NUMBER 268 JULY 12, 1975 Q n .L52X NH TWO NEW SPECIES OF COLOSTETHUS (AMPHIBIA: ANURA: DENDROBATIDAE) FROM COLOMBIA By Philip A. Silverstone I# NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY r CONTRIBUTIONS IN SCENC6 Published by the NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY 900 Exposition Boulevard, Los Angeles, California 90007 SERIAL PUBLICATIONS OF THE NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY Prior to November 30, 1973, publications of the Natural History Museum have appeared under various formats — Leaflet Series, Museum Graphic, Science Series, Study Guides, Con- tributions in Science, Contributions in History, Science Bulletins, unnumbered catalogs of exhibitions, and other miscellaneous publications. The Museum now publishes the following serials at irregular intervals as CONTRIBUTIONS IN SCIENCE, HISTORY BULLETINS, SCIENCE BULLETINS, EDUCATION SERIES, HISTORY SERIES, and SCIENCE SE- RIES. The Contributions are short papers of octavo size. 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Editor All communications concerning CONTRIBUTIONS IN SCIENCE should be sent to the Editor, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007 NOV 23 2016 t/BRAR\^ TWO NEW SPECIES OF COLOSTETHUS (AMPHIBIA: ANURA: DENDROBATIDAE) FROM COLOMBIA' By Philip A. Silverstone^ Abstract: Two new species of dendrobatid frogs are described from Colombia: Colostethus abditaurantius from Bello, Departamento de Antioquia, and C. imbhcolus from the Alto del Buey, Departamento del Choco. C. ab- ditaurantius has extensively webbed toes, an orange calf-spot, and lacks a pale lateral stripe. C imbricolus has basally webbed toes, an orange calf-spot, and an incomplete pale lateral stripe. Introduction During field studies in Colombia in 1971, I collected specimens of two un- described species of dendrobatid frogs belonging to the genus Colostethus. The two species are described in this paper. Acknowledgments Field work was supported by the Natural History Museum of Los Angeles County Foundation. Collections were made under a scientific hunting license is- sued by INDERENA, for which I thank S. M. Franky V. and J. Hernandez C. I thank J. W. Wright, R. L. Bezy, and F. Truxal, Natural History Museum of Los Angeles County (LACM), Reverendo Hermano Niceforo Maria and Reverendo Hermano Daniel, Instituto de La Salle, Bogota, and C. J. Marinkelle, Univer- sidad de los Andes, Bogota, for their aid. The photographs are by the photographic staff of the Natural History Museum of Los Angeles County. Colostethus abditaurantius new species Figures 1 and 2 Holotype. — LACM 72000, collected at the Quebrada Altagracia, Bello, Departamento de Antioquia, Colombia, about 1450 m elevation, 28 August 1971, by P. A. Silverstone. Topoparatypes. — Two specimens, LACM 71999 and PAS 1003.71 (deposited with INDERENA), same data. Definition. — Snout-vent length (SVL) moderate (27-30 mm in known adult specimens); skin slightly granular on dorsum, smooth on venter; first finger ‘Review Committee for this Contribution Robert L. Bezy John R. Meyer Norman J. Scott John W. Wright ^Research Associate in Herpetology, Natural History Museum of Los Angeles County, Los Angeles, California 90007. 1 2 Contributions in Science No. 268 slightly shorter than second; third finger of adult male not swollen; toes three- fourths webbed; pale ventrolateral, lateral, dorsolateral, and vertebral stripes ab- sent; ventral spotting and marbling absent; throat of male not uniformly dark, not contrasting with color of belly; pale spot (orange in life, indistinguishable from white ground color in preservative) on proximoventral surface of calf. Diagnosis. — Colostethus abditaurantius differs from all described species of Colostethus in having a combination of two characteristics: a pale proximoventral calf-spot in life and extensively webbed toes. C. imbricolus and some specimens of C. subpunctatus also have a pale proximoventral calf-spot. C. abditaurantius dif- fers from C imbricolus in having extensively webbed toes, in lacking a pale lateral stripe, and in having an immaculate white venter (C. imbricolus has basally web- bed toes, an incomplete pale lateral stripe, and a dark venter with pale spots that Figure 1. Colostethus abditaurantius, dorsal aspect. Left: holotype, LACM 72000, female, 30.0 mm snout-vent length. Right: paratype, LACM 71999, male, 27.0 mm snout-vent length. 