, width of prostate gland; SL, length of stomach + style sac; SS, length of style sac. Sex and No. SL Ss AS PS PIE PR PW PP Е. zeidleri form A (Stations 011, 013, 018, 024, 026, 030, (Stations 011, 018, 024, 034, 039, 034, 039, 046, 694, 742, 766, 771) 694, 742, 766, 771) F x 1.02 0.71 0.81 0.68 (17) (27) (20) (25) (28) $ 0.320 0.151 0.143 0.138 М x 0.93 0.70 0.74 0.64 1.83 0.65 0.37 0.14 (14) (22) (19) (19) (23) (24) (17) (23) (24) $ 0.377 0.168 0.177 0.133 0.537 0.290 0.129 0.119 Е. zeidleri form В (Station 661) Е x 0.83 0.69 0.68 0.64 (5) 5 0.040 0.072 0.050 0.028 М x 0.82 0.69 0.68 0.63 1.59 0.56 0.32 0.14 (3) (4) $ 0.025 0.064 0.062 0.044 0.113 0.047 0.060 0.082 TABLE 20Е. Fonscochlea zeidleri, female genital measurements. AG, length of albumen gland; BC, length of bursa copulatrix; BS, length of oviduct between “seminal receptacle” and bursa copulatrix; CG, length of capsule gland; CV, length of coiled portion of oviduct; DB, length of duct of bursa copulatrix; DR, length of duct of “seminal receptacle”; DV, maximal diameter of coiled portion of oviduct; GO, length of glandular oviduct; GP, length of genital opening; MO, minimal diameter of coiled portion of oviduct; SR, length of “seminal receptacle”; VC, length of free portion of ventral channel; WB, width of bursa copulatrix; WR, width of “seminal receptacle”. Sex and No. GO CG AG BC WB DB SR WR DR CV DV MO VC BS GP F. zeidleri form A (Stations 011, 013, 018, 024, 026, 030, 046, 694, 742, 766, 771) F x 155 0.86 0.72 0.24 0.22 0.099 0.31 0.24 0.10 1.56 0.11 0.06 0.47 0.15 0.07 (25) (25) (26) (27) (27), (27) (26) (22) (25) (27) (20 126) (17) (28) s 0.467 0.246 0.220 0.071 0.048 0.031 0.122 0.079 0.057 0.261 0.022 0.011 0.104 0.053 0.020 F. zeidleri form B (Station 661) F x 1.49 0.80 0.68 0.20 0.18 0.04 0.23 024 0.09 1.26 0.09 0.05 0.40 0.15 0.05 (4) (4) (4) (5) s 0.132 0.082 0.055 0.017 0.006 0.011 0.023 0.041 0.020 0.071 0.011 0.005 0.028 0.023 0.005 138 PONDER, HERSHLER & JENKINS TABLE 21A. Trochidrobia species, shell measurements. AH, aperture height; AW, aperture width; BW, length of body whorl; PD, maximal length of protoconch; PW, number of protoconch whorls; SH, shell height; SW, shell width; TW, number of teleoconch whorls. Sex and No. SH SW AH AW BW PW TW PD T. punicea (Stations 002, 007, 008, 022, 025, 027) F x 1.43 1.74 0.80 0.80 1.26 1.48 1.97 0.37 (83) (90) (95) 5 0.136 0.263 0.085 0.068 0.136 0.073 0.145 0.038 М x 1:35 1.64 0.77 0.75 1.18 1.48 1.86 0.36 (34) (36) $ 0.145 0.104 0.068 0.059 0.128 0.059 0.143 0.041 Т. smithi (Stations 033, 038) E x 1.48 1.80 0.86 0.85 1.30 1.50 1.92 0.41 (26) $ 0.167 0.145 0.062 0.061 0.165 0.072 0.117 0.035 М x 1.48 1.80 0.85 0.83 1.30 1.50 1.92 0.40 (19) 5 0.153 0.122 0.058 0.056 0.113 0.046 0.119 0.030 T. minuta (Station 045) Е x 0.69 1510 0.44 0.47 0.61 1.46 1.43 0.33 (11) 5 0.061 0.052 0.036 0.026 0.054 0.081 0.085 0.029 0.72 1.10 0.44 0.47 0.64 1.43 1.47 0.34 (12) 0.092 0.070 0.035 0.033 0.077 0.098 0.054 0.033 X 5 T. inflata (Station 043) X 5 Е doit 1.53 0.86 0.81 1.26 1.50 1.95 0.41 (11) 0.172 0.170 0.105 0.084 0.155 0 0.204 0.017 M x 1.43 1.45 0.80 0.75 1.18 1.53 1.89 0.42 (11) $ 0.140 0.140 0.056 0.064 0.128 0.090 0.140 0.024 139 AUSTRALIAN SPRING HYDROBIIDS 200 9010 200 0210 ИО 9600 2910 SEOO 1500 120`0 000 000+ 2200 8/00 6700 1200 4400 9010 9210 $ (e) a a a ( (2) а - veo 80 250 peo. ИЕ 60 tot 610 ero 800 130 — 0003 120 00, 920 220 600 Ep er Leila и 5800 5700 8100 $5210 0210 $210 1200 0800 +900 0100 9100 — WIE 200 9800 ¿aro 0 000 0590 — $ (у) (5) (5) (5) (2) (5) (2) (5) (5) (5) (5) (5) (2) (2) (5) (1) 070 oso seo 680 Zit 990 901 го zo oro seo — 0005 920 760 220 (020 050 20 9 x 3 ($70 “EVO SUONEIS) ввуи! 1 0500 8/00 9/00 0200 S200 1600 5950 0700 5700 5100 $7700 — 42860 7900 с/1'0 8500 9:00 5700 9120 ¿bdo $ (S) (€) (5) (€) (5) (+) (5) (+) (5) (+) (г) (г) (2) 190 20 90 800 ¿o — 082 0 950 oro 0110 90 880 ect X N SP00 6820 $ (5) 6600 zoo 9100 E200 2500 — 8200 2600 2v00 1200 0 8287 8200 1/00 (г) (2) (1) (2) (2) (2) (2) (2) (2) (г) (2) (2) (г) (г) (5) (2) ezo 920 veo 250 020 10 790 0 ero 800 90 — 00% rio. 850 800 ¿HO 520 950 201 x 3 (670 “evo suonels) алии ‘1 110 8700 1700 8600 8220 6800 2920 9700 #500 9100 vedo #100 2610 $010 0500 2500 690 8/50 $ (8) (y) (p) (y) (y) (y) (s) (5) (9) (9) (2) (2) (2) (2) (2) (y) (v) (y) (y) ($) yo seo 880 sit oso 560 810 oro 800 20 20 0002 920 160 200 91:0. 08:07 Е we x и 8700 1500 8500 500 4220 1900 8720 /700 $5500 5100 0700 1500 8261 800 seo 1/00 6700 9600 OELO 6370 $ (p1) (6) (ot) (or (or) (11) (ol) (zi) (Gp (el) (el) (2) (op (© (< (6) (os) (Ob) (6) 250 970 peo 160 61: ISO 960 gro 90 800 po 920 661 8560 360 veo 020 Mo 650 691 X 3 (12/ ‘189 ‘6/9 '6€0 '8EO ‘ZE0 ‘650 ‘620 “420 $и048}5) /4иш$ `1 6100 €600 0600 6170 LLLO 6700 8120 6200 roo 1200 6500 1900 2655 9500 HELO 9010 170`0 6800 6950 65970 $ (8) (+) (2) (9) (2) (2) (9) (2) (9) (2) (9) (2) (+) (2) (9) (2) (5) (9) (9) (9) vo ovo 550 8/0 560 geo 280 oro sto 800 SEO 2.0 698%: 130 640 2460 [60 “Scio, 680 Их W а ee eS ae 8500 0900 0900 $910 6rl0 УГО volo 0500 9600 0E0O 1200 1200 69€ 2 4700 L610 1600 2500 2210 423880 1550 $ (01) (2) (2) (2) (2) (6) (4) (2) (2) (6) (6) (+) (6) (6) (5) (5) (8) (2) 2€ 0 sro 570 vol 501 970 080 bro 910 600 950 150 056: zo 980 620 550 570 080 002 X 3 (82 ‘569 ‘vZ0 ‘050 ‘600 200 "200 suonejs) Baoıund 1 Sd SV ss 715 ми WW ли O9 od OM 01 OV 91 VO SH 9d on al ‘ON Y X9S -wnıpeaydso jo цурим ‘OM “UINIpIuayo JO UIPIM ‘ЭМ ‘92$ as jo uiBuel ‘SS ‘ges э!А}$ + YORWO}S jo y¡Bua¡ ‘1$ !ssew ¡eoonq pulyeq des Jenpei jo y¡bua] ‘SH ‘лэашецо 42241945 souaysod jo 1ybiay ‘ба ‘Ayaeo ¡enjed Jo UIPIM "MIA ‘Килеэ ¡eyed jo щбиа| jewiumu WW ‘Аилео jeijjed jo y¡Bua] ецихеш IN ‘wunipesydso jo yybua] ‘07 ‘peuoß jo y¡bua] ‘97 ‘pue|6 anısaßıp jo цщбиа! ‘ал ‘шпиршер JO fuel] ‘97 ‘зиешец ¡eipluajo JO Jequunu ‘94 ‘Ares jeijed jo abpa pue unipesydso иээмэа эоиезз!р ISOHOUS ‘Og :peuo6 0} 1OH8JUE рие!б элцзэб!р jo uiuel ‘HA “unipiuayo JO dy Jouajsod pue wnipeiydso jo dy Jouajsod uaamjeq aoue]sip ‘OD “snue pue шгирше чээмеа SOUEISIP YO ‘чеашецо yoewojs ломацие jo jubiay ‘Sy -WNIpIUSP jo щрил ‘OW ‘зиэшелзеэш ц9е\191$ pue snoour||aosiw ‘eyed ‘зэюэ4$ e/qo/ply901L "ALT JIaVL PONDER, HERSHLER & JENKINS 140 120'0 — 150'0 0 (€) ÿLO‘0 0 $10'0 0610 0 520`0 520`0 5910 8LL'O 820 0 $ (+) (г) (г) (г) (г) (5) (г) (€) (€) 0—0 — 60 180 W ого r0°0 90'0 050 г0`0 ЕО 810 ct 0 55'0 eo'! x 3 (pO “EVO SUONEIS) веци! 1 200`0 = 590`0 901'0 (+) 0200 0 900'0 +OL'O 2000 9000 210`0 GG0'0 990'0 260`0 $ (5) (г) (г) (г) (г) LL'O — 120 95'0 W te’ 0 50`0 r0'0 LG'O г0`0 60'0 10 0€'0 Ze'0 €e9'0 x 4 (SO “evo $40815) влиш y 650'0 0 SZ0'0 660`0 (8) 6500 500`0 LLO'O 680'0 7100 9500 1200 8010 590 961'0 $ (Gi) (9) (г) (+) (6) (OL) (11) (yh) (p1) (rı) 910 LEO 67'0 89°0 W 90'0 vO0'0 90'0 6/`0 50'0 ЕО 910. 2590 87'0 66'0 x 4 (649 ‘660 ‘850 ‘/50 ‘580 SUONEIS) (122 ‘189 '6E0 ‘8E0 'ZEO ‘980 ‘EEO ‘220 SUONEJS) {JWS ‘1 LEOO 0900 G60'0 9210 (01) 0910 pLOo0 $50'0 5520 760 2800 901'0 0€Z'0 081'0 0pZ'0 Ss (OL) (2) (+) (2) (9) (2) (8) (8) (6) (6) (6) 610 92:0 Kon) 90'1 N veo S0'0 ero er 120 020 820 190 55'0 er! x 4 (871 ‘569 'v20 ‘600 “¿OO SUoNeIS) (569 ‘020 ‘600 ‘200 ‘200 SUONeJS) Baoıund | dd Md Hd qd ‘ON Y хэ$ ON OW ла A9 ga gm 94 OV 99 09 ‘ON 8 xas ‘Xujendo9 esing jo щрим ‘ам чечиецо |едиэл jo uoiuod 984} jo цбиа| ‘Эл ‘риеб ayeysoud Jo цурим ‘Ма ‘puelB ajejsoud jo щбиа! ‘Hd ‘pue|6 ejeysoid jo uonuod |ещед jo щбиа| ‘qq ‘siuad jo Buse] “14 ‘JONPIAO jo uoiuod pajio9 jo JaJeWeIP jewiumu “ON {JONPIAO леприеб jo цзбие! ‘OD ‘JONPIAO jo UOINOd pajioo jo Jajawelp jewixew ‘ла ‘хшепдоэ esing jo jonp jo чзбиз| ‘аа “jonpino jo uoiuod раоэ jo yyBua] ‘AD ‘puelB ajnsdeo jo y¡bua] ‘99 ‘хщепадоэ esinq jo yyBua] ‘Эа ‘puelf иэшпае jo цбиз| ‘oy ‘ззиэшэлзеэш |ериэб ajew pue эеша} ‘saiseds ergo4piyoouL ‘912 AIGVL MALACOLOGIA, 1989, 31(1): 141-156 ULTRASTRUCTURAL CHANGES IN THE DIGESTIVE TRACT OF DEROCERAS RETICULATUM (MULLER) INDUCED BY A CARBAMATE MOLLUSCICIDE AND BY METALDEHYDE R. Triebskorn Zoologisches Institut I, Universität Heidelberg, Im Neuenheimer Feld 230 D-6900 Heidelberg, F.R.G. ABSTRACT Electron microscope investigations reveal different reactions of cells in the digestive tract of Deroceras reticulatum to intoxication with carbamate or metaldehyde molluscicides. All entero- cytes are more strongly attacked by the carbamate compound Mesurol than by metaldehyde. The better efficiency of Mesurol is primarily attributed to its severe impact on nuclei, leading to other cell damage and finally to an increased macrophage reaction. Metaldehyde leaves the enterocyte functions more or less intact except for that of mucus cells. It activates mucus extrusion immediately after the onset of intoxication. This mucus serves to dilute the toxin, which passes through the digestive tract and is voided. The severe attack of metaldehyde on the immature mucus cells results in cessation of mucus production, leading to a fatal mucus deficiency in the digestive tract. Key words: Gastropoda; molluscicides; carbamate; metaldehyde; digestive tract; ultra- structure INTRODUCTION To date, the most efficient pesticides against slugs are carbamate compounds, such as Mesurol, which act as nerve toxins by inhibition of the cholinesterase activity (Getzin & Cole, 1964; Pessah & Sokolove, 1983). Dur- ingthe last decade, Mesurol has replaced met- aldehyde as the primary commercial mollus- cicide, because metaldehyde loses most of its efficiency in humid climates (Martin & Forrest, 1969). In the literature (Pappas et al., 1973), however, it is not only Mesurol but also such other carbamate compounds as Carzol, Furadan and Zectran that are mentioned as having an increased efficiency compared to metaldehyde (Getzin, 1965; Prystupa et al., 1987). Whereas in most investigations LDso tests are used (Bakhtawar & Mahendru, 1987), there are only a few publications con- cerning cellular mechanisms induced by mol- luscicides (Ishak et al., 1970; Ваппа, 1977, 1980a, b; Pessah & Sokolove, 1983). Uptothe present, little attention has been paid to the fact that both carbamate compounds and met- aldehyde are in use as oral toxins (cf. Hend- erson, 1969), and, as a consequence, the first possible targets for molluscicidal action might be the cells of the intestinal epithelia. 141 In fact, only one study covers the influence of molluscicidal agents on the cells and tis- sues of the alimentary tract of slugs after in- toxication (Manna & Ghose, 1972). To the best of my knowledge, ultrastructural investi- gations are completely lacking. Thus, the present electron microscope study was de- signed to investigate the different cellular re- sponses to molluscicidal intoxication in the di- gestive tract of the grey garden slug, Deroceras reticulatum. A further purpose of the paper is to elucidate the reasons for the superior efficiency of carbamate mollusci- cides by comparing the ultrastructural dam- age after oral application of carbamate and metaldehyde. MATERIALS AND METHODS Laboratory-reared specimens of Deroceras reticulatum were fed pellets containing 4% of the carbamate compound Mercaptodimethur (4- (methylthio) -3,5-xylyl-methyl-carbamate; Mesurol; Bayer) or 4% metaldehyde (Spiess Urania 2000). The pellets were weighed be- fore and after the slugs had fed, and the amount of toxicant effectively ingested was calculated. On an average, the animals took 142 TRIEBSKORN up 200 ug Mesurol or 9 mg metaldehyde/g wet weight. Animals fed carbamate were dis- sected after one, five and 16 hours. The met- aldehyde group was fixed after five hours. For primary fixation a 2% glutaraldehyde solution in cacodylate buffer (0.01 M, pH 7.4) was in- jected into the body cavity. Then oesophagus, crop, stomach, intestine and digestive gland were isolated in fixative and fixed for two hours in 2% glutaraldehyde at 4°C. The tis- sues were rinsed in cacodylate buffer and postfixed in 1% osmium-ferrocyanide (Kar- novsky, 1971) for two hours. After rinsing in cacodylate and 0.05 M maleate buffer (pH 5.2), the specimens were stained en bloc in 1% uranylacetate in 0.05 M maleate buffer overnight at 4°C. The samples were dehy- drated and embedded either in Araldite or in Spurr’s medium (Spurr, 1969). Ultrathin sections cut on a Reichert ultrami- crotome were counter-stained with lead ci- trate for 30 minutes and finally examined in a Zeiss EM 9. RESULTS Macroscopic observations The macroscopic reactions of the animals af- ter molluscicide application correspond to the reactions described as typical for carbamate or metaldehyde intoxication by Godan (1979). By 30 minutes after ingestion of Mesurol pel- lets, the animals show violent muscle convul- sions. The anterior body begins to swell while the posterior flattens. The tentacles are re- laxed, the animals release а lucid mucus and take up liquid from the environment. After three hours they lie almost motionless on one side. Usually they die 20 to 30 hours later, but recovery is also possible. After the application of metaldehyde, the animals lose much more slime than after car- bamate ingestion. In this case, muscle con- vulsions and relaxation of the tentacles could not be observed. Electron microscopical investigations Histology of the epithelia in control animals Oesophagus: The oesophageal epithelium consists of four cell types, three of which reach the lumen (Fig. 1a): Туре |: Columnar storage cells (Figs. 2a, 5) characterized by high amounts of lipid and storage carbohydrate (glycogen or galacto- gen) (Fig. 34). In the central cytoplasm, the nucleus, small Golgi complexes, mitochon- dria and a few peroxisome-like vesicles are located, while smooth and granular endoplas- mic reticulum occasionally appear in basal re- gions of the cells. Under the microvillous bor- der a band of mitochondria can be found (Fig. 10). Type Il: Columnar secretory cells of an ec- crine type (Fig. 1a), with basally situated granular endoplasmic reticulum and an elab- orate Golgi apparatus (Fig. 29) producing electron-lucent secretory vesicles. Mitochon- dria and small amounts of lipid and glycogen are dispersed over the cytoplasm. The nu- cleus is located in the center of the cell. Type Ш: Secretory cells of a holocrine type (mucus producing goblet cells, in the follow- ing called “mucus cells”) (Figs. 1a, 3a, 5, 25), with conspicious granular endoplasmic retic- ulum characterized by a spacious lumen, large Golgi apparatus and mucus vacuoles that merge in the apical part of the cells. The nuclei of these cells are situated in the basal, dilated regions. Young mucus cells (Fig. 3a) do not contain high amounts of mucus vacu- oles and are characterized by a conical cell shape. Type IV: Small electron-lucent cells (Fig. 5), conical in shape, that are dispersed amongst the other cells. Their apices do not reach the lumen. Containing characteristic lysosomes, dictyosomes and a prominent nucleus, they resemble the haemolymph macrophages. The basal surfaces of all cell types have no infoldings (Fig. 5). In addition to numerous mi- crovilli, the luminal surface of cell types | and II may bear cilia (Fig. 2a). The microvilli of the mucus cells are smaller than those of the _ other cell types (Fig. За). A strong muscle layer, connective tissue cells and nerves with different neurosecretory vesicles can be found subtending the epithe- lium (Fig. 2a, 40, 42). In longitudinal section, the muscle filaments are all roughly parallel, while in transverse section there is a quasi- lattice of thick and thin filaments (Fig. 40). In the haemolymph space some macrophages can be observed. They are characterized by a large nucleus, small Golgi apparatus and a few small vesicles of various electron-density (Fig. 2a). Crop: Apart from a few mucus (Type lll) and small electron-lucent cells (Type IV), the cylindrical epithelium of the crop is dominated by a single cell type, resembling the storage DIGESTIVE TRACT OF DEROCERAS 143 (1) Cb) CROP (a) OESOPHAGUS Il I ШМ (d) MIDGUT-GLAND м Er N vvı Vi FIG. 1. Diagram of the digestive tract of Deroceras reticulatum illustrating the cells investigated in the present study. 1a. Oesophagus: Storage cell (I), secretory cell of an eccrine type (Il), secretory се! of a holocrine type, called mucus cell (111), and small electron-lucent cell (IV) 1b. Crop: Storage cell 1c. Stomach and adjacent intestine: Storage (I) and mucus cell (111) 1d. Mid-gut gland: Digestive cell (V), crypt cell (VI), and excretory cell (VII) cell (Type |) of the oesophagus (Fig. 1b). Only Stomach and adjacent intestine: Half of in regions of the crop adjacent to the stomach the stomach epithelium is made up by cells do these cells bear cilia. resembling the storage cells of the oesopha- A small muscle layer with associated con- gus with respect to their ultrastructural organ- nective tissue and nerves underlies the epi- isation and storage products (Fig. 1c). The thelium. cells always bear microvilli and cilia (cf. 144 + = 2a) CONTROL (b) CARBAMATE In Ñ NU \ = ACT \ (arg O: A | Re 5 = ee E . * N aan QUA po... SET storage cell 7 ZX Y Ja RR т 4 vi *E TRIEBSKORN a | 2 N FIG. 2. Reconstruction of an unciliated or ciliated storage cell (2a) and its habit after carbamate (2b) and metaldehyde (2c) intoxication Walker, 1972). In the stomach crypts, the cilia are longer and more numerous (cf. Haffner, 1924). The rest of the epithelium is made up by mucus cells (Type Ill). In the adjacent in- testine, half of the cells are mucus cells (Type 111), and only a quarter are storage cells (Type |. The other quarter of the cells are secretory (Type Il). An underlying muscle layer is well developed. It can be compared with that of the oesophagus (Fig. 40). Many nerve fibres can be detected. Mid-gut gland: The epithelium of the mid- gut gland is arranged in tubules that are bound together by a meshwork of connective tissue. An underlying muscle layer is lacking. Three cell types can be distinguished (Fig. 1d, 4a): Type V: The columnar digestive cells, highly vacuolized absorptive cells, that domi- nate the epithelium. The vacuoles vary in size and are generally largest towards the basal regions of the cells. Pinocytotic vesicles de- velop along the apical plasma membrane, where endocytotic channels can also be found. The absorptive area is increased by numerous microvilli. The digestive cell cyto- plasm contains a little granular endoplasmic reticulum, a few mitochondria and an occa- sional small Golgi apparatus. Lipid and gly- cogen storage can be found. The nuclei of these cells are basally located. Type VI: The crypt cells are conical in shape with broad bases abutting on to the haemolymph space. Serving secretory func- tions, they are characterized by a large amount of granular endoplasmic reticulum (Fig. 22), a great number of Golgi stacks and . secretory vesicles in the perinuclear cyto- plasm. The nuclei are basally situated, pos- sess a large nucleolus and have scattered patches of heterochromatin. Mitochondria are located near the apical and the basal surfaces of the cells. Lipid and carbohydrate storage, as well as membrane-bound spherites are present (Fig. 4a). The microvilli are longer than those of the digestive cells, and the basal labyrinth is well developed. Type VII: The goblet-like excretory cells are characterized by large and small vacuoles containing electron-dense material (Fig. 27). The membrane of the large vacuole shows numerous infoldings. In the cytoplasm a small Golgi apparatus, a small amount of smooth and granular endoplasmic reticulum and lipid, and a few mitochondria can be found. The DIGESTIVE TRACT OF DEROCERAS 145 за) CONTROL b ) CARBAMATE Ir { ke ON Mo ь bm >> fully differentiated mucus cell young mucus cell € )METALDEHYDE FIG. 3. Reconstruction of a young and a fully differentiated mucus cell in control animals (3a), after car- bamate (3b), and after metaldehyde intoxication. microvilli ofthese cells are as long as those of the crypt cells. To compare the different theories concern- ing the genealogy of these cells and the dif- ferent nomenclatures, see David & Götze (1963) and Walker (1970). Histopathological alterations (Figs. 2, 3, 4) Generally speaking, the cytological reac- tions in the digestive tract originate in isolated cells and spread over the epithelium during the following hours. Sixteen hours after inges- tion of the molluscicides, a high percentage of the cells are significantly damaged. The reactions observed after five and 16 hours generally resemble those after one hour, but they are more intense. Reactions that appear in the anterior part of the digestive tract immediately after the mol- luscicide treatment became apparent in cells of the posterior part with a time lapse corre- sponding to the transport rate of toxic food- stuff. Sixteen hours after carbamate ingestion, a lot of cells have been extruded from the epi- thelium. Reactions of the basal and apical cell surfaces MESUROL: Immediately after the applica- tion of Mesurol, the basal surfaces of storage and secretory cells (Type | and Il) are slightly stretched (Comp. Figs. 5 and 6). After five and 16 hours, the cells exhibit considerably extended basal cell extensions (Fig. 7) that sometimes contact nerve or muscle cells (Fig. 8). In the mid-gut gland the basal cell exten- sions are less distinct than in the alimentary tract. However, the basal labyrinth of crypt cells is distended, and the intercellular spaces are enlarged (Fig. 35). Comparable to the reactions of the cell bases, the apical surfaces of the cells react very quickly with a reduction of microvilli and cytoplasmic protrusions in the anterior, and after five or 16 hours in the posterior parts of the digestive tract (Figs. 10, 11, 12). An intensified vacuolization in the digestive cells often leads to a breakdown of the apical membrane. METALDEHYDE: After intoxication with metaldehyde, basal cell extensions are lack- ing; the basement membrane is thickened and becomes more electron-dense (Fig. 9). Protrusions of the apical cytoplasm and re- duction of microvilli can occasionally be found. After intoxication with carbamate and met- aldehyde, the shape of all cell types becomes more irregular (Figs. 2, 3, 4). Reactions of the cytoplasm MESUROL: After carbamate intoxication, the cytoplasm of storage and secretory cells appears slightly condensed (Fig. 7) or elec- 146 TRIEBSKORN __ CARBAMATE digestive cell crypt cell FIG. 4. Reconstruction of a digestive and a crypt cell of the mid-gut gland (4a) and its variable habit after carbamate (4b) and metaldehyde (4c) ingestion. tron-lucent (Fig. 13). In the digestive cells of the mid-gut gland, it is either extremely elec- tron-lucent, or totally electron-dense, depend- ing on the degree of vacuolization. Electron- dense cytoplasmic areas often surround the nuclei. METALDEHYDE: In mucus cells the cyto- plasm is displaced by the enlarged mucus vacuoles (Fig. 33). In all cell types it appears less electron-dense. Reactions of the nuclei MESUROL: One hour after intoxication the nuclei are severely damaged. The karyoplasm becomes less electron- dense (Fig. 13, 14, 15), lipid droplets can be detected in it (Fig. 15), the nucleoli are irreg- . ularly deformed (Fig. 16), and the amount of heterochromatin is reduced. In some cases, the karyoplasm appears totally condensed (Fig. 17), or, especially in crop cells, small vesicles can be found in it (Fig. 16). Mitotic processes are evident. However, even after 16 hours, there are still some unafflicted nu- clei next to totally damaged ones (Fig. 17), emphasizing the heterogeneity in cellular re- action. METALDEHYDE: After metaldehyde in- gestion, damage to the nuclei is less intense than after carbamate application. The karyo- plasm becomes less electron-dense, and in a few cases it bears lipid droplets (comp. Fig. 14). Especially in the crypt cells ofthe mid-gut gland, the amount of heterochromatin is re- duced. Reactions of the mitochondria MESUROL: After carbamate intoxication, mitochondrial effects originate in the oesoph- agus and crop cells from the cell apex, while in the posterior parts of the digestive tract mi- tochondria located in the basal cytoplasm are afflicted earlier. Especially in the stomach and the digestive gland, electron-dense granules different from the common intramitochondrial granules can be found in mitochondria, located in mem- brane-bound compartiments (Fig. 18). Fur- thermore, the organelles are heavily inflated and their cristae are reduced (Fig. 19). METALDEHYDE: After metaldehyde in- toxication, the mitochondria are less afflicted than after carbamate ingestion. The common intra-mitochondrial granules are often en- larged (Fig. 20), and only in a few cases the organelles are swollen. Reactions of the endoplasmic reticulum MESUROL: After Mesurol application, the smooth and granular endoplasmic reticulum proliferates in basal regions of storage, diges- tive and crypt cells. In most cases, the smooth endoplasmic reticulum is heavily distended (Fig. 21). Degranulation of granular endoplas- mic reticulum can be observed in basal re- DIGESTIVE TRACT OF DEROCERAS 147 FIG. 5. Oesophagus, control: Section through the basal part of the oesophagus epithelium showing a mucus (тис), storage (sc) and small light cell (sic). There are no infoldings of the cell basis (arrows). FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. 6. Oesophagus, Mesurol, 1 В: Slight basal extensions (arrows). 7. Oesophagus, Mesurol, 5 hs: Strong basal extensions (arrows). 8. Oesophagus, Mesurol, 1 h: Contact of a basal cell extension (be) to a nerve cell (nc,arrow). 9. Crop, metaldehyde, 5 hs: Thickening of the basal membrane (bm). 10. Crop, control: Apex of a storage cell, showing regularly orientated microvilli (mv). 11. Oesophagus, Mesurol, 1 h, storage cell: Slight cytoplasm extrusions (ce, arrows). 12. Oesophagus, Mesurol, 1 h, storage cell: Intensified cytoplasm extrusions (ce, arrows). 13. Oesophagus, Mesurol, 16 hs, secretory cell: Electron-lucent cytoplasm (cyt) and nucleus (n) with the heterochromatin reduced (arrows). 148 TRIEBSKORN FIG. 14. Oesophagus, Mesurol, 5 hs, storage cell: Nucleus (n) with a totally dissolved karyoplasm. FIG. 15. Stomach, Mesurol, 5 hs: Nuclei with lipid inclusions (li) in an electron-light karyoplasm. FIG. 16. Crop, Mesurol, 1 h: Nucleus with an irregularly formed nucleolus (nu) and small vesicles (v) in the karyoplasm (inset, x 6). FIG. 17. Crop, Mesurol, 16 hs: Totally damaged nucleus next to an unafflicted one in the adjacent crop cell. FIG. 18. Mid-gut gland, Mesurol, 16 hs, crypt cell: Mitochondrion (m) with inclusions in membrane-bound areas (arrows); common intramitochondrial granules (gm) are visible. FIG. 19. Oesophagus, Mesurol, 1 h, secretory cell: Destruction of cristae in mitochondria (arrows). FIG. 20. Stomach, metaldehyde, 5 hs, storage cell: Mitochondrion with enlarged intramitochondrial granules (arrows). FIG. 21. Intestine, Mesurol, 5 hs, storage cell: Dilation of smooth endoplasmic reticulum (ser) in the basal parts of the cell. FIG. 22. Mid-gut gland, control, crypt cell: Cisternae of the granular endoplasmic reticulum (ger). DIGESTIVE TRACT OF DEROCERAS 149 gions of the crypt cells (comp. Figs. 22 and 23). In mucus cells the granular endoplasmic re- ticulum is dilated and disorientated. After sev- eral hours, the membranes become frag- mented. METALDEHYDE: The damage to the granular endoplasmic reticulum in mucus cells is more intense after metaldehyde than after carbamate intoxication. The cisterna are heavily dilated, and the membranes are disarranged, ruptured and sometimes coiled to form myeline figures (comp. Figs. 25 and 26). In the crypt and excretory cells of the mid- gut gland, the granular endoplasmic reticulum disintegrates into short cisternae with frag- mented membranes, frequently devoid of ri- bosomes (Fig. 28). The cisternae of the en- doplasmic reticulum often form fingerprint-like structures (Fig. 24). In many instances, the membranes are ruptured. Reactions of the Golgi apparatus MESUROL: In the oesophagus, the Golgi complexes of the secretory cells (Type Il) are heavily damaged. Especially the trans-face cisternae are either compressed or highly in- flated (comp. Figs. 29 and 30). Associated with this is a reduction in the number of secre- tory vesicles. In the mucus cells, the cisternae of the Golgi apparatus are strongly dilated (Fig. 31), and the regular arrangement of the Golgi stacks is often lost. METALDEHYDE: Except for the mucus cells, the reaction of the Golgi apparatus is less intense after metaldehyde than after car- bamate ingestion. The trans-faces of the cis- ternae are slightly dilated. In the mucus cells, the Golgi cisternae are swollen, often the membranes are arranged as concentric whorls (Fig. 32), and the mucus containing vacuoles are enlarged (Fig. 33). Alteration of storage products MESUROL: After carbamate ingestion, compact areas containing glycogen or galac- togen can be found between lipid droplets, especially in central and basal parts of diges- tive cells and in crypt cells of the mid-gut gland (Fig. 35). METALDEHYDE: In storage, secretory, di- gestive, crypt and excretory cells, the amounts of lipid and glycogen are reduced after metaldehyde poisoning (comp. Figs. 34 and 36). This reduction is related to the pres- ence of vesicles containing electron-dense material with a typical lamellar fine-structure (Fig. 37). Furthermore, an increased number of peroxisome-like structures appears. Reaction of the cytoskeleton MESUROL: After Mesurol intoxication, no reaction of the cytoskeleton is visible. METALDEHYDE: In the center of storage and secretory cells (Type | and Il), condensed actin-like microfilaments appear (Figs. 38, 39). Reactions of the underlying muscle, connective and nerve tissues MESUROL: After the application of the carbamate molluscicide, the muscle tissue is fragmented, and the regular arrangement of the muscle filaments is disturbed (comp. Figs. 40 and 41). Granules similar to peroxisomes (with regard to their size and their electron- density) appear in connective tissue cells showing intensive contact to smooth muscle and nerve cells, as well as in nerve cells themselves (Figs. 42, 43). METALDEHYDE: After application of me- taldehyde, no reactions of muscle, nerve and connective tissue could be found. Reactions of the macrophages MESUROL: After ingestion of Mesurol, the number of macrophages in the haemolymph space increases. In many cases, mitotic pro- cesses can be observed (Fig. 44). Particularly 16 hours after intoxication, many of these cells penetrate the epithelium (Fig. 45). Other macrophages contain membrane fragments incorporated into vacuoles (Fig. 46). METALDEHYDE: Reactions of the macro- phages are lacking. DISCUSSION The present study reveals the impact of the carbamate compound Mesurol and of metal- 150 TRIEBSKORN FIG. 23. Mid-gut gland, Mesurol, 1 h, crypt cell: Degranulation of granular ER in the basal part of the cell (arrows). FIG. 24. Mid-gut gland, metaldehyde, 5 hs, crypt cell: Granular ER (ger) forming fingerprint-like structures. FIG. 25. Oesophagus, control, mucus cell: Elaborate Golgi system (ga), granular ER (ger) and mucus vacuoles (muv) in a regular arrangement. FIG. 26. Oesophagus, metaldehyde, 5 hs, mucus cell: Dilated, electron-lucent cisterae of the granular ER and Golgi membranes (ga) forming concentric circles in a cellular disarrangement; nucleus (n) with an electron-lucent caryoplasm. FIG. 27. Mid-gut gland, control, Excretory cell: excretory cell with excretory granule (eg). FIG. 28. Mid-gut gland, Mesurol, 5 hs, crypt cell: Short, fragmentary cisternae of the granular ER (ger) frequently devoid of ribosomes. FIG. 29. Oesophagus, control, secretory cell: Trans- and cis-face of the Golgi apparatus (ga) can clearly be distinguished. FIG. 30. Oesophagus, Mesurol, 1 h, secretory cell: Heavily inflated cisternae of a Golgi apparatus (ga). DIGESTIVE TRACT OF DEROCERAS 151 FIG. 31. Stomach, Mesurol, 5 hs, mucus cell: Golgi apparatus (ga) with dilated cisternae (arrows). FIG. 32. Oesophagus, metaldehyde, 5 hs, mucus cell: Membranes of the Golgi apparatus (ga) are arranged as concentric whorls surrounding Golgi vesicles. FIG. 33. Stomach, metaldehyde, 5 hs: General view ofthe mucus cells after metaldehyde application; dilated cisternae of the Golgi apparatus and the granular ER, large mucus vacuoles (muv) and nuclei (n) with an electron-lucent karyoplasm. FIG. 34. Oesophagus, control, storage cell: High amount of stored lipid (li) and glycogen or galactogen (gl). FIG. 35. Mid-gut gland, Mesurol, 5 hs, digestive cell: Condensation of glycogen (gl) and dilation of the SER and the basal labyrinth (bl). FIG. 36. Oesophagus, metaldehyde, 5 hs, storage cell: Lipid and carbohydrate reduction; electron-dense vesicles (ev) and ER membranes forming a fingerprint-like structure (arrow). FIG. 37. Oesophagus, metaldehyde, 5 hs, storage cell: Electron-dense vesicles (ev) characterized by a typical lamellar fine-structure (inset, x 4) and by peroxisome-like organelles (p) in the center of the cell. FIG. 38. Crop, metaldehyde, 5 hs: Reduction of storage products and aggregation of actin-like filaments (arrows). FIG. 39. Crop, metaldehyde, 5 hs: Actin-like filaments (af) in the center of the enterocytes. 152 TRIEBSKORN FIG. 40. Oesophagus, control: Muscle cell (mc) with regularly orientated muscle fibres. FIG. 41. Oesophagus, Mesurol, 5 hs: Fragmentation of muscle tissue in isolated portions and irregular orientation of muscle fibres. Intense contact of nerve (nc) and muscle cell (mc). FIG. 42. Oesophagus, Mesurol, 1 h: Nerve (nc) and connective tissue cells (cc) containing electron-dense, peroxisome-like structures. FIG. 43. Oesophagus, Mesurol, 5 hs: Nerve with peroxisome-like structures (р). FIG. 44. Oesophagus, Mesurol, 5 hs: Mitosis taking place in a macrophage (ma). FIG. 45. Oesophagus, Mesurol, 16 hs: Macrophage bearing membrane fragments in vacuoles (arrows). FIG. 46. Oesophagus, Mesurol, 1 h: Two macrophages that penetrate the epithelium. DIGESTIVE TRACT OF DEROCERAS 153 dehyde on the ultrastructure of the digestive tract of Deroceras reticulatum. In addition to the results of Tegelsstrom & Wahren (1972), Godan (1979) and Pessah & Sokolove (1983), who attributed the molluscicidal ef- fects to influences on cholinesterase activity and water regulation, it can clearly be dem- onstrated that both chemicals interact with several different types of enterocytes. As evident by the present cytological find- ings, the carbamate compound Mesurol is ab- sorbed immediately after ingestion in the an- terior parts of the digestive tract, i.e. in the oesophagus and the crop. The rapid reac- tions in these two regions and the quick and intense reaction of the whole animal one hour after feeding support the findings of Fretter (1952), Walker (1972) and Horst et al. (1986), who describe the high absorptive activity of the crop using radioactive labelling and bio- chemical methods. With regard to the time lapse resulting from the passage of food through the intestinal tract, the cellular re- sponses after one hour in the anterior parts can be compared with those in the posterior parts of the digestive system after five hours. Analysis of cellular responses to metaldehyde and carbamate poisoning after five hours al- lows three types of reaction to be distin- guished: carbamate-specific reactions, metal- dehyde-specific reactions, and cell responses that appear in both experiments but with dif- ferent intensity. Reactions such as cytoplasm condensa- tion, cytoplasmic protrusions also called “surface blebs” (Whyllie, 1981; Réz, 1986), reduction of microvilli, mitochondrial swelling (Goyer & Rhyne, 1975; Triebskorn, 1988) and dilation of Golgi cisterna (Triebskorn, 1988), endoplasmic reticulum and intercellular spaces (Smuckler & Arcasoy, 1969), as well as ER-membrane proliferation or destruction (Moore, 1979, 1985; Nott & Moore, 1987) re- semble those described in bivalves and ver- tebrates as cellular stress symptoms after in- toxication with different xenobiotics. Likewise, the degranulation of the granular ER and the formation of membrane whorls or myelin-like membranes by ER are discussed as general changes of the cell in response to toxicants (Réz, 1986). Most of these reactions are at- tributed to membrane destabilization and in- creased membrane permeability to ions un- der the influence of toxicants, followed by osmotic effects and finally cell death (Sparks, 1972). Swelling of mitochondria is suggested to be the result of an increased Ca?* influx (Packer et al., 1967; Smuckler & Arcasoy, 1969). Bayne et al. (1985), Moore (1985) and Nott & Moore (1987) relate the sER proliferation to an increase of SER-bound detoxification en- zymes, such as the NADPH-neotetrazolium- reductase and many others. In the digestive tract of Deroceras reticula- tum, such unspecific reactions are more in- tense after carbamate than after metaldehyde treatment except for the mucus cells of oe- sophagus, stomach and intestine. This might arise from the fact that the amount of metal- dehyde taken up by the animals is supposed to be closer to the sublethal dose than that of carbamate. Therefore, after Mesurol intoxica- tion, many more cellular reactions associated with cell death are involved. However, the comparison of reactions to different mollusci- cides in several regions of the digestive tract, as well as in several cell types at three times allows reactions of general nature to be dis- tinguished from specific ones. Thus, for ex- ample, in mucus cells the destruction of Golgi cisternae, rER and mitochondria is more prominent after metaldehyde than after car- bamate ingestion. This severe impact of met- aldehyde on the mucus producing cells cor- relates well with the known influence of this molluscicide on water regulation. Metalde- hyde enhances the extrusion of available mu- cus immediately after intoxication. This mu- cus might serve to dilute the toxin but may also have the capacity to detoxify it (Trieb- skorn, 1988). It passes the digestive tract and is voided quickly due to the intensified mucus extrusion of the whole animal. Furthermore, the replacement of the necessary mucus is blocked by destruction of the cellular secre- tory apparatus, especially in immature cells. If the resulting loss of liquid cannot be compen- sated, the animal will desiccate. Therefore, the effects of metaldehyde are reversible in a humid climate. These considerations are in line with other investigations studying the advantages of car- bamates compared with metaldehyde using LD tests (Riemschneider & Heckel, 1979; Prystupa et al., 1987). They support the find- ings of Getzin & Cole (1964), who postulate the effect of metaldehyde to be the result of water loss by stimulation of mucus secretion. Furthermore, metaldehyde poisoning re- duces cellular lipids, increases the number of electron-dense vesicles and peroxisome-like particles, and leads to a thickening of the basement membrane and the condensation 154 TRIEBSKORN of actin-like filaments in the cytoplasm. Until now, there are no targets known for the attack of toxins in the cytoskeletal system. Nor is there any intelligible explanation for the thick- ening of the basement membrane. With regard to lipid reduction, my own en- zyme-histochemical studies have shown that catalase activity can be found in the periphery of lipid droplets after molluscicide intoxication (Triebskorn, in prep.). One might speculate that the observed lipid reduction is correlated with lipid peroxidation (cf. Tappel, 1975). To reinforce this idea, the presence of detoxifica- tion products resulting from such reactions as well as the nature of the electron-dense ves- icles and the peroxisome-like structures should be investigated. Beyond this, the re- action of macrophages and connective tissue cells after intoxication with Mesurol could be of interest. While the present study demon- strates an increased number of peroxisome- like structures in connective tissue cells after Mesurol intoxication, Sminia (1972) was able to demonstrate peroxidase activity in hae- molymph cells, localized in similar per- oxisome-like vesicles. In addition, my own light-microscope investigations reveal an in- tensified catalase activity in the connective tissue underlining the epithelium of the diges- tive tract and in the haemolymph, where mac- rophages can be found (Triebskorn, in prep.). Because peroxidative reactions are known to be involved in detoxification (Belding et al., 1970; Recknagel, 1967), | assume that sim- ilar processes are of importance in the diges- tive tract of slugs after molluscicide intoxica- tion. Whereas they might be found after metaldehyde treatment in the enterocytes themselves, carbamate poisoning leads to a disturbance of essential functions of these cells so quickly that detoxification processes cannot be established in them in time. This deficiency might be compensated by mac- rophage activity. The function of these cells in detoxification is also verified by the results of Moore (1979). He could demonstrate the ac- tivation of MFO-enzymes in the haemolymph cells of Mytilus edulis after polycyclic hydro- carbon poisoning. Furthermore, the haemo- cytes are known to be able to penetrate the gut epithelium and to phagocytise decaying cells (Sminia, 1972). The macrophage reaction, nucleic damage and a changed glycogen metabolism appear one hour after the ingestion of the carbamate. The Mesurol attack on the nucleus seems to be the most important effect of this chemical and accounts for its better molluscicidal activ- ity compared with metaldehyde. While kary- olysis is often described as a late reaction to intoxication in vertebrates and invertebrates (Bayne et al., 1985), the reaction of nuclei in the present study does not seem to be an ultimate one revealing cell death, but a pri- mary cell response that leads to cell death. Since, in most cells with damaged nuclei, other cell death symptoms are lacking, the heterochromatin disorganization and in- crease in mitotic activity seem to reflect a central process in intoxication. The damage to the nuclei could explain the reinforcement of other cellular responses, such as the dis- turbances in glycogen metabolism or the de- struction of Golgi apparatus, already de- scribed by Flickinger (1971). In contrast to these reactions, the formation of basal cell extensions requires several hours. This is probably due to the inhibition of cholinesterase activity by carbamates. The blockade of the esterase center of the en- zyme (Wegler, 1970) interrupts nerve stimuli conduction, leading to uncontrolled muscle contraction and finally to muscle atony. Un- controlled contractions in the muscle layer that underlies the gut epithelium are respon- sible for the basal cell deformation. In conclusion, the present results suggest that the cells might respond to environmental stress in different ways. Lipid mobilization in storage cells, for example, only takes place after intoxication with less effective mollusci- cides, such as metaldehyde. Carbamate in- gestion stimulates the activity of the macro- phages. Furthermore, peroxidative reactions have been suggested to be the biochemical pathway of detoxification of carbamate and ‚ metaldehyde. According to this opinion, the detoxification processes in molluscs resemble those described for insects by Wegler (1970). The present electron microscope study was able to extend former observations on whole animal behavior following intoxication. Sug- gestions about cellular mechanisms induced by different molluscicides are developed. However, other techniques, such as enzyme histochemistry, biochemistry and autoradiog- raphy, are necessary to further specify these results and to give more detailed information about the function of the structures described. ACNOWLEDGEMENTS This work was partly supported by the Ger- man Research Council (DFG Sto 75/9; Ja 407/ DIGESTIVE TRACT OF DEROCERAS 155 1-1). Personal thanks go to Günter Vogt, Thomas Braunbeck and Ulrich Bielefeld for the revision of the paper and for help with the English version. Thanks are also due to Dr. Janssen, to Prof. Storch and to Dr. Künast (BASF), who encouraged the present investi- gation and provided laboratory facilities and chemicals. LITERATURE CITED BAKHTAWAR, P. M. & V. K. 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Revised Ms. accepted 20 June 1989 ABBREVIATIONS actin-like filament basal extension basal labyrinth basal membrane cilia connective tissue cell cytoplasmic extrusion calcium granule cytoplasm digestive vacuole endocytotic channel excretory granule endocytotic vesicle electron-dense vesicle golgi apparatus granular endoplasmic reticulum glycogen intramitochondrial granule intramitochondrial vesicle lipid lysosome macrophage muscle cell membrane fragments mitochondria mitosis mucus cell mucus vacuole microvilli nucleus nerve cell nucleolus neurosecretory vesicle peroxisome-like vesicle storage cell small electron-lucent cell smooth endoplasmic reticulum secretory vesicle MALACOLOGIA, 1989, 31(1): 157-173 RETRACTION/EXTENSION AND MEASUREMENT ERROR IN A LAND SNAIL: EFFECTS ON SYSTEMATIC CHARACTERS Kenneth С. Emberton Department of Malacology, Academy of Natural Sciences, 19th and the Parkway, Philadelphia, Pennsylvania, U.S.A. 19103 ABSTRACT Multivariate analyses were performed on replicated measurements from a collection of 56 preserved Ningbingia dentiens Solem, 1985 (Gastropoda: Stylommatophora: Camaenidae), that ranged from full extension to full retraction. The positions of body landmarks during retraction/ extension vary complexly such that the only reliable indicator is the position of the foot tip relative to the remaining body wall. Shell size is no predictor of retraction/extension state. The nerve ring dilates, then compresses, as the buccal mass passes through it. From fully extended, to partially retracted, to fully retracted specimens, vagina length decreases 25%, then increases 10%; spermatheca length remains constant, then decreases 20%; and penis length decreases 15%, then increases 5%. Counting shell whorls (mean 5.0) to the nearest 0.1 whorl was exactly as precise as measuring shell height (mean = 8.4 mm) to the nearest 0.1 mm; both were 1/7 as precise as measuring shell diameter (mean = 17.1 mm) to the nearest 0.1 mm. Distances among body landmarks within the shell had measurement errors 30 x to 340 x greater inan for shell diam- eter. Measurement error was about 10% of total variance for vagina length, 20% for sperma- theca length, and 30% for penis length. The effects of measurement error and retraction/ extension equaled or surpassed individual variation for all three of these measurements. Key words: Gastropoda, Pulmonata, Camaenidae, Ningbingia dentiens, retraction, measure- ment error, anatomy, systematics. INTRODUCTION When a pulmonate land snail retracts into its shell, it invaginates the anterior part of the body, during which air is vented from the mantle cavity and blood redistributes among sinuses of the hemocoel (Jones, 1975). This process alters the relative positions, lengths, and shapes of the snail’s organs. Since no fully reliable method has yet been found for always killing and fixing pulmonate land snails in an extended state (the success rate of the standard procedure of drowning in water or in a weak solution of chloryl hydrate or nicotine varies widely, depending on the taxonomic group and on field conditions), land-snail sys- tematists must often compare specimens dif- fering widely in their degree of body retraction/ extension. The effect of retraction/extension on body organs is poorly understood. Studies on body retraction in pulmonates (reviewed by Jones, 1975) have so far been physiological in ap- proach, with little information on anatomical variation relevant to systematists. The most relevant study to date (Dale, 1974) noted only 157 that “the genital and digestive organs in the retracted snail are located [between] the man- tle cavity floor [and the retracted head-foot],” resulting in an unspecified degree of distor- tion of these organs. The role of measurement error in quantita- tively assessing both shell and soft-parts has never been examined in great detail. For ex- ample, various gastropod systematists mea- sure whorl-count to the nearest 1/4-whorl, 1/8-whorl, 1/10-whorl, and 1/16-whorl, rarely with a published demonstration that that is the limit of achievable accuracy. Soft-part mea- surements, primarily of the lower reproductive tracts, are frequently presented in the taxo- nomic literature, sometimes with caveats about measurement error, but seldom with explicit assessments of its effect. Furthermore, when an investigator must choose which specimens to dissect from a preserved lot in which all are retracted within the shell, it would help to know whether the depth of retraction can be predicted from ei- ther shell size or the positions of body land- marks visible through the shell. The purposes of this paper are, for a single 158 EMBERTON collection from a panmictic population of a pulmonate land snail, to (1) investigate the relative positions of body landmarks through- out a range of retraction/extension states; (2) test whether shell size is any predictor of re- traction/extension state; (3) qualitatively and quantitatively assess the effects of retraction/ extension on organ systems of systematic value; (4) compare the precisions of shell and soft-parts measurements; and (5) determine the relative contributions of retraction/exten- sion, individual variation, and measurement error to the total variance in the lengths of the vagina, spermatheca, and penis. MATERIALS AND METHODS This study made use of a single collection of Ninbingia dentiens Solem, 1985, a camaenid snail endemic to the northern Ningbing Ranges, north of Kununurra, the Kimberley, Western Australia. Sixty live, paratopotypic adults (Western Australian Museum 14.84 and Field Museum of Natural History 205270) had been collected from a small pocket of ta- lus on a limestone dome that was shaded by a 2.5-meter boulder by A. Solem, L. Price, and B. Duckworth on 15 June 1980. The total area of the colony was much less than one cubic meter, and other colonies were sepa- rated by at least 50 meters of barren rock. Because of these conditions, the specimens almost surely belonged to a single panmictic population. The collection was made about two months into the dry season. All specimens therefore were in a state of estivation when collected. All were at least third-year adults, as evi- denced by their full-sized albumen glands (see Solem & Christensen, 1984). After drowning overnight in two or three wa- ter-filled, small jars, t0 each of which a few crystals of chloryl hydrate had been added, the specimens were fixed the next morning in 95% ethanol. On reaching Chicago two months later, they were transfered to 70% ethanol. The preserved specimens exhibited a complete range of retraction states, from fully extended to tightly retracted. They af- forded the best opportunity | have yet encoun- tered to investigate variation in body retraction/ extension as it occurs in typical alcohol- preserved museum specimens. From the 56 intact specimens—three had previously been dissected (Solem, 1985), and the shell of one was accidently broken—I measured shell height and diameter to the nearest tenth of a millimeter, and whorl count to the nearest twentieth of a whorl. Also to the nearest twentieth of a whorl, | measured the location, as seen from the ventral side, of the shell's basal lip, the mantle color, the tip of the foot, the auricular-ventricular junction (a-v junction) of the heart, and the base of the om- matophore (upper, eye-bearing antenna). The heart's position was occasionally difficult to locate through the shell; changing the an- gle of illumination helped to pinpoint it. The mantle collar and the tip of the foot of re- tracted snails were clearly visible through the shell. The base of the ommatophore of re- tracted snails, however, was impossible to ac- curately locate, so instead | measured the most apical point of the invaginated left om- matophore, which was visible as a black tube through the ventral shell. From the dorsal sur- face of the shell | also measured the position of the apex of the liver (posterior digestive gland), to the nearest tenth of a whorl. This was sometimes obscured by opacity of the shell apex or by the presence of denatured fluid in the empty apical whorls, but could be detected by moving the narrow-beam illumi- nator, particularly by reflecting the light off the table surface into the umbilicus of the shell. All whorl-increment measurements were taken under magnification over a subdivided circle; shell height and diameter were taken manually with dial calipers. From these nine soft-part measurements, | calculated the following distances, all ex- pressed to the nearest twentieth of a whorl: (1) MANTLP, from the mantle collar to the shell’s basal Ир; (2) FOOTIP, from the mantle collar to the tip of the foot; (3) ANTENN, from the base of the everted left ommatophore or the ante- riad extent of the inverted left ommatophore to the heart a-v junction; (4) PALCAV, from the mantle collar to the heart a-v junction (this was used as an index of the length of the pallial cavity, the actual apex of which was not reli- ably discernable); (5) VICMAS, an index of the length of the visceral mass, from the heart a-v junction to the apex of the liver; and (6) EMPAPX, the empty apex of the shell, from the zero-whorl apical notch to the apex of the liver. To determine their precision, | took all mea- surements and performed all calculations three separate times. For each of the three shell measurements and the six calculated soft-part variables, | calculated two different indices of precision. The first was a mean co- LAND-SNAIL RETRACTION/EXTENSION 159 TABLE 1. Loadings of principal components extracted from soft-part measurements associated with retraction/ extension. See text and Fig. 1 for explanation of variables. Variable PC1 MANTLIP — 0.38 FOOTIP 0.30 ANTENN 0.46 PALCAV 0.31 VICMAS —0.47 EMPAPX 0.49 % Variance 44% efficient of variation. For each specimen, | cal- culated the coefficient of variation (standard deviation divided by the mean) of its three replicate measurements, and averaged these coefficients over all specimens. The second index was the percentage of specimens with a coefficient of variation of zero, i.e. with iden- tical replicate measurements. For the shell variables only, | performed а third analysis of precision: making pairwise comparisons among the three sets of measurements, | cat- egorized all deviations as to size, then aver- aged the percentage of specimens falling within each category of deviation. Principal components analysis was used to explore the interrelationships among the soft- part distances during retraction/extension. To determine the influence of shell size and shape on this process, | computed the canon- ical correlations between the set of shell mea- surements and the set of soft-part distances. For these analyses, | used only the third set of measurements rather than the average of all three sets because of my belief that the ac- curacy of soft-part measurements increased with practice. After measuring the shells and body land- marks, | cracked and removed the shells, dis- sected off the mantle collar and diaphragm (= floor of the mantle cavity) from each spec- imen, sewed on an identification tag, then ranked the specimens from 1 to 57 according to how much of the head-foot was showing beneath the folded body wall—from all of the head and foot to just the tip of the foot. | called this variable the retraction/extension rank (RETRAN). | calculated non-parametric cor- relation ceoffficients ‘between RETRAN (which was non-normally distributed) and each of the first four principal components of soft-part distances. | took five snails from each of four stages of the head-foot retraction series: “stage a,” PC2 PC3 PC4 —0.09 0.47 0.78 0.65 0.30 0.01 0.46 —0.05 0.33 —0.20 — 0.67 0.51 0.43 — 0.32 — 0.06 — 0.36 0.35 —0.09 24% 19% 9% complete extension, ranks 1—5; “stage b,” head invagination, ranks 20-24; “stage с,” half-way foot retraction, ranks 35-39; and “stage а,” full foot retraction, ranks 53-57. From each of these 20 snails | took the fol- lowing genital measurements: (1) vaginal length, from its beginning where the free ovi- duct and the spermatheca unite in a V-junc- tion to where it joins with the penis in a V- junction (the penioviducal angle) to form the atrium; (2) spermathecal length, from the free oviduct-spermathecal junction to its tip; (3) penis-plus-sheath length, from the peniovidu- cal angle to the insertion of the penial retrac- tor muscle; and (4) penis-minus-sheath length, from the penioviducal angle to the basal attachment of the sheath as best judged without dissection. After taking these measurements from the 20 snails and return- ing them to their vials, | repeated this mea- surement process twice. For each of the four genital measurements, | used two-way nested analysis of variance (ANOVA) to test for significant differences among retraction/ extension stages and among snails within a stage; and to partition the variance among re- traction/extension stage, individual variation, and measurement error. | next slit and pinned open the uneverted penial tube and sheath of each of the 20 snails, and took five measurements of penial sculpture. These were: (1) left pilaster mid- width, (2) right pilaster mid-width, (3) number of wall ridges at the apical penis, (4) number of wall ridges at the mid-penis, and (5) central wall ridge mid-width. Means and standard de- viations for each extension/retraction stage were calculated. From each extension/retraction stage (a- d), | chose one well-dissected representative specimen (those with RETRAN ranks 1, 24, 38, and 54) for detailed dissection and illus- tration. 160 EMBERTON RESULTS Four principal components accounted for 96% of the variation in distances among body landmarks during retraction/extension. The structures of tnese components are listed in Table 1 and are presented diagrammatically in Fig. 1, in which the relative contribution of each distance to each principal component is expressed as the width of its line, and the direction of its contribution is indicated by one or more arrowheads. The first two principal components (PC 1 and PC 2), accounting for 44% and 24% of the total variance, involve simultaneous eversion of the head and foot, but differ in the other changes that take place during this process. In PC 1 the viceral mass shortens, thereby emptying the shell apex, whereas the pallial cavity lengthens as the mantle collar slides toward the shell lip. In PC 2, on the other hand, the viceral mass length- ens, thereby partially filling the empty shell apex and slightly shortening the pallial cavity, with no shift in the mantle collar. The third principal component (PC 3) accounts for 19% of the total variance and primarily concerns a shortening of the pallial cavity as the mantle collar slides inward from the shell lip, and is weakly associated with shortening of the vis- ceral mass, emptying of the shell apex, and protrusion of the foot. PC 4, which accounts for 9% of the total variance, also involves re- traction of the mantle collar, but this time as- sociated with a lengthening of the pallial cav- ity and a slight evagination of the head. PC 1 and PC 2 were each significantly cor- related with the retraction/extension rank (= RETRAN) (Spearman coefficients —.61 and —.69, p = 0.0001 for both). PC 3 was very weakly correlated (—.28, p = 0.03), and PC 4 was uncorrelated (—.07, p = 0.63). Canonical correlation analysis between the set of shell variables and the set of soft-part distances yielded a single, highly significant (Wilks’ Lambda = 0, р = 0) canonical vari- ate, with a canonical correlation of 1.000. It is clear from the structure of this canonical vari- ate (Table 2) that it is an artifact due to the fact that EMPAPX + VICMASS + PALCAV + MANTLP = WHORLS. The true relationship between shell size and degree of retraction/extension is best shown by the squared multiple correlations between each soft-part distance and the ca- nonical variate (Table 2): they are negligible, ranging from 0.00 to 0.07, except for EM- PAPX (0.14). Thus, except for a very slight correlation between whorl count and the amount of empty apex, there is no real effect of shell size on the degree of retraction/ extension. External aspects of the four chosen stages of retraction/extension rank are shown in Fig. 2. Stage a (Fig. 2a) is fully extended, b (Fig. 2b) has just the head invaginated, c (Fig. 2c) has about half of the foot retracted within the body wall, and d (Fig. 2d) has most of the foot retracted within the body wall. Fig. 3 shows changes in the retractor mus- cle system, the head-foot, and the anterior digestive system during the four stages of re- traction/extension shown for the same four snails of Fig 2, in the same positions but in semi-diagrammatic mid-sagittal section. Fig. 4 shows changes in the nerve ring (= circum- esophageal ganglion = brain) during om- matophoral and head retraction. Figures 5-7 show changes in the reproductive system during the four stages of head-foot retraction, illustrated by the same specimens shown in Figs. 2 and 3. The sequence of muscular contractions during retraction (Fig. 3) is the same as that observed in Helix pomatia (Trappman, 1916; Jones, 1975): rhinophoral, ommatophoral, buccal, and then pedal. In stage a of retraction/extension (Fig. 3a), the rhinophores are invaginated. In stage b, the ommatophores are also invaginated within the body cavity, where they are pressed folded against the body wall by the head-foot. The head is nearly filled by the buccal mass, which contains the radular ribbon (with its generative sac), the odontophore, the jaw, and the highly complex musculature for ma- nipulating these structures through the mouth during a feeding stroke (Carriker, 1946; Run- ham, 1975). During retraction/extension, the positions of the buccal mass, the mouth, and the foot relative to each other remain fairly constant (Fig. 3). At full extension (Fig. 3a), the mouth (BO) is bounded by upper and lower lips (dark stippling) which lie above the anterior lobe of the foot (light stippling). The upper lip shields the sharp, chitonous jaw. As the head-foot is retracted (Fig. 3b—d), the up- per lip is overlapped by the lower lip, which in turn is overlapped by the anterior lobe of the foot. At extreme contraction (Fig. 3d), the mouth region is distorted: the anterior foot lobe and the lower lip, enclosed within the body wall, compress and stretch the upper lip. The buccal mass (B), because of its thick LAND-SNAIL RETRACTION/EXTENSION 161 = PCI 44% PC 3 19% во 2 24% ©) PC 4 9% FIG. 1. Components of retraction/extension in preserved snails. The structures of four principal components (PC 1 to PC 4) are shown that explain 96% of the total variance in six soft-part measurements between homologous landmarks. The relative contribution of each measurement is indicated by the width of its line, and the direction of its contribution by the arrowhead(s). musculature, remains relatively undistorted throughout retraction/extension (Fig. 3). The esophagus (О) is straight in stages a and b, but in stage c it has a kink and by stage d it is folded double, with the buccal mass in a pos- terior position. The stomach (IZ) is a simple sac in retraction/extension stages a and b, but the compression of stages c and d makes it appear to have two lobes. The cerebral nerve ring and its connectives are highly elastic. Fig. 4 shows in dorsal view how the nerve ring (N) is deformed during the earliest stages of retraction/extension of the buccal mass. During fullest extension (Fig. 162 EMBERTON TABLE 2. Canonical correlation between shell measurements and soft-part measurements associated with retraction/extension. Loadings of the variables are given on each of three canonical variates (CV), as well as the squared multiple correlation (R?) of each variable with all variables in the other set. Variable Shell: Diameter Height Whorls Body: MANTLP FOOTIP ANTENN PALCAV VICMAS EMPAPX CV1 CV2 CV3 0.30 ZO 0.90 1.05 0.50 —0.11 0.56 —0.39 =1.35 —0.76 1.29 0.97 —0.54 —0.25 0.37 0.69 —0.14 —0.23 R21 R?2 10 mm FIG. 2. Four stages (a-d) in the retraction/extension process: shell and head-foot. F = foot, MC = mantle collar, SL = shell lip. LAND-SNAIL RETRACTION/EXTENSION 163 Hi 5 mm FIG. 3. Four stages (a-d) in the retraction/extension process: digestive and retractor-muscle systems and the head-foot. B = buccal mass, BO = mouth, BR = buccal retractor muscle, F = foot, FR = pedal retractor muscle, IZ = stomach, О = esophagus, RT = inverted (retracted) ommatophore, Т = ommato- phore, TER = ommatophoral retractor muscle, TVR = rhinophoral retractor muscle. 4a), the nerve ring encircles the esophagus (О) and the two anterior ducts of the salivary gland (OG), just posterior to the buccal mass. As the buccal mass begins to retract, how- ever, it is pulled all the way back through the nerve ring (Figs. 4b and c). This process ini- tially stretches the nerve ring in all dimensions (Fig. 4b), then compresses it longitudinally (Fig. 4c), producing substantial changes in both size and shape of the dorsal cerebral ganglion (N, dark stippling). When retracted, the terminal portion of the reproductive system—from the genital pore to halfway up the prostate-uterus—is com- pressed between the retracted head-foot and the floor of the mantle cavity (Fig. 5). In the fully extended position (Fig. 5a), the genital pore (Y) opens on the right side of the head lateral to the anterior region of the buccal mass (B, stippled); the penis (P) is slightly bent and its retractor muscle (PR) is long and stretched; the vagina (V), spermatheca (S), 164 EMBERTON 5 mm FIG. 4. Changes in the nerve ring (stippled) during early retraction/late extension. B = buccal mass, N = nerve ring, О = esophagus, OG = salivary glands, ВН = retracted head. and prostate-uterus (UT) are straight. (In Figs. 5-7, | have not differentiated between the tightly bound prostate and uterus, but have labeled them UT instead of the proper DG-UT.) When the head and anterior foot are re- tracted (Fig. 5b), the genital pore is pulled back within the mantle collar (MC), adjacent to the retracted head-foot (RH-F, stippled); the buccal mass is pulled back to the level of the spermatheca; the penis is loosely con- torted; the vagina is bowed and folded at its junction with the spermatheca (not visible); the prostate-uterus is doubled back on itself as it folds against the retracting buccal mass. When the foot is half retracted (Fig. 5c), the genital pore retains its position near the apex of the retracted head-foot, the further retrac- tion of which pushes the pore back toward the penis; the penis therefore is tightly contorted and its retractor muscle is contracted; the va- gina is folded in half, with the apex of the fold held in place by connective tissue (not shown) to the anterior body wall; the prostate-uterus retains its tight folding adjacent to the buccal mass, which also apparently compresses the spermatheca (not labeled). When the foot is nearly completely re- tracted (Fig. 5d), it has slid further past the genital pore, pushing the penis inward so that its retractor muscle is stretched; the penis re- tains its tight contortion; the mid-way fold of the vagina remains attached by connective tissue to the anterior body wall, so that its length between this fold and the genital pore is stretched backward by the retracting head- foot; the prostate-uterus develops additional folds in the region of the further retracted buc- cal mass. Figures 6 and 7 show the removed repro- ductive system and the terminal genitalia at stages a through d of retraction/extension. Table 3 summarizes the means and standard deviations of the lengths of the vagina, sper- matheca, penis-plus-sheath, and penis-mi- nus-sheath calculated from five measured ‚ snails, each snail the average of three re- peated measurements. Vaginal length at full extension (stage a) averaged 4.5 mm, but when the head was invaginated (stage b), it only averaged 3.3 mm, a decrease of more than 25%. Later stages (c and d) of retraction actually increased the length of the vagina slightly to 3.6 mm (a 10% increase); as men- tioned previously, this is due to stretching the vagina between its distal ligamental attach- ment to the body wall and its proximal attach- ment to the retracting genital pore. These in- terstadial differences in vaginal length were significant (two-way nested ANOVA, F = 7.18; degrees of freedom = 3, 16; p < 0.005), despite the high and significant varia- tion among replicates at each retraction stage LAND-SNAIL RETRACTION/EXTENSION 165 5 mm == FIG. 5. Four stages in the retraction/extension process: reproductive system in relation to the buccal mass and retracted foot (both stippled). B = buccal mass, F = foot, MC = mantle collar, P = penis, PR = penial retractor muscle, RH-F = retracted head-foot, S = spermatheca, UT = prostate-uterus, V = vagina, Y = genital pore. In Fig. 5a, the genital pore opens toward the observer, whereas in 5b-d it opens away from the observer, into the space between the retracted foot and invaginated head skin, as indicated by the dashed circle around the pore. (F = 16.36; degrees of freedom = 16, 40; p <<0.001). | The spermatheca (= bursa copulatrix) was bound to the free oviduct (UV, Figs. 6 and 7) by connective tissue. Changes in the free ovi- duct were not quantified, but probably covar- ied with those of the spermatheca, the length of which was significantly affected by head- foot retraction (F = 9.55, p < 0.001), butin a different way than vaginal length (Table 3). The spermatheca averaged 2.7 mm regard- less of whether the snail was fully extended (stage a) or had invaginated its head (stage b). By the time it retracted half of its foot 166 EMBERTON 5 mm FIG. 6. Four stages in the retraction/extension process: reproductive system dissected out from the body cavity. GD = hermaphroditic duct, GG = albumen gland, PR = penial retractor muscle, PS = penial sheath, S = spermatheca, UT = prostate-uterus, V = vagina, Y = genital pore, Z = posterior digestive gland plus gonad. (stage c), however, its spermatheca was shortened to 2.2 mm (an 18% reduction). Full foot retraction (stage d) shortened it even fur- ther to 2.0 mm. Within each of these retrac- tion stages, however, there was highly signif- icant variation among replicate snails (F = 5.14, p << 0.001), as evidenced by the high standard deviations in Table 3. The length of the penis and its sheath showed a retraction-stage pattern similar to that of the vagina (Table 3). Head invagina- tion (stage b) reduced its average length from 6.4 to 5.5 mm (a 14% reduction), which was maintained (stage c) until extreme foot retrac- tion (stage а) stretched it slightly to 5.7 тт (a 5% increase). Extreme variation among rep- licates (F = 6.77, p << 0.001) kept this re- traction effect just short of statistical signifi- cance (F = 2.62, 0.05 < р < 0.10). The length of the penis without the sheath varied insignificantly (F = 1.92, 0.10 < р < .25), but in the same manner as penis-plus- sheath length (Table 3). There was extreme variation among replicates (F = 4.97, p << 0.001). The degree of retraction/extension had no effect on penial sculpture or on my ability to _ view it by dissection. Fig. 6 shows the com- plete reproductive systems, dissected free from the body cavity, of stages a-d. Despite increasing contortion of the penis and its sheath (PS) from stages a through d, the pe- nis could always be stretched out with pins in a dissecting dish, slit longitudinally, and pinned open to reveal its functional surface (Fig. 7). In the dissections shown in Fig. 7, the vas deferens (VD) has been cut and the pe- nial sheath has been cut near its apex in order to stretch out the upper part of the penis, which normally lies tightly coiled within the sheath (Solem, 1985, fig. 243). The sculpture of the lower part of the penis consists of two smooth, longitudinal pilasters (PP), the left of which—i.e. appearing on the LAND-SNAIL RETRACTION/EXTENSION 167 FIG. 7. Four stages in the retraction/extension process: terminal genital tracts, pinned out and dissected open. P = penis, PP = penial pilasters, PR = penial retractor muscle, PS = penial sheath, S = sper- matheca, UT = prostate-uterus, UV = free oviduct, V = vagina, VD = vas deferens, Y = genital pore. left side of the dissection, which is actually on the right side of the everted penis—is narrower than and stands about twice as high as the right. The ventral space between these two pilasters is smooth, but the dorsal penial wall is sculpted with longitudinal ridges, which are thin and numerous at the penial apex, but which anastomose in various 168 EMBERTON TABLE 3. Lenaths of the terminal genital tracts at four stages of retraction/extension. Means and standard deviations are based on five snails per stage. Measurement a Vaginal Length 4.5 (0.7) Spermathecal Length Pat (0.2) Penis + Sheath Length 6.4 (0.4) Penis — Sheath Length 2.1 (0.3) Stage of Retraction/Extension b С а oS 3.6 3.6 (0.4) (0.3) (0.2) 2.7 2.2 2.0 (0.4) (0.2) (0.3) 5.5 5.4 БИ (0.9) (0.5) (0.6) Uses 1.8 1.9 (0.2) (0.3) (0.2) TABLE 4. Penial sculpture as measured at four stages of retraction/extension. Retraction/ Left Right Extension Pilaster Pilaster Stage Width (mm) Width (mm) a 0.18 0.20 (0.05) (0.06) b 0.17 0.20 (0.03) (0.04) С 0.18 0.23 (0.05) (0.03) d 0.17 0.22 (0.03) (0.04) patterns proximally to become thicker and less numerous. Measurements and counts of these fea- tures of penial sculpture (Table 4) show that they are extremely variable within the popu- lation and that there is no effect whatever due to the stage of retraction/extension. Averaged over all 20 specimens, the left pilaster width was 0.17 mm, with a coefficient of variation (CV) of 0.2; right pilaster width = 0.21 mm (CV = 0.2); number of apical dorsal ridges = 12.7 (CV = 0.2); number of mid-dorsal ridges = 5.9 (CV = 0.2); and central mid-dorsal ridge width = 0.08 mm (CV = 0.4). Table 5 gives values of the two indices of measurement precision, along with the means, standard deviations, and ranges of the variables as calculated from the third set of replicated measurements. The mean coef- ficient of variation (CV Mean) was lowest for shell diameter (0.001), and was 7 x this value for shell height and whorl-count, and 31x to 344 x this value for the soft-part distances between homologous landmarks. The second index, the percentage of spec- imens with zero CVs, indicates the percent- age of specimens for which the three repli- Dorsal Wall Ridges Number Width of Central Apical Mid Mid (mm) 13.6 6.4 0.09 (2.9) (1.3) (0.03) 12.4 5.4 0.08 (1.1) (0.5) (0.03) 12.3 5.8 0.07 (2.2) (2.2) (0.02) 12.6 6.0 0.08 (3.2) (0.7) (0.03) cated measurements were identical. Its value varied from 9% to 70% and the ranges of val- ues were equable between shell and soft-part variables (Table 5). The precision of the shell measurements is analyzed in more detail in Table 6. Re-mea- surement of a shell’s diameter gave precisely the same result 76% of the time, differed by 0.1 mm in 23% of the cases, and differed by 0.2 mm in only 1% of the cases. The greater imprecision of height measurements is evi- denced by both its percentage (55%) and its range (up to 0.3 mm) of deviations. Whorl counts were 70% repeatable, and of the de- viations, 93% (0.28/0.30) were off by only one-tenth whorl; no deviation exceeded two- tenths whorl. The results of variance-partitioning of the lengths of the terminal genitalia are presented in Table 7. Inthistable, the effects of retraction/ extension (four stages), individual variation (5 replicates per stage), and measurement error (three measurements per replicate) are sum- marized from analysis of variance for each of four genitalic measurements. For vagina length, over half of the total variation was due to retraction/extension, less than half was due LAND-SNAIL RETRACTION/EXTENSION 169 TABLE 5. Shell and soft-part measurements: univariate statistics and two indices of measurement precision. мн ЪннунЪЪУ ———————_—____ ees Precision Indices Variable Mean (SD) Range CV Mean (SD) CV=0 Diameter 17.1 (0.5) 15.9-18.3 0.001 (0.002) 64% Height 8.4 (0.3) 7.7-9.2 0.007 (0.005) 21% Whorls 5.0 (0.1) 4.85-5.25 0.007 (0.006) 32% MANTLP 0.05 (0.06) 0.00-0.20 0.344 (0.660) 70% FOOTIP 0.25 (0.15) —0.05-0.50 0.121 (0.139) 40% ANTENN 0.43 (0.16) 0.15-0.80 0.133 (0.152) 13% PALCAV 0.54 (0.07) 0.35-0.65 0.067 (0.069) 31% VICMAS 2.72 (0.30) 2.15-3.35 0.031 (0.046) 19% EMPAPX 1.55 (0.32) 0.9-2.3 0.087 (0.128) 9% TABLE 6. Deviations of repeated shell measurements from their grand means. Deviation units are 0.1 mm for diameter and height, and 0.1 whorls for whorl-count. The proportion of replicates (and its standard eviation) is given for each deviation unit. Measurement 0.0 Diameter 0.76 (0.10) Height 0.45 (0.03) Whorls 0.70 (0.04) Deviation + 0.1 + 0.2 or 0.3 0.23 (0.09) 0.01 (0.01) 0.45 (0.05) 0.10 (0.03) 0.28 (0.05) 0.02 (0.02) to individual variation (among the five snails measured for each stage of retraction), and less than a tenth was due to measurement error. For spermatheca length, over half of total variation was due to retraction/ex- tension, about one-fourth was due to individ- ual variation, and about one-fifth was due to measurement error. For penis-plus-sheath length, individual variation accounted for over half the total variation; retraction/extension accounted for one fifth, whereas measure- ment error accounted for over one fourth, of this variation. For penis-minus-sheath length, measurement error was high, accounting for over one third of the total variation; individual variation accounted for half, and retraction/ extension accounted for only about one tenth of the total variation in the length of the penis minus the sheath. DISCUSSION AND CONCLUSIONS Body Landmarks During Retraction/ Extension Interpreting the principal components (PCs) of retraction/extension (Table 1, Fig. 1) must allow for the facts that (1) since the six variables used in the analysis differ in their measurement precisions, their differences may show up as artifacts in the structure of one or more PCs; and (2) the variable AN- TENN should, in retrospect, have been mea- sured from the mantle collar rather than from the heart, which causes it to overlap PALCAV and therefore makes its interpretation more difficult in the context of PC structure. Retraction/extension of the head and the foot (ANTENN and FOOTIP) are strongly cor- related (PCs 1 and 2) because of their phys- ical connection, but apparently either end may slightly precede the other (PCs 3 and 4). During head-foot extension/retraction, the vis- ceral mass is either farther or closer to the shell apex (PCs 1 and 2), and the mantle col- lar is either closer or farther (PCs 1, 3 and 4) from the shell lip (Fig. 1, Table 1). Thus re- traction/extension involves a complex inter- play of body landmarks. This complexity may be due, at least in part, to confounding the two separate processes of retraction and exten- sion. Thus, for example, the mantle collar may be pulled along with the head-foot during extension, but may lag behind the head-foot during retraction. For this reason, the best single criterion for the state of retraction/ extension in preserved specimens is the po- sition of the tip of the foot relative primarily to the body wall, and secondarily to the shell lip. 170 EMBERTON TABLE 7. Partitioning of the total variance in the lengths of terminal genital tracts. Retraction/ Measurement Extension Vaginal Length 52% Spermathecal Length 55% Penis + Sheath Length 20% Penis — Sheath Length 12% Source of Variation Individual Measurement Variation Error 40% 8% 26% 19% 53% 27% 50% 38% Thus the mantle collar, which is often the most visible landmark through the shell of re- tracted snails, is unreliable as an indicator (compare Fig. 2c and d). When | ranked the deshelled specimens according to the position of the foot-tip rela- tive to the body wall (RETRAN), this index was significantly but not strongly correlated with PCs 1, 2, and 3. Thus, only RETRAN is a reliable general measure of retraction/ extension state as it distorts systematically important body organs. Effect of Shell Size Shell size is no predictor of the state of re- traction/extension. This conclusion does not come from canonical-correlation analysis be- tween the sets of shell variables and soft-part variables (Table 2), because the latter were measured as whorl increments and the sum of four of them equals the shell variable “Whorls” (thus the first, and only significant, canonical variate merely reflects this mathe- matical relationship). The conclusion results rather from the facts that the second and third canonical variates were not only non-signifi- cant but also biologically nonsensical, and that the multiple correlation of each soft-part variable with the set of shell variables was . zero to negligible (Table 2). Retraction/Extension and Systematic Characters The four stages | chose from the continuum of retraction/extension are fairly distinct and easily identified in deshelled specimens: full extension, head invagination, half retraction of the foot, and full retraction of the foot (Fig. 2a-d). The latter stages are difficult or impos- sible to identify without removing the shell, however, because the transition between the exposed foot and the folded body wall into which it retracts is seldom discernable through the shell and—sometimes—the man- tle (see Fig. 2c and а). Since the specimens did not fall into discrete categories, the four stages were chosen at equal distances (i.e. numbers of specimens) along the retraction/ extension continuum. For this reason, the five “replicates” of each retraction/extension “stage” are actually only five adjacent speci- mens in one region of the continuum; the sim- ilarity of replicates was probably greatest at the endpoints: full extension and full retrac- tion. Body retraction is effected by the sequen- tial contractions of four muscles that are pos- teriorly fused—the rhinophoral, ommatopho- ral, buccal, and pedal retractors. The sequence is the same in Helix pomatia (Trapp- man, 1916; Jones, 1975). It appears that suc- cessive muscles are not effective throughout the process of body retraction, but each reaches a limit of contraction, after which it folds as the next muscle(s) continue to con- tract (Fig. 3). Body retraction is remarkably rapid. For example, several species of poly- gyrid land snails retract too quickly to be fixed in extended condition by immersion in liquid nitrogen (Emberton, unpublished). Distortion of internal organs by the retrac- tion process differs widely in both its degree and its nature. The retractor muscles them- selves, despite drastic changes in length, shape, and both absolute and relative dis- tances among each other, retain their basic topology throughout retraction. The length of the foot is not greatly altered during body re- traction, if measured along the curvature of its sole (Fig. 3). The upper lip is extremely stretched during the final stage of retraction. The size and shape of the buccal mass is virtually unaffected, although this was not studied in detail. The esophagus undergoes extensive shape changes, but its overall length appears stable. Both size and shape of the stomach, however, are sensitive to the stage of body retraction (Fig. 3). One of the most drastic changes during re- traction occurs during its early stages. This is LAND-SNAIL RETRACTION/EXTENSION 171 when the buccal mass is pulled back through the nerve ring. The effects of the size and shape of the nerve ring and its constituent ganglia are major (Fig. 4). The distal reproductive system undergoes a great deal of distortion during body retrac- tion as it is displaced by both the buccal mass and the foot (Figs. 5 and 6). The lengths of the terminal tracts are often given in systematics accounts, but the recorded variation com- pounds individual variation, variation due to retraction state, and measurement error. The results of this study indicate clearly that body retraction contributes a_ significant amount of variation in the lengths of the ter- minalia, even when they are dissected free from the body and pinned out straight for measurement. In the case of the lengths of the vagina and the spermatheca, the effect of body retraction actually outweighed individual variation (Table 7). Thus, these tracts are not only bent and folded by retraction, but are also physically shortened. The effect of body retraction is nonlinear (Table 3), and the na- ture of the nonlinearity is likely to differ among species, so excluding the effect of body re- traction on the vaginal and spermathecal lengths for interspecific comparisons would be difficult indeed. This irremedial effect is quite profound: one-fourth retraction can re- duce the total length of the vagina by 25% and the spermatheca by 18%. (This caveat probably does not apply, however, to the ma- jority of snails having a long, thin-walled sper- mathecal duct.) Therefore, interspecific differ- ences can easily be rendered undetectable by employing retracted specimens. Measure- ment precisions for the vagina and sperma- theca were good (approximately 1/10 and 1/5 total variances [Table 6]), so interspecific comparisons using only fully extended spec- imens should be fairly reliable. The land-snail penis is frequently of great value in systematics because of its variability. Fortunately, body retraction/extention has no substantial effect on penial characters. For the length of both the total and the basal penis, the effect of retraction/extention was well below measurement error (Table 7). Also, no matter how distorted the penes were in retracted states (Figs. 5 and 6), it was always possible to quantitatively compare the sculptures of their functional surfaces by dis- section (Fig. 7). The widths of the two pilas- ters and of the central ridge of the penial wall and the numbers of dorsal wall ridges, al- though variable among individuals, were un- affected by the state of body retraction/ extension (Table 4). Measurement Precision The differences in precision of the shell measurements depended in part on the prob- lems of orienting the shells for diameter and height measurements, and of locating the zero-whorl notch for whorl counts. Ningbingia dentiens has a relatively low-spired shell ap- proximately equal in size to the tip of one of the human fingers used to hold and orient it for measurement with dial calipers. These factors make it difficult to judge the position of the coiling axis. Measuring the diameter re- quires holding the coiling axis parallel to the jaws of the calipers and rotating the shell on this axis until the maximum diameter is achieved. This rotation—it becomes slight and almost unnecessary with practice—helps locate the coiling axis and ensures that the maximum diameter is measured. The preci- sion of this measurement, therefore, is rela- tively high: 95% of repeated measurements lay within 0.5% of their mean, and no single error was greater than 1% of the grand mean. The measurement of shell height is sensi- tive to any tilt away from the coiling axis. Such tilt is especially difficult to detect and control in the plane perpendicular to the jaws of the cal- ipers. Rotation in this plane does not affect the measurement of the diameter. Because of this additional source of error the precision of height is lower than that of diameter: 95% of repeated measurements lay within 2.8% of their mean, and no single error exceeded 4% of the grand mean. Accurately locating the origin of the suture (Schindel, 1989)—the apical notch of zero whorls (see Emberton, 1985, fig. 1)—requires a perfectly clean apex and an incidental source of narrow-beam illumination. The re- sult was that 95% of repeated measurements lay within 2.8% of their mean, and no single error exceeded 4% of the grand mean. Thus, for this, on average, 8.4-by-17.1-mm, 5- whorled shell, whorl counts to the nearest 0.1 whorl were just as precise as height measure- ments to the nearest 0.1 mm, which were 1/7 as precise as diameter measurements to the nearest 0.1 mm. The applicability of this precision analysis to other gastropod studies is limited, depend- ing both on the size, shape, number of whorls, and ease of detection of the suture origin of the shell, and on the experience and care of 172 EMBERTON the