1975 COLOSTETHUS from Colombia 3 Figure 2. Colostethus abditaurantius, ventral aspect. Left: holotype, LACM 72000. Right: paratype, LACM 71999. are blue in life). C. abditaurantius differs from C. subpunctatus in having exten- sively webbed toes, and in lacking pale lateral and vertebral stripes (C. subpunc- tatus has basally webbed toes, has a complete pale lateral stripe, and often has a pale vertebral stripe). C. bocagei, C. chocoensis, C. collaris, C. dunni, C. fuliginosus, C. palmatus, C. riveroi, C. shrevei, and C. verged also have extensively webbed toes. C. abditaurantius differs from them in having a pale proximoventral calf-spot in life. It further differs from C collaris and C. riveroi in lacking a dark breast-band, from C. palmatus in having a smooth belly, and from C. collaris, C. dunni, C. palmatus, C. shrevei, and C. verged in lacking a pale lateral stripe. C. ab- ditaurantius differs from Phyllobates pictus (which also has a pale proximoventral calf-spot) in having teeth, in having toe webbing, in lacking a pale lateral stripe, and in lacking ventral marbling {P. pictus usually lacks teeth, lacks toe webbing, has a complete pale lateral stripe, and has dark or pale ventral marbling). 4 Contributions in Science No. 268 Description of holotype and LACM paratype. — The characteristics of the holotype are given first, followed in parentheses by the characteristics of the paratype, when they differ. The holotype is an adult female, 30.0 mm SVL (the paratype is an adult male, 27.0 mm SVL). The width of the body between the axil- lae is 35 percent (31 percent) of SVL. The length of the calf is 47 percent (50 percent) of SVL. The skin of the dorsum is slightly granular; the skin of the venter is smooth. A few ill-defined tubercles occur on the posterior portion of the upper sides of the body; a large, ill-defined tubercle occurs just back of the corner of the mouth. A longitudinal swelling extends from the posterior corner of the eye to the shoulder, concealing the posterodorsal portion of the tympanum. Maxillary and premaxillary teeth are present; vomerine Teeth are absent. The end of the snout is rounded in dorsal and lateral aspects. The canthus rostralis is rounded on the left side of the snout and angular on the right side. The loreal region is slightly con- cave. The interorbital distance is a little greater than the width of the upper eyelid. The diameter of the eye is almost twice the distance from the eye to the nostril and 2.3 times the diameter of the tympanum. The tympanum is round and somewhat indistinct; its posterodorsal portion is concealed. The finger disks are small relative to those of Dendrobates; they are about 1.5 times the width of the fingers. The first finger is slightly shorter than the second. The fingers are fringed but not webbed. A subarticular tubercle juts from the ventral surface of each phalangeal joint. An oblong inner and round outer tubercle protrude from the ventral sur- face of both the metacarpus and metatarsus. The tarsal fold is flaplike and slight- ly curved at its proximal extremity; it extends along the distal two-fifths of the dis- tance between the inner metatarsal tubercle and the heel fold. The tarsal tubercle is absent. The toes are fringed and about three-fourths webbed (Fig. 3). The web- bing formula (Savage and Heyer 1967) is: I r-2 II 1-2.5 III 2'-3 IV 3"-l V (I 1-2" II 1 +-2.5 III 2-3 IV 3-1.5 V). Color and color pattern: In life, the head and back were dark gray. Stripes were absent. White spots adorned the side of the head and body and the ventral surface of the thigh. There was an orange spot in the axilla, another in the groin, and another on the proximoventral surface of the calf. The throat, breast, and belly were white. In preservative, the head and back are immaculate dark brown (the head and back are pale brown, with the following dark brown areas: three spots on the dor- sal surface of the snout; an interorbital band, connecting posteriorly with a short median stripe; an undulating chevron on the back, with its apex posterior; the lateral borders of the mid-back; and extensive irregularly shaped areas on the posterior back). There are no pale ventrolateral, lateral, dorsolateral, or vertebral stripes. The upper lip is bordered with white, above which, to the level of the nostril, it is dark brown with a few small whitish spots (the upper lip is entirely dark brown, except for a whitish area on the tip of the snout); the side of the snout above the level of the nostril is immaculate dark brown, except for a short whitish stripe running from the eye almost to the nostril. The lower lip is white 1975 COLOSTETHVS from Colombia 5 with dark brown mottling, except at its posterior end, where it is brown with a few small white spots. The tympanum is white. The upper portion of the side of the body is dark brown, not contrasting strongly with the dark brown ground color of the dorsum (contrasting strongly with the light brown ground color of the dorsum); each side bears more than 25 small white spots. A white spot lies in the axilla. Four or five white spots decorate the side of the body on the border between the brown dorsal and white ventral ground colors; the most posterior of these spots lies in the groin. The dorsal surface of the forelimb is light brown, with a dark brown transverse band at the midpoint of the lower arm. The dorsal sur- face of the first and second fingers is much paler than that of the third and fourth fingers. The anterior surface of the upper arm is dark brown; that of the lower arm is mostly white. The ventral surface of the forelimb is white. The dorsal sur- face of the hind limb is light brown, with a dark brown transverse band on the thigh at a point one-third of the distance from the groin to the knee, another at the midpoint of the calf, and two more on the plantar surface of the tarsus (the Figure 3. Left foot, ventral aspect. Left; Colostethus imbricolus, holotype, LACM 71998. Right: Colostethus abditaurantius , paratype, LACM 71999. Line equals one millimeter. 