investigator. On the other hand, its meth- odology should be broadly applicable to other studies. The indices (Table 5) and categori- zations (Table 6) of precision are useful, can be applied to any kind of measurement, and provide the kind of backup necessary to, but too often lacking in, morphometric studies (e.g. Gould & Woodruff, 1986). The precision of each soft-part distance de- pends on two main factors: the ease of locat- ing its landmarks, and its size. The mantle collar in this species is easy to see either flush with the shell lip or, when it is retracted up to 0.2 whorl, through the shell. Its distance (MANTLP) from the shell lip, another reliable landmark, is calculable with high precision. Because MANTLP is such a short distance however (mean = 0.05 whorl), the few devi- ations among replicated measurements are equal to or greater than its mean value. This combination of factors explains why, among all variables, MANTLP shows the highest pre- cision using the CV =0 index (70%), but the lowest precision (= highest value) using the CV-mean index (0.34) (Table 1). СУ =0 is the better index because of its independence from the size of the variable; MANTLP is a variable calculable with high precision. The tip of the foot is as easy to locate as the mantle collar, but the distance between these two landmarks (FOOTIP) has a lower preci- sion (CV =0 value = 40%) than MANTLP for two reasons. First, the mantle collar is a slightly less reliable landmark than the shell lip. Second, and most importantly, the everted foot—unlike in retracted foot—rarely follows the contour of the body whorl as it is depicted diagrammatically in Fig. 1. Instead, it is more or less straight (Fig. 2a and b), so imprecision enters in estimating its curved distance. Nonetheless, FOOTIP is the second most : precise soft-part distance. Slightly less precise (CV=0 value = 32%) is the distance between the mantle collar and the auriculo-ventricular junction of the heart, used as a truncated measurement of the pal- lial cavity (PALCAV). Although the mantle col- lar is a good landmark, the position of the heart, as mentioned in the Materials and Methods section, can be difficult to pinpoint, depending on its chromatic differentiation from surrounding tissues, its size (state of contraction? degree of distention by haemo- coelic pressure changes at death?), and the opacity of the overlying shell. Finding the retracted ommatophore was al- most always easy—it is very dark gray and shows well through the shell—but judging its anterior-most point involved error. Measuring the base of the ommatophore on an extended snail suffered from either guessing its position on an invaginated head, or estimating its curved distance (as for the everted foot), or both. Combining this imprecision with that of the heart made the distance between these two landmarks (ANTENN) fairly imprecise, with а CV=0 index value of 13%. In retro- spect, a better measurement of antennal re- traction (ANTENN) would have been the dis- tance between the ommatophore and the mantle collar (instead of the heart); this would have been more precise. There is apparently no way to improve the low precisions (CV=0 values = 19% and 9%) of measurements of the visceral mass (VICMAS) and the apex of the shell empty of (unoccupied by) body tissue (EMPAPX). The landmark common to these two variables, the apex of the visceral mass, is often quite diffi- cult to pinpoint. As mentioned in the Materials and Methods section, it can be obscured both by denatured fluid within the empty apex and by opacity of the shell, the apex of which re- ceives the earliest and heaviest abrasion. Finding this landmark is aided by thoroughly cleaning the umbilical pit and by manipulating the light source. The imprecision index of VICMAS (the distance between the heart and the apex of the viscera) reflects—as do the indices of all soft-part distances, to a lesser degree—my learning process in locating the landmarks. The least precise of all soft-part distances, EMPAPX, combines the discrimi- natory problem of the visceral apex with that of its other landmark, the suture origin, which was discussed above. In sum, soft-part distances (Table 5, Fig. 1) varied greatly in precision depending on their size and on the difficulty of locating and mea- suring their landmarks. The “CV mean” index was an indicator of size-related imprecision, and the “CV=0” index was an indicator of landmark-related precision. Both indices also include my improvement in discriminating dif- ficult landmarks. Relative Sources of Variation The results indicate clearly that body re- traction/extension contributes a significant amount of variation to the lengths of the ter- minal genital tracts, even when they are dis- sected free from the body and pinned oui straight for measurement. In the case of the LAND-SNAIL RETRACTION/EXTENSION 173 lengths of the vagina and the spermatheca (including duct), the effect of body retraction actually outweighed individual variation (Table 7). Thus, these tracts were not only bent and folded by retraction, but are also physically shortened. The penis is frequently of great value in systematics because of its variability, proba- bly due to sexual selection (e.g. Cain, 1982; Eberhard, 1985). Measuring the length of the penis of Ningbingia dentiens requires straightening the upper region that is tightly coiled within the penial sheath (Fig. 7). This doubtless contributed to the large error of measurement, which accounted for over one fourth of total variance in the total length of the penis (Table 7). Nevertheless, the mea- surement error for the basal penis, exclusive of the sheath, was even more imprecise, ac- counting for over one third of total variance in length. These are substantial components of variation that could easily interfere with any attempts at meaningful comparisons among populations or species. Fortunately, none of this measurement error affected the penial sculpture, as viewed by dissecting open the uneverted penial tube (Fig. 7), which can be a valuable source of systematic characters (e.g. Schileyko, 1978; Solem, 1985; Ember- ton, 1988). However, this study has shown quantitatively that intrapopulational variance in these characters can be quite high (Table 4). ACKNOWLEDGMENTS This work was carried out with the support of the following grants from the National Sci- ence Foundation: BSR-81-19208 to Alan Solem for fieldwork, and BSR-83-12408 to Alan Solem and BSR-87-00198 to the author for analysis. | am grateful to Alan Solem for criticising an early draft of the manuscript. LITERATURE CITED CAIN, A. J., 1982, On homology and convergence. Pp. 1-19 in: JOYSEY, K. A. & A. E. FRIDAY, eds., Problems of phylogenetic reconstruction. Systematics Association Special Volume No. 21, Academic Press, London & New York. CARRIKER, M. R., 1946, Morphology of the ali- mentary system of the snail Lynmaea stagnalis appressa Say. Transactions of the Wisconsin Academy of Sciences, Arts and Letters, 38: 1- 88. DALE, B., 1974, Extrusion, retraction and respira- tory movements in Helix pomatia in relation to distribution and circulation of the blood. Journal of Zoology, London, 173: 427-439. EBERHARD, W. G., 1985, Sexual selection and animal genitalia. Harvard University Press, Cam- bridge. EMBERTON, K. C., 1985, Seasonal changes in the reproductive gross anatomy of the land snail Tri- odopsis tridentata tridentata (Pulmonta: Polygy- ridae). Malacologia, 26: 225-239. EMBERTON, К. C., 1988, The genitalic, allozymic, and conchological evolution of the eastern North American Triodopsinae (Gastropoda: Pulmo- nata: Polygyridae). Malacologia, 28: 159-273. GOULD, $. J. & D. $. WOODRUFF, 1986, Evolu- tion and systematics of Cerion (Mollusca: Pulmo- nata) on New Providence Island: a radical revi- sion. Bulletin of the American Museum of Natural History, 182: 389-490. JONES, H. D., 1975, Locomotion. Pp. 1-32 in: FRETTER, V. & J. PEAKE, eds., Pulmonates, Volume 1, Functional anatomy and physiology. Academic Press, London & New York. RUNHAM, N. W., 1975, Alimentary canal. Pp. 53— 104 in: FRETTER, V. & J. PEAKE, eds., Pulmo- nates, Volume 1, Functional anatomy and phys- iology. Academic Press, London & New York. SCHILEYKO, A. A., 1978, On the systematics of Trichia s. lat. (Pulmonata: Helicoidea: Hygromi- idae). Malacologia, 17: 1-56. SCHINDEL, О. E., 1989, Architectural constraint on the coiled geometry of gastropod molluscs. In: ALLMON, W. & R. ROSS, eds., Biotic and abiotic factors in evolution. University of Chicago Press (in review). SOLEM, A., 1985, Camaenid land snails from Western and central Australia (Mollusca: Pulmo- nata: Camaenidae) V. Remaining Kimberley gen- era and addenda to the Kimberley. Records of the Western Australian Museum, Supplement No. 20, pp. 707-981. SOLEM, A. & C. CHRISTENSEN, 1984, Camaenid land snail reproductive cycle and growth patterns in semi-arid areas of north-western Australia. Australian Journal of Zoology, 32: 471—491. TRAPPMANN, W., 1916, Die Muskulatur von Helix pomatia L. Zeitschrifft für Wissenschafftlichen Zoologie, 115: 460-489. Revised Ms. accepted 5 July 1989 — hie. to TA (oe o L ne y 7 pre р УЖ, U he Fe erg R. 2d ; a So ©, | + u POSI E nur = > is 1 0 BETT vet Ju Vet Ge So = — ¡Pr Bin u u : R Ва Sa “qe eas ay | 1 a e ar DAN И ты y | | RIES IR DIVOADE rei) ПО nid ‘As ia er | un i i =~ ie 1 VR nf | 2 es ЕВА > i = de ON i> A р D К у - 1 Ss o a | Y > = \ — [1 v 1 wr | o 1 7 | ‘ ao 1 “ A we u N i i | + ® + eo | == 1 r - x - sn A k Lola ‘ | бы de E { 12 pe = z UN Es i 4 - + 7 р Ч { 1 i Я y и e N у р т ‘ у > ' MALACOLOGIA, 1989, 31(1): 175-195 BIOLOGY AND COMPARATIVE ANATOMY OF DIVARISCINTILLA YOYO AND D. TROGLODYTES, TWO NEW SPECIES OF GALEOMMATIDAE (BIVALVIA) FROM STOMATOPOD BURROWS IN EASTERN FLORIDA Paula M. Mikkelsen' & Rüdiger Bieler? ABSTRACT Two new galeommatid bivalves, Divariscintilla yoyo and D. troglodytes, are described as commensals in burrows of the stomatopod Lysiosquilla scabricauda from central eastern Flor- ida. They are remarkable in their snail-like appearance and behavior, due to elaborately orna- mented pallial layers enclosing the shell, and their ability to actively сгам on a highly mobile foot. Both are simultaneous hermaphrodites, brooding their larvae in the suprabranchial chamber prior to release of straight-hinged veligers. The two new species differ from one another in shell morphology, the number of secretory “flower-like organs,” and the nature and ornamentation of the mantle. They differ from the type and only other described species in this genus, D. maoria, primarily in shell characters, namely in anterior (rather than posterior) prolongation, and in the absence of a ventral cleft. The genus Divariscintilla, previously known only from New Zealand, is redefined with the following diagnostic characters: incompletely internalized shell with anterior or posterior prolongation, species-specific numbers of pallial tentacles and papillae, a two-part foot used in active crawling and “hanging” utilizing both byssus- and byssus adhesive glands, secretory “flower-like organs” on the anterior surface of the visceral mass, eulamellibranch ctenidia with interlamellar and interfilamentary junctions, and simultaneous hermaphroditism with larval brooding. Key words: Divariscintilla, Galeommatidae, Galeommatoidea, systematics, anatomy, Sto- matopoda, commensalism, Florida. INTRODUCTION A wide variety of mollusks are known to associate with other invertebrates in symbi- otic relationships. Galeommatoidean [= ga- leommatacean] bivalves are among the best known symbionts (Boss, 1965, as Erycina- cea), and are interesting in the anatomical and behavioral modifications associated with their specialized mode of life. These include (1) internalization of the shell by the middle pallial fold, (2) elaboration of this pallial layer by tentacles and papillae, (3) snail-like loco- motion on a highly extensible foot, and (4) the occurrence of hermaphrodites or dwarf males. Anatomical data are available for spe- cies in less than 30 of the approximately 110 Recent, presumably valid genera (Vokes, 1980; Chavan, 1969). Within the family Galeommatidae Gray, 1840, the monospecific genus Divariscintilla Powell, 1932, was originally based on empty shells of the New Zealand species D. maoria Powell, 1932. Distinguishing shell characters include a deep ventral notch, a strongly ob- lique posterior prolongation, and dentition lim- ited to a small conical tooth in each valve. The anatomy and biology of D. maoria were sub- sequently described by Judd (1971) from specimens found living in the burrows of the stomatopod crustacean Heterosquilla tricari- nata (Claus). A study of organisms associated with the sand-burrowing stomatopod Lysiosquilla sca- bricauda (Lamarck) in shallow waters in eastern Florida has yielded a number of undescribed or poorly known molluscan species. Data on the two species of vitrinellid gastropods in the burrows have appeared elsewhere (Bieler & Mikkelsen, 1988). Five previously undescribed species of galeom- matid bivalves were also encountered, and two, assignable to Divariscintilla, are here described. The data presented here identify anatomical characters of value at the generic level and represent a step toward clarification of the taxonomic disorder in this super- family. ‘Indian River Coastal Zone Museum, Harbor Branch Oceanographic Institution, 5600 Old Dixie Highway, Ft. Pierce, Florida 34946, and Dept. of Biological Sciences, Florida Institute of Technology, Melbourne, Florida 32901 U.S.A. “Delaware Museum of Natural History, Р.О. Box 3937, Wilmington, Delaware 19807 U.S.A. 176 MIKKELSEN & BIELER MATERIAL AND METHODS Stomatopod burrows in shallow-water sand flats in the Indian River lagoon just inside the Ft. Pierce Inlet, St. Lucie County, eastern Florida (27°28.3'N, 80°17.9'W), were sam- pled using a stainless steel bait pump (“yabby pump”) and sieves of 1-2 mm mesh. Depths during extreme low water ranged from less than 0.5 m to supratidal, wherein the water level lay several centimeters below the level of the sand. Living clams were maintained in finger bowls of seawater at room temperature (24°C). Behavioral studies were aided by video recordings taken of the living animals in aquaria using a standard commercial 1/2- inch-format video camera equipped with a macro lens. Carmine and fluorescein sodium particles aided observation of ciliary action and cur- rents produced by the animals. Relaxation prior to dissection or preservation was most effectively accomplished with menthol crys- tals, floated on the seawater surface, or with crystalline magnesium sulfate, added directly in small, gradual amounts. Methylene-blue/ basic-fuchsin and neutral red were used to delineate tissues and organs in gross dissec- tions. For histological serial sections, animals were fixed in either a glutaraldehyde-formalin solution (4% formalin, 2.5% glutaraldehyde in 0.1M phosphate buffer, pH 7.2) or in 5% buff- ered formalin (Humason, 1962: 14). Shells were decalcified using either dilute hydrochlo- ric acid (complete decalcification within min- utes, however, with bubble production pre- senting technical histological difficulties) or a 1% solution of ethylene diamene tetraacetic acid (EDTA, adjusted to pH 7.2; decalcifica- tion complete over a period of 5-6 days). Specimens were embedded in paraffin, sec- tioned at 5-7 um and stained with alcian blue/ periodic-acid-Schiff (PAS), counterstained with Harris’ hematoxylin/eosin (Humason, 1962: 125, 269, 298), hereafter referred to as APH. Staining reactions described in the text refer to this method unless otherwise noted. Colors referred to in the text are supplied for future use, e.g., to infer homologies of the var- ious glands. Other similarly prepared speci- mens were stained with hematoxylin/eosin. The section in Fig. 23 was fixed in Kar- novsky's fixative (Karnovsky, 1965), post- fixed in 1% osmium tetroxide in a phosphate buffer, dehydrated through an ethanol propy- lene oxide series, embedded in Epon-812, sectioned at 1 um and stained with Richard- son's stain (Richardson, et al., 1960). Photo- micrographs of sections were taken either with a Zeiss Photomicroscope-3 or an Olym- pus BH-2 stereomicroscope fitted with an Olympus OM-2 camera. For scanning electron microscopy (SEM), partially dissected preserved specimens were passed through an ethanol-to-acetone series and critical-point dried. These and air-dried shells were coated with gold/palladium and scanned using a Zeiss Novascan-30. All cited anatomical measurements were taken from specimens of average size (ap- proximately 10-15 mm mantle length). Be- cause of the extreme expansivity and con- tractility of the mantle, it is difficult to accurately measure “length” of a living animal of this type. Approximate mantle length was measured along an anteroposterior axis from an animal in normal crawling or hanging pos- ture; throughout the text, this is expressed as “relaxed” and does not refer to any chemical treatment of the animals. Measurements of type specimens refer to preserved mantle lengths. Shell length is expressed as the max- imum dimension, i.e. an oblique anteropos- terior length. Cited institutions are (* indicates location of type and other voucher material): AMNH— American Museum of Natural His- tory, New York *DMNH— Delaware Museum of Natural His- tory, Wilmington Harbor Branch Oceanographic In- stitution, Ft. Pierce, Florida *IRCZM— Indian River Coastal Zone Mu- seum, HBOI Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts SMSLP— Smithsonian Marine Station at Link Port, Ft. Pierce, Florida *USNM— National Museum of Natural His- tory, Smithsonian Institution, Wash- ington, D.C. HBOI— *MCZ— TAXONOMIC DESCRIPTIONS Family GALEOMMATIDAE GRAY, 1840 Gray (1840: 154) introduced the family name Galeommidae for Galeomma Turton, 1825 (erroneously spelled “Galeomidae” by BIOLOGY OF DIVARISCINTILLA 1777. Gray, 1842: 78). It has been used in that form by various authors (e.g. Н. & A. Adams, 1857; Tyron, 1872; Kisch, 1958). Dall (1899: 875) emended the spelling without explanation to Galeommatidae, and it is this form that is now in common use (e.g. Thiele, 1934; Popham, 1939; Vokes, 1980; Chavan, 1969; B. Morton, 1973; Abbott, 1974; Boss, 1982). Dall’s action was a justified emendation of an incorrect original spelling [ICZN, 1985: Art. 29(b)(i), 32(c)(iii)] because the Greek noun öuua pro- vides the stem ommat- for the formation of the family name. As a justified emendation, Ga- leommatidae bears Gray, 1840, as authority and date [ICZN, 1985: Arts. 11(f)(ii), 19(a)(i)]; the name of the superfamily is accordingly Galeommatoidea [= Galeommatacea] Gray, 1840. The nominal superfamilies Leptonoidea Gray, 1847; Erycinoidea Deshayes, 1850; and Chlamydoconchoidea Dall, 1889, are here considered junior synonyms. DIVARISCINTILLA POWELL, 1932: 66. Type species: Divariscintilla maoria Powell, 1932 (by original designation). Recent, New Zealand. DIVARISCINTILLA YOYO, SP. NOV. (FIGS. 113156, 8—11, 26) Material examined: Holotype: 5.3 тт [рге- served mantle length], USNM 860036. Para- types (8): 5.8, 4.7 mm, USNM 860037; 8.3, 7.5 mm, MCZ 297406; 6.0, 5.2 mm, IRCZM 064:01721; 5.7, 4.7 mm, DMNH 175516. To- tal material: 83 specimens: FLORIDA: Ft. Pierce Inlet: March 1987, 4; 2-3 May 1987, 19 (including MCZ paratypes); 24 June 1987, 4; 03 August 1987, 6; 14 August 1987, 7; 31 August 1987, 17 (including USNM, IRCZM, and DMNH type specimens); 28 December 1987, 1; 11 March 1988, 2; 12 April 1988, 13. — Sebastian Inlet: 30 December 1987, 10. Type locality: Ft. Pierce Inlet, St. Lucie County, Florida, 27°28.3'N, 80%17.9'W, in Lysiosquilla scabricauda burrows on intertidal sand flats with patches of the seagrass Halodule wrightii Ascherson. Diagnosis Animal translucent white. Mantle thick, sur- face granular, falling into large creases. Two long “cephalic” pallial tentacles; one very short mid-dorsal tentacle just anterior to ex- current siphon. Shell wedge-shaped, elon- gate-pointed anteriorly, with weak internal ribs, length approximately 40% of extended mantle length. “Flower-like organs” on ante- rior surface of visceral mass ventral to labial palps, numbering 3-7 (usually 5). Description External features and mantle: Living ex- tended animal (Fig. 1) 10-15 mm in length, globular in general shape, entirely translucent white, except for dark upper portion of diges- tive gland. Shell nearly completely enclosed by thick mantle with granular external surface (Fig. 6; formed by middle pallial fold) falling into large creases, and with sparse, minute papillae; mantle thinner, more translucent, and with scattered, relatively larger papillae in smaller (approximately 7 mm) specimens. Anteropedal pallial opening wide, forming ex- tensive anterior cowl (Fig. 1, с). Two long, retractable, “cephalic” tentacles (Fig. 1, ср) anterodorsally just behind cowl. Very short (< 1 mm) median pallial tentacle (Fig. 1, mpt) on dorsal midline anterior to excurrent siphon (Fig. 1, exs). Each tentacle with central core of longitudinal muscle and nerve fibers, visi- ble as an inner thread under low magnifica- tion. Mantle fused dorsally from edge of cowl to excurrent siphon located posterodorsally and often on conspicuous rounded protuber- ance (dependent on degree of pallial expan- sion); fusion interrupted only by small circular (approximately 2 mm diameter) foramen (Fig. 1, uf) just over umbo of shell. Mantle fused posteroventrally from excurrent siphon to mid-ventral point (Fig. 1, mf) at posterior end of anteropedal opening. Inner pallial fold highly muscular; fibers continuous with mus- cles of central “core” of tentacles. Preserved animals characterized by gen- eral globular appearance, with retracted cephalic tentacles, mantle-covered shell (with small foramen over umbo), contracted cowl and excurrent siphon. Foot usually com- pletely withdrawn into pallial cavity. Shell (Figs. 8-11). Thin, transparent to translucent white except for yellow prodisso- conch and network of opaque white coloration on early portion; equivalve, showing fine growth lines; oval initially, changing to ащеп- orly elongate-pointed with angulate corners anteriorly and posteriorly near attachment points of adductor muscles; weak internal ra- dial ribs corresponding in placement to weak 178 MIKKELSEN & BIELER conti uf she mpt FIGS. 1-5. External appearance and internal shell morphology. 1. Divariscintilla yoyo in crawling position, from left side. 2. D. troglodytes, same as Fig. 1. 3. D. yoyo, internal surface of right valve, showing approximate location of muscle insertions. 4. D. troglodytes, same as Fig. 3. 5. D. yoyo, in hanging position, from right side. Scale bars: 1, 2, 5 = 2.0 тт; 3, 4 = 1.0 mm. (aam, anterior adductor muscle; apr, anterior pedal retractor muscle; apt, anterior pallial tentacle; bag, byssus adhesive gland; by, byssus; byg, byssus- gland; с, cowl; cpht, cephalic tentacles; ct, ctenidium; exs, excurrent siphon; fl, flower-like organ; ft, foot; mf, point of ventral mantle fusion; mpt, median pallial tentacle; pam, posterior adductor muscle; pef, posterior extension of foot; ppm, pedal protractor muscle; ppr, posterior pedal retractor muscle; ppt, posterior pallial tentacles; sh, shell; uf, umbonal foramen; vgr, ventral groove). external grooves. Muscle scars _ indistinct. Hinge (Fig. 10) primarily internal, with weak external ligament, stronger internal resilium and two rudimentary, non-interlocking cardi- nal teeth; lateral teeth absent. Shell nearly completely enclosed in chamber formed by pallial layers, communicating with exterior via small umbonal foramen (Fig. 1, uf). Perio- stracal groove lying between inner and outer pallial folds. Size small in relation to body, extending only over dorsal portion of visceral mass; length approximately 40% of relaxed mantle length. Permanently gaping at 110— 120° angle while relaxed, incapable of closure more than 50°. Periostracum colorless, most evident as periostracal webbing extending between valves, anterior and posterior to hinge, and at periphery of shell. Shell micro- structure (Fig. 11) cross-lamellar, with thin ho- mogeneous layer on either side. Prodissoconch (Fig. 16) approximately 350 шт in length, having distinct prodissoconch | ‚ and prodissoconch II stages; prodissoconch | approximately 140 um in length, with “granu- lated” surface sculpture and marginal radial ridges; prodissoconch II stage relatively large, sculptured with distinct concentric ridges. Abrupt demarcation between prodissoconch and dissoconch. Organs of the pallial cavity: Foot (Figs. 1, 5, 18-19, ft, pef) highly extensible, with hatchet-shaped anterior crawling portion and elongated tubular posterior extension. Ante- rior portion internally with dorsal haemocoel, sparse longitudinal musculature, and with ex- tensive lateral and ventral external ciliation and accompanying mucous glands (staining turquoise to dark blue in APH). Ventral groove (Figs. 1, 18, 21, vgr) extending from approx- BIOLOGY OF DIVARISCINTILLA 179 FIGS. 6-7. Exterior pallial surfaces (SEM). 6. Divariscintilla yoyo. 7. D. troglodytes; arrows indicate enlarged pallial papillae. Scale bars = 50 um. imate midpoint of anterior tip to terminus of posterior extension, heavily ciliated interiorly along entire length. Byssus-gland (Figs. 1, 21, byg) restricted to very small area on either side of ventral groove, a short distance be- hind anterior end of groove in vicinity of pedal ganglia (see below); closely associated with numerous blood spaces; faintly whitish in liv- ing animal, staining dark blue in methylene blue, purple in APH. Posterior extension ter- minally pointed (Fig. 19), consisting internally largely of longitudinal muscle fibers and con- nective tissue; proximal half with free edges of ventral groove heavily ciliated externally; external ciliation and accompanying mucous glands disappearing abruptly to leave distal half of posterior extension with ciliation re- stricted to interior of groove. Byssus adhesive gland [Figs. 1, 22, bag; see Ecology and Be- havior (below) for explanation of term] just short of terminus of posterior extension, with internal lamellae surrounding a common lu- men; opaque white in living animal, staining dark blue in methylene blue, light purple in APH. Anterior and posterior adductor muscles subequal, long, of moderate diameter. Attach- ment ends oval, subequal. Anterior pedal re- tractor slightly smaller in diameter than, and attaching to shell anterior to, anterior adduc- tor; posterior pedal retractor smaller than, and attaching to shell posterodorsal to, posterior adductor. Very small pedal protractor attach- ing to shell dorsal to anterior adductor. Integument of visceral mass with numerous longitudinal muscle fibers, most highly con- centrated posteriorly; these continuous with anterior and posterior pairs of pedal retractor muscles, only slightly smaller in diameter than adductor muscles. Small anterior pedal pro- tractor originating ventral to anterior adductor muscle within anterior tissues of digestive gland, passing posterodorsally to insert on shell, dorsal to anterior adductor. Muscles leaving no visible attachment scars on shell; approximate insertion locations shown in Fig:.3: Labial palps (Fig. 28, Ip) large, oval, each with 10-14 lamellae each side; each pair fused at midline near mouth. Outer palps at- tached laterally by elongated strip of tissue to inner surface of mantle lining shell; inner palps similarly attached to surface of visceral mass. Cilial currents moving particles oral- ward on inner palp surfaces, laterally toward ctenidia on outer palp surfaces. Ctenidia (Fig. 25) eulamellibranch, homorhabdic, hanging in loosely pleated folds, with numerous fila- ments; inner and outer demibranchs on each side with both ascending and descending lamellae. Both demibranchs with well-devel- oped, numerous interfilamentary junctions (Fig. 24, ifj; Fig. 25, arrow), and evenly dis- tributed, albeit few, interlamellar junctions (Fig. 24, ilj). Inner demibranch approximately 50% larger, extending farther ventrally and anteriorly than outer, with food groove (Fig. 25, fg) at free edge; anterior end (with termi- nus of food groove) extending between labial palps. Ventral tips of anterior filaments of in- 180 MIKKELSEN & BIELER FIGS. 8-15. Shells and shell structure (SEM). 8. Divariscintilla yoyo, left valve, external view, 3.9 mm [maximum dimension]. 9. D. yoyo, right valve, internal view, 3.0 mm. 10. D. yoyo, hinge, anterior to left. 11. D. yoyo, microstructure, with internal surface at top. 12. D. troglodytes, same as Fig. 8, 5.9 mm. 13. D. troglodytes, same as Fig. 9, 5.3 mm. 14. D. troglodytes, same as Fig. 10. 15. D. troglodytes, same as Fig. 11. Scale bars: 10 = 100 pm; 11, 15 = 5 рт; 14 = 200 um. BIOLOGY OF DIVARISCINTILLA 181 FIGS. 16-17. Prodissoconch and larval shell morphologies (SEM). 16. Prodissoconch (Divariscintilla yoyo); arrow indicates boundary between prodissoconch | and II. 17. Shell of newly hatched larva (D. troglodytes); arrow indicates zone of initial shell formation. Scale bars: 16 = 50 um; 17 = 10 pm. FIGS. 18-19. Foot (SEM). 18. Ventral view of entire foot, showing ventral groove (Divariscintilla troglodytes). 19. Terminus of posterior foot extension, showing byssus-threads (D. yoyo). Scale bars: 18 = 200 „m; 19 = 50 um. (by, byssus; pef, posterior extension; vgr, ventral groove). ner demibranch “not inserted into a distal oral groove” (Stasek, 1963, Category III); antero- ventral margin of inner demibranch fused to inner palp lamella. Outer demibranch shorter, without food groove; margins inserting be- tween inner and outer labial palps, along up- per portion of visceral mass, and on inner sur- face of mantle to posterior end of pallial cavity. Cilial currents as in Fig. 30, moving food particles in food groove and in groove between demibranchs oralward. Tract on in- ner surface of cowl anterior to palps as exit point for removal of waste particles. No cilial currents evident on inner pallial surface or surface of visceral mass. Visceral mass of brownish digestive gland anterodorsally, whitish granular-appearing gonad posteriorly, distally, and, in ripe speci- mens, overlapping digestive tissue laterally and dorsally; red pedal ganglia visible at distal end of gonad in base of foot. Cluster of 3-7 (most often 5; х = 4.7,n = 31) nonretractable “flower-like organs” (Figs. 23, 26) originating on anterior surface of vis- ceral mass just ventral to labial palps. Usually arranged as single organ closest to palps, 182 MIKKELSEN & BIELER FIGS. 20-24. Internal structure, histological sections. 20. Cross-section at level of esophagus and anterior edge of ctenidia (Divariscintilla yoyo). 21. Cross-section through foot at region of byssus-gland (D. yoyo). 22. Longitudinal section through byssus adhesive gland at terminus of posterior foot extension (D. yoyo). 23. Longitudinal thin section through two “flower-like organs” (D. yoyo). 24. Cross-section of ctenidium showing interlamellar and interfilamentary junctions (D. troglodytes). Scale bars: 20 = 300 um; 21, 24 = 100 um; 22, 23 = 50 um. (bag, byssus adhesive gland; Буд, byssus-gland; ct, ctenidium; dg, digestive gland; es, esophagus; gon, gonad; idb, inner demibranch; ifj, interfilamentary junctions; ilj, interlamellar junctions; lam, lamellae of byssus adhesive gland; Ip, labial palp; man, mantle; mg, midgut; mug, mucous glands; mus, muscle fibers; odb, outer demibranch; pef, posterior extension of foot; pg, pedal ganglia; pn, pedal nerve; sh, shell; ss, style sac; vgr, ventral groove). BIOLOGY OF DIVARISCINTILLA 183 FIG. 25. Ctenidia of Divariscintilla yoyo (SEM). Ar- rows indicate interfilamentary junctions. Scale bar = 100 um. (fg, food groove of inner demibranch; idb, inner demibranch; odb, outer demibranch). with successive organs commonly originating in pairs, ventral to first; more ventral pairs of- ten slightly smaller. Tendency for more nu- merous “flower-like organs” in larger speci- mens (= 5 in specimens of shell length < 4.0 mm; > 5 in specimens of shell length > 4.0 mm), but highly variable (smallest specimen = 2.1 mm shell length with 5 organs; largest specimen = 5.8 mm shell length with 5 or- gans; specimens of 2.6 and 4.7 mm shell length with 7 organs each). Each organ 0.3— 0.7 mm in diameter, 0.5 mm in height (in- cluding “head” plus stalk); head composed of numerous (80-90), onion-shaped subunits, each opening to exterior via large pore (Fig. 23); homogeneous stalk of blood-filled spongy connective tissue, without lumen and without obvious nervous connection. Digestive system: Mucous glands embed- ded in bases of labial palps surrounding mouth and anterior esophagus. Short esoph- agus leading from mouth into stomach at dor- sal center of visceral mass. Stomach (Fig. 28, st) round or oval, slightly elongated antero- posteriorly. Major openings into stomach in- clude those from: (1) esophagus (eso), open- ing anteriorly, (2) right and left digestive ducts (dd), Opening posteroventral to esophageal opening, (3) left pouch (Ipch), adjacent to left digestive duct, and associated with shallow dorsal pocket [dorsal hood (dh)], (4) style sac (Ss), Opening posteroventrally, and (5) midgut (mg), Opening just anterior to, but morpholog- ically separate from, style sac. Major typhlo- sole (ty) on mid-ventral surface of stomach as wide loop extending from midgut and style sac to right digestive duct. Faintly ridged ar- eas (?sorting areas) present, adjacent to esophageal opening and between edge of gastric shield and major typhlosole. Many small ducts to digestive gland opening into right and left digestive ducts and left pouch. Gastric shield (Fig. 28, gs and A) with thick- ened knob-shaped dorsal projection (upon which crystalline style rotates) attached to tis- sue flap between left digestive caecum and left pouch; remainder of gastric shield thin, wrapped around dorsal end of crystalline style with dorsal extension forming narrow channel into dorsal hood. Style sac extending nearly entire length of visceral mass, with ventral tip visible exter- nally within gonadal tissue on left side of foot; internally with typhlosole on anterior wall con- tinuing into stomach and communicating with major typhlosole; crystalline style (Fig. 28, cs) extending entire length of style sac, sharply tapered at distal end. Midgut (mg) with 2-3 loops within anterior part of visceral mass, of- ten visible just below surface of integument on either side; typhlosole initially large, de- creasing in size rapidly; extending to distal end of visceral mass on right side, near tip of style sac, where it loops back to pass directly dorsal [as hindgut (hg)] near surface along posterior right side of gonad, leaving visceral mass near region of heart. Rectum (re) pass- ing posteriorly through heart and kidney; rec- tal glands absent. Anus (Figs. 28, 29, an) po- sitioned just inside excurrent siphon. Fecal strands of irregular length and varying width. Suprabranchial chamber (Fig. 29). Re- ceives openings of gonad, kidneys and diges- tive system. Two oval, whitish, glandular patches [?hypobranchial glands (hgl)] on roof of suprabranchial chamber, flanking rectum. 184 MIKKELSEN & BIELER FIGS. 26-27. Flower-like organs (SEM). 26. of Divariscintilla yoyo, showing typical number of five, of subequal size. 27. of D. troglodytes, in lateral view. Scale bars: 26 = 100 um; 27 = 50 um. Nervous system (Fig. 31). Nervous system of typical bivalve organization with three pairs of ganglia, red in living animal, connected by long commissures. Ganglia relatively large, subequal (length approximately 0.4 mm), cerebropleural ganglia more elongate than others. Cerebropleural ganglia (cplg) lying just anteroventral to anterior adductor mus- cle, dorsal to esophagus; cerebral commis- sure (cc) short; each ganglion giving rise to three additional major branches: (1) dorsally, common trunk giving rise to cephalic tentac- ular nerve (ctn) leading to cephalic tentacle, and pallial nerve (paln) leading to ventral shell edge as a continuous cord (to visceral gan- glion) with numerous smaller nerves extend- ing into mantle tissue; (2) ventrally, cere- bropleural-pedal commissure (cpc) passing between visceral mass and integument along anterior face of foot, penetrating gonadal tis- sue distally to join with pedal ganglion; and (3) laterally, cerebrovisceral commissure (cvc) passing through upper portion of visceral mass to visceral ganglion. Pedal ganglia (Figs. 21, 31, pg) closely fused at midline; showing through integument of foot in living animal as red organ at extreme distal end of gonad; each dorsally receiving cerebropedal commissure from cerebropleural ganglion; each ventrally giving rise to two anterior and one posterior pedal nerves. Statocyst (Fig. 31, stc) on posterodorsal face of each pedal ganglion; each with one spherical statolith (stl) 50 um in diameter. Visceral ganglia (vg) joined together at midline (but not as closely fused as pedal ganglia), lying ventral to heart, posteroventral to posterior adductor muscle; each receiving cerebrovisceral commissure (anterolaterally) and pallial nerve (dorsolater- ally) from cerebropleural ganglion; each giv- _ ing rise ventrolaterally to branchial nerve (with somewhat swollen base), which extends along common axis of inner and outer demi- branchs of ctenidium. Reproductive system: Simultaneous her- maphrodite. Ovotestis white, encompassing most of volume of visceral mass, extending from small portion in umbonal area, down posterior surface of digestive gland, and ex- panding to surround pedal ganglia and ventral extensions of style sac and intestinal loops. “Spent” appearance sparse, with pedal gan- glia fully exposed at terminus, and with silvery ducts clearly visible, packed with mature spermatozoa. Common genital ducts with large ciliated openings, emptying into supra- BIOLOGY OF DIVARISCINTILLA 185 pg apn PPN FIGS. 28-31. Anatomical structures in Divariscintilla species. 28. Visceral mass, from right side, showing stomach, opened laterally. Midgut (mg) with four cross-sections, showing reduction of typhlosole. (A) = gastric shield, excised. 29. Roof of suprabranchial chamber, with anterior end up and inner lamellae of right and left inner demibranchs removed. 30. Diagrammatic representation of ctenidial demibranchs in cross- section, showing cilial currents. 31. Nervous system (semi-diagrammatic). Tentacles with nerves drawn as broken lines present only in D. troglodytes; remainder identical for both species. Sizes of ganglia and lengths of nerves not drawn to scale. Scale bars = 1.0 mm. (an, anus; apn, anterior pedal nerves; aptn, anterior pallial tentacular nerve; bn, branchial nerve; cc, cerebropleural commissure; cpc, cerebropleural-pedal commissure; cs, crystalline style; cplg, cerebropleural ganglion; ct, ctenidium; сп, cephalic tentacular nerve; cvc, cerebropleural-visceral commissure; dd, right and left digestive ducts; dg, digestive gland; dh, dorsal hood; eso, esophageal opening; exs, excurrent siphon; fl, flower-like organs; ft, foot; go, gonadal opening; gon, gonad; gs, gastric shield; hg, hindgut; hgl, ?hypobranchial gland; idb, inner ctenidial demibranch; Ki, kidney; kio, kidney opening; Ip, labial palps; Ipch, left pouch; mg, midgut; mptn, median pallial tentacular nerve; odb, outer ctenidial demibranch; рат, pallial nerve; pam, posterior adductor muscle; pg, pedal ganglion; ppn, posterior pedal nerve; ppr, posterior pedal retractor muscle; pptn, pallial tentacular nerve; re, rectum; sh, shell; ss, style sac; st, stomach; stc, statocyst; stl, statolith; ty, major typhlosole; vg, visceral ganglion; vm, visceral mass). 186 MIKKELSEN & BIELER branchial chamber just anterior to visceral ganglia (Fig. 29, go). Ova small, approximately 20 вт in diame- ter (maturity not determined, measured in paraffin sections, in posterodorsal region of gonad). Spermatozoa approximately 7 ¡um in head length (acrosome + nucleus + middle piece); nucleus cylindrical, asymetrical; ac- rosome subterminal, dish-shaped with central “papilla,” tilted approximately 45° from long axis of nucleus; middle piece short; tail long. Gametes and gametogenesis to be described in detail in a paper currently in preparation. Brooding large number of small larvae for an undetermined period (longest time ob- served 14 days). Larvae held primarily within outer demibranch, and in suprabranchial chamber where they are circulated via pallial expansions and contractions. During brood- ing, excurrent siphonal opening constricted by sphincter-like muscles around plug formed by free end of rectum (often expanded into bulb by haemocoelic pressure), allowing di- gestive processes to continue during brood- ing and preventing loss of larvae through ex- current siphon. Larvae initially white, turning pink with shell development; released as straight-hinged veligers with apical flagella, 122-138 ¡um in shell length (X = 131.8 um, п = 20; Fig. 17). Larval shell with distinct zone of initial shell formation (Fig. 17, arrow). Lar- vae expelled through excurrent siphon via strong contractions of shell and pallial mus- cles. Adults brooding larvae collected in May and June 1987, and April 1988. Circulatory system: Heart just posterior to umbones, within pericardium lined by brown- ish pericardial gland. Doughnut-shaped ven- tricle traversed by intestine; auricles lateral to ventricle, inconspicuous. Blood vessels not evident; major haemocoelic spaces present within foot, tentacles and main axes of demi- branchs. Excretory system: Kidney yellow, ventralto heart, dorsal to visceral ganglia, surrounding pedal retractor muscles on roof of suprabran- chial chamber. Paired ciliated renopericardial apertures opening anteriorly into ventral wall of pericardium. Paired renal openings into the suprabranchial chamber large, funnel- shaped, adjacent to visceral ganglia. Distribution: Known only from the type lo- cality, Ft. Pierce Inlet, St. Lucie County, and one other location approximately 45 km north, Sebastian Inlet, Brevard County, Florida. Etymology: A noun in apposition from the English vernacular “yo-yo,” a child’s toy orig- inating in China about 1000 B.C., referring here to the periodic up-and-down motion of the bivalve as it hangs from its byssus-thread The word “yo-yo” is in Tagalog, an Indone- sian language, for a similarly constructed, six- teenth-century hunters weapon made of large wooden disks and twine. DIVARISCINTILLA TROGLODYTES, SP. NOV. (FIGS. 2, 4, 7, 12-15, 27). Material examined: Holotype: 7.7 mm [pre- served mantle length], USNM 860038. Para- types (9): 6.7, 4.5 mm, USNM 860039; 6.8, 6.6 mm, MCZ 297407; 7.0, 5.0 mm, IRCZM 064:01722; 4.9, 4.8, 4.5 mm, DMNH 175517. Total material: 87 specimens: FLORIDA: Ft. Pierce Inlet: 10 March 1987, 1; 2-3 May 1987, 12 (including MCZ paratypes); 24 June 1987, 12; 03 August 1987, 4; 14 August 1987, 7; 31 August 1987, 13 (including USNM and IRCZM type specimens); 28 December 1987, 6; 11 March 1988, 6; 12 April 1988, 13. — Sebastian Inlet: 30 December 1987, 13 (in- cluding DMNH paratypes). Type locality. Ft. Pierce Inlet, St. Lucie County, Florida, 27°28.3’N, 80°17.9'W, in Lysiosquilla scabricauda burrows on intertidal sand flats with patches of the seagrass Halodule wrightii Ascherson. Diagnosis Animal translucent yellowish-white. Mantle thin, surface granular with numerous evenly distributed short papillae. Two long “cephalic” tentacles; two short anterior pallial tentacles; three long posterior pallial tentacles surround- ing posterodorsal excurrent siphon. Shell oval, elongate-rounded anteriorly, with weak internal ribs, length approximately 50% of ex- tended mantle length. A single “flower-like organ” on anterior surface of visceral mass ventral to labial palps. Description External features and mantle: Living ex- tended animal (Fig. 2) 10-15 mm in length, globular to oval in general shape, translucent white to yellowish, except for dark upper por- tion of digestive gland showing through tis- BIOLOGY OF DIVARISCINTILLA 187 sues. Shell nearly completely enclosed by rel- atively thin mantle, clearly revealing outlines of shell and ctenidia. Extended mantle some- what posteriorly elongated, with granular sur- face and numerous, evenly distributed, short papillae (Fig. 7, arrows). Anteropedal pallial opening and cowl as in Divariscintilla yoyo. Two long, retractable, “cephalic” tentacles anterodorsally just behind cow!; two shorter, retractable anterior pallial tentacles originat- ing laterally to cephalic pair. Posterodorsal excurrent siphon on prominent rounded pro- tuberance; pallial fusion as in Divariscintilla yoyo. Three long posterior pallial tentacles surrounding excurrent siphon: one anterior and mid-dorsal, two lateral. Umbonal foramen (Fig. 2, uf) a transverse slit-like opening, ca- pable of distention during periods of stress to expose nearly entire shell. Preserved animals with shell nearly com- pletely exposed by retraction of umbonal fo- ramen, retracted pallia! tentacles, contracted cowl and excurrent siphon. Foot often anteri- orly protruding from pallial cavity. Shell (Figs. 12-15). Nearly completely en- closed in chamber formed by pallial layers, communicating with exterior via slit-like um- bonal foramen (Fig. 2, uf). Shell length ap- proximately 50% of relaxed mantle length, ex- tending over dorsal half of visceral mass, and anterior portion of ctenidia. Permanently gap- ing at 80-120° angle while relaxed, incapable of closure more than 50°. Shell (Figs. 12-13) thin, transparent to translucent white except for yellow prodissoconch and network of Opaque white coloration on early portion; equivalve, oval, roundly elongated anteriorly, showing fine growth lines; weak internal ra- dial ribs strongest at periphery, corresponding in placement to weak external grooves. Slightly scalloped edge formed by ends of ra- dial ribs, also evident on former heavier growth lines. Periostracum, hinge (Fig. 14), internal muscle scars (Fig. 4), prodissoconch, and microstructure (Fig. 15) as in Divariscin- tilla yoyo. Organs of the pallial cavity: Foot, visceral mass, and ctenidia as in Divariscintilla yoyo. Labial palps of same general structure as those of D. yoyo, but each with more numer- ous (14-20) lamellae each side. Adductor, pedal, and internal pallial musculature similar to that in D. yoyo. Core muscle bundles of all tentacles continuous with pallial muscle layer; single posterior tentacle receiving muscles from both sides of midline. “Flower-like organ’ (Fig. 27) always single, similar in gen- eral size and form to those of D. yoyo, head with fewer (approximately 25) subunits. Nervous system: As described for Divari- scintilla yoyo. Anterolateral and paired poste- rior tentacles, as well as single posterior ten- tacle receiving innervation from branches of the pallial nerve (Fig. 31, aptn, mptn, pptn). Reproductive system: Simultaneous her- maphrodite. Ovotestis, ova and spermatozoa as in Divariscintilla yoyo. Gametes and game- togenesis to be described in detail in a paper currently in preparation. Divariscintilla troglodytes broods its larvae in the suprabranchial chamber and outer demibranch as in D. yoyo for an undeter- mined period (longest time observed 29 days). Adults brooding larvae were collected in June and December 1987. White larvae with initial stages of shell measured at 68 um diameter. Newly released straight-hinged veligers 120-130 um in length (X = 126.1 шт, п = 20). Digestive, circulatory and excretory sys- tems: As described for Divariscintilla yoyo. Distribution: Same as that of Divariscintilla yoyo. Etymology: A noun in apposition from the Greek rpwyAoövrni = troglodytes, a hole- or cave-dweller. ECOLOGY AND BEHAVIOR Neither Divariscintilla yoyo nor D. troglo- dytes was ever found actually attached to a stomatopod, either in the field or in museum specimens (IRCZM). They are assumed to be free-living within the burrow near the open- ing(s), although specimens were never visible at the opening prior to pumping. However, in spite of other burrowing invertebrates in the area (callianassid shrimps, polychaetes, sip- unculans), neither Divariscintilla species has ever been collected in any habitat other than a Lysiosquilla burrow. The two species were often collected together [and often also with two species of vitrinellid gastropods (Bieler & Mikkelsen, 1988) and two of another galeom- matid genus] from a single Lysiosquilla bur- row (of 21 burrows with Divariscintilla, 12 con- 188 A MIKKELSEN & BIELER Fig. 32. Diagrammatic representation of (А) crawling, (B,C) byssus-thread production, (D) hanging, (E,F) “yoyo” response to stimuli, and (G) crawling to break byssus attachment. tained both, 9 contained only one species). Densities were low, frequently of only one or two specimens per species per burrow sam- ple; the highest number of specimens in one burrow was 13 in the case of either species, and not all burrow samples included galeom- matoideans. However, it must be noted that in no case was an entire stomatopod burrow ex- cavated and assessed for mollusks; the yabby pump only effectively samples its own length (0.5-1.0 m) of the burrow adjacent to an opening. Estimates of occurrence and/or density of any clams living in the deeper hor- izontal section of the burrow was not possible using this method. Small (0.5 mm length) parasitic worms (Trematoda: ?Digenea) were found encased in small tissue pockets on the pallial layer lin- ing the inner shell surface of a specimen of Divariscintilla troglodytes. Density per clam and frequency of occurrence were not as- sessed. Living animals spend much of their time in the laboratory “hanging” from byssus-threads from the water surface, or, more frequently, on the sides of the aquarium or finger bowl. The hanging sequence is depicted in Fig. 32. The byssus-threads (usually two) are pro- duced by the byssus-gland located in the crawling portion of the foot (Fig. 19). Strong pulsing of the byssus-gland area during thread production (Fig. 32, b) is probably caused by engorgement of the many blood spaces in the vicinity; this area remains somewhat swollen for a short time after com- pletion. The threads are attached immediately ‚ to the substrate, usually with a V-shaped at- tachment. As they are completed, the threads appear to be “picked up” (Fig. 32, c) by the byssus adhesive gland at the terminus of the posterior elongation so that they are secured within the ventral groove between the two glands; details of this process are unclear. The “hanging” animal thereafter appears to be suspended from the posterior tip of the foot (Figs. 5; 32, d). While relaxed in this posture, the tentacles and posterior siphon are ex- tended, the ventral edges of the cowl are pursed together forming a functional incurrent siphon, and the crawling portion of the foot is partially withdrawn into the pallial cavity. Pe- riodically, and especially in response to exter- nal stimuli, the adductor muscles, and mus- cles of the mantle, tentacles and foot contract BIOLOGY OF DIVARISCINTILLA 189 simultaneousiy producing rapid movement upward toward the byssus attachment point. This is followed by gradual relaxation and re- turn to the resting/feeding posture. This ac- tion (Fig. 32, e,f) resembles the up-and-down motion produced with a child’s yo-yo toy, and suggested the name for one of the species described here. During normal “hanging,” the posterior foot extension is capable of stretching to a length approximately 1—2 times the mantle length. One specimen of Divariscintilla troglodytes, whose byssus adhesive gland was accidently severed during examination, was able to pro- duce a byssus-thread and hang, although the threads did not lie within the full extent of the ventral groove; the distal half of the posterior extension remained curled at the side of the animal, unextended and unused. These ob- servations lead to the conclusion that the glandular structure at the terminus of the pos- terior foot extension serves to secure the bys- sus-threads within the full length of the ventral groove. It is likely that this gland secretes an adhesive substance for this purpose, there- fore we refer to it here as the “byssus adhe- sive gland.” The fact that the injured animal could still use part of the ventral groove for hanging suggests that the extensive ciliation and mucous secretion of the proximal part of the groove also serve to secure the threads. This specimen was maintained and observed in the laboratory; two weeks after severing the tip of the posterior extension, the animal was observed to be hanging normally and the tip of the foot with its whitish gland had regener- ated and regained function. When dislodged, the clams actively crawl about, using an even, gliding motion pro- duced by ciliary action on the ventral surface of the foot. Sudden contractions of the shell and pallial muscles frequently occur during crawling, and, although not providing any sig- nificant forward propulsion, probably assist the animal in moving its not-so-streamlined body, as well as in cleansing the pallial cavity. The anterior unslit tip of the foot is continually actively “seeking” appropriate substrate. The terminal half of the posterior extension, which is unciliated externally, is not active in crawl- ing, being carried behind either in a trailing curl or with the tip bearly touching the sub- strate behind. The clams were observed to dislodge themselves voluntarily from labora- tory substrate via initiation of crawling activity, thus stretching the byssus-threads until breaking occurred (Fig. 32, g). It is assumed from laboratory observations that the animals spend most of their time in the burrows at- tached to the smoothly packed walls, and that crawling is utilized only when relocation is necessary or when dislodged by external forces. DISCUSSION The two new species described here are remarkably similar to each other in morphol- ogy and behavior. Significant differences are found in shell morphology, the number of “flower-like organs,” and the nature of the mantle, including color, thickness, papillation, and number of pallial tentacles (Table 1). Thus far, both species are known only from the specimens studied and cited here; shells are unknown from dry collections (AMNH, DMNH, IRCZM, USNM), probably because of their fragile nature. The two new species agree closely in anat- omy, habitat, and behavior with those de- scribed for Divariscintilla maoria Powell, 1932, type and sole described species of the genus, by Judd (1971). Some of the features reported here (e.g. stomach, nervous system, reproductive anatomy, shell musculature, cir- culatory and excretory systems) were not dis- cussed for D. maoria, and others (e.g. ctenidia, “flower-like organ,” byssus appara- tus) were described in less detail (Judd, 1971). Differences between our two species and D. maoria in shell, pallial, and perhaps ctenidial characters (see below; Table 1) are weak when weighed against the many simi- larities, and, we accordingly place our new species in Divariscintilla. Shell and musculature: The most distinct difference between the two species described here and the type species of Divariscintilla is in the shape of the shell. Divariscintilla maoria has a ventral notch in each valve, a character used at the generic level (Chavan, 1969) to treat Divariscintilla as a subgenus under Vas- coniella Dall, 1899, whose members possess a likewise-notched shell. The shell of Vas- coniella jeffreysiana (P. Fischer, 1873), the type and sole described species of the genus, however, is greatly inequivalve and notched in only the right valve (Kisch, 1958). As noted by Judd (1971: 344), the ventral notch of Di- variscintilla maoria “does not appear to be functionally important,” as it is not associated with a cleft in the mantle nor with the passage 190 MIKKELSEN & BIELER TABLE 1. Distinguishing characteristics of the three described species of Divariscintilla (for additional information, see text). D. maoria (from Judd, 1971) Shell: General shape oval ventrally notched Prolongation posterior Sculpture unribbed Length relative to mantle length 68% Mantle: Color, thickness (not given) Extent covering shell margins only Papillae very small Anterior tentacles 4 long Posterior tentacles 1 long Defensive appendages 6-8 present Flower-like organs: number 1 Ctenidia: smooth Labial palps: Lamellae per palp (not given) Geographical range: New Zealand of byssus-threads. Therefore, we do not con- sider the presence of this notch a prerequisite to inclusion in Divariscintilla and furthermore do not advocate treatment of Divariscintilla as a subgenus of Vasconiella on this basis. Claims of a “tendency” within the family for the development of a concave or indented ventral shell margin (Powell, 1932; J.E. Mor- ton, 1957) appear overstated; a cursory sur- vey of the galeommatid shells illustrated by Chavan (1969) show that most are evenly rounded at the ventral margin. A second conchological difference between Divariscintilla maoria and the two new spe- cies is the direction of prolongation of the shell. All are skewed, but in opposite direc- tions; D. maoria is prolonged posteriorly while D. yoyo and D. troglodytes are prolonged an- teriorly. Divariscintilla maoria also has a relatively larger shell in relation to its body (maximum shell length approximately 68% of the relaxed mantle length in fig. 1 of Judd, 1971), which also differs by being covered by pallial folds only along its margins. The degree of shell reduction and internalization in members of this superfamily varies widely and is a char- acter which deserves further attention at su- praspecific levels. Divariscintilla yoyo and D. troglodytes both possess the full complement of five major D. yoyo D. troglodytes elongate-pointed oval unnotched unnotched anterior anterior unribbed internal radial ribs 40% 50% whitish, thick yellowish, thin entire entire sparse, very small numerous, small, evenly-distributed 2 long 2 short, 2 long 1 very short 3 long absent absent 3-7 (usually 5) 1 pleated pleated 10-14 14-20 eastern Florida eastern Florida muscles (e.g. two adductors, two pedal re- tractors, and one protractor). As in D. maoria (see Powell, 1932), these leave no muscle scars on the shell, even to the extent, realized during this study, that they do not show under scanning electron microscopy. Mantle ornamentation: The complement of pallial tentacles and papillae is quite different in Divariscintilla maoria and the two new spe- cies described here. The two pairs of anterior tentacles and the single posterior tentacle of D. maoria, described by Judd (1971), seem _homologous to tentacles described in this study. However, D. yoyo and D. troglodytes do not possess anything resembling the “pos- terior appendages” described by Judd (1971). They do, however, possess numer- ous papillae on the exterior portion of the mantle, beyond the shell margins; this area is without papillae in D. maoria. Ctenidia: As shown in Judd (1971: fig. 3) and confirmed here (Fig. 30), the ciliary cur- rents of the ctenidia in Divariscintilla can be ascribed to type C(1) as defined by Atkins (1937). This type, in which only the inner demibranch bears a ventral marginal food groove, is known from a great number of gen- era (e.g., Galeomma: В. Morton, 1973; Сега- tobornia Dall, 1899: Narchi, 1966). Also like BIOLOGY OF DIVARISCINTILLA 191 most other galeommatoideans, the outer demibranch is shorter in Divariscintilla, and interfilamentary junctions are well-developed and numerous. The presence of interlamellar junctions in Divariscintilla (this study; no data available for the type species), contradicting a statement by B. Morton (1973: 142) that the presence of interfilamentary and the /ack of interlamellar junctions “is typical of the Lep- tonacea [ = Galeommatoidea] in general and can be correlated with the habit of incubating their larvae within the ctenidia . . .” (see also B. Morton, 1981: 97-99). Divariscintilla does show, however, a negative correlation be- tween the number of interlamellar junctions and the incubatory habit (see also Oldfield, 1961: 290). In gross morphology, the gills of Divariscin- tila yoyo and D. troglodytes contrast with those of D. maoria and nearly all other ga- leommatoideans in being loosely pleated rather than smooth. This may be an adapta- tion for increasing surface area of the food- gathering structures of animals in habitats (e.g. burrows) that may present reduced food density. Pleating was also observed by Popham (1939) in Phlyctaenachlamys lysio- squillina Popham, 1939, another burrow- dwelling commensal, although it was inter- preted as an artifact due to preservation. Flower-like organs: The function of the “flower-like organs” of Divariscintilla species is not evident, although the presence of glan- dular tissues in the flower head plus the lack of nervous connections point to a secretory rather than sensory role. Judd (1971: 352) de- scribed a single “small median papilla on the dorsal edge of the anterior part” of the vis- ceral mass of D. maoria which is clearly the same structure. No function was suggested by Judd, however, reference to a “mucoid se- cretion” from subepithelial gland cells agrees with this study that the organs are generally secretory. The “flower-like organs’ could possibly emit a pheromone for attracting re- productive partners in conditions of low pop- ulation densities. If so, their placement at the incurrent opening, requiring flow of the attrac- tant through the animal prior to release, is in- deed peculiar. “Flower-like organs” have not been re- ported in any other galeommatoidean genus. However, the pheromone organ and defen- sive papillae of Chlamydoconcha orcutti Dall, 1884 (see B. Morton, 1981), bear at least su- perficial resemblance. They cannot be con- sidered homologous, because the structures described for C. orcutti arise from the middle pallial fold, while Divariscintilla’s “flower-like organs” are from the surface of the visceral mass. Also unlike the organs of C. orcutti, the “flower-like organs” of Divariscintilla are not retractable. Stomach and feeding: The structure of the stomach was not discussed by Judd (1971) in the redescription of Divariscintilla maoria. Stomach structure in the two species de- scribed here agrees well with those of others in this superfamily (e.g. Phlyctaenachlamys Popham, 1939; Galeomma: B. Morton, 1973), defined as type IV by Purchon (1958). Major common features include complete separa- tion of the midgut from the style sac (excep- tions are Pseudopythina P. Fischer, 1884: B. Morton; 1972, and Montacutona Yamamoto & Habe, 1959: B. Morton, 1980), and an arc- shaped major typhlosole leading toward the openings to the digestive diverticula. Varia- tion occurs in the degree of concentration of these latter openings into caeca or ducts, and in the extent of the typhlosole in the midgut. Reproduction: Galeommatoideans are fre- quently cited as having “the most complex reproductive patterns in the Bivalvia” (O Foi- ghil & Gibson, 1984: 72). Hermaphroditism, the occurrence of dwarf or “complemental” males, and ctenidial brooding of larvae are common features of this superfamily and have been claimed to be trends associated with a commensal mode of life (B. Morton, 1976; O Foighil, 1985). No data were pre- sented on the reproductive biology of Divari- scintilla maoria by Judd (1971: 349) other than noting the incubation of larvae in the “ex- halant chamber.” The two Divariscintilla spe- cies described here were both found to brood their young within the folds of the outer demi- branch as well as in the suprabranchial cham- ber. Both species are simultaneous hermaph- rodites. The most unusual reproductive feature encountered was the morphology of the spermatozoa which exhibit rotational asymmetry: the dish-shaped acrosome is tilted approximately 45° from the long axis of the cylindrical nucleus. Foot and locomotion: All galeommatoide- ans are capable of active, snail-like locomo- tion, and most (e.g. Galeomma and Kellia Turton, 1822: Popham, 1940) possess a blunt, heel-like posterior foot with a ventral 192 MIKKELSEN & BIELER groove and a more-or-less postero-terminal byssus-gland. Divariscintilla differs from the typical, but is not unique in having an elon- gated posterior foot; this feature is also present in Phlyctaenachlamys, Rhamphi- donta Bernard, 1975, and Ceratobornia. The foot of Phlyctaenachlamys (Popham, 1939) is nearly identical to that of Divariscintilla, with an elongated posterior portion and a whitish organ at the terminus. In Phlyctaenachlamys, the byssus-gland (although likewise concen- trated in the central portion) continues throughout the posterior extension (Popham, 1939); the “opaque white area immediately short of the tip” of the posterior extension (Popham, 1939: 64) may be similar to the byssus adhesive gland of Divariscintilla, al- though “hanging” behavior has not been de- scribed for Phlyctaenachlamys. The byssus-gland in the elongated poste- rior foot of Rhamphidonta retifera (Dall, 1899) was vaguely described by Bernard (1975) as centrally located; this posterior extension is very different from those discussed above in being dorsoventrally flattened and wider than the anterior portion. “Hanging” behavior was not mentioned by Bernard (1975) for Rham- phidonta. Members of both described species of Cer- atobornia, C. longipes (Stimpson, 1855) and C. cema Narchi, 1966, are capable of hanging from a highly extensible posterior foot; the bys- sus-gland has been described at the extreme posterior tip in both [for С. longipes, see Dall, 1899: 889, pl.88, figs. 10, 11, 13 (previously unpublished figures of Stimpson); for C. cema, see Narchi, 1966: 515, 517-518, text-figs. 2, 5]. However, the byssus apparatus in Cerato- bornia may deserve reinvestigation in light of the structures found in Divariscintilla. Narchi : (1966: 518, fig. 5) provided confusing state- ments about the midventral “main mucous gland” and byssus-gland of Ceratobornia cema, with the latter both at the extreme pos- terior in a text-figure and “extend[ing] along the groove throughout the posterior portion, excepting for the tip” in the text. The “bysso- genus [sic] lamellae” described for the byssus- gland of C. cema bear greater resemblance to Divariscintilla’s byssus adhesive gland than to the byssus-gland proper. Stimpson (1855: 112) reported that, in C. longipes, “there is no true byssus” although a “glutinous substance” secreted by the “opaque byssal gland” at the posterior terminus “may be slightly drawn out”; this material was re-interpreted by Dall (1899: 889) as a “single byssal thread.” In Divariscintilla maoria, the white organ at the end of the posterior extension was inter- preted as the byssus-gland, secreting a single thread by which the animal “hangs.” In view of the present interpretation of the foot of the two new species, this seems in need of re- investigation. The members of Divariscintilla, Phlyctaen- achlamys, and Ceratobornia have all been described as inhabiting the holes of burrowing invertebrates (Stimpson, 1855; Popham, 1939; Narchi, 1966); although the location of the byssus-gland apparently differs, the ability to hang from an extensible, thread-like foot may be an advantage in attachment to verti- cal walls. [However, other galeommatoideans that lack this feature also inhabit holes, e.g. three species referrable to Scintilla De- shayes, 1856, from these same Lysiosquilla burrows (Mikkelsen & Bieler, pers. obs.).] Ceratobornia cema was also reported to at- tach “temporarily to the body of the shrimp [Callianassa major Say]” (Narchi, 1966: 522), although details of this attachment were not given. The byssus apparatus of Kellia suborbicu- laris (Montague, 1803) and of Montacuta sub- striata (Montagu, 1808) described by Oldfield (1961: 269-270, figs. 5, 7), each consist of a “subsidiary” byssus-gland dorsal to the ven- tral groove of the foot, plus a “main” byssus- gland with “byssogenous lamellae” equipped with a duct to the posterior “heel.” These bear superficial resemblance to the foot of Divari- scintilla, but need behavioral observations and more detailed histological examination for proper comparison. The supportive “chondroid wedge” de- scribed for Ceratobornia cema, Rhamphi- donta retifera, and several other galeomma- toideans (Narchi, 1966; Bernard, 1975) is not present in Divariscintilla. Although extremely similar in gross mor- phology, the anterior foot of Divariscintilla is not the “compact mass of muscle” described for Phlyctaenachlamys by Popham (1939). Longitudinal muscle fibers are sparse in the anterior foot of Divariscintilla, being more con- centrated in the posterior extension. Exten- sion of the anterior tip is apparently accom- plished by haemocoelic pressure. The crawling activity of many galeomma- toideans (e.g. Montacuta Turton, 1822: Gage, 1968a; Mysella Angas, 1877: Gage, 1968b) has been described roughly as an extend-at- tach-pull forward sequence. Divariscintilla, in contrast, relies primarily on ciliary action for BIOLOGY OF DIVARISCINTILLA 193 forward crawling movement. Propulsive shell and pallial muscle contractions assist locomo- tion in Phlyctaenachlamys (Popham, 1939) and Galeomma (B. Morton, 1973), and at least to some extent in Divariscintilla. During these contractions in Divariscintilla, the rela- tively large adductor muscles partially close the shell, reducing the shell angle by about 50%. This is in contrast to the “poorly devel- oped” adductor muscles of Phlyctaenach- lamys, contraction of which causes “little movement of the shell valves” (Popham, 1939: 67). Retention of well-developed ad- ductor muscles in Divariscintilla may have been favored by providing additional water- propelling force for locomotion and cleansing of the pallial cavity. Commensalism: The nature of the associ- ation between these bivalves and their sto- matopod “host” is unclear. Although appar- ently more dependent upon the burrow habitat than on the resident stomatopod, col- lection records suggest a strongly obligatory association with Lysiosquilla for both new Di- variscintilla species. The large-diameter bur- rows of this particular stomatopod, with their smooth, hard-packed walls, are well suited for byssus attachment by the clams and provide a well-maintained, protective habitat. Further- more, strong respiratory currents produced in the burrow by the stomatopod are undoubt- edly beneficial to these more-or-less con- fined, filter-feeding clams. Ockelmann & Muus (1978) have suggested that this type of association is dependent upon the bivalves’ responses to chemical/host, rather than phys- ical, stimuli. Indeed, neither Divariscintilla species described here has ever been found in any other habitat, protective or otherwise. Redescription of the genus: This work re- defines Divariscintilla and identifies the fol- lowing generic characters: Shell thin, pro- longed anteriorly or posteriorly, incompletely internalized within pallial tissues; hinge teeth reduced, possessing only small cone-shaped cardinals. Mantle ornamented with species- specific numbers of tentacles and papillae. Byssus-gland communicating by ventral groove with posterior byssus adhesive gland. Two-part foot, consisting of extensible ante- rior crawling portion and tubular posterior extension, used in active crawling and “hanging.” Secretory “flower-like organs” on anterior surface of visceral mass, situated ventral to labial palps. Eulamellibranch ctenidia with interlamellar and interfilamen- tary junctions. Simultaneous hermaphroditic reproduction with ctendial incubation of lar- vae. The known range of the genus is extended from New Zealand alone (type species, Di- variscintilla maoria) into the western Atlantic (D. yoyo and D. troglodytes, described here). ACKNOWLEDGMENTS The following are gratefully acknowledged: Dr. Raymond B. Manning (USNM), for bring- ing this interesting fauna to our attention: William D. (“Woody”) Lee (SMSLP), for in- valuable field help; Patricia A. Linley (HBOI) for SEM assistance and preparation of the sections in Fig. 23; Julianne Piraino (SMSLP) for SEM assistance; Tom Smoyer (HBOl) for photographic work; Dr. Kerry B. Clark (Florida Institute of Technology, Melbourne) and John Е. Miller (HBOI) for the use of and help with video recording equipment; Dr. R. Tucker Ab- bott for literature; Solene Morris [British Mu- seum (Natural History)] for the loan of perti- nent museum specimens; Drs. Richard S. Houbrick (USNM), Kenneth J. Boss (MCZ), and one anonymous reviewer for valuable comments on the manuscript. This research was supported in part by the Smithsonian Marine Station at Link Port; the cooperation of Dr. Mary E. Rice and her team is gratefully acknowledged. Funding for this project was derived in part from a National Capital Shell Club scholarship to P.M., and a NATO Postdoctoral Fellowship at SMSLP to R.B. (administered by the German Academic Exchange Service [Deutscher Akademischer Austauschdienst (DAAD)], Bonn). This is Har- bor Branch Oceanographic Institution Contri- bution no. 704 and Smithsonian Marine Sta- tion Contribution no. 237. LITERATURE CITED ABBOTT, В. 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GIBSON, 1984, The morphol- оду, reproduction and ecology of the commensal bivalve Scintillona bellerophon spec. nov. (Ga- leommatacea). The Veliger, 27(1): 72-70. OLDFIELD, E., 1961, The functional morphology of Kellia suborbicularis (Montagu), Montacuta fer- ruginosa (Montagu) and M. substriata (Montagu), (Mollusca, Lamellibranchiata). Proceedings of the Malacological Society of London, 34: 255— 295. РОРНАМ, М. L., 1939, On Phlyctaenachlamys Iysiosquillina gen. and sp. nov., a lamellibranch commensal in the burrows of Lysiosquilla macu- lata. British Museum (Natural History), Great Bar- rier Reef Expedition 1928-29, Scientific Reports, 6(2): 61-84. POPHAM, М. L., 1940, The mantle cavity of some of the Erycinidae, Montacutidae and Galeomma- tidae with special reference to the ciliary mecha- nisms. Journal of the Marine Biological Associa- tion of the United Kingdom, 24(2): 549-587. POWELL, A. W. B., 1932, On some New Zealand pelecypods. Proceedings of the Malacological Society of London, 20(pt. 1): 65-72, pl. 6. PURCHON, R. D., 1958, The stomach in the Eu- BIOLOGY OF DIVARISCINTILLA 195 lamellibranchia: stomach Type IV. Journal of Zo- ology (London), 131: 487-525. RICHARDSON, К. С., L. JARRETT, & Е. H. FINKE, 1960, Embedding in epoxy resins for ultra-thin sectioning in electron microscopy. Stain Technol- ogy, 35: 313-323. ЗТАЗЕК, С. R., 1964, Synopsis and discussion of | the association of ctenidia and labial palps in the bivalved Mollusca. The Veliger, 6: 91-97. STIMPSON, W., 1855, On some remarkable ma- rine Invertebrata inhabiting the shores of South Carolina. Proceedings of the Boston Society of Natural History, 5: 110-117. THIELE, J., 1934, Handbuch der Systematischen Weichtierkunde, Teil 3. G. Fischer, Jena, 779- 1022 pp. TRYON, G. W., JR., 1872, Catalogue and synon- ymy of the family Galeommidae. Proceedings of the Academy of Natural Sciences of Philadel- phia, 1872: 222-226. VOKES, H. E., 1980, Genera of the Bivalvia: a sys- tematic and bibliographic catalogue (revised and updated). Paleontological Research Institution, Ithaca, New York, xxvii + 307 pp. Revised Ms. accepted 18 April 1989 ern ; wai DAT oe de ve va 14574. UP Ta : a 4 14 ile “ag ПА (ee ars 7 o u 12 Bete i Ss == у . af 2 4 д Pú ni Ve ©" + | | . D : . en u a 1 А | u | de | SD de 1 ММ ta $ on E = ' u a ‘т TM A o E u vi 2 y L > Ve 7 о o Е 4 o = . - o i 1 = 0 | e 4 >. ‘=! = 3 ce. : - Br q Е o o ws x i = Ю o у y i = р o Ha = = 7 т в u e WA - у | = > ~ у я ni a L 5 | ae : | ÉS = ый nl { é { i т im + resent Mim DIN о oft MALACOLOGIA, 1989, 31(1): 197-203 KARYOTYPIC EVOLUTION IN PLEUROCERID SNAILS. I. GENOMIC DNA ESTIMATED BY FLOW CYTOMETRY Robert T. Dillon, Jr. Department of Biology College of Charleston Charleston, South Carolina, U.S.A. 29424 ABSTRACT Total genomic DNA was measured in 16 species of North American pleurocerids, representing all six living genera. A constant value of 2.1 pg DNA/haploid genome was obtained, consistent with values from other mesogastropoods and other mollusks with similar chromosome number. The relationship between DNA content and evolutionary radiation is called into question. Key words: Snails, freshwater, Pleuroceridae, cytogenetics, flow cytometry, DNA. INTRODUCTION Few groups of North American mollusks are as common, diverse, important, or poorly understood as the pleurocerid snails. They are the most conspicuous element of the macrobenthos in many rivers and streams, and as such have figured prominently in a number of ecological investigations (e.g. El- wood & Nelson, 1972; Sumner & Mclintire, 1982; Hawkins & Furnish, 1987; Dillon & Davis, in review). Their occurrence in numer- ous, isolated populations, easily sampled year round, has made them ideal models for evolutionary research (Chambers, 1980, 1982; Dillon, 1984, 1988a, 1988b). Yet their systematics are so confused that the specific identity of the populations inhabiting much of the United States is problematic. The first monographic treatment of the fam- ily was given by Tryon (1873). He catalogued about 500 nominal species, which he placed in nine genera. The currently accepted sys- tem of classification is due to a series of pa- pers by Goodrich (e.g. 1940, 1942). Goodrich recognized somewhat over 100 species and subspecies, and his revision formed the basis of the classification by Burch & Tottenham (1980) and Burch (1982) that | use here. Burch recognized six living genera: lo, Juga, Leptoxis (including Goodrich’s Anculosa, Ni- tocris, and Eurycaelon), Lithasia, Pleurocera, and Elimia. Burch resurrected “Elimia” on the strength of Pilsbry & Rhoads’ (1896) type designation, failing to note that Pilsbry subse- quently reversed himself (Walker, 1918:149). 197 Elimia is a composite group, and thus | use the much more familiar name favored by Tryon and Goodrich, Goniobasis. Very little distinguishes many of these gen- era. Pleurocera is distinguished from Gon- iobasis by a short “canal” on the anterior lip of the shell, a feature that is inconspicuous ог absent in many species. Detailed compari- sons of morphology, anatomy, life history, and ecology failed to find any other distinc- tions (Dazo, 1965). Juga is distinguished from Goniobasis by being from western North America, not eastern or central. It seems clear that the systematic relationships of pleu- rocerid snails need to be re-examined. Analysis of karyotype has proven to be a powerful tool in evolutionary studies (White, 1973). But very little is known about the cyto- genetics of any pleurocerid species. In a re- view of molluscan karyotypes, Patterson (1969) found two reports for North American pleurocerids: n = 18 for Goniobasis laqueata and n = 20 for G. livescens. Dillon (1982) reported п = 17 in G. proxima. The most thor- ough study to date has been made by Cham- bers (1982), who found n = 18 in Florida Go- niobasis and described striking variation in arm length ratios. So the evidence available suggests that karyotypic variation does occur in the Pleuroceridae. In this series of papers, | will survey the six genera to see whether karyotype may be used to elucidate the sys- tematics and evolution of this important family of freshwater snails. Karyotypes are traditionally compared by constructing idiograms for each species, re- 198 DILLON producing the relative sizes and centromeric positions of the chromosomes. Idiograms are generally standardized to unit length, so that each species is assumed to have the same amount of genetic material. An increase in chromosome number is viewed as a centric fission. This is a reasonable assumption— many convincing examples of such “Robert- sonian” events are known. But an increase in chromosome number could also represent additional genetic material. Additional chro- mosomes may be incorporated into agenome by coincident nondisjunction in the parents, or by large-scale gene duplication (Ohno, 1970). Thus it is of great value to determine the total genomic DNA content of each species to be karyotyped. In this first paper of the series, | estimate the genomic DNA content of a vari- ety of pleurocerid snails using flow cytometry. Flow cytometry is one of the most sensitive techniques available for quantifying cellular DNA. The technique has been used to dis- criminate between human chromosomes (Gray et al., 1975) and identify structural ab- normalities in the chromosome compliments of cell lines (review by Arkesteijn et al., 1987). The technique has been thoroughly reviewed by Melamed et al. (1979), Van Dilla et al. (1985), and Shapiro (1988). Briefly, tissues in an aqueous suspension are stained with a dye that intercalates into double-stranded nucleic acid. | used propid- ium iodide, after treatment with ribonuclease to eliminate double-stranded RNA. Then the suspension is channeled at high speed through a narrow aperture, using mechanics similar to those of the familiar Coulter counter. Each individual particle passes through a la- ser, which excites a red-fluorescent emission proportional to its DNA content. The degree to which the laser beam is scattered by each particle provides an estimate of the particle’s size. The emissions of the individual particles are captured by photosensors and displayed in a scatter plot, which enables the operator to distinguish individual, whole cells from debris and clumped cells. Then the red fluorescence of the whole-cell fraction is plotted in a histo- gram, with fluorescence measured in arbi- trary units called “channel numbers.” Since the relationship between channel number and DNA content is effectively linear, a flow cy- tometer calibrated with known samples can be used to estimate the DNA content of an unknown. The contribution of mitochondrial DNA to total red fluorescence has generally been found to be negligible (Melamed et al., 1979). Correction for any background mtDNA levels can be made by using a single tissue type for both the unknowns and the calibration stan- dards. METHODS The following populations were sampled: Goniobasis acutocarinata (Lea)—Small creek flowing into the Powell River at Virginia Highway 662 bridge, 0.5 km E of Stickeys, Lee County, Virginia. Goodrich (1940) synon- ymized this species under G. clavaeformis (Lea). Goniobasis alabamensis (Lea)—Coosa River at tailwater of Mitchell Dam, 20 km Е of Clanton, Chilton County, Alabama. Goniobasis catenaria dislocata (Reeve)— “Intermittent” tributary of Big Poplar Creek at South Carolina Highway 6 bridge, 3 km SE of Elloree, Orangeburg County, South Carolina. Goniobasis floridensis (Reeve)—Blue Spring at Florida Highway 6, Madison County, Florida. Site 8 of Chambers (1980). Goniobasis livescens (Menke)—Portage Creek at Toma Road bridge, 5 km S of Pinck- ney, Washtenaw/Livingston County line, Mi- chigan. Station 2 of Dazo (1965). Goniobasis proxima (Say)—Mitchell River at North Carolina Highway 1330 bridge, 2.8 km N of Mountain Park, Surrey County, North Carolina. Site MTCH of Dillon (1982, 1984). Goniobasis simplex (Say)—same site as G. acutocarinata. lo fluvialis (Say)—Powell River by small road just S of Virginia line, Hancock County, Tennessee. Juga hemphilli (Henderson)—Oak Creek ‚ 11 km W of Corvallis, Benton County, Ore- gon. Leptoxis (Mudalia) carinata (Brug.)—Pratts Run at U.S. Highway 340 bridge, Waynes- boro, Augusta County, Virginia. Leptoxis praerosa (Say—same site as lo fluvialis. Lithasia duttoniana (Lea)—Duck River at Tennessee Highway 11 bridge, 10 km N of Farmington, Marshall County, Tennessee. Lithasia verrucosa (Raf.)—French Broad River at Cement Shoals, 1 km downstream from Kimberlin Heights, Knox County, Ten- nessee. Pleurocera acuta Raf.—Dazo's (1965) sta- tion 2, same as G. livescens. Pleurocera canaliculatum (Say)—Elk River DNA IN PLEUROCERIDS 199 1cm FIG. 1. From left, Lithasia duttoniana, Goniobasis catenaria dislocata, G. alabamensis, G. acutocarinata, Juga hemphilli. at bridge 8 km W of Fayetteville, Lincoln County, Tennessee. Pleurocera unciale (Reeve)—same site as lo fluvialis. The shell morphology of many of these species is quite variable, as are the species concepts of many prior workers in pleurocerid taxonomy. Typical shells from several of the less common taxa are shown in Fig. 1. Voucher specimens for all populations are de- posited in the Academy of Natural Sciences of Philadelphia. Techniques for sample preparation were based on Allen (1983), Buzzi (1989), and standard clinical methods. Foot muscle was excised from living snails and ground, with powdered glass, in a clear polystyrene tube with 600 ul of phosphate buffered saline. This buffer was modified from Allen (1983): NaCl 8.0 g/l, KCI 0.20 g/l, MgCl; 0.10 g/l, Nas HPO, 1.15 g/l, KH2PO, 0.20 g/l. Drops of cold ab- solute ethanol were added, while vortexing, to bring the final ethanol concentration up to 70%. Samples fixed in this manner were held at least overnight at 3°C, and sometimes as long as two weeks. An RNAse solution was prepared by dis- solving 50 mg ribonuclease A (Sigma type IIl- A) in 50 ml 1.12% trisodium citrate and heat- ing at 80°C for 10 minutes. The solution was frozen in 2 ml aliquots. On the morning of flow cytometric analysis, fixed tissue samples were centrifuged, aspirated, and resuspend- ed in a several ml of a solution containing 47 ml phosphate buffered saline, 1 ml 1.2% (v/v) Nonidet P-40, and one aliquot of RNAse so- lution. Since the lot of ribonuclease III-A that | received had 105 units of activity per ml, the final RNAse activity in phosphate buffered sa- line was approximately 4 units/ml. Tubes were incubated at room temperature for 30— 60 minutes. Each sample was vortexed, drawn into a 1 ml tuberculin syringe, and forced through a 52 шт Nytex screen. Then 20 ul of a 0.10% (w/v) propidium iodide solution was added per ml of tissue Suspension, and incubated at room temperature for 30-60 minutes prior to anal- ysis on an Ortho Spectrum III flow cytometer. In collaboration with W. Buzzi, a calibration curve was constructed using human leuko- cytes and tissue samples from four mollusk species of known genomic content. We anal- ysed four Crassostrea virginica (Gmelin), five Mercenaria mercenaria (L.), and two Ilyan- assa obsoleta (Say), all collected from the Charleston, South Carolina, area. We ob- tained four Mytilus edulis L. from Milford, Con- necticut. The total genomic DNA of C. virgin- ica is given by Swanson et al. (1981:134), and values for the remaining mollusks are from Hinegardner (1974). Three individuals of G. catenaria dislocata were included as un- knowns. Goniobasis catenaria dislocata served as the standard in all subsequent analyses. Sev- eral fresh G. catenaria were analysed first, followed by four to six individuals of a second pleurocerid species. The peak red fluores- cence for each sample was noted, as well as the concentration of countable cells. Aliquots from samples of the two species were com- bined into a third tube such that cell concen- trations were equalized. The combined sam- ple was then re-analysed and the resulting histogram of red fluorescence inspected for 200 DILLON Relative Fluorescence 1.0 0 0.5 1.9 2.0... 2.5 ЗО ра ОМА / haploid genome FIG. 2. Calibration curve. O—Crassostrea, M—Mytilus, C—Mercenaria, G—Goniobasis саепапа dislocata, H—human, I—/Iyanassa. evidence that the two peaks were non-over- lapping. RESULTS The calibration curve is shown in Fig. 2. An excellent fit to the linear hypothesis y = 10.8x — 3.76 was obtained, with г? = 0.98. So given a mean relative fluorescence of 17.3, | estimated that G. catenaria dislocata has 2.1 ра DNA/haploid genome. A typical comparison between G. catenaria dislocata and an unknown (G. proxima in this case) is shown in Fig. 3. This particular sam- ple of G. catenaria tissue came from a snail collected the previous day, and shows two peaks—a strong gap 1 peak and a lower gap 2/mitosis peak with twice the fluorescence. Only snails freshly collected in warm weather generally showed a gap 2 peak. Even if tem- perature and photoperiod were controlled and the snails fed commercial fish food ad lib, gap 2 peaks generally disappeared after only a day or so in captivity, as shown in the G. prox- ima sample. In fact, it is evident that DNA synthesis has already been discontinued in the G. catenaria individual analysed, since no S-phase cells, with DNA contents intermedi- ate between G1 and G2, are apparent in Fig- ure 3. So although the snails in my aquaria always appeared healthy, cell division in foot DNA IN PLEUROCERIDS 201 muscle tissue was apparently disrupted al- most immediately. The rapid loss of cells at gap 2 and mitosis in captive snails did not affect the accuracy of sample comparisons. The much stronger, sharper gap 1 peaks were used as the basis for comparison in all cases. No difference was detected between the peak red fluorescence of G. catenaria dislo- cata and that observed in any other species of pleurocerid examined. Figure 3 shows that an equal mixture of G. catenaria cells and G. proxima cells shows no evidence of two gap 1 peaks. This result was obtained in all compar- isons. DISCUSSION К would appear that all 16 pleurocerid spe- cies in my sample, representing six genera, have a uniform genomic DNA content of 2.1 pg DNA/haploid genome. Hinegardner (1974) found that seven species of mesogastropods range from 0.67-2.4 pg DNA/haploid ge- nome. A vermetid was the only cerithiacean examined, with 1.5 pg DNA/haploid genome. So the value | have obtained for pleurocerids is consistent. From a broad comparison of gastropod or- ders, Hinegardner suggested that high amounts of DNA appear to be associated with evolutionary radiation. But in spite of their rather average-sized genome, the Pleurocer- idae have radiated extensively. Hinegardner's generalization may not hold for freshwater groups, where dispersal is generally much more restricted and the poiential for differen- tiation greater. Across the five kingdoms, there is a general relationship between genome size and de- gree of organismal complexity or “evolu- tionary advancement” (Hinegardner, 1976). The “C-value paradox” arose when it was noted that some organisms, such as some flowering plants and amphibians, have amounts of DNA (“C-values”) much greater than more advanced eukaryotes. But the pleurocerid genome size is rather typical for mollusks, and for invertebrates in general. Hinegardner (1974) reported a correlation between chromosome number and DNA con- tent in gastropods significant at the 0.01 level. Extrapolating from his graph, a chromosome number of n = 13 to 18 would be predicted from the DNA content of North American pleurocerids. This is consistent with the lim- 1000 500 1000 500 Cell Count 1000 500 0 100 200 Fluorescence FIG. 3. Example comparison of unknown and stan- dard. Top—fresh G. catenaria dislocata standard, showing gap 1 and gap 2 peaks. Middle—the un- known (G. proxima), showing gap 1 peak only. Bot- tom—equal mixture of standard and unknown, demonstrating complete overlap of gap 1 peaks. ited information available on pleurocerid kary- otypes. Ongoing studies will more thoroughly address the degree to which uniformity in ge- nomic DNA content reflects karyotypic con- servation in this family. Any variation in chro- mosome number among pleurocerids can be 202 DILLON viewed with some confidence as originating in Robertsonian fusion or fission. ACKNOWLEDGMENTS | thank Dr. Fred Thompson, Dr. Gary Lam- berti, and Randy Wildman for providing spec- imens; Steve Ahlstedt for locality data; and John Wise and Robert T. Dillon, Sr., for help with the collecting. Dr. Mariano LaVia was a gracious host at the Medical University of South Carolina's flow cytometry unit, and Jo Ann Koffskey provided expert technical assis- tance. Special appreciation is due to Bill Buzzi, who worked out most of these tech- niques and shared them with me. LITERATURE CITED ALLEN, 5. K., 1983, Flow cytometry: assaying ex- perimental polyploid fish and shellfish. Aquacul- ture, 33:317-328. АВКЕЗТЕММ, С. J. A., А. С. М. MARTENS, В. В. JONKER, А. HAGEMEIJER, & А. HAGENBEEK, 1987, Bivariate flow karyotyping of acute myelo- cytic leukemia in the BNML rat model. Cytometry, 8:618—624. BURCH, J. B., 1982, North American freshwater snails: identification keys, generic synonymy, supplemental notes, glossary, references, index. Walkerana, 4:1-365. BURCH, J. B., & J. L. TOTTENHAM, 1980, North American freshwater snails: species list, ranges, and illustrations. Walkerana, 3:1-215. BUZZI, W., 1989, Growth and survival of larval and juvenile polyploid clams, Mercenaria mercenaria. MS thesis, College of Charleston, SC. CHAMBERS, S. M., 1980, Genetic divergence be- tween populations of Goniobasis occupying dif- ferent drainage systems. Malacologia, 20: 63— 81. CHAMBERS, S. M., 1982, Chromosonal evidence for parallel evolution of shell sculpture pattern in Goniobasis. Evolution, 36:113-120. DAZO, B. C., 1965, The morphology and natural history of Pleurocera acuta and Goniobasis livescens (Gastropoda: Cerithiacea: Pleurocer- idae). Malacologia, 3:1-80. DILLON, В. T., Jr., 1982, The correlates of diver- gence in isolated populations of the freshwater snail, Goniobasis proxima. Ph.D. dissertation, University of Pennsylvania, Philadelphia. 183 pp. DILLON, В. T., Jr., 1984, Geographic distance, en- vironmental difference, and divergence between isolated populations. Systematic Zoology, 33: 69-82. DILLON, R. T., Jr., 1988a, The influence of minor human disturbance on biochemical variation in a population of freshwater snails. Biological Con- servation, 43:137-144. DILLON, R. T., Jr., 1988b, Evolution from trans- plants between genetically distinct populations of freshwater snails. Genetica, 76:111-119. DILLON, В. T., Jr., & К. В. DAVIS, In review, The diatoms ingested by freshwater snails: temporal, spatial, and interspecific variation. ELWOOD, J. W., & D. J. NELSON, 1972, Periphy- ton production and grazing rates in a stream measured with a 92P material balance method. Oikos, 23:295—303. GOODRICH, C., 1940, The Pleuroceridae of the Ohio River system. Occasional Papers of the Mu- seum of Zoology, University of Michigan, no. 417: 21 pp. GOODRICH, C., 1942, The Pleuroceridae of the Atlantic coastal plain. Occasional Papers of the Museum of Zoology, University of Michigan, no. 456:6 pp. GRAY, J. W., A. V. CARRANO, L. L. STEINMETZ, M. A. VANDILLA, D. H. MOORE, B. H. MAYALL, 8 М. L. MENDELSOHN, 1975, Chromosome measurement and sorting by flow systems. Pro- ceedings of the National Academy of Science, 72:1231-1234. HAWKINS, С. P., & J. К. FURNISH, 1987, Are snails important competitors in stream ecosys- tems? Oikos, 49:209-220. HINEGARDNER, R., 1974, Cellular DNA content of the Mollusca. Comparative Biochemistry and Physiology, 47A:447—460. HINEGARDNER, R., 1976, Evolution of genome size. In Molecular evolution, AYALA, F. J., ed. Sinauer Associates, Sunderland, Mass, pp. 179— 199. MELAMED, М. R., Р.Е. MULLANEY, & М. L. MEN- DELSOHN, eds., 1979, Flow cytometry and sort- ing. John Wiley & Sons, N.Y. 716 pp. OHNO, S., 1970, Evolution by gene duplication. Springer-Verlag, NY. 160 pp. PATTERSON, C. M., 1969, Chromosomes of mol- luscs. In Proceedings of the Symposium on Mol- lusca, Part Il. Marine Biological Association of India. Bangalore Press, Bangalore, India. pp. 635—686. PILSBRY, Н. A., & 5. М. RHOADS, 1896, Contri- butions to the Zoology of Tennessee, No. 4, Mol- lusca. Proceedings of the Academy of Natural Sciences of Philadelphia, 1896:487-506. SHAPIRO, H. M., 1988, Practical flow cytometry, 2nd ed. A. R. Liss, NY. 353 pp. SUMNER, W. T., & С. D. MCINTIRE, 1982, Grazer- periphyton interactions in laboratory streams. Ar- chiv fur Hydrobiologie, 93:135-—157. SWANSON, C. P., T. MEVE, & W. J. YOUNG, 1981, Cytogenetics: the chromosome in division, inheritance, and evolution, 2nd ed. Prentice Hall, Englewood Cliffs, NJ. TRYON, G. W., Jr., 1873, Land and freshwater shells of North America. Part IV. Strepomatidae. Smithsonian Miscellaneous Collections. no. 253: 435 pp. DNA IN PLEUROCERIDS 203 VAN DILLA, M. A., Р. М. DEAN, О. D. LAERUM, & of Zoology Miscellaneous Publications No. 6:213 M. R. MELAMED, eds., 1985, Flow cytometry: рр. instrumentation and data analysis. Academic WHITE, M. J. D., 1973, Animal cytology and evo- Press, Orlando, FL. 288 pp. lution, 3rd ed. Cambridge University Press, Lon- WALKER, B., 1918, A synopsis of the classification don. of the freshwater Mollusca of North America, north of Mexico. University of Michigan Museum Revised Ms. accepted 12 March 1989 MALACOLOGIA, 1989, 31(1): 205-210 HABITAT SELECTION BY A FRESHWATER MUSSEL: AN EXPERIMENTAL TEST Robert C. Bailey Ecology and Evolution Group Department of Zoology University of Western Ontario London, Ontario, Canada N6A 5B7 ABSTRACT Two groups of the freshwater mussel Lampsilis radiata siliquoidea (Barnes, 1823) were col- lected in Inner Long Point Bay, Lake Erie. The first group of mussels was collected from sandy, turbulent areas of the bay, while the second group was collected from soft-bottomed, muddy areas. The sand-collected mussels were larger and thicker-shelled than the mud-collected group, which is consistent with previously observed correlations between shell form and habitat in this and other Unionidae species. | placed 50 individuals from each of these two groups into each of two artificial ponds. Each pond contained equal areas of sand and mud in “checker- board” fashion, and each mussel was placed at random coordinates on the bottom of the ponds. After four months, two-thirds of the mussels were found in the mud sedimeni. About 80% of the mussels initially placed in mud stayed there, while about half of the mussels initially placed in sand moved to mud. Sand-collected mussels had a stronger tendency, relative to the mud- collected group, to either stay in mud if they started there or move to mud from sand. The results support the hypothesis that habitat selection has evolved in this unionid species, but are not consistent with the hypothesis that the two groups of mussels represent specialists for the habitats from which they were collected. Key words: habitat selection; Unionidae; shell morphology; specialists; sediment preference. INTRODUCTION As discussed by both Kat (1982) and Hueh- ner (1987), there has been more observa- tional and anecdotal evidence than detailed, experimental study of habitat selection in freshwater mussels. This has lead to a re- markable lack of understanding of their ability (or lack of ability) to select habitat. Clearly this knowledge is important in understanding the relative niche breadths of each species, as well as the degree of niche overlap among species. Short-term (three-hour) experiments in the laboratory by Huehner (1987) indicated that most populations of Anodonta grandis Say, 1829, and Lampsilis radiata (Gmelin, 1791) show a preference for sand over gravel. The other species tested, Elliptio dilatata (Ra- finesque, 1820), showed no substrate prefer- ence. Huehner (1987) commented on the be- havioural and morphological plasticity of Lampsilis radiata. In his laboratory experi- ments, one population of L. radiata sili- 205 quoidea showed a preference for sand, while another had no preference. In this study, | tested the ability of two Lampsilis radiata sil- iquoidea forms to select substrate over a rel- atively long (four-month) experimental period. Lampsilis radiata siliquoidea (Barnes, 1823) is one of many freshwater mussels whose shell morphology and growth rate vary with habitat. Bailey & Green (1988) and Hinch et al. (1986) found thicker-shelled, faster- growing L. г. siliquoidea in the turbulent, sandy sediment areas of Inner Long Point Bay, Lake Erie, when compared to conspe- cific mussels from the more quiescent, muddy areas of the bay. Many authors have claimed that correlations between the habitat of fresh- water mussels and their shell form are due to differential adaptation resulting in specialist phenotypes. Wilson & Clark (1914) sug- gested that larger, flatter shell forms are bet- ter adapted to burrowing in the coarse sub- strates of fast current areas in streams, while smaller, more obese (large width-to-length ra- tio) shells maintain a mussel’s buoyancy in 206 BAILEY 100 80 60 40 Percent Finer 20 0.001 0.01 0.1 1 Grain Size (mm) FIG. 1. Particle size distribution of substrates used in the pond experiment (- - - - SAND, ——- MUD). soft substrates. Eagar (1978) claimed that more obese shells allow for a greater volume of soft tissue, thereby improving the “meta- bolic and functional activity” of mussels in qui- eter waters. Stanley (1970) considered the functional morphology of the entire Class Bi- valvia and drew conclusions similar to those of Wilson & Clark (1914). Although these hy- potheses seem reasonable, clear tests of their predictions have not been made. In the present study, L. г. siliquoidea from both turbulent and quiescent areas of Inner Long Point Bay, Lake Erie, were used in a substrate selection experiment carried out in artificial ponds. Mussels from the two areas differed morphologically in a manner more or less consistent with the adaptive hypotheses outlined above. | predicted that if these two phenotypes represented specialists for differ- ent habitats, the availability of both fine- and coarse-grained sediments in artificial ponds would lead to differential habitat selection by the two groups of mussels. MATERIALS AND METHODS Оп 11 June 1985, 100 similarly aged (8— 12-year-old) L. г. siliquoidea were collected using SCUBA from each of low and high ex- posure areas in Inner Long Point Bay, Lake Erie. Inner Long Point Bay is a large (75 km?), shallow (z = 2.5 m) bay with a heteroge- neous distribution of high, medium, and low exposure areas grading into one another (see Bailey, 1988, for a map of exposure areas). The mussels were collected from well within one high and one low exposure area in the bay, in each case within 50 m of the boat. These mussels were transplanted into two ar- tificial ponds on the campus of The University of Western Ontario. Each pond measured 5 x 9 m and had a depth of about one meter. One week before collecting the mussels, equal areas of “sand” and “mud” sediment, obtained from Southwinds Sand and Gravel (London, Ontario), were spread to a depth of about 15 cm prior to filling the ponds with city water using taps located at the side of each pond. The sediment was added in checker- board fashion such that there were two rect- angular areas of each sediment in each of the ponds. The sand used was “golf course sand”; the mud was from silt deposits created by the wastewater from washing crushed gravel. Percent loss on ignition, determined as described in Bailey (1988), was nil for both substrates. Particle size analysis, using wet sieving and hygrometer analysis (Bowles, 1978), indicate that the mud was finer and more heterogeneous than the sand (Fig. 1). A number was etched onto each mussel's MUSSEL HABITAT SELECTION 207 TABLE 1. Loglinear model analysis showing the significance of “SOURCE” (area where mussel was collected in Inner Long Point Bay), “INITIAL SUBSTRATE” (substrate in which the mussel was initially planted in the experimental ponds), and the interaction of the two effects in predicting the final substrate of the mussels. — __— e ++ + + Source df SOURCE 1 INITIAL SUBSTRATE 1 INTERACTION 1 shell and 50 individuals from each exposure area were placed at randomly generated co- ordinates on the bottom of each of the ponds on 12 June 1985. By 18 June, there was am- ple evidence of mussel movement within the ponds (i.e. tracks). Because of concern about the use of city water, various physico-chem- ical and biological parameters were moni- tored. Chlorine (Hach Model CN-70) and dis- solved oxygen (Hach Model А!-33) analyses were carried out throughout the experimental period and showed total chlorine concentra- tions of 0.2-0.3 mg : L”* (tap water in London was about 0.6-0.8 mg : L”*) and dissolved oxygen concentrations of 90-100% satura- tion. Temperature over the experimental pe- riod ranged from 16-29°C. Flow rate from the taps into the ponds was checked daily and kept at 125 mLsec '. Qualitative sampling with a plankton net on 2 July 1985 revealed abundant insect, crustacean zooplankton, Hydracarine, and algal populations in both of the ponds. Four months after planting the mussels in the ponds (9 October 1985), 151 individuals (142 alive) were recovered over a two-day period (using SCUBA) and the ponds were drained. Eight additional (dead) mussels were found the following day, and 23 dead mussels were recovered from the dry ponds the following spring. Because the live and dead mussels did not differ in their distribution patterns, data on all recovered individuals were used in the statistical analyses. Shells of the recovered mussels were cleaned, dried, weighed, and measured (length, height, and width as defined in Bailey & Green 1988), and the morphological differences between those collected in the sand and the mud were con- sistent with differences observed by Bailey & Green (1988). The habitat from which each mussel was originally collected in the field (“SOURCE”), the substrate in which the mussel was initially placed in one of the ponds (“INITIAL SUBSTRATE”), and the interaction of these two factors were tested as predictors of the x p 2.9 0.08 17.4 <0.001 0.13 0.72 mussel's final substrate “choice” using а log- linear model (Fienberg, 1980). SAS Proc Cat- mod (SAS Institute Inc., 1982) was used for the analysis. RESULTS Two-thirds of the mussels recovered (124/ 182) at the end of the experiment were found in the mud substrate. The loglinear model analysis (Table 1) showed that this prefer- ence for mud was somewhat influenced (p = 0.08) by the “SOURCE” of the mussels and more strongly affected by their “INITIAL SUBSTRATE.” There was no interaction be- tween these two effects. Compared to mus- sels collected in the muddy areas of Inner Long Point Bay, more of the mussels col- lected in exposed, sandier areas of the bay tended to either stay in mud if they started there, or move to mud from sand (Fig. 2). In both groups, there was a tendency for those initially placed in mud to stay there, but those initially placed in sand had about a 50/50 chance of switching to mud (Fig. 2). DISCUSSION Although both the sand- and mud-collected mussels appeared to select habitat, the two forms differed only in the magnitude (rather than the nature) of their habitat selection. A greater proportion of the sand-collected mus- sels starting in mud stayed in mud, and a greater proportion of sand-collected mussels moved to mud from sand, but both groups showed similar basic patterns of habitat choice (Fig. 2). There are at least two expla- nations for this: (i) the two phenotypes do not represent specialists for different habitats, and (ii) the two substrate types used in the experiment did not adequately recreate the habitat choices available to these mussels in their natural environment. 208 BAILEY a 100 = о (dp) o OÙ os (= 200 re} a = 40 $ = 20 © ge 0 MM MS Ш Sand-collected OlMud-collected 55 SM Group FIG. 2. Initial placement and final substrate of recovered mussels. The percentage of the total for a given SOURCE group (i.e. sand- or mud-collected) is given (MM: initial = mud, final = mud; MS: initial = mud, final = sand; SS: initial = sand, final = sand; SM: initial = sand, final = mud). It has previously been proposed that the smaller, more obese shells of freshwater mussels living in soft mud habitats simply re- flect a non-adaptive response to poorer grow- ing conditions. Food supply may be reduced in these areas (Ball, 1922; Stansbery, 1970; Kat, 1982), but this hypothesis has never been tested. Feeding behavior may also differ in soft sediment habitats. Ellis (1936) ob- served that mussels in muddy water had their valves closed 75-90% of the time, while those in silt-free water were closed less than 50% of the time. He also found that heavy silting killed most of the mussels kept in ex- perimental tanks. Kat (1982) argued that the net intake of energy would be reduced on muddy substrates because the mussels would require more energy to maintain proper filtering position. As in the case of the “adaptive hypotheses” (see Introduction), lit- tle direct evidence has been collected to re- ject either the “adaptive” or “environmental” hypotheses of variation in shell morphology. Thus, the difference in shell morphology between sand- and mud-collected mussels may indicate different growing conditions rather than differential adaptation to their re- spective habitats. If this were true, the two phenotypes would not represent specialists for the two habitat areas in Inner Long Point Bay, and no difference in habitat choice would be expected. Sand-collected mussels may have exhibited a greater degree of pickiness because of size-dependent controls on the proximal mechanism of habitat selection in these mussels. Perhaps differences in short- term fitness of mussels in the two sediments (e.g. filtering efficiency, maintenance of shell position), which would provide the necessary cues for stimulating habitat selection, were not as great for the mud-collected mussels. The substrate choices available in the pond experiment may not have adequately repre- sented habitat variation in the natural environ- ment. The most obvious evidence supporting this contention is the clear choice of the “mud” sediment in the ponds by mussels col- lected from the sandy area of Inner Long Point Bay. The particle size distribution of “typical” sediment samples from muddy and sandy areas in Inner Long Point Bay (Fig. 3) are clearly more similar to the “mud” than the “sand” sediment in the ponds (Fig. 1), al- though the “mud” sediment in the ponds was somewhat more heterogeneous than the nat- ural sediments. Also, there were many differ- ences between the sandy and muddy areas in the bay that were not recreated in the exper- iment, such as macrophyte and fingernail clam communities (Bailey, 1988), organic MUSSEL HABITAT SELECTION 209 100 EN mn © о о о Percent Finer № o 0.01 El т 0.1 | Grain Size (mm) FIG. 3. Particle size distribution of “typical” substrate collected from sandy (- - of inner Long Point Bay, Lake Erie. content (Bailey, 1988) and penetrability (Bai- ley, personal observation) of the sediment, and the actual turbulence that created and maintains the sediment variation in the bay. None of these correlated environmental dif- ferences were present in the pond experi- ment, and thus weakened its relevance to the natural environment. On the other hand, the grain size stimulus for habitat selection in L. r. siliquoidea must have been quite strong to have generated the observed results. Even though both groups of mussels ap- peared to select the mud sediment in the ponds, the nature of this and similarly de- signed substrate selection experiments (e.g. Meier-Brook, 1969; Gale, 1971; Huehner, 1987) allows for another interpretation. The relatively slow-moving bivalves must move through the two substrates available. If one of the substrates is considerably harder to move through than the other, the mussels will accumulate in that substrate and appear to have “chosen” it at the end of the experiment. This possibility, which may be likened to a food choice experiment in which one of the diet alternatives makes it physically impossi- ble for the animal to eat anything else, might be called the “stuck in the mud” hypothesis (R. H. Green & S. G. Hinch, personal com- munication). Although regular observations of - -) and muddy (——) areas the ponds revealed numerous tracks through both sediment types, detecting any difficulty in movement was beyond the scope of this study. If one does accept that habitat selection was demonstrated by L. r. siliquoidea, how relevant is this to the behavior of the mussel in its natural habitat? Many authors have found that juvenile mussels, after finishing a life stage during which they are parasitic on fish, occupy a habitat somewhat different from adults of the same species (e.g. Lefevre & Curtis, 1912; Isely, 1911; Coker et al., 1921). Perhaps at some time between the ju- venile dropping from the fish host and the rel- atively sedentary adult stage (Strayer, 1981; but cf. Salmon & Green, 1983), selection of an appropriate adult habitat should occur. Whether or not habitat selection would evolve would depend on how much would be gained by selecting habitat (i.e. benefits of habitat se- lection) relative to the time and energy spent searching for the habitat (i.e. costs of hab- itat selection). The hypothesis that the ability to select habitat has evolved in L. r. sili- quoidea seems credible. This experiment has shown (with the aforementioned reservations) that the ability to select habitat exists in these mussels. This evidence strengthens conclu- sions from observational, frequency of occur- 210 BAILEY rence data and short-term laboratory experi- ments (e.g. Huehner, 1987). There is no evidence, however, that the sand- and mud- collected mussels from Inner Long Point Bay specialize on different habitat types. Either the difference in shell phenotype between the groups is a non-adaptive, environmentally in- duced effect or the habitats available in the pond experiment were not suitable for detect- ing a difference in preference. ACKNOWLEDGEMENTS To those who toiled in the ponds (Cindy Walker, Scott Hinch, Helene Dupuis, Karen Watkinson), | give thanks. The Canada Cen- tre for Inland Waters (Burlington) loaned me a boat for field work in Inner Long Point Bay. The Ontario Ministry of Natural Resources loaned some docking space. Miles Keenley- side facilitated use of the ponds. В. H. Green, P. Handford, T. M. Laverty, and D. Strayer read the manuscript and improved it with their comments. This project was funded by NSERC Operating and Ontario Ministry of the Environment grants to R. H. Green, and an NSERC Postgraduate Scholarship to RCB. LITERATURE CITED BAILEY, R. C., 1988, Correlations between species richness and exposure: freshwater molluscs and macrophytes. Hydrobiologia, 162: 183-191. BAILEY, R. C. & R. H. GREEN 1988, Within-basin variation in the shell morphology and growth rate of a freshwater mussel. Canadian Journal of Zo- ology, 66: 1704-1708. BALL, G. H., 1922, Variation in freshwater mussels. Ecology, 3: 93-121. BOWLES, J. E., 1978, Engineering properties of soils and their measurement, 2nd edition. Mc- Graw-Hill. COKER, В. E., А. Е. SHIRA, H. W. CLARK 4 A. D. HOWARD, 1921, Natural history and propaga- tion of freshwater mussels. Bulletin of the U.S. Bureau of Fisheries, 37: 77-181. EAGAR, R. M. C., 1978, Shape and function of the shell: a comparison of some living and fossil bi- valve molluscs. Biological Reviews, 53: 169- 210. ELLIS, M. M., 1936, Erosion silt as a factor in aquatic environments. Ecology, 17: 29-42. FIENBERG, S. E., 1980, The analysis of cross- classified categorical data. MIT Press. Cam- bridge, Mass. GALE, W. F., 1971, An experiment to determine substrate preference of the fingernail clam, Sphaerium transversum (Say). Ecology, 52: 367-370. HINCH, $. G., В. С. BAILEY & В. Н. GREEN, 1986, Growth of Lampsilis radiata (Bivalvia, Unionidae) in sand and mud: a reciprocal transplant experi- ment. Canadian Journal of Fisheries and Aquatic Science, 43: 548-552. HUEHNER, M. K., 1987, Field and laboratory de- termination of substrate preferences of unionid mussels. Ohio Journal of Science, 87: 29-32. ISELY, Е. B., 1911, Preliminary note on the ecology of the early juvenile life of the Unionidae. Biolog- ical Bulletin, 20: 77-80. KAT, P. W., 1982, Effects of population density and substratum type on growth and migration of El- liptio complanata (Bivalvia, Unionidae). Malaco- logical Reviews, 15: 119-127. LEFEVRE, G. & W. C. CURTIS, 1912, Studies on the reproduction and artificial propagation of freshwater mussels. Bulletin of the U.S. Bureau of Fisheries, 30: 105-201. MEIER-BROOK, C., 1969, Substrate relations in some Pisidium species (Eulamellibranchiata: Sphaeriidae). Malacologia, 9: 121-125. SALMON, A. & R. H. GREEN, 1983, Environmental determinants of unionid clam distribution in the Middle Thames River, Ontario. Canadian Journal of Zoology, 61: 832-838. SAS INSTITUTE INC, 1982, SAS user’s guide: sta- tistics. SAS Institute Inc. Cary, N.C. STANLEY, S. M., 1970, Relation of shell form to life habits in the Bivalvia. Geological Society of America Memoirs, 125: 1-296. STANSBERY, D. H., 1970, A study of the growth rate and longevity of the naiad Amblema plicata (Say 1817) in Lake Erie. Bulletin of the American Malacological Union, 37: 78-79. STRAYER, D. L., 1981, Notes on the microhabitats of unionid mussels in some Michigan streams. American Midland Naturalist, 106: 411-415. WILSON, С. В. 8 Н. W. CLARK, 1914, The mussels of the Cumberland River and its tributaries. U.S. Bureau of Fisheries Report No. 781. Revised Ms. accepted 27 March 1989 MALACOLOGIA, 1989, 31(1): 211-216 SPERMATOCYTE CHROMOSOMES AND NUCLEOLUS ORGANIZER REGIONS (NORs) IN TRICOLIA SPECIOSA (MUHLFELD, 1824) (PROSOBRANCHIA, ARCHAEOGASTROPODA) R. Vitturi & E. Catalano Institute of Zoology, University of Palermo, Via Archirafi 18-90123 Palermo, Italy ABSTRACT The chromosome complement, n = 8 and 2n 16, of Tricolia speciosa is at present the lowest chromosome number found within the Archaeogastropoda (Mollusca: Prosobranchia). The karyotype consists entirely of bi-armed chromosomes. No heterotypic elements were ob- served in analyses of meiotic and mitotic chromosomes. An analysis of the nucleolar organizer region (NOR) by silver staining is reported. Tricolia speciosa presents an intraspecific variability in Ag-NOR pattern as revealed by differences in the number of Ag-NORs per cell within a cell population. Key words: Tricolia; karyology; nucleous organizer regions. INTRODUCTION Three thousand living species distributed in 22 families are currently recognized by Franc (1968) within the prosobranch order Archae- ogastropoda. Because karyological informa- tion is only available for 76 species from nine families (Vitturi et al., 1982; Nakamura, 1982, 1983, 1986), it is clear that many archaeogas- tropod species and families remain com- pletely unexplored. Previous studies on mitotic chromosomes morphology in 46 of the 76 examined species (Nakamura, 1986) revealed that 10-20 per- cent of the chromosome complements of ar- chaeogastropods consist of sub-telocentric (ST) and acrocentric (A) chromosomes, with higher values of metacentric (M) and sub-me- tacentric (SM) elements in the karyotypes of those species characterized by a low number of chromosomes, such as Patellidae and Ac- maeidae. Moreover, within this order, the haploid chromosome number varied from п = 9 (Patellidae) to n = 21 (Trochidae), with in- termediate values as briefly summarized in Table 1. Nakamura (1986) noted, however, that chromosome numbers were quite con- stant within each family, except for the Hali- otidae and Fissurellidae, in which there was some variation. The location of nucleolus organizer regions has been reported mainly for mammalian spe- cies (Goodpasture & Bloom, 1975; Pardue & Hsu, 1975: Markovic et al., 1978; Traut et al., 211 1984), and for a relatively few species of fish (Kligerman & Bloom, 1977; Foresti et al., 1981; Thode et al., 1983, 1985; Thode, 1987). With regard to Mollusca, results with silver staining have been described for the genera Bulinus and Biomphalaria (Mollusca, Planor- bidae) (Goldman et al., 1983). In the present paper, we describe sperma- tocyte chromosome of the species Tricolia speciosa, which belongs to the family Pha- sianellidae (Archaeogastropoda) previously unexplored at a karyological level. Addition- ally, we report here our findings concerning the distribution and behaviour of nucleolar or- ganizer regions (NORs) in this species. MATERIALS AND METHODS Thirty sexually mature male specimens of Tricolia speciosa collected in February 1987 in the Gulf of Palermo were employed. Taxo- nomic identification of the specimens was made according to the guidelines of Parenzan (1970), and voucher shells of ten specimens were deposited at the Museum of the Institute of Zoology of the University of Palermo. Meiotic chromosomes were obtained by treating testes according to the squashing technique described for other molluscan spe- cies (Vitturi et al., 1982). In order to obtain mitotic chromosomes, testes of ten speci- mens were treated before squashing with 212 VITTURI & CATALANO TABLE 1. Haploid chromosome numbers in Archaeogastropoda; (1) including one species reported to have various chromosome numbers number of species within = 9 10 11 12 13 Acmaeidae — 14 — Patellidae 5 == — — 4 Family Neritidae‘' Haliotidae Fissurellidae 1 Trochidae‘' = — — — — Turbinidae == — — — Stomatellidae == — = — — Helicinidae — Total 3 т 22 4 0.025% colchicine in double distilled water for 20 minutes. The same slides, after removal of the cover-glass, were then stained with silver ni- trate following the procedure of Howell & Black (1980). Acetic-orcein slides were photographed with a Wild phase contrast microscope, and NOR-banded slides with a Wild light micro- scope. Mitotic chromosomes were interpreted on the basis of the arm ratio, following the no- menclature proposed by Levan et al. (1964) OBSERVATIONS Acetic-orcein slides At the pachytene stage, all bivalents were tightly paired and their outlines were irregular (29-1): The analysis of 64 diakinetic plates gave the haploid number of 8 chromosomes (Fig. 2a). When disparate chromosome counts ос- curred (one plate with 6 chromosomes, three plates with 7, and four plates with 9 chromo- somes), the discrepancy was usually attrib- uted to either loss or breakage of bivalents. Almost all bivalents homogeneously stained appeared chiasmatic (Fig. 2b), and their lengths ranged from 2 um to 3 шт. At the spermatogonial metaphase stage (Fig. 3a), all 16 elements showed no achro- matic area, with the exception of a pale me- dial zone corresponding to the centromere re- gion, and thus appeared randomly distributed on the squashing plane. From an analysis of the idiogram (Fig. 3b, one plate is repre- sented) combined from the chromosomes of Total examined species = === 14 — — — — = 5 = = = 23 — — — 8 = — — 6 14 | a wal «| | y _ NE 1 я == 5 o | № Rw | | © five metaphase plates and arranged on the basis of their decreasing size and centromere position (Fig. 4, Table 2), it appears that all pairs were metacentric except for one (Figs. 3b, 4, arrows) that was sub-metacentric. NOR-banding slides Analysis of nuclei stained by the silver method revealed a variability in the number of nucleoli/nucleus, and the frequencies appear in Table 3. In Figure 5, the two areas showing an in- tense silver deposit were of larger dimensions than the six areas observed in Figure 7. In Figure 6, a nucleus with three nucleoli is visible. A summary of the state at diakinesis is as follows: 60% of analysed spreads show a completely NOR negative appearance (Fig. 8), 30% have 2-3 elements with NORs гер- resented by minute dots (Fig. 9, arrows), and 10% have almost all elements with Ag gran- _ules (Fig. 10, arrows). Mitotic chromosomes at the prophase stage often show NOR positive areas not as- sociated with the chromosomes (Fig. 11, arrow). In the same figure, the element indi- cated by two arrows has a large telomeric NOR-band. Variability in the number of NOR positive elements and the size of Ag-NORs was also observed. At the metaphase stage, spreads with ei- ther three Ag-NOR chromosomes (Fig. 12, ar- rows) or with five or six NOR-elements were present (Fig. 13, arrows). DISCUSSION From our observations, it seems that the course of spermatogenesis in Tricolia spe- CHROMOSOMES IN TRICOLIA 213 ecw < BG Ye: ; MN en a . a И M UT es MALE sr: © 4 = x vo Oo . LAN 5 4 и dd Q © ae Er „um , O nO et 13 FIG. 1. Pachytene chromosomes in male gonads of Tricolia speciosa. FIG. 2. (a) and (b) diakinetic bivalents of T. speciosa. FIG. 3. (a) spermatogonial metaphase chromosomes and (b) karyotype of T. speciosa (arrow indicates sub-metacentric pair). FIG. 4. Idiogram constructed from five metaphase plates of T. speciosa (arrow indicates sub-metacentric pair). FIG. 5. Ag-nucleus with two nucleoli. FIG. 6. Ag-nucleus with three nucleoli. FIG. 7. Ag-nucleus with six nucleoli. FIG. 8. NOR-negative diakinetic plate of T. speciosa. FIG. 9. NOR-positive diakinetic plate of T. speciosa (arrows indicate Ag-positive elements). FIG. 10. NOR-positive diakinetic plate of T. speciosa (arrows indicate Ag-positive elements). FIG. 11. Mitotic chromosomes at prophase stage of T. speciosa (arrows indicate Ag-NORs). FIG. 12. Mitotic metaphase chromosomes of T. speciosa (arrows indicate Ag-NORs). FIG. 13. Mitotic metaphase chromosomes of T. speciosa (arrows indicate AG-NORs). 214 VITTURI & CATALANO TABLE 2. Mean length and arm ratio of the chromosomes of five metaphase plates of Tricolia speciosa. Chromosome Mean length, Arm ratio Centromere pairs D SD mean position © | O O1 R G ND) — № |+ o > > [ep] RES SES FEES ES TABLE 3. Frequency of nucleoli/nucleus in Tricolia speciosa. No. of nucleoli/nucleus 1 2 3 4 5 6 Nuclei 32 40 107 517 28 5 Frequencies 12 15 41 LAA 2 % ciosa does not differ from that of other mol- luscan species (Patterson, 1969). Cytological characteristics such as pachytene chromo- somes with irregular outlines and chiasmatic bivalents, constantly reported within the Mol- lusca (Vitturi et al., 1982; Vitturi & Catalano, 1984; Vitturi et al., 1985b; Vitturi et al., 1986), were observed. Distant somatic pairing between homolo- gous chromosomes at the metaphase stage has been described for Haliotis tubercolata (Prosobranchia, Archaeogastropoda) (Co- lombera & Tagliaferri, 1983a) and Acantho- chiton crinitus (Polyplacophora) (Colombera & Tagliaferri, 1983b) but was not seen in our preparations. In fact, a random distribution of the mitotic metaphase chromosomes on the squashing plane was observed. The absence of heterotypic elements among spermatocyte bivalents, and of heter- omorphic pairs among male mitotic chromo- somes, allowed us to exclude a XY sex-de- termining mechanisms in Tricolia speciosa. At present, within the Archaeogastropoda only species included in the family Neritidae show a male ХО sex-chromosome system (Naka- mura, 1983; Vitturi & Catalano, 1988). How- ever, a chromosome value of 8 bivalents ob- served for Tricolia speciosa suggests that this species has the lowest chromosome number within the Archaeogastropoda (Table 1). If we accept the idea that evolution in gen- eral (Mayr, 1970; Colombera & Lazzaretto- Colombera, 1978), and within the phylum Mollusca in particular (Vitturi et al., 1982; Ra- sotto & Cardellini, 1983; Vitturi et al., 1985а), proceeds via a decrease of chromosome number, although exceptions are certainly known (Vitturi et al., 1983), then the special- ization of Tricolia speciosa is apparent. More- over, it is held that evolved karyotypes are more symmetrical than those observed in the generalized species (Ohno, 1970; Colombera & Vitturi, 1978; Vitturi et al, 1987). If so, the specialization of Tricolia speciosa, which is remarkable in having all bi-armed chromo- somes, would be further supported. Data obtained from this study suggest that the Ag-staining pattern was, in this species, variable, as shown by the differences in the number of nucleoli/nucleus and in the number of chromosomes involved in the nucleolar or- ganization. This variability, previously re- ported in fish (Howell & Black, 1979; Foresti et al., 1981; Thode et al., 1983) and in mam- mals (Goodpasture & Bloom, 1975; Hender- son et al., 1976; Dev et al., 1977; Mikelsaar et al., 1977a,b; Winking et al., 1980), is currently interpreted as a differential transcriptional ac- tivity of the ribosomal DNA (Miller et al., 1976). Our results showing a correlation be- tween the number of nucleoli and their dimen- sions seem to be consistent with the idea that nucleoli in interphase tend to fuse (Goldman et al., 1983). Because chromosomes stained with acetic- orcein showed no achromatic zones, NORs are in our opinion unrelated to any satellite region in the species under study. In Gobius fallax (Pisces, Gobiidae) (Thode et al., 1983) and in other fish species (Almeida Toledo et _al., 1981), the same conclusion was reached. Comparatively small Ag dots in the chromo- somes of diakinesis involving from zero to al- most all bivalents, were observed. This fact leads us to speculate that in this species, as in human cells (Schwarzacher et al., 1978), a decrease in the NORs activity at meiotic metaphase-| occurs. However, in Tricolia speciosa it seems that a higher number of elements are involved in this activity at mei- otic metaphase-I rather than at mitotic stages. ACKNOWLEDGMENTS This research was supported by grant: Ricerca Scientifica 60%, 1986-87. CHROMOSOMES IN TRICOLIA 215 LITERATURE CITED ALMEIDA TOLEDO, L.F., F. FORESTI & F.S.A. TOLEDO, 1981, Constitutive heterochromatin and nucleolus organizer region in the knife fish Apteronotus albifrons (Pisces, Apteronotidae). Experientia, 37: 953-954. COLOMBERA, D. & I. LAZZARETTO-COLOM- BERA, 1978, Chromosome evolution in some ma- rine invertebrates. InB. BATTAGLIA & J. BEARD- MORE, eds., “Marine organisms,” pp. 487-525. COLOMBERA, D. & F., TAGLIAFERRI, 1983a, Chromosomes from male gonads of Haliotis tu- bercolata and Haliotis lamellosa (Haliotidae, Ar- chaeogastropoda, Mollusca). 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ALVAREZ, 1983, As- sociation of nucleolus organizer chromosomes shown by silver staining in Gobius fallax. Journal of Heredity, 74: 480-482. TRAUT, W., H. WINKING & S. ADOLPH, 1984, An extra segment in chromosome 1 of wild Mus musculus a C-band positive homogeneously staining region. Cytogenetics and Cell Genetics, 38: 290-297. VITTURI, R., P. CARBONE & E. CATALANO, 1985a, The chromosomes of Pycnodonta co- chlear (Poli) (Mollusca, Pelecypoda). Biologis- ches Zentralblatt, 104: 177-182. VITTURI, В. & Е. CATALANO, 1984, Spermatocyte chromosomes in 7 species of the sub-class Prosobranchia (Mollusca, Gastropoda). Biologis- ches Zentralblatt, 103: 69-76. VITTURI, В. & Е. CATALANO, 1988, A male ХО sex-determining mechanism in Theodoxus me- ridionalis (Neritidae) (Prosobranchia, Archaeo- gastropoda). Cytologia, 53: 131-138. VITTURI, R., Е. CATALANO & М. MACALUSO, 1986, Chromosome studies in three species of the Gastropod superfamily Littorinoidea. Malaco- logical Review, 19: 53-60. VITTURI, R., E. CATALANO, M. MACALUSO & A. MAIORCA, 1987, Spermatocyte chromosomes in six species of Neogastropoda (Mollusca, Prosobranchia). Biologisches Zentralblatt, 106: 81-88. VITTURI, R., E. CATALANO, М. MACALUSO & М. PARRINELLO, 1985b, The chromosomes of cer- tain species of the sub-class Opisthobranchia (Mollusca, Gastropoda). Biologisches Zentral- blatt, 104: 701-710. VITTURI, R., A. MAIORCA & E. CATALANO, 1983, The karyology of Teredo utriculus (Gmelin) (Mol- lusca, Pelecypoda). Biological Bulletin, 165: 450-457. VITTURI, R., M.B. RASOTTO & N. FARINELLA- FERRUZZA, 1982, The chromosomes of 16 mol- luscan species. Bollettino di Zoologia, 49: 61-71. WINKING, H., K. NIELSEN & A. GROPP, 1980, Variable positions of NORs in Mus musculus. Cy- togenetics and Cell Genetics, 26: 158-164. Revised Ms. accepted 4 October 1988 MALACOLOGIA, 1989, 31(1): 217-227 FEEDING EXPERIMENTS ON AND ENERGY FLUX IN A NATURAL POPULATION OF THE EDIBLE SNAIL HELIX LUCORUM L. (GASTROPODA: PULMONATA: STYLOMMATOPHORA) IN GREECE A. Staikou & M. Lazaridou-Dimitriadou Laboratory of Zoology Department of Biology, University of Thessaloniki, 54006 Thessaloniki, Greece ABSTRACT Energy flux in Helix lucorum was studied using as food Lactuca sativa, Urtica dioica and Petasites albus. The highest daily consumption and assimilation rates were observed in newly hatched snails and the lowest rates in adult snails. Assimilation efficiency, mean monthly pro- duction, as well as the growth (Pg/l%) and ecological (Pg/A%) efficiencies, fluctuated with season, the generation and with the physiological state of the snails. Snails fed on L. sativa showed higher assimilation efficiency than those fed on U. dioica or P. albus. Ingestion rate was found equal to 19.7% if snails were fed on U. dioica and 14.6% if they were fed on P. albus. Energy flow through H. lucorum population was 51.7 Kcal/m?/year if snails were fed on U. dioica and 29.2 Kcal/m?/year if they were fed on P. albus. Key words: feeding experiments; energy flux; consumption; nutritional budget; Helix lucorum. INTRODUCTION Ingestion and assimilation are two essential phases of energy transport from one trophic level to another, and thus they compose an important part of ecosystem functioning. Ter- restrial gastropods, as primary consumers, play an important role in matter and energy transport from producer level to upper trophic levels. Studying the role of terrestrial molluscs in dynamics of woodland ecosystems, first Lindquist (1941) and then Mason (1970b) stressed the need for quantitative studies on food consumption and assimilation. Many studies have been published since on terres- trial pulmonates, such as those of Stern (1968, 1975) on Arion rufus and Agriolimax reticulatus, of Jennings & Barkham (1976) on Arion ater, of Zeifert & Shutov (1978, 1981) on Bradybaena fruticum and Eobania vermic- ulata, of Lazaridou-Dimitriadou & Daguzan (1978) on Euparypha pisana, of Charrier & Daguzan (1980) on Helix aspersa, and of Lazaridou-Dimitriadou & Kattoulas (sub- mitted) on Eobania vermiculata. Similarly, many studies on population bioenergetics of freshwater pulmonates and prosobranchs ex- ist, such as those of Aldridge et al. (1986) on Viviparus georgianus, of Russell-Hunter et al. 217 (1983, 1984) on Helisoma trivolvis and Lym- naea palustris, and of Aldridge (1982) on Lep- toxis carinata, etc. The present study forms part of a wider in- vestigation into ecophysiology of the edible snail Helix lucorum in Greece. Reported here are the results concerning the experiments on food consumption and assimilation in the lab- oratory, and estimates of population metabo- lism in the field. METHODS AND MATERIALS The experiment lasted from April 1984 to March 1985. The snails used in the experi- ment were collected from a natural habitat of Helix lucorum in the Logos region of Edessa, northern Greece, where its ecology and biol- ogy have been studied. Every month, nine snails from each generation present in the field at that time were collected and trans- ferred to the laboratory. The number of gener- ations was known from the demographic analysis of the populations of Helix lucorum. Adult snails have a wide overlap of genera- tions that could not be distinguished; there- fore, the assumption that adults of different ages (snails with an age of three years or more) belong to the same cohort was taken 218 STAIKOU & LAZARIDOU-DIMITRIADOU into account (Staikou et al., 1988). During winter months, that is December, January and February, no experiments were done be- cause the snails hibernated. The experiments were carried out in the laboratory under semi-natural conditions. Lighting followed the natural cycles, and tem- perature coincided with natural temperature at the given month. Snails were kept in indi- vidual glass chambers (40 x 20 x 15 cm), and high humidity (— 85%) was supplied by a piece of sponge soaked with water and a small pot of water. Three different kinds of food were used: (a) Lactuca sativa, which in general is considered as “good” food for snails, and (b) Urtica dioica and Petasite sal- bus, which were the most abundant food re- sources in the study site of Helix lucorum. There were three replicates for each kind of food, that is nine replicates for each genera- tion. Each month, 36 to 54 chambers were used depending on the number of genera- tions that existed in the field. The methodology followed was that of Laz- aridou-Dimitriadou & Daguzan (1978). The amount of excrement produced daily was de- termined by means of a marker technique (Phillipson, 1960). Before the experiment, snails were fed carrot slices, which resulted in colour-marked faeces. Then the snails were weighed, measured and exposed to the ex- perimental food, which was presented in pieces of specific surface area (4 cm x 4 cm). Food was replaced every 24 hours. The amount of food consumed was estimated as the area grazed by the individual snails, mea- sured by the surface area of the remnant with a planimeter. This method was used as it gave the best results after preliminary exper- imentation with other methods, such as the difference of live weight between the food given to the snails and control food material kept under the same conditions (Bogucki & Helczyk-Kazecka, 1977). The method of dry- ing food material, weighing, then rehydrating, giving it to the snails, and then drying and weighing again, which has been shown useful in feeding experiments with aufwuchs as food for fresh- water snails (Tashiro et al., 1980), could not be used, as our snails would not feed on food treated this way. The dry weight of food consumed was calculated for each kind of food by using the regression equations of leaf surface on leaf dry weight (16 cm? of L. sativa is equal to 0.043 + 0.0064 g dry weight, 16 cm? of U. dioica is equal to 0.0518 + 0.0095 g dry weight, and 16 cm? of P. albus is equal to 0.0379 + 0.0037 g dry weight). The above equations were obtained by using 60 pieces of 16 cm? from each kind of food; 30 pieces were collected during spring (April) and 30 more during autumn (October); their dry weight was obtained after drying in vacuo in the presence of CaCOz. The faeces of each snail were collected, dried and weighed. After the experimental period, which lasted seven days, the snails were again measured, weighed and given carrot food. The faeces were collected until the coloured marker faeces appeared. At the end of each experi- ment, the snails were killed, the shell was separated from the body and both were dried in vacuo at room temperature in the presence of CaCO;. Dry weights of shell and body were taken seven days later. To quantify the daily consumption and as- similation rates as well as the growth and eco- logical efficiencies, the same formulae as Lazaridou-Dimitriadou & Kattoulas (sub- mitted) and the |.B.P. global productivity sym- bols listed by Petrusewicz & Macfayden (1970) were used. (mg) Daily consumption rate = L.W.(g) | FU(mg) Daily faecal production rate = L.W.(g) Е Pe te C(mg)-FU(mg)* Daily assimilation rate = —— L.W.(g) C(mg)—FU(m Assimilation efficiency = ИО) EMS) C(mg) _ Production (Pg) ог GP = the amount of dry tis- sue elaborated in the snail body and shell per unit of time (mg/month) Pg(m Growth efficiency = sing) x 100 (or gross growth efficiency) | (mg) P Ecological efficiency = (or net growth efficiency) *С (mg)—FU (mg) stands for TA (total assimilated) accord- ing to conventional component labels (Russell-Hunter & Buckley, 1983) ENERGY FLUX IN HELIX LUCORUM 219 [where C** = dry weight of food consumed daily, FU*** = dry weight of faeces produced daily, L.W. = mean snail live weight (body + shell), | = dry weight of food ingested per month (C(mg) x 30), A = dry weight of food assimilated per month (C(mg) x 30— F(mg) x 30)]. Monthly production, that is dry-weight gain of each snail could not be directly measured. К was extrapolated by the regressions of the dry body and shell weight in relation to the largest shell diameter(D) and the calculated organic content of the shell. Different regres- sions were used for juvenile and adult H. /и- corum, because it was known from the study of the relative growth that their growth rate differs (Staikou et al., 1988): For D < 22 mm the following regressions, where Wb = dry body weight and Ws = dry shell weight, were used: Log Wb = 2.592 Log D -3.884 (N = 123, r? = 0.884) Log Ws = 3.16 Log D -4.7 (N = 123, r? = 0.835) | for 21 тт = D = 36 mm there were used: Log Wb = 2.801 Log D -4.11 (N = 163, r? = 0.754) Log Ws = 3.865 Log D -5.527 (N = 163, r? = 0.802) and for D > 36 mm there were used the fol- lowing: Log Wb = 3.338 Log D -4.945 (N = 118, r? = 0.319) Log Ws = 3.114 Log D -4.408 (N = 118, r? = 0.398) For the determination of the shell organic matter, a known quantity of homogenated shell material was treated with 5 N HCI solu- tion, the remainder was treated with distilled water six to seven times to wash away the calcium chloride (CaClz) left and then dried at 65°C. The shell organic matter was deter- mined as the residual weight of dry shell weight left after the above-described treat- ments. The replicability of these measures was checked by burning a known quantity of **C(mg) stands for TI (total ingested) according to conven- tional component labels (Russell-Hunter & Buckley, 1983) ***EU stands for NA (not assimilated) according to conven- tional component labels (Russell-Hunter & Buckley, 1983) homogenated shell material, after drying it to constant weight, in a muffle-furnace at 560°C to obtain by difference an ash-free dry weight. The best method of computing organic growth is microbomb calorimetry, that is as- sessment of energetic equivalents of organic biomass, or analyses of fat, protein and car- bohydrates at all stages (Russell-Hunter et al., 1968). Another widely used method is es- timating organic carbon by wet oxidation (Russell-Hunter et al., 1968), and the C/N ra- tio at all stages. In this study, bomb calorim- etry was used mainly to produce comparable results with most of the existing studies on terrestrial snails. Thus, all rates of consump- tion, egestion and assimilation, as well as production and growth and ecological effi- ciencies, were computed in terms of both dry weight and energetic values. The energy con- tent of H. /исогит body, shell organic matter, and faeces, as well as the energy content of the three food materials, was determined ona Phillipson microbomb calorimeter. For each sample, two subsamples were burnt and whenever a difference greater than 0.05 ap- peared a third and sometimes a fourth sub- sample was used. Appendices with detailed calculations of all the rates and efficiencies used can be ob- tained by the Department of Zoology, School of Biology, Aristotelion University of Thessal- oniki, 54006 Thessaloniki, Greece. RESULTS The percentage of organic matter in the shell of H. /исогит was found to equal 1.7%. The caloric value of the organic material of the shell was 4.797 + 0.24 cal/mg ash free dry weight. A comparison between dry weight of food eaten and dry weight of faeces produced re- vealed a positive correlation between the above two parameters for all food materials used. Coefficient correlation was very high for animals fed on Lactuca (r = 0.951, N = 43) and Petasites (r = 0.907, N = 43) and some- what lower for animals fed on Urtica (r = 0.751, N = 43). The highest values for daily consumption rate were observed in newly hatched snails, aged one month for animals fed on Lactuca (89.55 mg/g) and Urtica (61.73 mg/g), and in juveniles aged three months for animals fed on Petasites (28.26 mg/g). Values of this pa- rameter declined with age and became very 220 STAIKOU & LAZARIDOU-DIMITRIADOU low in mature animals with a largest shell di- ameter greater than 35 mm. For animals fed on Lactuca, the lowest value observed was 2.63 mg/g. For those fed on Urtica, 1.11 mg/g, and for those fed on Petasites, 0.07 mg/g. Values of daily faecal production rate and daily assimilation rate followed the general pattern of daily consumption rate for all kinds of food used. The values of the above parameters of the individual nutritional budget of the snails were also influenced by the time of the year or by the physiological state of the animals. Thus, high values appeared during spring, espe- cially in May, and autumn (September, October). Also, high values in adult snails were shown in June before the reproductive period. Overall assimilation efficiency was higher and more constant in animals fed on Lactuca (82%) than in animals fed on Urtica (73%) and Petasites (59%) (Table 1). Values of this parameter calculated for the different gener- ations showed that young snails prefer Lac- tuca and Urtica and show a smaller prefer- ence for Petasites. Mature snails show a marked preference for Lactuca while their as- similation efficiency was almost the same, ranging from 30%—80% when fed on Иса or Petasites (Figs. 1-3). Values of mean monthly production (Pg), growth (Pg/l) and ecological (Pg/A) efficien- cies varied with the season and/or the phys- iological state of the snails, becoming highest in June irrespective of the kind of food. Also, high values were observed in September or November and sometimes in March and April (Figs. 1-3). In general, values of growth and ecological efficiencies were higher in snails fed on Pet- asites and lower in snails fed on Urtica or Lac- tuca (Table |). It has to be stressed, though, that these values were underestimated be- cause mucus production was not taken into consideration (Lamotte & Stern, 1987). Using the values of the calorific content of the body and the excrement of the snails at the end of each experiment, it was possible to convert the parameters of the individual nutri- tional budget of H. lucorum in caloric values (Table II). Values of monthly ingestion (El) and monthly assimilation (EA) fluctuated accord- ing to the season or/and the physiological state of the animals. Highest values were al- ways observed in late spring (May) and in au- tumn (September, October) (Figs. 1-3). Snails fed on L. sativa also showed high val- ues in June and July (Fig. 1). Fluctuations in production (EPg), gross growth (EPg/El) and net growth (EPg/EA) ef- ficiencies follow the same pattern as when these parameters are calculated in terms of dry weight (Figs. 1-3). Ingestion rate, which shows the popula- tions’ impact on the environment, was esti- mated from the values of annual turnover ra- tio (P/B = 1.24) (Staikou et al., 1988) as well as the values of growth efficiency EPg/El (which were 0.65 and 0.85 when snails were fed on Urtica or Petasites respectively). In- gestion rate was found equal to 19.7% if snails were fed on Urtica and 14.6% if they were fed on Petasites. Energy spent for egg production was cal- culated by: (a) the caloric content of eggs (Table Il), (b) the mean number of eggs laid (50.5 + 21.3), and (c) their mean weight (0.43 + 0.12 g.). By multiplying the eggs laid per snail per year by their mean weight, and then this number by the caloric content of eggs, the mean reproductive output in terms of energy values for any adult snail was assessed. Knowing the duration of life of H. lucorum (14 years) and the number of eggs laid by an in- dividual the first and following years (Staikou et al., 1988), the reproductive output in ener- getic values was calculated for the life span of H. lucorum. It was known by the feeding experiments the energy ingested and assimilated by an individual till its maturity, as well as the energy assimilated during a year of an adult's life. Multiplying the last value, which corresponds to an adult’s life, by the number of years an adult snail may live after the attainment of its _ maturity, it was possible to compute the indi- vidual energy budget of H. lucorum during its life time (Table I). It was found that of the total assimilated energy a snail spends 14.8% for growth, 2.3% for egg production, and 82.9% in metabolic energy when fed on Urtica, and 22.5%, 3.7% and 73.8%, respectively, when fed on Petasites. It was also found that the reproductive output was equal to 13.6% and 14.3% of the non-metabolic assimilated en- ergy when snails were fed on Urtica and Pet- asites respectively. DISCUSSION As stated by Russell-Hunter et al. (1968), the organic material in the shell represents 221 ENERGY FLUX IN HELIX LUCORUM TFT mm . . . . . . = — %G' CC %8 V1 %L'S %0'St %8'8 %7`5 % V3/d3 = = = aa = = %6 Il %C 6 %ch %9`8 %S'9 %8 € % 13/43 = = — = = = ZS c9 vl 6S El c8 % 13/V3 ABisus VALS c LS 9013 05'8 877 189 009891 181882 6991901 6/81 OLSPLL vSSG6c 9OLISN uUONONPOJd 66a 10, — — — = — — 6808 6808 6808 2802 1802 4802 juads ABiouz 1894 3811] ay] иоцопро.а 66e 10, — — — — — — 7191 7191 7191 cer zer zer juads ABiouz uononpoid 96 c Ol sol 091 сс Lig S0€8p 99715 09979 0397 9roll O6SOL YJMOIS) 9 zp 0'69 0'933 OC'OL + Sc cl9 vésric 98/178 cOccElLL v8PLS РУСЬ 150805 voNellWISSY 971 ZOLL /'GO€ er Zt 9'be 8'bZ 60pyS/€ 10899 940991 15818 ЕР 716915 uolsebu| 59/5894 Bonn 291227 5аи5веч вип en]9e7 e1eg (129) syyuou 891 ul (Bw) зциош gg} ul SONSPIOS POI) eonoe7 sejsejeg вип eonjoe7 (29) Aep auo ul (Bw) Aep auo uy 'SIBaÁ p| SI jeu} ‘эшц ay sy Buunp wn4oon] хуэн yO JeBpng Аблэиэ pue ¡euonunu lENPIAIPUI ayy jo 5лэ}эшелеа jediound ay] “| за 222 STAIKOU & LAZARIDOU-DIMITRIADOU 25000 Lactuca EI 20000 Ageia rn (cal) a {8 ni © (cal) 10000 АО 9124 6 68 10, Sig Si, 297117486 8.101233 84 185 | 86 | 87 188 al On ЕА/Е! sof Now, oe roa =. % 70 Lames ‘o-0-0+0, / Se 60 90 EPg/EA 40 30 20 a EPg/El À AN N; % o de? a RER sat À, а N xx rh VEN CLIM TUE 84 185 | 86 | 87 | 88 4000 3500 о? o EPg 3000 (cal) 2229? 2000 1500 У 1000 \ / o .o 500 $ 2 ; A 2 0 оо OHO+HHO-0-0H010-0HOHO0-0-0 94 ES Юзаю 84 185 186 | 87 | 88 Months FIG. 1. Mean monthly ingestion (cal) (El), mean monthly assimilation (cal) (EA), mean assimilation effi- ciences (%) (EA/El), ecological efficiencies (%) (EPg/EA), growth efficiencies (%) (EPg/El), and mean monthly production EPg (cal) during the life cycle of Helix lucorum fed on Lactuca sativa. [For the construction of Figure 1, the feeding experimental results of each generation (G1,G2,G3 or G4) known to be present in the field each month from April 1984 to March 1985 (according to the already published life-cycle data of Staikou et al., 1988) were combined in computations assuming that the first generation (G1) is followed by G2 at the end of the first year and С2 is followed by G3 at the end of the second year and G3 by G4 at the end of the third year. So feeding and growth parameters could be followed monthly from hatching till the maturity of the snails (except during winter time when the snails hibernate) that is for 3.5 years from September 1984 to March 1988, although feeding experiments lasted one year.] ENERGY FLUX IN HELIX LUCORUM 223 Utrica © 9 1 4268510837059 AR AS 84 185 Г 86 187, | 88 100 a N 90 т © во 9° \ = о © 0-0 ` о: e EA/EI 70 \/ o EN N о’ O54 4 x e о e ий 50 A o O NES A ANA 40 x | o EPg/EA 30 o N A % A N / A x PA x A x EPQ/El 10: à UWE: \ Mi. sur A $ 0 +Ж же Y AAA Y ++. O MM Х--Х-Ж-Ж Á Oia Ae CS LOSE IA OS LOS 84 185 | 86 | 87 | 88 3000 2500 о © 2000 | о EPg о о 1500 (са1) 1000 o o о o 500 / о’ / \ r © то ¿ o 0 EA 0 anes А GC RS DNS NS 7196 8103 84 185 | 86 | 87 | 88 Months FIG. 2. Mean monthly ingestion (cal) (El), mean monthly assimilation (cal) (EA), mean assimilation efficien- cies (%) (EA/El), ecological efficiencies (%) (EPg/EA), growth efficiencies (%) (EPg/El) and mean monthly production EPg (cal) during the life cycle of Helix lucorum fed on Urtica dioica [For the construction of Figure 2, the feeding experimental results of each generation (G1 ,G2,G3 or G4) known to be present in the field each month from April 1984 to March 1985 (according to the already published life-cycle data of Staikou et al., 1988) were combined in computations assuming that the first generation (G1) is followed by G2 at the end of the first year and G2 is followed by G3 at the end of the second year and G3 by G4 at the end of the third year. So feeding and growth parameters could be followed monthly from hatching till the maturity of the snails (except during winter time when the snails hibernate) that is for 3.5 years from September 1984 to March 1988, although feeding experiments lasted one year.] 224 El (cal) EA (cal) EA/EI EPg/EA % EPg/EI % EPg (cal) STAIKOU & LAZARIDOU-DIMITRIADOU Petasites 9000 IN 8000 7000 N © A 6000 A A 4 5000 \ à Г. A A ‘ 4000 A lo и 2 / 3000 ad о NA co Lo-o 2000 a bo. Y N | A =“ Whey} ! \ © 1000 t / x Wwe Yo. AOS o Lo Ott 0 +++ о: +2 ОТ 4 96. 18 110359 762 78.210773 84 185 | 86 187 188 =] А 90K o A y 80 ES A o 1a 78 a А / 0-0 90 A o 60 © ol o o R \ © N A 50 À nl | x \ o | o № 40 oo | \\ A | \/ x No 30 x \ A o|° 207 \ \ / NS тот £ о № Y \ (6) Vos 2 VOTA IVA 973117847767 тон 84 185 186 | 87 | 88 2500 © o 2000 O 1500 1000 o 500 Le 2 А © о Ро я о 0:0+0-0-0+ АА 9 114 ян 8 10 84 185 | 86 187 | és Months FIG. 3. Mean monthly ingestion (cal) (El), mean monthly assimilation (cal) (EA), mean assimilation efficien- cies (%) (EA/El), ecological efficiencies (%) (EPg/EA), growth efficiencies (%) (EPg/El) and mean monthly production EPg (cal) during the life cycle of Helix lucorum fed on Petasites albus. [For the construction of Figure 3, the feeding experimental results of each generation (G1,G2,G3 or G4) known to be present in the field each month from April 1984 to March 1985 (according to the already published life-cycle data of Staikou et al; 1988) were combined in computations assuming that the first generation (G1) is followed by G2 at the end of the first year and G2 is followed by G3 at the end of the second year and G3 by G4 at the end of the third year. So feeding and growth parameters could be followed monthly from hatching till the maturity of the snails (except during winter time when the snails hibernate) that is for 3.5 years from September 1984 to March 1988, although feeding experiments lasted one year.] ENERGY FLUX IN HELIX LUCORUM 225 TABLE 2. Calorific content, of Lactuca sativa, Urtica dioica and Petasites albus leaves, as well as of shell and egg matter of Helix lucorum (where N = number of trials, $ = standard deviation) K_—Á<— __—_— ei eee Mean Mean Mean ash Mean water cal/mg + $ cal/mg = $ weight weight Data with ash without ash SEIS yas Lactuca sativa 3.7689 + 0.2116 4.0040 + 0.2813 159 10/51 92.00 + 0.006 (N = 60) Urtica dioica 2.4093 + 0.2584 3.2705 + 0.2383 26.50 + 1.11 72.20 = 0.009 (N = 60) Petasites albus 3.9119 + 0.0933 4.2741 + 0.0882 8.14 + 0.19 89.00 + 0.008 (N = 60) Mean shell organic matter (N = 9) 4.2143 + 0.2830 4.7973 + 0.2452 18.40 + 0.12 75.20 + 5.30 Mean egg matter (N = 4) 3.1325 + 0.0482 3.8750 + 0.0799 20.52 + 0.42 82.40 + 3.20 stored energy that is never turned over until death, except where external erosion or inter- nal shell resorption takes place. The percent- age of the organic matter in the shell of H. lucorum was found lower than that reported for H. aspersa by Charrier & Daguzan (1980) and for Eobania vermiculata by Lazaridou- Dimitriadou & Kattoulas (submitted). It was somewhat similar to that reported by Lazari- dou-Dimitriadou & Daguzan (1978) for Eu- parypha pisana. The calorific content of the shell was similar to that reported by Hughes (1970) for the bivalve Scrobicularia plana, by Lazaridou-Dimitriadou & Daguzan (1978) for E. pisana, and by Charrier & Daguzan (1980) for H. aspersa. It was slightly lower than that reported by Lazaridou-Dimitriadou & Kattou- las (submitted) for E. vermiculata. High values of daily consumption rate, daily faecal production rate and daily assimilation rate in newly hatched snails may be due to their higher metabolic rate in relation to older ones. The same phenomenon has been ob- served in Arion ater (Jennings & Barkham, 1976), in Agriolimax laevis (Stern, 1979), in Eobania vermiculata (Zeifert & Shutov, 1978; Lazaridou-Dimitriadou & Kattoulas, submit- ted), in Euparypha pisana (Lazaridou-Dimitri- adou & Daguzan, 1978), and in many non- marine prosobranch gastropods (Aldridge et al., 1986). The season of the year seemed to influence the values of the above parameters. The peaks observed in spring (mainly in May) were probably related to the fact that this is the period of maximum activity for H. lucorum in the field (Staikou et al., 1988). Minor peaks observed in autumn (e.g. September or/and October) were probably due to the fact that snails are less active than in May but accu- mulate food reserves prior to hibernation. Seasonal fluctuations in values of these pa- rameters have been also reported by Lazari- dou-Dimitriadou 8 Kattoulas (submitted) for E. vermiculata. Seasonal degrowth has been shown in freshwater pulmonate gastropods (Russell-Hunter, 1983, 1984). High assimilation efficiencies in animals fed on Lactuca have been reported by Bogucki & Helczyk-Kazecka (1977) for adult H. pomatia and by Charrier 8 Daguzan (1980) for H. as- persa. Mason (1970a) and Richardson (1975a) also found that snails show higher assimilation rates when fed on Lactuca and much lower when fed on Urtica. Assimilation efficiency drops in October or November just before hibernation and in May or June when snails are fed on Urtica and in July-August when fed on Petacites when higher tempera- tures occurred in 1984 (Staikou et al., 1988, fig. 2). The less constant assimilation effi- ciency when snails are fed on Urtica and Pet- asites might be attributed to their different quality each month, because they were col- lected from the field, whereas Lactuca came from cultivations throughout the year. The ef- fects of food quality on assimilation and dif- ferential catabolism have been shown in non- marine gastropods (Aldridge et al., 1986). Assimilation efficiency in animals fed on Ur- tica is somewhat similar to that reported by Jennings & Barkham (1976) for Arion ater (69%) and by Lazaridou-Dimitriadou 4 Kat- toulas (submitted) for E. vermiculata (81%). It is higher than that reported by Mason (1970a) for Hygromia striolata (52.40-8.78%) and Discus rotundatus (47.70-8.89%) feeding on Urtica. The low efficiencies in the latter case may be due to the fact that Mason ran his experiments at 10°C. The peaks observed in the values of mean 226 STAIKOU & LAZARIDOU-DIMITRIADOU monthly production (Pg), growth (Pg/l) and ecological (Pg/A) efficiencies correspond to the months after the most rapid growth (March, April and mainly in June), or prior to hibernation (September to November) when food reserves are accumulated. The above differences were also assessed as changes in overall efficiencies or in physiological rates in non-marine prosobranch gastropods (Al- dridge et al., 1986). Ingestion rate when snails are fed only on Urtica accords with the value mentioned by Lazaridou-Dimitriadou & Kattoulas (sub- mitted) for E. vermiculata and by Richardson (1975b) and Williamson (1975) for Cepaea nemoralis. The calorific content of the snail’s body is comparatively low in relation to that of other animals (Slobodkin & Richman, 1961; Slo- bodkin, 1962; Golley, 1961), and this is prob- ably due to the low quantity of lipids in the snail's body (Hughes, 1970). Knowing the dif- ference in the calorific content of the bodies of the mature snails before and after the repro- ductive period (June: 12896.2 cal-August: 11647.3 cal = 1248.9 cal.) and the total re- productive output (1674 cal) (Table I), it was possible to calculate that 25.4% of the energy spent for egg production comes from concur- rent trophic input. Estimates of reproductive output as propor- tion of total assimilated energy (when snails were fed on Urtica or Petasites) accord well with the values given by Calow (1978) for some iteroparous fresh-water gastropods, whereas they were much lower than the val- ues given for the semelparous species. Esti- mates of reproductive output as a proportion of non-metabolic assimilated energy were lower than all the values reported by the same author for the iteroparous species, such as H. lucorum, and this may be related to the longer life span of H. /исогит. Knowing the mean number of snails in ev- ery size class/m? (Staikou et al., 1988), as well as the quantity of food consumed by them per month, it was possible to estimate the annual consumption and the annual fae- cal production of the snails in the field. If snails would feed only on Urtica, annual con- sumption would equal 15.81 g/m?, and annual faecal production, 3.54 g/m? (equivalent val- ues in calories were 51.7 Kcal/m?/year and 17.3 Kcal/m?/year); mean assimilation effi- ciency for all size classes was 77.6%. If snails would feed only on Petasites, the annual con- sumption would equal 6.8 g/m?, and annual faecal production, 2.6 g/m? (equivalent values in calories were 29.2 Kcal/m?/year and 13.1 Kcal/m?/year); mean assimilation efficiency for all size classes was 61.8%. The annual consumption values found in this study, are higher than those found by Mason (1970b) for different snail species fed on beech litter, by Jennings & Barkham (1976) for Arion ater, and by Zeifert & Shutov (1978) for Brady- baena fruticum. These differences may be due to the different density of the snail spe- cies in the field or to the different food used for the above studies. The difference in field den- sity may also be another reason for the higher values of annual consumption and energy flow through the population of E. vermiculata fed only on Urtica (Lazaridou-Dimitriadou & Kattoulas, submitted). ACKNOWLEDGMENTS Thanks are extended to K. Asmi for her technical assistance. Financial support was provided by the Minister of Agriculture. LITERATURE CITED ALDRIDGE, D., W. D. RUSSELL-HUNTER & D. BUCKLEY, 1986, Age-related differential catab- olism in the snail, Viviparus georgianus, and its significance in the bioenergetics of sexual dimor- phism. Canadian Journal of Zoology, 64: 340-— 346. ALDRIDGE, D., 1982, Reproductive tactics in rela- tion to life-cycle bioenergetics in three natural populations of the freshwater snail Leptoxis car- inata. Ecology, 63(1): 196-208. BOGUCKI, A. & B. HELCZYK-KAZECKA, 1977, Ef- ficiency of food assimilation in the Roman snail Helix pomatia L. Bulletin de la Société des Amis des Sciences et des Lettres de Poznan, Série D, 17 Livraison: 159-167. CALOW, P., 1978, The cost of reproduction—A physiological approach. Biological Review, 54: 23-40. CHARRIER, M. & J. DAGUZAN, 1980, Consomma- tion alimentaire: production et bilan énergétique chez Helix aspersa Müller (Gastéropode pul- топе terrestre). Annales de la Nutrition et de Г Alimentation, 34 (1): 147-166. GOLLEY, F. B., 1961, Energy values of ecological materials, Ecology, 42: 581-584. HUGHES, R. N., 1970, An energy budget for a tidal-flat population of the bivalve Scrobicularia plana (Da Costa). Journal of Animal Ecology, 39 (2): 357-381. JENNINGS, Т. J. & J. P. BARKHAM, 1976, Quan- ENERGY FLUX IN HELIX LUCORUM 227 titative study of feeding in woodland by the slug Arion ater. Oikos, Copenhangen, 27: 168-173. LAMOTTE, M. & G. STERN, 1987, Les bilans en- ergétiques chez les mollusques pulmonés. Hali- otis, 16: 103-128. LAZARIDOU-DIMITRIADOU, M. & J. DAGUZAN, 1978, Consommation alimentaire, production et bilan énergétique chez Euparypha pisana (Müller) (Gasteropode Pulmoné). Annales de la Nutrition et de |’ Alimentation, 32: 1317-1350. LAZARIDOU-DIMITRIADOU, M. & M. KATTOU- LAS (submitted). Energy flux in a natural popu- lation of the land snail Eobania vermiculata (Müller) (Gastropoda Pulmonata Stylommato- phora) in Greece. LINDQUIST, B., 1941, Experimentelle Untersu- chungen uber die Bedeutung einiger Landmol- lusken für die Zersetzung der Waldstern. К. Fysiogr. Lunds Läkaresällskaps Förhandlingar, |: 1-13. MASON, C. F., 1970a, Food feeding rates and as- similation in woodland snails. Oecologia (Berlin), 4: 358-373. MASON, С. F., 1970b, Snail populations, beech lit- ter production, and the role of snails in litter de- composition. Oecologia (Berlin), 5: 215-239. PETRUSEWICZ, K. & A. MACFADYEN, 1970, Pro- ductivity of terrestrial animals. Principles and methods. IBP Hand. 13 Blackwell, Oxford. PHILLIPSON, S., 1960, A contribution to the feed- ing biology of Mitopus morio F. (Phalangida). Journal of Animal Ecology, 29: 35—43. RICHARDSON, A. M. M., 1975a, Food, feeding rates and assimilation in the snail Cepaea nemo- ralis (L). Oecologia (Berlin), 19: 59-70. RICHARDSON, A. M. M., 1975b, Energy flux in a natural population of the land snail Cepaea ne- moralis. Oecologia (Berlin), 19(2): 141-164. RUSSELL-HUNTER, W. D., В. MEADOWS, М. AP- LEY 8 A. BURKY, 1968, On the use of a “wet- oxidation” method for estimates of total organic carbon in mollusc growth studies. Proceedings of the Malacological Society of London, 38: 1-11. RUSSELL-HUNTER, W. D. & D. E. BUCKLEY, 1983, Actuarial Bioenergetics of nonmarine mol- luscan productivity. In: The Mollusca 6: 463-503, ed. by W. D. Russell-Hunter, Academic Press, INC NAY RUSSELL-HUNTER, W. D., D. ALDRIDGE, J. TASHIRO & B. PAYNE, 1983, Oxygen uptake and nitrogenous excretion rates during overwin- ter degrowth conditions in the pulmonate snail, Helisoma trivolvis. Comparative Biochemistry and Physiology, 74A (3): 491—497. RUSSELL-HUNTER, W. D., A. BROWNE & D. AL- DRIDGE, 1984, Overwinter tissue degrowth in natural populations of freshwater pulmonate snails (Helisoma trivolvis and Lymnaea palus- tris). Ecology, 65(1): 223-229. SLOBODKIN, L.B., 1962, Energy in animal ecol- ogy. Advances in Ecological Research. Aca- demic Press. (Gragg, J.B.), |: 69-101. SLOBODKIN, L.B. & S. RICHMAN, 1961, Calories/ gm. in species of animals. Nature, 191:299. STAIKOU, A., M. LAZARIDOU-DIMITRIADOU & N. FARMAKIS, 1988, Aspects of the life cycle, pop- ulation dynamics, growth and secondary produc- tion of the edible snail Helix lucorum Linnaeus 1758 (Gastropoda Pulmonata) in Greece. The Journal of Molluscan Studies, 54: 139-155. STERN, G., 1968, Recherches sur le bilan éner- getique de la limace Arion rufus L. en période de croissance. Doctorat 3e cycle, Paris. STERN, G., 1975, Effet de la temperature sur la production et al consommation chez Agriolimax reticulatus (M.) en période de croissance, Bulle- tin Ecologique, V1:501-509. STERN, G., 1979, Bilans pondéral et énergétique de croissance et de reproduction chez Agriolimax laevis (Müller), Pulmonata, Limacidae. Bulletin de la Société Zoologique de France, 104(2): 147-161. TASHIRO, J., W. ALDRIDGE, & W. D. RUSSELL- HUNTER, 1980, Quantifiable artificial rations for molluscan grazing experiments. Malacological Review, 13: 87-89. WILLIAMSON, P., 1975, Use of Zn to determine the field metabolism of the snail Cepaea nemo- ralis L. Ecology, 56: 1185-1192. ZEIFERT, D. V. & S. V. SHUTOV, 1978, Role of certain terrestrial molluscs in the transformation of leaf litter. Ekologiya, 5: 58-61. ZEIFERT, D. V. & S. V. SHUTOV, 1981, The con- sumption of leaf litter by land molluscs. Pedobio- logia, 21: 159-165. Revised Ms. accepted 16 July 1989 Publication dates Vol. 28, No. 1-2 19 January 1988 Vol. 29, No. 1 28 June 1988 Vol. 29, No.2 16 Dec. 1988 Vol. 30, No. 1-2 1 Aug. 1989 AWARDS FOR STUDY AT The Academy of Natural Sciences of Philadelphia The Academy of Natural Sciences of Philadelphia, through its Jessup and McHenry funds, makes available each year a limited number of awards to support students pursuing natural history studies at the Academy. These awards are pri- marily intended to assist predoctoral and immediate postdoctoral students. Awards usually include a stipend to help defray living expenses, and support for travel to and from the Academy. Application deadlines are 1 March and 1 October each year. 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MIKKELSEN & RÜDIGER BIELER Biology and Comparative Anatomy of Divariscintilla yoyo and D. troglodytes, Two New Species of Galeommatidae (Bivalvia) from Stomatopod Burrows in Eastern Rn, Florida re В er EN Re SE VE Re OS IRA ROBERT T. DILLON, JR. — Karyotypic Evolution in ОЕ Snails. |. Genomic DNA Estimated by Flow - , а А A PRO EAN PRE Л... y ROBERT C. BAILEY Habitat Selection by a Freshwater Mussel: An Experimental Test ............. R. VITTURI 8 E. CATALANO Spermatocyte Chromosomes and Nucleolus Organizer Regions (NORs) in Tri- — colia Speciosa (Mühlfeld, 1824) (Prosobranchia, Archaeogastropoda) ......... A. STAIKOU & М. LAZARIDOU-DIMITRIADOU = | Feeding Experiments on and Energy Flux in a Natural Population of the Ed- | ible Snail Helix Lucorum L. (Gastropoda: Pulmonata: Stylommatophora) in Grogcel si e O Re Oe ES RIT PR O mek Se OL. 31, NO. 2 MCZ и. | JUN 06 1990 > TS ia $ a Be | HARVARD — NIVERSITY N ALACOLOGIA MALACOLOGIA Editor-in-Chief: ; GEORGE M. 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HICKMAN В, ов Berkeley University of Colorado Museum, Boulder } Participating Mens EDMUND GITTENBERGER JACKIE L. VAN GOETHEM Ñ Ds Secretary, UNITAS MALACOLOGICA Treasurer, UNITAS MALACOLOGICA _ Г Rijksmuseum van Natuurlijke Koninklijk Belgisch Instituut my Historie voor Natuurwetenschappen Leiden, Netherlands Brussel, Belgium Emeritus Members J. FRANCIS ALLEN, Emerita ROBERT ROBERTSON Environmental Protection Agency The Academy of Natural Sciences Washington, D.C. Philadelphia, Pennsylvania ELMER G. BERRY, NORMAN F. SOHL Germantown, Maryland U.S. Geological Survey Reston, Virginia Copyright © 1990 by the Institute of Malacology 1990 EDITORIAL BOARD J. A. ALLEN Marine Biological Station Millport, United Kingdom Е. Е. BINDER Museum d’Histoire Naturelle Geneve, Switzerland А. J. CAIN University of Liverpool United Kingdom P. CALOW University of Sheffield United Kingdom A. H. CLARKE, Jr. Portland, Texas, U.S.A. B. C. CLARKE University of Nottingham United Kingdom R. DILLON College of Charleston SC, U.S.A. C. J. DUNCAN University of Liverpool United Kingdom E. FISCHER-PIETTE Museum National d'Histoire Naturelle Paris, France М ЕВЕТТЕВ University of Reading United Kingdom E. GITTENBERGER Rijksmuseum van Natuurlijke Historie Leiden, Netherlands F. GIUSTI Universita di Siena, Italy A. N. GOLIKOV Zoological Institute Leningrad, U.S.S.R. S. J. GOULD Harvard University Cambridge, Mass., U.S.A. A. V. GROSSU Universitatea Bucuresti Romania Т. НАВЕ Тока! University Shimizu, Japan R. HANLON Marine Biomedical Institute Galveston, Texas, U.S.A. A. D. HARRISON University of Waterloo Ontario, Canada J. A. HENDRICKSON, Jr. Academy of Natural Sciences Philadelphia, PA, U.S.A. K. E. HOAGLAND Association of Systematics Collections Washington, DC, U.S.A. B. HUBENDICK Naturhistoriska Museet Göteborg, Sweden S. HUNT University of Lancaster United Kingdom R. JANSSEN Forschungsinstitut Senckenberg, Frankfurt am Main, Germany (Federal Republic) R. N. KILBURN Natal Museum Pietermaritzburg, South Africa M. A. KLAPPENBACH Museo Nacional de Historia Natural Montevideo, Uruguay J. KNUDSEN Zoologisk Institut & Museum Kobenhavn, Denmark A. J. KOHN University of Washington Seattle, U.S.A. Y. KONDO Bernice P. Bishop Museum Honolulu, Hawaii, U.S.A. A. LUCAS Faculte des Sciences Brest, France C. MEIER-BROOK Tropenmedizinisches Institut Tübingen, Germany (Federal Republic) H. K. MIENIS Hebrew University of Jerusalem Israel J. E. MORTON The University Auckland, New Zealand J. J. MURRAY, Jr. University of Virginia Charlottesville, U.S.A. R. NATARAJAN Marine Biological Station Porto Novo, India J. OKLAND University of Oslo Norway T. OKUTANI University of Fisheries Tokyo, Japan W. Е. PARAENSE Instituto Oswaldo Cruz, Rio de Janeiro Brazil J. J. PARODIZ Carnegie Museum Pittsburgh, U.S.A. W. Е. PONDER Australian Museum Sydney R. D. PURCHON Chelsea College of Science & Technology London, United Kingdom OZ Academia Sinica Qingdao, People's Republic of China N. W. RUNHAM University College of North Wales Bangor, United Kingdom S. G. SEGERSTRÂLE Institute of Marine Research Helsinki, Finland G. ALAN SOLEM Е. STARMUHLNER Zoologisches Institut der Universität Wien, Austria У. 1. STAROBOGATOV Zoological Institute Leningrad, U.S.S.R. W. STREIFF Universite de Caen France J. STUARDO Universidad de Chile Valparaiso T. E. THOMPSON ЭТЮЧЕВ Museum National d’Histoire Naturelle Paris, France R. D. TURNER Harvard University Cambridge, Mass., U.S.A. W. $. $. van BENTHEM JUTTING Domburg, Netherlands J. A. van EEDEN Potchefstroom University South Africa N. H. VERDONK Rijksuniversiteit Utrecht, Netherlands B. R. WILSON Dept. Conservation and Land Management Netherlands, Western Australia H. ZEISSLER Leipzig, Germany (Democratic Republic) A. ZILCH Forschungsinstitut Senckenberg Frankfurt am Main, Germany (Federal Republic) MALACOLOGIA, 1990, 31(2): 229-236 TIDAL MICROGROWTH BANDS IN SIPHONARIA GIGAS (GASTROPODA, PULMONATA) FROM THE COAST OF COSTA RICA О. J. Crisp,’ J. G. Wieghell? & С. A. Richardson? ABSTRACT Siphonaria gigas growing on the coast of Costa Rica under a semi-diurnal tidal regime lays down one microgrowth band per tide. This relationship was used to measure the rate of incre- mental growth at the anterior and posterior margins of the shell. The growth rate was somewhat irregular, and the anomalies at each margin were shown probably to compensate each other. Barnacle cover probably reduced growth rate. An approximate curve of diameter increase against time, assuming the Bertalanffy equation, is given. Key words: Siphonaria, growth rates, microgrowth bands. INTRODUCTION Within the calcareous skeletons of many living marine invertebrates occupying the in- tertidal zone or shallow sublittoral are minute banding patterns, known as microgrowth bands. These may best be seen by making acetate peel replicas of a polished and etched section of the shell cut along the direction in which additional shell is laid down during its growth. These microgrowth bands appear as a series of light and dark bands when viewed under the microscope by transmitted light. The darker bands are usually narrower and have been termed “growth bands” while the lighter intervening areas were termed “growth increments” (Richardson et al., 1979) al- though both bands and increments represent additions to growth of the shell. Such tidal banding patterns have been demonstrated in a variety of animal groups, quite independently of their phylogenetic ori- gins. They were first demonstrated by Evans (1972, 1975) in the Pacific cockle Clinocar- dium nuttallii, and are perhaps most clearly expressed in other members of the Cardia- cea. Richardson and his co-workers’ studies that underlie our present understanding of the endogenous and exogenous nature of tidal bands, their relation to other environmental factors, and their interaction with spring and neap tidal changes were carried out with the European cockle, Cerastoderma edule, under the semi-diurnal tidal regime of northwestern Europe (Richardson et al., 1979, 1980a, b, 1981). The few gastropods studied so far con- tain tidal increments in the coiled whorls of the shell in typical forms or, in the case of limpets, along the corresponding region, viz. outer sides of the shell (Ekaratne & Crisp, 1982, 1984). The evidence for tidal bands in the primitive polyplacophoran molluscs is less certain, but a regular 28-day periodic series of patterns were observed in New Zealand chi- tons by Jones & Crisp (1985) suggesting a tidal periodicity over the 14-day lunar cycle. Barnacle growth, analysed by Bourget & Crisp (1975a, 1975b, 1985) in Balanus bal- anoides, also was found to show periodic growth with tidal banding in the shell, and sim- ilar banding patterns were demonstrated also in Elminius modestus (Crisp & Richardson, 1975). Of particular interest are the marine pulmo- nates. Pulmonates are believed to have evolved air breathing from the main stock of marine gastropods to fit them to life on land. Siphonaria browses on rocks in the littoral zone and has evolved by convergent evolu- tion a shell morphology like that of archaeo- gastropod limpets and a similar behaviour pattern (Morton, 1968; Barnes, 1982). The question arises whether shell growth occurs in increments separated by tidal bands or whether it grows more or less continuously without reference to tides. School of Animal Biology [now Biological Sciences], University College of North Wales, Bangor, Gwynedd, United Kingdom LL57 2UW. 267, Etwall Rd., Hall Green, Birmingham, United Kingdom B28 OLF 3School of Ocean Sciences, Marine Science Laboratories, Menai Bridge, Anglesey, United Kingdom LL59 SEH. All correspondence and reprint requests to Dr. C. A. Richardson, 230 CRISP ЕТ AL. TABLE 1. Positions of sites and conditions of growth in three groups of Siphonaria gigas. Band-dating Date of Group no. Coast technique marking 1 P.M.E. file-marked 5.V11.85 identity no. 2 P.M.W. identity no. 5.V11.85 only 3 P.M.W. identity no. 5.V11.85 only P.M.E.: Punta Mala East; P.M.W.: Punta Mala West MATERIALS AND METHODS Siphonaria gigas Sowerby, 1825, was col- lected from two shores on the west coast of Costa Rica, Punta Mala West and Punta Mala East, Guanacaste Province (Ortega 1985, 1986; Sutherland & Otega, 1986), from mid to high level of the intertidal zone. The condi- tions of growth and site details of three groups of animals used in this investigation are sum- marised in Table 1. The specimens of group 1 only were “file-marked” at the growing edge adjacent to the rock surface at the time of low water on 5 July 1985, without removal from the rock. Simultaneously, a small plastic tag was fixed to the side of the shell with ar- aldite for individual identification. Each indi- vidual of groups 1, 2 and 3 were so labelled, but only those of group 1 were also file marked. A file mark in the European arche- gastropod limpet Patella vulgata causes a cleft to be formed that can be related to a particular growth band, giving it the relevant date of the edge of the shell at that point. Ekaratne & Crisp (1984) described alternative methods of “band dating” shells and found file marking to be one of the more reliable techniques. However, they noted that it usu- ally reduced shell growth rate for a number of days afterwards so that one or two bands im- mediately after file marking might be lost com- pletely. Similarly, the file marking procedure was found to result in a slight growth check in S. gigas, which could be seen as a weak ring running around the surface from the original file mark, and as a cleft seen in section (Fig. 1). Similarly, some of the shells that had been simply given an identity tag also appeared to have been affected by the disturbance, pro- ducing a small cleft. Since these individuals had neither been removed from the rock nor filed, the disturbance was minimal and in No. of days Date of between marking Chthamalus collection and collection presence 17.V111.85 44 absent 17.V111.85 44 absent 17.V111.85 44 present some individuals it was not possible to identify such a cleft so that the bands could not be dated. After having been collected on 17 August 1985, the animals were immediately killed and the tissues removed from the shell. On arrival in the United Kingdom, any adherent barna- cles or debris were removed from the outside of the shell, the tag was removed, the shells scrubbed, dried and labelled. The identity number was written in indelible ink on the in- side of the shell, and any external ridge as- sociated with the file mark or attachment ofthe tag was also outlined with an arrow pointing to it (Fig. 2). Thus, the disturbance mark or cleft in the acetate peel could be related to the appropriate band seen in section. Each shell was embeddded in “metaset” resin, left for at least 15 h to harden, and cut by hacksaw along its maximum diameter. It was smoothed and polished as recommended by Richardson et al. (1979) using a series of increasingly fine abrasives (340, 120 wet and dry trimite paper), and polished for 30 seconds on cloth soaked in household metal polish “Brasso.” It was ‚ washed in mild detergent and finally etched for 20 minutes in a 1% “Decal,” a formic-acid- based histological decalcifying fluid. After a further rinse in distilled water, it was air dried for 2-3 hours and the section was ready for replication. The appropriate size of acetate sheet (replicating material) was cut out, wetted briefly with ethyl acetate and laid on the sec- tion with air bubbles eliminated as far as pos- sible. The section and replica were placed un- der a plastic box to reduce the rate of evaporation of ethyl acetate. After at least 15 minutes the replica was peeled off and kept flat by holding between coverslip and microscope slide. Peels are best viewed in a low power phase contrast microscope in air, not in mount- ing medium. TIDAL BANDS IN SIPHONARIA 231 FIG. 1. An enlarged photograph of the aceıate peel replica of Siphonaria gigas in the region of growth. GC: cleft indicating growth check. Parallel dark lines indicate tidal bands seperated by increments. The growth bands are superimposed on light and dark patches caused by varied orientations of crystallites which are generally orthogonal to the direction of the growth bands and increments. Counting Bands Where possible the cleft or growth check clearly associated with a file mark or thought to be caused by disturbance through tagging was identified. The first band at this mark was taken as the datum for counting the number of increments between the check and shell edge. As can be seen in Figure 2, growth is not symmetrical around the shell, but the an- terior end becomes steeper than the poste- rior, as in most limpets. Thus, any section in the anterior-posterior plane exposes two growth regions, the anterior being shorter than the posterior. Assuming that the shell in- creases all round by concurrent increments, the band width should be shorter along the anterior half but the number should be the same. Band counts were made from the growth checks to the anterior (A) and poste- rior (P) margins of the shell, and each count was repeated. From the band counts and as- sociated statistical tests we sought the an- swer to the following questions. 