6 Contributions in Science No. 268 transverse bands are darker and better defined, and the band on the thigh is slightly more distal). There is no light hook-shaped mark on the thigh. The dorsal surface of the first, second, and third toes is much paler than that of the fourth and fifth toes. The toe webbing is white. The proximal half of the anterior surface of the thigh bears a dark brown longitudinal stripe and three white spots (the spots are confluent and blend into the ventral ground color). The posterior sur- face of the thigh is dark brown with small oblong white spots. The median por- tion of the ventral surface of the thigh is white; this white area is surrounded by light brown (dark brown) borders, broken by extensive white mottling. The ventral surface of the calf is white. The throat, breast, and belly are immaculate white, except for a small amount of dark brown on the chin and lower lips. The surfaces of the muscles are pale flesh color with flecks of brown pigment; the flecks are sparse on the dorsum and absent on the venter. Type locality. — Bello is a town in the Cordillera Central, in the Depar- tamento de Antioquia, Colombia, 10 km north of Medellin. It has an elevation of 1450 m and a mean annual temperature of 22° C (data from the Oficina Depar- tamental de Estadistica de Antioquia). Etymology. — The name abditaurantius (from Latin: abditus = hidden, and aurantius = orange color) refers to the orange spots, which are concealed when the frog is in a sitting position. Colostethus imbricolus new species Figure 4 Holotype. — LACM 71998, collected at the upper Quebrada Mutata, Alto del Buey, Departamento del Choco, Colombia, about 200 to 300 m elevation, 22 August 1971, by Philip A. Silverstone. Topoparatypes. — Sixteen specimens, LACM 71983-97 and PAS 924.71 (deposited with INDERENA), same data. Definition. — Snout-vent length moderate (28.5 mm in only known adult specimen); skin smooth except for few tubercles on posterior back; first finger slightly shorter than second; toes basally webbed; pale ventrolateral and vertebral stripes absent; incomplete pale lateral stripe present; pale dorsolateral stripe present (but ill defined) in life, absent in preservative; venter dark with numerous small pale (blue in life) spots; throat of male not uniformly dark, but contrasting with color of belly; pale spot (orange in life, pink or white in preservative) on proximoventral surface of calf. Diagnosis. — Colostethus imbricolus differs from all described species of Colostethus in having a combination of three characteristics: a pale prox- imoventral calf-spot, basally webbed toes, and an incomplete pale lateral stripe. C. abditaurantius and some specimens of C. subpunctatus also have a pale prox- imoventral calf-spot. C. imbricolus differs from C. abditaurantius in having basal- ly webbed toes, an incomplete pale lateral stripe, and a dark venter with small pale spots that are blue in life (C. abditaurantius has extensively webbed toes, lacks a pale lateral stripe, and has an immaculate white venter). C. imbricolus dif- 1975 COLOSTETHUS from Colombia 7 fers from C. subpunctatus in having an incomplete pale lateral stripe and in lack- ing a pale vertebral stripe (C. subpunctatus has a complete pale lateral stripe and often has a pale vertebral stripe). C. imbricolus further differs from some or all of the other Chocoan species of Colostethus in having basally webbed toes (the toes are extensively webbed in C chocoensis and webless in C. nubicola, C. pratti, and C talamancae), in having an incomplete pale lateral stripe (the stripe is complete in C nubicola and absent in C chocoensis and C talamancae), in having a dark venter with small pale spots that are blue in life (the venter is not so patterned and lacks blue in C inguinalis, C. latinasus, C. nubicola, C. pratti, and C talamancae), and in lacking a contrasting dark throat and pale belly in males (males have this pattern in C inguinalis, some populations of C. nubicola, and C. talamancae). Colostethus imbricolus resembles Phyllobates pictus in having a pale spot on the proximoventral surface of the calf, but differs from P. pictus in the following respects: ( 1) the maxillary and premaxillary teeth are present (the teeth usually are absent in