1. Did the anterior and posterior profiles manifest the same number of bands? 2. Were the bands laid down at tidal intervals? 3. Were growth rates influenced by spring or пеар tidal periods? 4. Did barnacle cover influence growth rate? 5. Did locality influence growth rate? Measurements Before embedding the shells in resin, each shell was scrubbed clean, dried and weighed to the nearest 10 mg (W) and its longer diam- eter (D) and height (H) measured using ver- nier calipers within 0.1 mm. The total growth between the disturbance mark and the ante- rior and posterior margins was measured us- ing a calibrated eyepiece graticule to an ac- curacy of +1%. Tidal data The Tidal Institute at Bidston kindly sup- plied tidal data for the Standard Port of Pan- ama (Balboa) for July 1985. A normal semi- diurnal pattern of tides operates at Punta Mala, with a maximum range of 5 m at springs and a minimum of 2 m at neaps. There were 83 tidal emersions between 5 July and 17 Au- gust 1985. 232 CRISP ET AL. FIG. 2. (a) Side view of Siphonaria gigas. Arrow points to disturbance mark. NG: new growth after disturbance, t: marking tag. (b) View of the interior of the shell showing identity (no. 3) and direction of saw cut along the anterior (A) and posterior (P) direction passing through the apex (black dot). RESULTS 1. Shell Measurements A comparison of the relationships between shell weight, shell diameter and shell height revealed no significant difference among the three groups of shells described in Table 1. In all cases, volume calculated as V = rD°H/12 rose with the weight (W), not significantly de- viating from isometry (Table 2). The mean val- ues of weight/volume was 0.9248 + 0.0152, but shell shape changed significantly with in- crease in size, as shown in Table 2. The av- erage angle subtended by the shell to the hor- izontal (9) was obtained as 6 = Tan ' (2H/D), and Tan 6 increased with size as expected, the shell becoming taller. The mean value of 6 over all individuals was 36.6° with 95% confi- dence limits 35.7°-37.5°. 2. Microgrowth Bands In many shells it was far from easy to iden- tify the growth check with certainty. Only in those shells where the distance measured from the external ridge to the edge of the growing tip corresponded with the distance of the cleft in the replica to the tip of the replica were the observations on numbers of bands included. The number of specimens giving countable bands and fulfilling the above crite- ria were six with file marks from Punta Mala East, four from Punta Mala West in the non barnacled area, and four from Punta Mala West in the barnacled area. The total number was thus 14, which was sufficient to deter- mine the periodicity of the banding, but insuf- ficient to validate such other questions as dif- ferences between sites, influence of barnacle settlement, and effect of spring and neap tidal periods. Counts of Microgrowth Bands The bands of the 14 selected shells were each counted along the anterior and posterior margins twice, except for two shells where the posterior margin was not accurately count- able (Table 3). If from all values for first readings (Count 1) are subtracted those of Count 2 an estimate of the reliability of counting can be made. There are 26 values, and the matched pairs t test for 25 degrees of freedom gives t = 0.64 (N.S.). There is therefore no significant differ- ence between the two counts (p = 0.53). The standard error of the difference be- tween count 1 and Count 2 is 1.223 so that any count based on the mean of Count 1 and 2 can be relied upon to have a standard error of only + 0.864 and confidence limits + 3.7 of the average count observed, when p = 0.05. Similar “matched pairs” t test was applied to the 12 average count differences between ‚ the counts at the anterior and posterior mar- gins. The probability that counts at both mar- gins could have come from the same popula- tion of values was 0.74, p = 0.45, showing that the results were not significantly different and that each margin could be regarded as a replicate count. When all 52 observations were assembled they gave a mean band number of 81.04 with 5% confidence limits lying between 80.31 and 81.77. This result can be compared with the theoretical value for one band per tide of 83.00, or of one band per day of 44.00. Though significantly less than 83.00 (t = 5.35, p = 0.0001) the defi- ciency from an exact tidal periodicity is only 2.4%. This is of the magnitude to be expected as a result of the disturbance caused by the TIDAL BANDS IN SIPHONARIA 233 TABLE 2. Changes in shell characteristics with size (33 individuals). SSS Derived formula Students t value for 33 Expected index for deviation Regression individuals for isometry from expectation Significance Log V on Log W 1,09 W0 5 1.000 1.29 Not Sig. = Log H on Log V TABI 0.333 + 5.49 Sig. <0.0001 Log H on Log W ВМ" 0.333 + 4.60 Sig. <0.0001 Log D оп Log V 22.10V. > 0.333 -5.48 Sig. <0.0001 Log D on Log W 22.15W. 0.333 4.10 Sig. <0.0001 LogH on Log D Os DE 1.000 +4.09 Sig. <0.0001 Tan 6 on W 0.660 + 0.0537W 0.000 + 5.62 Sig. <0.0001 TABLE 3. Band counts in the anterior and posterior margins of shells of Siphonaria gigas specimens grown in two natural environments. Number of bands counted Number of bands counted Site and Specimen in ‘A’ margin in ‘P’ margin conditions number count | count Il count | count II P.M.E. no G 82 80 80 81 Chthamalus E 81 82 82 84 B 83 82 82 79 O 80 80 79 80 С 82 81 78 79 В 83 82 83 83 Р.М.Е. по 4 78 78 u — Chthamalus 5 80 80 ТР 79 6 82 83 80 80 8 81 81 80 81 P.M.W. I 79 81 83 82 heavy S 81 82 82 82 Chthamalus N 82 82 84 83 F 81 82 — — (‘A’) Anterior and ('P') Posterior margins date marking and is clearly not daily but tidal banding as with many other marine molluscs. Growth Rates The longer profile at the posterior end of the shell implies a greater rate of growth than at the shorter anterior profile. The average total increment over 83 tidal cycles was indeed slightly higher at the posterior end 1.46 + GROWTH (mm) 0.13 mm than at the anterior (1.41 + 0.12 mm) but not significantly so. The two sites without barnacles present gave growth rates that did not differ signifi- cantly, showing increments in length of each margin at Punta Mala East of 0.0339 and at Punta Mala West of 0.0401 mm day ‘. At Punta Mala West in the presence of Chtha- malus the increment in length averaged at 0.0305 mm day '. When the growth rates at NUMBER OF TIDES FIG. 3. Details of growth of a single individual Si- phonaria gigas with very clear microgrowth lines. At anterior border, (A) and at posterior border (Г). N: neap tides, S: spring tides. the two Chthamalus-free shores were com- bined and averaged (0.036 mm day ') they were not significantly higher than that at 234 CRISP ET AL. Co rn GROWTH ОЕ BOTH SHELL MARGINS (mm) NUMBER OF TIDES FIG. 4. Sum of growth at anterior and posterior bor- ders of the same individual (Fig. 3) showing decel- eration of growth rate with age. N: neap tide, S: spring tide. Punta Mala West where Chthamalus was present (t = 1.146, p = 0.25). Similarly, a comparison of Punta Mala West shores with and without Chthamalus gave t = 1.37,p = 0.20, again a figure not usually regarded as significant. However, as measured, the growth rate in the presence of Chthamalus appears to have been reduced by 24%. К should be noted that the growth rates of each side of the shell when added together and adjusted for shell slope (Ekaratne & Crisp, 1984) give the growth rate of the shell in height or diameter, which are the measure- ments usually quoted. However, a detailed measurement of both borders, anterior (A) and posterior (P) of shell N, giving the incre- ment over each of two tidal cycles from the shell edge to 83 bands behind, as reproduced in Figure 3, shows that growth is far from uni- form. It will be seen that both borders give sharp increases in length, and then slow down. Although A and P borders are coarsely correlated positively, since both are growing their random fluctuations appear to take place independently and without any common ref- erence to the tidal cycle. Furthermore, if the increments of the A and P borders are summed and A + P is plotted against the number of the tidal event (Fig. 4), the resulting plot appears more regular. In order to test the possibility of compensatory growth, the incre- ments at each border were listed and the mean increment subtracted to give the esti- mated acceleration or deceleration of growth for that tidal cycle at each border. These 30 20 DIAMETER (mm) O, 12 24 AGE IN MONTHS FIG. 5. Growth curve of a sample of four Siphonaria gigas in barnacled area based on tidal bands. L = bod —e-“) Lo = 27:2 mm, К — 000205 day '. Rate at 17 тт = 0.047 mm day "' anomalies were then regressed against each other. They gave a negative correlation coef- ficient of 0.281 for 39 degrees of freedom and a probability of random variation of only 0.076 in support of compensatory growth. Thus, it seems likely that the apparently random fluc- tuations at the A and P borders are not en- tirely random, but negatively correlated. When one border grows rapidly, growth at the other border is suppressed so that the total growth is more regular at either border. After such an episode, the roles reverse and the other border catches up. A similar compensa- tion mechanism was noted by Crisp & Patel (1967) in regard to the growth of the lateral plates of the barnacle Elminius modestus. The general form of the growth curve, if the irregularities are ignored, is asymptotic, prob- _ ably close to the Bertalanffy model. However, if an attempt is made to determine the con- straints of the Bertalanffy equation using the plot of dL/dt against size L (see Crisp, 1985), these irregularities make the differentiation of L by t almost impossible. By using two values of dL/dt from the sum A + P = L over the whole 83 increments for the largest and smallest shells, we obtained a not very ap- proximate equation for Siphonaria gigas growth in an area with barnacles present (Fig. 5). By measuring the average angles of the anterior (A) and posterior (P) margins (d) the sum of the growth at each has been con- verted to diameter (D) increase through the relation: dD = (dA + dP) Cos 6 TIDAL BANDS IN SIPHONARIA 235 where 0 = Tan ' (2H/D) and 6, its mean value, was 36.6°, Cos # = 0.803. DISCUSSION Microgrowth bands with a tidal periodicity have been established in certain barnacles (Bourget & Crisp, 1975a, b; Crisp & Richard- son, 1975), bivalves (Evans, 1972, 1975; Richardson et al., 1979, 1980a, b, 1981; Richardson, 1987), and probably in Poly- placophora (Jones & Crisp, 1985). All these are marine animals inhabiting the intertidal zone. Crisp (1989), reviewing the phenome- non, gave various lines of evidence to sug- gest that harder and more perfectly crystalline parts of the shell comprised the bands and that these formed when the body fluids were temporarily at a lower pH due to an accumu- lation of carbon dioxide and perhaps organic acids during emersion. All shell-secreting in- vertebrates exposed to the air and closed temporarily to avoid water loss, would be likely to experience acidosis and thus would slow down or prevent secretion of calcium carbonate. The siphonarian gastropods differ from all the above groups in being regarded as be- longing to a group, the subclass Pulmonata, superorder Basommatophora, that has be- come adapted to terrestrial life. Typically the mantle cavity has reduced external access by a narrow pore, its vascularised roof functions as a lung, the animal has lost the ctenidia and operculum, and it lays a shelled egg. How- ever, Siphonaria itself is only partially modi- fied. It retains or re-develops aquatic respira- tion through the siphon situated on the right side, it has secondary branchial lamellae on the roof or the mantle cavity and has retained a pelagic larval stage. The strong marine af- finity has led, in the past, to the Siphonariidae being regarded as evolved from marine opisthobranchs and classified as a family of the tectibranchs. Whatever the origin of Siphonaria, their pa- telloid form and adherent physiology (Morton, 1968) are so closely similar to those of the patelloid archegastropods that the presence of microgrowth lines in the shell of Siphonaria are likely to have been produced by the same factors as in Patella. The need to retain water when closely adhering to the rock and the consequent absence of respiratory exchange at the time of low water would similarly give rise to a fall in pH since there is then no ef- fective air breathing mechanism at work. Thus, it is not surprising that they too should |ау down shell bands in synchrony with tidal emersion. ACKNOWLEDGEMENTS We thank Dr. Sonia Ortega for supplying the material on which this study was based together with the environmental information given in Table 1. One of us (D.J.C.) wishes to thank the Leverhulme Trust, which provided him with financial support during the course of this work. Dr. N. W. Runham read and im- proved the text. LITERATURE CITED BARNES, R. D. 1982. Invertebrate zoology. Holt- Saunders Japan, Tokyo, 1089 pp. BOURGET, E. & D. J. CRISP, 1975a. Factors af- fecting deposition of the shell in Balanus bal- anoides (L). Journal of the Marine Biological As- sociation of the United Kingdom, 55, 231-248. BOURGET, E. & D. J. CRISP, 1975b. An analysis of the growth bands and ridges of barnacle shell plates. Journal of the Marine Biological Associa- tion of the United Kingdom, 55, 439-461. CRISP, D. J. 1985. Energy flow measurements. In: Methods for the Study of Marine Benthos (Eds. N. A. HOLME & A. D. MCINTYRE). Pp. 284-372 Oxford, Blackwell. CRISP, D. J. 1989. Tidally deposited bands in shells of barnacles and molluscs. In: Biomineral- isation (Ed. R. CRICK). New York, Plenum Press. CRISP, D. J. & Е. BOURGET, 1985. Growth in bar- nacles. Advances in Marine Biology, 22, 199— 244. CRISP, D. J. & В. PATEL, 1967. The influence of surface contour on the shapes of barnacles. Pro- ceedings of the Symposium of Crustacea, Marine Biological Association of India, Part Il, 612-629. CRISP, D. J. & C. A. RICHARDSON, 1975. Tidally produced internal bands in the shell of E/minius modestus. Marine Biology, 33, 155-160. EKARATNE, S. U. K. & D. J. CRISP, 1982. Tidal micro-growth bands in intertidal gastropods, with an evaluation of band-dating techniques. Pro- ceedings of the Royal Society of London, B, 214, 305-328. EKARATNE, S. U. K. & D. J. CRISP, 1984. Sea- sonal growth studies of intertidal gastropods from shell microgrowth band measurements, including a comparison with alternative methods. Journal of the Marine Biological Association of the Untied Kingdom, 64, 183-210. EVANS, J. W. 1972. Tidal growth increments in the cockle Clinocardium nuttalli. Science, 176, 416— 417. 236 CRISP ET AL. EVANS, J. W. 1975. Growth and micromorphology of two bivalves exhibiting non-daily growth lines. In: Growth rhythms and the History of the Earth's rotation (Eds. G. D. ROSENBERG & S. K. RUN- CORN). Pp. 119-134. London, John Wiley & Sons. JONES, P. & M. CRISP, 1985. Microgrowth bands in chitons: evidence of tidal periodicity. Journal of Molluscan Studies, 51, 133-137. MORTON, J. Е. 1968. Molluscs. Hutchinson Uni- versity Library London, 244 pp. ORTEGA, S. 1985. Competitive interactions among tropical intertidal limpets. Journal of Experimen- tal Marine Biology and Ecology, 90, 11-23. ORTEGA, S. 1986. Fish predation on gastropods on the Pacific coast of Costa Rica. Journal of Experimental Marine Biology and Ecology, 97, 181-191. RICHARDSON, C. A. 1987. Tidal bands in the shell of the clam Tapes philippinarum, (Adams & Reeve, 1850). Proceedings of the Royal Society of London B, 230, 367-387. RICHARDSON, C. A., D. J. CRISP & N. W. RUN- HAM, 1979. Tidally deposited growth bands in the shell of the common cockle, Cerastoderma edule (L). Malacologia, 5, 277-290. RICHARDSON, С. A. D. J. CRISP & N. W. RUN- HAM, 1980a. Factors influencing shell growth in Cerastoderma edule. Proceedings of the Royal Society of London B, 210, 513-531. RICHARDSON, С. A. D. J. CRISP & N. W. RUN- HAM, 1980b. An endogenous rhythm in shell deposition in Cerastoderma edule. Journal of the Marine Biological Association of the United King- dom, 60, 991-1004. RICHARDSON, С. A. D. J. CRISP & N. W. RUN- HAM, 1981. Factors influencing shell depostion during a tidal cycle in the intertidal bivalve Ceras- toderma edule. Journal of the Marine Biological Association of the United Kingdom, 61, 465-476. SUTHERLAND, J. P. & S. ORTEGA, 1986. Com- petition conditional on recruitment and temporary escape from predators on a tropical rocky shore. Journal of Experimental Marine Biology and Ecology, 95, 155-166. Revised Ms. accepted 21 September 1989 MALACOLOGIA, 1990, 31(2): 237-248 THE NUMBERS OF FRESHWATER GASTROPODS ON PACIFIC ISLANDS AND THE THEORY OF ISLAND BIOGEOGRAPHY Alison Haynes School of Pure and Applied Sciences, University of the South Pacific, PO. Box 1168, Suva, FUI. ABSTRACT The freshwater gastropod fauna of the Pacific islands of Веда, Vanuabalavu, Waya, Rotuma (Fiji), Upolu, Savai'i, Tutuila (Samoa), Tongatapu, Vava'u (Tonga), Rarotonga (Cook Islands), New Georgia (Solomon Islands), Guam, Truk and Ponepe (Micronesia) is described. Thirty eight species were found; 26 species belonged to the Neritidae, 10 to Thiaridae, and one each to Assimineidae and Planorbidae. Using multiple regression analysis, the numbers of species on these and 11 other Pacific islands were shown to be correlated with the water area on the island and the distance the island was from a source of freshwater gastropods (accounting for 92% of the variation). Distance by itself was not a significant contributor. Islands with a small area of water showed a steeper species-water area curve, and the number of species on these islands was more correlated with distance than to water area. This was probably due to a higher extinction rate brought about by the drying up of the limited number of habitats. Key words: freshwater, gastropods, Pacific islands, island biogeography. INTRODUCTION Faunal studies of angiosperms, birds and land snails in the Pacific have documented the ranges and distributions of the species in these taxa and have revealed examples of endemism and of species radiation (Car- Iquist, 1974; Diamond, 1984; Solem, 1959). These studies have also been used in discus- sions of the theory of island biogeography de- veloped by MacArthur & Wilson (1967). This theory suggests that because the immigration rate to near islands is greater than that to more distant islands and because the extinc- tion rate is greater on smaller islands than on larger islands, the equilibrium number of spe- cies tends to increase with island area. In the past, freshwater snail diversity has been dis- cussed in relation to this theory, with lakes and ponds being considered as islands of wa- ter isolated by land barriers (Lassen, 1975; Aho, 1984). The aims of this work were to establish what species of freshwater gastropods are present on Pacific islands and to find if the island faunas, some of which had already been described (Haynes, 1985, 1988a; Star- mühlner, 1976), supported the theory of is- land biogeography. 237 METHODS Freshwater Gastropod Survey From 1983 to 1987, freshwater gastropods were collected from the islands of Bega, Ro- tuma, Vanuabalavu, Waya (Fiji); Guam; Truk (Federated States of Micronesia); Savarïi (Western Samoa); New Georgia (Solomon Islands); Rarotonga (Cook Islands) (Fig 1). The fauna of these islands is described for the first time. Collections were also made from Ponepe (Federated States of Micronesia); Upolu (Western Somoa); Tutuila (American Samoa); Tongatapu, Vava'u (Tonga) (Table 1). All islands are within the tropics. Guam is the most northerly at 14°N and Rarotonga is the most southerly at 22°S. Freshwater gastropods were collected by hand from rocks, boulders and vegetation or were sieved with a 1 mm mesh from gravel and mud from streams, rivers and pools. Sampling took place both near the coast and inland to ensure that the gastropods found were representative of the whole fauna. Each site was searched for at least an hour, and all collections were made when the volume of water flowing in each stream was low to nor- mal. 238 HAYNES | KAUAI® | ——— 150° 160 170° iv в 160° %» 20° “GUAM A A НЧ 10° FIJ1 ISLANDS -TRUK -PONEPE B Bega E G Gau К Kadavu О Ovalau T Taveuni O У Vanuabalavu NEW W Waya GUINEA NEW GEORGIAS N Ñ == GUADALCANAL la 10° -ROTUMA eSAVAII \ UPOLU -TUTUILA $ VANUA BL A | EFATE a | ` | NEW ve CALEDONIA Es | VITILEVUg-O. ' Bok eyes TAHITIS o 20 *RAROTONGA -VAVAU | -ТОМСАТАРИ FIG. 1. Pacific islands from which collections of freshwater gastropods have been made. Identification of the snails followed Riech (1937), Starmühlner (1970, 1976), and Haynes (1984). Water temperature was recorded, and wa- ter samples were collected on New Georgia, Upolu, Saval'i, Tutuila, Tongatapu and Vav'u. These were analysed for pH, total ions (us cm ') and hardness mg CaCO, 1 ') by the Institute of Natural Resources, University of the South Pacific. Some collections were made on islands that were visited not prima- rily for collecting gastropods; on these islands no water samples were taken. All gastropod collections are housed in the Biology Department, University of the South Pacific. Island Biogeography Data for the 14 islands investigated are pre- sented in Table 2, along with data already published for other Pacific islands. The is- lands previously investigated are Viti Levu (Fiji) (Haynes, 1985); Vanua Levu, Ovalau, Gau, Kadavu, Taveuni (Fiji) (Haynes, 1988a); Guadalcanal (Solomon Island), Efate (Van- uatu), Tahiti (Starmühlner, 1976); New Cale- donia (Starmühlner, 1970); and Kauai (Ha- wali) (Burch & Patterson, 1971; Maciolek, 1978). Stream length was estimated by measuring the length of all streams and rivers on 1: 50,000 or 1:25,000 government maps of the islands. The water area was estimated by multiplying the stream length by a mean river ‚or stream width of 10-50 m (depending on the island size) and by adding the area of standing water to it. The large, geologically old islands of New Guinea, New Caledonia and Viti Levu were considered to be the most likely sources of freshwater immigrants to the islands, so that the distances in Table 2 were measured from the nearest of these three islands to the island in question. The three large islands together with nearby islands form three generally ac- cepted biogeographical subregions of the Pa- cific islands (Thorne, 1963). The source is- lands possessed all freshwater gastropod species found on the smaller islands in their regions, with the exception of endemic spe- cies. Apart from Kauai (Hawaii), the endemics GASTROPODS ON PACIFIC ISLANDS 239 TABLE 1. Study Sites N zz Micronesia 1. GUAM. Largest island in Micronesia. Formed from the union of two volcanoes. Yling River, Cetti and Asafines streams were sampled. 2. TRUK (Moen). Moen is one of the many islands in the Truk Lagoon. Winchen River and several small streams near the Continental Hotel were sampled. 3. PONEPE. A rugged island with high rainfall. Nanepil, Lehnmesi and Pilenkiepu rivers and Enipas Stream were sampled. The collections were made by John Maciolek and John Ford (Maciolek & Ford, 1987), who assisted the author with collections on Guam and Truk. Solomon Islands 4. NEW GEORGIA. A high volcanic island. Sampled along the length of Puha and Borora rivers. Western Samoa 5. SAVAT'A. Streams are confined to the south coast because of extensive lava fields on the north coast. Latolo Plantation Stream, Sili Village Stream, Mata'avai Pool, Asago Spring, and Sapavai'i Water Hole were sampled. 6. UPOLU. A high volcanic island. Sampled Fallefa Falls, Le Mafa Pass Stream, Mulivai Stream, and along the Vaisigano River. American Samoa 7. TUTUILA. Volcanic with short streams. Sampled Alofau, Lemafa Saddle and Le'ele streams, and Pala Lagoon. Tonga 8. TONGATAPU. A coral island with no running water. Sampled coastal and inland ponds. 9. VAVA’U. An elevated limestone cluster with no running water. Sampled pools and Lake Tuanuku. Cook Islands 10. RAROTONGA. The only true volcanic island in the Cook Islands. Sampled Avatiu, Vaimanga and Avana streams and taro patches. (Lower courses of all streams were dry in September 1983.) Fiji 11. BEQA. 14 km offshore from the main island of Viti Levu. Sampled the length of the stream at Naceva and in Naduruvesi Creek. 12. WAYA. In the Yasawa group. Sampled the two streams in the Yolobe area. 13. VANUABALAVU. Largest island in the northern Lau group. Northern part uplifted coral, southern part volcanic. Sampled the two streams near Lomolomo. 14. ROTUMA. An isolated volcanic island 500 km north of Viti Levu. The rock is porous, and there are no permanent streams. Wells and taro patches were sampled. were Fluviopupa brevior on Efate and Mel- anoides paxa and Melanoides peregrina on Upolu. New Caledonia, the source island for Efate, has three species of Fluviopupa that could have given rise to Fluviopupa brevior. Melanoides is a genus that shows much vari- ation within species, and the isolation on Upolu of one or more of the four Melanoides species from the source island Viti Levu could have given rise to Upolu’s two endemic species. The freshwater gastropods on Kauai, like most taxa in the Hawaiian group, show con- siderable speciation. It has eight endemic freshwater gastropod species. Four of these, Neritina granosa Sowerby, N. vespertina Sowerby, Clithon cariosus (Wood), C. neglec- tus (Pease), probably arose from species ar- riving from Southeast Asia or New Guinea. The four Lymnaeidae endemics (Erinna new- combi, E. aulacospira, Pseudisidora rubella and P. producta) probably had their origins in America, Melanoides tuberculata, Tarebia granifera (found elsewhere on Pacific islands), and Ferrissia sharpi probably arrived accidentally in recent times whereas Galba viridis was introduced from Asia about 1890 240 HAYNES TABLE 2. The 25 Pacific islands arranged according to area with the data used in multiple regression analysis. Stream Water No. of Area Height Distance length area species (km?) (m) (km) (km) (km?) Island y X; Xo Хз X, X, New Caledonia 30 16750 1618 source 3320 166 Viti Levu 31 10429 1323 source 2585 136 Vanua Levu 26 5556 1032 60 1230 62 Guadalcanal 24 5302 2330 200 1855 93 Saval' 11 1709 1856 800 300 16 New Georgia 20 1470 843 200 1080 54 Kauai 12 1432 1598 (6200) 604 83 Upolu 15 1114 ak) 840 325 17 Tahiti 15 1042 2241 2440 139 37 Efate 18 887 646 500 370 22 Guam 11 541 406 1800 122 2.00 Taveuni 15 470 864 10 483 11 Kadavu 114 411 838 85 398 6 Ponepe 11 334 772 1400 270 4 Tongatapu 3 259 19 740 0 0.25 Gau 16 140 750 62 197 2 Tutuila 13 187 652 1000 128 1.8 Vava'u 1 118 179 800 0 0.02 Ovalau 20 101 626 1174 105 Wess Rarotonga 3 67 653 2400 87 0.9 Rotuma 1 47 256 500 0 0.01 Vanuabalavu A 38 290 106 10 0.05 Bega 13 35 439 14 37 1.9 Truk (Moen) 4 19 369 1300 6 0.03 Waya 9 17 580 46 20 0.20 (Burch & Patterson, 1971; Maciolek, 1978). Therefore, inthe case of Kauai, distance from a source island is irrelevant. К was thought that little bias was introduced by using Starmühlner's figures for New Cale- donia, Guadalcanal, Efate and Tahiti. He col- lected from Upolu and Tutuila (Samoa) in 1985 (Starmühlner, 1986) and reported 23 species (one doubtful), which compares fa- vorably with the 22 species | found in 1987. Bishop Museum shell collections of fresh- water gastropods from Pacific islands were studied in 1985, and | undertook a revision of their nomenclature. The Bishop Museum col- lections, which are not extensive, contain no species additional to those | found. The data in Table 2 were the basis of mul- tiple regression analysis using the method de- scribed by Bliss (1970). The number of gas- tropod species on an island was used as the dependent variable and the other factors — is- land area, island height, island distance from the presumed source of gastropods, stream length and water area — were the independent variables. The four first independent variables were converted to logs whereas, for conve- nience, water area was first multiplied by 100 before being converted to logs. The quantity of calcium ions (hardness) and total ions (conductivity) in the water can determine whether gastropods will be pre- sent. However, as the figures for hardness and conductivity for all streams and rivers ‚tested (Table 4) were above 4.3mgCa1 '+ 1.2 mg Mg 1 ', the amount that limits the presence of gastropods in freshwater (Aho, 1984), they were not used in the multiple re- gression analysis. RESULTS Freshwater Gastropod Survey Thirty eight species of freshwater gastro- pods were collected from the 14 islands. Twenty six were Neritidae, 10 Thiaridae, one Planorbidae and one Assimineidae (Table 3). The species found most frequently was the parthenogenetic thiarid Melanoides tubercu- GASTROPODS ON PACIFIC ISLANDS 241 lata (Table 3). It was present on 11 of the 14 islands investigated. This species is also found in East Africa, the Middle East, Asia and the Caribbean (Starmühlner, 1976). The stream-dwelling neritids, Neritina var- iegata (on 9 islands) and Septaria procellana (on 8 islands), were the next most wide- spread. These were followed by the brackish- water gastropod Neritina turrita on 7 islands. Twelve of the species were present on both North and South Pacific islands. These were Melanoides tuberculata, Neritina turrita, N. variegata, N. pulligera, N. macgillvrayi, N. squamipicta, Neritodryas subsulcata, Clithon corona, Septaria porcellana, S. lineata, S. sanguisuga and Tarebia granifera. Although in this study Thiara cancellata, Neritodryas cornea, Neritina labiosa, N. aspe- rulata and Clithon nucleolus were found only on New Georgia, the first three have been recorded from Papua New Guinea (Riech, 1937; Starmühlner, 1976) and the last two from New Caledonia (Starmühlner, 1970). The only endemic species recorded were two thiarid species, Melanoides laxa and Mel- anoides peregrina on Upolu. Water temperature, pH, hardness and con- ductivity for the islands studied and results already published from other Pacific islands are given in Table 4. Gastropods were absent from Lake Tagimaucia, Taveuni where total ions (conductivity) (14-18 us cm ') and hardness (0.8-5.0 mg Ca + Mg 1 ') were low (Southern et al., 1986) (Table 4). Hard- ness and conductivity of other freshwaters were sufficient to support gastropods (Table 4). Island Biogeography Because island area (X,) was correlated with stream length (X,) (г = 0.9377) and with water area (X.) (г = 0.8737), and water area (X,) was correlated with stream length (X,) (r = 0.9522), each made a similar contribution to the variation in the number of species (y). However, the variable water area correlated best with species numbers (r = 0.8412) (Table 2). Using the stepdown method of reducing the number of variables until only those having significant influence were left (Bliss, 1970), the best correlation obtained was with the variables water area, distance from the source of gastropods (X,) and island height (X>). These variables accounted for 93% of the variation in species numbers. When is- land height was omitted, 92% of the correla- tion was still accounted for by water area and distance. As the contribution of island height was not significant, the residuals of species numbers (у — Y) from the equation Y = 9.898 + 4.9445X, — 3.7935Х. were plotted as de- viations from the partial regression of species numbers against water area in Fig. 2. They do not depart much from linearity or from uniform scatter about the line. When distance was omitted, the correlation fell to 84%, showing that water area is the major contributor to the correlation, but distance is a significant con- tributor (p < 0.001) when taken in combina- tion with water area. However, distance by itself is not significant (r = 0.3745) for 23 is- lands. When the eight small islands with least wa- ter area (i.e. Ovalau, Rarotonga, Tongatapu, Waya, Vanuabalavu, Truk, Vava'u and Ro- tuma) were considered separately, distance from source of gastropods was the largest contributing factor to the number of species per island. When combined with water area, the two factors contributed 91% of the corre- lation, whereas distance alone contributed 81%. Species numbers were plotted against water area for the 25 islands in Figure 3. It is seen that the slope is steeper for the eight islands with small areas of water. DISCUSSION The parthenogenetic thiarid Melanoides tu- berculata, which was found on 11 of the 14 islands, can easily be spread on plant mate- rial as it gives birth to live young. One speci- men reaching an island can start a new pop- ulation, and as it inhabits ponds, ditches and taro patches as well as streams and rivers, it can survive on such islands as Tongatapu, Vava'u and Rotuma which have no running water. The buliniform planorbid Physastra nasuta, which inhabits ponds as well as running wa- ter, was present on Tongatapu, Rarotonga and Tutuila. It has been found on other Pacific islands, such as New Caledonia (Starmü- hiner, 1970), Viti Levu (Haynes, 1984) and Vanua Levu (Haynes, 1988a). Walker (1984) suggested that the genus Physastra evolved in the Australian region and spread into Southeast Asia and the Pacific through New Guinea. Physastra nasuta was collected from Tonga in 1832 (Solem, 1959), and it may HAYNES 242 X x x x X x x X x x x X x x x x X X x x x X X X X X | v 6 el € | € el 993 063 085 6E&r 559 6/1 61 59 Lv 85 Lt GE 29 811 6S¢ ¿el ewnjoH плееаепиел еАем ebag ебиоолен пелел ndejeBuo¡ етут| znı994 ejejniadse ' pinoy 2729104 ' ÂAgISMOS S//Bueo * znj99y ejordiwenbs : (euur) e1861ynd : zn¡99y 18d * (uossa7) eJebauen : (y9/eu4e7) вепэипе : (инешо) en] BuNuaN JVQILIH3N (youewe) X в/эрливаб eigale | (1019) Iunyyue ‘И/ (uossnoy\) виибэлэа y (uossnoy) exe] 'W (Pıno9) eso ‘Ww x X (spuiH) иела$е “y (sn) X X X X x EJ2/Nn918Qn} sapiouejayy X X (9IINW) 2/925$ | x бирон ejeyjaoued ‘1 (auu7) е/плеше влещц] AVGIYVIHL 31 LL 02 LL v LL selseds jo 1эашпм ELLL 9981 678 ZLL 69€ 907 (w) зчбэн tLLL 60/1 0/91 pee 6: 198 (Qu) Bay nıodn !lenes е16.оэ9 y adeuod YnıL Wen) pues} x ххх XXX XK ххх х хххх 22=2=2=2==>= хххх ххх XXX ‘sjuBiay pue seaie spue¡si ay] pue spuejsi 911984 UO juasald spodonsef JajemysaJ ay] ‘€ 319VL 243 GASTROPODS ON PACIFIC ISLANDS XXX XXX DCE CES xx xx 5915529 BUBASSOIO BAUIWISSY IVal3NINISSV (81810N) eynseu eijseskyd AVGISYONV Id (цопо) в/ецааолови 'S (91994) ebnsinbues 'S (youewe 7) Beau 'S (zn¡99y) Iualyns 'S (ouur) euejjssJod elejdas (2поэн) паэели/о ‘D (u1yOQ) /preyopud “9 (ибрпа) snsouids ‘5 (81810N) SNjoajonu ‘I (u0ssa7) sIsualuejeno ‘Od (guul7)-EU0409 'Э (Zn1994) вшарер voy ug (AqıamoS) EJP9INSANS 'N guur7 P9U109 SEÄIPOJLION (asead) EpIQN1 BION (yaaıy) ealsıuejew ESOIGE] ‘М 21984 Ивл/ибовш "N 244 HAYNES TABLE 4. The comparison of the water chemistry and the number of gastropods present in the streams of Pacific islands. Temperature Conducitivity Hardness Number of Island C pH us cm | mg Cacoı1" gastropods Savaïi 25 7.1-7.2 57.8-103.9 11.3—26.1 11 Upolu 26 6.6 78.5 20.3 15 Tutuila 27-30 6.4-7.3 146-152 15.0-33.7 13 New Georgia 25-26 6.9—7.1 181-183 21.5-22.0 20 Vava'u (L. Tu'anuku) 31 7:5 14040 407 0 (1 in pool) Tongatapu coastal pools — 7.4 1435—8061 42.9-177 3 Ponepe' — — 21-104 6-46 di Viti Levu? 23-32 5.0-7.5 42.6-231 19.5-99 31 Vanua Levu? 22-30 6.0-7.0 111.1-915 36-252 26 Ovalau? 25-26 6.7-7.0 147.1-152.3 56-60 20 Taveuni L. Tagimaacia* = 5.0-6.5 14-18 0.8-5.0(Ca + Mg) 0 streams? 21-22 5.0-5.5 36.1-66.7 9-19.7 15 Kadavu? 25-27 6.5—7.5 36.1-66.7 20-22 Ue Gau” 26-27 7.0-7.7 122—134 52—55 16 1. Maciolek & Рога (1987), 2. Haynes (1985), 3. Haynes (1988a), 4. Southern et al. (1986). TABLE 5. Freshwater gastropod habitats on Fiji Islands and the gastropods that may inhabit them Habitats 8 Ponds, dalo (taro) patches, ditches & lakes Gastropods Melanoides tuberculata, Physastra nasuta, Ferrissia noumeensis, Gyraulus montrouzieri 2. Brackish water (shaded or Neritina turrita, N. turtoni, N. auriculata, Clithon oualaniensis mangrove areas) 3. Brackish water (open areas, Neritina turrita, N. turtoni, N. auriculata, Clithon oualaniensis, C. mouths of streams & rivers) diadema, C. pritchardi, C. rarispina, C. spinosa, Septaria lineata, Assiminea crosseana, Melanoides arthurii 4. Freshwater (influenced by the C. pritchardi, C. diadema, S. lineata, Septaria porcellana, tide, lower courses of streams & Neritina squamipicta, Thiara amarula, T. bellicosa, T. scabra, T. rivers) terpsichore, Melanoides plicaria, М. arthurii, M. aspirans 5. Fast flowing streams & rivers M. tuberculata, M. lutosa, T. scabra, P. nasuta, F. noumeensis, (substrate pebbles, stones & Fluviopupa pupoidea, Fijidoma maculata, Neritina pulligera, N. boulders) petiti, N. canalis, N. porcata, N. variegata, N. macgillvrayi, Neritodryas subsulcata, Neritilia rubida, C. pritchardi, C. olivaceus, S. porcellana, S. sanguisuga, S. suffreni, S. macrocephala 6. Cascades (substrate boulders & S. porcellana, S. sanguisuga, S. suffreni, S. macrocephala rocks) have been transported to Tongatapu and Rarotonga on taro plants in recent times by man. The majority (26 species out of 38) of the snails collected were nerites (Table 3). It has been suggested that the brackish and fresh- water neritid genera, Clithon, Neritina, Neri- Ша. Neritodryas and Septaria, evolved at dif- ferent times from the marine genus Nerita probably in the Southeast Asia region (Govindan & Natarajan, 1972; Starmühlner, 1982). A few species have spread westward into the Indian Ocean, whereas many have spread eastward across the Pacific Ocean. In this survey, many more species of nerites were found in the South Pacific (25 species) than in the North Pacific (11 spe- GASTROPODS ON PACIFIC ISLANDS 245 Species numbers N It 103% 10” 10% 10' 10? Water area FIG. 2. Residual species numbers (у — Y) of fresh- water gastropods plotted as deviations from the partial regression of species numbers against water area. 30, ev. 20, = о т ow species SS 10% 10” 102 10 10 Water area (km) FIG. 3. The freshwater gastropod species num- bers-water area curve for Pacific islands. B: Bega, E: Efate, Ga: Gau, Gd: Guadalcanal, Gm: Guam, Ка: Kadavu, К: Kauai, О: Ovalau, МС: New Cale- donia, NG: New Georgia, P: Ponepe, Ra: Rarotonga, Rt: Rotuma, S: Savaïi, T: Tahiti, Tv: Taveuni, Tg: Tongatapu, Tr: Truk, Tt: Tutuila, U: Upolu, Vb: Vanuabalavu, Va: Vanua Levu, Vv: Vava'u, VL: Viti Levu, W: Waya. cies). All species found in the North Pacific were also present in the South Pacific (Table 3). It appears that more species have moved south through the New Guinea-Solomon Is- land region than have moved north into Mi- cronesia. Such species as Clithon nucleolus, Neritina asperulata and N. labiosa malanisica do not appear to have dispersed further east than Solomon Islands and New Caledonia, whereas Clithon pritchardi, Septaria macro- cephala and S. suffreni probably arose in the South Pacific as they are not found as far north as Vanuatu and Solomon Islands (Fig. ie Unlike land snails, which show consider- able speciation on Pacific Islands, e.g. Partula on Samoa and zonitids in Fiji (Solem, 1959), comparatively few species of endemic freshwater gastropods have been found. Be- sides the two endemic species of Thiaridae, Melanoides laxa and M. peregrina collected from Upolu, other endemic species recorded on islands discussed in this paper are Fiji- doma maculata (Thiaridae), Fluviopupa pupoidea (Hydrobiidae) (Viti Levu); ап opisthobranch, Acochlidium sp. (Vanua Levu); Melanopsis frustulum, М. mariei (Thiaridae), Fluviopupa minor and two other Fluviopupa spp., Hemistomia caledonica (Hy- drobiidae), Physastra petiti (Planorbidae) (New Caledonia); Fluviopupa brevior (Efate) and the eight endemic species on Kauai men- tioned above (Morrison, 1954; Starmühlner, 1970, 1976; Haynes, 1988b; Burch & Patter- son, 1971; Maciolek, 1978). Although man has probably helped in the distribution of Melanoides tuberculata and Physastra nasuta, which live in taro patches, it is unlikely that man has been responsible for the spread of other species to Pacific is- lands. Most freshwater gastropods do not live on vegetation but are found on the mud or rocks of stream or river bottoms. They are not favored as food and therefore the chance of them being spread purposely by man is small. Some brackish-water neritid species may cling to wooden boats and be carried to nearby islands. Other neritid and thiarid spe- cies may be rafted out to sea on tree trunks during flooding and be washed ashore at a river or stream mouth. However, many spe- cies are probably distributed from island to island as veliger larvae. Most neritid and brackish-water thiarid gastropods hatch as veligers. These may be swept out to sea and settle in brackish water at the mouth of a stream on another island. Ford (1979) re- ported long lines of young Neritina granosa migrating upstream on Hawaiian Islands. He believed that the veligers, after being swept down to the sea, spent some weeks in salt water before settling at the mouth of a stream and starting their migration upstream. There is no evidence to suggest that this occurs in 246 HAYNES all neritid species, but Neritina, Clithon and Septaria veligers kept in the laboratory can be acclimatized to sea water, and they have re- mained alive for 22 days without settling. This allows them time to be carried by currents to quite distant islands. However, they are more likely to reach and become established on is- lands that are near the source of the gastro- pod veligers. Island Biogeography Ассогата to the equilibrium theory of is- land biogeography (MacArthur & Wilson, 1967), the greater the distance of an island from a source of colinization, the smaller the probability of colonization. However, if islands are the same distance from the source, immi- gration will be greater to the larger island. Iso- lated small populations on small islands will have a higher rate of extinction due to com- petition and population fluctuations. If further immigration occurs after all potential niches are filled, interspecific interactions will in- crease, and the extinction rate will increase and keep the species number in equilibrium. On the 25 Pacific islands considered, the total area of water was the main factor influ- encing the number of freshwater gastropod species present (explaining 84% of the vari- ation). Because island area and stream length are strongly correlated with water area, their influence on the number of species is incorporated in water area. Distance from the source contributes 8% to the variation in the number of species and unknown factors 7%. The contribution of height is also largely in- corporated in water area (r = 0.7312) be- cause an island with an altitude less than 300 m usually will be without streams, and in gen- eral the higher an island the greater its stream length, water area and habitat diversity. The importance that distance contributes to species variation on small islands may be due to the strong possibility of the small area of water drying up and the consequent likelihood of extinction of some or all gastropods. The nearer such islands are to a source of gastro- pods the more likely immigration is to occur and the number of species to be restored. Ovalau (20 species) and Веда (13 species), which are close to Viti Levu, have a relatively large number of species, whereas the more distant islands, such as Rarotonga (3 spe- cies), Truk (4 species) and Vanuabalavu (4 species), have few species (Tables 2, 3). Freshwaters on Pacific islands can be di- vided into six distinct habitats: (1) ponds, taro patches, ditches; (2) shaded brackish water; (3) open brackish water; (4) freshwater influ- enced by the tide; (5) fast flowing streams and rivers; and (6) cascades (Table 5). Some are inhabited by only a few gastropods, and others are suitable for colonization by a large number of gastropod species. Small islands and islands of low elevation do not have all these different habitats, but those they do have fall into one of these categories. The species inhabiting the habitats are not all the same for each island group. The number of gastropod species on an is- land will partially depend on the number of each kind of habitat and their size. These are factors which account for some or all of the unknown 7% in variation of the number of gastropod species on islands. The steeper slope for islands with a small area of water has been observed in species- area curves before (Fig. 3). Williams (1981) gives a similar plot for birds on the Solomon Islands, and Lassen (1975) drew another for freshwater snails in small eutrophic lakes in Denmark. This steeper slope for smaller ponds Lassen (1975) explained by lower im- migration and an increased extinction rate with decreasing area. Birds carrying immi- grant snails are less likely to visit small ponds, and small ponds are more likely to freeze. Similarly, a steeper slope was obtained for Pacific islands with small water area, because the extinction rate increases due to ponds and lower courses drying up and because the survival rate of immigrants is low due to rela- tively few available habitats. Most investigations into which factors de- termine the number of species on islands have involved plants or birds. Johnson & ‘ Raven (1970) found that island area, latitude and soil types were important in the species diversity of plants on the British Isles and on California islands. Harris (1973), using multi- variate analysis, established that the vari- ables that contributed to the variation of num- bers of breeding land birds on the Galapagos Islands were total plants and altitude (87.7%) and distance (90.5%). Power (1972) found by multivariate analysis that the variation in the numbers of bird species on California islands was caused by the interaction of these vari- ables: numbers of native plant species and distance from other islands and from the mainland. The variation in numbers of plant species was mainly explained by island area and latitude. GASTROPODS ON PACIFIC ISLANDS 247 In this investigation, island area and height were important because they determine the diversity and size of the freshwater habitats available. The habitat diversity is best ex- pressed as water area for purposes of multi- ple regression analysis. Distance from a pos- sible source of new immigrants is also important in determining species numbers, probably because of the high rate of extinc- tion caused by water drying up and some- times by whole populations being washed away during tropical cyclones. ACKNOWLEDGEMENTS | wish to thank the University of the South Pacific for providing a research grant for this work and Dr. J. Maciolek and Mr. J. Ford for making available their collections of freshwa- ter gastropods from Ponepe. LITERATURE CITED AHO, A., 1984, Relative importance of hydrochem- ical and equilibrial variables on the diversity of freshwater gastropods in Finland. Pp. 198-206, in SOLEM, A. & A.C. VAN BRUGGEN, eds. World-wide snails: Biogeographical studies on non-marine Mollusca. Brill/Backhuys, Leiden. BLISS, С. 1., 1970, Statistics in Biology, Vol. 2. Mc- Graw-Hill, New York. 639 pp. BURCH, J. B. & C. H. PATTERSON, 1971, Chro- mosome number of Hawaiian Lymnaeidae. Mal- acological Review, 4(2): 209-210. CARLQUIST, S., 1974, Island biology. Columbia University Press. New York. 266 pp. DIAMOND, J., 1984, Biogeographic mosiac in the Pacific. Biogeography of the Tropical Pacific: Proceedings of a Symposium. Bishop Museum Special Publication, 72: 1-14. FORD, J. 1., 1979, Biology of a Hawaiian fluvial gastropod Neritina granosa Sowerby (Proso- branchia: Neritidae). M.S. Thesis, University of Hawaii. GOVINDAN, K. & R. NATARAJAN 1972, Studies on Neritidae (Neritacea: Prosobranchia) from peninsular India. Indian National Science Acad- emy Proceedings, Part B 225-239. HARRIS, M. P., 1973, The Galapagos avifauna. Condor, 75: 265-278. HAYNES, A., 1984, Guide to the brackish and fresh water gastropods of Fiji. Institute of Natural Re- sources, University of the South Pacific. 37 pp. HAYNES, A., 1985, The ecology and local distribu- tion of non-marine aquatic gastropods in Viti Levu, Fiji. The Veliger, 28(2): 204-210. HAYNES, A., 1988a, The gastropods in the Streams and rivers of five Fiji islands (Vanua Levu, Ovalau, Gau, Kadavu and Taveuni). The Veliger 30(4): 377-383. HAYNES, A., 1988b, A population of the Fijian freshwater thiarid gastropod Fijidoma maculata (Mousson). Archiv für Hydrobiologie, 113(1): 27- 39. JOHNSON, М. Р. & Р.Н. RAVEN, 1970, Natural regulation of plant species diversity. Evolutionary Biology, 4: 127-162. LASSEN, H. H., 1975, The diversity of freshwater snails in view of the equilibrium theory of island biogeography. Oecology, (Berl) 19:1-8. MACARTHUR, В. Н. & Е. О. WILSON, 1967, The theory of island biogeography. Princeton Univer- sity Press, New Jersey 203 pp. Monographs in Population Biology 1. MACIOLEK, J. A., 1978, Shell character and habi- tat of nonmarine Hawaiian neritid snails. Micron- esica, 14 (2): 209-214. MACIOLEK, J. А. & J. 1. FORD, 1987, Macrofauna and environment of the Nanpil-Kiepw river, Ponepe, Eastern Caroline Islands. Bulletin of Marine Science, 4(12): 623-632. MORRISON, J. P. E., 1954, The relationships of old and new world melanians. Proceedings of the United States National Museum, 103(3325): 357-394. POWER, D. M., 1972, Numbers of bird species on the California Islands. Evolution, 26: 451-463. RIECH, E., 1937, Systematische, anatomische, ökologische und tiergeographische Unterschun- gen über die Susswassermollusken Papuasiens und Melanesiens. Archiv für Naturgeschichte (N.F.) 6(36): 40-101. SOLEM, A., 1959, Systematics and zoogeography of the land and freshwater Mollusca of the New Hebrides, Fieldiana: Zoology, 43: 1-359. SOUTHERN, W., J. ASH, J. BRODIE & P. RYAN, 1986, The flora, fauna and water chemistry of Tagimaucia crater, a tropical highland lake and swamp in Fiji. Freshwater Biology, 16: 509— 520. STARMUHLNER, F., 1970, Etudes hydrobi- ologiques en Nouvelle-Caledonie. O.R.S.T.O.M., Sér Hydrobiologie, 4(3/4): 3-127. STARMUHLNER, F., 1976, Beitrage zur Kenntnis der Süsswasser-Gastropoden pazifischer Inseln. Annalen des Naturhistorischen Museum in Wien, 80: 473—656. STARMUHLNER, F., 1982, Occurence, distribution and geographical range of the freshwater gastro- pods of the Andaman Islands. Malacologia, 22 (1/2): 455-656. STARMUHLNER, F., 1986, The fresh- and brack- ishwater gastropods of the Tongan and Samoan Islands. 9th International Malacological Con- gress, Edinburgh 12 pp. THORNE, R. F., 1963, Biotic distribution patterns in the tropical Pacific. Pp. 311-350 in GRESSITT, J. L., ed., Pacific basin biogeography. Bishop Museum Press, Honolulu. 248 HAYNES WALKER, J. C., 1984, Geographical relationships WILLIAMS, M., 1981, Island populations. Oxford of the buliniform planorbids of Australia. Pp. University Press, Oxford. 286 pp. 189-197 in SOLEM, A. & A. C. VAN BRUGGEN, World-wide Snails: Biogeographical studies on non-marine Mollusca. Brill/Backhuys, Leiden. Revised Ms. accepted 18 August 1989 MALACOLOGIA, 1990, 31(2): 249-257 ANALYSIS OF LYMNAEACEAN RELATIONSHIPS USING PHYLOGENETIC SYSTEMATICS Donald L. Swiderski Department of Geological Sciences, Michigan State University, East Lansing, Michigan, U.S.A. 48824 ABSTRACT Currently, evolutionary studies of lymnaeacean pulmonates are heavily dependent оп a small number of classical morphological studies for family-level phylogenetic relationships. These classical studies are in general agreement on the relationships of the Iymnaeacean families. Unfortunately, all of the previous studies infer relationships from a priori arguments for character evolution based on assumptions of the evolutionary or adaptive significance of the characters in question. Considering the widespread convergence in pulmonates, the assumptions may not be justified and the phylogenetic inferences derived from them are probably suspect. The present study employs outgroup analysis and component analysis to test the phyloge- netic implications of previously published character-state distributions. The purpose of this study is to determine whether the morphological descriptions reported in the literature support either the currently accepted phylogeny, or an alternative interpretation. The results of the outgroup analysis indicate that only a few of the characters described in the literature permit lym- naeaceans to be discriminated from all related pulmonates. The resuiis of the component analysis indicate that the few informative characters provide weak support for accepting a revised lymnaeacean phylogeny, but strongly support rejection of the classical interpretation. Key words: Lymnaeacea, phylogeny, component analysis, outgroup analysis. INTRODUCTION The pulmonate superfamily Lymnaeacea includes six families of freshwater snails: Chil- inidae, Latiidae, Acroloxidae, Physidae, Lym- naeidae and Planorbidae (Hubendick, 1978). (Although ICZN Recommendation 29A sug- gests superfamily names end in -oidea, -acea is conventional for this group and is the end- ing used in this paper.) The lymnaeaceans have a nearly global distribution (Hubendick, 1978) and occupy a wide variety of freshwater habitats (cf. Clarke, 1973). Associated with their large ecological range is tremendous morphological diversity, resulting in several hundred named species (cf., Clarke, 1973). This high level of diversity makes phyloge- netic studies of the Lymnaeacea difficult. Despite the difficulty of resolving relation- ships within the superfamily, interest in the problem persists. One motivation results from their ecological diversity; the Lymnaeacea are useful as indicators of ecological conditions, both in Recent (Aho, 1966; Clarke, 1979) and fossil (Ayyasamy et al., 1985; Good, 1987; La Rocque, 1966-1970) habitats. Phylogenetic studies may be useful in identifying traits or 249 taxonomic groups associated with particular environments. Another motivation results from the role of many species as intermediate hosts for trematode parasites (Gomez et al., 1986; Mandahl-Barth, 1957). Here, phyloge- netic studies may be relevant to analyses of host-parasite co-evolution. Interest in lymnaeacean phylogeny tends to focus on lower taxonomic levels: genera or species (e.g. Jelnes, 1986, Bulinus; Meier- Brook, 1983, Gyraulus). Studies at lower lev- els necessarily take the family-level phylog- eny as given. The few previous family-level analyses (Hubendick, 1947, 1978; Star- obogatov, 1967) support the phylogeny shown in Figure 1. The concordance of these studies would normally be taken as a sign of reliability and robustness, but these studies are based on similar material and share a common approach. The authors argue that the gonad (Hubendick, 1978; Starobogatov, 1967), prostate (Hubendick, 1947, 1978; Starobogatov, 1967) and male copulatory or- gans (Starobogatov, 1967) are more impor- tant than any other traits for phylogeny recon- struction because reproductive-tract char- acters are crucial to reproductive Success. 250 SWIDERSKI Chilinidae Latiidae Acroloxidae Lymnaeidae Physidae Ancyloplanorbidae FIG. 1. Phylogenetic relationships supported by previously published analyses. Therefore, a sequence of improvements in these structures should reflect phylogenetic history. However, reproductive success de- pends on many factors in addition to gamete production and mating ability. Survival and the opportunity to mate depend, in part, on respiratory and digestive abilities. Therefore, respiratory and digestive structures are also crucial to reproductive success, and should not be given less weight than reproductive structures in phylogenetic inference. Harry (1964) uses Dollo parsimony to infer directions of character transformations from a phylogeny similar to Figure 1. Dollo parsi- mony assumes that acquisition of a new char- acter state is rare, but that loss of a derived state, reverting to a more primitive state, is much more frequent. Harry’s results indicate that reproductive traits, as well as digestive and respiratory traits, are convergent. In ad- dition, Harry’s results indicate that support for Figure 1 rests largely on shared primitive traits. The criticisms of previous work should not be construed to mean that morphological traits used in previous studies of the Lymnae- acea provide no basis for phylogenetic infer- ence. These criticisms are only intended to point out that inferred patterns of morpholog- ical change of all characters should be tested as hypotheses. Component analysis (Nelson & Platnick, 1981) is a cladistic approach to phylogeny reconstruction designed to test hy- potheses of character evolution. Since a phy- logenetic branching pattern can be repre- sented as a series of nested sets of taxa, component analysis tests whether the sets of taxa implied by hypotheses of character evo- lution do nest. A character may have two states implying a transformation from a pre- existing, primitive state to a new, derived state. The state hypothesized to be derived is expected to define a monophyletic group composed of all descendants of the species in which the character state transformation occurred. A component is the set of taxa that share the state hypothesized to be derived; it represents a hypothesis of monophyly. If two components nest, then both hypotheses of monophyly are consistent with the same phy- logenetic pattern, and corroborate both hy- potheses of character evolution (Le Quesne, 1969; Nelson & Platnick, 1981). In a special case, two derived states define identical, rep- licated components, providing the strongest possible corroboration of the two character transformation hypotheses (Nelson & Plat- nick, 1981). There are two cases in which components do not nest. In one case, the components are intersecting sets represent- ing conflicting hypotheses of monophyly, and at least one of the character hypotheses must be rejected (Le Quesne, 1969). In the other case, the components are mutually exclusive, and the character hypotheses they represent need not be rejected (Le Quesne, 1969), but they are not corroborated either (Nelson & Platnick, 1981). The treatment of mutually ex- clusive components distinguishes clique or compatibility analysis from component analy- sis. In clique analysis, a clique is a set of com- ponents that do not conflict, and the largest clique is chosen as the best estimate of the phylogeny (Estabrook et al., 1977). In com- ponent analysis, only nested and replicated components are used, and the largest set of nested components, representing the largest set of mutually corroborated character hy- potheses, is chosen as the best estimate of the phylogeny (Nelson & Platnick, 1981). Component analysis, and all other cladistic methods, are critically dependent on the ‚ sources used to generate hypotheses of char- acter transformation. Several sources have been used; three common ones are outgroup analysis, ontogenetic analysis and paleonto- logical (stratigraphic) analysis (cf. Eldredge & Cracraft, 1980; Nelson & Platnick, 1981). For this study, | chose to use outgroup analysis because it is an extension of component anal- ysis (Eldredge & Cracraft, 1980; Wiley, 1981). Outgroup analysis assumes that the study group (ingroup) is monophyletic and treats the ingroup as a component. Related taxa (outgroups) are members of larger compo- nents that include the ingroup. Outgroup anal- ysis sorts character states into two sets: (1) those shared by both ingroup and outgroups, and (2) those restricted to the ingroup. Char- PHYLOGENETIC SYSTEMATICS OF LYMNAEACEA 251 acter states shared by the ingroup and any outgroup may be either primitive or conver- gent (Maddison et al., 1984; Wiley, 1981). In either case, these character states cannot be used for phylogeny reconstruction. Only de- rived states define components that are sub- sets of the ingroup; this is the essence of cla- distic methodology (Estabrook et al., 1977; Eldredge & Cracraft, 1980; Nelson & Platnick, 1981; Wiley, 1981). Outgroup analysis is a method that eliminates character transforma- tion hypotheses inconsistent with the hypoth- esis of ingroup monophyly. When the consis- tent character hypotheses are used in component analysis, the resulting phylogeny would be based on the largest set of mutually corroborated character hypotheses consis- tent with the initial hypothesis of ingroup monophyly. The results could be refined iter- atively by using the ingroup taxa found to be primitive as functional outgroups to order the states of characters not found in the original outgroups (Eldredge & Cracraft, 1980; Wa- trous & Wheeler, 1981). The study presented here is a re-evaluation ofthe phylogenetic relationships of the six Iym- naeacean families, using outgroup analysis and component analysis. Parsimony algo- rithms were not used because previous stud- ies of the Iymnaeaceans indicated consider- ably homoplasy; under these circumstances, parsimony algorithms become unreliable (Felsenstein, 1978). Because the purpose of this study is to test the phylogenetic conclu- sions of earlier studies, | have used published morphological descriptions. The principal sources of morphological descriptions of lym- naeaceans are the four previous studies of lymnaeacean phylogeny (Harry, 1964; Huben- dick, 1947, 1978; Starobogatov, 1967). Addi- tional studies of more limited taxonomic or morphological scope were examined if their data were prominently featured in the phylo- genetic studies cited above (e.g. Demian, 1962, radula; Duncan, 1960a, 1069b, oviduct; Hubendick, 1964, ancylids). The superfamilies Amphibolacea and Ellobiacea were used as the outgroups, with descriptions provided pri- marily by Hubendick (1978). | have provisionally accepted the family and superfamily taxonomy of Hubendick (1978), in which Lymnaeacea Rafinesque (1815) is equivalent to Hygrophila Ferussac (1821). Hubendick’s (1978) six major subdivisions of the Lymnaeacea do not differ from the subdi- visions of Hygrophila recognized by Harry (1964) or Starobogatov (1967). The differ- ences among these three authors are prima- rily nomenclatural. Brief descriptions of the contents of the six lymnaeacean families are given in the Appendix. OUTGROUP ANALYSIS Outgroup analysis was performed by com- paring the descriptions of the lymnaeaceans to the descriptions of the outgroups. Because of the large amount of convergence in the order Basommatophora, which includes the Lym- naeacea, the nearest relatives of the lym- naeaceans cannot be identified confidently (Duncan, 1960a; Hubendick, 1978; Tillier, 1984). While the inability to identify the nearest relative may be a problem for parsimony al- gorithms (Maddison et al., 1984), it need not be a problem for components analysis (El- dredge & Cracraft, 1980). The purpose of out- group analysis is to identify the derived states of the ingroup. The nearest outgroup is likely to provide the best estimate (Wiley, 1981), but any outgroup will provide a partial estimate (Eldredge & Cracraft, 1980), and no single outgroup is likely to provide a completely ac- curate estimate (Maddison et al., 1984). Therefore, any non-lymnaeacean basom- matophoran could be used as an outgroup. The outgroups used in this study were the Ellobiacea and Amphibolacea, which encom- pass most of the non-lymnaeacean basom- matophorans. Any trait shared by lymnae- aceans with either of these other superfamilies was considered either primitive or convergent and rejected from the phylogenetic analysis. Only those traits unique to the Lymnaeacea were considered derived character states and subjected to further study. As shown in Table 1, only five characters have derived states that are both unique to the Lymnaeacea and shared by at least two lymnaeacean families. These are the only character states that might reflect phyloge- netic relationships (Nelson & Platnick, 1981). Each of the five characters in Table 1 are dis- cussed below. For each character, the vari- ous states are briefly described, and the de- rived state is identified. 1—Prostate morphology. The prostates of the outgroups Ellobiacea and Amphibolacea are comprised of a smooth glandular epithe- lium along the male duct or groove. This type of prostate is present in most chilinids. Three, more complex morphologies are found in the lymnaeaceans: (1a) a patch of alveoli in some 252 SWIDERSKI TABLE 1. Character-state distributions across Iymnaeacean families. Only characters with derived states shared by at least two families are listed. Derived states are italicized. Prostate Stomach morphology muscles Outgroups smooth/pocket cylinder/diverticula Chilinidae smooth/alveoli bilobed Latiidae smooth cylinder Acroloxidae smooth absent Lymnaeidae folds bilobed Physidae diverticula reduced Planorbidae diverticula cylinder/bilobed chilinids, (1b) series of elongate digitiform di- verticula in Physidae and Planorbidae, (1c) a dilation of the vas deferens with invaginated folds in Iymnaeids. The invaginated folds are unique to the Lymnaeidae and do not require further discussion in this paper. The compar- ison between alveoli and diverticula does merit further discussion. Starobogatov (1967) argues that all of the more complex morphol- ogies arise in response to a need for more efficient packing of prostate tissue and that these morphologies increase secretory sur- face area relative to the total volume occupied by the prostate. He also argues that evagina- tion and invagination are fundamentally dis- tinct approaches to the packing problem. Fol- lowing Starobogatov’s argument, alveoli and diverticula are homologs, both are evagina- tions and the component defined by evagina- tion includes Physidae, Planorbidae and some chilinids. Alternatively, alveoli and di- verticula are regarded as completely separate traits, so that diverticula define a component that includes only Physidae and Planorbidae. Because available literature does not provide sufficient information to resolve this issue, two components are listed in Table 2: 1’, defined by evagination (some Chilinidae, Physidae and Planorbidae); and 1'”, defined by diver- ticula (Physidae and Planorbidae). Because there is no definitive evidence that diverticula are derived from alveoli, component 1’’ can- not be considered a subset of 1’. Instead, 1’ and 1’’ are considered alternative interpreta- tions of a single character, and their relation- ships to other components were examined in- dependently. 2—Stomach muscle arrangement. Ellobia- cea and Amphibolacea have well-developed stomach muscles in one of two arrangements: a cylindrical band around the stomach, or a muscular diverticulum. The muscular divertic- Ciliated Pneumostomal pulmonary Radular lappet ridge row single present horizontal single present chevron single present chevron single present chevron siphon absent horizontal siphon absent chevron single/siphon/other present/absent horizontal ulum is found only in the outgroups; but the cylindrical band is found in some lym- naeaceans. Two new states are found in Iym- naeaceans: (2a) reduction and loss of stom- ach muscle, and (2b), organization of muscles into two lobes. Reduction and loss are shared by Acroloxidae and Physidae. The bilobed ar- rangement is shared by Chilinidae, Lymnaei- dae and most Planorbidae. Because not all planorbids are included in component 2b, the family name is enclosed in brackets in Table 2. 3—Pneumostomal lappet. The pneumo- stomal lappet is a fold external to the pulmo- nary opening. In both outgroups, the lappet is a single lobe bisected by the rectum and may function as a gill. In Lymnaeidae, Physidae and most Planorbidae, the region anterior to the rectum is converted to a siphon, a tube which appears to function as a snorkel (Harry, 1964). In Lymnaeidae and Physidae, the re- gion posterior to the rectum is absent. The posterior region is often reduced, but rarely absent, in planorbids with a siphon (Huben- dick, 1955). Other variations of the pneumo- stomal lappet occur in those planorbids with- ‘ out a siphon (Hubendick, 1964). 4—Ciliated pulmonary ridge. This is an in- ternal structure of the pulmonate lung that ex- tends from the pulmonary opening to the apex of the lung on both dorsal and ventral sur- faces. The ridge appears to facilitate gas ex- change by regulating water flow through the lung (Pilkington et al., 1984; Sullivan & Cheng, 1974). The ridge is present in both outgroups and many Iymnaeaceans, but is absent from Lymnaeidae, Physidae and sev- eral planorbids. 5—Radular tooth arrangement. The geo- metric arrangement of teeth in rows appears to be the only radular trait that is not highly variable and frequently convergent (Demian, 1962; Hubendick, 1978). Straight transverse PHYLOGENETIC SYSTEMATICS OF LYMNAEACEA 253 TABLE 2. Components defined by shared derived character states. Brackets indicate families in which not all species possess the derived state. de [Chilinidae], Physidae, Planorbidae ile Physidae, Planorbidae 2a Acroloxidae, Physidae 2b Chilinidae, Lymnaeidae, [Planorbidae] 3 Lymnaeidae, Physidae, [Planorbidae] 4 Lymnaeidae, Physidae, [Planorbidae] 5 Chilinidae, Latiidae, Acroloxidae, Physidae tooth rows are present in all outgroups and some lymnaeaceans. Chevron-shaped rows distinguish four lymnaeacean families: Chilin- idae, Latiidae, Acroloxidae and Physidae. COMPONENT ANALYSIS All characters states unique to Lymnaeacea are hypothesized to be derived. Each charac- ter state defines a set of taxa that is hypoth- esized to represent a monophyletic group. Two states listed in Table 1 (folds in the lym- naeid prostate, alveoli in the chilinid prostate) define components that include only the mem- bers of individual families. Because these traits are not shared by two or more families, they cannot support inferences of relation- ships between families (Nelson & Platnick, 1981). These states are included in Table 1 for completeness in the lists of character-state distributions but are excluded from the com- ponent analysis. Other derived states unique to single families (e.g. preputial gland of Phys- idae; Te, 1975) were omitted from Table 1 and are not considered further. For each remaining derived state listed in Table 1, the component, the set of taxa sharing that state, is listed in Table 2. Component analysis is performed by in- specting all possible pairs of components to determine whether there are pairs of nested sets. Nested pairs are consistent with a single phylogenetic branching pattern and therefore represent mutually corroborated hypotheses of monophyly. Next, all possible combinations of nested pairs are assembled. The largest combination, the largest number of mutually corroborated hypotheses of monophyly, is considered the best estimate of the actual phylogeny. In a few cases, not all members of a family possess a particular derived state. Such com- ponents conflict with the hypothesis that the given family is a monophyletic group. Nor- mally, the monophyly of a family would not be challenged by a study of family-level relation- ships, and the traits that conflict with the fam- ily definition would be rejected as homoplas- tic. However, several cases involve one family, the Planorbidae. Therefore, | exam- ined the distribution of this set of traits across genera to determine whether they consis- tently divide the planorbids into two or more smaller groups. Two traits co-occur in most planorbids: loss of the ciliated pulmonary ridge (character 3), and formation of a siphon (character 4). How- ever, there are snails with a siphon that have not lost the ciliated ridge, and snails that have lost the ciliated ridge without acquiring a si- phon (Hubendick, 1955, 1964, 1978). Thus, the presence of the siphon and the loss of the ridge do not coincide in all planorbids and do not support an argument for dividing the fam- ily. Furthermore, since these two traits have conflicting distributions, one or both must be homoplastic. Hubendick (1955) shows differ- ent patterns of partial ridge loss in the coiled planorbids: some losing the dorsal portion of the ridge, others losing the ventral portion of the ridge. This diversity in intermediate states may mean that the terminal state, complete ridge loss, can be reached by at least two different evolutionary routes. This is not proof that ridge loss is convergent, but it does sup- port the argument of Hecht & Edwards (1976) that losses are more likely than new additions to be convergent. The third trait dividing the Planorbidae is the organization of stomach muscles into two lobes (character state 2b). The published data on this trait are sparse but indicate that only the planorbid limpets lack the derived state (Hubendick, 1964, 1978). Thus, the trait represents a third way of dividing the Planor- bidae. Only one, if any, can be right. The cor- rect trait can be recognized only if it defines a component that nests with one of the compo- nents that include all of the Planorbidae. Because the brackets do not represent identical or nested sets of genera, none of the components in Table 2 are identical: no two derived states independently support the same phylogenetic inference. Components 3 and 4 appear similar; both include Lymnaei- dae, Physidae and some planorbids; but they divide the Planorbidae into different groups, representing conflicting hypotheses of rela- tionship. In fact, most pairs of components represent conflicting hypotheses of relation- ships. One exception is composed of compo- 254 Ancyloplanorbidae Lymnaeidae Chilinidae Latiidae Acroloxidae Physidae FIG. 2. Phylogenetic relationships supported by component analysis. nents 2a (Acroloxidae and Physidae) and 2b (Chilinidae, Lymnaeidae and Planorbidae). These two components are mutually exclu- sive, representing two independent hypothe- ses of character evolution in separate lin- eages. The components are not contradictory and could be used in clique analysis, but they do not corroborate each other. Consequently, the relationship between 2a and 2b does not contribute to the component analysis solution. The only nested components, representing mutually corroborated character transforma- tion hypotheses, are 2a (Acroloxidae and Physidae) and 5 (Chilinidae, Latiidae, Ac- roloxidae and Physidae). Therefore, the only phylogenetic relationships supported by com- ponent analysis are those shown in Figure 2. The branching pattern in Figure 2 is not completely resolved: there are two trichoto- mies. Each trichotomy indicates that the rela- tionship of three lineages remains unre- solved. Each trichotomy has three possible solutions (Eldredge & Cracraft, 1980; Nelson & Platnick, 1981), so there are nine fully re- solved trees consistent with Figure 2. How- ever, Figure 2 does indicate that within Lym- naeacea there is а monophyletic group characterized by a unique, derived, chevron radular row (component 5). This group in- cludes four families: Chilinidae, Latiidae, Ac- roloxidae and Physidae. The relationships of Lymnaeidae and Planorbidae to each other and to the group remain unresolved. Within the group defined by component 5, the rela- tionships of Chilinidae and Latiidae are un- clear, but Physidae and Acroloxidae (compo- nent 2a) appear to represent a distinct lineage characterized by reduced stomach muscles. DISCUSSION The relationships shown in Figure 2 are based on only two derived character states. SWIDERSKI With so little support, this phylogeny could be rejected rather easily. Only one additional de- rived state defining a component that nests with any of the other components in Table 2 would produce an equally well-supported al- ternative phylogeny. Because phylogenies based on few traits are highly susceptible to revision, Figure 2 can only be regarded as a tentative hypothesis of lymnaeacean relation- ships. Although outgroup analysis of the charac- ters available in the lymnaeacean literature did not produce a strongly supported new phylog- eny, the results indicate that the generally ac- cepted phylogeny (Figure 1) should be re- jected. Only one component of Figure 1 was confirmed by outgroup analysis: Physidae + Planorbidae, defined by the prostate divertic- ula. None of the other monophyletic groups implied by Figure 1 is listed as a component in Table 2. Furthermore, half of the components in Table 2 conflict with the basal dichotomy shown in the conventional phylogeny. Com- ponents 3 and 4, defined by respiratory traits, are close to matching one branch of Figure 1, but they conflict over which planorbids belong to that lineage. Thus, the outgroup analysis provides an argument for rejecting the con- ventional lymnaeacean phylogeny, indepen- dent of the support it provides for a specific revision. These results also cast doubt on the use of most reproductive tract characters for phylog- eny reconstruction. This is significant be- cause reproductive traits have been the prin- cipal characters considered in previous phylogenetic studies of the Lymnaeacea (separation of male and female ducts, Harry, 1964, Hubendick, 1947, 1978; prostate, Hubendick, 1947, 1978, Starobogatov, 1967; preputium, Harry, 1964, Hubendick, 1947). Based on outgroup analysis, most evolution- ary changes in the lymnaeacean reproductive system are not unique to that superfamily. Only one reproductive character, prostate morphology, has a unique derived state listed in Table 1. Considering the number of sepa- rate, identifiable reproductive structures, the lack of unique derived states implies tremen- dous homoplasy. This large amount of ho- moplasy is not a surprise, however; because phylogenetic studies within lymnaeacean families frequently conflict when different re- productive traits are used (Hubendick, 1951, 1955; Meier-Brook, 1983; Te, 1975, 1978). In addition, the patterns of character evolution described for reproductive traits conflict with PHYLOGENETIC SYSTEMATICS OF LYMNAEACEA 255 the few patterns that have been described for respiratory and radular characters (Huben- dick, 1955, 1978; Meier-Brook, 1983; Te, 1978). Evidently, evolutionary changes of the reproductive system do not unambiguously reflect lymnaeacean relationships. While the results of the current study reject the use of reproductive characters for phylog- eny reconstruction, this study does not reject the possible evolutionary significance of these traits. In fact, evolutionary significance may account for the lack of phylogenetic sig- nificance. A partial explanation of conver- gence is that the functional or adaptive impor- tance of a trait ensures strong selective pressures favoring any changes that might improve function. This can be only a partial explanation of frequent convergence because the genetic and developmental sources of the necessary variation are not considered. Still, lymnaeacean reproductive characters may be examples of traits with great functional impor- tance that are not unique innovations, but the results of frequent convergence. Evolutionary significance and the causes of convergence are outside the scope of this pa- per. The focus of this study is that outgroup analysis of published data demonstrates that confidence in any interpretation of lymnaea- cean relationships is misplaced. Failure to produce a well-corroborated phylogeny of the Lymnaeacea is due, in part, to the uncertainty concerning the outgroup phylogeny. If out- group relationships were understood, it might be possible to determine which outgroup traits are most likely to be primitive and which traits are probably convergent (Maddison et al., 1984). Discriminating between primitive and convergent traits would help focus efforts aimed at identifying and discriminating among separate convergence events. Ultimately, recognition of the unique aspects of individual convergence events may enable the identifi- cation of separate monophyletic groups among convergent taxa (e.g. Lombard & Wake, 1986). Resolving outgroups and reproductive con- vergence provides only a partial solution to the problem of lymnaeacean phylogeny. The results of this study show that the lymnaea- cean phylogeny cannot be fully resolved us- ing currently available, morphological data. New data should be generated both from de- scriptions of morphological traits in other or- gan systems and from analysis of molecular traits. Granted, new data may be as prone to convergence as the traits discussed in this report, but there is no possibility of a solution until these other avenues are explored. ACKNOWLEDGMENTS This paper is based on analyses performed as part of a M.S. thesis for the Department of Geological Sciences, Michigan State Univer- sity. | would like to thank my advisory com- mittee: R. L. Anstey, D. F. Sibley and D. O. Straney. | would also like to thank D. O. Straney, М. L. Zelditch, A. С. Carmichael, and the reviewers for their comments on earlier versions of this paper. LITERATURE CITED AGEITOS DE CASTELLANO, Z. J. & S. E. MIQUEL, 1980, Notas complementarias al gen- ero Chilina Gray (Mollusca Pulmonata). Neotro- pica, 26: 171-178. AHO, J., 1966, Ecologica! basis of the distribution of the freshwater molluscs in the vicinity of Tam- pere, South Finland. Annales Zoologici Fennici, 3: 287-322. AYYASAMY, К., V. GANESAN & С. V. L. 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These families share the following traits: a glandular oviduct divided into histologically and functionally distinct regions (Duncan, 1960a, 1960b), freshwater habitat, and loss of the operculum in both adult and embryo (Hubendick, 1978). None of these traits are unique to lymnaeaceans, but together these traits serve to distinguish the Lymnaeacea from other basommatophorans. Conse- quently, the Lymnaeacea is generally consid- ered to be a monophyletic group. Brief de- scriptions of the six lymnaeacean families are given below: Chilinidae H. & A. Adams, 1855—This is a monogeneric family erected to accommodate Chilina Gray, 1828. Several species have been reported from the rivers and estuaries of Chile, Argentina and Paraguay (Ageitos de Castellano & Miquel, 1980; Brace, 1983). The variation reported for Chilina is limited to shell shape and pigmentation, and radular tooth shape. Latiidae Hutton, 1882—This family includes only one species, Latia neritoides Gray, 1849, a freshwater limpet restricted to the streams of New Zealand (Burch & Patterson, 1964; Hubendick, 1962). Acroloxidae Thiele, 1931—This family of limpets is usually considered to comprise a single genus, Acroloxus, but the subgenus Pseudancylastrum is sometimes elevated to the generic level. The species A. coloradensis is found in Colorado, but the remaining spe- cies are found in Europe arid northern Asia (Hubendick, 1978). The principle variations in this family are shell shape and radular tooth shape (Hubendick, 1962). Physidae Fitzinger, 1833—Te (1978) pre- sents a recent revision of this family, in which he recognizes 48 species in four genera. Te differentiated physids on the basis of shell shape, pigmentation patterns, mantle edge shape, kidney and gizzard shape, and the Structures of the bursa copulatorix and the pe- nial complex. This family is globally distrib- uted. Lymnaeidae Rafinesque, 1815—This fam- ily exhibits tremendous variation in shell mor- phology, supporting a large number of nomi- nal genera. There also is considerable variation in anatomical traits, especially the male reproductive organs. Hubendick (1951) was unable to discern any clear pattern among anatomical traits or between anatom- ical and conchological traits. Therefore, he concluded that this family includes only two genera, the helicoid Lymnaea and the patel- liform Lanx. The family is globally distributed. Planorbidae Gray, 1840—This family rep- resents the merging of three classical fami- lies: helicoid Bulinidae Hermansen, 1846; dis- coid Planorbidae Gray, 1840; and patelliform Ancylidae Brown, 1844. In a series of papers, Hubendick (1947, 1948a, 1948b, 1955, 1964, 1978) demonstrated that these three groups are not clearly separable, but have complex interrelationships. Hubendick (1978) coined the name Ancyloplanorbidae to indicate the synthetic nature of the group. However, under Article 23 of the ICZN, Ancyloplanorbidae must be considered a junior synonym Planor- bidae Gray, 1840; the oldest of three names from the merged families. The Planorbidae are globally distributed, and there is consid- erable variation in both shell morphology and internal anatomy. MALACOLOGIA, 1990, 31(2): 259-295 LONGEVITY IN MOLLUSCS Joseph Heller Department of Zoology, The Hebrew University, Jerusalem, Israel ABSTRACT This paper compares longevity throughout an entire phylum, the Mollusca, in order to reveal common patterns underlying modes of reproduction. The comparison is based upon data gleaned from existing literature on the life durations of 547 species from marine, freshwater and terrestrial habitats. Life-spans of molluscs range from two months to two hundred years. Molluscs living up to two years, or molluscs living more than two years but reproducing during only one season, are here defined as short-lived. Many molluscs are long-lived, and bivalves are the most long-lived of molluscs. In the terres- trial and marine habitat, a short-lived mode of life is often correlated with: (1) Lack of an external shell. (2) Possession of an external shell that is semitransparent. (3) Dwelling in a microenvi- ronment that is exposed to high solar radiation and to high temperatures. (In cold environments, on the other hand, the semelparous cycle of molluscs without external shells may be stretched, over two years or more.) (4) Dwelling in an environment that is predictable to such an extent that conditions favourable for reproduction occur (for an annual species) at least once a year. (5) Very minute size (in gastropods). These generalizations apply almost fully to terrestrial and marine habitats and are partly valid in freshwater habitats. The correlation between shell absence and longevity accounts for the greatest number of short-lived molluscs. This correlation may be explained in adaptive terms: shell absence may affect age-specific mortality via growth rates; or shell-less molluscs may utilise transient food resources. The difficulty in accepting any ofthese adaptive explanations stems from the ubiquity of the relation between shell-lessness and a short life span: almost every single shell-less mollusc, over a wide range of habitats in the sea and on the land, is short-lived. The correlation may be also explained in non-adaptive terms: shell and longevity covary, so that an initial, adaptive change in the shell engenders a secondary, automatic change in the life-span. If this non-adaptive explanation is indeed valid, then the short life span of many molluscs may be a byproduct of selection on the shell rather than an independently selected trait. One major difficulty in accepting this non-adaptive explanation is that it lacks evidence at the genetic level. Whatever the explanaticn for these correlations, they can be used to calculate the approxi- mate number of short-lived gastropods. On a very broad and rough estimate, about one half of the land snail genera of western Europe may be short-lived. Key words: longevity, molluscs, reproductive strategies, morphology, adaptation, non-adap- tation, size, radiation. INTRODUCTION In this paper, | compare longevity through- out an entire phylum, the Mollusca. To the best of my knowledge this topic has previ- ously been examined only twice, by Comfort (1957, 1964). On a more limited taxonomic range however, Zolotarev (1980) described the life spans of many bivalves from the Sea of Japan, and Powell & Cummins (1985) sur- veyed the longevities of some marine benthic prosobranchs and bivalves. Records of the length of time a mollusc 259 lives are occasionally documented in ecolog- ical studies devoted to exploring the life his- tories of single species, or of several species within one genus. Frequently these data are presented in an incidental manner that does not relate to any larger evolutionary trends. Here, | collate data from existing literature to examine whether any general patterns of lon- gevity can be traced throughout the entire mollusc phylum. Methods of determining the age of molluscs include counting of growth checks in the shell (sometimes by shell-sectioning to reveal in- 260 LONGEVITY IN MOLLUSCS ternal growth lines), population sampling, and the recapturing of marked animals. Infre- quently the age is also determined by isotopic analysis of the shell (e.g. Turekian et al., 1975), and very infrequently by use of spec- tral analysis and flame photometry, or com- plex ionometric titration (Krasnov et al., 1975). The assembling of longevity data de- termined by any of these methods into com- prehensive tables is a simple, straightforward process. For the purposes of this study, | have ag- gregated all molluscs into two categories: short-lived (SL) and long-lived (LL). Short- lived molluscs are all those species that live up to two years, and also all those species that, regardless of how long they live, breed only over one season in their lifetimes. In con- trast, long-lived molluscs are all those species that live for more than two years and breed over two seasons at least. These two cate- gories can be compared to Kirkendall & Stenseth’s (1985) classification of reproduc- tive strategies. All their uniparous, unisea- sonal and biseasonal molluscs fit into my short-lived category, whereas all their multi- seasonal iteroparous molluscs that live for more than two years are included in my long- lived category. The present classification overcomes sev- eral entanglements arising from the fact that in some semelparous molluscs the life-span is variable, being annual in one habitat but stretching over several years in another be- cause of a colder environment. When bearing in mind that life spans of molluscs range from several months to over two hundred years, the differences that this classification over- looks, in longevity amongst molluscs living up to two years, are minor. On the other hand, one of the disadvantages of this classification is that it lumps together, within the short-lived group, iteroparous molluscs that produce only a dozen progeny with semelparous species that produce many millions. | shall return to discuss this point later. К is suggested that when analysing the data, the lowest group of long-lived molluscs, those with life-spans of 2-3 years, be sepa- rated as an intermediate category, to be ex- cluded from later calculations. By doing so we avoid a situation whereby molluscs living three years but reproducing twice are classi- fied as long-lived, whereas those living three years and reproducing once (such as certain cephalopods) are classified as short-lived. | do not think that this intermediate category bears any biological uniqueness as compared to the short- or the long-lived categories. With 60,000 Recent species, molluscs form the second-largest phylum within the animal kingdom. Longevity determines the number of seasons in which many of these species (the iteroparous ones) will reproduce. What are the life histories of molluscs? Which are the short-lived ones? Why is it that of two mollusc species living in the same environment and in very close proximity, feeding in a similar way and predated by similar enemies, one is short-lived and the other long-lived? These are the questions addressed in this paper. METHODS The available literature was searched, and each species classified as short- or long- lived. Comfort (1957) reviewed the literature on the life duration of 135 molluscs. However, many of his records are of observations on captive specimens. This present paper there- fore considers his data only to the extent that they refer to natural populations, to taxa traceable to the generic level (at least) in to- day’s taxonomy, and to those for which no more recent records could be found. Some of the literature on freshwater gastropods (Calow, 1978; Browne & Russel-Hunter, 1978) bears conflicting evidence in that spe- cies listed as semelparous by one may be listed as iteroparous by the other. This re- flects the fact that within a species, some populations may be semelparous, others iteroparous or “quasi-iteroparous” (a gener- ally semelparous population that develops iteroparity under special circumstances). To ‚ overcome this difficulty, | have arbitrarily clas- sified in this paper as short-lived any species that is enlisted as semelparous or quasi- iteroparous by at least one of these authors. Tables 1-6, in the Appendix, present the maximum number of years a species lives, as recorded in the literature. Many authors de- scribe various species as living “at least” a certain number of years. These minimum es- timates of longevity are here presented as the life-span of the species, without further com- ment. The life-spans of short-living species are presented in these tables as SL, without further detail. As there is aclose relation between the age at maturity and longevity among limpets (Branch, 1981), opisthobranchs (Todd, 1981), HELLER 261 OPISTHOBRANCHS 1 MARINE | FRESHWATER | BIVALVES | BIVALVES 80} go! 4 | 60 60! % | % | = | 404 26! 2 РА 9 YA 20 of | A РА 3 VA AV y= VA Р 4 | ZY ZA | St DAME NO! ic a LLC LL < VAE С ne ; CEPHAL OPODS | 2 4 6 8 10 1214 — YEARS MARINE ] | PROSOBRANCHS À 804 ] | 8 PULMONATES | 604 co} 6 | % 1 40} a | 2 7 р RCE | 20} | ZF 7 | C= 1 р Я St 46 в 10 1 4 7 ; 7 YEARS ein FRESHWATER LAND SNAILS à SNAILS 804 80 1 60+ 4 ob o À E i % м 77 40 ] 1 р j D | | 7 Y TA r 1 OB Gy EEE FA WF VIII I , ] | ] Е FENG st De 6 8 10 12 14 z ARS O YE FIG. 1. Life-span frequencies in various mollusc groups. SL, short-lived category. In each histogram the highest (right-most) life-span category includes all species that live 14 years or more. Data from Tables 1-6. land snails (Baur 4 Bengtsson, 1987) and, presumably, other mollusc groups, this trait is not presented in this paper. LONGEVITY DATA Fig. 1 illustrates the frequency of life spans in some various mollusc groups. Chitons Chitons are exclusively marine. Very few reliable data are available on their longevity, especially since Glynn (1970) severely criti- cised methods used by early workers in de- termining life spans. The only acceptable records | could find are of Cryptochiton stel- leri, which lives for at least 25 years (MacGin- itie & MacGinitie, 1968), and of Chaetopleura apiculata, which lives up to 4 years (Grave, 1932). Gastropods Marine snails occur in two main groups, the prosobranchs and the opisthobranchs. Proso- branchs (20,000 species) are usually long- lived, whereas most opisthobranchs (about 2,000 species) are short-lived. They repro- duce continuously once they reach sexual maturity, the frequency of their egg laying varying from several times per day to once every three weeks. They eventually die as a result of a senescent syndrome, typified by the shrinkage and breakdown of the digestive gland (Thompson 1976; Hadfield & Switzer- Dunlap, 1984). For nudibranchs (the largest group among the opisthobranchs), Todd (1981) distinguished three somewhat arbi- 262 LONGEVITY IN MOLLUSCS trary life-history patterns: (1) subannual spe- cies (life spans of a few weeks to a few months) are mostly small aeolids that feed on ephemeral prey, mainly hydrozoans; (2) an- nual species are larger (e.g. mostly dorids) and eat animals that persist in time, such as sponges, barnacles, bryozoans; and (3) bien- nial species are large animals (a few den- dronotaceans and dorids) that feed on large, long-lived prey, such as alcyonarians. How- ever, Hadfield & Switzer-Dunlap (1984) sug- gest that there is probably a continuum in the distribution of opisthobranch life spans, from species with life spans of a few weeks, through those with intermediate life spans of months, to others living one year or more. A few marine snails belong to the pulmonates, here represented by one family, the Sipho- nariidae, which are long-lived (Powell & Cum- mins, 1985). Considering only the prosobranchs from among the marine gastropods, | found (Table 1) records for 105 species belonging to 52 genera and to 30 families. This amounts to about 2% of the 2,900 Recent genera (see Taylor & Sohl, 1962). For the opisthobranchs, | found records of 63 species belonging to 37 genera and 25 families. This amounts to about 7% ofthe 500 Recent genera of opisthobranchs (see Taylor & Sohl, 1962). All are short-lived. Of the marine pulmonates, | found records of three species, all belonging to one genus. Freshwater snails belong to one of two ma- jor groups, the pulmonate basommatophorans and the prosobranchs. Most basommatopho- rans are short-lived. They are annual and semelparous, with complete replacement of generations after breeding in late spring or early summer. However, although this is the basic pattern, closer observation shows much : variation. One such deviation from the basic pattern is the production of a second summer breeding generation without replacement of one generation by the other. Another deviation is production of two generations per year, with complete replacement. Sometimes there can also be three generations, again, with or with- out replacement. Lastly, a perennial, often bi- ennial, pattern also occurs, with each gener- ation capable of reproducing in two successive years. Such patterns of intraspecific variation in life histories are common amongst fresh- water pulmonates and might be due either to ecological effects, genetic divergence, or toa combination of these factors (Russell-Hunter, 1978). In the freshwater pulmonate Lymnaea elodes for example, intraspecific variation in life histories appears to be the result of phe- notypic plasticity rather than of genetic differ- ences (Brown, 1985). Freshwater proso- branchs tend to be more long-lived than freshwater pulmonates (Calow, 1978; Brown, 1983; Geraerts & Joosse, 1984). Freshwater prosobranchs also have smaller clutch sizes, lower growth rates, smaller shell sizes at ma- turity and larger shell sizes at death (Brown, 1983). Both Calow (1978) and Geraerts & Joosse (1984) suggest that semelparity is a response to the harsh freshwater conditions that make it necessary to confine the whole embryonic development within the protecting egg mass. This procedure demands an increased repro- ductive effort but increases the chance of embryonic survival, and hence diminishes the need for a long adult phase as an insur- ance policy. Both studies suggest that this semelparous condition is associated with re- productive recklessness, in that the parents continue low reproductive activity under ad- verse conditions despite fatal effects, where- as in iteroparous species reproduction stops quickly and the available energy is saved for survival. Both also comment that freshwater snails with an iteroparous strategy are those that inhabit small, closed water bodies, where there is more competition, more density-de- pendent control, and hence a greater pre- тнт on the survival of a large, “ехреп- enced” adult. | have found records of 60 species belong- ing to 29 genera and 11 families (Table 2). Both prosobranch and pulmonate freshwater snails have, on the whole, short life-spans as compared to marine snails (Table 1) and ter- restrial ones (Table 3). Land snails belong to one of two groups, the prosobranchs (mostly confined to the tropics) and the (mostly stylommatophoran) pulmonates, which are distributed world-wide. | could not find records concerning the lon- gevities of terrestrial prosobranchs, but for the vague statement that Pomatias elegans is “said to live 4—5 years” (Fretter & Graham, 1978). The reproductive strategies of terres- trial pulmonates have been reviewed by Dun- can (1975), who emphasized that maturation and growth of stylommatophorans are tem- perature-dependent, and suggested that small helicids mature more quickly and have a shorter life span than large species. | found records of 75 species belonging to 57 genera and 30 families (Table 3). With an HELLER 263 overall estimate of 2,200 stylommatophoran genera (Taylor & Sohl, 1962), this is 3%. Bivalves Marine bivalves are represented by a very large array of groups. | found records of 150 species belonging to 90 genera and 37 fam- ilies (Table 4). This amounts to about 6% of the 1,400 Recent genera (data from Vokes, 1967). Many of these records come from the study of Zolotarev (1980), who found that half of the species examined from the Sea of Ja- pan have life spans of more than 20 years. Most freshwater bivalves belong to two families, the unionids (in which the juveniles undergo a parasitic stage in fish) and the sphaeriids (in which the young are brooded in the mother’s body, emerging as miniatures of the adult). | found records for 52 species be- longing to 17 genera and to five families (Table 5). This amounts to about 4% of the 400 genera of Recent freshwater bivalves (data from Vokes, 1967). Cephalopods There are about 650 species of cephalo- pods, belonging to 140 genera (Voss 1977). | found (Table 6) records for 27 species be- longing to 17 genera and to nine families. This amounts to about 12% of the 140 genera of Recent cephalopods. Except for one (Nau- tilus, which lives for well over 20 years; Saun- ders, 1984), all cephalopods are short-lived, reproducing through one season only, and death is the typical consequence of egg lay- ing or mating (Arnold & Williams-Arnold, 1977: Wells & Wells, 1977; Calow, 1987). According to Calow (1987), the failure of cephalopods to take advantage of the wide variety of reproductive tactics used by other mollusc groups is a consequence of selection for fast growth rates in the juveniles. He sug- gested that rapid growth would reduce the likelihood of juvenile mortality due to preda- tion, because juveniles would be small and vulnerable for a shorter time. This, in turn, would make high adult investments in repro- duction and semelparity less risky because the probability of offspring survival would be high. They seem to “live fast and die young.” Theoretical predictions that the level of invest- ment in reproduction by semelparous organ- isms should be high, that reduced levels of investment in reproduction should extend the lives of parents, and that the survival of juve- niles should generally be good, are probably not valid in cephalopods (Calow, 1987). Moy- nihan 8 Rodaniche (1982) have suggested that semelparity, when it is followed by the death and disappearance of breeders, may be an effective discouragement to specializa- tion by predators; it also leaves more re- sources for the offspring. DATA ANALYSIS Tables 1-6, with data on 547 species, clearly demonstrate the enormous variability in longevity of the molluscs: from several months to well over two hundred years. These tables also demonstrate that short life spans are a very common strategy amongst molluscs. Our present state of knowledge is ripe to discuss the short-lived category, because it is usually based upon clear-cut, firm evidence that gives the species a definite life span, plus or minus one or two years (at the very most). Our knowledge on the long-lived group is still insufficient to en- able analysis of variation within this category, because many of the data refer to information on minimum life spans rather than to actual longevity in nature. Our data are sufficient, however, to analyse and compare the short- lived group, as a whole, to the long-lived one, as a whole. The intermediate category (consisting of species with life-spans of 2-3 years, as de- fined in the introduction, and amounting to 7% of the species listed) can now be excluded from calculations. The resulting picture is summarised in Table 7. At the level of both species and genus, almost half of the records are of short-lived molluscs. As a rule, all species within one genus are either long- or short-lived. (Exceptions to this rule are the marine prosobranchs Acmaea, Littorina and Cerithium and the marine bi- valve Donax.) This fact enables a stepping-up of the taxonomic level to that of genera. By doing so, we gain a firmer taxonomic ground. We also overcome the danger of distortion due to the fact that in certain genera very many species have been studied, and are thus over-represented in the literature. Are there any morphological or environ- mental factors in which the short-lived genera differ from the long-lived ones? Should this high frequency of short-lived genera be con- sidered as a representative picture of the mol- 264 TABLE 7. Number of short- and long-lived molluscs LONGEVITY IN MOLLUSCS SHORT-LIVED LONG-LIVED CHITONS = = 2 genera, 2 species MARINE SNAILS Prosobranchs 16 genera, 25 species 36 genera, 73 species Opisthobranchs 37 genera, 63 species == = Pulmonates == = 1 genus, 2 species FRESHWATER SNAILS 23 genera, 48 species 3 genera, 6 species LAND SNAILS 30 genera, 44 species 22 genera, 26 species MARINE BIVALVES 11 genera, 21 species 73 genera, 116 species FRESHWATER BIVALVES 4 genera, 19 species 12 genera, 28 species CEPHALOPODS 16 genera, 26 species 1 genus, 1 species TOTAL: 137 genera, 246 species 150 genera, 254 species Notes to Table 7: 1. “Long-lived” refers only to molluscs that live four years or more. “Short-lived refers to molluscs that live up to two years, and also to those that reproduce throughout one season only, regardless of their life-span. 2. The data are from Tables 1-6, and from the text. 3. In the marine prosobranch category, the “mixed” genera Acmaea, Notacmea, Littorina and Cerithium are counted twice: as short- and as long-lived. luscs in general? The following sections ex- plore these questions. Longevity and shell morphology Could it be that the life-span of a mollusc is associated with the presence or absence of a well-calcified external shell? To answer this question, each genus was classified into one of three shell categories: shell fully calcified and opaque; shell consist- ing mainly of conchiolin, with very little cal- cium in it and semi-transparent; shell reduced to such an extent that the snail cannot retract into it, or that it is internal or totally absent. Most terrestrial and marine molluscs fall eas- ily into either of these three categories, but there is, of course, a continuum between the opaque and semitransparent shells, and the distinction between the two is, to a certain extent, arbitrary. The results are given in Table 8, which pre- sents the shell morphology in long-lived (ex- cluding the intermediate category) and short- lived molluscs. In marine prosobranchs, only two genera, Enteroxenos and Thyonicola, lack an external shell, and only Lacuna and Patina have a semitransparent one. All other marine proso- branchs have opaque, well-calcified shells. It is unfortunate that no data are available on the Lamellariidae and the Heteropoda, two other groups of shell-less prosobranchs. The majority of opisthobranchs listed in Ta- ble 1 are shell-less. Genera with semi-trans- parent shells are Limacina, Cavolina, Clio, Creseis, Cuvierina and Diarca. The only ge- nus with an opaque, external calcified shell is Pupa. Land snails belonging to the shell-less cat- egory include Arion, Bielzia, Catinella, Dero- ceras, Eucobresia, Limax, Milax, Omalonyx, Parmacella, Semilimax, Testacella, Vaginulus and Vitrina. Those belonging to the interme- diate category, with semitransparent shells, include Aegopinella, Carychium, Elona, Mo- nacha and Oxychilus. All other genera have opaque, external shells. Comfort (1957) men- tions Geomalacus as living seven years, based upon animals studied in captivity. If this observation does indeed reflect longevities in natural populations and if, on the other hand, the weak evidence for a short life span in Veronicella is valid, then for shell-less snails the ratio between short-lived and long-lived genera would be 15:2 (as compared to gen- era with opaque shells, where the ratio is 12: 21). Cochlicopa and Euconulus are not in- cluded in Table 2 because our present knowledge of their longevities places them within the intermediate group. If they do in- deed live more than three years, then for semitransparent snails the ratio between short-lived and long-lived genera would be 4:2, an intermediate position between the shell-less and the opaque-shelled landsnails. Most marine bivalves are well-calcified. The only totally naked marine bivalve is Chlamydoconcha (Chlamydoconchidae), in which the shell is completely enclosed by the mantle. No data on its longevity were found. Shipworms (Teredinidae) are virtually shell- НЕВЕЕВ 265 TABLE 8. Relation between shell and life span in mollusc депега SSS A. MARINE SNAILS (PROSOBRANCHS) SHELL B. MARINE SNAILS (OPISTHOBRANCHS) SHELL C. LAND SNAILS SHELL D. MARINE BIVALVES SHELL E. CEPHALOPODS SHELL LIFE-SPAN short-lived long-lived opaque 12 36 semitransparent 2 -- no external shell 2 — opaque 1 ES semitransparent 6 — no external shell 30 — opaque 12 21 semitransparent 4 — no external shell 12 1 opaque 9 74 semitransparent — 1 no external shell 2 — opaque — 1 semitransparent — — no external shell 16 = less, with a body that resembles a worm: The shell is greatly reduced, has lost its protective function and become an effective drilling tool for boring into wood. Soft-shelled clams (Mya and Panopea) have large siphons that are permanently extended, being much too large to be accommodated within the shell. How- ever, their valves are large, opaque and cal- cified to such an extent that | have placed them in the opaque category. The major semitransparent family is the Pinnidae (fan mussels), in which the valves consist largely of flexible organic conchiolin. Although Pinna atropurpurea (=P. bicolor) may perhaps be annual in Hong Kong (Wu, 1985), in Australia it lives substantially more than three years, and may well reach 12 years of age (Butler & Brewster, 1979). There are about 150 genera of cephalo- pods (Voss, 1977). Except for one (Nautilus, which has an external, calcified shell), the shell of all cephalopods is internal and re- duced (squids), or absent (octopuses). The statistical analysis of the data was car- ried out twice, and Fischer's exact test for in- dependence in 2 x 2 contingency tables (Sokal & Rohlf, 1981) was applied in both cases. First, for simplicity, the three shell cat- egories were lumped into two: shell present (categories 1 and 2) and shell absent (cate- gory 3). The frequency of the shell-less gen- era among the short-lived molluscs was sig- nificantly higher than their frequency among long-lived ones, among marine gastropods (prosobranchs alone, or prosobranchs and opisthobranchs combined), land snails and cephalopods. The frequency of shell-less genera that are short-lived is significantly higher than those that are long-lived (P = 5.1 x 10 *', Fisher's exact test). Next, categories 1 and 2 were separated and the Fisher’s exact test again applied. The frequency of genera that have semitranspar- ent shells among the short-lived molluscs is significantly higher than among the long-lived ones, in marine gastropods (P = 0.0405) and land snails (P = 0.0380) separately, and for marine and land snails combined (P = 0.0013). Amongst marine bivalves, there are no significant differences. To sum up Table 8, out of 49 mollusc gen- era without an external shell, 99% are short- lived; of 13 mollusc genera with a shell that is external but poorly calcified, 92% are short- lived; and of 165 genera with an external, well-calcified shell, only 21% are short-lived. The only freshwater shell-less molluscs | know of are the acochlidiacean genera Aco- 266 LONGEVITY IN MOLLUSCS TABLE 9. Relation between shell morphology and habitat type fully-exposed HABITAT not fully-exposed LONG-LIVED LAND SNAILS shell solid shell transparent or absent SHORT-LIVED LAND SNAILS shell solid shell transparent or absent chlidium and Tantulum, found on a few is- lands in the Pacific and on one island in the Caribbean (Rankin, 1979). | found no data on their longevity. Shipworms, though normally requiring marine conditions for successful spawning, are occasionally recorded from in- land waters (Nair & Saraswathy, 1971). Freshwater molluscs are not represented in this calculation since their classification into calcified versus semitransparent genera runs into difficulties. Apparently some individuals within a genus may be opaque and others semitransparent. Whereas in Israel many genera are semi-transparent (Valvata, Bithy- nia, Hydrobia, Semisalsa, Pseudamnicola, Galba, Stagnicola, Radix, Ancylus, Ferrissia, Bulinus, Planorbis, Segmentina, Gyraulus, Bi- omphalaria, Helisoma, Physella, Pisidium), in Europe or North America these same genera may be opaque. It is unfortunate that much of the taxonomic literature does not refer to this trait in sufficient detail. A very welcome ex- ception is the study of Fretter & Graham (1978), who describe the following freshwater prosobranchs as semitransparent: Pota- mopyrgus, Pseudamnicola, Bithynia. As for Viviparus, V. contectus is described as semi- transparent and V. viviparus as opaque. As for Viviparus ater, snails from Lake Maggiore have partially dissolved shells whereas those of Lake Zurich do not (Ribi & Gebhardt, 1986). Since | am not confident that the clas- sification of genera or even species into opaque and semitransparent categories is consistent amongst freshwater molluscs, they (and the amphibious genus Succinea) are omitted from the present analysis. Omitting the snails is not very significant because most of them (88% of the species) live less than 4 years anyway, regardless of whether they be- long to the first shell category or the second. As concerning bivalves, however, this is rather unfortunate, because their longevities in freshwater range from less than one year to № о — —k © well over a century. It should at least be noted that all long-lived genera of freshwater bi- valves are unionids, and are well-calcified— what one would indeed expect from the lon- gevity pattern in the marine and terrestrial environments. Land snails: Life span and habitat Whereas amongst marine molluscs the ma- jority of short-lived genera are shell-less or with semitransparent shells, amongst terres- trial molluscs over 35% of the short-lived gen- era have well-calcified shells. Further infor- mation concerning these genera is gained when their habitat is considered. To examine whether the life-span of a terrestrial snail is associated with the environment in which it lives, and whether short-lived genera occupy a different micro-habitat than that of the long- lived ones, each genus was classified into one of two habitat categories (as described in literature): (1) Genera frequently exposed to heavy solar radiation. This includes molluscs that sit out on the tips of the vegetation, where they are fully exposed to the sun even when aestivating. (2) Genera not exposed to solar . radiation, or found in habitats with intermedi- ate exposure to the sun. This includes all gen- era that are crevice-dwellers, litter-dwellers, or that sit in the more concealed, shady parts of vegetation or on shady parts of trees. The results are given in Table 9. Long-lived land snail genera that sit out on the vegetation include Cerion. Intermediate genera (not presented in Table 8) include Tro- choidea. Short-lived genera include Brephu- lopsis, Bulimulus, Catinella, Cernuella, Heli- cella, Monacha, Theba and Xeropicta. Statistical analysis of the data given in Ta- ble 9 reveal that the frequency of the species that are both exposed and calcified among the short-lived land snails is significantly higher than the frequency of the species that HELLER 267 are both exposed and calcified among the long-lived ones (Р = 0.0672, by Fisher's ex- act test). Life span and shell size Ten of the gastropods with opaque shells surveyed in this study are very minute (i.e. the reproducing adult is less than 4 mm). Amongst the land snails, Carychium is less than 2 mm, Vertigo less than 3 mm, and Punctum less than 2 mm. Amongst marine prosobranchs, Rissoa parva is 3-4 mm, Ske- neopsis reachs 2 mm, Omalogyra 1 mm, Ris- soella 2 mm, Barleeia 3 mm, Littorina ne- glecta reaches 2-3 mm, and Littorina acutispira usually up to 2 mm. All are short- lived. DISCUSSION The data presented so far allow for state- ments about several patterns of longevity among molluscs. One general pattern concerns the associa- tion between the loss of a mollusc’s calcified shell on the one hand and its short life-span on the other. Molluscs in which the shell has become internal or lost, and frequently also in those in which the shell is external but has lost its calcification or becomes rudimentary, are short-lived. This relationship holds true whether the mollusc is a gastropod (proso- branch, opisthobranch or pulmonate) or a cephalopod; whether it lives in the sea or on the land; whether its mode of reproduction in- volves gonochorism or hermaphroditism, planktonic larvae or hatchlings that resemble adults; whether it moves by crawling, jet-pro- pulsion or is sedentary; and whether it feeds as a herbivore, carnivore or omnivore. Describing correlations is one thing, ex- plaining them is another matter. Correlations can be explained in many ways, and the ap- proach may be adaptive or non-adaptive, each with its drawbacks. The relation between shell absence and longevity may be explained in adaptive terms, in that shell absence affects age-specific mor- tality directly. It enables high growth rates and juveniles of shell-less molluscs grow to adult size quicker than shelled ones, speeding through the vulnerable juvenile phase. Once they reach adult size their survival chances are similar to those of their parents, and since semelparity is favoured whenever the survival chances of the parents and offspring are sim- ilar (Calow, 1981), semelparity will eventually indeed develop. Differences in growth rates between shelled and shelless molluscs do exist. Among terrestrial molluscs for example, a slug such as Deroceras reticulatus matures within the first year, breeds in the second and then dies (Runham & Hunter, 1970), whereas a shelled landsnail such as Arianta arbusto- rum matures within two years, breeds and may then live on for another ten (Baur & Raboud, 1988). Similarly among cephalo- pods, a 120 mm-long squid can mature at the age of six months (Moynihan & Rodaniche, 1982), whereas Nautilus matures within sev- eral years. From these aspects, the consis- tently faster growth rates of the shell-less mol- luscs may indeed be an advantageous trait. Whether these rapid growth rates should always and consistently lead to semelparity is another question. Such an argument would imply ubiquity in the ecology of entire groups of shell-less molluscs, which is difficult to ac- cept. It is not reasonable to assume that all 2,500 molluscan species—which have had different taxonomic origins ever since the Palaeozoic, which live in environments as dif- ferent as a whole spectrum of habitats in the sea and on land, which practice a wide scope of reproductive strategies ranging from plank- tonic veligers to direct development (with or without parental caring of eggs), which are either hermaphroditic or gonochoristic— should always and consistently practice a semelparous reproductive strategy only be- cause, since they enjoy a faster growth rate, their survival chances come to resemble those of their parents at an earlier age. The advantages to be gained from semelparity must surely be overwhelming if such a gen- eral correlation, cutting through an entire an- imal phylum, should be explained on its se- lective basis. Another, somewhat similar adaptive ap- proach to the relation between shell absence and longevity could be that when extrinsic mortality risks (such as starvation, accident, disease or predation) are higher for parents than for offspring, it pays the parent to in- crease its investment in the reproduction of many offspring. This increase would eventu- ally lead to a semelparous reproductive strat- egy (Calow, 1981, 1984). As applied to mol- luscs, this means that shell absence directly affects age-specific mortality: If the shell-less mollusc (slug, octopus or opisthobranch) 268 LONGEVITY IN MOLLUSCS were to live on after reproduction, then its sur- vival chances would be very low as compared to its progeny, due to such environmental fac- tors. This age-specific-mortality argument can definitely be applied to many opisthobranchs, in which the parent feeds upon food that is transient, whereas the juveniles feed upon another source. Thus in Aplysiamorpha and Sacoglossa, the adult feeds upon seasonally abundant green seaweed, whereas the juve- nile is a planktonic veliger that feeds upon unicellular algae (Kandel, 1979; Carefoot, 1987). Among the bivalves, shipworms offer another excellent example of a mollusc utiliz- ing a transient habitat. They have rapid growth rates, reach an early maturity within 3-6 weeks and have very high reproductive rates (Nair & Saraswathy, 1971; Turner, 1973). Again however, whether shell-less mol- luscs always and consistently feed upon tran- sitional prey is another question. Opistho- branchs feed upon a wide variety of prey (hydrozoans, sponges, polychaetes, gastro- pods, bivalves, ascidians, sessile barna- cles—see Thompson, 1976), and many of these food resources are rather stable and not of a transient nature. Octopuses and cut- tlefish are opportunistic carnivores that feed upon shrimps, prawns, crabs, polychaetes, bivalves, gastropods and fishes (Boucaud- Camou & Boucher-Rodoni, 1983), food re- sources that are stable rather than transient. Slugs eat dead leaves, stems, bulbs, tubers, fungi, lichens and algae (Runham & Hunter, 1970), a diet similar to that of shelled land- snails. It is questionable whether all of these food resources are indeed transient, but even if they are, this does not explain the question but merely rephrases it into “why are the shell-less molluscs, whether herbivores, om- nivores or carnivores, capable of feeding only upon transient, rather than stable re- sources?” This is back almost to the starting point. Extrinsic mortality risks include also preda- tion, and it could perhaps be argued that groups in which the extent of predation in- creases with adulthood are likely to be short- lived. To make such a claim acceptable, some sort of evidence must be presented that shows that in nature, predation pressures on adult shell-less molluscs are indeed greater than those on their progeny, thereby lowering their survival chances. Together with such data, additional evidence must also be pre- sented that adult shelled molluscs do not face such severe predation risks. At present, | do not know of such evidence. To conclude, it should be re-emphasized that the question emerging from the data analysis is not whether some molluscs are short-lived, but why all shell-less molluscs are short-lived. The disadvantage of the adaptive approach is that it does not cope with the ubiquity of the relation between shell and lon- gevity, and when the whole spectrum of shell- less molluscs is considered, it loses much of its attractiveness. The ubiquity of the relation may be ex- plained in non-adaptive terms: A short life span may be a byproduct of selection on the shell, rather than an independently selected trait. Shell and longevity may covary so that an adaptive change in the shell engenders an automatic switch in longevity, the latter being irrelevant to adaptation and not under imme- diate control of the environment. Loss of the shell occurred independently in several molluscan lineages, as a result of a wide variety of selective forces that, at least as considered today, have very little to do with life cycles. In marine prosobranchs, predatory pressure by crabs and fish has resulted in the survival of heavy, ridged or spiny shells (Ver- meij, 1978). Pressure on marine cephalopods to form a very light, buoyant animal capable of swimming actively in the water body (rather than passively drifting with the currents in a flying-balloon, Nautilus-style) has led to the persistence of those with an internal shell, or with no shell at all. Opisthobranchs' initial ex- ploitation of the infaunal (burrowing) environ- ment by the primitive order Bullomorpha, combined with their development of chemical defence supplied by the integument to re- ‚ place the mechanic defense supplied by the shell, led to the reduction of the shell and its eventual loss (Thompson, 1976). In such planktonic opisthobranchs as the Euthecoso- mata, a (transparent) shell is retained, how- ever, and functions as a retreat into which the animal withdraws, so as to sink and thereby rapidly avoid predators (Be & Gilmer, 1977). In terrestrial molluscs, the ability for deeper penetration into the ground and, in addition, the invasion of calcium-deficient, moisture- rich environments has been the outcome of developing a shell-less slug form in several unrelated taxonomic families (Solem, 1978). Alternatively, the slug form may have devel- oped through the habit of climbing up trees (Cain, pers. comm.). Once the shell is lost, in HELLER 269 any of these mollusc lineages and for any of these selective reasons, a mollusc will auto- matically become short-lived. Within the severe limits of a short life span, life history strategies vary in evolutionary re- sponse to different environmental conditions. For example, some of the species of British nudibranchs have fully annual life cycles with one breeding period, whereas others pass through numerous generations a year. The purely annual species feed on organisms that are abundant and stable throughout all sea- sons of the year, whereas those passing through a number of generations a year are species that feed.upon seasonal, transitory prey (Thompson, 1976). Seasonal food short- age may thus determine the relatively short life span of the one, as compared to a stable food supply that determines the slightly longer life span of the other. However, both have an overall short life span that does not exceed one year, two atthe most. When we consider them together, as one single category, in comparison to the long-lived (and shell-pos- sessing) prosobranchs, these differences be- tween them seem trivial. This non-adaptive approach may suggest that shell absence is the overriding factor in determining whether a mollusc will be short- or long-lived. Once this major factor is set and the mollusc becomes short-lived, then environmental factors deter- mine the fine tuning. The non-adaptive approach may suggest (in a very schematic and over-simplified manner) that many molluscs, short-lived because they lost their shells, invaded the “transient food niche” where there is less competition from the long-lived (shelled) molluscs. However, a tran- sient food niche is not a prerequisite of shell- lessness, and many short-lived (shell-less) molluscs may enjoy a stable food niche, their short life-spans bearing no direct relevance to their food resources (and vice-versa). The advantage of this non-adaptive ap- proach is that it copes well with the ubiquity of the relationship between shell absence and short longevity. One severe weakness of the non-adaptive approach is that it requires a nearly single- gene linkage between shell-lessness and lon- gevity. There is, as yet, no direct evidence for any such link. A further weakness is that it cannot explain exceptional records, of shell-less molluscs that are not short-lived. This includes the ter- restrial slug Testacella, if we restrict ourselves to longevity records based upon evidence from natural populations. If also records of molluscs reared in captivity are accepted, then this also includes the landsnail Geoma- lacus (Comfort, 1957). Data on the longevity of slugs from additional pulmonate families, such as the Helicarionidae, Charopidae, Athoracophoridae and Endontidae, could also help, since long life spans in these families would weaken the non-adaptive approach considerably, at least as a phenomenon that sweeps through the entire phylum. It should be emphasized that whereas for gastropods we have data on 45 shell-less gen- era, for bivalves we have data for only two. Both are short-lived, but this is obviously not nearly enough to enable generalisations about the entire class. A reminder as to why (in this respect) the bivalves should be approached cautiously comes from Nausitora fusticula, a large oviparous teredinid of tropical man- groves. Collected as a fully grown adult (age unknown), а specimen of this species lived for two and a half years in an aquarium at Harvard University (R. Turner, pers. comm.). To conclude, the disadvantages of the non- adaptive approach is that it lacks, as yet, ge- netic support and that it relies very heavily upon the ubiquity of the association, so that it cannot explain exceptions. A second pattern to emerge from the data in this study is that the life history of well- calcified molluscs is influenced by the tem- perature of their environment. A short life- span may occur in well-calcified molluscs that live in very hot environmental conditions. The rate of gamete development is directly depen- dent on temperature, and high temperatures increase the rate of gonad maturation. The scallop Argopecten irradians, for example, matures within 12 months in its natural habi- tat, but maturing can be accelerated by labo- ratory exposure to higher temperatures, and it then reaches reproductive stage within six months (Sastry, 1979). A warm environment will also enable the rapid growth of juvenile gastropods (see Runham & Hunter, 1970, for slugs; Geraerts & Joosse, 1984, for freshwa- ters gastropods). In the marine environment, the term hot applies to geographically wide- spread species, where populations from trop- ical waters complete their life-span in a much shorter time (Cerrato, 1980; Hadfield & Swit- zer-Dunlap, 1984). In the freshwater environ- ment, it applies to snails and bivalves that live in relatively warm waters (Geraerts & Joosse, 1984: Mackie, 1984). In the terrestrial envi- ronment, my study suggests that it refers to 270 LONGEVITY IN MOLLUSCS those micro-habitats in which the land snails sit out on the vegetation, where they are fully exposed to solar radiation. Low temperature, on the other hand, can stretch a semelparous cycle that is annual in the warmer parts of a species’ range, into a biennial one in the colder parts. (Theba pisana from Israel as compared to that of England is one such case; see Heller, 1982, and Cowie, 1984. Ari- anta arbustorum of the lower Alps as com- pared to that of higher altitudes is another example; Baur & Raboud, 1988.) The short life-span of molluscs of hot micro-habitats may be a phenotypic response to the environ- ment, or it may be a genetically controlled trait, subject to selection. In land snails, the relation between longev- ity and exposure may be explained in adap- tive terms, in that ionizing radiation increases the rate of ageing and reduces the average life-span of animals. Experimental evidence reviewed by Comfort (1978) showed that large doses of hard radiation (gamma and fast neutrons) shorten life considerably. These conclusions should be approached with caution, however, since the experiments made use of extremely heavy doses that ex- ceed natural quantities reaching the earth by several orders of magnitude. The effects of ultraviolet radiation on molluscs are as yet un- known, but upon entering a reptile’s body ul- traviolet radiation can cause a breakdown of molecules and thereby alter vital biochemical processes (Porter, 1967). A short life span could thus be enforced in landsnails dwelling on the tips of vegetation, where they are sub- ject to heavier ultraviolet radiation than snails dwelling underneath stones. Even visual day- light radiation may be an important environ- mental factor that influences the gonad of land snails. Continuous illumination of the slug Deroceras reticulatum for five weeks in- creases the thickness of the germinal epithe- lium, rate of meiosis and also the numbers of sertoli cells, male gametes, multinuculated spermatids, and it upsets in cytokinesis (Pari- var, 1978, and references therein). An exception to this generalisation that land snails of warm, strongly radiated environ- ments are short-lived concerns snails that in- habit environments that, in addition to being hot, are also extremely unpredictable, such as the shadeless vegetation of deserts. In such hot surroundings, where conditions for growth and reproduction are both very infre- quent and unpredictable, semelparous an- nual populations would quickly become ex- tinct. Molluscs of these habitats may be expected to be more long-lived than their close relatives from more favourable condi- tions. Short-lived molluscs are restricted, ac- cordingly, to environments in which there is a predictable weather. A third pattern to emerge from the data in this study is that among the shell-possessing gastropods, longevity is related to size. Though the linear relationship between body size and life-span found in mammals (Kohn, 1971) definitely does not occur in molluscs, short life spans appear to occur more fre- quently among very minute gastropods than among larger ones. Every single one of the very minute gastropods found in this study are short-lived. (This does not apply to the bi- valves, in which minute genera, such as My- sella, may live for six years.) Furthermore, to the extent that the short-lived group can be divided into semelparous animals on the one hand and iteroparous animals on the other, most of these small snails belong to the latter group: They mature within several weeks early in the season, lay several eggs (up to about 30) throughout the remainder of the season, and gradually die off by the end of the season (Fretter, 1948; Morton, 1954; Southgate, 1982; Hughes, 1986; Baur, 1987; Pokryszko, pers. comm). Littorina acutispira (see Under- wood & McFadyen, 1983) and Rissoa repro- duce by planktonic veligers, and consequently have more juveniles than the rest ofthis group. Marine gastropods that are both well-calcified, short-lived and produce a very large number of offspring (such as Cerithium scabridum; see Ayal, 1978) are infrequent. A fourth pattern to emerge is that bivalves are more long-lived than other groups. Though they form only 40% of the species ‚ listed in the longevity tables, they constitute 88% of the species that live over 25 years, 92% of the species that live over 50 years, and they are the only molluscs that live over a century. Short life-spans are not a very com- mon strategy amongst bivalves, and only 15% of the bivalve genera are short-lived (as compared to short life spans in 63% of the gastropods). A sedentary mode of life appar- ently bears the potential for a long life-span. CONCLUSIONS This paper paints the longevity pattern of molluscs in very broad strokes. To conclude, we can to a certain extent generalize about HELLER 22] the relationship between a mollusc’s longev- ity, its morphology and its environment. Bivalves are the most long-lived of mol- luscs. Amongst bivalves, prosobranchs and pul- monates, short life-spans are more common in the freshwater than in the marine or terres- trial environment. In the terrestrial and marine habitat, a short-lived mode of life is often correlated with: 1. Lack of an external shell. 2. Possession of an external shell that is semitransparent. 3. Dwelling in a micro-environment that is exposed to high solar radiation and to high temperatures. (In cold environments, on the other hand, the semelparous cycle of molluscs without external shells may be stretched, over two years or more.) 4. Dwelling in an environment that is predictable to such an extent that conditions favourable for reproduction occur (for an annual species) at least once a year. 5. Very minute size (in gastropods). Of these generalizations, the correlation between shell absence and longevity ac- counts for the greatest number of short-lived molluscs. When combined together, these correla- tions, of shell-morphology exposure and minute size, account for 84% of the short- lived marine snails, and 93% of the land snails mentioned in this study. Confining our- selves to the gastropods, we can now apply these correlations to predict, very approxi- mately, the number of short-lived genera. In the terrestrial habitat, present information concerns mainly Europe. If we combine, from Kerney & Cameron (1979), all the genera that are shell-less, have semitransparent shells, dwell in exposed habitats where they sit out on the vegetation, or are very minute (less than 4 mm) and assume that all these snails are short-lived, then as a very rough and broad estimate, half of the genera of Britain and northwestern Europe may be short-lived. Similar calculations reveal that about half of the 45 genera of the Mediterranean region of Israel may be short-lived, whereas in the Ne- gev Desert, where slugs and snails with semi- transparent shells cannot survive because of the dangers of desiccation, only one of the nine genera is short-lived and another one is intermediate. The empiric rules proposed in this paper are based upon evidence from 547 mollusc species. Future research will probably modify them considerably. ACKNOWLEDGMENTS Dr. B. Baur, Dr. M. Lazaridou-Dimitriadou, Dr. B. Pokryszko, Dr. N. Runham, Dr. Y. Steinberger and Prof. R. Turner kindly permit- ted me to quote from as-yet unpublished data. | am endebted to Dr. U. Motro for carrying out the statistics. In writing a paper that discusses longevity pattern throughout an entire phylum and re- views data of five hundred species, it is im- possible not to make errors. | thank Dr. B. Baur, Prof. A. J. Cain, Prof. P. Calow and Prof. S. Stearns for criticizing earlier versions and weeding out many mistakes. The remain- ing mistakes are all, of course, my own re- sponsibility. | owe special thanks to Mr. M. Hallel, for assisting me in the writing of this paper. LITERATURE CITED ALDRIDGE, D. W., 1982. 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Haliotidae Haliotis cracherodii 51 Powell & Cummins, 1985 Haliotis iris 10 Powell & Stanton, 1985 Haliotis laevigata 10 Shepherd et al., 1982 Haliotis ruber 10 Shepherd et al., 1982 Haliotis rufescens 13 Shepherd et al., 1982 Haliotis tuberculata 6 Hayashi, 1980a, b Fissurellidae Fissurella barbadensis 3 Hughes & Roberts, 1980a, b Fissurella crassa 10 Bretos, 1980 Montfortula rugosa 3 Powell & Cummins, 1985 Patellidae Cellana grata 15 Comfort, 1957 Cellana radiata 4 Powell & Cummins, 1985 Cellana tramoserica 5 Fletcher, 1984 Nacella concinna 21 Picken, 1980 Nacella delesserti 10 Blankley & Branch, 1985 Patella aspersa 12 Powell & Stanton, 1985 Patella cochlear 25 Powell & Cummins, 1985 Patella granatina 6 Powell & Cummins, 1985 Patella granularis 8 Powell & Cummins, 1985 Patella longicosta 16 Grahame & Branch, 1985 Patella oculus 3 Powell & Cummins, 1985 Patella vulgata 15 Comfort, 1957 Patina pellucida SL Vahl, 1971 (continued) 280 TABLE 1. (continued) Species Acmaeidae Acmaea antillarum Acmaea digitalis Acmaea dorsuosa Acmaea insessa Acmaea paradigitalis Acmaea pelta Acmaea scabra Acmaea testudinalis Notacmea petterdi Notacmea scutum Patelloida alticostata Patelloida latistrigata Trochidae Falsimargarita iris Gibbula umbilicalis Margarites helicinus Monodonta lineata Tegula funebralis Trochus niloticus Turbidae Turbo setosus Neritidae Nerita albicilla Nerita atramentosa Nerita fulgurans Nerita japonica Nerita polita Nerita tesselata Nerita versicolor Littorinidae Littorina acutispira Littorina coccinea Littorina littorea Littorina neglecta Littorina neritoides Littorina nigrolineata Littorina obtusata Littorina rudis Littorina scabra Littorina sitkana Lacunidae Lacuna pallidula Lacuna vincta Skeneopsidae Skeneopsis planorbis Omalgyridae Omalgyra atomus Rissoellidae Rissoella diaphana Rissoella opalina Rissoidae Barleeia unifasciata Rissoa parva Rissoa splendida LONGEVITY IN MOLLUSCS Lifespan wo œo Oo BR OC Oo Oo ND Authority Kenny, 1977 Choat & Black, 1979 Comfort, 1957 Choat & Black, 1979 Powell & Cummins, 1985 Powell & Cummins, 1985 Sutherland, 1970 Zaika, 1973 Powell & Cummins, 1985 Phillips, 1981 Powell & Cummins, 1985 Powell & Cummins, 1985 Egorova, 1978 Williamson & Kendall, 1981 Zaika, 1973 Williamson & Kendall, 1981 Williamson & Kendall, 1981 Smith, 1987 Sire & Bonnet, 1984 Frank, 1969 Powell & Cummins, 1985 Powell & Cummins, 1985 Comfort, 1957 Powell & Cummins, 1985 Hughes & Roberts, 1980a, b Hughes & Roberts, 1980a Underwood & McFadyen, 1983 Comfort, 1957 Hughes & Roberts, 1980b Hughes, 1986 Hughes & Roberts, 1980b Hughes & Roberts, 1980b Goodwin, 1978 Hughes & Roberts, 1980b Comfort, 1957 . Powell & Cummins, 1985 Grahame, 1977 Grahame, 1977 Fretter, 1948 Fretter, 1948 Fretter, 1948 Fretter, 1948 Southgate, 1982 Powell & Stanton, 1985 Zaika, 1973 TABLE 1. (continued) HELLER 281 Species Entoconchidae Enteroxenos bonnevie Thyonicola americana Modulidae Modulus modulus Cerithiidae Cerithium coeruleum Cerithium eburneum Cerithium lutosum Cerithium muscarum Cerithium rupestre Cerithium scabridum Diastomidae Diastoma varium Potamididae Batillaria attramentaria Cerithidea decollata Calyptraeidae Calyptraea chinensis Trichotropidae Trichotropis cancellatum Strombidae Strombus costatus Strombus gigas Strombus luhuanus Naticidae Conuber sordida Polinices duplicatus Thaididae Dicathias orbita Morula musiva Nucella lamellosa Ocenebra poulsoni Shaskyus festivus Thais clavigera Thais lapillus Urosalpinx cinerea Buccinidae Neptunea antiqua Nassariidae Bullia rhodostoma Nassarius obsoleta Nassarius reticulatus Mitridae Thala floridana Fasciolaridae Latirolagena smaragdula Vasidae Vasum turbinellus Conidae Conus arenatus Conus pennaceus Lifespan SL SL SL © ра 19 10 Authority Lutzen, 1979 Bryne, 1985 Houbrick, 1980 Ayal, 1978 Houbrick, 1974 Houbrick, 1974 Houbrick, 1974 Ayal, 1978 Ayal, 1978 Powell & Stanton, 1985 Powell & Cummins, 1985 Powell & Stanton, 1985 Comfort, 1964 Comfort, 1964 Wefer & Killingley, 1982 Wefer & Killingley, 1982 Frank, 1969 Powell & Cummins, 1985 Edwards & Huebner, 1977 Phillips & Campbell, 1974 Tong, 1986 Hughes, 1986 Fotheringham, 1971; Phillips & Campbell, 1974 Fotheringham, 1971, Phillips & Campbell, 1974 Tong, 1986 Hughes & Roberts, 1980a,b Powell & Stanton, 1985 Powell & Stanton, 1985 Brown, 1982 Comfort, 1957 Powell & Stanton, 1985 Maes & Raeihle, 1975 Frank, 1969 Frank, 1969 Powell & Cummins, 1985 Perron, 1982 (continued) 282 TABLE 1. (continued) Species Terebridae Terebra gouldi OPISTHOBRANCHIA Acteonidae Рира КИК Retusidae Retusa obtusa Limacinidae Limacina bulimoides Limacina inflata Limacina trochiformis Cavoliniidae Cavolinia gibbosa Clio pyramidata Creseis virgula Cuvierina columella Diacria trispinosa Aplysiidae Aplysia californica Aplysia depilans Aplysia fasciata Aplysia juliana Aplysia kurodai Aplysia punctata Dolabella auricularia Phyllaplysia taylori Limapontiidae Limapontia capitata Limapontia depressa Limapontia senestra Elysiidae Elysia viridis Tritoniidae Tritonia hombergi Dendronotidae Dendronotus frondosus Dendronotus subramosus Hancockiidae Hancockia californica Dotoidae Doto amyra Doto coronata Doto fragilis Doto kya Tethyidae Melibe leonia Goniodorididae Ancula cristata Goniodoris nodosa Onchidorididae Adalaria proxima Acanthodoris pilosa Onchidoris bilamellata Onchidoris depressa LONGEVITY IN MOLLUSCS Lifespan 10 SL Authority Powell & Cummins, 1985 Rudman, 1972 Thompson, 1976 Wells, 1976 Wells, 1976 Wells, 1976 Wells, 1976 Wells, 1976 Wells, 1976 Wells, 1976 Wells, 1976 Gev et al., 1984 Gev et al., 1984 Gev et al., 1984 Gev et al., 1984 Gev et al., 1984 Comfort, 1957 Pauly & Calumpong, 1984 Pauly & Calumpong, 1984 Miller, 1962 Comfort, 1957 Miller, 1962 Miller, 1962 Miller, 1962 Miller, 1962; Nybakken 1974 Nybakken, 1974 Nybakken, 1974 Nybakken, 1974 Miller, 1962 Miller, 1962 Nybakken, 1974 Comfort, 1957 Todd, 1981 Miller, 1962; Thompson, 1976 Thompson, 1976 Miller, 1962; Todd, 1981 Thompson, 1976 Todd, 1981 HELLER 283 TABLE 1. (continued) Species Lifespan Authority Onchidoris muricata SL Miller, 1962; Thompson, 1976 Onchidoris pusilla su Miller, 1962; Todd, 1981 Triophidae Triopha maculata SL Nybakken, 1978 Polyceridae Limacia clavigera SE Miller, 1962 Polycera quadrilineata SL Miller, 1962 Chromodorididae Chromodoris nodosus SL Comfort, 1957 Chromodoris zebra SL Comfort, 1957 Archidorididae Archidoris pseudoargus SL Thompson, 1976 Kentrodorididae Jorunna tomentosa SL Miller, 1962 Heroidae Hero formosa SL Miller, 1962 Coryphellidae Coryphella lineata SL Miller, 1962 Coryphella trilineata SE Nybakken, 1974 Facelinidae Facelina coronata SL Todd, 1981 Aeolidiidae Aeolidia papillosa SL Miller, 1962 Eubranchidae Eubranchus exiguus SE Miller, 1962 Eubranchus olivaceus SL Nybakken, 1974 Eubranchus pallidus SE Miller, 1962; Todd, 1981 Eubranchus rustyus SL Nybakken, 1974 Cuthonidae Catronia alpha SL Nybakken, 1974 Tergipes despectus SL Miller, 1962 Trinchesia abronia SL Nybakken, 1974 Trinchesia albocrusta SL Nybakken, 1974 Trinchesia amoena SL Miller, 1962 Trinchesia flavovulta SIE Nybakken, 1974 Trinchesia foliata SL Todd, 1981 Trinchesia lagunae SL Nybakken, 1974 PULMONATA Siphonariidae Siphonaria denticulata 6 Powell & Cummins, 1985 Siphonaria lessoni 5 Powell & Cummins, 1985 Siphonaria virgulata 3 Powell & Cummins, 1985 Notes to Table 1: Acmaea insessa lives on the kelp Egregia laevigata and must mature and reproduce within a year, before death of the alga (Choat & Black 1979). Margarites helicinus is a small topshell of Arctic oceans. The rissoacean genera Skeneopsis, Omalogyra and Rissoella are minute (about 2 mm) herbivorous gastropods of rocky tide pools. They are hermaphrodites, and Omalogyra may practice self-fertilization (Fretter, 1948). Barleeia dwells amongst filamentous red algae, where it grazes upon diatoms. Enteroxenos is a genus of greatly modified, shelless prosobranchs that live as endoparasites in aspidochirote holothurians. The population breeds throughout the year, but each female produces only one egg batch, after which she dies (Lutzen, 1979). Thyonicola americana is an endoparasite of holothurians. Evisceration in these holothurians is a seasonal (autumn) event which sheds the parasites, that then die. Minimal life span of the parasite is 6 months (Bryne, 1985). 284 LONGEVITY IN MOLLUSCS M. modulus lives upon angiosperm sea-grasses (Houbrick, 1980). Retusa obtusa feeds upon the marsh-dwelling prosobranch Hydrobia ulvae (Thompson, 1976). Limacinids and cavoliniids are are euthecosomatous pteropods, a small group of planktonic gastropods occurring mainly in tropical oceans (Wells, 1976). Onchidoris bilamellata feeds upon barnacles (Thompson, 1976). Comfort (1957) in stating that the opisthobranch Haminea hydatis lives four years, quotes Berrill (1931). | could not find evidence for this in Berrill's paper. Comfort (1957) mentions Philine aperta as living 3—4 years, an exceptionally long life-span for an opisthobranch. As | could not reach the original reference and as | do not know whether this species is iteroparous or semelparous, P. aperta is not included in this present list. TABLE 2. Life spans in freshwater snails Species Lifespan Authority PROSOBRANCHIA Neritidae Neritina granosa 7 Ford, 1987 Theodoxus fluviatilis 2 Fretter & Graham, 1978 Viviparidae Campeloma rufum 3 Van Cleave & Altringer, 1937 Viviparus ater 8 Ribi & Gebhardt, 1986 Viviparus contectoides 1-3 Van Cleave & Lederer, 1932 Viviparus georgianus 3-4 Buckley, 1986 Viviparus malleatus 5 Stanzykowska et al., 1971 Viviparus viviparus a Spoel, 1958 Hydrobiidae Amnicola limosa SL Pinel-Alloul & Magnin, 1973 Falsihydrobia streletzkiensis SL Chukhchin, 1978 Hydrobia acuta SE Chukhchin, 1978 Hydrobia pusilla SL Chukhchin, 1978 Hydrobia ulvae SL Kondratenkov, 1978 Hydrobia ventrosa SE Chukhchin, 1978 Potamopyrgus antipodarum SL Winterbourn, 1970 Potamopyrgus jenkinsi SL Winterbourn, 1970 Bithyniidae Bithynia leachi SL Fretter & Graham, 1978 Bithynia tentaculata 2-3 Lilly, 1953 Valvatidae Valvata cristata SL Fretter & Graham, 1978 Valvata humeralis SL Calow, 1978 Valvata piscinalis SL Calow, 1978 Valvata pulchella SL Zaika, 1973 Pleuroceridae Leptoxis carinata SE Aldridge, 1982 Thiaridae Brotia hainanensis 3 Dudgeon, 1982 Melanoides tuberculata SL Dudgeon, 1986 Melanopsis costata 6 Ra'anan, 1986 PULMONATA: Lymnaeidae Acella haldemani SL Calow, 1978 Austropelpa vinosa SL Blair & Finlayson, 1981 Lymnaea elodes SE Calow, 1978 Lymnaea humilis SL Calow, 1978 Lymnaea natalensis SE Fashuyi, 1981 HELLER 285 TABLE 2. Life spans in freshwater snails Species Lifespan Authority Lymnaea palustris SL Browne & Russell-Hunter, 1978 Lymnaea peregra SE Calow, 1978 Lymnaea trunculata SL Calow, 1978 Lymnaea stagnalis SL Berrie, 1965 Physidae Aplexa hypnorum SL Calow, 1978 Physa acuta SL Calow, 1978 Physa fontinalis SL Calow, 1978 Physa gyrina SL Calow, 1978 Physa integra SL Calow, 1978 Physa virgata SL Calow, 1978 Planorbidae Anisus vortex SL Zaika, 1973 Armiger cristata SL Richardot & Alfaro, 1985 Biomphalaria glabrata SL Appleton, 1978 Biomphalaria pfeifferi SE Appleton, 1978 Bulinus forskalii SL Fashuyi, 1981 Bulinus globosus SL Fashuyi, 1981 Bulinus nasutus SL Brown, 1980 Helisoma trivolis Si Eversole, 1978 Planorbis albus SL Calow, 1978 Planorbis carinatus SL Calow, 1978 Planorbis contortus SL Calow, 1978 Planorbis corneus SL Calow, 1978 Planorbis planorbis SL Calow, 1978 Planorbis vortex SL Calow, 1978 Ancylidae Ancylus fluviatilis SL Durrant, 1980 Ancylus lacustris SL Calow, 1978 Ferrissia rivularis SL Calow, 1978 Hebetancylus excentricus SL Calow, 1978 Laevapex fuscus SE Calow, 1978 Notes to Table 2: Neritina granosa is a rheophilic gastropod endemic to Hawaiian freshwater streams. The species is diadromus. The female reproduces thousands of planktivorous veligers, that accumulate at stream mouths (Ford, 1987). Campeloma is a freshwater snail of North America that breeds parthenogenetically (Van Cleave & Altringer, 1937). In Viviparus contectoides the males live slightly longer than one year, but the females live about three years (Van Cleave & Lederer, 1932). In Viviparus georgianus males live for three years, females for four (Buckley, 1986). Bithynia tentaculata lives only up to 2 years in the Bielorussian lakes (Zaika, 1973). Falsihydrobia streletzkiensis is similar to Hydrobia in various aspects of its morphology, but differs in its genitalia. Its taxonomic assignment at the family level is still unclear (Chukhchin, 1978). Leptoxis carinata, a freshwater cerithiacean of North America, is a semelparous biennial (Aldridge, 1982). Melanoides tuberculata is an ovoviviparous, usually parthenogenetic snail. In Hong Kong, studies at the population level suggest that the life span is at least one year and at the most two, with a single peak in juvenile recruitment coinciding with the warmer months (Dudgeon, 1986). However, although release of hatchlings is strictly seasonal, fully developed larvae are found in the brood pouches throughout the year. In Malaysia (Berry & Kadri, 1974) snails reach a life-span of 3 1/2 years, as extrapolated from laboratory growth rates. Melanopsis is the most common freshwater snail in Israel. Isolated pairs of M. costata were kept by Ra’anan (1986) in captivity for six years. 286 TABLE 3. Life spans in landsnails. Species Veronicellidae Vaginulus borellianus Veronicella ameghini Ellobiidae Carychium tridentatum Melampus sp. Ovatella myosotis Achatinellidae Achatinella mustelina Cochlicopidae Cochlicopa lubrica Vertiginidae Vertigo pusilla Chondrinidae Solatopupa similis Enidae Brephulopsis bidens Clausiliidae Cochlodina laminata Vestia elata Cerionidae Cerion Spp. Achatinidae Achatina achatina Achatina fulica Archachatina marginata Endodontidae Discus rotundatus Punctum pygmaeum Arionidae Arion ater Arion circumscriptus Arion hortensis Arion intermedius Arion subfuscus Succineidae Catinella arenaria Omalonyx felina Succinea ovalis Vitrinidae Eucobresia nivalis Semilimax kotulai Vitrina alaskana Vitrina pellucida Zonitidae Aegopinella nitidula Aegopinella nitens Oxychilus cellarius Oxychilus helveticus Lifespan SL SL SL SL LONGEVITY IN MOLLUSCS Authority Runham & Hunter, 1970 Dundee, 1977 Morton, 1954 Apley, 1970 Meyer, 1955 Hadfield & Mountain, 1980 Uminski & Focht, 1979 Pokryszko, 1986. Boato & Rasotto, 1987 Livshitz & Shileyko, 1978; Livshitz, 1985. Cameron, 1982 Piechocki, 1982 Woodruff, 1978 Hodasai, 1979 Mead, 1961 Plummer, 1982 Cameron, 1982 Baur, pers. comm. Runham & Laryea, 1968 Godan, 1983 Bett, 1960; Hunter, 1968 Godan, 1983 Bett, 1960 Baker, 1965 Shrader, 1974 Strandine, 1941 Uminski, 1979 Uminski, 1975 Boag & Wishart, 1982 Taylor, 1907; Uminski & Focht, 1979 Mordan, 1978 Mordan, 1978 Mordan, 1978 Cameron, 1982 TABLE 3. (continued) Species Euconulidae Euconulus fulvus Milacidae Milax budapestensis Milax sowerbii Milax gagates Limacidae Bielzia coerulans Deroceras caucasicum Deroceras reticulatum Deroceras sturanyi Limax flavus Limax maximus Parmacellidae Parmacella rutellum Bulimulidae Bulimulus dealbatus Liguus fasciatus Elonidae Elona quimperiana Testacellidae Testacella sp. Polygyridae Allogona profunda Mesodon roemeri Polygyra thyroideus Oleacinidae Euglandina rosea Pleurodontidae Caracolus caracolus Camaenidae Amplirhagada napierana Sphincterochilidae Sphincterochila prophetarum Sphincterochila zonata Helminthoglyptidae Helminthoglypta arrosa Bradybaenidae Bradybaena fruticum Helicidae Arianta arbustorum Cepaea nemoralis Cernuella virgata Eobania vermiculata Helicella caperata Helix aspersa Helix lucorum Helix pomatia Levantina hierosolyma Monacha cartusiana Monacha haifaensis Theba pisana HELLER 287 Lifespan Porn 15 10 Authority Uminski & Focht, 1979 Hunter, 1968 Bett, 1960 Focardi & Quattrini, 1972 Smolenska, 1936 Uvalieva, 1978 Godan, 1983 Kosinska, 1980 N. Runham, pers. comm. N. Runham, pers. comm. Uvalieva, 1978 Randolph, 1973 Voss, 1976; Tuskes, 1981 Daguzan, 1982 Taylor, 1907 Blinn, 1963 Randolph, 1973 Van Cleave & Foster, 1937 Chiu & Chou, 1962 Heatwole & Heatwole, 1978 Solem & Christensen, 1984 Steinberger, pers. comm. Steinberger, pers. comm. Laan, 1971; Pilsbry, 1939 Comfort, 1957 Raboud, 1986 Cook & Cain, 1980 Lazaridou, 1981 Lazaridou, pers. com. Baker, 1968 Lazaridou, pers. com. Staikou & Lazaridou, 1986 Falkner, 1984 pers. observations Chatfield, 1968 pers. observations Heller, 1982; Cowie, 1984 (continued) 288 LONGEVITY IN MOLLUSCS TABLE 3. (continued) Species Lifespan Authority Trichia hispida SL Cameron, 1982 Trochoidea simulata 3 Yom-Tov, 1971 Xeropicta arenosa SL Lazaridou, 1981 Xeropicta vestalis SL Heller & Volokita, 1981 Notes to Table 3: Vaginulus borellianus is an Argentinian slug that lives for about a year to 18 months. Eggs are laid in a mucus envelope on the soil surface (Lanza & Quattrini, 1964; in Runham & Hunter, 1970). Veronicella ameghini is an introduced species in the southern USA. The suggestion that its longevity is “likely around two years” (Dundee, 1977: 114) is a free estimate that is not based upon concrete facts. Achatinella mustelina is a tree-dwelling snail of Hawaii. Ovatella and Melampus dwell in salt marshes along sea coasts. They live above sea level, like land snails, but reproduce by veligers, as marine snails do. | arbitrarily classify them as terrestrial. Ovatella myosotis first develops the masculine system and functions as a male, then also the female system and continues to function as both male and female (Meyer, 1955). Carychium tridentatum is a primitive pulmonate that lives in a saturated atmosphere under fallen leaves and logs. The snails change sex throughout their lifetime: a period of 12 months is required for the completion of a single sperm-producing phase, followed by a single egg-producing one. Morton suggests that the snails appear to have a “double-phase” semelp- arous reproductive strategy. | accept Morton’s semelparous interpretation, but with heavy doubts, as his fig. 2 suggests that at any time of the year there are not nearly enough juveniles in the population to replace the much larger adult group. His data may well suggest that Carychium is an iteroparous, long-lived species with a few juvenile snails joining the population and a few adults dying off each year. Omalonyx felina is a tropical succineid of Venezuela. Punctum pygmaeum is a minute (1.5 mm) snail that has a Holarctic distribution. Its biology in Sweden is currently being studied by B. Baur. Euconulus fulvus and Discus cronkhitei in Canada have, on their shell, “one or more varices which suggests that they survive one or more winters” (Boag & Wishart, 1982: 2636). Aegopinella nitidula has a bienniel life cycle with delayed maturity and overlapping generations, and Mordan (1978) suggests that this may be advantageous in unstable environmental conditions. Limax flavus and L. maximus are generally annual species and hence short-lived (N. Runham, personal communication). Comfort (1957) mentions them as living 5 years (based upon animals studied in captivity), and Godan (1983) suggests that they live three years. Since N. Runham has been personally involved in studying them, | prefer his evidence. Elona quimperiana matures within two years, and lives for another year and a half (Daguzan, 1982). Its classification as a short-lived species stretches the definition of “short-lived” to its limit. Liguus fasciatus is a tree snail of Antillean origin that is found in tropical hardwood trees and exhibits great variability in shell coloration. Voss (1976) suggests that reproduction occurs at the end of the fourth year, after which many snails die, and it should therefore be classified as exhibiting a semelparous strategy. However, the size distributions in his fig. 1-2 suggest an iteroparous cycle, with a few juveniles joining the adult population every year. In addition, his table 1 shows an increase in size of the yearly classes, and this can only be explained by the slow accumulation of individuals into the various size classes over several years, namely an iteroparous strategy, with a very long life-span. Also Tuskes (1981), when studying Liguus fasciatus, reached conclusions differing considerably from those of Voss. Euglandina rosea is a carnivorous snail that feeds mainly upon other land snails. Sphincterochila zonata and S. prophetarum are found in the Negev Desert, where they were studied by Yom-Yov (1971), who suggested that S. zonata lives more than 8 years, and Y. Steinberger (unpublished data), who informs me that they live 15 years at least. Levantina hierosolyma is found in Mediterranean to arid habitats of the Middle East, where it dwells in rock-crevices and beneath stones. Cernuella virgata, a European species, maintains a short life span with an annual life cycle also in populations introduced into Australia (Pomeroy, 1969). Eobania vermiculata in Greece is found at the lower parts of the vegetation. Sexual maturity is reached in two years, and it may then live for another three years (Lazaridou, pers. com,). TABLE 4. Life spans in marine bivalves HELLER 289 Species Nuculidae Acila insignis Nucula annulata Nucula nucleus Nucula sulcata Nucula turgida Nuculanidae Nuculana minuta Nuculana pernula Yoldia limatula Malletiidae Tindaria callistiformis Arcidae Arca boucardi Anadara broughtoni Senilia senilis Glycymeridae Glycymeris yessoensis Mytilidae Bathymodiolous thermophila Brachiodontes variabilis Crenomytilus grayanus Geukensia demissa Modiolus demissus Modiolus modiolus Mytilaster lineatus Mytilus californiensis Mytilus coruscus Mytilus edulis Mytilus galloprovinciallis Mytilus variabilis Perna viridis Septifer keenae Dreisseneidae? Mytilopsis sallei Pinnidae Pinna atropurpura Pteriidae Pinctada martensii Pinctada vulgaris Pectinidae Adamusium colbecki Amusium balloti Amusium japonicum Argopecten gibbus Argopecten irradians Argopecten japonicum Chlamys albidus Chlamys islandica Chlamys opercularis Chlamys varia Notovola meridionalis Patinopecten caurinus Patinopecten yessoensis Pecten maximus Lifespan Authority 9 Zolotarev, 1980 8 Cerrato, 1980 12 Comfort, 1964 174 Comfort, 1964 10 Comfort, 1957 7% Ansell & Parulekar, 1978 9 Zolotarev, 1980 4 Powell & Cummins, 1985 100 Turekian et al., 1975 20 Zolotarev, 1980 46 Zolotarev, 1980 9 Powell & Stanton, 1985 64 Zolotarev, 1980 19 Rhoads et al., 1981 3 Powell & Cummins, 1985 150 Jones, 1983 23 Lutz & Castagna, 1980 8 Zaika, 1973 61 Zolotarev, 1980 3 Zaika, 1973 5 Cerrato, 1980 39 Zolotarev, 1980 15 Zolotarev, 1980 12 Powell & Stanton, 1985 5 Comfort, 1957 В Lee, 1985 15 Zolotarev, 1980 Sie Morton, 1981 12 Butler & Brewster, 1979 8 Powell & Cummins, 1985 7 Comfort, 1957 10 Ralph & Maxwell, 1977 4 Powell & Cummins, 1985 4 Williams & Dredge, 1981 SL Williams & Dredge, 1981 SL Sastry, 1979 SE Powell & Cummins, 1985 8 Zolotarev, 1980 23 Powell & Cummins, 1985 6 Williams & Dredge, 1981 7 Powell & Cummins, 1985 11 Williams & Dredge, 1981 15 Powell & Cummins, 1985 12 Ventilla, 1982 12 Cerrato, 1980 (continued) 290 LONGEVITY IN MOLLUSCS TABLE 4. (continued) Species Lifespan Authority Placopecten magellanicus 12 Williams & Dredge, 1981 Swiftopecten swifti 15 Zolotarev, 1980 Ostreidae Crassostrea madrasensis 4 Powell & Cummins, 1985 Crassostrea virginica 6 Comfort, 1957 Ostrea edulis 20 Christensen & Dance, 1980 Lucinidae Cavatidens omissa SE Powell & Cummins, 1985 Thyasiridae Thyasira flexuosa SL Lopez-Jamar et al., 1987 Ungulinidae Felaniella usta 9 Zolotarev, 1980 Galeommatidae Lasaea rubra 4 McGrath & O'Foighil, 1986 Montacutidae Mysella bidentata 7 Ockelmann & Muus, 1978 Mysella cuneata 6 Gage, 1968 Mysella planulata 4 Franz, 1972 Carditidae Venericardia crebricostata 58 Zolotarev, 1980 Cardiidae Cardium ciliatum 25 Petersen, 1978 Cardium corbis 16 Powell & Cummins, 1985 Cardium edule 7 Cerrato, 1980 Cardium corbis 10 Cerrato, 1980 Cerastoderma glaucum Y Powell 8 Stanton, 1985 Clinocardium nuttallii 14 Zolotarev, 1980 Keenocardium californiese di Zolotarev, 1980 Serripes groenlandicus 22 Petersen, 1978 Mactridae Mactra sulcataria 12 Zolotarev, 1980 Mulinia lateralis 3 Cerrato, 1980 Rangia cuneata 10 Powell & Cummins, 1985 Spisula sachalinensis 55 Zolotarev, 1980 Spisula solidissima 31 Jones et al., 1978 Spisula voyi 52 Zolotarev, 1980 Tresus capax 16 Powell & Cummins, 1985 Mesodesmatidae Mesodesma ventricosum 9 Comfort, 1957; Powell & Cummins, 1985 Solenidae Solen corneus 5 Powell & Cummins, 1985 Solen krustensterni 12 Zolotarev, 1980 Cultellidae Ensis siliqua 12 Comfort, 1964 Siliqua alta 24 Zolotarev, 1980 Siliqua patula 17 Cerrato, 1980 Tellinidae Cadella lubrica 17 Zolotarev, 1980 Gastrana contabulata 15 Zolotarev, 1980 Macoma balthica 18 Zolotarev, 1980 Macoma calcarea 17 Petersen, 1978 Macoma litoralis 6 Powell & Cummins, 1985 Macoma middendorffi 24 Zolotarev, 1980 Peronidia venulosa Sil Zolotarev, 1980 TABLE 4. (continued) HELLER 291 Species Peronidia zyonoensis Tellina alternata Tellina deltoidalis Tellina tenuis Donacidae Donax denticulatus Donax gouldii Donax incarnatus Donax hanleyanus Donax semistriatus Donax serra Donax sordidus Donax spiculum Donax trunculus Donax tumida Donax variabilis Donax venustus Donax vittatus Psammobidae Gari kazunensis Nuttallia ezonis Nuttallia olivacea Scrobiculariidae Scrobicularia plana Semelidae Abra ovata Cumingia tellinoides Theora fragilis Solecurtidae Tagelus divisus Arcticidae Arctica islandica Vesicomyidae Calyptogena magnifica Veneridae Anomalocardia squamosa Callista brevisiphonata Callista chione Callithaca adamsi Dosinia angulosa Dosinia elegans Dosinia exoleta Dosinia hepatica Dosinia japonica Gemma gemma Katelysia opima Mercenaria mercenaria Mercenaria stimpsoni Protothaca euglypta Protothaca jedoensis Protothaca staminea Tapes phillippinarum Tivela stultorum Venerupis japonica Venerupis pullastra Lifespan Authority 61 Zolotarev, 1980 3 Powell & Cummins, 1985 4 Powell & Cummins, 1985 5 Comfort, 1957 Sie Powell & Cummins, 1985 3 Powell & Cummins, 1985 3 Powell & Cummins, 1985 3 Ansell, 1983 SL Ansell, 1983 SL Ansell, 1983 SE Powell & Cummins, 1985 SIE Powell & Cummins, 1985 3 Ansell, 1983 SL Powell & Cummins, 1985 SL Ansell, 1983 SL Ansell, 1983 7. Ansell, 1983 14 Zolotarev, 1980 40 Zolotarev, 1980 20 Zolotarev, 1980 18 Comfort, 1957 4 Zaika, 1973 4 Comfort, 1957 Sik Powell & Cummins, 1985 3 Powell & Stanton, 1985 220 Jones, 1983 11 Jones, 1983 3 Powell & Stanton, 1985 76 Zolotarev, 1980 40 Powell & Cummins, 1985 29 Zolotarev, 1980 26 Zolotarev, 1980 3 Powell & Cummins, 1985 7. Comfort, 1964 6 Powell & Cummins, 1985 27 Zolotarev, 1980 SE Sellmer, 1967 3 Powell & Cummins, 1985 9 Kennish, 1980 40 Zolotarev, 1980 14 Zolotarev, 1980 5 Zolotarev, 1980 13 Роме! & Cummins, 1985 SE Powell & Cummins, 1985 14 Cerrato, 1980 25 Zolotarev, 1980 9 Cerrato, 1980 (continued) 292 LONGEVITY IN MOLLUSCS TABLE 4. Life spans in marine bivalves Species Lifespan Authority Venus gallina 8 Cerrato, 1980 Venus mercenaria 15 Cerrato, 1980 Venus striatula 10 Guillou & Sauriau, 1985 Myidae Mya arenaria 28 Jones, 1983 Mya japonica 42 Zolotarev, 1980 Mya priapus 15 Zolotarev, 1980 Mya truncata 18 Petersen, 1978 Corbulidae Aniscorbula venusta 8 Zolotarev, 1980 Corbula trigona SL Maslin & Bouvet, 1986 Corbula vicaria 4 Powell & Cummins, 1985 Potamocorbula amurensis 5 Zolotarev, 1980 Hiatellidae Hiatella byssifera 15 Petersen, 1978 Panope generosa 120 Jones, 1983 Teredinidae Bankia gouldi SL Hoagland, 1986 Teredo bartschi SL Hoagland, 1986 Teredo navalis SL Hoagland, 1986 Pandoridae Pandora pulchella 11 Zolotarev, 1980 Laternulidae Laternula elliptica 13 Ralph & Maxwell, 1977 Notes to Table 4: Tindaria callistiformis is a minute (8.6 mm) nuculanacean that lives on the sea bottom, at a depth of 3,800 m (Turekian et al., 1975). Comely 1978 suggests that M. modiolus lives only 35 years. Data for Perna viridis concern a polluted habitat where the mussels suffer precocious mortality due to unnaturally stressfull conditions (Lee, 1985). Mysella bidentata lives in association with the ophuroid Amphiura. In the second year of its life it functions as a male; from three years onwards it is a hermaphrodite. (Ockelmann & Muus, 1978). Mysella cuneata, a bivalve of minute size (up to 3 mm) is a commensal of a sipunculid which occupies discarded shells (Gage, 1968). Mysella planulata, of minute size (4 mm), lives in muddy sands. It is a simultaneous hermaphrodite (Franz, 1972). Lasaea rubra is an intertidal bivalve of minute size (3.2 mm). It is ovoviviparous (McGrath & O'Foighil, 1986). Calyptogena magnifica and Bathymodiolous thermica belong to the hydro-thermal vent fauna of Galapagos. The biology of these species is described by Childress et al., 1987. Donax vittatus has a life-span of 3 years at the soutnern end of its geographical range, but longevity increases at higher latitudes and may reach 7 years in northern populations (Ansell, 1983). Corbula trigona dwells in coastal lagoons in western Africa (Maslin & Bouvet, 1986). Teredo is a highly specialised bivalve adapted for boring into wood. Its average life-span in Miami is about 10 weeks (Nair & Saraswathy, 1971). HELLER 293 TABLE 5. Lifespans of freshwater bivalves EE TE en A eee Species Lifespan Authority Mytilidae Limnoperna fortunei SL Morton, 1977 Unionidae Amblema plicata 16 Comfort, 1957 Anodonta anatina 10 Neguus, 1966 Anodonta californiensis 5 Heard, 1975 Anodonta corpulenta 8 Heard, 1975 Anodonta gibbosa 16 Heard, 1975 Anodonta imbecilis 12 Heard, 1975 Anodonta minima 10 Neguus, 1966 Anodonta peggyae 15 Heard, 1975 Anodonta piscinalis 15 Comfort, 1957 Anodonta woodiana 12 Morton, 1986 Anatontoides subcylindraceus 9 Comfort, 1957 Elliptio complanata 12 Matteson, 1948 Elliptio dilatata 12 Comfort, 1957 Lampsilis anodontoides 8 Comfort, 1957 Lampsilis ovata 19 Comfort, 1957 Lampsilis recta 18 Comfort, 1957 Lampsilis siliquoidea 19 Comfort, 1957 Margaritifera margaritifera 116 Hendelberg, 1960; Smith, 1976; Bauer, 1987 Pleurobema coccineum 12 Comfort, 1957 Pleurobema cordatum 30 Yokley, 1972 Quadrula sp. 50 Comfort, 1957 Trifogonia verrucosa 11 Comfort, 1957 Unio crassus 15 Comfort, 1957 Unio pictorum 15 Neguus, 1966 Unio tumidus 11 Neguus, 1966 Dreissenidae Dreissena polymorpha 5 Morton, 1969 Corbiculidae Corbicula fluminea 4 Morton, 1986 Corbicula cf. fluminalis 10 Morton, 1986 Sphaeriidae Byssanodonta cubensis 3 Mackie & Huggins, 1976 Pisidium amnicum SL Baas, 1979 Pisidium annandalei SIE Morton, 1986 Pisidium casertanum SL Mackie, 1984 Pisidium clarkeanum SE Morton, 1986 Pisidium compressum 3 Meier-Brook, 1970 Pisidium hibernicum 3 Meier-Brook, 1970 Pisidium lilljeborgi 3 Meier-Brook, 1970 Pisidium variabile SL Mackie, 1979 Sphaerium corneum SL Dussart, 1979 Sphaerium fabalis SE Mackie, 1979 Sphaerium occidentale SIE Heard, 1977 Sphaerium rivicola Si Heard, 1977 Sphaerium simile 3 Avolizi, 1976 Sphaerium solidum sE Heard, 1977 Sphaerium striatinum SL Mackie, 1984 Sphaerium transversum SE Gale, 1977 Sphaerium partumeium SL Gale, 1977 Musculium japonicum : SL Heard, 1977 Musculium lacustre SL Morton, 1986 Musculium partumeium SL Mackie, 1984 Musculium securis SL Mackie, 1979 Musculium transversum SL Mackie, 1984 (continued) 294 LONGEVITY IN MOLLUSCS Notes to Table 5: Limnoperna fortunei is an inhabitant of freshwater rivers and streams in China and southeast Asia (Morton, 1977). Margaritifera margaritifera is a slow-growing mussel that takes about 20 years to reach sexual maturity. Within the Sphaeriidae, Heard (1 977) suggests that most Pisidium and Sphaerium inhabit permanent lentic and lotic waters, in contrast to most Musculium that are found in ephemeral habitats. Pisidium clarkeanum is generally iteroparous, but may also be semelparous. It lives for 4-8 months (Morton, 1986). Sphaerium corneum lives for about 4-8 months in Canada, one year in Germany and Russia, but may live 3-4 years in Sweden (Heard, 1977). Sphaerium simile in New York may live up to 4-5 years (Heard, 1977). Sphaerium transversum may reach densities of 10,000/m?. It can complete its life history in less than a month (Gale, 1977). TABLE 6. Lifespans in cephalopods HELLER 295 Species Lifespan Authority NAUTILOIDEA Nautilidae Nautilus pompilus 20 Saunders, 1984 COLEOIDEA. Spirulidae Spirula spirula SL Comfort, 1957 Sepiidae Sepia officinalis SL Boletzky, 1983a Sepiolidae Euprymna scolopes SL Singley, 1983 Rossia pacifica SL Anderson, 1987 Sepietta oweniana SL Bergstrom & Summers, 1983 Sepiola robusta SL Boletzky, 1983b Loliginidae Loligo forbesi SL Holme, 1974 Loligo opalescens SL Hixon, 1983 Loligo pealei SL Summers, 1983 Loligo vulgaris SL Worms, 1983 Sepioteuthis sepiola SL Moynihan & Rodaniche, 1983 Gonatidae Gonatus fabricii Sl Kristensen, 1983 Ommastrephidae Dosidicus gigas SL Nesis, 1983 Шех illecebrosus SL О’Оог, 1983 Tadarodes pacificus SL Okutani, 1983 Cranchiidae Teuthowenia megalops SL Nixon, 1983 Octopodidae Bathypolypus arcticus SL O'Dor & Macalaster, 1983 Eledone cirrhosa SL Boyle, 1983 Eledone moschata SL Mangold, 1983b Octopus briareus SL Hanlon, 1983a Octopus cyanea SL Van Heukelem, 1983a Octopus dofleini SL Hartwick, 1983a Octopus joubini SL Hanlon, 1983b Octopus maya SL Van Heukelem, 1983b Octopus tetricus SE Joll, 1983 Octopus vulgaris SE Mangold, 1983 — р реш _ __—_-—_—_— Notes to Table 6: Octopus dofleini is one of the largest octopod species, with an arm span of up to 9.6 m and a weight of 272 kg (Hochberg & Fields, 1980, as cited in Boyle, 1987, table 16.1). Ittakes 2-3 years to reach maximum size. Both males and females stop eating and die after the reproductive period, but males may perhaps live 1 or 2 years longer if they don't reproduce (Hartwick, 1983). Bathypolypus arcticus is a deep sea octopus that lives at depths of 1000 m, in temperatures that rarely range above 6°C. It requires nearly 4 years to complete its life cycle: one year of embryonic development, one of growth, one of gametoge- nesis and one of brooding (O'Dor & Macalaster, 1983). MALACOLOGIA, 1990, 31(2): 297-312 COMPARATIVE MORPHOLOGY OF LIVING NAUTILUS (CEPHALOPODA) FROM THE PHILIPPINES, FIJI AND PALAU Kazushige Tanabe', Jyunzo Tsukahara? & Shozo Hayasaka® ABSTRACT Morphological features of Nautilus from the Philippines, Fiji and Palau are compared from a taxonomic viewpoint on the basis of live-caught animals. In spite of their widely separated distributions, animals from the three populations share quite similar overall shell morphology, ontogenetic shell variation, and radular and jaw structures. Shell coloration and sculpture, and the shape of radular teeth, all of which have been used in previous taxonomic studies, are also markedly variable even in specimens of individual populations, and their ranges of variation overlap among the three samples. The three samples can be distinguished mainly by adult features, such as the dimensions of the shells and total number of septa, which are probably attributed to the difference in their pre-reproductive ages. Judging from these observations and available genetic data, it is suggested that the Palau population, previously distinguished as N. belauensis and the other two populations belong to the same, wide ranging species, N. рот- pilius, or otherwise they are closely related sibling species, N. belauensis and N. pompilius respectively. Key words: Nautilus pompilius, Nautilus belauensis, southwest Pacific, morphology, taxon- omy. INTRODUCTION The superfamily Nautilaceae (Ceph- alopoda, Nautiloidea) first appeared in the Tri- assic, and flourished mainly during the Meso- zoic and Middle Tertiary. They suddenly declined after the Miocene, and at the present time only a few species of the genus Nautilus survive, in the relatively deep waters of the tropical southwestern Pacific. Although 11 species and seven variants of Nautilus have hitherto been proposed (see Saunders, 1987, table 1), their taxonomic va- lidity has long been obscured because of the seemingly morphological conservatism of the genus, extreme splitting of phenotypes based on small collections, and the lack of knowl- edge of the morphological and genetic varia- tion within individual populations. Recently, Saunders (1987) revised these “species” and variants into five or possibly six recognized species (Nautilus pompilius Linnaeus, 1758; N. macromphalus Sowerby, 1849; N. scrobic- ulatus [Lightfoot, 1786]; N. stenomphalus Sowerby, 1849; N. belauensis Saunders, 1981; and possibly N. repertus Iredale, 1944), but some malacologists (e.g. Habe, 1980; Ab- ‘Geological Institute, University of Tokyo, Tokyo 113, Japan. bott & Dance, 1983) regard the latter three species as geographic variants of N. pompil- ius. The species-level taxonomy of Nautilus should, therefore, be re-examined in view of recent biometric and electrophoretic analyses of large live-caught collections (Ward et al., 1977; Tanabe et al., 1983, 1985; Saunders & Davis, 1985; Tanabe & Tsukahara, 1987; Ma- suda & Shinomiya, 1983; Woodruff et al., 1983, 1987; Swan & Saunders, 1987), for these works detected marked morphological and genetic variation even within individual populations. This paper considers the taxonomic rela- tionships of two closely allied morphospecies, N. belauensis and N. pompilius, on the basis of the comparative morphologic examination of large collections from several populations. MATERIAL AND METHODS Material The following three samples of Nautilus populations from widely separated areas were used in this study: (1) 34 specimens (10 “Institute of Biology, Faculty of Science, Kagoshima University, Kagoshima 890, Japan. ®Institute of Earth Sciences, Faculty of Science, Kagoshima University, Kagoshima 890, Japan. 