P. pictus)-, (2) the toes are basally webbed (the toes are webless in P. pictus)-, (3) the muscles are more sparsely pigmented than in P. pictus; (4) the first finger is shorter than the second (the first finger is equal to or longer than the second in P. pictus)-, (5) the pale lateral stripe is incomplete (the pale lateral stripe is complete in P. pictus)-, (6) the skin of the dorsum is smooth, except for a few posterior tubercles (the skin of the dorsum is granular in P. pictus). Description of holotype. — The holotype is an adult female, 28.5 mm SVL. The width of the body between the axillae is 23 percent of SVL. The length of the calf is 40 percent of SVL. The skin is smooth, except for a few low tubercles on the extreme posterior back and a few wrinkles on the posterior belly. Maxillary and premaxillary teeth are present; vomerine teeth are absent. The end of the Figure 4. Colostethus imbricolus, holotype, LACM 71998, female, 28.5 mm snout-vent length. Left: dorsal aspect; center; lateral aspect; right; ventral aspect. 8 Contributions in Science No. 268 snout is truncate in dorsal aspect and rounded in lateral aspect. The canthus rostralis is angular. The loreal region is slightly concave. The interorbital distance is a little greater than the width of the upper eyelid. The diameter of the eye is 1.4 times the distance from the eye to the nostril and almost three times the diameter of the tympanum. The tympanum is round; its posterodorsal portion is con- cealed. The finger disks are small relative to those of Dendrobates; they are about 1.5 times the width of the fingers. The first finger is slightly shorter than the second. The fingers lack fringes and webbing. A subarticular tubercle juts from the ventral surface of each phalangeal joint. An oblong inner and round outer tubercle protrude from the ventral surface of both the metacarpus and metatarsus. The tarsal fold is ridgelike and slightly curved. The tarsal tubercle is ill defined. The toes are fringed and basally webbed (Fig. 3). The webbing for- mula (Savage and Heyer 1967) is; I 2'-2.5 II 2'-3 III 3'-4 IV 4'''-3' V. Color and color pattern; In life, the head and back were dark brown with a pair of dull gold dorsolateral stripes, which were broad and ill defined on the back and narrow and well defined on the snout. The iris was black. The upper lip bore a gold stripe. The side of the body was black; it bore an incomplete gold lateral stripe. The dorsal surface of the hind limb was light brown with black transverse bands. There was a bright orange spot in the axilla, another on the proximoanterior surface of the thigh, and another on the proximoventral surface of the calf. The throat, breast, belly, and most of the ventral surface of the limbs were black with many small light blue spots. In preservative, the head and back are light brown with scattered dark brown mottling. There are no pale ventrolateral or vertebral stripes. The dorsolateral stripes have disappeared. An undulating white stripe extends from the arm inser- tion to a point beneath the anterior corner of the eye. Ventral to this, another white stripe begins at the posterior corner of the mouth and continues along the edge of the upper lip and around the tip of the snout. The side of the head and body is dark brown, except for white spots on the lower portion of the side of the body. A large white spot lies in the axilla. An incomplete undulating white lateral stripe extends from the groin to a point about three-fourths of the horizontal dis- tance from the groin to the axilla, and three-fourths of the vertical distance from the belly to the back. The anterior portion of the stripe is ill defined. On the right side, the stripe bears a small break midway between the groin and axilla. The dor- sal surface of the forelimb is tan. The anterior, posterior, and ventral surfaces of the forelimb are light brown with small white spots, except the anterior surface of the upper arm, which bears an elongate, dark brown, diagonal triangle, whose apex is distal. The dorsal surface of the hind limb is tan, with a dark brown transverse band at mid-thigh, another at mid-calf, and another at mid-tarsus, a dark brown proximal area on the thigh (surrounding an indistinct light brown hook-shaped mark), and irregular dark brown proximal areas on the calf. The anterior and posterior surfaces of the thigh are dark brown with a few small white 1975 COLOSTETHUS from Colombia 9 spots; a large white spot adorns the proximoanterior surface of the thigh. The ventral surface of the hind limb is light brown with many small white spots, ex- cept the proximal half of the calf, which bears a large, oblong white spot. The throat, breast, and belly are light brown, covered with numerous, small, close-set, elongate, sometimes curved white spots. The surfaces of the muscles are pale flesh color with flecks of brown pigment; the flecks are fairly numerous on the