298 TANABE, TSUKAHARA & HAYASAKA males and 24 females) of N. pompilius cap- tured with baited traps from off Bindoy Village (depth of 120-310 m), Tanon Strait, the Phil- ippines, in September 1981 (specimens B1- B32, B41 and B52 among 52 animals listed in Hayasaka et al., 1982, table 10); (2) A total of 280 specimens (245 males, 34 females and one unsexed juvenile) of N. pompilius cap- tured alive from off Suva (Kandavu Passage; depth of 290-450 m), Viti Lebu, Fiji, on two occasions (August-September 1983 and 1986; see Tanabe, 1985, fig. 5, tables 1-3, and Tanabe, 1988, fig. 3, tables 1—4, for their locations and biological data), and (3) 94 specimens (57 males, 36 females and one unsexed juvenile) of N. belauensis captured live from eastern Mutremdiu Bay (= Mutrem- diu Point of Saunders, 1981a, figure 1); depth of 190-400 m, off Augulpelu Reef, Palau, in August-September 1988 and in January 1989. In addition to the above three live- caught samples, two specimens caught from off Siquijor Island, Bohol Strait, the Philip- pines (provided by the courtesy of native fish- ermen; sp. nos. SQ 1-2 in Hayasaka et al., 1982) were used for comparison of ontoge- netic septal growth and mature shell size. The specimens illustrated are kept at the University Museum, University of Tokyo (UMUT), and the remaining ones used for measurements are deposited at the Geology and Biology Institutes, Kagoshima University. Of three (Habe, 1980) or possibly six (Saun- ders, 1987) currently recognized Nautilus species, N. pompilius has the widest geo- graphic range, extending from the Philippines in the northwest to American Samoa in the southeast (Saunders, 1987). The two sam- ples from the Philippines (Tanon Strait) and Fiji thus represent the western and eastern marginal populations of this species. The two specimens from Bohol Strait (Philippines) are compared with the morphotype distinguished as N. pompilius suluensis by Habe & Okutani (1988, figs. 1-4). N. belauensis is known only from Palauan waters, about 800 km from the range of N. pompilius. Methods Following the methods described in Tan- abe & Tsukahara (1987), all animals captured were weighed, sexed, and measured (see Hayasaka et al., 1982, table 10, and the re- vised version in Tanabe et al., 1983, table 1; Tanabe, 1988, table 3; Tanabe & Tsukahara, 1989, table 2). Some were tagged and re- leased near the sampling locations for long- term growth analysis, and most of the remain- ing animals were dissected, and their fresh soft tissues and gonads were weighed by means of a dial scale (accuracy + 10 mg) for biometry. In addition, the buccal mass was removed from the body of selected speci- mens. It was soaked in a 20% KOH solution for 20 minutes, and thereafter the mandible and radular ribbon were carefully removed. The radular and jaw morphologies of each specimen were observed under the optical and scanning electron microscopes. We further analyzed the ontogenetic shell growth patterns in several specimens se- lected from each sample. For this purpose, radius vector (А), breadth (В), height (H) and flank length (F) of a whorl, and half length of umbilicus (C), disregarding secondary umbil- ical deposits (callus), which were measured in each dorso-ventrally sectioned shell at inter- vals of 180° using a profile projector (NIKON, V16), attached to a digital micrometer (accu- racy + 1 pm) (magnification x 20; see Tan- abe & Tsukahara, 1987, figure 1, for mea- surements). Based on these measurements, four geometric parameters; i.e. whorl expan- sion rate [(R,/R,,_,)*; п >1m], flank position (F/D), whorl inflation (B/H) and involution (C/ R) at different growth stages were calculated for each specimen. SHELL MORPHOLOGY Gross Morphology and Coloration The shells of the Palau, Philippine (Tanon) and Fiji Nautilus essentially resemble one an- other in overall morphology and shell colora- ‚ tion. Their whorls are tightly coiled with a nar- row umbilicus, mostly filled with a callus in the middle-late growth stages. The shell colora- tion consists of two elements, i.e. irregular reddish brown to brown serrate radial stripes extending from the inner flank to venter and branching across the mid-flank, and a longi- tudinal stripe of the same color around the umbilical area (Fig. 1). In mature and almost mature shells, the former element tends to disappear toward the aperture, retaining only its trace on the inner flank. The mode of dis- tribution, strength and hue of the shell color- ation is fairly variable even in the specimens from the same area, but the Fiji sample con- sists mostly of the phenotype with relatively short and broad radial stripes (Fig. 1). COMPARATIVE MORPHOLOGY OF NAUTILUS 299 Rn FIG. 1. Mature shells of Nautilus belauensis (A-B) and Nautilus pompilius (C-G), showing the similarity in overall morphology and coloration. А-В. Male (A: T3-2; UMUT RM 18708-3) and female (B: T9-3; UMUT RM 18708-9) from Palau. C-D. Male (C: B21; UMUT RM 18705-3) and female (B30; UMUT RM 18705-7) from Tanon Strait, the Philippines. E-F. Male (E: SV6-1; UMUT RM 18707-2) and female (F: SV5-3; UMUT RM 18707-1) from off Suva, Viti Lebu Island, Fiji. G. Sex-unknown specimen (SQ3; UMUT RM 18706-2) from Bohol Strait near Siquijor Island, the Philippines. Scale bar represents 5 cm. 300 TANABE, TSUKAHARA & HAYASAKA FIG. 2. Optical micrographs of the ventral shell surface of Nautilus belauensis (A) and Nautilus pompilius (B-D), showing longitudinally crenulated sculpture. A. UMUT RM 18708-2 (T2-4; female) from Palau. B. UMUT RM 18707-7 (SV13-8; female) from Fiji. C. UMUT RM 18707-8 (SV13-13; male) from Fiji. D. UMUT RM 18705-8 (B31; female) from the Philippines (Tanon Strait). Scale bars indicate 500 um. The whorls of every specimen exhibit dense sinuous growth lines. In addition, well- marked, longitudinally crenulated ridges showing a reticulate pattern are developed in every specimen from Palau. This sculpture was assigned by Saunders (1981a) as one of the diagnoses for distinguishing the Palauan N. belauensis from N. pompilius. However, it also occurs on the ventral side of many spec- imens of N. pompilius from Fiji and the Phil- ippines, although it is especially conspicuous in the Palau specimens (Fig. 2). Ontogenetic Shell Variation Biometric analysis of selected specimens in dorso-ventral section reveals that the three samples exhibit similar ontogenetic patterns of shell geometric parameters, as repre- sented by the gradual decrease of whorl in- flation (B/H) with increase of whorl number, sudden decline of flank position (F/D) near the end of the first whorl, and abrupt increase and subsequent decline of distance of the whorls to the coiling axis (C/R) in the second- third whorls (Fig. 3). In every sample, the ranges of variation of geometric parameters are larger in the early stage than in the later stage. The observed ranges of each param- eter at a given whorl stage in Fiji and Palau specimens mostly overlap each other, except for the larger C/R ratio in the later stage of the Palau specimens. The umbilicus of every specimen is initially free from a callus. The callus begins to appear during the develop- ment of the second whorl, increasing its thick- COMPARATIVE MORPHOLOGY OF AAUTILUS 301 07 @ Palau (N=7) oFiji (N=21) * Philippines(N=4) 03 ОБ 25 3545 55 657 25 3.5 4.5 55 65x 05 05115 25 35 45 55 651 = 15 25 35 45 55 657 TOTAL ROTATION ANGLE FIG. 3. Ontogenetic changes of whorl expansion rate [((R,/R,,_+)*], frank position (F/D), whorl inflation rate (B/H), and whorl involution rate (C/R) versus total rotation angle of spiral for specimens of Nautilus belauen- sis from Palau and Nautilus pompilius from the Philippines (Tañon Strait) and Fiji. Vertical bars indicate the range of one standard deviation. ness as the shell grows (Fig. 4). A complete ing the formation of the second whorl for the seal ofthe umbilicus by the callus occurs dur- Fiji and Philippine specimens, while it is de- 302 TANABE, TSUKAHARA & HAYASAKA u — © | | Be. ww = == 10mm ET FIG. 4. Drawings of cross-sectioned specimens of Nautilus belauensis from Palau (A-C) and Nautilus pompilius from the Philippines (Tañon Strait) (D-F) and Fiji (G-H). A. UMUT RM 18708-7 (T9-1, ma- ture male), В. UMUT RM 18708-8 (T9-2, mature male), C. UMUT RM 18708-2 (T2-4, mature female), D. UMUT RM 18705-5 (B27, mature male), Е. UMUT RM 18705-6 (B29, mature male), F. UMUT RM 18705-4 (B22, submature female), G. UMUT RM 18707-3 (SV12-1, submature female), H. UMUT RM 18707-5 (SV13-1, submature male). b.c.: body chamber, c: callus. layed after the formation of the second whorl for the Palau specimens. This observation correlates well with the description of Saun- ders (1987, pp. 43—44). The scatter plot of B/H ratios of all captured animals exhibits wide ranging intra- and inter- populational variation of this parameter at least for premature and mature specimens (Fig. 5). Atthe same shell size (D = 150-160 mm) most Fiji specimens have a more com- pressed shell than the Philippine specimens. The Palau specimens display remarkably wide variation in B/H ratio both in the imma- ture and mature stages, and the values of immature and submature specimens partly overlap those of mature specimens from Fiji and the Philippines. The ontogenetic pattern of chamber length (= distance between contiguous septa) in the early to middle stages is fairly alike among specimens of the three samples and the one Siquijor specimen (Fig. 6). Variation of Mature Shells As demonstrated by previous authors (Haven, 1977; Ward et al., 1977; Saunders & Spinosa, 1978; Ward & Martin, 1980; Ha- yasaka et al., 1982, 1987; Tanabe et al., 1983; Tanabe & Tsukahara, 1987), species of living Nautilus show distinct sexual dimor- phism in the size and weight of animals and shell proportions at maturity. Namely, mature males are generally larger and possess broader shells than mature females. By examining the gonad development in live-caught animals, Tanabe & Tsukahara (1987) discussed the sexual dimorphism in N. pompilius from the Philippines (Tanon Strait) and Fiji. The difference in shell size at maturity among the Palau, Fiji and Philippine (Tanon) populations is made clear by summarizing the gonad and tissue weight data on live-caught animals (Tsukahara, 1985; Tanabe & Tsuka- hara, 1987) (Fig. 7). In each sample, abrupt increase of gonad weight initiates at the same shell size for both sexes. Full development of the gonad is well marked in the male speci- mens from Palau and Fiji, and this causes the relatively larger shell size in males than in fe- males at the same gonad index [= gonad weight/tissue weight (%)] (Fig. 7). Figure 7 also shows the difference in shell diameter at maturity among the three sam- ples. The average diameters of male and fe- ‘male specimens in the Palau sample (ca. 210 mm and 190 mm respectively) are much larger than those in the Fiji sample (ca. 150 mm and 140 mm, respectively). Those in the Philippine (Tanon) sample (ca. 170 mm and 160 mm; see also Tanabe et al., 1983, table 3) are intermediate between the Fiji and Palau samples. Thus, the above differences in mature shell size among the three samples are much larger than that between sexes within the same sample. Recognition of maturity is also shown by such characteristic shell features as approxi- mation of the final two or three septa, a thick- ened last septum, and blackened and thick- ened aperture (e.g. Stenzel, 1964; Collins & COMPARATIVE MORPHOLOGY OF NAUTILUS 303 1.0 о © BREADTH / HEIGHT о © о = 0.6 100 150 = PALAU (N=94) A PHILIPPINES (N=34) e FIJI (N=179) 200 250 SHELL DIAMETER (mm) FIG. 5. Scatter plot of shell breadth/height ratio (B/H) versus shell diameter for specimens of Nautilus belauensis from Palau and Nautilus pompilius from the Philippines (Tañon Strait) and Fiji. Measurements of 179 animals captured in 1986 (Tanabe, 1987, table 3) are used for the Fiji sample. Ward, 1987), because these features com- monly occur in specimens with a large gonad index. In accordance with these criteria, the two specimens from Bohol Strait near Siquijor Island (the Philippines) are regarded as ma- ture or submature shells. They are much smaller in shell diameter (ca. 130 mm; Fig. 1G) than the mature specimens from Tañon Strait. Total number of septa at maturity ap- pears to be different among the three sam- ples (33-39, 32-35, and 28-32 septa in the Palau, Philippine (Tañon) and Fiji samples re- spectively) (Fig. 8). RADULAR AND JAW MORPHOLOGIES Radula The radula of Nautilus is secreted by colum- nar epithelial cells, named odontoblasts, in the posterior part of the radular sac, and is generated anteriorly in a series of rows (Tanabe & Fukuda, 1987). Each row consists of nine primary teeth (one central rachidian, and two pairs of laterals and marginals on each side) and two pairs of marginal support plates (Thiele, 1893; Vayssiere, 1896; Griffin, 1900; Naef, 1923; Solem & Richardson, 1975; Lehmann, 1976; Mikami et al., 1980; Saunders, 1981a, 1987; Tanabe & Fukuda, 1987). This arrangement is clearly distin- guished from that in modern coleoids, which in general have seven primary teeth and a pair of marginal plates (Solem & Richardson, 1975). Morphological features of each radular ele- ment are essentially identical among the Phil- ippine (Tañon), Fiji and Palau Nautilus (Figs. 9-10). Namely, the central rachidian tooth is triangular in shape, being more than two or three times as high as the two laterals (Fig. 9). The two marginal teeth are much longer than the central and laterals; they are gently 304 TANABE, TSUKAHARA & HAYASAKA 20 T2-1(male), Palau T5-3(female), Palau B-5(male), Tanon St., Philippines B-3(female), Tanon St., Philippines 15 = SV13-2(male), Зима, Fiji Е > WwW о z < = 10 oO = < = а. WwW [ep] 0 10 SQ-1(sex unknown), Bohol St., Philip. 20 30 40 CHAMBER NUMBER FIG. 6. Ontogenetic change of chamber length (= septal interval) for selected mature specimens of Nautilus belauensis from Palau and Nautilus pompilius from the Philippines (Tañon and Bohol Straits) and Fiji. A. UMUT RM 18708-1, B. UMUT RM 18708-5, C. UMUT RM 18705-2, D. UMUT RM 18705-1, E. UMUT RM 18706-1, F. UMUT RM 18707-6. curved and acutely projected anteriorly, with two strong grooves along their longitudinal axis (Fig. 10). In the anterior portion, the teeth are subcircular in cross section with a round tip, but they become rapidly broaden and compressed toward the base. A characteristic spatula-like anterior expansion is present at the base of the marginal teeth of every spec- imen from Palau and Fiji (Fig. 10A-C 4 E), but this feature is not so prominent in many specimens from the Philippines (Fig. 10D; see also Saunders, 1981a, figure 2). The marginal support plates are rectangular in outline; the inner one is larger than the outer. A marked depression is developed in the an- terior portion of the outer plate. The shape of each radular element is mark- edly variable even in the specimens from the same area, and the range of variation of the height/width ratio of the central tooth in the Palau sample apparently overlaps those in the Fiji and the Philippine samples (Fig. 11). Jaws The jaw apparatus of Nautilus differs from those of modern coleoids by the presence of conspicuous anterior calcareous coverings COMPARATIVE MORPHOLOGY OF NAUTILUS 305 sMale oFemale PALAU ¿Male . PHILIPPINES e Male FlJI o Female GONAD INDEX 100 110 120 130 140 150 160 170 180 190 200 2510 220 230 SHELL DIAMETER (mm) FIG. 7. Scatter plot of gonad index [gonad weight/tissue weight (%)] versus shell diameter for specimens of Nautilus belauensis from Palau and Nautilus pompilius from the Philippines (Tanon Strait) and Fiji. Bi ©№ = 9.) I / Philippines (N=14) / Palau (N=8) Frequency Number of septa FIG. 8. Variation in the total number of septa at maturity for Nautilus belauensis from Palau and Nautilus pompilius from the Philippines (Tanon Strait) and Fiji. on the chitinous plates of the upper and lower jaws and by the shorter inner lamellae of the lower jaw (Okutani & Mikami, 1977; Saunders et al., 1978; Tanabe & Fukuda, 1987). Its overall morphology, composition and struc- tural relationship with the jaw muscles are the same among the species of Nautilus, and are well designed for a cutting and shearing func- tion (Saunders et al., 1978; Tanabe & Fukuda, 1987). The lower jaws of the Fiji and Palau spec- imens are both characterized by a distinct an- terior depression in the antero-dorsal margin of the outer lamella, followed by a rather straight shoulder (Fig. 12A-B & E-F). In con- trast, the lower jaws of the Philippine (Tanon) specimens mostly lack such a depression, and their outer lamella has gently concave antero-dorsal margin and roundly convex shoulder (Fig. 12C—D). DISCUSSION Taxonomic Relationships The present study shows that the Philippine (Tanon Strait), Fiji and Palau Nautilus popu- lations have strong affinities in overall shell morphology and radular and jaw structures. Furthermore, the large collections from the populations display similar ontogenetic pat- terns for the shell shape parameters and chamber length, and they can be distin- 306 TANABE, TSUKAHARA & HAYASAKA FIG. 9. Scanning electron micrographs of central rachidian and lateral (in part) radular teeth in Nautilus belauensis from Palau (A-B) and Nautilus pompilius from the Philippines (Tanon Strait) (C-D) and Fiji (E-F). A. UMUT RM 18708-6 (T5-4, mature female), B. UMUT RM 18708-8 (T9-2, mature male), C. UMUT RM 18705-7 (B30; mature female), D. ОМУТ RM 18705-5 (B27; mature male), Е. UMUT RM 18707-4 (SV12-3; immature female), F. UMUT RM 18707-9 (SV13-14; immature female). Scale bars indicate 200 um. COMPARATIVE MORPHOLOGY OF NAUTILUS 307 FIG. 10. Scanning electron micrographs of overall radula (A) and its marginal element (B-E) for specimens of Nautilus pompilius from Fiji (A-B) and the Philippines (Tanon Strait) (C-D), and Nautilus belauensis from Palau (E). A-B. UMUT RM 18707-4 (SV12-3), C. UMUT RM 18705-5 (B27), D. UMUT RM 18705-7 (B30), Е. UMUT RM 18708-6 (T5-4). Scale bars indicate 500 ит. Anatomy. с: central rachidian tooth, L, and L,: inner and outer lateral tooth, M, and M.: inner and outer marginal tooth, MP, and MP: inner and outer marginal support plates. guished mainly by the dimensions of adult an- imals, such as the total live weight, shell size, and total number of septa. These observa- tions may offer serious problems in recogniz- ing the Palauan population as a separate spe- cies. The Palauan Nautilus was identified by Dugdale & Faulkner (1976) as Nautilus sp. It was subsequently identified as N. pompilius (Faulkner, 1976; Saunders & Ward, 1979; Carlson, 1979) or N. cf. pompilius (Saunders et al., 1978; Saunders & Spinosa, 1978, 1979). Later, Saunders (1981a) proposed a new species, N. belauensis, on the basis of 308 TANABE, TSUKAHARA & HAYASAKA 1.57 ja, "PALAU CS) 2 H/W= 2.0 о of (2) y a PHILIPPINES (4) ЗЕ 2 = (2) eFiyi (4) E о » (2) Pa = 12 + y = H/W-=15 | / ME о я | о - о Е ] о ) = = / gef + | o - ] А т 09 | A о — | a w os} A E AE J H/W = 1.0 e 07+ a 7 o / o /e / / e | 06 + / e Y ff TL / 05 | f . / / 04 + } e 03 и и IP. 1 1 1 1 J 01 02 03 04 05 06 07 08 BASAL WIDTH (mm) FIG. 11. Scatter plot of central rachidian tooth height (H) and basal width (W) for specimens of Nautilus belauensis from Palau and Nautilus pom- pilius from the Philippines (Tanon Strait) and Fiji. examination of more than 1,000 live caught animals. According to Saunders (1981a, b, 1987), N. belauensis is distinguished from N. pompilius by its larger mature size and wider central rachidian radular tooth, and by the presence of longitudinally crenulated growth lines on the shell. The present work, however, confirms the presence of crenulated shell or- namentation in many specimens of N. pom- pilius from Fiji and the Philippines. Further- more, the width/height ratios of radular elements are highly variable even in the spec- imens from the same area, suggesting that the shape of radular teeth appears to be of little significance at least for the species-level systematics of living Nautilus. The remaining diagnosis of the Palau population, unusually large mature shell size, should not be relied on for distinguishing species for the following reasons. Indeed, the widespread species, N. pompilius displays well-marked morphologi- cal differentiation regarding overall weight and size at maturity, proportion and coloration of shells, and the trends of the allometric re- lationships of several characters of the shells and soft tissues, not only among the geo- graphically separated populations (Ward et al., 1977; Hayasaka et al., 1982, 1987; Tan- abe & Tsukahara, 1987; Saunders, 1987; К. Tanabe's observations on specimens from various localities housed in the U.S. National Museum of Natural History), but also among neighboring populations (Hayasaka et al., 1982; Saunders, 1987; Swan & Saunders, 1987; Habe & Okutani, 1988). The minor dif- ference in the lower jaw morphology between the Philippine and Fiji specimens can proba- bly be attributed to conspecific variation. In addition to the above results at morpho- logical level, recent examinations of large col- lections using electropheretic techniques pro- vided interesting data relevant to taxonomic relationships of Nautilus populations from a genetic viewpoint (Masuda & Shinomiya, 1983; Woodruff et al., 1983, 1987). These works have made clear that Nautilus exhibits normal or slightly high levels of genetic vari- ation and that the isolated populations are well differentiated genetically. Relying upon Nei’s (1978) genetic distance coefficients, Woodruff et al. (1987) suggested that the Palau population (N. belauensis) and possibly the Fiji population (N. pompilius) are closely related to, but well differentiated at a species level from the populations of N. pompilius in the waters around New Guinea and Queen- sland. The genetic distance coefficients be- tween the samples of N. belauensis from Palau and N. pompilius from eight localities in the southwestern Pacific excluding the Philip- pines (< 0.2) are, however, much smaller than those between paired samples of N. scrobiculatus, N. macromphalus and N. pom- pilius (> 0.5) (see Woodruff et al., 1987, table IV & fig. 2). As Woodruff et al. (1987) docu- mented, there is no simple basis to translate a genetic distance into a taxonomic decision, because the processes of speciation are not closely coupled to the changes of structural genes. To sum up the above-mentioned mor- phological and genetic data, two different in- terpretations can be considered for the taxo- nomic relationship among the three populations. The one is that the populations in the Philippine, Fiji and Palauan waters are summarized into the amphimictically out- breeding species, N. pompilius, with high lev- els of genetic and morphological differentia- tion, and the other is that N. belauensis is a distinct species reproductively isolated from COMPARATIVE MORPHOLOGY OF NAUTILUS 309 FIG. 12. Drawings of upper (right side) and lower (left side) jaws for specimens of Nautilus pompilius from Fiji (A-B) and the Philippines (Tanon Strait) (C-D), and Nautilus belauensis from Palau (E-F) (lateral views). A. UMUT RM 18707-9 (SV13-14; mature female), В. UMUT RM 18707-10 (SV28-4-2; mature male), С. UMUT RM 18705-7 (B30; mature female), D. UMUT RM 18705-2 (B5, mature male), E. UMUT RM 18708-5 (T5-3; mature female), Е. UMUT RM 18708-4 (T5-1; mature male). Scale Багз indicate 1 cm. the populations of N. pompilius. In this paper, we refrain from choosing between the two be- cause of the insufficient data for the genetic variation of N. pompilius throughout its wide geographic range, especially of the popula- tions in the Philippine waters. Interpretation on Mature Shell Size Variation In his discussion of Nautilus systematics, Saunders (1987) suggested that the differ- ence in mature shell size between N. belauen- sis and N. pompilius does not result from the difference in the period of growth, on the basis of counting of septal number and the stage of the umbilical callus appearance. Although the absolute growth and longevity of Nautilus in their natural habitats are not fully understood, previous direct and indirect growth rate mea- surements by release-recapture experiments of tagged specimens, radiographic observa- tion of aquarium specimens, and radiometric dating of septa have shown that the period of chamber (septal) formation increases ехро- nentially with increasing chamber number (Cochran et al., 1981; Saunders, 1983, 1984; Ward, 1985; Cochran & Landman, 1984; see compilation in Landman & Cochran, 1987, fig- ure 4, table V). The marked difference in the total number of septa among the mature spec- imens from Fiji, the Philippines and Palau can be, therefore, interpreted as reflecting the dif- ference in the pre-reproductive age among them. This interpretation is in accord with Landman & Cochran's (1987) age estimate from septal growth equations (10.9 y and 5.9 y for N. belauensis and N. pompilius respec- tively). The Palau population may attain sexual maturity at slower rates than the Fiji and Phil- ippine populations, although its rate of septal formation in earlier stages may not differ greatly from those in the Philippine and Fiji populations. The rate of shell growth and the time required to attain sexual maturity may be controlled by both ecology (food supply, tem- perature, water depth etc.) and genetic fac- tors, and the degrees of dependence of these factors on growth apparently differ among in- dividual populations. Based on the data from genetic analysis, Woodruff et al. (1987) sug- gested that the Palau and Fiji populations have distinctly diverged from the ancestral form of 310 TANABE, TSUKAHARA & HAYASAKA N. pompilius by peripheral isolation for about 1 million years. We have no available data on the fossil record of Nautilus to verify this hy- pothesis, but if it is correct, the adult size in- crease or decrease in relation to the length of pre-reproductive age in the history of N. pom- pilius stock can be expressed by hypermor- phosis and progenesis in terms of McNama- ra's (1986) definition of heterochrony. Conclusion The Nautilus populations in Palau, the Phil- ippines and Fiji are essentially similar in over- all shell morphology, ontogenetic shell varia- tion, and jaw and radular structures. They are distinguished mainly by the dimensions of adult animals. From these morphological ev- idence and the available genetic data, the Palau and the other two populations are re- garded as either summarizing into the wide- spread species, Nautilus pompilius, or be- longing to the closely related sibling species, N. belauensis and N. pompilius respectively. The size difference among the adult animals from the three populations probably results from the difference in their pre-reproductive ages. ACKNOWLEDGMENTS We acknowledge Yoshiko Kakinuma for her facilities and encouragement, both in the field and laboratory. Our thanks to Angel C. Alcala, Uday Raj, and David K. Idip for providing fa- cilities to operate our field research, other members of the project in the Philippines, Fiji and Palau for their assistance in collecting live Nautilus and for helpful discussions, and Clyde F. Roper for allowing one of us (K. T.) to observe the collections of Nautilus at the U. S. National Museum of Natural History in his care. W. Bruce Saunders and Neil H. Land- man read the manuscript critically and gave useful comments for improvement of this pa- per. 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In: SAUNDERS, Revised Ms. accepted 19 October 1989 MALACOLOGIA, 1990, 31(2): 313-326 CROSS SECTIONAL MORPHOLOGY OF THE GLADIUS IN THE FAMILY OMMASTREPHIDAE (CEPHALOPODA: TEUTHOIDEA) AND ITS BEARING ON INTRAFAMILIAL SYSTEMATICS Ronald B. Toll Department of Biology, The University of the South, Sewanee, Tennessee, U.S.A. 37375 ABSTRACT The cross sectional morphology of the ommastrephid gladius is compared among 15 species in 11 genera of the three currently recognized subfamilies. The three axıal complexes of the free rachis are shown to comprise a suite of characters of systematic importance. Intrafamilial rela- tionships derived from characters of the gladius generally conform to the traditional classification of the family based on a synthesis of traditional characters, with the exception of subfamilial organization. The depositional layering of chitin which occurs as part of the accretive growth of the gladius is easily seen in cross section using either light or scanning electron microscopy. Examination of these layers can provide information on ontogenetic changes in gladius con- struction because the early morphology is covered but apparently not altered during subsequent depositional events. Key words: Teuthoidea, Oegopsida, Ommastrephidae, gladius morphology, phylogeny, shell, squid. INTRODUCTION Squids of the family Ommastrephidae are robust, muscular, powerful swimmers. Adults range in size from about 8.0 cm (Hyaloteuthis pelagica) to over 1.0 m (Dosidicus gigas) in mantle length (Wormuth, 1976; Nesis, 1983). The majority of taxa are open ocean epipe- lagic animals while some (e.g. Шех and To- darodes) range over continental shelves. The ommastrephids are predaceous carnivores that feed primarily on finfishes and other squids. They are prey to many predator spe- cies including marine mammals and finfishes. Many ommastrephids are commercially ex- ploited for both human consumption and for bait in finfish fisheries and as such form the basis of substantial fisheries in many areas of the world (Clarke, 1966; Roper, 1983; Rath- jen & Voss, 1987). Roper (1983) included the Ommastre- phidae as one of the four families of cephalo- pods (along with the Sepiidae, Octopodidae, and Loliginidae) most critically in need of comprehensive systematic revision based on four criteria. The groups are: (1) speciose and occur in greatest abundance in shallow wa- ters; (2) support major fisheries; (3) support biomedical, ecological and other biological re- search; (4) poorly known systematically. Prior to and as a result of Roper’s (1983) listing of 313 these four groups, the systematics of the Om- mastrephidae represents an area of consid- erable recent research (e.g. Roper, et al., 1969; Adam, 1975; Zuev et al., 1975; Wor- muth, 1976; Nesis, 1978, 1983; Lu & Dun- ning, 1982; Roeleveld, 1982, 1988; O'Dor, 1983; Okutani, 1983). A variety of morpholog- ical and meristic characters have been used in the systematic study of ommastrephids. Traditionally, the three subfamilies, Ommas- trephinae, Todarodinae, and Illicinae, have been separated on characters associated with the funnel groove, specifically the occur- rence of side pockets and foveolae. Below the subfamilial level, characters used to delineate taxa include fin angle, club sucker arrange- ment and dentition, spermatophore morphol- ogy, arm protective membrane development, condition of the funnel-mantle locking carti- lages, type and distribution of light organs, hectocotylus morphology, and various mor- phometric relationships of the arms, tenta- cles, clubs, fins, etc. Details of the gladius or pen have been absent from the descriptions and systematic analyses of most of the recent systematic contributions to the Ommas- trephidae. In contrast, in many of the older contributions to ommastrephid systematics (e.g. Pfeffer, 1912; Sasaki, 1929) the gladius is described, sometimes in great detail, and often illustrated. Collectively, these reports, in 314 TOLL particular Pfeffer's (1912) monumental mono- graph of the Oegopsida, which contains de- tailed illustrations of the gladius of many ommastrephid taxa, suggest that the om- mastrephid gladius is a highly conservative structure, exhibiting little morphologic varia- tion across the family, with the exception of relatively minor differences in the width of the free rachis and the length of the cone field. An exception to this perceived homogeneity among ommastrephid gladii is the unique, layered deposit of chitin within the concavity of the cone field of Dosidicus gigas (Steen- strup, 1857; Pfeffer, 1912; Toll, 1982). The existence of the widely held assumption that the ommastrephid gladius is of little value to systematic study is probably the cause of the relative lack of interest in this structure as re- flected by more recent systematic contribu- tions to this group. Indeed, the descriptive ac- counts of two recently described species lack any mention of the gladius whatsoever (Orni- thoteuthis antillarum Adam, 1957; Todaropsis filippovae Adam, 1975). The examination of cross sections of the ommastrephid gladius is not new. Lesueur (1821), Ball (1841), Posselt (1890), Verrill (1882), Naef (1923), Sasaki (1929), and Ran- curel (1970) included variously detailed men- tion of the cross sectional shapes of the gla- dius or described the characteristics of the axes along the free rachis allowing inferences of cross sections to be made. Indeed, Naef (1923) used aspects of the cross sectional structure of the gladius as part of species di- agnoses. Toll (1982) demonstrated that cross sections of ommastrephid gladii contained hitherto unknown systematic characters that could be useful in phylogenetic reconstruc- tions. The same characters could be valuable in identifying fragmentary ommastrephid re- mains encountered in stomach contents of predators. This paper presents the results of a comparative study of ommastrephid gladius cross sections. The results show that while the gross shape of the ommastrephid gladius is similar throughout the family, there is con- sistent variation in cross sectional shape. This variation should be assessed as part of future studies regarding ommastrephid systematics. Finally, overall shape and structure of the gla- dius are two of the few anatomical characters of squids that allow direct comparison be- tween fossil and Recent teuthoids and could prove useful in establishing phylogenetic re- lationships to fossil ommastrephid antece- dents (see Donovan & Toll, 1988). MATERIALS AND METHODS Gladii were dissected out of preserved specimens by means of a longitudinal incision along the ventral midline. The cut edges of the mantle wall were reflected back to expose the viscera. The left gill was severed from its attachment to the inner surface of the mantle musculature. Beginning anteriorly and pro- gressing posteriorly, the visceral mass was freed from the mantle wall along its left side and reflected to the right exposing the glad- ius, still in the shell sac, below it. Once com- pletely exposed, the shell sac was cut open ventrally and laterally to allow the gladius to be removed from the inner surface of the dor- sal mantle musculature. As necessary, the nuchal muscles, which extend from the nuchal cartilage to the ventral surface of the anterior free rachis, were severed from their insertion on the shell sac. The narrowest part of the gladius, that area at the posterior limit of the free rachis, is sometimes completely buried in the mantle musculature and further dissection is required to free it. Also, in some taxa, the musculature of the tail region must be opened in order to free the apex of the conus. The procedure for extraction of the gladius described here is preferable to exci- sion of the gladius via dissection through the dorsal mantle musculature. When carefully executed, the ventral removal method results in little substantiative damage to the speci- men. Excised gladii were kept in either 40% isopropyl or 70% ethyl alcohol and stored in separate vials or bottles along with the spec- imen from which it was removed. Because this study represented the first ex- tensive, comparative examination of cross sections of ommastrephid gladii, aconvention ‚ needed to be established regarding the choice and standardization of levels of sec- tion to be examined. Four cross sections were selected and named as follows: level A, level B, level C, and level D. The anterior three levels (A, B, and C) were established at dis- crete proportional distances from the anterior tip of the gladius. These are 0.10 GL (one- tenth of the length of the gladius measured from its anterior tip), 0.25 GL (one-quarter of the length of the gladius measured from its anterior tip), and 0.60 GL (six-tenths of the length of the gladius measured from its ante- rior tip), respectively. Level D coincides with the posterior limit of the free rachis where it meets the cone field. Cross sections were made using a new single edge razor blade OMMASTREPHID GLADIUS MORPHOLOGY 315 with the gladius held firmly on a hard rubber block. The cross sections of different taxa are drawn approximately to the same size to fa- cilitate direct comparisons. All sections are oriented with the dorsal surface toward the top of the page. In each set, level A is at the top and levels B, C, and D are in ordered sequence below. Each set of cross sections is based on near mature or fully mature individ- uals and represents a composite, typical for that species. Variation is discussed along with the treatment of individual taxa and in the General Discussion. Abbreviations used in the text are as fol- lows: M, male; F, female, ML; dorsal mantle length; GL, gladius length; ANSP, Academy of Natural Sciences of Philadelphia; BCF, Bu- reau of Commercial Fisheries (now National Marine Fisheries Service); IATTC, Inter- American Tropical Tuna Commission; MCZ, Museum of Comparative Zoology, Harvard University; UMML, Invertebrate Museum, Rosenstiel School of Marine and Atmospheric Science, University of Miami; USNM, National Museum of Natural History, Smithsonian In- stitution; DISC, R/V DISCOVERER; ELT, USNS ELTANIN; ORE, M/V OREGON; P, R/ VE SOHN ELLIOTT PILLSBURY; TC, R/V TOWNSEND CROMWELL; ET, Engel Trawl; IKMT, Issacs-Kidd midwater trawl; MWT, mid- water trawl; OT, otter trawl. MORPHOLOGY AND ANATOMICAL RELATIONSHIPS OF THE OMMASTREPHID GLADIUS The free rachis (Fig. 1) is long, broadest anteriorly, tapered posteriorly and terminates anteriorly in a stiff point. Anteriorly, there are three axial complexes, one medial and two lateral, each with three primary components; a ventrally displaced axis, a dorsal plate, and a commissure that joins the axis to the plate (Fig. 2). The plates and commissures can vary in thickness and width. Laterally, the plates are rounded or tapered to a point and ventrally recurved. The two lateral plates are connected to the central one by a pair of broad, thin, lateral fields. The lateral axes can be bifurcated anteriorly. The lateral axis, plate, and commissure progressively coa- lesce posteriorly to level C where the lateral axial complex varies from lobate to hook- shaped with an admedial cleft. The three axial complexes (hereafter referred to as the me- dial complex and lateral complexes) converge posteriorly to form a single complex of vari- able shape at level D. This single axis ex- tends to the posterior tip of the gladius. The vanes are reduced to a small, spindle-shaped cone field that accounts for 10% to 25% of the total GL. Fine, radiating striae converge ante- riorly from the anterolateral portions of the cone field toward the rachis. There is a small, conical primary conus. The gladius is partially embedded in the ventral surface of the dorsal mantle muscula- ture along the dorsal midline. In some taxa, the anterolateral edges of the free rachis are over- lain by muscle. In many, the narrow posterior portion of the free rachis, including part or all of the cone field, is completely buried within the mantle musculature. The nuchal muscles insert on the shell sac covering the ventral surface of the medial rachis fields posterior to the widest part of the free rachis. The insertion sites are oval. The gladius does not invade the posterior tail-like extension of the mantle as found in Ornithoteuthis, among others. DESCRIPTIVE ACCOUNTS Subfamily Ommastrephinae Steenstrup, 1857 Genus Ommastrephes d'Orbigny, 1835 Ommastrephes bartramii (Lesueur, 1821) Material examined.—4M, ML = 283-205 mm, GL = 287-108 mm, R/V VELERO, no data (probably eastern Pacific Ocean), UMML 31.1770. —1F, ML = 241 mm, GL = 237 mm, Naples, Italy, ANSP A6474. — 1F, ML = 142 mm, GL = 149 mm, R/V AT- LANTIS, off Bermuda, surface night light, 11 Oct. 1937, MCZ 293702. Description. —Cross sections (Fig. 3): Level A—The medial axis is subellipsoid, wider than deep, and broadly attached to the thin, medial plate. The lateral plates are mod- erately thick, distally tapered to blunted points or rounded tips and ventrally recurved. There are paired lateral axes. The proximal axis is digitiform and curved in some specimens. The distal axis is subovoid and wider than deep. Both axes are broadly attached to the lateral plate; Level B—The medial complex is similar in size and shape to that of level A. The lateral complexes are irregularly multi- lobed; Level C—The medial complex is small and fusiform. The lateral complexes are an inflated hook-shape. The admedial cleft is quadrangular to triangular and about one- third to one-half as wide as the complex. 316 1 —=— Level В TOLL 2 o e ER A + —— Level À — CE > я fi % Cd d f" IM К us. | k à m A LA A Level D м y n w ic o < ed ne 2 Medial Axial Complex (re NET Axial Complex ——— Level С 10) © (re Ф = o O - + Conus FIG. 1. Diagrammatic ventral view of ommastrephid gladius. FIG. 2. Composite cross sections of gladius with level of sections corresponding to Fig. 1 [a-lateral field; b-medial plate; c-medial commissure; d-medial axis; e-lateral plate; f-lateral axis (single); f-proximal lateral axis; f”-distal lateral axis; g-lateral commissure; h-accessory process; i-admedial cleft; j-ventromedial рго- cess; k-lateral process; l-dorsal carina; m-body; n-ventral keel]. All sections oriented with dorsal surface toward top of page. There is a small ventromedial process; Level D— The body is subtriangular with a pair of large quadrangular, ventral keels and stout, dorsally upswept, lateral processes that taper to blunt points. The dorsal carina is stout and slightly inflated apically. Discussion.—The gladii show variation in the shape of the lateral thickenings at all lev- els and the overall shape at Level D. This variation was seen as varying degrees of thickness and shape of the axis and plate components and is greater than in any other ommastrephid species examined. The six Ommastrephes bartramii examined here were from distant localities—the Mediterra- nean Sea, western Atlantic Ocean and Pacific ‚ Осеап. Prevailing taxonomic uncertainties as well as geographic variation probably account for at least part of this variation. Genus Sthenoteuthis Verrill, 1880 Sthenoteuthis pteropus (Steenstrup, 1855) Material examined.—1F, ML = 328 mm, GL = 351mm, DISC 425E, Atex Drift, 12°27'N, 41°21’W, dip net with night light, 12- 13 Feb. 1969, UMML. —2F, ML = 288 mm, GL = 304-286 mm, DISC 425E, Atex Drift, 10°51'N, 42°21'W, dip net with night light, 14- 15 Feb. 1969, UMML. —3F, ML = 305—178 mm, GL = 317—175 mm, DISC 425E, Atex Drift, 12°57'N, 40%09'W, dip net with night light, 9-10 Feb. 1969, UMML. —2F, ML = OMMASTREPHID GLADIUS MORPHOLOGY 317 u с. > „en ee FIGS. 3-9. Stylized composite cross sections of gladius levels A-D (see text for explanations of arrows): Fig. 3. Ommastrephes bartramii; Fig. 4. Sthenoteuthis pteropus; Fig. 5. S. oualaniensis; Fig. 6. Dosidicus gigas; Fig. 7. Eucleoteuthis luminosa; Fig. 8. Ornithoteuthis antillarum; Fig. 9. Hyaloteuthis pelagica. 318 Ec Dd a ,„ BD TOLL 11 FIGS. 10-17. Stylized composite cross sections of gladius levels A-D (see text for explanations of arrows): Fig. 10. Мех coindetti; Fig. 11. I. oxygonius; Fig. 12. Todaropsis eblanae; Fig. 13. Todarodes sagittatus; Fig. 14. T. pacificus; Fig. 15. Nototodarus sloani; Fig. 16. N. hawaliensis; Fig. 17. Martialia hyadesi. OMMASTREPHID GLADIUS MORPHOLOGY 319 265—134 mm, GL = 256-132 mm, DISC 425E, Мех Drift, 12°45’N, 40°38’W, dip net with night light, 10-11 Feb. 1969, UMML. — EMI = 211 ши, @Ё = 207 mm; DISC 425E, Atex Drift, 13°43’N, 38°58’W, dip net with night light, 6-7 Feb. 1969, UMML. Description.—Cross sections (Fig. 4): Level A— The medial axis is subellipsoid and wider than deep. The medial commissure is only slightly constricted. The lateral plates are broad, thin, and distally tapered to narrow points and ventrally recurved. The two paired lateral axes are spindly. The distal one is bifid. The proximal lateral axis is digitiform, curved medially and swollen apically in some speci- mens. The lateral commissures are con- stricted; Level B—The medial complex is similar in shape and slightly smaller than that of level A. The proximal lateral axis is broader than that of level A. The distai lateral axis is subquadrangular, wider than deep, broadly joined to the lateral plate, and slightly incised ventrally in some specimens. The accessory process is most commonly “‘U’’-shaped, con- cave dorsally, but is lobate in one specimen; Level C—The medial complex is spindle- shaped. The lateral complexes are hook- shaped. The deep, medially facing subtrian- gular to sickle-shaped admedial cleft is about two-thirds to three-quarters of the width of the complex. There is a small ventromedial pro- cess; Level D—The body is subtriangular, broadest ventrally, with a pair of subquadran- gular to lobate, ventral keels and a pair of dorsally curved lateral processes that taper to acute points. The dorsal carina is inflated api- Cally. Sthenoteuthis oualaniensis (Lesson, 1830) Material examined.—1F, ML = 317 mm, GL = 341 mm, НОЕ Cr. 4B, 273B, 20°50'N, 59°10'E, 4 Dec. 1963, night light and hand- line, UMML 31.1812. —1F, ML = 170 mm, GL = 178 тт, 10°N, 92°30’E, night light and dipnet, Nov.-Dec. 1961, USNM 656967. —1F, ML = 138 mm, GL = 143mm, Moorea Island, Society Islands, 15 Apr. 1937, ANSP A6364. —1M, ML = 123 mm, GL = 128mm, Moorea Island, Society Islands, 15 Apr. 1937, ANSP A6357. —1F, ML = 115 mm, GL = 121 mm, Moorea Island, Society Islands, 15 Apr. 1937, ANSP A6347. —1sex?, ML = 42 mm, GL = 45 mm, SHOYO MARU Sta. 12, 2322515; 9), 1104-36-80 W,, 21) Yan: 1963, in stomach of Alepisaurus, UMML 31.1360. Description. —Cross sections (Fig. 5): Level A—The medial axis is ellipsoid, wider than deep, and attached to the medial plate by acommissure that is about one-half to two- thirds of the axis width. The lateral plates are broad, thin, tapered distally to a narrow point and ventrally recurved. There are paired lat- eral axes. The proximal lateral axis is digiti- form and slightly curved medially. The distal one is narrow, deep, and slightly constricted basally. In two specimens, the proximal lat- eral axes are absent. In another specimen, the distal lateral axes are slightly bifurcated ventrally. There is a small, domelike protuber- ance on the ventral surface of the lateral plates distal to the distal lateral axis (arrow); Level B—The medial axis is similar in shape and size to that in level A but is more broadly attached to the medial plate. The lateral plate and distal lateral axis are fused into a single, quadrangular axis. A digitiform proximal axis is present in those specimens with a proximal lateral axis in level A. The lateral process is bulbous and connected to the distal surface of the lateral complex by a stalklike commissure (arrow); Level C—The medial complex is fusiform. The lateral complexes are hook- shaped. The deep, broadly excavated adme- dial cleft if subtriangular to irregularly polygo- nal and equal in depth to about one-half of the width of the complex. A small, ventromedial process is present; Level D—The body is roughly triangular, broadest ventrally, with a pair of stout, angular, ventral keels and a sin- gle dorsal carina that is slightly expanded api- cally. The stout lateral processes are dorsally curved and taper to rounded tips. Remarks.—The absence of proximal lateral axes in two specimens is peculiar in compar- ison with the levels of intra-specific variability exhibited in all other taxa examined. | suspect that the difference is the result of prevailing systematic problems that could have con- fused proper species-level identification. Genus Dosidicus Steenstrup, 1857 Dosidicus gigas (d’Orbigny, 1835) Material examined.—1 sex?, ML = 360 mm, GL = 412 mm, Chinchua Norte, Peru, 16 Oct. 1941, MCZ 293699. —1M, 1F, ML = 349—298 mm, GL = 315—299 mm, R/V ALASKA Cr. 74A6, Sta. 59, “coastal waters” off La Jolla, California, USNM 729467. —2F, ML = 224—174 mm, GL = 254-204 mm, IATTC (28), off Manta, Ecuador, Apr. 1962, UMML 31.1769. 320 TOLL Description.—Cross sections (Fig. 6): Level A—The ellipsoid medial axis is rela- tively shallow and narrow, wider than deep and attached to its plate Бу a commissure that is about one-half of the axis width. The lateral plates are relatively thick, distally attenuate and strongly ventrally recurved. There are paired lateral axes. The proximal lateral axis is digitiform. The distal lateral axis is subellip- soid to subtriangular, wider than deep, and attached to the lateral plate by a constricted commissure that is about one-half of the width of the axis; Level B— The medial complex is similar in shape and slightly smaller than that of level A. Both lateral axes are broadly fused dorsally to the lateral plate. The lobate acces- sory process is joined by a narrow, stalk-like commissure; Level C—The medial complex is fusiform. The lateral complexes are a deeply excavated C-shape. The ventromedial process is small; Level D—The body is sub- triangular, broadest ventrally, with a pair of stout, quadrangular, ventral keels. There is a tall, medially constricted, dorsal carina. The dorsally curved lateral processes are rela- tively long and taper to rounded tips. Genus Eucleoteuthis Berry, 1916 Eucleoteuthis luminosa (Sasaki, 1915) Material examined.—1F, ML = 177 mm, GE = 170) mm: ММЕ-А55-1Е7Т, 137125. 8°58'W, 6 Apr. 1971, USNM 730198. —1M, ML = 151 mm, GL = 155 mm, ANTON BRUUN Cr. 17, 29°22'S, 79°57'W, dip net with night light, July 1966, MCZ 278110. — 1sex?, ML = 98 mm, GL = 99 mm, SHOYO MARU Sta. 16, 16°25.0'S, 96°58.3’W, 13 Jan. 1963, in stomach of Alepisaurus, UMML 31.1558. —4sex?, ML = 96-89 mm, GL = 101-89 mm, SHOYO MARU Sta. 16, 16° 25.0'S, 96°58.3'W, 13 Jan. 1963, in stomach of Thunnus obesus, UMML 31.1557. Description.—Cross sections (Fig. 7): Level A—The medial axis is ovoid to subellipsoid, wider than deep, and is broadly attached to the medial plate. The lateral plates are broad, di- stally tapered to a narrow rounded tip and ven- trally recurved. The single lateral axis is sub- ovoid, wider than deep, and broadly attached to the plate; Level B—The medial complex is similar in shape and about one-half to one- third of the size of that in level A. The lateral axis and plate are broadly fused. The lobate accessory process is separated from the plate by an offset pair of proximal, ventral and distal, dorsal sulci (arrows); Level C—The medial complex is subcylindrical and minute. The lat- eral complexes are bullet-shaped to lobate, rounded laterally with a pair of small, ventro- and dorsomedial processes (arrows). An ad- medial cleft is absent; Level D—The body is subcylindrical with a shallow, ventral sulcus (arrow) between a pair of low, dome-like ven- tral keels. The lobate, slightly dorsally curved lateral processes are broadly attached to the body. The short, relatively broad, dorsal carina is slightly inflated apically. Genus Ornithoteuthis Okada, 1927 Ornithoteuthis antillarum Adam, 1957 Material examined.—1M, ML = 179 mm, GE = 175mm, ORE ll Gr 232 Заза: 12°54'N, 70°31'W, 0-732m, 24 Feb. 1973, trawl, UMML 31.1726. —4F, ML = 164—123 mm, GL = 147—125 mm, ORE 3250, 29°14'N, 87°40'W, 0-732 m, 60’ MWT, 26 Apr. 1961, UMML 31.397. —1M, 1F, ML = 157—129 mm, GL = 147—116 mm, ORE 3670, 20°00.5'N, 88°22’W, 732 m, 40’ flat trawl, 30 July 1962, UMML 31.438. —1M ML = 155 mm, GL = 133mm, ORE*2944* 27°40'N, 90°50'W, 60’ MWT, 183-229 m, 24 Aug. 1960, UMML 31.253. —1M, 1F, ML = 153—126 mm, GL = 136—115 mm, ORE 3254, 29°00'N, 88°02'W, 247 m, 60’ MWT, 27 Apr. 1961, UMML 31.476. —2F, ML = 149— 104 mm, GL = 129—91 mm, ORE 5449, 19°55'N, 68°57'W, night light, 1 June 1971, UMML 31.1618. —1M, ML = 101 mm, GL = 95 mm, Cl-264, 23°53.4'N, 77°08.9'W to 23°54.7'N, 77°11.7'W, 1301-1329 Ар Standard Blake Trawl, 3 Nov. 1974, UMML 31.1670. —1M, ML = 75 mm, GL = 70 mm, ORE 1959, 26°55'N, 89°10'W, 2269 m, 23 Sept. 1957, UMML 31.213. Description.—Cross sections (Fig. 8): Level A— The medial axis is massive, subcy- lindrical, broader than deep, and broadly at- tached to the medial plate. The lateral plates are thick, slightly recurved ventrally and broadly rounded laterally. The single lateral axis is massive, ovoid, broader than deep, with a broad commissure; Level B—The me- dial complex is similar in shape and about one-third smaller than that of level A. The lat- eral complexes are massive, subovoid, with a broad, shallow, ventrolateral sulcus; Level C—The lateral fields are narrow, thick, and extend from the ventrolateral borders of the massive subovoid medial complex. The lat- eral complexes are subovoid and slightly con- cave laterally. An admedial cleft is absent; OMMASTREPHID GLADIUS MORPHOLOGY 321 Level D—The body is rectangular, wider than deep, with shallow, broad, ventral and lateral sulci (arrow). The carina is relatively tall and broadly inflated dorsally. Remarks.—The narrow, thick lateral fields reflect the greater tapering of the posterior portion of the free rachis in this species as compared to all other ommastrephids. Genus Hyalotuthis Gray, 1849 Hyaloteuthis pelagica (Bosc, 1802) Material examined.—3M, 1F, ML = 73— 50 mm, GL = 79 - 56mm, DEL Il, Acre 12- 81-N, 32°09'N, 64°07'W, 0-150 m, 1400 mesh ET, 24 Aug. 1971, USNM 728882. — 1М, 2F, ML = 72—68 mm, GL = 76—75 mm, DEL Il, Acre 12-79-N, 32°08'N, 64°09'W, 0-450 m, 1400 mesh ET, 23 Aug. 1971, USNM 728881. —1Е, ML = 64 тт, GL = 71 mm, SHOYO MARU Cr. 12, Fish Sta. 20, 23`255'5, 104°36.8:W, 21 Jan: 1963, in stomach of Alepisaurus, UMML 31.1561. — 2F, ML = 61—57 mm, GL = 65— 63mm, SHOYO MARU Cr. 17, Fish Sta. 19, 19°37.7'W, 108°27.7'W, 19 Jan. 1963, in stomach of Alepisaurus, UMML 31.1560. Description. —Cross sections (Fig. 9): Level A—The medial axis is small, subovoid to subcylindrical and broadly attached to the narrow medial plate. The lateral plates are ventrally recurved distally and taper to rounded points. The single lateral axis is large, three to four times as wide as the me- dial axis, subovoid, broader than deep, and broadly attached to the plates; Level B—The medial axis is broadly joined to the medial plate. The lateral complexes are unequally bi- lobed with a dorsal and ventral pair of oppos- ing, shallow, broad sulci (arrows); Level C— The medial axis is minute and subcylindrical. The medial plate is highly reduced. The lat- eral complexes are subovoid with a “U”- shaped admedial cleft equal in depth to about one-quarter of the complex width. The ventro- medial process is small and dome-like; Level D— The body is broadly contiguous with the lobate, slightly dorsally curved lateral pro- cesses. The ventral sulcus is broad and shal- low. The carina is slightly inflated apically. Subfamily Illicinae Posselt, 1890 Genus /llex Steenstrup, 1880 Illex coindetti (Verany, 1837) _Material examined.—1F, ML = 189 mm, GL = 222 mm, Cette, France, June 1861, MCZ 2304. —2M, 2F, ML = 185—122 mm, GL = 180—128 mm, P-82, 4°57'N, 9°30'W to 4°58'N, 9°32’W, 144m, 5 June 1964, UMML 31.1335. —1F, ML = 171 mm, GL = 178 mm, Naples, Italy, ANSP A8008. Description.—Cross sections (Fig. 10): Level A—The medial axis is subellipsoid, wider than deep, with a narrow commissure. The lateral plates are broad and thick, ven- trally recurved distally, and tapered to rounded tips. There are paired lateral axes. The proximal one is subtriangular and rounded apically. The distal lateral axis is subovoid, wider than broad, and attached to the plate via a slightly constricted commis- sure; Level B—The medial complex is similar in shape and slightly smaller than that in level A. The lateral complexes are broad, irregu- larly lobate with two, shallow, ventral sulci (arrows); Level C—The medial axis is subcy- lindrical and broadly fused to the reduced plate. The lateral complexes are large and subovoid and with a weakly scalloped ventral Outline. The ventromedial process and adme- dial cleft are highly reduced to absent; Level D—The body and weakly dorsally curved lat- eral processes are broadly contiguous and collectively bilobed with a shallow ventral sul- cus. The dorsal carina is inflated apically. Illex oxygonius Roper, Lu, & Mangold, 1969 Material examined.—1M, 1F, ML = 205— 184 mm, GL = 209-193mm, ORE 5784, 24°28'N, 83°39'W, 567m, UMML 31.899. — 2F, 1M, ML = 148—108 mm, GL = 162— 118 mm, TRITON, south of Palm Beach Inlet, Florida, 165 m, 26 May 1953, ANSP A8079. Description. —Cross sections (Fig. 11): Level A—The medial axis is ovoid to ellipsoid, twice as wide than deep, and broadly attached to the medial plate. The lateral plates are thick, ventrally curved distally and taper to broadly rounded tips. There are paired lateral axes. The proximal lateral axis is broad, low and apically rounded. The distal lateral axis is ir- regularly lobate to subrectangular with rounded edges and broadly joined to the lat- eral plate; Level B— The medial complex is similar in shape and one-third to one-half the size of that of level A. The lateral complexes are large, laterally rounded, with two or three ventral sulci; Level C—The medial complex is similar in shape and about one-third smaller than that of level B. The lateral complexes are massive and subovoid. The ventromedial pro- 322 TOLL cess is dome-like. The admedial cleft is highly reduced to absent; Level D—The body and weakly dorsally curved lateral processes are broadly contiguous and collectively bilobed with a shallow ventral sulcus. The dorsal ca- rina is inflated apically. Genus Todaropsis Girard, 1890 Todaropsis eblanae (Ball, 1841) Material examined.—1M, 1F, ML = 131— 114mm, GL = 133—120 mm, Atlantique Sud Sta. 154. 0°15'S, 8°47'E, 239 m, 15 Mar. 1949, UMML 31.1351. —2M, 1F, ML = 89— 78 mm, GL = 90—76mm, Geronimo Sta. 2- 236, 4°03'S, 10°22’E, 0-201 m, bottom trawl, 8 Sept. 1963, USNM 730204. —2M, 3F, ML = 68—46 mm, GL = 70—46 mn, P-254, 3°50'N, 7°08’E to 3°51'N, 7°12’E, 172-148 m, 14 May 1965, 40’ OT, USNM 727408. Description —Cross_ sections (Fig. 12): Level A—The medial axis is massive, subel- lipsoid and twice as wide than deep. The me- dial commissure is about one-third as wide as its axis. The lateral plates are relatively nar- row, ventrally recurved distally and taper to a narrow rounded tip. The single lateral axis is subovoid to subellipsoid, wider than deep, about one-half as wide as the medial axis, and broadly joined to the lateral plate; Level B—The medial complex is similar in shape and size to that in level A. The lateral com- plexes are irregularly lobate and subequal in width to the medial complex; Level C—The medial complex is large and fusiform. The lat- eral complexes are irregular with a shallow, admedial cleft and small ventromedial pro- cess; Level D—The body and lateral pro- cesses are relatively small and collectively subrectangular. The dorsal carina is stout and slightly inflated dorsally and forms a right an- | gle with respect to the body to give an overall appearance of a “1” shape. Subfamily Todarodinae Adam, 1960 Genus Todarodes Steenstrup, 1880 Todarodes sagittatus (Lamarck, 1799) Material examined.—1M, ML = 186 mm, GL = 178 mm, R/V TRIDENT, 36°55’N, 01°04'W, 143— 150 m, 10'IKMT, 21-22 Aug. 1970, USNM 727741. Description —Cross_ sections (Fig. 13): Level A—The medial axis is subovoid, wider than deep and broadly attached to the medial plate. The lateral plates are relatively thin, slightly curved ventrally and taper to rounded tips. The single lateral axis is relatively small, subovoid and wider than deep; Level B— The medial complex is similar in shape and slightly smaller than that in level A. The lateral com- plexes are roughly bilobed with slightly offset dorsal, distal and proximal, ventral sulci; Level C—The medial complex is similar in shape and about one-half of the size of that of level B. The lateral complexes are hook-shaped. The admedialcleftis roughly “V”-shapedwitha depth of about one-third of the complex width. The ventromedial process is small and dome- like, Occasionally reduced; Level D—The body is broadly attached to the large, dorsally curved lateral processes and has a small ven- tral sulcus. The lateral processes terminate in rounded lobes. The carina is tall, relatively nar- row, and inflated apically. Todarodes pacificus Steenstrup, 1880 Material examined.—2F, ML = 302—287 mm, GL = 301—292 mm, 40°16’N, 133°14.5’E, night angling, 7 Sept. 1967, USNM 730206. Description.—Cross sections (Fig. 14): Level A—The medial axis is irregularly ovoid, slightly wider than deep, and broadly attached to its plate. The lateral plates are thick, ven- trally curved and digitiform distally. The single lateral axis is ovoid to subovoid and wider than deep. The lateral commissure is about two-thirds of the width of the axis; Level B— The medial complex is similar in shape and slightly smaller than that in level A. The lateral axis is Subellipsoid, broader than deep. The relatively large accessory process is sepa- rated from the lateral plate by an offset pair of narrow, deep, proximal ventral, and relatively broad, shallow, distal dorsal sulci. In some specimens the accessory process is pedun- culate; Level C—The medial complex is sub- fusiform. The lateral complexes are large and hook-shaped with an angular, admedial cleft equal in depth to about one-quarter of the complex width. The ventromedial process is small and dome-like; Level D—The body is broadly attached to the large, dorsally curved lobate, lateral processes. The carina is sub- trapazoidal, broad basally and tapers apically to a broadly rounded tip. Genus Nototodarus Pfeffer, 1912 Nototodarus sloanii (Gray, 1849) Material examined.—1F, ML = 194 mm, GL = 214 mm, Tasmania, Jan. 1875, USNM 576996. —2M, ML = 170—160 mm, GL = OMMASTREPHID GLADIUS MORPHOLOGY 323 183—-172 mm, Auckland, New Zealand, Jan. 1953, USNM 575461. Description.—Cross sections (Fig. 15): Level A—The medial axis is subovoid and broader than deep. The medial commissure is about one-half as wide as the axis. The lateral plates are relatively thick, ventrally recurved and bluntly pointed laterally. The single lateral axis is subovoid, wider than deep; Level B— The medial axis is ovoid, subequal in width to that of level A. The commissure is only slightly constricted. The lateral axis and plate, and in some specimens the accessory process, are broadly fused into a broad, roughly bilobed lateral complex with a pair of opposing shal- low, broad, dorsal and ventral sulci. In some specimens the accessory process is irregu- larly lobate and more distinctly set off from the plate by a deep, narrow, ventral sulcus; Level C—The medial complex is small and subfusi- form. The lateral fields are narrow. The lateral complexes are subovoid with a small adme- dial cleft equal in depth to about one-fifth of the complex width. The ventromedial process is small and dome-like; Level D—The body is broadly fused to the large, lobate, dorsally curved lateral processes. The ventral sulcus is shallow and broad. The carina is inflated apically. Remarks.—In a single specimen (USNM 576996), the cross sections at levels B and D were grossly asymmetrical and anomalous. The cause of this condition is unknown. The animal was normal in all other respects and was apparently unaffected by this condition. Nototodarus hawaiiensis (Berry, 1912) Material examined.—1F, ML = 104 mm, GL = 122 mm, TC-36, Sta. 24, 21°09.7'N, 157°29.3’W to 21°09.8'N, 157°24.6'W, 183 m, 4-5 May 1968, USNM 730203. —2F, ML = 114—93 mm, GL = 114—99 mm, TC-35, Sta. 15, 21%05'N, 156°26’W to 21°05’М, 156°32’W, 361 m, 1 Apr. 1968, USNM 730201. —1M, ML = 88 тт, GL = 92 mm, TC-32, Sta. 2, 21°21.9'N, 158°12.4’W, 65- 110 m, 12 July 1967, USNM 730202. Description.—Cross sections (Fig. 16): Level A—The medial axis is subellipsoid, wider than deep, and broadly attached to the medial plate. The lateral plates are ventrally recurved distally and end in narrow blunted tips. The single lateral axis is small, subovoid, wider than deep, and broadly attached to the plate; Level B—The medial complex is simi- lar in shape and size to that of level A. The lateral axis is subrectangular, wider than deep. The accessory process is lobate to sub- spherical and separated from the lateral axis and plate by a single narrow, ‘‘V’’-shaped ven- tral sulcus; Level C—The medial complex is similar in shape and about one-half of the size of that of level B. The lateral complexes are ovoid to lobate. The admedial cleft is small and rounded. The medial process is small and domelike; Level D—The body is small. The lateral processes are relatively small, dorsally curved and bluntly rounded apically. The ventral sulcus is shallow and broad. The dorsal carina is rectangular, stout, and slightly inflated apically. Genus Martialia Rochebrune & Mabille, 1889 Martialia hyadesi Rochebrune & Mabille, 1889 Material examined.—3M, ЗЕ, ML = 338— 286 mm, GL = 340-288 mm, ELT Cr. 23, Sta. 8c, 59°29'S, 102°30’W, rod and reel, 18-19 Apr. 1966, UMML 31.1768. Description.—Cross sections (Fig. 17): Level A— The medial axis is subellipsoid, two to three times wider than deep. The medial plate is reduced. The medial commissure is narrow, about one-third the width of the me- dial axis. The lateral plates are ventrally re- curved distally and taper to blunt points. The single lateral axis is subovoid to irregular. The lateral commissure is narrow, about one-half the width of the axis; Level B—The medial axis is small, subtriangular, and wider than deep. The medial plate is reduced. The lateral axis is polygonal to irregular. The lateral com- missure is constricted, about one-half the width of the axis. The irregularly lobate lateral process is separated from the lateral plate by a pair of deep, offset proximal, ventral and dorsal, distal sulci; Level C—The medial complex is subfusiform. The lateral com- plexes are subovoid with a “V”-shaped adme- dial cleft that is equal in width to about one- third to one-quarter of the complex width. The ventromedial process is small; Level D—The body is subtriangular, broader than deep, with a narrow, deep, ventromedial sulcus. The dorsally upswept lateral processes are mod- erately angular and taper to rounded tips. The dorsal carina is narrow and inflated apically. GENERAL DISCUSSION The overall shape of the ommastrephid gla- dius is strikingly conservative as compared to 324 ТОЕЕ all other speciose, and many of the less spe- ciose, teuthoid families, which show a greater range of intrafamilial variation (Toll, 1982). Therefore, the degree of variability in the structure of the gladius, as evidenced by cross sectional morphology, is surprising, even in light of earlier reports that provided some information on cross sections. Sample sizes of the 15 species treated here ranged from one to 14 specimens. Moreover, the col- lection of specimens from several taxa were heterogeneous with respect to geographical distribution, sex, and to a limited extent, size. As a result, intraspecific variability cannot be rigorously assessed here. However, several preliminary statements can be made at this time. The major diagnostic features associ- ated with each taxon do not vary within that taxon. These include the single vs. double (i.e. proximal and distal) lateral axes along the anterior region of the free rachis (level A) (with the exception of two specimens of Sthe- noteuthis oualaniensis, see Remarks, that taxon), accessory processes along this same region, hook-shaped vs. lobate lateral com- plexes along the posterior portion of the free rachis (level C), presence or absence of keels and carina and the basic shape of the axial axis at the posterior terminus of the free ra- chis (level D), relative sizes of the medial and lateral axes, and degree of posterior tapering of the medial axis. Intra-specific variability was recognized in terms of the precise shape of free rachis axes, and depth and distinctive- ness of sulci dividing free rachis axes and separating the accessory processes from the lateral plates. Out of a total 89 ommastrephid gladii, one (1.1%) showed gross structural anomalies (see Nototodarus sloanii). Relationships among species and genera of ommastrephids are immediately apparent based on the cross sectional shape of their gladi. Ommastrephes bartramii, Stheno- teuthis pteropus, S. oualaniensis, and Dosidi- cus gigas form a distinct clade sharing a dig- itiform to vermiform proximal lateral axis at level A (with the exception of the two variant specimens of S. oualaniensis) and paired, quadrangular keels at level D. Eucleoteuthis luminosa and Hyaloteuthis pelagica form a second clade sharing a small medial axis at level A that tapers to become minute at level D. The remaining ommastrephine, Ornitho- teuthis antillarum, is unique in the relative and absolute sizes of the medial and lateral axes at levels A through C and the rectangular body at level D. In support of their congeneric placement, /llex coindetti and I. oxygonius form а clade sharing a broadly rounded distal terminus of the lateral plate at level A, general shape of the lateral axes and relative sizes of the medial and lateral axes at levels B and C, and overall shape at level D. Todaropsis ebla- nae is distinct from /llex based on many char- acters, the most salient being the relative sizes of the medial and lateral axes at levels A through C and the overall shape of level D. Clear relationships among the Todarodinae are more difficult to establish based on char- acters of the gladius alone. Martialia is unique in the degree of constriction of the medial commissure at levels A and B and the deep ventral sulcus at level D. The two species of Todarodes and the two species of Nototo- darus studied here show no more similarity between congeners than between nonconge- ners. Therefore, based on these characters, these two genera appear to be closely re- lated. Some of these groupings are congruent with some of the findings of Zuev et al. (1975), Wormuth (1976) and Roeleveld (1988), all based on a suite of traditional soft tissue char- acters. In particular, Wormuth's groups A (Symplectoteuthis [= Sthenoteuthis] ouala- niensis, Dosidicus, and Ommastrephes) and В (Symplectoteuthis [= Sthenoteuthis] lumi- nosa and Hyaloteuthis), which are equivalent to Roeleveld’s (1988: fig. 1) clades based on nodes E and G, respectively, are well sup- ported by the present findings; Wormuth's group C (Ornithoteuthis volatilis, Illex illece- brosus, and Todarodes pacificus) is not. The relatively isolated position of Ornithoteuthis within the Ommastrephinae as indicated by Roeleveld’s (1988) node D is corroborated by the present study. Her findings on the interre- ‚ lationships of the genera within the Todarodi- nae and Illicinae are supported in part, insofar as her figure 1 shows an unresolved tricotomy including all three subfamilies at node A. (However, in the text (p. 287) she indicates that the Illicinae are separable on the basis of several characters, in particular the condition of eight sucker rows on the dactylus of the tentacular club.) Based on characters of the gladius alone, there is no support for the cur- rent subfamilial classification within the Om- mastrephidae. Cross sections of ommastrephid gladii clearly show laminae indicative of accretive growth. This can be seen easily with either light or scanning electron microscopy. The particular distinctiveness of this layering in the OMMASTREPHID GLADIUS MORPHOLOGY 325 FIGS. 18-20. Sthenoteuthis pteropus, scanning electron micrograph of gladius level D. Fig. 18 whole view; Fig. 19. Enlargement of Fig. 18 in body area near basal portion of ventral keel; Fig. 20. Enlargement of Fig. 19 to show changes in radius of arc of depositional layers during ontogeny. Ommastrephidae, as compared to most teuthoid gladii wherein laminations are more difficult to resolve, allows easy observation of the change in the shape of cross sections dur- ing ontogeny. For example, the strong qua- drangular keels at level D of the gladius of Sthenoteuthis pteropus begin as small, rounded, dome-like protuberances (Figs. 18- 20). Also, examination of the whole cross sec- tion immediately suggests longitudinal struc- tural continuity between the hook-shaped lateral complexes at level C and the lateral processes at level D. The same conclusion applies to the medial axis of levels A through C, which forms the nucleus of the dorsal ca- rina at level D. Future examination of layering patterns could provide valuable evidence re- lating to ontogenetic precedence of cross sectional shape that could in turn be used to establish evolutionary polarity of these char- acter states for incorportation in phylogenetic analyses. ACKNOWLEDGMENTS The late Gilbert L. Voss provided material for study and lent extensive encouragement and advise. Discussions with Clyde Е. E. Roper and Stephen C. Hess, and conversa- tions with and a review of the manuscript by John H. Wormuth, were of great value. Com- ments on the manuscript by Martina Roele- veld were also valuable. George Davis and Robert Robertson made possible and as- sisted me during a visit to the Academy of Natural Sciences of Philadelphia, which was supported by a grant from the Jessup- McHenry fund of the Academy. Ruth Turner assisted me during my stay а the Museum of Comparative Zoology, Harvard University, which was supported by a grant from the Lerner Fund for Marine Research (#5-19-80; 103045). The larger study of teuthoid gladii, of which this contribution is а part, was sup- ported in part by a Dissertation Improvement 326 TORE Grant (DEB-8012544) from the National Sci- ence Foundation, a visiting Graduate Student Award from the Smithsonian Institution Office of Fellowships and Grants, and grants from the Bader Fund of the Rosenstiel School of Marine and Atmospheric Science, National Capital Shell Club, Astronaut Trail Shell Club, and Key Biscayne Women's Club. | gratefully acknowledge the support provided to me from these many persons and institutions. LITERATURE CITED ADAM, W., 1975, Notes sur les Cephalopodes. XXVI. Une nouvelle espéce de Todarodes (To- darodes filippovae sp. nov.) de l'Océan Indien. Bulletin de L'Institut Royal des Sciences Na- turelle de Belgique, 50(9):1-10. BALL, R., 1841, On a species of Loligo found on the shore of Dublin Bay. Proceedings of the Royal Irish Academy, No. 19:362-364, 7 figs. CLARKE, M. R.. 1966, Review of the systematics and ecology of oceanic squids. Advances in Ma- rine Biology, 4:91—300. DONOVAN, О. Т. & В. В. TOLL, 1988, The gladius in coleoid evolution. In: The Mollusca, Vol. 12. Paleontology and Neontology of Cephalopods. CLARKE, М. В. & Т. В. TRUEMAN, eds. pp. 89— 101. Academic Press, London. LESUEUR, C. A., 1821, On several new species of cuttle-fish. Journal of the Academy of Natural Sciences of Philadelphia, 2:86-101. LU, C. C. & M. DUNNING, 1982, Identification guide to Australian arrow squid (family Ommas- trephidae). Technical Report, Victorian Institute of Marine Science, 2:1-30. NAEF, A., 1923, Cephalopoda. Fauna and Flora of the Bay of Naples, Monograph 35, Part 1, Vol. 1, Fasc. Il, рр. 293-917. (English Transl. Israel Pro- gram for Scientific Translation No. TT 68-50343/ 2, Jerusalem, 1972). NESIS, K. N., 1978, [Evolutionary history of the nekton.] Zhurnal Obshchei Biologii, 39(1):53—65 (in Russian, English summary). NESIS, K. N., 1983, Dosidicus gigas. In: Cephalo- pod Life Cycles, Vol. 1. Species Accounts. BOYLE, P. R., ed. pp. 215-231. Academic Press, London. O'DOR, В. K., 1983, Шех illecebrosus. In: Cephalo- pod Life Cycles, Vol. 1. Species Accounts. BOYLE, P. R., ed. pp. 175-199. Academic Press, London. OKUTANI, T., 1983, Todarodes pacificus. In: Ceph- alopod Life Cycles, Vol. 1. Species Accounts. BOYLE, P. R., ed. рр. 201-214. Academic Press, London. PFEFFER, G., 1912, Die Cephalopoden des Plank- ton Expedition. Ergebnisse der Plankton Expedi- tion Humboldt-Stiftung., 2:1-815 + atlas. POSSELT, H. J., 1890, Todarodes sagittatus (Lmk.) Stp. En anatomisk studie. Videnskabelige Meddelelser fra Danske Naturhistorisk Forening i Kjobenhavn, 1890: 301-359. RANCUREL, P., 1970, Les contenues stomacaux d’Alepisaurus ferox dans le Sud-ouest Pacifique (Céphalopodés). Cahiérs de Office de la Re- cherche Scientifique et Technique Outre-Mer, Ser. Océanographique, 8(4):3-87. RATHJEN, W. 8 G. L. VOSS, 1987, The cephalo- pod fisheries, a review. In: Cephalopod Life Cy- cles, Vol. Il. Comparative reviews. BOYLE, P. R., ed. pp. 253-275. Academic Press, London. ROELEVELD, M. A., 1982, Interpretation of tentac- ular club structure in Sthenoteuthis oualaniensis (Lesson, 1830) and Ommastrephes bartramii (Lesueur, 1821) (Cephalopoda, Ommastre- phidae). Annals of the South African Museum, 89(4):349-264. ROELEVELD, M. A., 1988, Generic interrelation- ships within the Ommastrephidae (Cephalo- poda). In: The Mollusca. Vol. 12. Paleontology and Neontology of Cephalopods. CLARKE, М. В. 8 T. R. TRUEMAN, eds. рр. 277-291. Academic Press, London. ROPER, С. Е. E., 1983, An overview of cephalopod systematics: status, problems and recommenda- tions. Memoirs of the National Museum of Victo- па, No. 44:13-27. ROPER, С. Е. Е., С. C. LU 8 К. MANGOLD, 1969, A new species of /llex from the Western Atlantic and distributional aspects of other /llex species (Cephalopoda: Oegopsida). Proceedings of the Biological Society of Washington, 82:295-332. SASAKI, M., 1929, A monograph of the dibranchi- ate cephalopods of the Japanese and adjacent waters. College of Agriculture, Hokkaido Imperial University, 20 Suppl., 357 pp. STEENSTRUP, J., 1857, Prof. Steenstrup foreviste og beskrev nogle nye blaeksprutter, Dosidicus Eschrichtii Stp. og Onychoteuthis (?). 1856-57: 120-121. TOLL, R. B., 1982, The comparative morphology of the gladius in the Order Teuthoidea (Mollusca: Cephalopoda) in relation to systematics and phy- logeny. Doctoral Dissertation, University of Mi- ami, Florida. 390 pp. VERRILL, A. E., 1882, The Cephalopods of the Northeastern Coast of America. Reprinted from the Report of the Fisheries Commission for 1879, Government Printing Office, Washington, D.C. 244 pp. WORMUTH, J. H., 1976, The biogeography and nu- merical taxonomy of the oegopsid squid family Ommastrephidae in the Pacific Ocean. Bulletin of the Scripps Institution of Oceanography, 23, 90pp. ZUEV, С. V., К. N. NESIS, & С. М. NIGMATULLIN, 1975, [Systematics and evolution of the squid genera Ommastrephes and Symplectoteuthis (Cephalopoda, Ommastrephidae)]. Zoologis- cheskii Zhurnal, 54(10):1468-1479 (In Russian, English summary). Revised Ms. accepted 15 November 1989 MALACOLOGIA, 1990, 31(2): 327-352 COMPARISON OF RECENT CLASSIFICATIONS OF STYLOMMATOPHORAN LAND-SNAIL FAMILIES, AND EVALUATION OF LARGE-RIBOSOMAL-RNA SEQUENCING FOR THEIR PHYLOGENETICS Kenneth С. Emberton', Gerald $. Kuncio*, George M. Davis’, $. Michael Phillips”, Kathleen М. Monderewicz*, and Yuan Hua Guo? ABSTRACT Morphological approaches to the phylogenetic relationships among stylommatophoran fami- lies have not reached a consensus. We compare in tabular form the recent classifications of Solem, Boss, Schileyko, Nordsieck, and Тег, and find that they differ up to 52%, 79% and 74% at the ordinal, subordinal, and superfamilial levels. To explore the utility of molecular sequence data for resolving sylommatophoran phylogeny, we sequenced regions of large ribosomal RNAs (LrRNAs) of 10 species, exemplars of Archae- ogastropoda, Mesogastropoda, Basommatophora, Holopodopes, Aulacopoda, and Holopoda. One divergent domain, D6, its conserved flanking regions, and the highly conserved 5’ end of LrRNA were sequenced by a rapid and versatile primer-directed method. Sequencing a total of 177 nucleotide sites yielded 61 variable positions. Four polygyrids (two polygyrines and two triodopsines) had identical sequences, and two zonitids differed at a single position. Three different phylogenetic analyses (maximum parsimony, and UPGMA on simple and K,,„. distance matrices) resulted in the same topology: (Нейста (Oncomelania (Bi- omphalaria (Neohelix-Triodopsis-Mesodon (Haplotrema (Ventridens-Mesumphix)))))), except that the phenograms did not resolve the final three taxa. Standard errors for K,,. values indi- cated no significant resolution of the four stylommatophoran families, however. Among the three stylommatophoran families (Polygyridae, Haplotrematidae, and Zonitidae), only 1% of nucleotide positions were variable in the 5'-terminal and the D6-flanking regions, but fully 13% of nucleotide positions were variable within the D6 divergent domain. Our results demonstrate the potential usefulness of this approach, and we predict that divergent domains of the LrRNA molecule will be of some value in resolving stylommatophoran phylogeny. Key words: land snail families, phylogenetics, RNA, nucleotide sequences, Stylommatophora, Archaeogastropoda, Mesogastropoda, Basommatophora. INTRODUCTION There are probably more species of land snails (estimated 30,000-35,000) than of land birds, mammals, reptiles and amphibi- ans combined (Solem, 1984). The vast ma- jority of land snails are stylommatophoran pulmonates, of which there are 71 to 92 fam- ilies, according to recent classifications. Sty- lommatophorans are ancient; fossils date from the mid Paleozoic, and most seem as- signable to Recent families, implying that ra- diation into higher taxa occurred soon after invasion of land (Solem & Yochelson, 1979). Large land snails and some small ones are relatively poor dispersers. This combination of ancient origin, slow evolution at higher tax- onomic levels, and often low vagility makes pulmonate land snails superb biological indi- cators of early tectonic and geomorphological events (Peake, 1978; Solem, 1979a, 1979b, 1981; Nordsieck, 1986). The biogeographic value of pulmonate land snails has been severely limited, however, by the lack of a robust phylogenetic inference for their families. Thus there are major discrep- ancies among the five suprafamilial classifi- cations of pulmonate land snails that have been published within the past 12 years. These classifications differ in the data used, the methodology employed, or both. Solem (1978) presented a slightly modified version of the traditional Pilsbry-Baker scheme, based primarily on excretory, locomotory, and genitalic gross anatomy, using an evolution- ary approach, presenting no formal phylog- Department of Malacology, Academy of Natural Sciences, 19th & the Parkway, Philadelphia, Pennsylvania, U.S.A. 19103 “Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A. 19104 | 3Institute of Parasitic Diseases, Chinese Academy of Preventive Medicine, Shanghai, People’s Republic of China 328 EMBERTON ET AL. eny but a hierarchically arrayed classification. Boss (1982) gave an apparently strictly phe- netic classification. Sharply departing from these was Schileyko's basically evolutionary approach (1979; edited and translated into English by Boss & Jacobson, 1985) based primarily on shell and reproductive morphol- ogy. The first overtly cladistic approach was by Nordsieck (1985, 1986), who reintegrated and reinterpreted the widely scattered litera- ture primarily on reproductive and excretory characters and secondarily on shell features. The most recent and most thorough effort to date was Tillier's (1989) presentation of major new data sets on the digestive, nervous, and excretory systems, which he subjected to a kind of cladistic analysis. In sum, the system- atics methods have ranged from evolutionary to phenetic to cladistic; and the data bases have ranged from primary emphasis on, to no emphasis on, reproductive morphology, all in- corporating only subsets of available anatom- ical data. No molecular data yet exist for fam- ily comparisons. The efficacy of large ribosomal RNA se- quencing for resolving evolutionary relation- ships among taxa has been well demon- strated (e.g., Qu et al., 1989; Guadet et al., 1989; Larson & Wilson, 1989; Lenaers et al., 1989). This molecule consists of rapidly evolving segments (divergent domains) inter- spersed among extraordinarily conserved segments. These conserved regions yield phylogenetic information at several higher taxonomic levels, and can also be used to target and to establish the homologies of di- vergent domains. The taxonomic level at which divergent domains are useful as sources of phylogenetic information differs widely among organisms: for example, at the family level in salamanders (Larson & Wilson, 1989), but at the species level in both the fun- gus Fusarium (Guadet et al., 1989) and the prosobranch gastropod Truncatella (Rosen- berg & Kuncio, in preparation). Among the lo- gistic advantages of the LrRNA molecule for land-pulmonate studies are its presence in high concentrations in all tissues (allowing small samples to be used), and the rapidity with which it can be extracted and sequenced under various states of preservation (allowing efficient accumulation of data). The purposes of this paper are (1) to as- sess quantitatively the levels of discrepancy among the family-level stylommatophoran classifications of Solem, Boss, Schileyko, Nordsieck, and Tillier; and (2) to evaluate the applicability to stylommatophoran family-level phylogenetics of LrRNA sequencing. MATERIALS AND METHODS Distances Among Classifications The five stylommatophoran classifications (Appendix) were compared at three taxo- nomic levels: superfamily, suborder, and or- der. At each level, the distance between each pair of classifications was calculated as the number of families differently classified, di- vided by the total number of families classified by both. Whenever the taxonomic names dif- fered, names were equated in such a way as to maximize the similarities of their grouped families. Thus the following equations were used, with the authors’ names abbreviated So for Solem, Sh for Schileyko, B for Boss, N for Nordsieck, and T for Tillier. At the ordinal level (called subordinal by B and T): Sh Geophila and Athoracophora = T Dolichonephra and Brachynephra; B Heterurethra = N Elasmog- natha; B and So Sigmurethra and Mesurethra = T Dolichonephra and Brachynephra; Sh Geophila = So Sigmurethra; Sh Geophila and Succineida = B Sigmurethra and Heter- urethra; Sh Geophila and Succineida = N Sigmurethra and Elasmognatha; and N Sig- murethra and Elasmognatha = T Dolichone- phra and Brachynephra. At the subordinal level (called infraordinal by B): So Orthure- thra, Holopodopes, and Aulacopoda = Sh Achatinina, Pupillina, and Helixina; So Hol- opodopes and Holopoda = N Achatinida and Helicida; Sh Pupillina, Achatinina, Helixina, and Succineida = В Orthurethra, Hol- opodopes, Aulacopoda, and Heterurethra = N Orthurethra, Achatinida, Helicida, and Elas- mognatha; Sh Pupillina = T Orthurethra; and B Holopodopes, Holopoda, and Heterurethra — N Achatinida, Helicida, and Elasmognatha. At the superfamily level: Sh Vitrinoidea and Limacoidea = So Limacacea A and B; So Succinacea = B unnamed subfamilies of suborder Heterurethra; N Cochliocopoidea, Orthalicoidea, Helixarionoidea, and Mesod- ontoidea = So Cionellacea, Bulimulacea, Limacacea A, and Polygyracea; T Zonitoidea = So Limacacea В; Sh and В Succineidae were judged the same ranking for both, though unnamed by either; N Cochlioco- poidea = Sh Cionelloidea; N Cochlioco- poidea, Orthalicoidea, and Mesodontoidea = B Cionellacea, Bulimulacea, and Polygyra- STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 329 cea; and Т Zonitoidea = В Limacacea. We emphasize that these are not taxonomic de- cisions, but simple expedients—often Pro- crustean—for calculating differences among the five classification schemes. Each of the three resulting distance matrices was ana- lyzed by UPGMA clustering, using a hand cal- culator. RNA Sequence Analysis LrRNA sequences were obtained from 10 snail species representing the stylommato- phoran suborders (according to Solem, 1978) Holopodopes [one lot the haplotrematid Hap- lotrema concavum (Say) (ANSP A12650, KCE32, collected Madison County, Alabama, 5-7 May 1988 by K. C. Emberton)], Aula- copoda [one lot each of the zonitids Ventri- dens cerinoideus (Anthony) (KCE24, col- lected Mcintosh County, Georgia, 15 April 1988 by K. C. Emberton) and Mesomphix latior (Pilsbry) (ANSP A12649, KCE32, col- lected Madison County, Alabama, 5-7 May 1988 by K. C. Emberton)], and Holopoda [one lot each of the triodopsine polygyrids Neohe- Их (= Xolotrema = Triodopsis) albolabris (Say) (ANSP 373132, collected Gilchrist County, Virginia, June 1987 by T. Asami) and Triodopsis hopetonensis (Shuttleworth) (= Т. fallax hopetonensis) (ANSP 373135, col- lected Whitley County, Kentucky, 1 Decem- ber 1987 by D. Stephens), and of the polygy- rine polygyrids Mesodon normalis (Pilsbry) (ANSP 373133, collected Gilchrist County, Virginia, June 1987 by T. Asami) and Mes- odon inflectus (Say) (ANSP 373134, col- lected Jessamine County, Kentucky, 30 November 1987 by D. Stephens)], as well as the outgroup taxa Archaeogastropoda [one lot of the helicinid Helicina orbiculata (Say) (ANSP A12648, KCE32, collected Madison County, Alabama, 5-7 Мау 1988 by К. С. Emberton)], Mesogastropoda [one lot of the pomatiopsid Oncomelania hupensis (Gredler) (ANSP 375731, collected Hanyang, Hubei, People’s Republic of China, 25 November 1985 Бу С. М. Davis & У. H. Guo)], and Ba- sommatophora [one lot of the planorbid Bi- omphalaria glabrata (Say) (= В. диаае- loupensis) (ANSP A12651, from aquarium culture, Department of Medicine, University of Pennsylvania)]. Specimens were prepared for RNA extrac- tion in one of the following ways: (1) snails were killed and immediately stored by freez- ing at —80°C. Feet and terminal genitalia were later dissected from semi-thawed snails, frozen directly in liquid nitrogen, and re-stored at —70°C until homogenized (Neohelix albo- labris, Mesodon normalis); (2) feet and termi- nal genitalia were dissected from live snails and stored directly in liquid nitrogen until ho- mogenized (Biomphalaria glabrata, Mesodon inflectus, some Triodopsis hopetonensis); (3) snails were killed and stored by freezing at —80°C, then homogenized whole, shell and all (Oncomelania hupensis, Ventridens cerinoides, Mesomphix latior, Haplotrema concavum, Anguispira alternata); and (4) live, whole snails were homogenized, shell and all (some Triodopsis hopetonensis). RNA analy- sis was performed on both single snails and several specimens for most species. Total RNA was extracted by a modification of the method of Auffray & Rougeon (1980). One to two grams of tissue were homoge- nized using a polytron (Brinkmann) in 6 M urea, 3 М LiCI. Debris was removed by low- speed centrifugation. The supernatant was stored overnight at 4°C. The formed RNA pre- cipitate was collected by centrifugation. The RNA was then solubilized and exhaustively extracted with phenol-chloroform (1:1), chlo- roform, then ether. Following ethanol precip- itation, the RNA was collected by high speed centrifugation and was resuspended in water to a concentration of approximately 1 mg/ml. Sequencing of the LrRNAs was performed using methods modified from Qu et al. (1983) and Lane et al. (1985). Oligonucleotide prim- ers were synthesized at the DNA Synthesis Facility of the University of Pennsylvania. The two primers used correspond to sequences that are extremely conserved in LrRNAs throughout all five kingdoms of life and are complements of the mouse sequence (Has- souna et al., 1984) as follows: 5'-terminus: nucleotides 52 through 66 D6 region: nucleotides 2099 through 2118 For sequencing purposes each primer was end-labelled with 92P under standard condi- tions with T4 polynucleotide kinase and датта-АТЗ?