dorsum and sparse on the venter. Description of paratypes. — The 15 LACM paratypes, measured to the nearest one-half millimeter, vary from 16.0 to 20.5 mm SVL, with a mean of 18.4 mm (the mean for all 16 LACM specimens, including the 28.5 mm holotype, is 20.9 mm). All the paratypes are juveniles. They resemble the holotype. In some paratypes, the posterior belly is slightly granular. The end of the snout is vertical to rounded in lateral aspect. In some paratypes, the tarsal tubercle is well defined; in others, it is absent. Some specimens lack toe fringes, but this may be an artifact of preserva- tion. Color and color pattern; In life, the colors resembled those of the holotype, except that the ventral surface of the thigh was entirely light brown in some paratypes (it was black with blue spots, as in the holotype, in the others). In preservative, the dorsolateral stripes have disappeared. The pale lateral stripe extends only half-way along the side of the body; in a few specimens, the stripe is broken into three white spots. In the four smallest paratypes, the dark brown limb-bands contrast more strongly with the pale ground color than in the holotype; in these specimens, the dorsal surface of the thigh bears a white prox- imal hook-shaped mark (surrounded by dark brown) and three dark brown transverse bands. The most distal band meets a longitudinal dark brown stripe on the anterior surface of the thigh. The calf and the tarsus each have two dark brown transverse dorsal bands. In some of the larger paratypes (e.g., LACM 71995), the dark brown transverse bands cover most of the dorsal surface of the hind limb. In those specimens where the ventral surface of the thigh was uniform light brown in life, the light brown has become white in preservative. The white spot on the proximoventral surface of the calf covers from one-half to three- fourths of the length of the calf. In LACM 71992, the distal portion of the calf- spot narrows into an undulating stripe. The throat, breast, and belly are light gray or brown; they bear white markings, varying from tiny discrete white spots, to spots partially coalescing into marbling, to close-set marbling without discrete spots. Type locality. — The Alto del Buey is a mountain in the Serrania de Baudo, in the Departamento del Choco, Colombia. It lies in Holdridge’s (1967) lowland tropical rain forest zone, near the Pacific coast, on the divide between the Pacific drainage (the Rio del Valle to the west and the Rio Baudo to the south) and the Caribbean drainage (the Rio Atrato to the east and northeast). The American Geographic Society map NB-18 (scale 1:1,000,000) incorrectly shows the eleva- tion of the summit of the Alto del Buey as 1810 m; the actual elevation (shown on a summit marker and corroborated by my altimeter) is 1070 m. The type series of C. imbricolus was collected in the daytime, at the base of the Alto del Buey, on the 10 SMITHSONIAN LIBRARIES III 3 9088 01879 7225 Contributions in Science No. 268 bank of the upper Quebrada Mutata (a tributary of the Rio del Valle), at an elevation of about 200 to 300 m. The quebrada flows through virgin forest. Etymology. — The name imbricolus (from Latin: imber = rain, and coins = inhabiting) refers to the climate of the type locality. Generic allocation. — The discovery of C. imbricolus further narrows the dis- tinction between the genera Phyllobates and Colostethus (see Silverstone 1975). C. imbricolus is allocated to the genus Colostethus because: (1) the first finger is shorter than the second finger (this characteristic varies in Colostethus, but in all species of Phyllobates, the first finger is equal to or longer than the second finger); (2) the color of the muscles is pale, as in Colostethus (Savage 1968); (3) the dorsal and lateral coloration resembles that of many species of Colostethus. Resumen En esta obra se describen dos nuevas especies de Colostethus (Amphibia: Anura: Dendrobatidae) procedentes de Colombia: C. abditaurantius de Bello, Departamento de Antioquia, y C. imbricolus del Alto del Buey, Departamento del Choco. Ambas especies tienen una pinta anaranjada en la pantorrilla. C. ab- ditaurantius carece de una lista lateral y tiene la membrana interdigital bien desa- rrollada. C. imbricolus tiene una lista lateral parcial y \tiene la membrana inter- digital escasamente desarrollada. Literature Cited Holdridge, L. R. 1967. Life zone ecology. Revised ed. Tropical Science Center, San Jose, Costa Rica. 206 pp. Savage, J. M. 1968. The dendrobatid frogs of Central America. Copeia 1968:745-776. Savage, J. M., and W. R. Heyer. 1967. Variation and distribution in the tree-frog genus Phyllomedusa in Costa Rica, Central America. Beitr. Neotrop. Fauna 5:111-131. Silverstone, P. A. 1975. A revision of the poison-arrow frogs of the genus Dendrobates Wagler. Nat. Hist! Mus. Los Angeles Co., Sci. Bull. 21: 1-55. Accepted for publication May 5, 1975.