Р (Maniatis et al., 1982), an- nealed to total RNA, and elongated with AMV reverse transcriptase in the presence of deoxy- and dideoxy-nucloside triphosphates at 50°C. Samples were electrophoresed, the gel dried and autoradiographed. Following film development, the sequences were read and entered into the computer using the IBI/ Pustell DNA Sequence Analysis software. Ini- tial alignment of sequences was performed 330 EMBERTON ET AL. using this program; the results were then modified manually. Multiple sequencing runs were made for each species. Replicate runs were used to resolve sequence ambiguities where possi- ble. In some cases, the identification of an individual base could not be determined, and these bases were not used in phylogenetic analyses. We estimate the error rate for iden- tification of the bases used in the analysis to be well under 1%. Variable nucleotide positions among the aligned sequences were analyzed both cla- distically and phenetically. Cladistic analysis employed the Wagner criterion of unrestricted parsimony (Kluge & Farris, 1968; Farris, 1970), with character states unordered. He- licina orbiculata was used as the outgroup for rooting the cladogram. For tree construction, we chose the branch-and-bound algorithm (Hendy & Penny, 1982), which assures max- imum parsimony (Swofford, 1985). Trees were generated not only of minimum length n, but also of lengths n+ 1 and n+ 2. PAUP pro- grams (Swofford, 1985), run on a personal computer, were used for all cladistic analy- ses. For phenetic analysis of the sequence data, two separate UPGMA clusterings were per- formed from distinctly different distance ma- trices. The first distance measure used was the proportion of common nucleotide posi- tions showing any kind of difference. This was calculated for each pair of taxa by counting the number of nucleotide differences between them, without correction for multiple changes at one given site, and then by dividing this count by the total number of comparable nu- cleotide positions for the pair. The second dis- tance measure was Kimura's (1980) Ku. in- dex, which incorporates the possibility of. transitions occurring more frequently than transversions. For this index, the proportion of different sites was partitioned into that due to transitions (i.e. purine to purine or pyrimidine to pyrimidine) versus that due to transver- sions (purine to pyrimidine and vice versa), deletions, and insertions. These proportions were used to calculate values of not only Кис but also its standard error, using formulae given in Kimura (1980). The relative rates of nucleotide substitution in divergent domains and conserved regions of stylommatophorans were compared by cal- culating the percent variable positions in the D6 domain versus the 5’ terminus plus the D6 flanker regions. RESULTS Distances Among Classifications The five stylommatophoran classifications are summarized in the Appendix. The dis- crepancies among them are analyzed in Ta- ble 1 in the form of distance matrices, and in Figure 1 in the form of UPGMA phenograms, at three levels of classification: order (or sub- order), suborder (or infraorder), and super- family. Even using the most conservative pos- sible estimates (e.g. equating differently named largest categories), differences ranged to 52%, 79%, and 74% at the ordinal, subordinal, and superfamilial levels respec- tively (Table 1). The Solem and Boss classi- fications cluster closest at all three taxonomic levels, since both are based primarily on the Pilsbry-Baker scheme; nevertheless, they dif- fer substantially (20%) in superfamilial assig- nation. Nordsieck’s reclassification produced little change at the ordinal level, but major change at the subordinal and superfamilial levels. Both Schileyko’s conchological-repro- ductive and Tillier's non-reproductive anatom- ical revisions differ дгеаНу from these three classifications and from each other at all three levels (Table 1, Fig. 1). RNA Sequence Analysis Nucleotide-sequence data for the 10 gas- tropod species are presented in Figure 2. No differences were detected within species. At the 5’ termini of LrRNAs, 39 nucleotides were sequenced, of which five (13%) were variable among the 10 taxa. The D6 region showed much greater variability (41%), with 56 vari- able positions among the 138 that were se- quenced. There was greater variability in the D6 region itself (positions 1 to 41) than on either side of it (positions —42 to —1 and 42 to 96), with 83% and 23% variable nucleotide sites respectively. The great majority of this variation lay be- tween the set of stylommatophorans and the set of outgroups. No differences whatever were detected among the four species of po- lygyrids. Cladistic analysis of this variation produced a single most parsimonious tree with a con- sistencey index of 0.90 (0.74 if all autapomor- phies were removed), which is presented in Figure 3 and Table 2. This cladigram had a tree length of 72. Three cladograms were also produced with tree lengths of 73 (consistency STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 331 Solem Boss Nordsieck Tillier Schileyko Order (or Suborder ) Level Solem Boss Schileyko Nordsieck Tillier Suborder (or Infraorder ) Level Solem Boss Nordsieck Schileyko Tillier Superfamily Level 100 90 80 70 60 50 40 30 20 10 0 FIG. 1. UPGMA phenograms of the past decade's five classifications of pulmonate land-snail families, by author, at three taxonomic levels. The common scale is percent difference in classification of all families common to each pair of classifications, as conservatively calculated from the Appendix. 332 EMBERTON ET AL. TABLE 1. Distances among recent stylommato- phoran classifications at the superfamilial, subordinal, and ordinal levels. So = Solem (1978), Sh Schileyko (1979), В = Boss (1982), N = Nordsieck (1985, 1986), and T = Tillier (1989). The upper matrix gives the number of families compared; the lower matrix is the proportion of compared families differently classified. Ordinal So Sh B N T So — 64 65 67 56 Sh 0.31 — 62 69 54 B 0.06 0.32 — 64 52 N 0.09 0.22 0.09 — 56 Subordinal So Sh B N Тр So a 60 65 63 56 Sh 0.38 — 61 69 53 B 0.08 0.30 — 64 52 М 0.44 0.38 0.45 — 55 1! 077 0.79 0.75 0.78 — Superfamilial So Sh B N ale So — 64 64 66 55 Sh 0.61 — 63 68 54 В 0.20 0.59 — 63 51 М 0.39 0.53 0.48 — 54 iT; 0.62 0.74 0.61 0.74 = index = 0.890). Each of these differed from Figure 3 in only a single detail: pairing On- comelania with Biomphalaria, pairing Hap- lotrema with Mesomphix, and pairing Hap- lotrema with Ventridens, respectively. Four slightly less parsimonious cladograms (length = 74, consistency index = 0.878) were also. produced. Two of these paired Oncomelania with Biomphalaria, one also pairing Hap- lotrema with Mesomphix, the other also pair- ing Haplotrema with Ventridens. The third 74- length cladogram differed from Figure 3 by placing Biomphalaria between the Polygy- ridae and the remaining stylommatophorans, and the fourth cladogram differed by pairing Biomphalaria with the Polygyridae. Phenetic analyses of sequence data are presented in Tables 3, 4, and 5; and in Figure 4. Table 3 presents, for each pair of taxa, the numbers of nucleotide site differences and of total sites compared, used in calculating sim- ple distance coefficients. Table 4 partitions the proportion of different sites into that due to transitions versus that due to transversions, deletions, and insertions. Kimura’s (1980) ev- olutionary distance K,,,,, and its standard error are presented in Table 5. UPGMA clustering from Table 5 yielded the phenogram in Figure 4, which includes stan- dard error bars. This tree is almost identical in topology to the cladogram in Figure 3, with the exception that Haplotrema, Mesomphis, and Ventridens form an unresolved trichot- omy. The standard error bars in Figure 4 in- dicate significant differences among all branch points, except the branch point be- tween the Polygyridae and the three other stylommatophoran families. UPGMA clustering from values of the pro- portion of different sites (Tables 3 and 4) re- sulted in a phenogram identical in topology to Figure 4, and virtually identical to it in branch- point distances as well. In Figure 4, the branch-point distances, from top to bottom, are 0.020, 0.038, 0.104, 0.187, and 0.283; whereas in the phenogram based on propor- tion of different sites (not figured), the branch- point differences are 0.020, 0.030, 0.097, 0.165, and 0.232. Among the seven species of stylommato- phorans sequenced, there was variation at five of the 40 positions of the D6 divergent domain (positions #16, 27, 29, 31, and 36). At these positions there were five interfamilial differences and one intrafamilial difference (position #16 in Zonitidae). Thus in this re- gion of the molecule, 13% of the sites were phylogenetically informative. The conserved regions, on the other hand, had only 1% infor- mative sites: sequencing 137 positions in the 5'-terminus and in the flanker regions of D6 yielded only one position (#83) that differed among the stylommatophorans. DISCUSSION Comparison of Classifications A systematic discussion of the recent clas- sifications of the stylommatophorans (com- pared in Appendix) is beyond the scope of this paper. All we have done is point out the high degree of taxonomic discrepancies among them (Table 1, Fig. 1). These discrep- ancies can be attributed to a number of fac- tors: (1) use of different characters (e.g. Tilli- er's unique use of the digestive and nervous systems but not the reproductive system); (2) emphasis on different characters (e.g. Schil- STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 333 Selected Large Ribosomal RNA Sequences 5' termini Е Cn ULES UU BCE ey For OO EU 10 20 30 D6 region Ho ----G-A---C-A--AG---C-CGGXC-C--U-.---CX--- Ho Oh ---0-6------ ===, .----.C---.---C-A--- Oh D6 5'-flanks CCCUGAAAAUGGAUGGCGCUAGAGCGUCXGACCCAUACCG . GC VOD OO 10 20 30 40 AGUAGGAGGGCCGUCGGGGUGAGCGUGGAAGCCUGGGGAGUGAUCCUGGGUGGAG FIG. 2. Nucleotide sequence data for 10 species of gastropods from the 5’ termini and the D6 regions of large ribosomal RNA molecules. Ho = Нейста orbiculata, Oh = Oncomelania hupensis, Bg = В! omphalaria glabrata, Hc = Haplotrema concavum, MI = Mesomphix latior, Vc = Ventridens cerinoideus, Mi = Mesodon inflectus, Mn = Mesodon normalis, Na = Neohelix albolabris, and Th = Triodopsis hopetonensis. Dash = absent. eyko’s strong emphasis on shell characters); (3) different interpretation of the same char- acters (e.g. Nordsieck’s and Schileyko's dif- ferent opinions on the homologies of genital appendages); and (4) different methodologies (e.g. Solem’s intuitive evolutionary approach versus ТШег$ more objective cladistic approach). At least partial resolution of these factors is possible by careful analysis of all available characters in order to construct an integrative phylogenetic hypothesis, which is urgently needed. Accurate detection of ho- mologies in many anatomical and concholog- ical characters, however, may never be pos- sible. Stylommatophoran families are simply so old, and their environmental selective pressures so similar (see Solem, 1978), that convergences and parallelisms are pervasive (e.g. Tillier, 1989). If there is any remedy for this systematic dilemma, it probably lies in the application of new, independent data sets, of which molecular sequences currently seem most promising. same as polygyrids (given below, with position numbers), X = unknown, period = RNA Sequence Analysis There is a burgeoning literature on the phy- logenetic interpretation of nucleotide se- quence data, with many alternative ap- proaches (e.g. Felsenstein, 1982; Wolters & Erdmann, 1986; Sourdis & Krimbas, 1987; Saitou & Nei, 1987; Lake, 1987a, 1987b; Sai- tou, 1988; Sourdis & Nei, 1988; and refer- ences therein). We chose three approaches (maximum parsimony, simple distance UP- GMA, and K,. distance UPGMA) that have held their own in the ongoing controversy or have been applied recently to LrRNA (Guadet et al., 1989; Larson & Wilson, 1989; Qu et al., 1989) or other rRNA data (Bremer & Bremer, 1989). We did not adjust either for compen- satory changes in the D6 stem region (see Wheeler & Honeycutt, 1988) or for possible multiple changes at a given site (e.g. Holmquist, 1983), and we do not know whether these would substantially change our results. 334 EMBERTONET AL. 4(2) 3(5) 2(13) 1 (31) 11 (6) FIG. 3. Maximum-parsimony cladogram from the nucleotide sequence data presented in Fig. 2. The con- sistency index is 0.90 (but is 0.74 if all autapomorphies are removed). The numbers refer to the lists of apomorphies as listed in Table 2, with the number of apomorphies in parentheses. The three phylogenetic approaches gave identical results (Figs. 3, 4), with the excep- tion that maximum parsimony cladistics re- solved the trichotomy among Haplotrema, Ventridens, and Mesomphix, by pairing the latter two by means of a single synapomorphy (Table 2, #8). This agreement among meth- odological approaches provides reasonable confidence that Figure 3 is a robust interpre- tation of the sequence data at hand. Haszprunar (1988) recently presented a cladistic analysis of the major gastropod groups, with explicit and thorough character analyses from a range of sources. For the taxa we have analyzed, his phylogram agrees with all previous hierarchically arranged classifications (e.g. Taylor & Sohl, 1962) in the arrangement: (Helicina (Oncomelania (Pulmonata))), which appears as (*Arch- aeogastropoda*: Neritimorpha (*Apogastro- poda*: *Neotaenioglossa* (Euthyneura))) in Haszprunar's (1988) figure 5 and as the more STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 335 TABLE 2. Character-state transformations in the 5’ and D6 regions of large ribosomal RNAs of stylommatophoran gastropods and three outgroups. Numbers 1-11 refer to the cladogram in Figure 3. Derived from sequences given in Fig. 2, and presented here by region, nucleotide position(s), and suggested transformation. m 5’ end D6 5’ flank D6region D6 3’ flank Ile 10 G<>A ZPICEA SIG 5AC<>U 15 A<>G -19 D<>U 7 A<>G 59 C<>U 23 G<>U —13.@<-А 1 С=-А 64 D<>A 29 C<>G 13 A<>D 67 A<>G M6 <=>U 79 A<>G 19 A<>U 80 G<>A 2C<=U 87 C<>U 23C<>G 88 U<>C 24 G<>A 25 G<>A 27C<>G 32 U<>A 34 6<_-@ 35 9=<-6 36 D<> 38 С<>А 2. 11 С-0 С SV 78 G >А -7 A>U 6C >G BIC -3D >G 14°C: =D 16А >G 22-23 P >С зза =D STEH IE 39G >A 3. 17 А >С SICH >G 22. EG 26-27 P >D s2A =D 4. 16A >G 836 0 5° no transformations 6. 16A >G 59 G >А 7e 16A >G 1G. SA 8. SAG 9. 27С >А 29А >С SOLU CE 10. UEG 19U >A 56:6 = U —10 U >C SHAUEC 80 À >G 87 USC Wale -2A>G 29С >А 59U>G 69C>G 81 C>A 86 G >U familiar (Archaeogastropoda (Mesogas- tral tree in Figure 5, namely: (Basommato- tropoda (Pulmonata))) in, for example, Taylor & Sohl (1962). Our LrRNA data confirm this phylogenetic hypothesis (Figs. 3, 4). This cor- roboration between anatomical and molecular data lends credence to both. Within the Pulmonata we sequenced, the resulting topology is summarized by the cen- phora (Polygyridae (Haplotrematidae (Zoniti- dea)))). For comparison, Figure 5 also presents the trees for these taxa as presented in Schileyko (1979: fig. 7, as translated by Boss & Jacobson, 1985) and Tillier (1989: text-figs. 25 and 29b), and as inferred from the hierarchical classifications of Solem 336 EMBERTON ET AL. TABLE 3. Number of nucleotide differences (upper matrix) and total number of comparable nucleotide positions (lower matrix) between pairs of sequences aligned in Fig. 2. “Polygyridae” pools the four species that were sequenced and found to be identical at all 177 positions examined. He. On. Bi. Ha. Me. Ve. Po. Helicina — 43 39 24 35 37 36 Oncomelania 170 — 28 29 29 31 27 Biomphalaria 174 172 —= 16 19 18 16 Haplotrema 165 163 168 — 3 3 5 Mesomphix 172 170 1174 167 — 4 8 Ventridens 170 169 AS 167 172 6 Polygyridae 174 172 10707 168 175 173 — TABLE 4. Proportions of compared nucleotide sites different due to transitions (upper matrix) and transversions plus deletions/insertions (lower matrix). He. On. Bi. Ha. Me. Ve. Po. Helicina — 0.12 0.092 0.085 0.093 0.094 0.092 Oncomelania 0.141 — 0.047 0.086 0.088 0.089 0.064 Biomphalaria 0.132 0.116 — 0.054 0.069 0.069 0.051 Haplotrema 0.121 0.092 0.042 — 0.018 0.012 0.030 Mesomphix 0.110 0.082 0.040 0.000 — 0.017 0.046 Ventridens 0.124 0.095 0.035 0.006 0.006 — 0.029 Polygyridae 0.115 0.093 0.040 0.000 0.000 0.006 = TABLE 5. Values of Kimura’s (1980) evolutionary distance K,,,. (upper matrix) and its standard error (lower matrix) between pairs of sequences aligned in Fig. 2. He. On. Bi. Ha. Me. Ve. Po. Helicina = 0.310 0.267 0.241 0.238 0.258 0.243 Oncomelania 0.051 — 0.184 0.204 0.195 0.211 0.176 Biomphalaria 0.045 0.036 — 0.102 0.118 0.113 0.097 Haplotrema 0.044 0.040 0.026 = 0.018 0.018 0.031 Mesomphix 0.043 0.038 0.028 0.011 — 0.024 0.048 Ventridens 0.045 0.040 0.028 0.011 0.012 — 0.036 Polygyridae 0.043 0.035 0.025 0.014 0.017 0.015 — (1978) and Nordsieck (1986). (No tree is pre- sented for Boss [1982], because his classifi- . cation is not explicitly hierarchical, but if it were, the tree would probably equal that for Solem [1978].) In these four trees from the literature, the Basommatophora appear as the sister group to the three stylommatophoran families, in Schileyko’s tree by explicit inclusion, in the other three trees by implicit assumption, be- cause that is the traditional taxonomic posi- tion of the Basommatophora. The LrRNA se- quence data corroborate this relationship (Fig. 5, center), with the Basommatophora (as represented by Biomphalaria glabrata) join- ing the base of the stylommatophoran clade. This sister-group status of the Basommato- phora to the Stylommatophora has been called into question by Solem (1985; see also Solem & Yochelson [1979]) because (a) the earliest known basommatophoran fossils ap- pear about 150 million years later than the earliest known stylommatophoran fossils, and (b) there is no convincing anatomical evi- dence of a sister-group relationship. Our data do not contradict this opinion; the real test will require sequencing at least one of the four Recent stylommatophoran families that ap- pear in the Paleozoic (Tornatellinidae, an un- assigned pupillacean family, Enidae, and Dis- cidae [Solem & Yochelson, 1979]). We can at least say with fair confidence that the Basom- matophora are plesiomorphic to the stylom- matophorans included in this study. Concerning the relationship among the Po- lygyridae, the Haplotrematidae, and the STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 337 1 3 FIG. 4. UPGMA phenogram from K,,,,, distances (Table 5, top) calculated from the nucleotide sequence data presented in Fig. 2. Standard error bars are averaged from those presented in Table 5 (bottom). Zonitidae, our RNA sequence data do not These two phylogenetic hypotheses differ support any recently proposed phylogeny, but most strikingly from the others in placing the are closest to that of Schileyko (1979) (Fig. 5). Polygyidae as most plesiomorphic. This 338 EMBERTON ЕТ AL. So B H 2 Р В Р М Sh NA H 7 à FIG. 5. Comparison of proposed phylogenies for selected pulmonate snail taxa. B = Basommatophora, P — Polygyridae, H = Haplotrematidae, Z = Zonitidae. Central tree is derived from LrRNA sequence data (Figs. 3, 4); other trees from: So = Solem (1978), Sh = Shileyko (1979), N = Nordsieck (1986), T = Tillier (1989). In each tree, taxa are arranged from the most plesiomorphic (left) to most apomorphic (right). strong contrast from the traditional Western classification, although not statistically signif- icant according to K,,,,, analysis (Fig. 4), hints of many possible surprises to come as the result of future molecular sequence studies with greater numbers of phylogenetically in- formative positions. Within the Polygyridae, the lack of se- quence divergence between the subfamilies Triodopsinae and Polygyrinae is remarkable, considering their great anatomical differences (e.g. Emberton, 1986). In summary, the LrRNA molecule presents many opportunities for comparative analysis at a hierarchy of taxonomic levels (Guadet et al., 1989; Larson & Wilson, 1989; Lenaers et al., 1989; Qu et al., 1989). We chose the 5 terminus and one divergent domain for an ini- tial analysis. It is instructive to extrapolate from our results in order to predict the poten- tial value of the LrRNA molecule for stylom- matophoran systematics. Clearly, the con- served regions are unproductive, at less than 1% informative sites among three families. It is in the divergent domains that sequencing efforts are rewarded. LrRNA contains 12 di- vergent domains (D1-D12), of which D6 can be assumed to be at or below average in number of nucleotide sites (e.g. Hassouna et al., 1984; Hancock et al., 1988). In D6 we found five informative sites out of 40 among the three stylommatophoran families se- STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 339 quenced. Thus, at 13% informative sites, Lr- RNA divergent domains afford a high return for the effort. Including more families would certainly increase this percentage. Mining more of this phylogenetic informa- tion would prove a useful adjunct to the ana- tomical data already available (and in need of synthesis) for the Stylommatophora. Such ef- forts will be aided by our discoveries that (1) whole-snail preparations can be used, mak- ing it possible to include such generally minute-sized families as pupillids, ferrussaci- ids, and valloniids; and (2) turnaround time from sample receipt to sequence recording can be a mere three days per divergent do- main, running up to 12 samples simulta- neously. ACKNOWLEDGMENTS This work was funded by NIH grant Al15193 to S.M.P., NIH grant TMP-AI11373 and NSF grant BSR-85002796 to G.M.D., and NSF grant BSR-8700198 to K.C.E. We are also grateful to J. Wright (ANSP) for word processing, to L. Carrozza for drafting Figures 1 and 3, to J. Hendrickson (ANSP) for com- puter help, to G. Rosenberg (ANSP) for as- sistance in running PAUP, to Rosenberg and to G. Harasewych (United States National Museum) for helpful discussion, and to C. Stine and two anonymous reviewers for help- ful criticism of the penultimate draft of this pa- per. We also express thanks to those who provided specimens, as mentioned in the text. LITERATURE CITED AUFFRAY, C. & F. ROUGEON, 1980, Purification of mouse immunoglobulin heavy-chain messen- ger RNAs from total myeloma tumor RNA. Euro- pean Journal of Biochemistry, 107: 303-314. BOSS, K. J., 1982, Mollusca. In: PARKER, S. P. (ed.), Synopsis and Classification of Living Or- ganisms 1: 945-1166. McGraw-Hill, New York. BOSS, K. J. & M. K. JACOBSON, 1985, The sys- tem of the order Geophila (=Helicida) (Gas- tropoda Pulmonata) by А. A. Schileyko ... An edited translation. Department of Mollusks, Har- vard University Special Occasional Publication No. 6: 1-45, Figs. 1-10. BREMER, B. & K. 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Solem, 1978 Family Order Suborder Superfamily Achatinellidae Gulick, 1873 Orthurethra — Achatinellacea Tornatellididae Cooke & Kondo, 1960 Orthurethra — Achatinellacea' Amastridae Pilsbry, 1911 Orthurethra — Cionellacea Cionellidae (= Cochliocopidae) Clessin, 1879 Orthurethra — Cionellacea Pupillidae Turton, 1831 Orthurethra —- Pupillacea Vertiginidae Fitzinger, 1833 Orthurethra — Pupillacea® Orculidae Pilsbry, 1918 Orthurethra — Pupillacea? Chondrinidae Steenberg, 1925 Orthurethra — Pupillacea? Pleurodiscidae Wenz, 1923 Orthurethra -- Pupillacea Pyramidulidae Wenz, 1923 Orthurethra — Pupillacea? Valloniidae Morse, 1864 Orthurethra — Pupillacea Strobilopsidae Pilsbry, 1918 Orthurethra -- Pupillacea Partulidae Pilsbry, 1900 Orthurethra — Partulacea Enidae (= Buliminidae) Clessin, 1879 Orthurethra — Partulacea Clausiliidae Mörch, 1864 Mesurethra — Clausiliacea Cerionidae (= Ceriidae) Fleming, 1818 Mesurethra = Clausiliacea Dorcasiidae Connolly, 1915 Mesurethra — Strophocheilacea Strophocheilidae Thiele, 1926 Mesurethra — Strophocheilacea Ferussaciidae Bourguignat, 1883 Sigmurethra Holopodopes Achatinacea Subulinidae Crosse & Fischer, 1877 Sigmurethra Holopodopes Achatinacea Spiraxidae Baker, 1955 Sigmurethra Holopodopes Achatinacea Megaspiridae Pilsbry, 1904 Sigmurethra Holopodopes Achatinacea Achatinidae Swainson, 1840 Sigmurethra Holopodopes Achatinacea Streptaxidae Gray, 1840 Sigmurethra Holopodopes Streptaxacea Haplotrematidae H.B. Baker, 1925 Sigmurethra Holopodopes Rhytidacea Systrophiidae Thiele, 1926 Sigmurethra Holopodopes Rhytidacea Rhytididae (= Paraphantidae) Pilsbry, 1893 Sigmurethra Holopodopes Rhytidacea Aperidae (= Chlamydephoridae) Möllendorff, 1902 Sigmurethra Holopodopes Rhytidacea Macrocyclidae Thiele, 1926 Sigmurethra Holopodopes Rhytidacea? Acavidae ‘ Pilsbry, 1895 Sigmurethra Holopodopes Acavacea? Clavatoridae Thiele, 1926 Sigmurethra Holopodopes Acavacea?* Caryodidae Thiele, 1926 Sigmurethra Holopodopes Acavacea? (continued) 342 EMBERTON ЕТ AL. APPENDIX. (Continued) Schileyko, 1979 Family Order Suborder Infraorder Superfamily Achatinellidae Geophila Pupillina Gulick, 1873 Ferussac, 1812 Schileyko, 1979 Achatinelloidea Tornatellididae Cooke & Kondo, 1960 — — Le en Amastridae Pilsbry, 1911 Geophila Pupillina — Cionelloidea Cionellidae ( = Cochliocopidae) Clessin, 1879 Geophila Pupillina — Cionelloidea Pupillidae Turton, 1831 Geophila Pupillina == Pupilloidea Vertiginidae Fitzinger, 1833 Geophila Pupilina — Pupilloidea Orculidae Pilsbry, 1918 Geophila Pupillina = Achatinelloidea Chondrinidae Steenberg, 1925 Goephila Pupilina — Pupilloidea Pleurodiscidae Wenz, 1923 Geophila Helixina Endodontinia Punctoidea Pyramidulidae Wenz, 1923 Geophila Pupillina — Pupilloidea Valloniidae Morse, 1864 Geophila Pupillina — Pupilloidea Strobilopsidae Pilsbry, 1918 Geophila Pupillina — Pupilloidea Partulidae Achatinina Pilsbry, 1900 Geophila Schileyko, 1979 = Partuloidea Enidae (= Buliminidae) Clessin, 1879 Goephila Pupillina — Pupilloidea Clausilidae Mörch, 1864 Geophila Achatinina = Clausilioidea Cerionidae (= Ceriidae) Fleming, 1818 Geophila Pupillina — Cerioidea Dorcasiidae Connolly, 1915 Geophila Achatinina — Achatinoidea Strophocheilidae Thiele, 1926 Geophila Achatinina — Achatinoidea Ferussaciidae Bourguignat, 1883 Geophila Achatinina = Subulinoidea Subulinidae Crosse & Fischer, 1877 Geophila Achatinina — Subulinoidea Spiraxidae Oleacinina Baker, 1955 Geophila Schileyko, 1979 — Testacelloidea Megaspiridae Pilsbry, 1904 Geophila Achatinina — Clausilioidea Achatinidae Swainson, 1840 Geophila « Achatinina — Achatinoidea Streptaxidae Gray, 1840 Geophila Oleacinina — Streptaxoidea Haplotrematidae H.B. Baker, 1925 Geophila Helixina Helixinia Rhytidoidea Systrophiidae Thiele, 1926 Geophila Helixina Endodontinia Punctoidea Rhytididae (= Paraphantidae) Pilsbry, 1893 Geophila Helixina Helixinia Rhytidoidea Aperidae (= Chlamydephoridae) Möllendorff, 1902 = = = = Macrocyclidae Thiele, 1926 = = = = Acavidae Pilsbry, 1895 Geophila Achatinina — Achatinoidea Clavatoridae Thiele, 1926 Geophila Achatinina — Achatinoidea Caryodidae = Thiele, 1926 — == == STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 343 APPENDIX. (Continued) Boss, 1982 Nordsieck, 1985, 1986 Family Suborder Infraorder Superfamily Order Suborder Superfamily Achatinellidae Gulick, 1873 Orthurethra — Achatinellacea Orthurethra — Achatinelloidea Tornatellididae Cooke & Kondo, 1960 Orthurethra — Achatinellacea' Orthurethra — Achatinelloidea' Amastridae Pilsbry, 1911 Orthurethra = Cionellacea Orthurethra — Cochliocopoidea Cionellidae (= Cochliocopidae) Clessin, 1879 Orthurethra — Cionellacea Orthurethra — Cochliocopoidea Pupillidae Turton, 1831 Orthurethra — Pupillacea Orthurethra — Pupilloidea Vertiginidae Fitzinger, 1833 Orthurethra = Pupillacea Orthurethra — Pupilloidea Orculidae Pilsbry, 1918 Orthurethra = Pupillacea? Orthurethra — Pupilloidea Chondrinidae Steenberg, 1925 Orthurethra — Pupillacea? Orthurethra — Pupilloidea Pleurodiscidae Wenz, 1923 Orthurethra — Pupillacea Orthurethra = Pupilloidea Pyramidulidae Wenz, 1923 Orthurethra — Pupillacea? Orthurethra — Pupilloidea Valloniidae Morse, 1864 Orthurethra — Pupillacea Orthurethra a Pupillacea Strobilopsidae Pilsbry, 1918 Orthurethra = Pupillacea Orthurethra — Pupilloidea Partulidae Pilsbry, 1900 Orthurethra — Achatinellacea Sigmurethra Achatinida Partuloidea Enidae (= Buliminidae) Clessin, 1879 Orthurethra — Pupillacea Orthurethra — Buliminoidea Clausiliidae Mörch, 1864 Mesurethra — Clausilacea Orthurethra — Clausilioidea*? Cerionidae (= Ceriidae) Fleming, 1818 Mesurethra — Clausiliacea — = — Dorcasiidae Connolly, 1915 Mesurethra — Strophocheilacea Sigmurethra Achatinida Acavoidea Strophocheilidae Thiele, 1926 Mesurethra = Strophocheilacea Sigmurethra Achatinida Acavoidea Ferussaciidae Bourguignat, 1883 Sigmurethra Holopodopes Strophocheilacea Sigmurethra Achatinida Achatinoidea Subulinidae Crosse & Fischer, 1877 Sigmurethra Holopodopes Achatinacea Sigmurethra Achatinida Achatinoidea Spiraxidae Baker, 1955 Sigmurethra Holopodopes Achatinacea Sigmurethra Achatinida Oleacinoidea Megaspiridae Pilsbry, 1904 Mesurethra — Clausiliacea Sigmurethra Achatinida Orthalicoidea? Achatinidae Swainson, 1840 Sigmurethra Holopodopes Achatinacea Sigmurethra Achatinida Achatinoidea Streptaxidae Gray, 1840 Sigmurethra Holopodopes Streptaxacea Sigmurethra Achatinida Streptaxoidea Haplotrematidae H.B. Baker, 1925 Sigmurethra Holopodopes Rhytidacea Sigmurethra Achatinida Rhytidoidea Systrophiidae Thiele, 1926 Sigmurethra Aulacopoda Limacacea Sigmurethra Achatinida Rhytidoidea Rhytididae (= Paraphantidae) Pilsbry, 1893 Sigmurethra Holopodopes Rhytidacea Sigmurethra Achatinida Rhytidoidea Aperidae (= Chlamydephoridae) Möllendorff, 1902 Sigmurethra Holopodopes Rhytidacea — = = Macrocyclidae : Thiele, 1926 Sigmurethra Holopodopes Rhytidacea Sigmurethra Achatinida Acavoidea'® Acavidae Pilsbry, 1895 Sigmurethra Holopodopes Rhytidacea Sigmurethra Achatinida Acavoidea Clavatoridae Thiele, 1926 = — == = == =a Caryodidae Thiele, 1926 — — — Sigmurethra Achatinida Acavoidea (continued) 344 APPENDIX. (Continued) EMBERTON ET AL. Family Achatinellidae Gulick, 1873 Tornatellididae Cooke & Kondo, 1960 Amastridae Pilsbry, 1911 Cionellidae (= Cochliocopidae) Clessin, 1879 Pupillidae Turton, 1831 Vertiginidae Fitzinger, 1833 Orculidae Pilsbry, 1918 Chondrinidae Steenberg, 1925 Pleurodiscidae Wenz, 1923 Pyramidulidae Wenz, 1923 Valloniidae Morse, 1864 Strobilopsidae Pilsbry, 1918 Partulidae Pilsbry, 1900 Enidae (= Buliminidae) Clessin, 1879 Clausiliidae Mörch, 1864 Cerionidae (= Ceriidae) Fleming, 1818 Dorcasiidae Connolly, 1915 Strophocheilidae Thiele, 1926 Ferussaciidae Bourguignat, 1883 Subulinidae Crosse & Fischer, 1877 Spiraxidae Baker, 1955 Megaspiridae Pilsbry, 1904 Achatinidae Swainson, 1840 Streptaxidae Gray, 1840 Haplotrematidae H.B. Baker, 1925 Systrophiidae Thiele, 1926 Rhytididae (= Paraphantidae) Pilsbry, 1893 Aperidae (= Chlamydephoridae) Mollendorff, 1902 Macrocyclidae Thiele, 1926 Acavidae Pilsbry, 1895 Clavatoridae Thiele, 1926 Caryodidae Thiele, 1926 Suborder Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Orthurethra Brachynephra Brachynephra Dolichonephra Dolichonephra Dolichonephra Brachynephra ‚ Dolichonephra Dolichonephra Dolichonephra Brachynephra Brachynephra Brachynephra Tillier, 1989 Superfamily Pupilloidea Pupilloidea' Chondrinoidea Chondrionidea Pupilloidea Chondrinoidea Chondrinoidea Chondrinoidea Pupilloidea Pupilloidea Pupilloidea'® Partuloidea Partuloidea Clausilioidea Clausilioidea Achatinoidea Achatinoidea Achatinoidea?° Clausiliodea Achatinoidea Achatinoidea Helicoidea Endodontoidea Acavoidea Acavoidea STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 345 APPENDIX. (Continued) Family Urocoptidae Pilsbry & Vanatta, 1898 Bulimulidae Tryon, 1867 Orthalicidae Albers-Martens, 1860 Amphibulimidae Crosse & Fischer, 1873 Odontostomidae Pilsbry & Vanatta, 1898 Punctidae Morse, 1864 Endodontidae Pilsbry, 1894 Charopidae Hutton, 1884 Otoconchidae Cockerell, 1893 Helicodiscidae Pilsbry, 1927 Discidae Thiele, 1931 Arionidae Gray, 1840 Philomycidae Gray, 1847 Succineidae Beck, 1837 Athoracophoridae Fischer, 1883 Helicarionidae Bourguignat, 1888 Euconulidae H.B. Baker, 1928 Ariophantidae Godwin-Austen, 1888 Urocyclidae Simroth, 1889 Aillyidae H.B. Baker, 1930 Zonitidae Mörch, 1864 Trochomorphidae Möllendorff, 1890 Vitrinidae Fitzinger, 1833 Thyrophorellidae Girard, 1895 Parmacellidae Gray, 1860 Limacidae Rafinesque, 1815 Milacidae Germain, 1930 Trigonochlamydidae Hesse, 1882 Testacellidae Gray, 1840 Polygyridae (= Mesodontidae) Pilsbry, 1894 Sagdidae Pilsbry, 1895 Corillidae (= Plectopylidae) Pilsbry, 1905 Oleacinidae Adams, 1855 Camaenidae Pilsbry, 1894 Ammonitellidae Pilsbry, 1930 Solem, 1978 Order Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmuerthra Sigmurethra Sigmurethra Sigmuretha Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Sigmurethra Suborder Superfamily Holopodopes Holopodopes Holopodopes Holopodopes Holopodopes Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Aulacopoda Holopoda Holopoda Holopoda Holopoda Holopoda Holopoda Bulimulacea Bulimulacea Bulimulacea? Bulimulacea? Bulimulacea? Arionacea Arionacea Arionacea Arionacea® Arionacea Arionacea Arionacea Arionacea Succineacea Succineacea? Limacacea A Limacacea A’ Limacacea A’ Limacacea A Limacacea A Limacacea B Limacacea B® Limacacea B® Limacacea B? Limacacea B Limacacea B Limacacea B° Limacacea B Limacacea B? Polygyracea Polygyracea Polygyracea Oleacinacea? Camaenacea Camaenacea (continued) 346 APPENDIX. (Continued) EMBERTON ET AL. Family Order Urocoptidae Pilsbry & Vanatta, 1898 Geophila Bulimulidae Tryon, 1867 Geophila Orthalicidae Albers-Martens, 1860 = Amphibulimidae Crosse & Fischer, 1873 Geophila Odontostomidae Pilsbry & Vanatta, 1898 Geophila Punctidae Morse, 1864 Geophila Endodontidae Pilsbry, 1894 Geophila Charopidae Hutton, 1884 = Otoconchidae Cockerell, 1893 Geophila Helicodiscidae Pilsbry, 1927 Geophila Discidae Thiele, 1931 = Arionidae Gray, 1840 Geophila Philomycidae Gray, 1847 Geophila Succineidae Beck, 1837 Succineida Athoracophoridae Fischer, 1883 Athoracophorida Helicarionidae Bourguignat, 1888 Geophila Euconulidae H.B. Baker, 1928 Geophila Ariophantidae Godwin-Austen, 1888 Geophila Urocyclidae Simroth, 1889 Geophila Aillyidae H.B. Baker, 1930 Aillyida Zonitidae Mörch, 1864 Geophila Trochomorphidae Möllendorff, 1890 Geophila Vitrinidae Fitzinger, 1833 Geophila Thyrophorellidae Girard, 1895 Geophila Parmacellidae Gray, 1860 Geophila Limacidae Rafinesque, 1815 Geophila Milacidae Germain, 1930 Geophila Trigonochlamydidae Hesse, 1882 Geophila Testacellidae Gray, 1840 Geophila Polygyridae (= Mesodontidae) Pilsbry, 1894 Geophila Sagdidae Pilsbry, 1895 Geophila Corillidae ( = Plectopylidae) Pilsbry, 1905 Geophila Oleacinidae Adams, 1855 Geophila Camaenidae Pilsbry, 1894 Geophila Ammonitellidae Pilsbry, 1930 Geophila Suborder Achatinina Achatinina Achatinina Achatinina Helixina Helixina Helixina Helixina Helixinia Helixinia Helixina Helixina Helixina Helixina Helixina Helixina Helixina Helixina Helixina Limaxina Helixina Limaxina Oleacinina Helixina Pupillina Helixina Oleacinina Helixina Helixina Schileyko, 1979 Infraorder Endodontinia Endodontinia Helixinia Endodontinia Helixinia Helixinia Helixinia Helixinia Helixinia Helixinia na Schileyko, 1979 Helixinia Helixinia Endodontinia Zonitinia Limaxinia Zonitinia Trigonochlamydinia Schileyko, 1979 Endodontinia Helixinia Helixinia Helixinia Superfamily Clausilioidea Achatinoidea Achatinoidea Achatinoidea Punctoidea Punctoidea Arionoidea Punctoidea Arionoidea Arionoidea Vitrinoidea Gastrodontoidea Vitrinoidea Vitrinoidea Zonitoidea Vitrinoidea Vitrinoidea Thyrophorelloidea Parmacelloidea Limacoidea Parmacelloidea Trigonochlamydoidea Testacelloidea Punctoidea Sagdoidea Helicoidea Testacelloidea Helicoidea Helicoidea STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 347 APPENDIX. (Continued) Boss, 1982 Nordsieck, 1985, 1986 Family Suborder Infraorder Superfamily Order Suborder Superfamily Urocoptidae Pilsbry & Vanata, 1898 Sigmurethra Holopodopes Bulimulacea — — — Bulimulidae Tyron, 1867 Sigmurethra Holopodopes Bulimulacea Sigmurethra Achatinida Orthalicoidea'* Orthalicidae Albers-Martens, 1860 Sigmurethra Holopodopes Bulimulacea Sigmurethra Achatinida Orthalicoidea Amphibulimidae Crosse 4 Fischer, 1873 Sigmurethra Holopodopes Bulimulacea Sigmurethra Achatinida Orthalicoidea'* Odontostomidae Pilsbry 8 Vanatta, 1898 Sigmurethra Holopodopes Bulimulacea Sigmurethra Achatinida Orthalicoidea'* Punctidae Morse, 1864 Sigmurethra Aulacopoda Arionacea'® Sigmurethra Achatinida Punctoidea Endodontidae Pilsbry, 1894 Sigmurethra Aulacopoda Arionacea Sigmurethra Achatinida Punctoidea Charopidae Hutton, 1884 Sigmurethra Aulacopoda Arionacea'? Sigmurethra Achatinida Punctoidea'’ Otoconchidae Cockerell, 1893 Sigmurethra Aulacopoda Arionacea Sigmurethra Achatinida Punctoidea'’ Helicodiscidae Pilsbry, 1927 Sigmurethra Aulacopoda Апопасеа'° Sigmurethra Achatinida Punctoidea!” Discidae Thiele, 1931 — = — Sigmurethra Achatinida Punctoidea Arionidae Gray, 1840 Sigmurethra Aulacopoda Arionacea Sigmurethra Helicida Arionoidea Philomycidae Gray, 1847 Sigmurethra Aulacopoda Arionacea Sigmurethra Helicida Arionoidea Succineidae Beck, 1837 Heterurethra — — Elasmognatha — Succinoidea Athoracophoridae Fischer, 1883 Heterurethra — = Elasmognatha = Athoracophoroidea Helicarionidae Bourguignat, 1888 Sigmurethra Aulacopoda Limacacea Sigmurethra Helicida Helixarionoidea Euconulidae H.B. Baker, 1928 Sigmurethra Aulacopoda Limacacea'' Sigmurethra Helicida Helixarionoidea Ariophantidae Godwin-Austen, 1888 Sigmurethra Aulacopoda Limacacea'' Sigmurethra Нейсча Helixarionoidea'' Urocyciidae Simroth, 1889 Sigmurethra Aulacopoda Limacacea Sigmurethra Helicida Helixarionoidea Aillyidae H.B. Baker, 1930 Heterurethra — — Sigmurethra Achatinida Aillyoidea Zonitidae Mörch, 1864 Sigmurethra Aulacopoda Limacacea Sigmurethra Helicida Vitrinoidea Trochomorphidae Möllendorff, 1890 Sigmurethra Aulacopoda Limacacea'? Sigmurethra Helicida Helixarionoidea'' Vitrinidae Fitzinger, 1833 Sigmurethra Aulacopoda Limacacea'? Sigmurethra Helicida Vitrinoidea Thyrophorellidae Girard, 1895 Sigmurethra Aulacopoda Arionacea Sigmurethra Achatinida Achatinoidea? Parmacellidae Gray, 1860 — — == Sigmurethra Helicida Vitrinoidea Limacidae Rafinesque, 1815 Sigmurethra Aulacopoda Limacacea Sigmurethra Helicida Limacoidea Milacidae Germain, 1930 = = — Sigmurethra Helicida Vitrinoidea Trigonochlamydidae Hesse, 1882 Sigmurethra Aulacopoda Limacacea Sigmurethra Helicida Trigonochlamydoidea Testacellidae Gray, 1840 Sigmurethra Aulacopoda Testacellacea Sigmurethra Achatinida Oleacinoidea Polygyridae (=Mesodontidae) | Pilsbry, 1894 Sigmurethra Holopoda Polygyracea Sigmurethra Helicida Mesodontoidea Sagdidae Pilsbry, 1895 Sigmurethra Holopoda Oleacinacea Sigmurethra Helicida Sagdoidea Corillidae (= Plectopylidae) Pilsbry, 1905 Sigmurethra Holopoda Polygyracea Sigmurethra Achatinida Plectopyloidea Oleacinidae Adams, 1855 Sigmurethra Holopoda Oleacinacea Sigmurethra Achatinida Oleacinoidea Camaenidae Pilsbry, 1894 Sigmurethra Holopoda Helicacea Sigmurethra Helicida Camaenoidea Ammonitellidae Pilsbry, 1930 Sigmurethra Holopoda Polygyracea Sigmurethra Achatinida Acavoidea'® (continued) 348 APPENDIX. (Continued) EMBERTON ET AL. Family Urocoptidae Pilsbry & Vanatta, 1898 Bulimulidae Tryon, 1867 Orthalicidae Albers-Martens, 1860 Amphibulimidae Crosse & Fischer, 1873 Odontostomidae Pilsbry & Vanatta, 1898 Punctidae Morse, 1864 Endodontidae Pilsbry, 1894 Charopidae Hutton, 1884 Otoconchidae Cockerell, 1893 Helicodiscidae Pilsbry, 1927 Discidae Thiele, 1931 Arionidae Gray, 1840 Philomycidae Gray, 1847 Succineidae Beck, 1837 Athoracophoridae Fischer, 1883 Helicarionidae Bourguignat, 1888 Euconulidae H.B. Baker, 1928 Ariophantidae Godwin-Austen, 1888 Urocyclidae Simroth, 1889 Aillyidae H.B. Baker, 1930 Zonitidae Mörch, 1864 Trochomorphidae Möllendorff, 1890 Vitrinidae Fitzinger, 1833 Thyrophorellidae Girard, 1895 Parmacellidae Gray, 1860 Limacidae Rafinesque, 1815 Milacidae Germain, 1930 Trigonochlamydidae Hesse, 1882 Testacellidae Gray, 1840 Polygyridae (= Mesodontidae) Pilsbry, 1894 Sagdidae Pilsbry, 1895 Corillidae ( = Plectopylidae) Pilsbry, 1905 Oleacinidae Adams, 1855 Camaenidae Pilsbry, 1894 Ammonitellidae Pisbry, 1930 Suborder Brachynephra Brachynephra Brachynephra Brachynephra Brachynephra Dolichonephra Dolichonephra Dolichonephra Dolichonephra Brachynephra Dolichonephra Dolichonephra Dolichonephra Dolichonephra Tillier, 1989 Dolichonephra Dolichonephra Dolichonephra Dolichonephra Dolichonephra Dolichonephra Dolichonephra Dolichonephra Dolichonephra Brachynephra Dolichonephra Dolichonephra Brachynephra Superfamily Clausilioidea Clausiloidea Endodontoidea Endodontoidea Endodontoidea Zonitoidea Zonitoidea Zonitoidea'? Achatinoidea Endodontoidea Helicoidea Zonitoidea Helicoidea'" Zonitoidea Zonitoidea Helicoidea Zonitoidea Zonitoidea Zonitoidea Zonitoidea Achatinoidea?° Helicoidea Helicoidea Acavoidea Achatinoidea Helicoidea Acavoidea”' STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 349 APPENDIX. (Continued) Family Oreohelicidae Pilsbry, 1939 Bradybaenidae Pilsbry, 1939 Helminthoglyptidae (= Xanthonychidae) Pilsbry, 1939 Helicidae Rafinesque, 1815 Megalobulimidae (in Strophocheilidae) Leme, 1973 Anadromidae Zilch, 1959 (fossil) Stenogyridae (in Subulinidae?) Wenz, 1923 (fossil) Filholiidae Wenz, 1923 Dendropupidae Wenz, 1938 Thysanophoridae (in Polygyridae?) Pilsbry, 1926 Gastrodontidae (in Zonitidae) Tryon, 1866 Chlamydephoridae (= Aperidae) Cockerell, 1935 Sphincterochilidae (in Helicidae) Zilch, 1959 Helicodontidae (in Helicidae) Hesse, 1918 Humboldianidae (in Helminthoglyptidae) Pilsbry, 1939 Hygromiidae (in Helicidae) Tryon, 1866 Daudebardiidae (in Zonitidae) Pilsbry, 1908 Boetgerillidae (in Parmacellidae) Van Goethem, 1972 Agriolimacidae (in Limacidae) Wagner, 1935 Helicellidae (in Helicidae) Wenz, 1923 Cerastuidae (in Enidae) Wenz, 1923 Coeliaxidae (in Subulindidae) Pilsbry, 1907 Megomphicidae (in Ammonitellidae) H.B. Baker, 1930 Sculptariidae (in Corillidae) Nordsieck, 1986? Oopeltidae (in Arionidae) H.B. Baker, 1930 Cystopeltidae (in Ariophantidae) Cockerell, 1891 Solaropsidae (in Camaenidae) Nordsieck, 1986 Order Sigmurethra Sigmurethra Sigmurethra Sigmurethra Solem, 1978 Suborder Superfamily Holopoda Camaenacea Holopoda Helicacea Holopoda Helicacea Holopoda Helicacea (continued) 350 APPENDIX. (Continued) EMBERTON ET AL. Family Order Oreohelicidae Pilsbry, 1939 Geophila Bradybaenidae Pilsbry, 1939 Geophila Helminthoglyptidae (= Xanthonychidae) Pilsbry, 1939 Geophila Helicidae Rafinesque, 1815 Geophila Megalobulimidae (in Strophocheilidae) Geophila Leme, 1973 Ferussac, 1812 Anadromidae Zilch, 1959 (fossil) Geophila Stenogyridae (in Subulinidae?) Wenz, 1923 (fossil) Geophila Filholiidae Wenz, 1923 Geophila Dendropupidae Wenz, 1938 Geophila Thysanophoridae (in Polygyridae?) Pilsbry, 1926 Geophila Gastrodontidae (in Zonitidae) Tryon, 1866 Geophila Chlamydephoridae ( = Aperidae) Cockerell, 1935 Geophila Sphincterochilidae (in Helicidae) Zilch, 1959 Geophila Helicodontidae (in Helicidae) Hesse, 1918 Geophila Humboldianidae (in Helminthoglyptidae) Pilsbry, 1939 Geophila Hygromiidae (in Helicidae) Tryon, 1866 Geophila Daudebardiidae (in Zonitidae) Pilsbry, 1908 Geophila Boetgerillidae (in Parmacellidae) Van Goethem, 1972 Geophila Agriolimacidae (in Limacidae) Wagner, 1935 Geophila Helicellidae (in Helicidae) Wenz, 1923 Cerastuidae (in Enidae) Wenz, 1923 Coeliaxidae (in Subulindidae) Pilsbry, 1907 Megomphicidae (in Ammonitellidae) H.B. Baker, 1930 Sculptariidae (in Corillidae) Nordsieck, 1986? Oopeltidae (in Arionidae) H.B. Baker, 1930 Cystopeltidae (in Ariophantidae) Cockerell, 1891 Solaropsidae (in Camaenidae) Nordsieck, 1986 Schileyko, 1979 Suborder Helixina Helixina Helixina Helixina Achatinina Schileyko, 1979 Achatinina Achatinina Achatinina Pupillina Pupillina Helixina Helixina Helixinia Helixina Helixina Helixina Helixina Limaxina Limaxina Infraorder Helixinia Helixinia Helixinia Helixinia Helixinia Helixinia Helixinia Helixinia Helixinia Helixinia Zonitinia Limaxinia Schieyko, 1979 Limaxinia Superfamily Helicoidea Helicoidea Helicoidea Helicoidea Achatinoidea Achatinoidea Subulinoidea Clausilioidea Achatinelloidea Sagdoidea Gastrodontoidea Rhytidoidea Sphincterochiloidea Helicodontoidea Helicoidea Hygromiodea Zonitoidea Limacoidea Limacoidea STYLOMMATOPHORAN CLASSIFICATIONS AND LRRNA EVALUATION 351 APPENDIX. (Continued) Family Oreochelicidae Pilsbry, 1939 Bradybaenidae Pilsbry, 1939 Helminthoglyptidae (= Xanthonychidae) Pilsbry, 1939 Helicidae Rafinesque, 1815 Megalobulimidae (in Strophocheilidae) Leme, 1973 Anadromidae Zilch, 1959 (fossil) Stenogyridae (in Subulinidae?) Wenz, 1923 (fossil) Filholiidae Wenz, 1923 Dendropupidae Wenz, 1938 Thysanophoridae (in Polygyridae?) Pilsbry, 1926 Gastrodontidae (in Zonitidae) Tryon, 1866 Chlamydephoridae (= Aperidae) Cockerell, 1935 Sphincterochilidae (in Helicidae) Zilch, 1959 Helicodontidae (in Helicidae) Hesse, 1918 Humboldianidae (in Helminthoglyptidae) Pilsbry, 1939 Hygromiidae (in Helicidae) Tryon, 1866 Daudebardidae (in Zonitidae) Pilsbry, 1908 Boetgerillidae (in Parmacellidae) Van Goethem, 1972 Agriolimacidae (in Limacidae) Wagner, 1935 Helicellidae (in Helicidae) Wenz, 1923 Cerastuidae (in Enidae) Wenz, 1923 Coeliaxidae (in Subulindidae) Pilsbry, 1907 Megomphicidae (in Ammonitellidae) H.B. Baker, 1930 Sculptariidae (in Corillidae) Nordsieck, 1986? Oopeltidae (in Arionidae) H.B. Baker, 1930 Cystopeltidae (in Ariophantidae) Cockerell, 1891 Solaropsidae (in Camaenidae) Nordsieck, 1986 Boss, 1982 Nordsieck, 1985, 1986 Suborder Infrarder Superfamily Order Suborder Superfamily Sigmurethra Holopoda Helicacea Sigmurethra Achatinida Punctoidea Sigmurethra Holopoda Helicacea Sigmurethra Helicida Helicoidea Sigmurethra Holopoda Helicacea Sigmurethra Helicida Helicoidea Sigmurethra Holopoda Helicacea Sigmurethra Helicida Helicoidea Sigmurethra Holopoda Polygyracea Sigmurethra Aulacopoda Итасасеа"? Sigmurethra Aulacopoda Helicacea Sigmurethra Helicida Mesodontoidea Sigmurethra Helicida Gastrodontoidea Sigmurethra Achatinida Rhytidoidea Sigmurethra Helicida Helicoidea Sigmuretha Helicida Helicoidea Sigmurethra Helicida Vitrinoidea Sigmurethra Helicida Limacoidea Sigmurethra Helicida Limacoidea Orthurethra — Buliminoidea Sigmurethra Achatinida Achatinoidea Sigmurethra Achatinida Acavoidea Sigmurethra Achatinida Plectopyloidea Sigmurethra Achatinida Punctoidea Sigmurethra Helicida Helixarionoidea Camaenoidea (continued) Sigmurethra Helicida 352 EMBERTON ET AL. APPENDIX. (Continued) Tillier, 1989 Family Suborder Superfamily Oreohelicidae Pilsbry, 1939 Brachynephra Acavoidea Bradybaenidae Pilsbry, 1939 Dolichonephra Helicoidea Helminthoglyptidae (= Xanthonychidae) Pilsbry, 1939 Dolichonephra Helicoidea Helicidae Rafinesque, 1815 Dolichonephra Helicoidea Megalobulimidae (in Strophocheilidae) Leme, 1973 = — Anadromidae Zilch, 1959 (fossil) — — Stenogyridae (in Subulinidae?) (fossil) Wenz, 1923 = — Filholidae Wenz, 1923 = — Dendropupidae Wenz, 1923 = — Thysanophoridae (in Polygridae?) Pilsbry, 1926 — — Gastrodontidae (in Zonitidae) Tryon, 1866 — = Chlamydephoridae ( = Aperidae) Cockerell, 1935 Brachynephra Acavoidea?? Sphincterochilidae (in Helicidae) Zilch, 1959 — — Helicodontidae (in Helicidae) Hesse, 1918 — — Humboldianidae (in Helminthoglyptidae) Pilsbry, 1939 = = Hygromiidae (in Helicidae) Tryon, 1866 — = Daudebardiidae (in Zonitidae) Pilsbry, 1908 = = Boetgerillidae (in Parmacellidae) Van Goethem, 1972 = = Agriolimacidae (in Limacidae) Wagner, 1935 = = Helicellidae (in Helicidae) . Wenz, 1923 = == Cerastuidae (in Enidae) Wenz, 1923 = = Coeliaxidae (in Subulindidae) Pilsbry, 1907 = = Megomphicidae (in Ammonitellidae) H.B. Baker, 1930 — = Sculptariidae (in Corillidae) Nordsieck, 1986? — — Oopeltidae (in Arionidae) H.B. Baker, 1930 — = Cystopeltidae (in Ariophantidae) Cockerell, 1891 — = Solaropsidae (in Camaenidae) = Nordsieck, 1986 = 'Synonymized under Achatinellidae.; *Synonymized under Pupillidae. ; 3Synonymized under Pleurodiscidae.; *Synonymized under Acavidae.; °Synonymized under Bulimulidae.; *Synonymized under Charopidae.; “Synonymized under Helicarionidae.; ®Synonymized under Zonitidae.; 9Synonymized under Limacidae.; '"Synonymized under Endodontidae.; '' Synonymized under Helicarionidae.; '*Synonymized under Zonitidae.; '"Occupies an isolated position in the order, so may be a separate suborder.; **Synonymized under Orthalicidae.; '*Synonymized under Caryodidae.; '*Synonymized under Megomphicidae.; '"Synonymized under Punctidae.; '*Synonymized under Valloniidae.; '*Synonymized under Arionidae.; °°Synonymized under Oleacinidae.; ?'Synonymized under Oreohelicidae.; Synonymized under Rhytididae. MALACOLOGIA, 1990, 31(2): 353-362 ASPECTS OF THE LIFE CYCLE, POPULATION DYNAMICS, GROWTH AND SECONDARY PRODUCTION OF THE SNAIL MONACHA CARTUSIANA (MULLER, 1774) (GASTROPODA PULMONATA) IN GREECE A. Staikou & M. Lazaridou-Dimitriadou Section of Zoology, Department of Biology, University of Thessaloniki, 54006 Thessaloniki, Greece ABSTRACT The life cycle, population dynamics, growth and secondary production of the land snail Mo- nacha cartusiana were studied in northern Greece. Demographic analysis of the populations of M. cartusiana revealed that (a) two to three cohorts existed in the field throughout the year, (b) the reproductive period started in the beginning, middle or end of autumn, depending on the weather conditions, and (с) growth of пему hatched individuals was also influenced by weather conditions. Net reproductive rate (Ro) was equal to 2.07, and the finite capacity for increase (г.) was equal to 1. Estimated annual secondary production with the Hynes’ size frequency method revealed a mean standing crop (В) of 0.147 g/m?/year and a production (P) of 0.31 + 0.02 g/m?/year. Annual turnover ratio (Р/В) was equal to 2.11. INTRODUCTION Several species of the helicid snail Mo- nacha are known to exist in Greece. Pinter (1978) described the systematics and distri- bution of three Greek Monacha species: M. messenica, M. dirphica and M. beieri. Although Monacha cartusiana is wide- spread in Europe (Germain, 1930), little is known about its life history (Taylor, 1921; Ger- main, 1930; Chatfield, 1968). M. cartusiana was studied in a natural hab- itat, where it coexists with three other helicid species, namely Helix lucorum, Bradybaena fruticum and Cepaea vindobonensis, the ecology of which has also been studied (Staikou et al., 1988; Staikou & Lazaridou- Dimitriadou, in press). The relationships of these coexisting species are important for two reasons: in culturing H. lucorum, the most im- portant of the edible Greek species, in open enclosures, and in order to study their possi- ble competitive strategies. So in this paper the biology, ecology, relative growth and the annual secondary production of M. cartusiana are studied. Study Area The habitat of M. cartusiana was situated in the Logos region of Edessa (N. Greece), which lies 100 km from Thessaloniki. The 353 study on the ecology and biology of the edible snail Helix lucorum, which was carried out in the same region, had made it necessary to fence off the study area to prevent local peo- ple collecting Helix lucorum. A full description ofthe study area and the main characteristics of the coexisting snail species have been given in a previous paper (Staikou et al., 1988). The vegetation was not uniform but had patches where different plant species dominated. The climate of the region is of the humid mediterranean type, characterised by prolonged rainy periods in mid-summer (Staikou et al., 1988). METHODS AND MATERIALS The study of M. cartusiana started in June 1982 and lasted four years. Data from May 1983 to December 1985 were used for the demographic analysis of the populations. Samples were taken randomly every 15 days throughout the year. The quadrat sam- ple-size used (50 x 50 ст?) was determined by Healys method (Cancela da Fonseca, 1965). Elliot's method (1971) was used to de- termine the necessary total number of sam- pling units for a sampling error less than 20%. Sampling was carried out during morning hours in the absence of rain. All snails found in a quadrat were collected, measured and 354 STAIKOU & LAZARIDOU-DIMITRIADOU then returned to their initial places. The larg- est diameter of the shell (D) and the peris- tome diameter (d) were measured. Spatial distribution of the snails in the hab- itat was examined by using Taylors power law (1961). The parameter b from Taylors equation s* = ах? (where a=constant, $° = variance, X = mean number of snails found in a sample unit) was used as an index of dis- persion. Parameter b is fairly constant and characterizes a species (Southwood, 1966); it is independent of the total number of samples and the total number of animals in the sam- ples; it depends only on the quadrat size (El- liot, 1971). The class interval of the monthly size fre- quency histograms was 1 mm (Fig. 1) and was determined by Goulden’s method (Сап- cela da Fonseca, 1965). The largest diameter of the shell (D) was used for the construction of the histograms because it is generally ac- cepted as the most reliable morphometric pa- rameter (Lazaridou-Dimitriadou, 1978; Char- rier & Daguzan, 1978; Daguzan, 1982). The cohorts were discriminated using prob- ability paper (Harding, 1949). This method was valid because the modes of the age classes were separated by at least 2.5 stan- dard deviations (Grant, 1989), except in Oc- tober and November 1983 and September and November 1984. Although many age classes had less than 50 individuals, the modal values are consistent from month to month (Fig. 2), which confirms that the modes are real and not the result of sampling varia- tion. This method has been used for demo- graphic analyses of the populations of other molluscs (Hugues, 1970; Levèque, 1972; Da- guzan, 1975; Lazaridou-Dimitriadou, 1978, 1981; Lazaridou-Dimitriadou & Kattoulas, 1985; Staikou et al., 1988). An age-specific life table was constructed based on the fate of areal cohort that entered the population in 1983 (Fig. 2). The method- ology for the construction of the life table is described in detail by Staikou et al. (1988). To determine the total number of snails hatched in 1983, the method of Richards and Waloff (Southwood, 1966) was used. The number of snails of the 1983 cohort in the following years was extrapolated from the results of the demographic analyses of the populations of M. cartusiana. Mayrat's method (1965a,b) was used to distinguish between juveniles and adults by comparing the growth of the largest shell diameter (D) relative to the dry weight of the snail (W) and to the peristome diameter (d). To determine annual production, the snails were grouped into 15 size classes. The mean number of snails (n) in each size class was determined using data from the population dynamics. To determine dry body and shell weight, 63 snails representing all size classes were used following the methodology de- scribed in detail in Staikou et al. (1988). An- nual production in 1984 was calculated by the Hyne's size frequency method modified ac- cording to Benke (1979) and Krueger & Mar- tin (1980). This has the advantage that single cohorts within the data need not be identified to calculate production, although it may pro- duce an overestimate (Waters & Crawford, 1973). The formulae used were given by Staikou et al. (1988). RESULTS A. Aspects of the Biology Individuals were sexually mature when the largest shell diameter (D) exceeds 7 mm. Sexual maturity is indicated externally by the presence of a characteristic reddish strip near the edge of the aperture and the formation of an internal lip. During the breeding season, all snails with D > 9 mm showed these external characteristics. Examination of the external features of the shell and the genitalia of 48 snails (7.15 mm < D < 14.25 mm) showed that genitalia were fully formed only when the red ribbon appeared around the aperture. Go- nad maturation was histologically checked in 36 snails collected in June with 3.5 mm 9 mm. Sexual maturity was normally attained two years after hatching. However, about 14% reached maturity one year after hatching; these snails laid eggs one year after hatching and died immediately after (Fig. 2). The re- productive period started at the beginning or inthe middle of autumn, and it was often pro- longed until the start of winter (December ог January). In 1984, some snails laid eggs in late August as well as in late October. The snails were active during winter. They aesti- vated in summer under dry, creeping vegeta- tion or in the ground at surface level, forming ECOLOGY OF MONACHA CARTUSIANA 355 20-5-83 29-1-84 28-9-84 167 o, 321% 167. 247, 29-5-85 8 16 8 8 0 0 1 7 14 1 7 15 22-6-83 26-6-85 @ 1 7 11 1 7 13 16 21-7-83 32 19-3-84 16 24-11-84 48 26-7-85 — Я — un > со | | — > = | > со | | [о oN N | | 1 7 ie” at 7 а 7 13 4 7 14 247% 24-8-83 167% 24-4- 247 y 20-12-84 327 y 26-8-85 16 16 8 16 8 8 0 0 0 0 1 7, 14 1 7 14 1 7 2 4 7 15 24 28-9-83 16 21-5-84 24 20-1-85 24 27-9-85 pl = эх = — Y — Un 32 9-10-85 — > a | | pl Я — un 29-11-85 0 327 y 29-12-83 16r, Ÿ 28-8-84 247% 18-485 æ 20-12-85 16 16 8 Е 0 0 0 0 FIG. 1. Size frequency histograms of the populations of Monacha cartusiana at Edessa (N. Greece) from May 1983 to December 1985 (arrows represent the beginning of the reproductive period). — > era = (a SE — Я Di un — © a Di | — i) pl — =" un — | nt Uy — SI mh Un 356 STAIKOU & LAZARIDOU-DIMITRIADOU TABLE |. Monacha cartusiana population density in the study area from Мау 1983 to December 1985 (п: number of samples; x: mean number of animals / mí; s: standard deviation). 1984 Feb. March April May June 8.72 6.52 2.80 9.44 10.68 8.56 11.56 6.60 6.04 11.76 12.04 9.60 10.36 15.28 70 70 70 70 70 70 70 8.96 9.88 16% 12% 25% 15% 13% 13% 14% 18% 1985 March April May June July 1983 May 83 June July Aug. Sept. Oct. Nov. Dec. Jan. n 48 50 70 OO 70 x 21.25 656 5 2006/7805 e 5 17.36 760 7.64 8.78 20.68 12.56 Sampling error D 11% 16% 17% 15% 15% 13% 1984 July Aug. Sept. Oct. Nov. Dec. Jan. Feb. n 70 70 LOO 70 70 5.12 540 3.60 5.24 5.36 10.04 P- _@ [пут . wj(mg)] (nj-nj + 1)(Gj) (М. wj)°° (mg.m ?) [mg.m ?) 0.34 0.027 0.0881 We 0.259 — 0.878 2.5] 1.265 = 025115 4.58 Salzal 0.625 CMS 4.619 2.121 11.83 4.959 0.225 16.73 6.677 —2.664 23.24 12721 VA 30.74 21.022 0.1021 39.69 27135 10.129 50.65 23.402 8.824 6337 19.712 9.973 TING 13.156 7.879 93.11 7.295 6.468 102.00 1.666 1.667 147.1 41.06 Р = аР’ : 365 / CPI = 15 : 41.06: 365/730 = 308.25 (mg/m2) = 0.31 (g/m2) U(P) = Unj(Gj — G(j — 1))° : 22 - (365/CPI)2 = (3.93 : 10 *) : (365 / 730)? = 0.000098 Confidence interval of P = P + 2[Ц(Р):] = 0.31 + 0.02 PIB r= 10531 0147 ЕЕ adou, 1981; Lazaridou-Dimitriadou & Kattou- las, 1985). In the same biotope B. fruticum showed increased growth rate in spring and in autumn, while H. lucorum like M. cartusiana increased growth rate only in spring (Staikou et al., 1988). High mortality after the reproductive period is common among those helicid snails which are also r-strategists. R, is greater than unity, showing the tendency of the population to in- crease. The reproductive success of M. car- tusiana may be related to its lifespan, which is much shorter than that of such species as H. pomatia (Pollard & Welch, 1980; Lomnicki, 1971) and H. lucorum (Staikou et al., 1988). However, it must be noted that B. fruticum in the same biotope (Staikou & Lazaridou-Dim- itriadou, 1990) and E. vermiculata in similar biotopes (Lazaridou-Dimitriadou & Kattoulas, submitted), have a higher reproductive suc- cesses (Ro= 3.15 and 3.43 respectively) al- though they have a longer life span than M. cartusiana. The value of the annual turnover ratio P/B, which seems to be related to the life span of the species (Russell-Hunter & Buck- ley, 1983; Lamotte & Stern, 1987), was simi- lar to that found for E. vermiculata (P/B= 2.00) (Lazaridou-Dimitriadou & Kattoulas, submitted), which has the same CPI but a longer life span. M. cartusiana has a lower P/B that B. fruticum (P/B= 2.37) from the same biotope, the same CPI, but a longer life span (Staikou & Lazaridou-Dimitriadou, 1990). Finally, the fact that internal changes in genitalia and maturation of the gonad of this species correspond to external morphometric changes of the shell is in agreement with the results reported for such other helicids as E. vermiculata, H. aspersa (Lazaridou-Dimi- triadou & Kattoulas, 1981), Cernuella virgata and Xeropicta arenosa (Lazaridou-Dimitria- dou, 1986) and H. lucorum (Staikou et al., 1988) in Greece and elsewhere as in H. as- persa (Charrier & Daguzan, 1978) and other Helicidae (Yom-Tov, 1971; Bonavita, 1972; Williamson, 1976). ACKNOWLEDGEMENTS Thanks are extended to K. Asmi for her technical assistance. We would like to thank Drs. S.E.R. Bailey and L.M. Cook for their comments in the manuscript. Financial sup- port was provided by the Minister of Agricul- ture. 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BUCKLEY, 1983, Actuarial bioenergetics of nonmarine mol- luscan productivity, In The Mollusca 6, 463—503 ed. RUSSELL-HUNTER, W.D. Academic Press, Ines МУ. SOUTHWOOD, Т. В. E., 1966, Ecological meth- ods. Chapman and Hall. London. STAIKOU, A., LAZARIDOU-DIMITRIADOU, M. & N. FARMAKIS, 1988, Aspects of the life cycle, population dynamics, growth and secondary pro- duction of the edible snail Helix lucorum Lin- naeus 1758 (Gastropoda Pulmonata) in Greece. The Journal of Molluscan Studies, 54: 139—155. 362 STAIKOU & LAZARIDOU-DIMITRIADOU STAIKOU, A. & M. LAZARIDOU-DIMITRIADOU, 1990. The life cycle, population dynamics, growth and secondary production of the snail Brady- baena (B.) fruticum (Müller, 1774) (Gastropoda Pulmonata) in Northern Greece. The Journal of Molluscan Studies, 55. TAYLOR. J. W., 1921, Monograph of the land and freshwater Mollusca of the British Isles. Leeds. TAYLOR. L. R., 1961, Aggregation, variance and the mean. Nature, London 189: 732-735. WATERS. Т. Е. & ©. W. CRAWFORD, 1973, An- nual production of a stream mayfly population: A comparison of methods. Limnology and Ocean- ography, 18: 286-296. WILLIAMSON, P., 1976, Size-weight relationship and field growth rates of the land snail Cepaea nemoralis L. Journal of Animal Ecology, 45: 875— 885. YOM-TOV, Y., 1971, The biology of two desert snails Trochoidea (Xerocrassa) sectzeni and Sphincterochila boisseiri. Israel Journal of Zool- ogy, 20: 231-248. Revised Ms. accepted 1 December 1989 MALACOLOGIA, 1990, 31(2): 363-370 CALYPTOGENA (CALYPTOGENA) BIRMANI, ANEW SPECIES OF VESICOMYIDAE (MOLLUSCA-BIVALVIA) FROM BRAZIL Osmar Domaneschi & Sönia G. B. C. Lopes Departamento de Zoologia, Instituto de Biociéncias, Universidade de Sao Paulo, Cx.Postal 20.520, EP 01498, Sao Paulo, Brazil ABSTRACT Calyptogena (Calyptogena) birmani, a new species of a rare deep-sea family, Vesicomyidae, is described from material collected at a depth of 400 m off the State of Parana, southwest Atlantic Ocean, Brazilian coast, by the R/V W. BESNARD. No living specimens were obtained, and only the shell characters were compared with the known Calyptogena species from the Atlantic and with the most closely related species from the Pacific. Key words: bivalve, Vesicomyidae, Calyptogena, systematics, Brazil. INTRODUCTION During the 2—4 October 1978, the R/V W. BESNARD, of the Instituto Oceanografico, Universidade de Sao Paulo, collected off the coast of Sao Paulo and Parana states, Brazil, in the southwest Atlantic Ocean, a number of shallow to deep-water samples, using a Camp- bell Photo-Grab. At station 2 in a depth of 400 m, 14 empty shells (entire specimens with both valves), 87 left valves and 93 right valves were obtained of an unusually small veneroid- shaped bivalve. Based on careful examina- tion and comparison of this material with the published literature, the specimens were found to be a new species referable to Vesi- comyidae Dall & Simpson, 1901. The Vesi- comyidae were not known irom Brazil until 1975 (Lange de Morretes, 1949, 1954; Rios, 1970, 1975). In a preliminary study, Birman & Lopes (1985) suggested that the R/V W. BE- SNARD material belonged to Calyptogena Dall, 1891, and considered it the first occur- rence of the Vesicomyidae along the Brazilian coast. On this basis, Rios (1985) updated his catalogue. A more accurate review of the pa- pers related to Vesicomyidae revealed that Dall (1889) had already described Callocardia albida from off Rio de Janeiro, at a depth of 108 m, and had placed it in the Isocardiidae; later, Keen (1969) allocated it to the Vesico- myidae. The taxa grouped under Vesicomyidae have had a confused history as discussed by Boss (1968, 1969, 1970), Boss & Turner (1980) and Turner (1985). The lack of a sat- 363 isfactory diagnosis that would exclude them from all other related heterodonts has led var- ious authors to assign these taxa to such fam- ilies as the Arcticidae (= Cyprinidae), Carditi- dae, Kelliellidae and Veneridae (Boss & Turner, 1980). It is beyond the scope of this paper to discuss the systematics of the group. Most authors, following Keen (1969) and Boss & Turner (1980), have considered Ca- lyptogena to belong to the Vesicomyidae. Vesicomyidae is a rare deep-sea family whose living species examined to date come from sulfide-rich substrates (Turner, 1985). The discovery of deep-sea hydrothermal vents on the eastern Pacific sea floor and deep sulfide seeps in the Gulf of Mexico has attracted the attention of zoologists to their abundant macrofauna of which Vesicomyidae was found to be one of the major components (Turner, 1985). Besides bacterial chemosyn- thetic activity, which provides the major bulk of the food supply for the vent and seep com- munities (Turner & Lutz, 1984), a symbiotic association of these bacteria with clams, mussels, tube worms, plays an important role in their nutrition and distribution (Cavanaugh, 1983), and in the food chain dynamics at the vents and seeps (Turner & Lutz, 1984). Vesi- comyidae are also known from reducing sed- iments not related to vents or seeps, as is the case of Calyptogena (Ectenagena) australis Stuardo & Valdovinos, 1988, from off the coast of central Chile (Stuardo & Valdovinos, 1988). All living species of Vesicomyidae known to date shelter chemoautotrophic symbiotic bac- 364 DOMANESCHI & LOPES teria in their large and thick gills (Turner, 1985; Stuardo & Valdovinos, 1988). Based on this fact and on shell characters, Turner (1985) suggested the origin of the large spe- cies of Vesicomyidae, found at the vents and seeps, from small, infaunal deep-sea kelliellid bivalves, by adopting the habit of harbouring symbiotic bacteria in the gills. On the other hand, Stuardo & Valdovinos (1988) specu- lated that vesicomyids might have developed endosymbiosis as an adaptation to reducing sediments, becoming preadaptated to invade the specialized habitat of the hydrothermal vents. The requirement of such a special en- vironment makes the Vesicomyidae good in- dicators of sulfide-rich sediments and/or vents or seeps. The deep sea of the southern Atlantic is scarcely explored for these habitats, and the discovery of a new vesicomyid from off the coast of Parana (25°40'5''S; 44°59'0''W) contributes to the knowledge of the Vesico- myidae distribution and opens new perspec- tives to carry on important research projects that may lead to the discovery of similar sul- fide-rich or reducing habitats and associated communities in southern latitudes. Calyptogena (Calyptogena) birmani, Domaneschi & Lopes, sp. n. Figs. 1-14 Holotype: Museu de Zoologia, Univer- sidade de Sao Paulo (MZUSP) 26691 (Figs. 1—4, 5, 8). Measurements: length: 12.7 mm; height: 8.3 mm; width: 5.2 mm. Paratypes: Museu de Zoologia, Univer- sidade de Säo Paulo 26692 to 26699 (com- plete shells), 26700 to 26705 (odd valves); Departamento de Zoologia, Instituto de Bio- ciéncias, Universidade de Sao Paulo (DZ- IBUSP), without registration numbers, only odd vaives (80 right, 74 left); Academy of Nat- ural Sciences of Philadelphia (ANSP) (two complete shells and ten odd valves: five right, five left); United States Natural Museum (USNM) (two complete shells and ten odd valves: five right, five left). Type-locality: R/V W. BESNARD station 2, 25°40'5''S; 44°59'0''W, off the Paraná coast, Brazil, at a depth of 400 m; sand-clay bottom sediment containing 39.92% calcareous and 1.76% organic matter; water temperature and salinity 2 m above bottom surface respec- tively 15.15°C and 35.55%. Description: Shell to 21.6 mm in length and 15.3 mm in height (largest known specimen— Fig. 14), subtrigonal to elongate ovate (Figs. 11-13), inequilateral, equivalve, rather solid, moderately inflated, with both valves of equal convexity, not gaping (Fig. 1-4). Umbones anterior (1/3 of shell length behind anterior end), small, pointed, weakly involute, proso- cline; umbonal cavity shallow. Anterior margin rather short, convex and uniformly rounded; ventral margin smooth, moderately to Бгоа у convex and rising gently posteriorly; posterior margin at the lower half of the shell height, short and narrowly rounded, forming pointed angular outline; anterodorsal margin short, slightly convex and gently descending, with a weak concavity near the umbones; postero- dorsal margin long, convex to nearly straight, moderately to rather steeply descending. Concentric sculpture consisting of growth lines and weak lirations, best preserved on the anterior and posterior slopes; radial sculp- ture lacking. Radial posterior ridges proceed- ing from the umbones form the posterior dor- sal margin and border a lanceolate, long and deep escutcheon, steeper walled near the umbones. Ligament opisthodetic, light brown, elongate (2/3 of escutcheon length), deeply inset and subtended by thickened, elongate and somewhat protuberant nymphal callosi- ties (ligament lost in most specimens exam- ined or with the periostracal portion present, sometimes associated with residues of the calcareous portion). No lunule; lunular area circumscribed by weakly elevated lines. Left valve with moderately thickened, elongated, shelf-like posterodorsal cardinal tooth and subumbonal cardinal tooth consisting of two portions, the anterior longer, shelf-like and the posterior massive, protuberant; excavated U- shaped socket between them (Figs. 5-7). Right valve with dorsal arched cardinal tooth consisting of a narrow, shelf-like anterior ex- tension which advances forward a short dis- tance from the umbo and a broad, thickened posterior portion; ventral cardinal tooth some- what pointed, elongated, arcuate and extend- ing anteriorly; posterior cardinal tooth lacking (Figs. 8-10, 14). True internal radial rib lack- ing, but rib-like thickening radiating posteri- orly, often present inside umbonal cavity. An- terior adductor muscle scar dorsoventrally elongate, ovate, strongly impressed espe- cially on the posterior margin; posterior ad- ductor muscle scar irregularly rounded, but more weakly impressed. Anterior pedal re- tractor scar deeply impressed, slightly sepa- CALYPTOGENA BIRMANI, N. SP., FROM BRAZIL 365 FIG. 1-4. The holotype of Calyptogena birmani, MZUSP 26691 (length = 12.7 mm): 1, internal view of the left valve showing muscle scars; 2, external view of the right valve; 3, dorsal view of complete specimen showing ligamental area, escutcheon; 4, anterodorsal view of complete specimen to show faintly circum- scribed lunular area. rated from the dorsal end of adductor scar; posterior pedal retractor scar fused with the adductor. Pallial line smooth and convex; pal- lial sinus extremely shallow, broad and rounded (Figs. 11-13). Shell chalky, dirty white, shining; interior white with a central russet stain. Inner margin of the valves in- cised by parallel oblique lines. Measurements (mm) (material deposited in the MZUSP): Specimens with both valves length height width 20.7 12.8 8.7 Paratype (MZUSP 26692) 19:3 13.9 9.9 Paratype (MZUSP 26693) 157 10.6 TE Paratype (MZUSP 26694) 15.4 9.7 6.2 Paratype (MZUSP 26695) 14.8 11.4 ПА Paratype (MZUSP 26696) 14.1 8.6 5.6 Paratype (MZUSP 26697) 12.8 8.3 5.2 ‚Paratype (MZUSP 26698) 127, 8.3 5:2 Holotype (MZUSP 26691) 112 TL 4.7 Paratype (MZUSP 26699) Single valves hemidiameter 21.6 15.3 5.0 (right valve) Paratype (MZUSP 26700) 16.1 10.7 3.4 (left valve) Paratype (MZUSP 26701) 14.2 9.0 2.9 (right valve) Paratype (MZUSP 26702) 12.2 8.1 2.8 (left valve) Paratype (MZUSP 26703) 10.7 7.3 2.3 (right valve) Paratype (MZUSP 26704) 7.8 5.5 1.8 (left valve) Paratype (MZUSP 26705) Remarks: This species is placed in the ge- nus Calyptogena Dall, 1891 (type-species, by monotypy, Calyptogena pacifica Dall, 1891: 190), based on the original description of the genus, the figures given by Boss (1968: 740— 741, figs. 16-17, 19-20) and Keen (1969: N663, fig. E138-11a,b), and the redescription given by Boss & Turner (1980: 162-164). The presence of an escutcheon and the close re- semblance of its hinge plate elements to that of C. pacifica allow the inclusion of this spe- cies in the subgenus Calyptogena 5.5. as es- tablished by Keen (1969), followed and mod- ified by Boss & Turner (1980: fig. 10). Callocardia [ = Vesicomya] albida Dall, 1889: 268, from ALBATROSS station 2762, Rio de Janeiro coast, Brazil, at a depth of 108 m, was the first member of the Vesicomyidae 366 DOMANESCHI & LOPES FIG. 5-7. The dentition of the left valve of Calyptogena birmani: 5, holotype (length = 12.7 mm, area shown = 7.6 mm); 6-7, paratypes (DZ-IBUSP, single valves without registration number) (6, length = 12.5 mm, area shown = 7.5 mm; 7, length = 11.7 mm, area shown = 7.1 mm). Note differences in dental elements. reported from the southwest Atlantic. It is eas- Пу distinguished from Calpytogena birmani by its rounded, inflated shell (Dall’s measure- ments from a single left valve, the only spec- imen known to date: “altitude of shell 8; lon- gitude 9; diameter 7 mm’). Fourteen living species are currently refer- able to Calyptogena, three of which are from the Atlantic (Boss & Turner, 1980; Okutani & Metivier, 1986; Metivier, Okutani & Ohta, 1986; Stuardo & Valdovinos, 1988). The At- lantic species most closely related to C. bir- mani is C. (C.) valdiviae (Thiele & Jaeckel, 1931: 229, pl. 9 (4), fig. 101), from VALDIVIA station 33 (24°35.3'N; 17°4.7'W), about 225 km off Morro Garnet, Rio de Oro, West Africa, at a depth of 2,500 m, and station 103 (35°10.5'S; 23°2’E), about 116 km south of Knysna, Republic of South Africa, at a depth of 500 m. Calyptogena birmani is distin- guished from C. valdiviae by being much smaller, less inflated, having a pointed, angu- lar posterior margin, giving a veneroid outline to most specimens. The anterodorsal margin in С. birmani is convex; that т С. valdiviae is slightly concave, as can be seen in Boss’ (1970) figures 3 and 4, selected by him as lectotype for C. valdiviae, though he de- scribed it as convex. In addition, the posterior ramus ofthe subumbonal cardinal tooth of the left valve is stronger and more elevated than that of C. valdiviae. Calyptogena (C.) ponderosa Boss, 1968: 737-742, figs. 9, 11-15, 18, type-locality M/V Oregon | station 1426 (29°7'N; 87°54’W), about 124 km south of Mobile Bay, Gulf of Mexico, at a depth of 1,097 m, is similar to C. birmani in outline, configuration of the pallial sinus, and internal russet stain, but greatly differs in its much larger size, heavier and thicker shell, more anteriorly placed umbos, rounded adductor muscle scars and distinctly cardinal dentition of both valves. Calyptogena (Ectenagena) modioliforma (Boss, 1968: 742-746, figs. 10, 21-24, 26— 27), type-locality R/V Pillsbury station 394 (9°28.6'N; 76°26.3'W), Golf del Darien, 106 km NNE of Punta Caribana, Colombia, at the CALYPTOGENA BIRMANI, N. SP., FROM BRAZIL 367 FIG. 8-10. The dentition of the right valve of Calyptogena birmani: 8, holotype (length = 12.7 mm, area shown = 7.6 mm); 9-10, paratypes (DZ-IBUSP, single valves without registration number) (9, length = 13.2 mm, area shown = 7.8 mm; 10, length = 11.3 mm, area shown = 7.9 mm). Note differences in dental elements. Figures 9-10 are not from the same specimens shown in Figures 6-7. depth of 421-641 m, is the third Calyptogena previously known from Atlantic waters. The frangible, nearly modioliform shell and larger size of this species readily separate it from C. birmani. More importantly, the presence of a large ligament, lack of an escutcheon and of an anterodorsal cardinal element, traits used by Boss & Turner (1980) to define its subge- neric position in Ectenagena Woodring, 1938: 51 (type-species, by original designation, Ca- lyptogena elongata Dall, 1916: 408), are strik- ing features separating С. modioliforma from С. birmani. The Pacific Calyptogena species most closely related to C. birmani are C. pacifica and C. (Archivesica) kilmeri Bernard, 1974: 17-18, text-figs. 1B, 2B, 3B, 4B and 4E, type- locality FRB station’ 67-50 (53°1'N; 132°56'W) off west coast of Moresby Island, Queen Charlotte Islands, British Columbia, Canada, in 1,170 m. Calyptogena birmani differs from C. paci- fica and C. kilmeri in its smaller size (less than a half of the shell length attained by C. paci- fica and C. kilmeri), longer ligament (2/3 of the escutcheon length in C. birmani, approxi- mately 1/2 in C. pacifica and about 1/3 in C. kilmeri), more convex ventral margin and more angular posterior margin. Calyptogena birmani also differs from C. pacifica by the presence of a distinct pallial sinus and by the hinge traits of its right valve: it has a shorter anterior extension of the dorsal cardinal tooth and absence of any trace of posterior cardinal tooth. The presence of a distinct pallial sinus and absence of any trace of posterior cardinal tooth are traits shared by C. birmani and C. kilmeri. As noted in Boss (1968) and Boss & Turner (1980), there is in Calyptogena a great in- traspecific variation in outline and all dental elements. Figures 5-14 of Calyptogena bir- mani confirm those authors’ observations. Considering the size attained (200 mm or more in length) by specimens of the species of Calyptogena, the examined shells of C. bir- 368 DOMANESCHI & LOPES 5mm FIG. 11-13. Camera lucida drawing of left valves showing shell outlines, hinge and muscle scars of Calyp- togena birmani. 11, a conspicuous subtrigonal, veneroid-type; 12, an intermediate form between 11 and 13; 13. a characteristic oval-elongate type. Note variations in the hinge height, subumbonal cardinal tooth and convexity of the posterior dorsal margin. 11, paratype MZUSP 26696; 12 and 13, paratypes DZ-IBUSP, without registration number. CALYPTOGENA BIRMANI, N. SP., FROM BRAZIL 369 BT? is 5mm Se И ES or Baa 14 FIG. 14. Camera lucida drawing of the largest specimen of Calyptogena birmani (paratype MZUSP 26700). Internal view of the single right valve showing details of the hinge plate and well-impressed anterior muscle scars (adductor and pedal retractor). Valve damaged at the anterior slope; pallial and posterior adductor muscle scars partially vanished by erosion. mani, ranging from 7.8 to 21.6 mm in length, may represent a collection of young of a much larger species. Further collecting in the area where these specimens come from may pro- duce additional material to confirm this premise. Etymology: This species is named for Adol- pho Birman, a physician interested in mollus- can studies and collections, who generously donated the specimens analysed in this pa- per. Observations: The holotype is the best pre- served specimen among all complete ones. Nevertheless, the right valve has the shelf- like anterior extension of the dorsal cardinal tooth slightly broken and the left valve was unfortunately broken during handling for pho- tos, but it was reconstructed later. ACKNOWLEDGMENTS The authors are especially grateful to Prof. Dr. Walter Narchi for the critical review of the manuscript, to the biologist Fabio Moretzsohn de Castro Jr. for assisting with the photos and Dr. Kaoru Hiroki for the English review. LITERATURE CITED BERNARD, Е. R., 1974, The genus Calyptogena in British Columbia with a description of a new spe- cies. Venus, Japanese Journal of Malacology, 33(1): 11-22. BIRMAN, A. & S.G.B.C. LOPES, 1985, Primeira ocorréncia de Vesicomyidae Dall & Simpson, 1901 (Mollusca-Bivalvia), no litoral brasileiro. In: Encontro Brasileiro de Malacologia, 9., Sao Paulo, 1985. Resumos. pp. 45. BOSS, K. J., 1967, A new species of Vesicomya from the Caribbean Sea (Mollusca: Bivalvia: Vesicomyidae). Breviora, 266: 1—6. BOSS, K. J., 1968, New species of Vesicomyidae from the Gulf of Darien, Caribbean Sea (Bivalvia; Mollusca). Bulletin of Marine Science, 18(3): 731-748. BOSS, К. J., 1969, Systematics of the Vesicomy- idae (Mollusca; Bivalvia). Malacologia, 9(1): 254-258. BOSS, K. J., 1970, Redescription of the Valdivia Vesicomya of Thiele and Jaeckel. Mitteilungen 370 DOMANESCHI & LOPES aus dem Zoologischen Museum in Berlin, 46: 67-84. BOSS, К. J. & В. D. TURNER, 1980, The giant white clam from the Galapagos Rift, Calyptogena magnifica species novum. Malacologia, 20(1): 161-194. CAVANAUGH, C. M., 1983, Symbiotic chemoau- totrophic bacteria in marine invertebrates from sulphide-rich habitats. Nature, 302: 58-61. DALL, W. H., 1886, Reports on the results of dredg- ing, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78) and in the Car- ibbean Sea (1879-80), by the U.S. Coast Survey steamer “Blake”, Lieut.-Commander С. D. Sigs- bee, U.S.N. and Commander J. R. Bartlett, U.S.N., Commanding. XXIX. Report on the Mol- lusca. Part 1, Brachiopoda and Pelecypoda. Bul- letin of the Museum of Comparative Zoology, 12(6): 171-318, pl. 1-9. DALL, W. Н., 1889, Preliminary report on the col- lection of Mollusca and Brachiopoda obtained in 1887-88. Proceedings of the United States Na- tional Museum, 12(773): 219-362, pl. 5-14. DALL, W. H., 1891, On some new or interesting West American shells obtained from the dredg- ings of the U.S. Fish Commission Steamer “Al- batross” in 1888, and from other sources. Pro- ceedings of the United States National Museum, 14(849): 173-191, pl. 5-7. KEEN, A. M., 1969, Family Vesicomyidae Dall, 1908. In MOORE, R.C., ed., Treatise on Inverte- brate Paleontology, Part N, vol. 2, Mollusca 6, Bivalvia: 663-664. LANGE DE MORRETES, F., 1949, Ensaio de cata- logo de moluscos do Brasil. Arquivos do Museu Paranaense, 7(1): 5-216. LANGE DE MORRETES, F., 1954, Adenda e cor- rigenda ao ensaio de catálogo dos moluscos do Brasil. Arquivos do Museu Paranaense, 10(2): 37-76. METIVIER, B., T. OKUTANI & S. OHTA, 1986, Ca- lyptogena (Ectenagena) phaseoliformis п. sp., ап unusual vesycomyid bivalve collected by the sub- mersible Nautile from abyssal depths of the Ja- pan and Kurile trenches. Venus, Japanese Jour- nal of Malacology, 45(3): 161-168. OKUTANI, T. & B. METIVIER, 1986, Descriptions of three new species of vesicomyid bivalves col- lected by the submersible Nautile from abyssal depths off Honshu, Japan. Venus, Japanese Journal of Malacology, 45(3): 147-160. RIOS, Е. C., 1970, Coastal Brazilian seashells. Rio Grande, Fundacäo Cidade do Rio Grande, Mu- seu Oceanografico de Rio Grande. 255 pp., 4 maps, pl. 1-60. RIOS, E. C., 1975, Brazilian marine mollusks ico- nography. Rio Grande, Fundacáo Universidade do Rio Grande, Centro de Ciéncias do Mar, Mu- seu Oceanografico. 331 pp., pl. 1-91. RIOS, E. C., 1985, Seashells of Brazil. Rio Grande, Fundaçäo Cidade do Rio Grande, Fundaçäo Uni- versidade do Rio Grande, Museu Oceanografico. 328 pp., pl. 1-102. STUARDO, J. & C. VALDOVINOS, 1988, A new bathyal Calyptogena from off the coast of central Chile (Bivalvia: Vesicomyidae). Venus, Japanese Journal of Malacology, 47(4): 241-250. TURNER, В. D., 1985, Notes on mollusks of deep- sea vents and reducing sediments. American Malacological Bulletin, Special Edition no. 1: 23— 34. TURNER, R. D. & R. A. LUTZ, 1984, Growth and distribution of mollusks at deep-sea vents and seeps. Oceanus, 27(3): 54-62. Revised Ms. accepted 1 November 1989 MALACOLOGIA, 1990, 31(2): 371-380 PENIERSTO THE EDMOR HASZPRUNAR'S “CLADO-EVOLUTIONARY” CLASSIFICATION OF THE GASTROPODA—A CRITIQUE Rudiger Bieler Delaware Museum of Natural History, P.O. Box 3937, Wilmington, Delaware 19807, U.S.A. ABSTRACT A recent classification of the Gastropoda (Haszprunar, 1988b), based on a “clado-evolu- tionary” methodology (Haszprunar, 1986), is analyzed and criticized. Although his publication (1988b) provides a wealth of new anatomical information and a valuable summary of recent research efforts in gastropod systematics, the methodology employed by Haszprunar, combin- ing elements of cladistic data analysis and intuitive evolutionary taxonomy, is considered to be inferior to standard cladistic approaches. The presentation of the data is incomplete and inconsistent. The analysis is not repeatable, Haszprunar's hypothesis of phylogenetic relationships therefore not testable. So-called “cladis- tic” or “sequential” classifications as provided for comparative purposes are improperly or inconsistently derived. Rather than preserving traditional nomenclature as claimed, his “clado- evolutionary” approach leads to the unnecessary naming of monophyletic and paraphyletic groupings. Key words: Gastropoda, systematics, classification, phylogeny, methodology, cladistics, cri- tique. INTRODUCTION Whatever the scientific question, it is an in- tegral part of any study to present the data unambiguously, to employ reproducible meth- ods, and to offer testable hypotheses. The current method of choice among many sys- tematists involved in phylogenetic studies is based on Hennig (1950, 1966), which is a cla- distic analysis that defines monophyletic groups based on internested sets of synapo- morphies (shared derived characters). Pub- lished cladistic studies should provide a char- acter analysis, a listing of taxa and their character states, the means leading to the de- cision of which character state is thought to be primitive or derived (polarity; often by out- group comparison), and at least one graphic representation illustrating the most parsimo- nious or preferred reconstruction of phylog- eny based on the given data set (i.e. a cla- dogram). Often the next step in such a study is the transformation of the information con- tained in the cladogram into a classification. 371 The above procedures force workers to clearly present the data on which the cla- dogram was based. The graphic representa- tion in combination with the data matrix makes it easy to determine how well sup- ported any particular “branch” is; moreover, it also allows one to retrace the transformation into a classification. Other workers are thus able to use, update or falsify the hypotheses presented. In a series of papers, Haszprunar (1985a, b, c, 1988a, b) and Salvini-Plawen 8 Haszprunar (1987) have presented hypotheses of gastro- pod phylogeny as well as associated classifi- cations. These papers summarized many of the recent findings in the field and presented a wealth of new information and original research data, culminating in an extensive publication by Haszprunar (1988b) providing a valuable summary of the field of gastropod systematics. The reader, however, is faced with several difficulties: the papers were published in rapid sequence with various mod- ifications of the same theme, referring exten- 372 BIELER sively to each other and to works in prepara- tion; they contained a plethora of new names for “higher” taxa; and most importantly, the hypotheses of phylogenetic relationships can- not be tested because data matrices were not presented or were incompletely presented, and the methods, in addition to being incon- sistently applied, were not well documented. Haszprunar employed anon-standard, “clado- evolutionary’ method of classification. This method, introduced by Haszprunar (1986) ina German-language paper, is described as combining ‘the advantages of the phyloge- netic (clear retransformation into the phylo- gram) and of the evolutionary method (use of Linnaean categories to express order and di- vergence of groups)” (Haszprunar, 1986: 89). More controversially, it combines the use of clades (monophyletic groups) and grades (paraphyletic groups) in the same classifica- tion. (The term “grade” has been used vari- ously in phylogenetic analyses and classifica- tions in the past. Haszprunar uses it for paraphyletic taxa (stage groups), the third pos- sibility in Hickman’s (1988: 25) discussion of this term.) It is not the aim of this paper to review the individual data employed in Haszprunar's pa- pers, although | am aware of some errors of fact and interpretation’, but rather to docu- ment methodological and technical problems with his approach. | will mainly concentrate on Haszprunar's (1988b) latest, most extensive treatment. His stated goal of “synthesis be- tween cladistics and evolutionary classifica- tion” is “to arrive at a classification which on the one hand can be unequivocally retrans- formed into the basic phylogram, but on the other hand is maximally stable and compati- ble with traditional systems, is maximally practicable, and can be also used by paleon- tologists” (Haszprunar 1988b: 426). There is no question about Haszprunar's acceptance of Henning's method (cladistics) per se. Haszprunar (1988b: 369) stated ‘filt has become essential in phylogenetics to dis- tinguish between synapomorphic (shared de- rived) and symplesiomorphic (shared primi- tive) homologies.” And although Haszprunar uses a form of cladistic methodology to derive a cladogram and then applies his “clado-evo- lutionary” approach to produce a classifica- tion, the confusion stems from how the cla- distic analysis is done and documented, and how the classification is derived from his anal- ysis. | discuss below (a) Haszprunar's (1988b) presentation of the data set, (b) his cladistic analysis leading to a phylogram (1988b: fig. 5), (c) the so-called cladistic, sequential and “clado-evolutionary” classifications derived from this phylogram (1988b: table 5), and (d) Haszprunar's claim that his approach leads to a preservation of traditional names. (a) Presentation of Data Haszprunar does not share his knowledge of character-state distributions with the reader by presenting a complete data matrix. He fre- quently avoids clear statements about the dis- tribution of a character state in the entire group. Is it not present in the other groups; is it not applicable because the character itself is not present; or are the data not yet avail- able? The reader cannot reach a decision based on the presentation. My initial attempt to test a possible interpretation of the data set and the resulting phylogram using available phylogenetic analysis computer programs PAUP (Swofford, 1985) and HENNIG86 (Far- ris, 1988) was abandoned because | was un- able to unequivocally recreate the data matrix from the information contained in the publica- tion (1988b). Haszprunar gives two text listings describ- ing the characters used: table 2, p. 400 (“Review of the character analysis”), and the caption to figure 5 (p. 425). In these listings, he does not distinguish between raw data and interpretation. The numbering system (e.g. 1988b: 425, nos. 1-49) refers to branching points in the phylogram, not to individual char- acters. The reader is forced to search for the information backing a particular branching point in two places in the paper. The listing in Haszprunar's table 2, covering most but not all of the branching points, merely gives the character and its assumed plesiomorphic and apomorphic states, as well as the “number of changes,” the latter frequently given as “many,” without further reference to the type of change. In other cases, the reader is re- ferred to the phylogram (1988b: fig. 5), and the numbers in parentheses are said to cor- respond to that phylogram, e.g. “number of changes . . . several (9p, 31pp, 37),” thus apparently implying multiple occurrences of a change from the plesiomorphic to the apo- morphic state for the same character. The ab- breviation “р” is explained as meaning ‘in part,” while the frequently used abbreviation “pp” is left unexplained in the publication. Ac- cording to Haszprunar (т litt), a single “р” “CLADO-EVOLUTIONARY” CLASSIFICATION 373 refers to a single change within a clade, while “pp” denotes that this change occurs sev- eral times convergently (“mehrfach parallel, konvergent’) within a clade. The second source of information, the caption explaining the phylogram (1988b: fig. 5) matches Hasz- prunar’s table 2 in some cases (e.g. branch 14, presence of ctenidial rods); in other cases, it is apparently meant to supply addi- tional information. It appears to be a some- what expanded version of an earlier listing (Haszprunar, 1988a: fig. 1) that has not been reworked to accommodate the data of table 2 (1988b). For instance step 35 (leading to Campaniloidea and Heterobranchia in the phylogram) is backed by a single change in table 2, from pedal cords to pedal ganglia (with convergences in branches 8, 9 and 30). The description of the phylogram, however, tells us that hypothetical evolutionary step 35 means “chalazae; genital apparatus with spe- cial spermatheca; change of fine-structure of paraspermatozoa.” In the caption of figure 5, no direction of change or the possibility of multiple occurrence is indicated, and the reader can only guess whether the characters described and statements given in the caption of figure 5 are meant to be descriptions of apomorphic character states (e.g. statement to branch 10, “primarily coiled forms (?).” Some confusion can be resolved and some additional data are found in the extensive text. But in some cases the text does not match either the phylogram or the character table and thus adds to the confusion: for example, Hasz- prunar (1988b: 389) states that chalazae are found in “Campanile . . ., in the Valvatidae, in the Architectonicidae and Pyramidellidae, and are generally known in primitive euthy- neurans,” but his “review of the character analysis” (p. 400, table 2) places the character state “connected by chalazae” in branch 39 of the phylogram, thus excluding Campanilidae and Valvatidae. Some of this might be due to sloppiness (as is, for instance, the reversal of branch labels 41 and 42 in the phylogram, figure 5), but many decisions of groupings seem to be based on the author's intuition or knowledge not shared with the reader. (b) Phylogenetic Analysis Haszprunar employs cladistic methodology for the character analysis and the construc- tion of a “phylogram.” As no other information was given, it is assumed that the analysis was done with paper and pencil; i.e. the phylo- gram was derived manually. Today most phy- logenetic analyses of large data sets are han- died with the aid of computer programs, allowing a thorough testing of potential branching patterns present in the data set (e.g. analyses by Davis et al., 1984; Houbrick, 1988; Lindberg, 1988; Bieler, 1988), although excellent analyses of small data sets have been produced manually (e.g. Waller, 1978; Davis & Greer, 1980; Meier-Brook, 1983). Haszprunar, however, did not employ a cla- distic method in standard fashion, but used a “new” approach. Comments on methodology are scattered throughout Haszprunar's paper (1988b: р. 370; table 4, p. 405; p. 426). These comments reveal that the cladistic method is partly mis- represented. Haszprunar (p. 370) states: “Again it is often argued that phylogenetics must be solely based on apomorphies, and again this is simply not true.” He continues by stressing the importance of both plesiomor- phies and apomorphies. The essence of phy- logenetic systematics is the distinction be- tween the two; phylogenetics is not based solely on apomorphies, but phylogenies are. Retained ancestral characters are uninforma- tive about phylogenetic relationships. Hasz- prunar does not use the term “monophyly” in the conventional cladistic sense (Hennig, 1966; Farris, 1974; Wiley, 1981; Ax, 1984), but modifies it from Ashlock’s (1971, 1973, 1979) concept [‘Monophyletic taxon: Taxon which represents a continuous lineage (re- spectively a continuum of generations). Holo- phyletic taxon (= monophyletic sensu Hen- nig): A monophyletic (sensu lato) taxon which includes all descendants of the last common ancestor” (Haszprunar, 1988b: 405, table 4)]. Haszprunar’s conception of “parsimony” also diverges from current usage. He (1988b: 426) claims that his phylogram is the “most parsi- monious.” While in “conventional” cladistic analyses the shortest possible cladogram (and thus the one involving the fewest num- ber of “ad hoc hypotheses” of homoplasy) is viewed as the most parsimonious, Haszpru- nar provides the reader with a vague state- ment: “The concept of parsimony has been much debated, but the term ‘most parsimoni- ous’ is used here in the sense of ‘most prob- able’.” It remains unclear whether his phylo- gram is a result of an attempt to find the shortest possible, based on the data available to Haszprunar, or just an ad hoc one. And, as outlined above, the data are not presented in 374 BIELER a fashion that would allow a test of parsimony by other workers. In his character analysis, all characters are treated as binary ones (1988b: table 2), the concept of multistate characters or any form of complex transformation series is not addressed by the author (although several of the binary characters could be recoded as multistate, for example stereoglossate/flexo- glossate and rhipidoglossate/taenioglossate as docoglossate/rhipidoglossate/taenioglos- sate). The possibility of reversals, the hypo- thetical return to the “primitive” condition, easily construed by loss in case of presence/ absence character states, is not discussed by Haszprunar. Haszprunar's concept of almost linear “pro- gressive” evolution in the gastropods with largely unbranched (or yet-to-be-resolved) “offshoots” from a rhizome-like evolutionary path leading to the Pulmonata seems discom- fortingly teleological. According to Haszpru- паг (1988b: 367) the Allogastropoda, “а grade, .. . represent a step by step evolution towards the euthyneuran level of organiza- tion,” while the “Pulmonata . . . [are] the crown group of Gastropoda.” Almost casual remarks about groups shooting off the path distract from the hypotheses of phylogenetic relationship implied: by viewing the Pyra- midelloidea as the last offshoot before “the euthyneuran level of organization,” Haszpru- nar states that this superfamily is the sister group of the Euthyneura (comprising Opistho- branchia and Pulmonata), a significant state- ment that deserved not to be buried. (c) Classifications Haszprunars nomenclature of classifi- cation methods regains special mention. To | understand his discussions of “clado-evolu- tionary” versus “sequential” and “cladistic” classifications (1986, 1988b) the reader must be aware of Haszprunar’s unique conception of these methods. Because Haszprunar uses modified cladistic terminology, it could easily be overlooked that he is not using conven- tional cladistic methodology. For comparison with his two “clado-evolutionary” classifica- tions, Haszprunar presents (1) a “cladistic” classification and (2) a “sequential” classifi- cation. (1) Haszprunar (1988b: 428, 430, tab. 5) gives a “Cladistic [classification], according to the rules of Hennig (1966)” in the format of an indented listing. Apparently under the impres- sion that a cladistic approach demands nam- ing of all branches or clades (see also Hasz- prunar, 1986: 90), he names all but one branching point. The naming is done by using quotation marks, without citing authorship for named taxa (most of them are apparently new)”. The method of indenting the taxa ac- cording to their sister group relations is either incorrectly applied, or secondarily brought out of order due to a printer's error (see Doco- glossa to “Helicoida” in table 5(d)). In contrast to the other classifications offered, Haszpru- nar uses an unranked order in the “cladistic classification.” In an attempt to distinguish his “clado-evo- lutionary” method from other, more-or-less differing approaches, Haszprunar narrowed the concept of “cladistic classification” by de- fining it as something that Wiley (1979: 317; 1981: 203) called “subordination by pure in- dentation,” a method rarely used in today's phylogenetic classifications of mollusks. (Haszprunar derives most of his examples (1986) from work on Platyhelminthes by Ax and Ehlers; e.g. in Ax, 1984.) This approach can be very useful for ascheme containing a small number of ranked and unranked taxa and is ideal for preliminary groupings since it avoids preliminary names (see also Gauthier et al. (1988)). (2) The second non-‘clado-evolutionary” classification presented by Haszprunar (1988b: 428, 430, “(с)”) is labeled as “se- quential, according to the rules of Wiley (1979, 1981).” The “rules of Wiley’? are not specific to sequential classifications but are intrinsic to any phylogenetic classification (Wiley, 1981: 199). Sequencing was ad- dressed by Wiley in “convention 3” (1979: 319, 321; 1981: 209), based on the phyletic sequencing convention of Nelson (1972, 1974). Neither Wiley (1981) nor Haszprunar considered these as part of the “rules”; Hasz- prunar, without making a clear statement, ap- plies most of Wiley’s (1981) conventions for annotated Linnaean classifications, while partly ignoring others (see below). Haszprunar’s example of “sequential clas- sification” (1988b: table 5 (c)) is difficult to interpret. This is partly due to confusing tech- nicalities such as the introduction of names not present in the phylogram (“Flexoglos- sata,” “Taenioglossa”), the absence of groups that were in the phylogram (e.g. Omal- ogyridae), and the inconsistent use (and in- terpretation in Haszprunar’s classifications) of symbols coding for tentative placement ee “CLADO-EVOLUTIONARY” CLASSIFICATION 375 (dotted line, dashed line, question mark, box). Haszprunar applies the same sequencing convention’ in classification “(с)” and in his “clado-evolutionary” classifications. The puz- zling part is that he uses the convention in very different ways in the two approaches: in “(c),” meant to be an example for a “se- quential classification,” he changes without explanation to subordination after the first three taxa. Because this classification “(с)” differs greatly from the others, | attempted to retrace the transformation of Haszprunar's phylo- gram (1988b: fig. 5) into a strict “sequential” classification. For this, | used the following ap- proach. To avoid naming and categorizing ev- ery branching point, Nelson's phyletic se- quencing convention was utilized. Names in brackets are other names used by Haszpru- nar (1988b) as redundant categories for mo- notypic taxa, with some of the more confusing misspellings (or unmarked new names?) in single quotes. As in Haszprunar's classifications, Wiley's (1979) sedis mutabilis label is used, indicating taxa of interchangeable position at that level. This classification allows for unequivocal re- transformation of the clades. The Cerithioidea (Cerithiimorpha) nebulously addressed as the “basic stock” and placed within a branch of his phylogram (Haszprunar, 1988b: 415 and fig. 5) could not be interpreted. The resulting classification derived from Haszprunar's phy- logram is here given in Table 1. The classification (Table 1), derived with established cladistic procedures should be largely congruent with Haszprunar's classifi- cation “(с)”, but it is not. Instead the classifi- cation in Table 1 differs little from Haszpru- nars ‘clado-evolutionary” classifications (compare Table 1 with Haszprunar’s 1988b: 428, table 5(a), here reproduced in Table 2). If, for instance, all taxa (except Euthyneura) of the first level of indentation in Table 1 were categorized as suborders, only two differ- ences are found: (1) Haszprunar interprets Melanodrymia and Neomphaloidea as be- longing to Neritimorpha (thus diverging from his own phylogram, claimed to be the “most probable reconstruction of gastropod phylog- епу”; 1988b: 426), and (2) he places the groups Omalogyridae to Pyramidellidae in a paraphyletic taxon *Allogastropoda”. What then is Haszprunar's new approach? His “clado-evolutionary classification” claims to be a “new synthesizing methodology,” combining “the advantages of the phyloge- TABLE 1. Cladistic classification derived from Haszprunar's phylogram (1988b: 424, figure 5), employing Nelson's phyletic sequencing method. Haszprunars dashed and stippled lines were interpreted as tentative placements and are here indicated by question marks “(?)”. His question marks were interpreted as unresolved polychotomies, the taxa involved marked with Wiley's sedis mutabilis “(s.m.)” label. The position of Cerithiimorpha could not be interpreted, and the group is here omitted. The grade comprising the paraphyletic group Allogastropoda is marked separately. Docoglossa Patelloidea Nacelloidea “Hot-Vent-C” (?) Cocculiniformia Cocculinoidea Lepetelloidea Neritimorpha (4 superfamilies) Melanodrymia (?) ["Hot-Vent-A”] Neomphalus (?) [Neomphaloidea, ‘Neomphalida’] Vetigastropoda (?) Lepetodriloidea (s.m.) Fissurelloidea (s.m.) Scissurelloidea (s.m.) Haliotoidea (s.m.) п.п. (s.m.) Pleurotomarioidea Trochoidea Seguenzioidea [Seguenziina, ‘Seguenziida’] Architaenioglossa (?) Cyclophoroidea (s.m.) Ampullarioidea (s.m.) [Viviparina] Caenogastropoda [excluding *Cerithiimorpha*, *Cerithimorpha””'] Ctenoglossa (s.m.) “Neotaenioglossa” (part.) (s.m.) n.n. (s.m.) “Neotaenioglossa” (part.) Stenoglossa Campaniloidea [Campanilimorpha] Valvatoidea [Ectobranchia] n.n. Omalogyridae (7?) Architectonicoidea Rissoelloidea Glacidorboidea Pyramidelloidea Euthyneura [= Pentaganglionata] “Allogastropoda” netic ... and evolutionary method” (Haszpru- nar, 1986: 89). Haszprunar, who sees his technique of deriving a classification as a se- quel to “Wiley's” sequential method (Hasz- prunar, 1986: 91), employs well-known ap- proaches, such as the aforementioned phyletic sequencing convention oí Nelson, and Wiley's sedis mutabilis label. He then ex- 376 BIELER TABLE 2. Reproduced from Haszprunar (1988b: 428, table 5(a)), entitled "Classification of the Recent streptoneuran Gastropoda. (a) Clado- evolutionary, primarily based on the nervous system (the preferred version).” (Author and date citations left out. Originally listed superfamilies of Cteno- glossa, *Neotaenioglossa* and Stenoglossa omit- ted, because they were not part of the phylogram.) Class GASTROPODA Subclass *Streptoneura* Order *Archaeogastropoda* Suborder DOCOGLOSSA Superfamily Patelloidea Superfamily Nacelloidea ?Suborder “HOT-VENT GROUP-C” Suborder COCCULINIFORMIA Superfamily Cocculinoidea Superfamily Lepetelloidea Suborder NERITIMORPHA Superfamily *Neritoidea* Superfamily Titiscanioidea (s.m.) Superfamily Hydrocenoidea (s.m.) Superfamily Helicinoidea (s.m.) ??Superfamily “Hot-vent group А” (Melanodrymia) ??Superfamily Neomphaloidea Suborder VETIGASTROPODA Superfamily Lepetodriloidea (s.m.) Superfamily Fissurelloidea (s.m.) Superfamily Scissurelloidea (s.m.) Superfamily Haliotoidea (s.m.) Superfamily Pleurotomarioidea Superfamily Trochoidea Suborder SEGUENZIINA Superfamily Seguenzioidea Suborder *ARCHITAENIOGLOSSA” Superfamily Cyclophoroidea (s.m.) Superfamily Ampullarioidea (s.m.) (= Viviparoidea) Order *Apogastropoda* Suborder CAENOGASTROPODA Section *Cerithiimorpha* Superfamily *Cerithioidea* Section Ctenoglossa (s.m.) Section *Neotaenioglossa* (s.m.) Section Stenoglossa Suborder CAMPALINIMORPHA Superfamily Campaniloidea Suborder ECTOBRANCHIA Superfamily Valvatoidea Suborder *~ALLOGASTROPODA* Superfamily Achitectonicoidea ?incl. Omalogyridae (= Prionoglossa) Superfamily Rissoelloidea Superfamily Glacidorboidea Superfamily Pyramidelloidea Subclass Euthyneura (= Pentaganglionata) pands on a topic discussed by earlier authors (e.g. Patterson & Rosen, 1977; Wiley, 1979, 1981): the utilization of especially marked paraphyletic assemblages in classifications. He is thus largely following Wiley’s conven- tions for annotated Linnaean classifications (Wiley, 1981: 205-213), and up to this point Haszprunar has reinvented the wheel, con- sidering that these are standard components of many modern phylogenetic analyses. (For a recent classification derived with this method and additional discussion see, for in- stance, Christoffersen (1987).) Haszprunar uses three “new” approaches: (1) The splitting of paraphyly sensu Ashlock® into paraphyly s./. and orthophyly (a lineage system with only a single emerging line not included®), and the acceptance of only the lat- ter in classifications. (2) The ranking of para- phyletic groupings (in contrast to Wiley’s “convention 6”). (3) The replacement of a standardized or at least documented conven- tion (e.g. Farris, 1976) to achieve categoriza- tion with the vague method inherent to “evo- lutionary taxonomy”: instead of an objective and reproducible analysis of the data at hand he nebulously selects his “most suitable vari- ation . .. by taking the anagenetic component into consideration,” Supplemented by “practi- cability and compatibility with traditional sys- tems” (Haszprunar, 1986: 89). This allows him to select one or several “preferred ver- sions” of classifications with only limited con- nections to the data base and phylogram generated earlier, and it explains why Hasz- prunar's “clado-evolutionary” classifications (1988b: 428-429, tab. 5 (a), (b)) cannot be reproduced from his phylogram. The use of paraphyletic taxa thus allows Haszprunar to reach an agreeable (precon- ceived?) classification. As de Queiroz puts it: “Using phylogenetic definitions reveals the arbitrariness of paraphyletic taxa, for they must be defined as a common ancestor and only some of its descendants, and one group of descendants can be removed as well as any other” (1988: 254). With de Queiroz (1988), | view paraphyletic grades as hold- overs from “preevolutionary” taxonomies based on the Scala Naturae, or great chain of being. “The recognition of paraphyletic grades as taxa depends on emphasizing the derived traits of certain descendants (for ex- ample, birds) over those of others (for exam- ple, turtles) and, therefore, obscures the mo- saic nature of evolution. The implication of paraphyletic grade taxa is that their various subgroups either did not evolve, which is sim- ply incorrect, or that they did not evolve in an “CLADO-EVOLUTIONARY” CLASSIFICATION 377 important direction, which is a subjective judgment rather than a fact of nature” (de Queiroz, 1988: 252). (d) Preservation of Traditional Names One of the stated goals of Haszprunar's method is to arrive at a Classification that is “maximally stable and compatible with tra- ditional systems’ [emphasis mine] (1986: 89). The formal recognition of non-monophyl- etic groupings is thus justified by the argu- ment that considers “traditional components” (1986: 89) a primary property of a classifica- tion (see e.g. Michener, 1977, for additional example). Stability and convenience in clas- sification are certainly desirable as long as analyses are not hampered and concepts not compromised. The goal of phylogenetic sys- tematics is to estimate phylogeny, not to maintain stability (see also Kluge, 1989). Can a method which seeks to maintain stability of names and hierarchies established by essen- tialists, creationists and pheneticists be “evo- lutionary”? In any case, Haszprunar's claim that one major advantage of the “clado-evolutionary method” of classification is the fact that it does not introduce unnecessary names, 1$ not true. lt always depends on the individual worker whether clades or grades in any given analysis are named. A review of many cladis- tic analyses in the recent malacological liter- ature will show that very few authors find it necessary to name every branching point in a cladogram when transforming it into a classi- fication. Several devices exist to avoid exces- sive naming, such as the application of the sequencing convention (Nelson, 1972, 1974), the suggested abandonment of Hennig's prin- ciple (1966: 155) that sister groups must have the same absolute rank (Farris, 1976), or the use of informal groupings such as “taxon A + taxon B + taxon C.” Haszprunar rigorously adheres to Hennig’s view and, against current convention (e.g. Wiley, 1979: 315; 1981: 205; Ax, 1984: 253), introduces redundant names (even for monotypic taxa) whenever he changes the rank of that taxon in a classifica- tion. There is no excuse for the introduction of new names in a classification considered as being prelimininary or, as in the case of Hasz- prunar's classification “(c)” (1988b: 430), in one considered a less preferred example! Haszprunar (1988a: 14) further claims that his “system is largely compatible with previ- Sus ones by using traditional taxa (any rigor- ous cladistic classification would reject para- phyletic taxa such as the Archaeogastropoda or Streptoneura).” While some might see it useful to preserve names of taxa recognized as para- or polyphyletic (such as Archae- ogastropoda’ and Mesogastropoda) by using them as names for stage groups or grades, it is interesting to note that most of Haszpru- nar's *to be protected* names are not “tradi- tional.” Of the eight higher category names flagged by Haszprunar (1988b: fig. 5) as rep- resenting “orthophyletic” groups (= para- phyletic, and thus not acceptable in a cladistic classification), five are not traditional at all: Allogastropoda Haszprunar, 1985; Apogas- tropoda Salvini-Plawen & Haszprunar, 1987; Cerithiimorpha Golikov & Starabogatov, 1975; and Architaenioglossa and Neotaenio- glossa, both Haller, 1892, and recently re- vived by Haszprunar (1985a) to replace Thie- les Mesogastropoda. If one of Haszprunar’s main goals is the preservation of traditional names and thus no- menclatural stability, why did he replace Het- erogastropodaKosuge, 1966, by Heteroglossa Haszprunar, 1985 (1985a: non Heteroglossa Gray, 1857), and Euthyneura Spengel, 1881, by Pentaganglionata Haszprunar, 1985 (1985c), in the first place? Perhaps it is more than ironic that Haszprunar has not utilized Minichev & Starogobatov (1979) who subdi- vided the gastropods into eight subclasses, introducing a considerable number of new names for higher taxa which in part overlap with Haszprunar's groupings. | agree with Ponder (1988: 3) that “[i]f classification is to achieve a reasonable level of stability then higher groups should not receive new names simply because existing names were pro- posed to encompass wider or narrower groupings than the ones which a current anal- ysis is identifying. ... Likewise the argument that an existing higher group name is not suit- able because it is based on characters that do not apply to all members of the group (e.g. not all Opisthobranchia have posterior gills), or to some groups (or parts of groups) outside it, is also certain to cause instability.” CONCLUSIONS (a) The presentation of the data set in Haszprunar's publication (1988b) is incom- plete and inconsistent. Raw data and inter- pretation are mixed. (b) The analysis is not repeatable; Hasz- 378 BIELER prunar's hypothesis of phylogenetic relation- ships is not testable. (с) Classifications labeled “cladistic” and “sequential,” which were used by Haszprunar (1988b) in comparison with his “clado-evolu- tionary” classifications, are improperly or in- consistently derived. The procedures leading from the phylogram to the various classifica- tions presented are not documented and can not be reconstructed from the published data. (d) Rather than preserving traditional no- menclature, Haszprunar’s approach leads to the unnecessary naming of monophyletic and paraphyletic groupings. The question is whether the frequency of new-and-improved higher level classifications in the recent literature reflects major steps in the accumulation of knowledge of mere pre- mature publications during an exciting time of data gathering in the field of malacology. Haszprunar's “clado-evolutionary method” attempts to legitimize an ad hoc scheme based on incomplete data. | do not criticize Haszprunar for the incompleteness of these data; on the contrary, his excellent anatomical work has closed many gaps in our knowledge and has forced us to re-analyze entrenched hypotheses of phylogenetic relationships. However, in his endeavor to combine the un- combinable in a “clado-evolutionary” pot- pourri, he has blurred the distinction between phylogenetic analysis based on “hard” data and the intuitive and authoritarian taxonomy of days past. ACKNOWLEDGMENTS This contribution originates from extensive and lively discussions (about gastropod clas- sifications in general and Haszprunar's ap- . proach in particular) with a number of col- leagues. | am especially grateful to the following for reading and expertly criticizing an earlier draft of my manuscript: Drs. Jonathan A. Coddington and Richard S. Houbrick (National Museum of Natural His- tory, Smithsonian Institution, Washington, D.C.), Dr. Kenneth J. Boss and Mr. Alan R. Kabat (Museum of Comparative Zoology, Harvard University, Cambridge, Massachu- setts), Drs. George Davis and Gary Rosen- berg (Academy of Natural Sciences of Phila- delphia, Pennsylvania), Dr. David R. Lindberg (Museum of Paleontology, University of Cali- fornia, Berkeley, California), and an anony- mous reviewer. Nonetheless, | assume sole responsibility for the points of view expressed in this paper. LITERATURE CITED ASHLOCK, P. D., 1971, Monophyly and associated terms. Systematic Zoology, 20(1): 63-69. ASHLOCK, P. D., 1973, Monophyly again. System- atic Zoology, 21(4): 430-438. ASHLOCK, P. D., 1979, An evolutionary system- atist's view of classification. Systematic Zoology, 28(4): 441-450. AX, P., 1984, Das Phylogenetische System. Sys- tematisierung der lebenden Natur aufgrund ihrer Phylogenese. Gustav Fischer Verlag, Stuttgart, New York, 349 pp. BIELER, R., 1988, Phylogenetic relationships in the gastropod family Architectonicidae, with notes on the family Mathildidae. Malacological Review, Supplement 4 (Prosobranch Phylogeny): 205— 240. BIELER, R. & Р. М. 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L., 1985, PAUP—Phylogenetic analysis using parsimony, version 2.4 (Docu- mention and IBM PC-compatible program pack- age). Illinois Natural History Survey. WALLER, T. R., 1978, Morphology, morphoclines and a new classification of the Pteriomorpha (Mollusca: Bivalvia). Philosophical Transactions of the Royal Society of London, (B)284: 345— 365. WILEY, Е. O., 1979, An annotated linnaean hierar- chy, with comments on natural taxa and compet- ing systems. Systematic Zoology, 28(3): 308- SO WILEY, Е. O., 1981, Phylogenetics. The theory and practice of phylogenetic systematics. John Wiley & Sons, New York, xv + 439 pp. Revised Ms. accepted 22 January 1990. APPENDIX: NOTES 1. Examples: Bieler & Mikkelsen (1988) did not describe a bipectinate gill in Vitrinellidae (used as a character by Haszprunar, 1988b: 381), but rather a monopectinate one; and Bieler (1988) found more than “only the shape of the osphradium and the radula” to distinguish Architectonicidae and Mathildidae (Haszprunar, 1988b: 420), e.g. the opercular morphology (with peg in Architectonicidae). 2. Haszprunar enclosed a disclaimer con- cerning these names (1988b: 428), stating that “[а] “Taxon” has no nomenclatorical status.” These taxa are not to be confused with “orthophyletic” taxa [see note 6] origi- nally demarcated by quotation marks (Hasz- prunar, 1986): Hasprunar (1988b: 426) now considers it “preferable to mark the orthophyl- etic taxa by stars (*) instead of quotation marks (“).” These in turn should not be con- fused with the annotations proposed by Gau- thier et al. (e.g. 1988: 16), with quotation marks denoting known paraphyletic groups and the asterisk (*) identifying so-called metataxa, i.e. “taxa for which there is no char- acter evidence supporting either monophyly or paraphyly.” 380 BIELER 3. “Rule 1. Таха classified without qualifi- cation are monophyletic groups sensu Hennig (1966). Nonmonophyletic groups may be added if they are clearly qualified as such. Rule 2. The relationships of taxa within the classification must be expressed exactly” (Wiley, 1981: 200). 4. “Convention 3. Taxa forming an asym- metrical part of a phylogenetic tree may be placed at the same categorical rank . . . and sequenced in phylogenetic order of origin... with the first taxon listed being the sister group of all subsequent taxa. . .” (Wiley, 1981: 209). 5. Ashlock (1971: 69): “А paraphyletic group is a monophyletic group that does not contain all of the descendants of the most common ancestor of that group.” 6. “Orthophyletic taxon: A paraphyletic taxon which represents a (usually branched) lineage-system with only a single emerging line not included. This type is marked as “taxon” and can be used in a clado-evolu- tionary system.” (Haszprunar, 1988b: 405). 7. Although | favor Hickman's (1988: 28) suggestion to use the taxon Archaeogas- tropoda, in a restricted sense, for a monophyl- etic group equivalent to (and thus replacing) Vetigastropoda Salvini-Plawen, 1980. The editor-in-chief of Malacologia welcomes let- ters that comment on vital issues of general im- portance to the field of Malacology, or that com- ment on the content of the journal. Publication is dependent on discretion, space available and, in some cases, review. Address letters to: Letter to the Editor, Malacologia, care of the Department of Malacology, Academy of Natural Sciences, 19th and the Parkway, Philadelphia, PA 19103. MALACOLOGIA, 1990, 31(1-2): 381-397 INDEX Taxa in bold are new; page numbers in bold indicate pages on which new taxa are described; pages in italics indicate figured taxa; an asterisk (*) indicates a non- molluscan taxon. Abra ovata 291 abronia, Trinchesia 283 Acamaea 263 Acanthochiton crinitus 214 Acanthodoris pilosa 282 Acavacea 341 Acavidae 341-344, 352 Acavoidea 343, 344, 347, 348, 351, 352 accepta, Fonscochlea 8, 15, 18-24, 26- 27, 29-30, 32-34, 36-39, 56, 73-79, 74, 75, 77, 82-89, 91, 97-99, 101, 102, 125-130 Acella haldemani 284 Achatina achatina 286 fulica 286 achatina, Achatina 286 Achatinacea 341 Achatinella mustelina 286, 288 Achatinellacea 341, 343 Achatinellidae 286, 341-344, 352 Achatinelloidea 342, 343 Achatinida 328, 343, 347 Achatinidae 286, 341-344, 351 Achatinina 328, 342, 346, 350 Achatinoidea 342, 343, 344, 346, 348, 350, 351 Acila insignis 289 Acmaea antillarum 280 digitalis 280 dorsuosa 280 insessa 280, 283 paradigitalis 280 pelta 280 scabra 280 Acmaeidae 212, 280 Acochlidium 245,265 Acroloxidae 249, 250, 252-254 Acteonidae 282 acuta, Hydrobia 284 acuta, Physa 285 acuta, Pleurocera 198 acutispira, Littorina 267, 270, 280 acutocarinata, Goniobasis 198, 199 Adalaria proxima 282 adamsi, Callithaca 291 Adamusium colbecki 289 Aegopinella 264 nitens 286 nitidula 286, 288 . Aeolidia papillosa 283 Aeolidiidae 283 Agriolimacidae 349-352 Agriolimax laevis 225 reticulatus 217 Aillyida 346 Aillyidae 345-348 Aillyoidea 347 alabamensis, Goniobasis 198, 199 alaskana, Vitrina 286 albicilla, Nerita 280 albida, Callocardia 363, 365 albidus, Chlamys 289 albocrusta, Trinchesia 283 albolabris, Neohelix 329, 333 albus, Petasites* 217-227 albus, Planorbis 285 Alepisaurus* 319-321 Allogastropoda, 375, 376 Allogona profunda 287 alpha, Catronia 283 alta, Siliqua 290 alternata, Anguispira 329 alternata, Tellina 291 alticostata, Patelloida 280 amarula, Thiara 242, 244 Amastridae 341-344 Amblema plicata 293 ameghini, Veronicella 286, 288 americana, Thyonicola* 283 Ammonitellidae 345-352 Amnicola limosa 284 amnicum, Pisidium 293 amoena, Trinchesia 283 Ampnibolacea 251, 252 Amphibulimidae 345-348 Amphiura* 292 Amplirhagada napierana 287 Ampullarioidea 375, 376 amurensis, Potamocorbula 292 Amusium balloti 289 amyra, Doto 282 Anadara broughtoni 289 Anadromidae 349-352 anatina, Anodonta 293 Anatontoides subcylindraceus 293 Ancula cristata 282 Anculosa 197 Ancylidae 285 Ancyloplanorbidae 250, 254 Ancylus 266 fluviatilis 285 lacustris 285 Anguispira alternata 329 angulosa, Doninia 291 Aniscorbula venusta 292 Anisus vortex 285 annandalei, Pisidium 293 annulata, Nucula 289 Anodonta anatina 293 californiensis 293 corpulenta 293 382 INDEX gibbosa 293 grandis 205 Imbecilis 293 minima 293 peggyae 293 piscinalis 293 woodiana 293 anodontoides, Lampsilis 293 Anomalocardia squamosa 291 antillarum, Acmaea 280 antillarum, Ornithoteuthis 314, 317, 320- 321, 324 antipodarum, Potamopyrgus 284 antiqua, Neptunea 281 Aperidae 341-344, 349-352 aperta, Philline 284 apiculata, Chaetopleura 261 Aplexa hypnorum 285 Aplysia californica 282 depilans 282 fasciata 282 juliana 282 kurodai 282 punctata 282 Aplysiamorpha 268 Aplysiidae 282 Apogastropoda 334, 376 aquatica, Fonscochlea 8, 15, 20-24, 27- 29, 30-31, 32-34, 34-35, 36, 37-39, 48, 56, 82-89, 94, 95, 97-102, 105, 125-130 arbustorum, Arianta 267, 270, 287 Arca boucardi 289 Archachatina marginata 286 Archaeogastropoda 211-216, 327-352, 376, 377. Archidorididae 283 Archidoris pseudoargus 283 Architaenioglossa 375-377 Architectonicidae 373 Architectonicoidea 375, 376 Archivesica 367 Arcidae 289 Arctica islandica 291 Arcticidae 291, 363 arcticus, Bathypolypus 295 arenaria, Catinella 286 arenaria, Mya 292 arenatus, Conus 281 arenosa, Xeropicta 288, 359 Argopecten gibbus 289 Irradians 269, 289 japonicum 289 Arianta arbustorum 267, 270, 287 Arion 264 ater 217, 225, 226, 286 circumscriptus 286 hortensis 286 intermedius 286 rufus 217 subfuscus 286 Arionacea 345, 347 Arionidae 286, 345-352 Arionoidea 346, 347 Ariophantidae 345-352 Armiger cristata 285 arrosa, Helminthoglypta 287 arthurii, Melanoides 242, 244 aspersa, Helix 217, 225, 287 aspersa, Patella 279 asperulata, Neritina 242, 245 aspirans, Melanoides 244 Assiminea crosseana 243, 244 Assimineidae 237, 240, 243 ater, Arion 217, 225, 226, 286 ater, Viviparus 284 Athoracophora 328 Athoracophorida 346 Athoracophoridae 269, 345-348 Athoracophoroidea 347 atomus, Omalgyra 280 atramentosa, Nerita 280 atropurpura, Pinna 265, 289 attramentaria, Batillaria 281 Aulacopoda 327-329, 345, 347, 351 aulacospira, Erinna 239 auricularia, Dolabella 282 auriculata, Neritina 242, 244 australis, Calyptogena (Ectenagena) 363 Austrochiltonia* 91, 93, 104 Austropelpa vinosa 284 balanoides, Balanus* 229 Balanus balanoides* 229 balloti, Amusium 289 balthica, Macoma 290 Bankia gouldi 292 barbadensis, Fissurella 279 Barleeia 267, 283 unifasciata 280 bartramii, Ommastrephes 315-316, 317, 324 bartschi, Teredo 292 Basommatophora 235, 251, 327-352 Bathymodiolous thermica 292 thermophila 289 ls arcticus 295 Batillaria attramentaria 281 Beddomeia complex 64 beieri, Monacha 353 belauensis, Nautilus 297-312; 299, 300, 302, 306, 307309 bellicosa, Thiara 244 bicolor, Pinna 265 bidens, Brephulopsis 286 bidentata, Mysella 290, 292 Bielzia 264 coerulans 287 bilamellata Onchidoris 282, 284 billakalina, Fonscochlea 8, 20, 21, 27, 38, 39, 45, 46, 48, 49, 48-49, 50, 51, 51, 53-55, 98, 99, 101, 105, 131-134 Biomphalaria 211, 266, 327, 332, 334, 336, 337 glabrata 285, 329, 333, 336 guadeloupensis 329 pfeifferi 285 birmani, Calyptogena (Calyptogena) 363- 370; 364-369, 365-369 INDEX Bithynia 266 leachi 284 tentaculata 284, 285 Bithyniidae 284 Boetgerillidae 349-352 bonnevie, Enteroxenos 281 borellianus, Vaginulus 286, 288 boucardi, Arca 289 Brachiodontes variabilis 289 Brachynephra 328, 344, 348, 352 Bradybaena fruticum 217, 226, 287, 353, 358-360 Bradybaenidae 287, 349-352 Brephulopsis 266 bidens 286 brevior, Fluviopupa 239, 245 brevisiphonata, Callista 291 briareus, Octopus 295 Brotia hainanensis 284 broughtoni, Anadara 289 Buccinidae 281 budapestensis, Milax 287 Buliminidae 341-344 Bulimnoidea 343, 351 bulimoides, Limacina 282 Bulimulacea 328, 345, 347 Bulimulidae 287, 352 Bulimulidea 345-348 Bulimulus 266 dealbatus 287 Bulinus 211, 249, 266 forskalii 285 globosus 285 nasutus 285 Bullia rhodostoma 281 Bullomorpha 268 Byssanodonta cubensis 293 byssifera, Hiatella 292 Cadella lubrica 290 Caenogastropoda 375, 376 calcarea, Macoma 290 caledonica, Hemistomia 245 californica, Aplysia 282 californica, Hancockia 282 californiensis, Anodonta 293 californiensis, Mytilus 289 californiese, Keenocardium 290 Callianassa major 192 Callista brevisiphonata 291 chione 291 callistiformis, Tindria 289, 292 Callithaca adamsi 291 Callocardia albida 363, 365 Calyptogena magnifica 291, 292 (Archivesica) kilmeri 367 (Calyptogena) irmani 363-370; 364-369, 365-369 pacifica 365, 367 ponderosa 366 valdiviae 366 (Ectenagena) australis 363 elongata 367 modioliforma 366, 367 383 Calyptraea chinensis 281 Calyptraeidae 281 Camaenacea 345, 349 Camaenidae 287, 345-352 Camaenoidea 347, 351 Campanile 373 Campanilimorpha 375, 376 Campaniloidea 375, 376 Campeloma 285 rufum 284 canaliculatum, Pleurocera 198 canalis, Neritina 242, 244 cancellata, Thiara 242 cancellatum, Trichotropis 281 capax, Tresus 290 caperata, Helicella 287 capitata, Limapontia 282 Caracolus caracolus 287 caracolus, Caracolus 287 Cardiidae 290 Carditidae 290 Cardium ciliatum 290 corbis 290 edule 290 carinata, Leptoxis (Mudalia) 198 carinata, Leptoxis 217, 284, 285 carinatus, Planorbis 285 cariosus, Clithon 239 cartusiana, Monacha 287, 353-362 Carychium 264, 267, 288 tridentatum 286, 288 Caryodidae 341-344, 352 casertanum, Pisidium 293 catenaria, Goniobasis 198, 200, 201 Catinella 264, 266 arenaria 286 Catronia alpha 283 caucasicum, Deroceras 287 caurinus, Patinopecten 289 Cavatidens omissa 290 Cavolina 264 Cavolinia gibbosa 282 Cavoliniidae 282 Cellana grata 279 radiata 279 tramoserica 279 cellarius, Oxychilus 286 cema, Ceratobornia 192 Cepaea nemoralis 226, 287 vindobonensis 353 Cephalopoda 297-312 Cerastoderma edule 229 glaucum 290 Cerastuidae 349-352 Ceratobornia 190, 192 cema 192 longipes 192 Ceriidae 341-344 cerinoideus, Ventridens 329, 333 Cerion spp. 286 Cerionidae 286, 341-344 Cerithidea decollata 281 384 INDEX Cerithiidae 281 Cerithiimorpha 375-377 Cerithium 263 coeruleum 281 eburneum 281 lutosum 281 muscarum 281 rupestre 281 scabridum 270, 281 Cernuella 266 virgata 287, 288, 359 Chaeotpleura apiculata 261 Charopidae 269, 345-348, 352 Chilinidae 249, 250, 252-254 chinensis, Calyptraea 281 chione, Callista 291 Chlamydephoridae 341-344, 349-352 Chlamydoconcha 264 orcutti 191 Chlamydoconchidae 264 Chlamys albidus 289 islandica 289 opercularis 289 varia 289 Chondrinidae 286, 341-344 Chondrinoidea 344 Chromodorididae 283 Chromodoris nodosus 283 zebra 283 Chthamalus* 230, 233, 234 ciliatum, Cardium 290 cinerea, Urosalpinx 281 Cionellacea 328, 341, 343 Cionellidae 341-344 Cionelloidea 328, 342 circumscriptus, Arion 286 cirrhosa, Eledone 295 clarkeanum, Pisidium 293, 294 Clausilacea 343 Clausiliacea 341, 343 Clausiliidae 286, 341-344 Clausilioidea 342, 343, 344, 346, 348, 350 Clavatoridae 341-344 clavigera, Limacia 283 clavigera, Thais 281 Clinocardium nuttallii 229, 290 Clio 264 pyramidata 282 Clithon 244, 245 cariosus 239 corona 241, 243 corona 243 diadema 243, 244 neglectus 239 nucleolus 243, 245 olivaceus 243, 244 oualaniensis 243, 244 pritchardi 243-245 rarispina 244 spinosus 243 coccinea, Littorina 280 coccineum, Pleurobema 293 Cocculiniformia 375, 376 Cocculinoidea 376 cochlear, Patella 279 Cochlicopa 264 lubrica 286 Cochlicopidae 286 Cochliocopidae 341-344 Cochliocopoidea 328 Cochlodina laminata 286 Coeliaxidae 349-352 coerulans, Bielzia 287 coeruleum, Cerithium 281 coindetti, Illex 318, 321, 324 colbecki, Adamusium 289 Coleoidea 295 columella, Cuvierina 282 complanata, Elliptio 293 compressum, Pisidium 293 concavum, Haplotrema 329, 333 concinna, Nacella 279 conica, Fonscochlea 8, 15, 22, 27, 39-41, 44, 45, 47, 48, 50, 51, 52-54, 82, 83, 85-89, 94, 95, 98, 99, 101, 102, 105, 131-134 Conidae 281 contabulata, Gastrana 290 contectoides, Viviparus 284, 285 contortus, Planorbis 285 Conuber sordida 281 Conus arenatus 281 pennaceus 281 Corbicula fluminalis 293 fluminea 293 Corbiculidae 293 corbis, Cardium 290 Corbula trigona 292 vicaria 292 Corbulidae 292 cordatum, Pleurobema 293 Corillidae 345-352 cornea, Neritodryas 243 corneum, Sphaerium 293, 294 corneus, Planorbis 285 corneus, Solen 290 corona, Clithon 241, 243, 244 coronata, Doto 282 coronata, Facelina 283 corpulenta, Anodonta 293 coruscus, Mytilus 289 Coryphella lineata 283 trilineata 283 Coryphellidae 283 costata, Melanopsis 284, 285 costatus, Strombus 281 Coxiella 103 cracherodii, Haliotis 279 Cranchiidae 295 crassa, Fissurella 279 Crassostrea 200 madrasensis 290 virginica 199, 290 crassus, Unio 293 crebricostata, Venericardia 290 Crenomytilus grayanus 289 INDEX Creseis 264 virgula 282 crinitus, Acanthochiton 214 cristata, Ancula 282 cristata, Armiger 285 cronkhitei, Discus 288 crosseana, Assiminea 243, 244 Cryptochiton stelleri 261 Ctenoglossa 375, 376 cubensis, Byssanodonta 293 Cultellidae 290 Cummingia tellinoides 291 cuneata, Mysella 290, 292 cuneata, Rangia 290 Cuthonidae 283 Cuvierina 264 columella 282 cyanea, Octopus 295 Cyclophoroidea 375, 376 Cyprinidae 363 Cystopeltidae 349-352 Daudebardiidae 349-352 dealbatus, Bulimulus 287 decollata, Cerithidea 281 delesserti, Nacella 279 deltoidalis, Tellina 291 demissa, Geukensia 289 demissus, Modiolus 289 Dendronotidae 282 Dendronotus frondosus 282 subramosus 282 Dendropupidae 349-352 denticulata, Siphonaria 283 denticulatus, Donax 291 dentiens, Ningbingia 157-173; 161-167 depilans, Aplysia 282 depressa, Limapontia 282 depressa, Onchidoris 282 Deroceras 264 caucasicum 287 reticulatum 141-156; 143-148, 150-152, 267, 270, 287 sturanyi 287 despectus, Tergipes 283 Diacria trispinosa 282 diadema, Clithon 243, 244 diaphana, Rissoella 280 Diarca 264 Diastoma varium 281 Diastomidae 281 Dicathias orbita 281 differens, Tomichia 103 Digenea* 188 digitalis, Acmaea 280 dilatata, Elliptio 205, 293 dioica, Urtica* 217-227 dirga, Nagarawa* 2, 91 dirphica, Monacha 353 Discidae 336, 345-348 Discus cronkhitei 288 rotundatus 225, 286 dislocata, Goniobasis catenaria 198, 199, 200, 201 385 Divariscintilla 177, 187, 191, 192; revision of genus, 193 maoria 175, 189-193 troglodytes 175-195; 178-182, 184, 185; 186-187 yoyo 175-195; 177-179, 181, 183-184, 186; 178-185 divisus, Tagelus 291 Docoglossa 374-376 dofleini, Octopus 295 Dolabella auricularia 282 Dolichonephra 328, 344, 348, 352 Donacidae 291 Donax 263 denticulatus 291 gous 291 anleyanus 291 incarnatus 291 semistriatus 291 serra 291 sordidus 291 spiculum 291 trunculus 291 tumida 291 variabilis 291 venustus 291 vittatus 291, 292 Dorcasiidae 341-344 dorsuosa, Acmaea 280 Dosidicus gigas 295, 313, 314, 317, 319- 320, 324 Dosinia angulosa 291 elegans 291 exoleta 291 hepatica 291 japonica 291 Doto amyra 282 coronata 282 kya 282 Dotoidae 282 Dreissena polymorpha 293 Dreisseneidae 289 Dreissenidae 293 duplicatus, Polinices 281 duttoniana, Lithasia 198, 199 eblanae, Todaropsis 318, 322, 324 eburneum, Cerithium 281 Ectenagena 363, 366, 367 Ectobranchia 375, 376 edule, Cardium 290 edule, Cerastoderma 229 edulis, Mytilus 199, 289 edulis, Ostrea 290 Cursor laevigata* 283 Elasmognatha 328, 347 elata, Vestia 286 Eledone cirrhosa 295 moschata 295 elegans, Dosinia 291 elegans, Pomatias 262 Elimia 197 elliptica, Laternula 292 386 INDEX Elliptio complanata 293 dilatata 205, 293 Ellobiacea 251, 252 Ellobiidae 286 Elminius modestus* 229, 234 elodes, Lymnaea 262, 284 Elona 264 quimperiana 287, 288 elongata, Calyptogena (Ectenagena) 367 Elonidae 287 Elysia viridis 282 Elysiidae 282 Endodontidae 286, 345-348, 352 Endodontinia 346 Endodontoidea 344, 348 Endontidae 269 Enidae 286, 336, 341-344, 349-352 Ensis siliqua 290 Enteroxenos 264, 283 bonnevie 281 Entoconchidae 281 Eobania vermiculata 217, 225, 226, 287, 288, 359, 360 Erinna aulacospira 239 newcombi 239 Eubranchidae 283 Eubranchus exiguus 283 olivaceus 283 pallidus 283 rustylus 283 Eucleoteuthis luminosa 317, 320, 324 Eucobresia 264 nivalis 286 Euconulidae 287, 345-348 Euconulus 264 fulvus 287, 288 Euglandina rosea 287, 288 euglypta, Protothaca 291 Euparypha pisana 217, 225, 359 Euprymna scolopes 295 Eurycaelon 197 Euthyneura 334, 375-377 excentricus, Hebetancylus 285 exiguus, Eubranchus 283 exoleta, Dosinia 291 ezonis, Nuttallia 291 fabalis, Sphaerium 293 fabricii, Gonatus 295 Facelina coronata 283 Facelinidae 283 fallax, Gobius* 214 Falsihydrobia streletzkiensis 284, 285 Falsimargarita iris 280 fasciata, Aplysia 282 fasciatus, Liguus 287, 288 Fasciolaridae 281 Felaniella usta 290 felina, Omalonyx 286, 288 Ferrissia 266 noumeensis 244 rivularis 285 sharpi 239 Ferussaciidae 341-344 festivus, Shaskyus 281 Fijidoma maculata 244, 245 Filholiidae 349-352 filippovae, Todaropsis 314 Fissurella barbadensis 279 crassa 279 Fissurellidae 212, 279 Fissurelloidea 375, 376 flavovulta, Trinchesia 283 flavus, Limax 287, 288 Flexoglossata 374 flexuosa, Thyasira 290 floridana, Thala 281 floridensis, Goniobasis 198 fluminalis, Corbicula 293 fluminea, Corbicula 293 fluvialis, lo 198 fluviatilis, Ancylus 285 Fluviopupa 245 brevior 239, 245 pupoidea 244, 245 foliata, Trinchesia 283 Fonscochlea 1, 10, 12-15, 17, 18-19, 25- 26, 90, 96, 101, 105 accepta 8, 15, 18-24, 26-27, 29-30, 32-34, 36-39, 56, 73-79, 74, 75, 77, 82-89, 91, 97-99, 101, 102, 125-130 aquatica 8, 15, 20-24, 27-29, 30-31, 32-34, 34-35, 36, 37-39, 48, 56, 82- 89, 94, 95, 97-102, 105, 125-130 billakalina 8, 20, 21, 27, 38, 39, 45, 46, 48, 49, 48-49, 50, 51, 51, 53-55, 98, 99, 101, 105, 131-134 conica 8, 15, 22, 27, 39-41, 44, 45, 47, 48, 50, 51, 52-54, 82, 83, 85-89, 94, 95, 98, 99, 101, 102, 105, 131- 134 variabilis 8, 15, 20, 21, 23, 27, 38, 39- 41, 42-43, 44, 46, 44-47, 48, 49, 50, 51, 52, 82-89, 94, 98, 99, 101, 102, 105, 131-134 zeidleri 8, 13, 15, 19-24, 32, 55, 56, 57, 58-59, 76-78, 82-89, 91, 94, 95, 96-105, 135-137 Fonscochlea (Wolfgangia) 1, 55, 101 fontinalis, Physa 285 forbesi, Loligo 295 formosa, Hero 283 forskalii, Bulinus 285 fortunei, Limnoperna 293, 294 fragilis, Doto 282 fragilis, Theora 291 frondosus, Dendronotus 282 fruticum, Bradybaena 217, 226, 287, 353, 358-360 fulgurans, Nerita 280 са, Achitina 286 fulvus, Euconulus 287, 288 funebralis, Tegula 280 Fusarium* 328 fuscus, Laevapex 285 fusticula, Nausitora 269 gagates, Milax 287 Galba 266 viridis 239 INDEX Galeomma 190, 191, 193 Galeommatidae 290 gallina, Venus 292 galloprovinciallis, Mytilus 289 Gari kazunensis 291 Gastrana contabulata 290 Gastrodontidae 349-352 Gastrodontoidea 346, 350, 351 Gastropoda 376 Gemma gemma 291 gemma, Gemma 291 generosa, Panope 292 Geomalacus 264, 269 Geophila 328, 342, 346, 350 georgianus, Viviparus 217, 284, 285 Geukensia demissa 289 gibbosa, Anodonta 293 gibbosa, Cavolinia 282 Gibbula umbilicalis 280 gibbus, Argopecten 289 gigas, Dosidicus 295, 313, 314, 317, 319- 320, 324 gigas, Siphonaria 229-236; 231 gigas, Strombus 281 glabrata, Biomphalaria 285, 329, 333, 336 Glacidorboidea 375, 376 glaucum, Cerastoderma 290 globosus, Bulinus 285 Glycymeridae 289 Glycymeris yessoensis 289 Gobius fallax* 214 Gonatidae 295 Gonatus fabricii 295 Goniobasis 197 acutocarinata 198, 199 alabamensis 198, 199 catenaria 201 catenaria dislocata 198, 199, 200, 201 floridensis 198 laqueata 197, 198 livescens 197, 198 proxima 197, 198, 200, 201 simplex 198 Goniodorididae 282 Goniodoris nodosa 282 gouldi, Bankia 292 gouldi, Terebra 282 gouldii, Donax granatina, Patella 279 grandis, Anodonta 205 granifera, Tarebia 241, 242 granosa, Neritina 239, 245, 284, 285 granularis, Patella 279 grata, Cellana 279 grayanus, Crenomytilus 289 groenlandicus, Serripes 290 guadeloupensis, Biomphalaria 329 Gyraulus 249, 266 montrouzieri 244 na, Physa 285 aifaensis, Monacha 287 hainanensis, Brotia 284 haldemani, Acella 284 Haliotidae 212, 279 Haliotis cracherodii 279 387 iris 279 laevigata 279 ruber 279 rufescens 279 tubercolata 214 tuberculata 279 Haliotoidea 375, 376 Halodule wrighti 177, 186 Haminea hydatis 284 Hancockia californica 282 Hancockiidae 282 hanleyanus, Donax 291 Haplotrema 327, 332, 334, 336, 337 concavum 329, 333 Haplotrematidae 327, 335, 338, 341-344 hawaïiensis, Nototodarus 318, 323 Hebetancylus excentricus 285 Helicacea 347, 349, 351 Helicarionidae 269, 345-348, 352 Helicella 266 caperata 287 Helicellidae 349-352 Helicida 347, 351 Helicidae 287, 349-352 Helicina 327, 334, 336, 337 orbiculata 329, 330, 333 Helicinidae 212 Helicinoidea 376 helicinus, Margarites 280, 283 Helicodiscidae 345-348 Helicodontidae 349-352 Helicodontoidea 350 Helicoida 374 Helicoidea 344, 346, 348, 350-352 Helisoma 266 trivolvis 217, 285 Helix aspersa 217, 225, 287 lucorum 217-227, 287, 353, 358-360 pomatia 287, 360 Helixarionoidea 328, 347, 351 Helixina 328, 342, 346, 350 Helixinia 346, 350 Helminthoglypta arrosa 287 Helminthoglyptidae 287, 349-352 helveticus, Oxychilus 286 Hemistomia 26, 90 caledonica 245 hemphilli, Juga 198, 199 hepatica, Dosinia 291 Hero formosa 283 Heroidae 283 Heterocyclus petiti 64 Heteroglossa 377 Heterosquilla tricarinata* 175 Heterurethra 328, 347 Hiatella byssifera 292 Hiatellidae 292 hibernicum, Pisidium 293 hierosolyma Laevantina 287, 288 hispida, Trichia 288 Holopoda 327, 328, 347, 349, 351 Holopodopes 327-329, 341, 343, 345, 347 hombergi, Tritonia 282 hopetonensis, Triodopsis 329, 333 hopetonensis, Triodopsis fallax 329 388 INDEX Horatia nelsonensis 64 Horatia-Pseudamnicola complex 64 hortensis, Arion 286 Hot-Vent group A 375, 376 Hot-Vent group C 376 Humboldianidae 349-352 hupensis, Oncomelania 329, 333 hyadesi, Martialia 318, 323 Hyaloteuthis 324 pelagica 313, 317, 321, 324 hydatis, Haminea 284 Hydrobia 96, 103, 104, 266, 285 acuta 284 pusilla 284 totteni 104 ulvae 104, 284 ventrosa 284 Hydrobiidae 245, 284 Hydrocenoidea 376 Hygromia striolata 225 Hygromiidae 349-352 Hygrophila 251 hypnorum, Aplexa 285 illecebrosus, Illex 295 Illex 313, 324 coindetti 318, 321, 324 illecebrosus 295 oxygonius 318, 321-322 Illicinae 324 llyanassa 200 obsoleta 199 imbecilis, Anodonta 293 incarnatus, Donax 291 inflata, Limacina 282 inflata, Trochidrobia 8, 27, 61, 62, 67, 68, 69, 70-71, 72, 73, 99, 105, 138- 140 inflectus, Mesodon 329, 333 insessa, Acmaea 280, 283 insignis, Acila 289 integra, Physa 285 intermedius, Arion 286 lo 197 fluvialis 198 iris, Falsimargarita 280 iris, Haliotis 279 irradians, Argopecten 269, 289 islandica, Arctica 291 islandica, Chlamys 289 japonica, Dosinia 291 japonica, Mya 292 japonica, Nerita 280 japonica, Venerupis 291 japonicum, Argopecten 289 japonicum, Musculium 293 Jardaniella thaanumi 64 jedoensis, Protothaca 291 jeffreysiana, Vascionella 189 jenkinsi, Potamopyrgus 284 Jorunna tomentosa 283 joubini, Octopus 295 Juga 197 hemphilli 198, 199 juliana, Aplysia 282 Katelysia opima 291 kazunensis, Gari 291 keenae, Septifer 289 Keenocardium californiese 290 Kellia 191 suborbicularis 192 Kentrodorididae 283 kilmeri, Calyptogena (Archivesica) 367 kirki, Pupa 282 kotulai, Semilimax 286 krustensterni, Solen 290 kurodai, Aplysia 282 kya, Doto 282 labiosa, Neritina 243, 245 Lactuca sativa* 217-227 Lacuna 264 pallidula 280 vincta 280 Lacunidae 280 lacustre, Musculium 293 lacustris, Ancylus 285 Laevapex fuscus 285 laevigata, Egregia* 283 laevigata, Haliotis 279 laevis, Agriolimax 225 lagunae, Trinchesia 283 lamellosa, Nucella 281 laminata, Cochlodina 286 Lampsilis anodontoides 293 ovata 293 radiata siliquoidea 205-210 recta 293 siliquoidea 293 lapillus, Thais 281 laqueata, Goniobasis 197 Lasaea rubra 290, 292 lateralis, Mulinia 290 Laternula elliptica 292 Laternulidae 292 Latiidae 249, 250, 252-254 latior, Mesomphix 329, 333 latipes, Phreatomerus* 2, 91 Latirolagena smaragdula 281 latistrigata, Patelloida 280 laxa, Melanoides 241, 242 leachi, Bithynia 284 leonia, Melibe 282 Lepetelloidea 375, 376 Lepetodriloidea 375, 376 Leptoxis 197 carinata 217, 284 praerosa 198 (Mudalia) carinata 198 lessoni, Siphonaria 283 Levantina hierosolyma 287, 288 Liguus fasciatus 287, 288 lilljeborgi, Pisidium 293 Limacacea 328, 345, 347, 351 Limacia clavigera 283 Limacidae 287, 345-352 Limacina 264 bulimoides 282 inflata 282 trochiformis 282 Limacinidae 282 Limacoidea 328, 347, 350, 351 INDEX Limapontia capitata 282 depressa 282 senestra 282 Limapontiidae 282 limatula, Yoldia 289 Limax 264 flavus 287, 288 maximus 287, 288 Limaxina 346, 350 Limaxinia 346, 350 Limnoperna fortunei 293, 294 limosa, Amnicola 284 lineata, Coryphella 283 lineata, Monodonta 280 lineata, Septaria 241, 243, 244 lineatus, Mytilaster 289 Lithasia 197 duttoniana 198, 199 verrucosa 198 litoralis, Macoma 290 littorea, Littorina 280 Littorina 263 acutispira 267, 270, 280 coccinea 280 littorea 280 neglecta 267, 280 nigrolineata 280 obtusata 280 rudis 280 scabra 280 sitkana 280 Littorinidae 280 livescens, Goniobasis 197, 198 Loliginidae 295, 313 Loligo forbesi 295 opalescens 295 pealei 295 vulgaris 295 longicosta, Patella 279 longipes, Ceratobornia 192 lubrica, Cadella 290 Lucinidae 290 lucorum, Helix 217-227, 287, 353, 358-360 luhuanus, Strombus 281 luminosa, Eucleoteuthis 317, 320, 324 lutosa, Melanoides 244 lutosum, Cerithium 281 Lymnaea elodes 262, 284 natalensis 284 palustris 217, 285 peregra 285 stagnalis 285 trunculata 285 Lymnaeacea 249-257 Lymnaeidae 249, 250, 252-254, 284 Lysiosquilla® 187, 193 scabricauda* 175, 177, 186 Iysiosquillina, Phlyctaenachlamys 191 macgillvrayi, Neritina 241, 243, 244 Macoma balthica 290 calcarea 290 litoralis 290 middendorffi 290 macrocephala, Septaria 243-245 Macrocyclidae 341-344 macromphalus, Nautilus 297, 308 Mactra sulcataria 290 Mactridae 290 maculata, Fijidoma 244, 245 maculata, Triopha 283 madrasensis, Crassostrea 290 magellanicus, Placopecten 290 magnifica, Calyptogena 291, 292 major, Callianassa 192 malanisica, Neritina labiosa 243, 245 malleatus, Viviparus 284 Malletiidae 289 maoria, Divariscintilla 175, 189-193 Margarites helicinus 280, 283 Margaritifera margaritifera 293, 294 margaritifera, Margaritifera 293, 294 marginata, Archachatina 286 martensii, Pinctada 289 Martialia 324 hyadesi 318, 323 maximus, Limax 287, 288 maximus, Pecten 289 maya, Octopus 295 Megalobulimidae 344-352 megalops, Teuthowenia 295 Megaspiridae 341-344 a: 349-352 Melampus 286, 288 Melanodrymia 376 Melanoides 239 arthurii 242, 244 aspirans 244 laxa 241, 242 lutosa 244 peregrina 241, 242 plicaria 244 tuberculata 239-242, 244, 245, 284, 285 Melanopsis 285 costata 284, 285 Melibe leonia 282 Mercenaria 200 mercenaria 199,291 stimpsoni 291 mercenaria, Mercenaria 199, 291 mercenaria, Venus 292 meridionalis, Notovolva 289 Mesodesma ventricosum 290 Mesodesmatidae 290 Mesodon 327 inflectus 329, 333 normalis 329, 333 roemeri 287 Mesodontidae 345-348 Mesodontoidea 328, 347, 351 Mesogastropoda 327-352, 377 Mesomphix 327, 332, 334, 336, 337 latior 329 messenica, Monacha 353 Mesurethra 328, 341, 343 middendorffi, Macoma 290 Milacidae 287, 345-348 389 390 INDEX Milax 264 budapestensis 287 gagates 287 sowerbii 287 minima, Anodonta 293 minuta, Nuculana 289 minuta, Trochidrobia 8, 27, 61, 62, 66- 68, 67, 69-73, 98, 99, 138-140 Mitridae 281 modestus, Elminius* 229, 234 modioliforma, Calyptogena (Ectenagena) 367 Modiolus demissus 289 modiolus 289, 292 modiolus, Modiolus 289, 292 Modulidae 281 Modulus modulus 281, 283 modulus, Modulus 281, 283 Mollusca 259-295 Monacha 264, 266 beieri 353 cartusiana 287, 353-362 dirphica 353 haifaensis 287 messenica 353 Monodonta lineata 280 Montacuta 192 substriata 192 Montacutidae 290 Montacutona 191 Montfortula rugosa 279 montrouzieri, Gyraulus 244 Morula musiva 281 moschata, Eledone 295 Mudalia 198 lateralis 290 muricata, Onchidoris 283 muscarum, Cerithium 281 Musculium 294 japonicum 293 lacustre 293 partumeium 293 securis 293 transversum 293 musiva, Morula 281 mustelina, Achatinella 286, 288 Mya 265 arenaria 292 japonica 292 priapus 292 truncata 292 Myidae 292 myosotis, Ovatella 286, 288 ysella 192, 270 bidentata 290, 292 cuneata 290, 292 planulata 290, 292 Mytilaster lineatus 289 Mytilidae 289, 293 one sallei 289 ytilus 200 californiensis 289 coruscus 289 edulis 199 edulis 289 galloprovinciallis 289 variabilis 289 Nacella concinna 279 delesserti 279 Nacelloidea 375, 376 Nagarawa dirga* 2, 91 napierana, Amplirhagada 287 Nassariidae 281 Nassarius reticulatus 281 nasuta, Physastra 241, 243-245 nasutus, Bulinus 285 natalensis, Lymnaea 284 Naticidae 281 Nausitora fusticula 269 Nautilidae 295 Nautiloidea 295 Nautilus 263, 265, 267, 268 belauensis 297-312; 299, 300, 302, 306, 307, 309 macromphalus 297, 308 pompilius 295, 297-312; 299, 300, 302, 306, 307, 309 pompilius suluensis 298 repertus 297 scrobiculatus 297, 308 stenomphalus 297 navalis, Teredo 292 neglecta, Littorina 267,280 neglectus, Clithon 239 nelsonensis, Horatia 64 nemoralis, Cepaea 226, 287 Neohelix 327 albolabris 329, 333 Neomphalida 375 Neomphaloidea 375, 376 Neotaenioglossa 334, 375-377 Neptunea antiqua 281 Nerita 244 albicilla 280 atramentosa 280 fulgurans 280 japonica 280 polita 280 tesselata 280 versicolor 280 Neritidae 212, 214, 237, 240, 242-243, 280, 284 Neritilia 244 rubida 243, 244 Neritimorpha 334, 375, 376 Neritina 244, 245 asperulata 242, 245 auriculata 242, 244 canalis 242, 244 ranosa 239, 245, 284, 285 abiosa malanisica 243, 245 macgillvrayi 241, 243, 244 petiti 242, 244, 245 porcata 242, 244 pulligera 241, 242, 244 squamipicta 241, 242, 244 turrita 241, 242, 244 turtoni 244 variegata 241, 242, 244 vespertina 239 INDEX 391 Neritodryas Omalgyra atomus 280 cornea 243 Omalogyra 267, 283 subsulcata 241, 243, 244 Omalogyridae 280, 374-376 Neritoidea 376 Omalonyx 264 newcombi, Erinna 239 felina 286, 288 nigrolineata, Littorina 280 omissa, Cavatidens 290 niloticus, Trochus 280 Ommastrephes bartramii 315-316, 317, 324 Ningbingia dentiens 157-173; 161-167 Ommastrephidae 295, 313-326 nitens, Aegopinella 286 Ommastrephinae 315, 324 nitidula, Aegopinella 286, 288 Onchidorididae 282 Nitocris 197 Onchidoris nivalis, Eucobresia 286 bilamellata 282, 284 nodosus, Chromodoris 283 depressa 282 nodosus, Goniodoris 282 muricata 283 normalis, Mesodon 329, 333 pusilla 283 Notacmea Oncomelania 103, 104, 327, 332, 334, 336, petterdi 280 337 scutum 280 hupensis 329, 333 Nototodarus 324 Oopeltidae 349-352 hawaliensis 318, 323 Opacinacola 64 sloanii 318, 322-324 opalescens, Loligo 295 Notovola meridionalis 289 opalina, Rissoella 280 noumeensis, Ferrissia 244 opercularis, Chlamys 289 Nucella lamellosa 281 opima, Katelysia 291 Nuclanidae 289 Opisthobranchia 282, 377 nucleolus, Clithon 243, 245 orbiculata, Helicina 329, 330, 333 nucleus, Nucula 289 orbita, Dicathias 28° Nucula Orculidae 341-344 annulata 289 orcutti, Chlamydoconcha 191 nucleus 289 Oreohelicidae 349-352 sulcata 289 Ornithoteuthis 315, 324 turgida 289 antillarum 314, 317, 320-321, 324 Nuculana Orthalicidae 345-348, 352 minuta 289 Orthalicoidea 328, 347 pernula 289 Orthurethra 328, 341, 343, 344, 351 Nuculidae 289 Ostrea edulis 290 Nuttallia Ostreidae 290 ezonis 291 Otoconchidae 345-348 olivacea 291 oualaniensis, Clithon 243, 244 nuttallii, Clinocardium 229, 290 oualaniensis, Sthenoteuthis 317, 319, 324 obesus, Thunnus* 320 ovalis, Succinea 286 obsoleta, Ilyanassa 199 ovata, Abra 291 obtusa, Retusa 282, 284 ovata, Lampsilis 293 obtusata, Littorina 280 Ovatella 288 occidentale, Sphaerium 293 myosotis 286, 288 Ocenebra poulsoni 281 oweniana, Sepietta 295 Octopodidae 295, 313 Oxychilus 264 Octopus cellarius 286 briareus 295 helveticus 286 cyanea 295 oxygonius, Шех 318, 321-322 ofleini 295 pacifica, Calyptogena 367 joubini 295 pacifica, Rossia 295 maya 295 pacificus, Todarodes 295, 318, 322 tetricus 295 pallidula, Lacuna 280 vulgaris 295 pallidus, Eubranchus 283 oculus, Patella 279 palustris, Lymnaea 217, 285 Odontostomidae 345-348 Pandora pulchella 292 Oegopsida 313-326 Pandoridae 292 officinalis, Sepia 295 Panope generosa 292 Oleacinacea 345, 347 Рапореа 265 | Oleacinidae 287, 345-348, 352 papilosa, Aeolidia 283 Oleacinina 342, 346 paradigitalis, Acmaea 280 Oleacinoidea 343, 347 Paraphantidae 341-344 olivacea, Nuttallia 291 Parmacella 264 olivaceus, Clithon 243, 244 rutellum 287 olivaceus, Eubranchus 283 Parmacellidae 287, 345-352 392 INDEX Partulidae 341-344 Partuloidea 343, 344 partumeium, Мизсийит 293 partumeium, Sphaerium 293 parva, Rissoa 267, 280 Patella 235 aspersa 279 cochlear 279 granatina 279 ranularis 279 ongicosta 279 oculus 279 vulgata 230, 279 Patellidae 212 Patelloida alticostata 280 latistrigata 280 Patelloidea 375, 376 Patina 264 pellucida 279 Patinopecten caurinus 289 yessoensis 289 patula, Siliqua 290 pealei, Loligo 295 Pecten maximus 289 Pectinidae 289 peggyae, Anodonta 293 pelagica, Hyaloteuthis 313, 317, 321, 324 pellucida, Patina 279 pellucida, Vitrina 286 pelta, Acmaea 280 pennaceus, Conus 281 Pentaganglionata 375-376 peregra, Lymnaea 285 peregrina, Melanoides 241, 242 Perna viridis 289, 292 pernula, Nuculana 289 Peronidia venulosa 290 zyonoensis 291 Petasites albus* 217-227 petiti, Heterocyclus 64 petiti, Neritina 242, 244, 245 petterdi, Notacmea 280 pfeifferi, Biomphalaria 285 Philline aperta 284 phillippinarum, Tapes 291 Philomycidae 345-348 Phlyctaenachlamys 191-193 lysiosquillina 191 Phreatomerus latipes* 2, 91 Phyllaplysia taylori 282 Physa acuta 285 fontinalis 285 gyrina 285 integra 285 virgata 285 Physastra 241 nasuta 241, 243-245 Physella 266 Physidae 249, 250, 252-254, 285 pictorum, Unio 293 pilosa, Acanthodoris 282 Pinctada martensii 289 vulgaris 289 Pinna atropurpura 289 atropurpurea 265 bicolor 265 Pinnidae 289 pisana, Euparypha 217, 225, 359 pisana, Theba 270, 287 piscinalis, Anodonta 293 Pisidium 266, 294 amnicum 293 annandalei 293 casertanum 293 clarkeanum 293, 294 compressum 293 hibernicum 293 lilljeborgi 293 variabile 293 Placopecten magellanicus 290 plana, Scrobicularia 225, 291 Planorbidae 211, 237, 240, 243, 245, 249, 252-254, 285 Planorbis 266 albus 285 carinatus 285 contortus 285 corneus 285 planorbis 285 vertex 285 planorbis, Planorbis 285 planorbis, Skeneopsis 280 planulata, Mysella 290, 292 Platyhelminthes 374 Plectopylidae 345-348 Plectopyloidea 347, 351 Pleurobema coccineum 293 cordatum 293 Pleurocera 197 acuta 198 canaliculatum 198 unciale 199 Pleuroceridae 284 Pleurodiscidae 341-344, 352 Pleurodontidae 287 Pleurotomarioidea 375, 376 plicaria, Melanoides 244 plicata, Amblema 293 Plycera quadrilineata 283 Polinices duplicatus 281 polita, Nerita 280 Polyceridae 283 Polygyra thyroideus 287 Polygyracea 328, 345, 347, 351 Polygyridae 287, 327, 332, 334-338, 345- 352 Polygyrinae 338 polymorpha, Dreissena 293 Polyplacophora 214 pomatia, Helix 287, 360 Pomatias elegans 262 Pomatiopsis 103, 104 pompilius, Nautilus 295, 297-312; 299, 300, 302, 306, 307, 309 INDEX ponderosa, Calyptogena (Calyptogena) 366, 367 porcata, Neritina 242, 244 porcellana, Septaria 241, 243, 244 Posticobia 64 Potamididae 281 Potamocorbula amurensis 292 Potamopyrgus 103, 104, 266 antipodarum 284 jenkinsi 284 poulsoni, Ocenebra 281 praerosa, Leptoxis 198 priapus, Mya 292 Prionoglossa 376 pritchardi, Clithon 243-245 producta, Pseudisidora 239 profunda, Allogona 287 prophetarum, Sphincterochila 287, 288 Prosobranchia 211-216, 279, 284 Protothaca euglypta 291 jedoensis 291 staminea 291 proxima, Adalaria 282 proxima, Goniobasis 197, 198, 200, 201 Psammobidae 291 Pseudamnicola 266; see also Horatia Pseudisidora producta 239 rubella 239 pseudoargus, Archidoris 283 Pseudopythina 191 Pteriidae 289 pteropus, Sthenoteuthis 316, 317, 324, 325 pulchella, Pandora 292 pulligera, Neritina 241, 242, 244 Pulmonata 217-227, 229-236, 283, 284, 334, 335, 374 punctata, Aplysia 282 Punctidae 345-348, 352 Punctoidea 342, 346, 351 Punctum 267 pygmaeum 286, 288 punicea, Trochidrobia 8, 15, 27, 48, 56, 60-63, 64, 64-65, 65, 68-73, 79-82, 80, 81, 82-84, 88, 89, 96, 98, 102, 105, 138-140 Pupa kirki 282 Pupillacea 341, 343 Pupillidae 341-344, 352 Pupillina 328, 342, 346, 350 Pupilloidea 342, 343, 344 pupoidea, Fluviopupa 244, 245 pusilla, Hydrobia 284 pusilla, Onchidoris 283 pusilla, Vertigo 286 pygmaeum, Punctum 286, 288 pyramidata, Clio 282 Pyramidellidae 373 Pyramidelloidea 375, 376 Pyramidulidae 341-344 quadrilineata, Plycera 283 Quadrula 293 quimperiana, Elona 287, 288 radiata, Cellana 279 radiata, Lampsilis 205-210 393 Radix 266 Rangia cuneata 290 rarispina, Clithon 244 recta, Lampsilis 293 repertus, Nautilus 297 reticulatum, Deroceras 141-156; 143-148, 150-152, 287 reticulatus, Agriolimax 217 reticulatus, Deroceras 267, 270 reticulatus, Nassarius 281 retifera, Rhamphidonta 192 Retusa obtusa 282, 284 Retusidae 282 Rhamphidonta 192 retifera 192 rhodostoma, Bullia 281 Rhytidacea 341, 343 Rhytididae 341-344, 352 Rhytidoidea 342, 343, 350, 351 Risoella 283 Rissoa 270 parva 267, 280 splendida 280 Rissoella 267 diaphana 280 opalina 280 Rissoellidae 280 Rissoelloidea 375, 376 Rissoidae 280 rivicola, Sphaerium 293 rivularis, Ferrissia 285 robusta, Sepiola 295 roemeri, Mesodon 287 rosea, Euglandina 287, 288 Rossia pacifica 295 rotundatus, Discus 225, 286 rubella, Pseudisidora 239 ruber, Haliotis 279 rubida, Neritilia 243, 244 rubra, Lasaea 290, 292 rudis, Littorina 280 rufescens, Haliotis 279 rufum, Campeloma 284 rufus, Arion 217 rugosa, Montfortula 279 rupestre, Cerithium 281 rustylus, Eubranchus 283 rutellum, Parmacella 287 Sacoglossa 268 Sagdidae 345-348 Sagdoidea 346, 347, 350 sagittatus, Todarodes 318, 322 sallei, Mytilopsis 289 sanguisuga, Septaria 241, 243, 244 sativa, Lactuca* 217-227 scabra, Acmaea 280 scabra, Littorina 280 scabra, Thiara 242, 244 scabricauda, Lysiosquilla® 175, 177, 186 scabridum, Cerithium 270, 281 scabridum, Cerithium 281 Scissurelloidea 375, 376 scolopes, Euprymna 295 Scrobicularia plana 225, 291 Scrobiculariidae 291 scrobiculatus, Nautilus 297, 308 394 INDEX Sculptariidae 349-352 scutum, Notacmea 280 securis, Musculium 293 Segmentina 266 Seguenziida 375, 376 Seguenzioidea 375, 376 Semelidae 291 Semilimax 264 kotulai 286 Semisalsa 266 semistriatus, Donax 291 senestra, Limapontia 282 Senilia senilis 289 senilis, Senilia 289 Sepia officinalis 295 Sepietta oweniana 295 Sepiidae 295, 313 Sepiola robusta 295 sepiola, Sepioteuthis 295 Sepiolidae 295 Sepioteuthis sepiola 295 Septaria 245 lineata 241, 243, 244 macrocephala 243-245 porcellana 241, 243, 244 sanguisuga 241, 243, 244 suffreni 243-245 Septifer keenae 289 serra, Donax 291 Serripes groenlandicus 290 setosus, Turbo 280 sharpi, Ferrissia 239 Shaskyus festivus 281 Sigmurethra 328, 341, 343, 345, 347, 349, 351 Siliqua alta 290 patula 290 siliqua, Ensis 290 siliquoidea, Lampsilis 293 siliquoidea, Lampsilis radiata 205-210 simile, Sphaerium 293, 294 similis, Solatopupa 286 simplex, Goniobasis 198 simulata, Trochoidea 288 Siphonaria 229, 235 denticulata 283 igas 229-236; 231 essoni 283 virgulata 283 Siphonariidae 283 sitkana, Littorina 280 Skeneopsidae 280 Skeneopsis 267, 283 planorbis 280 sloanii, Nototodarus 318, 322-324 smaragdula, Latirolagena 281 smithi, Trochidrobia 8, 27, 60-63, 65-66, 68-73, 81, 82, 98, 105, 138-140 Solaropsidae 349-352 Solatopupa similis 286 Solecurtidae 291 Solen corneus 290 krustensterni 290 Solenidae 290 solidissima, Spisula 290 solidum, Sphaerium 293 sordida, Conuber 281 sordidus, Donax 291 sowerbii, Milax 287 speciosa, Tricolia 211-216; 213 Sphaeriidae 293, 294 Sphaerium 294 corneum 293, 294 fabalis 293 occidentale 293 partumeium 293 rivicola 293 simile 293, 294 solidum 293 striatinum 293 transversum 293, 294 Sphincterochila prophetarum 287, 288 zonata 287, 288 Sphincterochilidae 287, 349-352 Sphincterochiloidea 350 spiculum, Donax 291 spinosus, Clithon 243 Spiraxidae 341-344 Spirula spirula 295 spirula, Spirula 295 Spirulidae 295 Spisula solidissima 290 voyi 290 splendida, Rissoa 280 squamipicta, Neritina 241, 242, 244 squamosa, Anomalocardia 291 stagnalis, Lymnaea 285 Stagnicola 266 staminea, Protothaca 291 stelleri, Cryptochiton 261 Stenoglossa 375, 376 Stenogyridae 349-352 stenomphalus, Nautilus 297 Sthenoteuthis oualaniensis 317, 319, 324 pteropus 316, 317, 324, 325 stimpsoni, Mercenaria 291 Stomatellidae 212 streletzkiensis, Falsihydrobia 284, 285 Streptaxacea 341 Streptaxidae 341-344 Streptaxoidea 342, 343 Streptoneura 376 striatinum, Sphaerium 293 striatula, Venus 292 striolata, Hygromia 225 Strobilopsidae 341-344 Strombidae 281 Strombus costatus 281 gigas 281 uhuanus 281 Strophocheilacea 341, 343 Strophocheilidae 341-344, 349-352 stultorum, Tivela 291 sturanyi, Deroceras 287 Stylommatophora 217-227, 327-352 subcylindraceus, Anatontoides 293 INDEX 395 subfuscus, Arion 286 Thiara suborbicularis, Kellia 192 amarula 242, 244 subramosus, Dendronotus 282 bellicosa 244 substriata, Montacuta 192 cancellata 242 subsulcata, Neritodryas 241, 243, 244 scabra 242, 244 Subulinidae 341-344, 349-352 terpsichore 244 Subulinoidea 342, 350 Thiaridae 237, 240, 242, 245, 284 Succinacea 328 Thunnus obesus* 320 Succinea 266 Thyasira flexuosa 290 ovalis 286 Thyasiridae 290 Succineacea 345 Thyonicola* 264 Succineida 328, 346 americana* 283 Succineidae 286, 328, 345-348 thyroideus, Polygyra 287 Succinoidea 347 Thyrophorellidae 345-348 suffreni, Septaria 243-245 Thyrophorelloidea 346 sulcata, Nucula 289 Thysanophoridae 349-352 sulcataria, Mactra 290 Tindria callistiformis 289, 292 suluensis, Nautilus pompilius 298 Titiscanioidea 376 swifti, Swiftopecten 290 Tivela stultorum 291 Swiftopecten swifti 290 Todarodes 313, 324 Symplectoteuthis 324 pacificus 318, 322 Systrophiidae 341-344 sagittatus 318, 322 Tagelus divisus 291 Todarodinae 322 Tantulum 266 Todaropsis Tapes phillippinarum 291 eblanae 318, 322, 324 Taradodes pacificus 295 filippovae 314 Tarebia granifera 241, 242 tomentosa, Jorunna 283 tasmanica, Valvatasma 64 Tomichia 5, 103 taylori, Phyllaplysia 282 differens 103 Tegula funebralis 280 Tornatellididae 341-344 Tellina Tornatellinidae 336 alternata 291 totteni, Hydrobia 104 deltoidalis 291 tramoserica, Cellana 279 tenuis 291 transversum, Musculium 293 Tellinidae 290 transversum, Sphaerium 293, 294 tellinoides, Cummingia 291 Trematoda* 188 tentaculata, Bithynia 284, 285 Tresus capax 290 tenuis, Tellina 291 tricarinata, Heterosquilla* 175 Terebra gouldi 282 Trichia hispida 288 Terebridae 282 Trichotropidae 281 Teredinidae 264, 292 Trichotropis cancellatum 281 Teredo 292 Tricolia speciosa 211-216; 213 bartschi 292 tridentatum, Carychium 286, 288 navalis 292 Trifongonia verrucosa 293 Tergipes despectus 283 trigona, Corbula 292 terpsichore, Thiara 244 Trigonochlamydidae 345-348 tesselata, Nerita 280 Trigonochlamydinia 346 Testacella 264, 269, 287 Trigonochlamydoidea 346, 347 Testacellacea 347 trilineata, Coryphella 283 Testacellidae 287, 345-348 Trinehesia Testacelloidea 342, 346 abronia 283 Tethyidae 282 albocrusta 283 tetricus, Octopus 295 amoena 283 Teuthoidea 313-326 flavovulta 283 Teuthowenia megalops 295 foliata 283 thaanumi, Jardaniella 64 lagunae 283 Thaididae 281 Triodopsis 327, 329 Thais fallax hopetonensis 329 clavigera 281 hopetonensis 329, 333 lapillus 281 ’ Triopha maculata 283 Thala floridana 281 Triophidae 283 Theba 266 trispinosa, Diacria 282 pisana 270, 287 Tritonia hombergi 282 Theora fragilis 291 Tritoniidae 282 thermica, Bathymodiolous 292 trivolvis, Helisoma 217, 285 thermophila, Bathymodiolous 289 Trochidae 212, 280 396 INDEX Trochidrobia 1, 10, 12-15, 17, 59-61, 64, 90, 96 inflata 8, 27, 61, 62, 67, 68, 69, 70- 71, 72, 73, 99, 105, 138-140 minuta 8, 27, 61, 62, 66-68, 67, 69- 73, 98, 99, 138-140 punicea 8, 15, 27, 48, 59, 60-63, 64, 64-65, 65, 68-73, 79, 82-84, 88, 89, 96, 98, 102, 105, 138-140 smithi 8, 27, 60-63, 65-66, 68-73, 81, 82, 98, 105, 138-140 trochiformis, Limacina 282 Trochoidea 375, 376 Trochoidea 266 simulata 288 Trochomorphidae 345-348 Trochus niloticus 280 troglodytes, Divariscintilla 175-195; 178- 182, 184, 185; 186-187 truncata, Mya 292 Truncatella 328 trunculata, Lymnaea 285 trunculus, Donax 291 tubercolata, Haliotis 214, 279 tuberculata, Melanoides 239-242, 244, 245, 284, 285 tumida, Donax 291 tumidus, Unio 293 Turbidae 280 turbinellus, Vasum 281 Turbo setosus 280 turgida, Nucula 289 turrita, Neritina 241, 242, 244 turtoni, Neritina 244 ulvae, Hydrobia 104, 284 umbilicalis, Gibbula 280 unciale, Pleurocera 199 Ungulinidae 290 unifasciata, Barleeia 280 Unio crassus 293 pictorum 293 tumidus 293 Unionidae 293 Urocoptidae 345-348 Urocyclidae 345-348 Urosalpinx cinerea 281 Urtica dioica* 217-227 usta, Felaniella 290 Vaginulus 264 borellianus 286, 288 valdiviae, Calyptogena (Calyptogena) 366 Valloniidae 341-344, 352 Valvata 266 Valvatasma tasmanica 64 Valvatidae 373 Valvatoidea 375, 376 varia, Chlamys 289 variabile, Pisidium 293 variabilis, Brachiodontes 289 variabilis, Donax 291 variabilis, Fonscochlea 8, 20, 21, 23, 27, 38, 39-41, 42-43, 44, 46, 44-47, 48, 49, 50, 51, 52-54, 82-89, 94, 98, 99, 101, 102, 131-134 variabilis, Mytilus 289 variegata, Neritina 241, 242, 244 varium, Diastoma 281 Vascionella 189, 190 jeffreysiana 189 Vasidae 281 Vasum turbinellus 281 Venericardia crebricostata 290 Veneridae 291 Venerupis japonica 291 ventricosum, Mesodesma 290 Ventridens 327, 332, 334, 336, 337 cerinoideus 329, 333 ventrosa, Hydrobia 284 venulosa, Peronidia 290 Venus gallina 292 mercenaria 292 striatula 292 venusta, Aniscorbula 292 venustus, Donax 291 vermiculata, Eobania 217, 225, 226, 287, 288, 359, 360 Veronicella ameghini 286, 288 Veronicellidae 286 verrucosa, Lithasia 198 verrucosa, Trifongonia 293 versicolor, Nerita 280 vertex, Planorbis 285 Vertiginidae 286, 341-344 Vertigo 267 pusilla 286 Vesicomya 365 Vesicomyidae 291, 363-370 vespertina, Neritina 239 vestalis, Xeropicta 288 Vestia elata 286 Vetigastropoda 375, 376 vicaria, Corbula 292 vincta, Lacuna 280 vindobonensis, Cepaea 353 vinosa, Austropelpa 284 virgata, Cernuella 287, 288, 359 virginica, Crassostrea 199, 290 virgula, Creseis 282 virgulata, Siphonaria 283 virıdis, Elysia 282 viridis, Galba 239 viridis, Perna 289, 292 Vitrina 264 alaskana 286 pellucida 286 Vitrinidae 286, 345-348 Vitrinoidea 328, 346, 347, 351 vittatus, Donax 291, 292 Viviparidae 284 Viviparina 375 Viviparoidea 376 Viviparus 266 ater 284 contectoides 284, 285 georgianus 217, 284, 285 malleatus 284 viviparus 266, 284 viviparus, Viviviparus 266, 284 vortex, Anisus 285 voyi, Spisula 290 INDEX vulgaris, Loligo 295 vulgaris, Octopus 295 vulgaris, Pinctada 289 vulgata, Patella 230, 279 Е 1,55, 10] woodiana, Anodonta 293 wrightii, Halodule* 177, 186 Xanthonychidae 349-352 Xeropicta 266 arenosa 288, 359 vestalis 288 Xolotrema 329 yessoensis, Glycymeris 289 yessoensis, Patinopecten 289 397 Yoldia limatula 289 yoyo, Divariscintilla 175-195; 177-179, 181, 183-184, 186; 178-185 zebra, Chromodoris 283 zeidleri, Fonscochlea 8, 13, 15, 19-24, 32, 55, 56, 57, 58-59, 76-78, 82-89, 91, 94, 95, 96-105, 135-137 zonata, Sphincterochila 287, 288 Zonitidae 286, 327, 345-352 Zonitidea 335 Zonitinia 346, 350 Zonitoidea 328, 346, 348, 350 zyonoensis, Peronidia 291 MALACOLOGIA, VOL. 31 CONTENTS ROBERT C. BAILEY Habitat Selection by a Freshwater Mussel: An Experimental Test RÜDIGER BIELER Haszprunar's “Clado-Evolutionary” Classification of the Gastropoda—A Critique D. J. CRISP, J. G. WIEGHELL & С. A. RICHARDSON Lx Tidal Microgrowth Bands in Siphonaria gigas (Gastropoda, Pulmonata) From the Coast of Costa Rica ROBERT T. DILLON, JR. Karyotypic Evolution in Pleurocerid Snails. I. Genomic DNA Estimated by Flow О о а ee Sod Sates Dr A OSMAR DOMANESCHI & SONIA С. В. С. LOPES Calyptogena (Calyptogena) birmani, À New Species of Vesicomyidae (Mollusca- BivalvialrBromyBrazil aa Sn ee AR K. C. EMBERTON, G. S. KUNCIO, G. M. DAVIS, S. MICHAEL PHILLIPS, К. М. MONDEREWICZ & Y. H. GUO Comparison of Recent Classifications of Stylommatophoran Land-Snail Fami- lies, and Evaluation of Large-Ribosomal-RNA Sequencing for their Phylogenet- А NR ee er es KENNETH C. EMBERTON Retraction/Extension and Measurement Error in a Land Snail: Fffects of Sys- Leman Character crac erie aves ee co Aeneas cet o EE BE N ALISON HAYNES The Numbers of Freshwater Gastropods on Pacific Islands and the Theory of IS AMGEBIOGEOGLADIN Vc 26, scp о EUER JOSEPH HELLER оО МОЛИ обе naive Cotte erga ts BAe tal cee о PAULA M. MIKKELSEN & RUDIGER BIELER Biology and Comparative Anatomy of Divariscintilla yoyo and D. troglodytes, Two New Species of Galeommatidae (Bivalvia) from Stomatopod Burrows in Eastern RICO ea ch RS i oar A Pe agree re teary re бо eNOS ARE ke Ate W. F. PONDER, R. HERSHLER, & B. J. JENKINS An Endemic Radiation of Hydrobiid Snails from Artesian Springs in Northern South Australia: Tneir Taxonomy, Physiology, Distribution and Anatomy ...... A. STAIKOU & M. LAZARIDOU-DIMITRIADOU Feeding Experiments on and Energy Flux in a Natural Population of the Ed- ible Snail Helix lucorum L. (Gastropoda: Pulmonata: Stylommatophora) in KOC COM ae ec cate II SOTO IST A. STAIKOU & LAZARIDOU-DIMITRIADOU Aspects of the Live Cycle, Population Dynamics, Growth and Secondary Pro- duction of the Snail Monacha cartusiana (Muller, 1774) (Gastropoda Pulmonata) Е А ee dre a С Ree ee DONALD L. SWIDERSKI Analysis of Lymnaeacean Relationships Using Phylogenetic Systematics ..... KAZUSHIGE TANABE, JYUNZO TSUKAHARA & SHOZO HAYASAKA Comparative Morphology of Living Nautilus (Cephalopoda) From the Philippines, AE) PÉTER о RONALD B. TOLL Cross Sectional Morphology of the Gladius in the Family Ommastrephidae (Cephalopoda: Teuthoidea) and its Bearing on Intrafamilial Systematics ....... R. TRIEBSKORN Ultrastructural Changes in the Digestive Tract of Deroceras reticulatum (Muller) Induced by a Carbamate Molluscicide and by Metaldehyde .................. R. VITTURI & E. CATALANO | Spermatocyte Chromosomes and Nucleolus Organizer Regions (NORs) in Tri- colia speciosa (Mühlfeld, 1824) (Prosobranchia, Archaeogastropoda) ......... 205 371 229 197 363 327 197 237 259 175 24% 353 249 297 313 141 21 AWARDS FOR STUDY AT The Academy of Natural Sciences of Philadelphia The Academy of Natural Sciences of Philadelphia, through its Jessup and McHenry funds, makes available each year a limited number of awards to support students pursuing natural history studies at the Academy. These awards are pri- marily intended to assist predoctoral and immediate postdoctoral students. Awards usually include a stipend to help defray living expenses, and support for travel to and from the Academy. Application deadlines are 1 March and 1 October each year. Further information may be obtained by writing to: Chairman, Jessuo-McHenry Award Committee, Academy of Natural Sciences of Philadelphia, 19th and the Parkway, Philadelphia, Pennsylvania 19103, U.S.A. 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SUBSCRIPTION COSTS 25. For Vol. 32, personal subscriptions are U.S. $21.00 and institutional subscriptions are U.S. $31.00. Address inquiries to the Subscription Office. VOL. 31, NO. 2 MALACOLOGIA - CONTENTS D. J. CRISP, J. G. WIEGHELL & C. A. RICHARDSON Tidal Microgrowth Bands in Siphonaria gigas (Gastropoda, Pulmonata) From the Coast oMGOStA Ribas RR N N RE И ALISON HAYNES The Numbers of Freshwater Gastropods on Pacific Islands and the Theory of Island Biogeography DONALD L. SWIDERSKI Analysis of Lymnaeacean Relationships Using Phylogenetic Systematics JOSEPH HELLER Longevily in, Moises sca est poy wip e tetas load to ee ee KAZUSHIGE TANABE, JYUNZO TSUKAHARA & SHOZO HAYASAKA ‘aa Comparative Morphology of Living Nautilus (Cephalopoda) From the Philippines, Fiji and Palau : RONALD B. TOLL Cross Sectional Morphology of the Gladius in the Family Ommastrephidae (Cephalopoda: Teuthoidea) and its Bearing on Intrafamilial Systematics ....... K. C. EMBERTON, G. S. KUNCIO, G. M. DAVIS, S. MICHAEL PHILLIPS, K. M. MONDEREWICZ & Y. H. GUO yy Comparison of Recent Classifications of Stylommatophoran Land-Snail Fami- | lies, and Evaluation of Large-Ribosomal-RNA Sequencing for their Phylogenet- = ics dl IN OO AO 6) 6) ee) v) os) RE Te CORO SAA Ws) em) stalls eet ae A. STAIKOU & LAZARIDOU-DIMITRIADOU Aspects of the Live Cycle, Population Dynamics, Growth and Secondary Pro- = duction of the Snail Monacha cartusiana (Müller, 1774) (Gastropoda Pulmonata) = EIA AS NE ASS N Ee И ORNE 135% OSMAR DOMANESCHI & SÓNIA G. B. C. 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