Number of Pages: 2Integrative BiologyGeological Science

Villa, Jaime D.

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Number of Pages: 2Integrative BiologyEarth and Planetary Science

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472.1 REPTILIA: SQUAMATA: SERPENTES: COLUBRIDAE HYDROMORPHUS, H. CONCOLOR, H. DUNNI Catalogue o f  American Amphibians and Reptiles. Via, Jaime D. 1990. Hydmmorphur, H. concobr, H. dunni. Hydromorphus Peters Central American Watersnakes Hydmmorphus Peters, 1859:142. Type species, Hydmmorphur con- colorPeters, by monotypy. Content. Two species, concolos and dunni, are recognized. Definition. Members of the genus Hydmmorphur are me- dium-sized colubrid snakes (males to 690, females to 797 mm TL) with broadly rounded heads barely distinct from the neck, and mod- erately sho i  tails (13-19'34 of TL). Eyes are small, with a round pupil. Nostrils are directed dorsally. Cephalic scales are typically colubrid . - except for having 1 or 3 internasals and 1 or 3 prefr&&als. Nasals are usually entire but may be partially or entirely divided below the nos- trils. A loreal is present and usually borders the orbit. A single, upper preocular is usually present (the lower preocular is usually fused to the loreal) but two or more may be found There are two pairs of chin shields with a mental groove variably developed or absent. Dorsal scales are smooth (except for supra-anal keels in one species), in 15- 17 rows at midbody, 13-1 5 near the vent. Anal plate and subcaudals are divided. Ventrals number 157-186, caudals 33-54. Dorsal color is dark gray to dark brown, somewhat paler on rows 1-2. The venter is yellowish or cream-colored with variable dark smudging along the edges and the center of the ventrals, more abundant on the posterior portion of the body. Hemipenes are short (to subcaudal ll), slightly bi-lobed, and unicapitate, with four large basal hoqks and large spines over the central part. The sulcus sperrnaticus is centrolineal and bifurcate. The capitulum is spinous proximally and calyculate distally. Descriptions. The most comprehensive descriptions of the genus are by Nelson (1966) and Savage and Domelly (1988). Illustrations. See species accounts. Distribution. The range extends from Guatemala to central Panami on the Caribbean versant and from central Costa Rica to central P a n a d  on the Pacific. Fossil Record. None. Pertinent Literature. Vila et al. (1988) summarized the literature to 1987. The genus was reviewed by Savage and Domefly (1988). Vila (1971) and Crother (1989) provided information on the hemipenes. Sol6rzano et al. (1989) described the karyotype. Etymology. The name Hydmmorphur is derived from the Greek hydor(water) and mophe (shape or form), in reference to the snake's aquatic habits. The gender is neuter. Key to Species. Prefrontal single; internasal single; dorsal scales in 21-17-15 to 17-15- 15 (usually 19-17-15) rows; no supra-anal keels; posterior chin shields slightly longer than the anterior pair .................... concolor Three prefrontals; two internasals; dorsal scales in 15-15-13 rows; supra-anal keels present; anterior chiin shields slightly longer than the posterior pair ................................................................... dunni Hydromorphus concolor Peters Central American Watersnake Hydmmotphur concolor Peters, 1859:277. Type locality: "Costa Rica." Holotype, Konigliche Zoijlogische Museum [no number Map. Distribution of Hydmmorphur concolor (circles; type-locality too imprecise to plot) and H. dunni (triangle) (modified from Savage and Donnelly, 1988). cited], an adult female, no date of collection (not examined by author). Hydmmorphur clarki Dunn, 1942:2. Type locality: "Agua ClaraVi- lage near Chagres River, Panami." Holotype, Academy of Nat- ural Sciences of Philadelphia 23910, a juvenile, sex unknown, consisting of a head and anterior body (examined by author). Content. No subspecies have been described. Ddnition. A species of Hydmmophus with a single prefrontal, no supra-anal keels, the anterior chin-shields longer than the posterior pair, and dorsal scale rows in 17-1 5-1 5 to 21-17-1 5 rows. Descriptions. The most complete descriptions of this spe- cies are in Taylor (1951,1954, Costa Rican specimens) and Wilson and Meyer (1982, 1985, Honduran specimens). Nelson (1966) and Savage and Donnelly (1988) described the species from throughout its range. V i a  (1971) and Crother (1989) described the hemipenes. Solonano et al. (1989) described eggs, a juvenile, and the karyotype. - Illustrations. Peters (1859) provided a l i e  drawing of the dorsal surface of the head of the holotype. Line drawings and photo- graphs of preserved specimens are in Nelson (1966). Savage and Domelly (1988) provided schematic line drawings of the cephalic scales. Via  (1971) illustrated the dorsal pattern of a Nicaraguan specimen. Vila (1 971) and Crother (1 989) illustrated the hemipenes. Sol6nano et al. (1989) illustrated the karyotype. Distribution. The species is found at low to moderate ele- vations from Guatemala through central Panami. It is typically active at night in and around small streams in lowland and premontane forests. Pertinent Literature. The species is included in faunal works or checklists for Honduras (Widson and Meyer, 1982, 1985), Nicaragua (Vdla, 1970, 1983), Costa Rica (Savage and Vila, 1986), Panarni (Smith, 1958), Middle America (Villa et al., 1988) and the Neotropics (Peters and Orejas-Miranda, 1970). Notes on biology are in Savage and Donnelly (1988) and Sol6rzano et al. (1989). Obst et al. (1988) statedthat thespecies' "principal diet is fishand frogs." The only item this snake is known to eat in its natural habitat is small freshwater crabs. Etymology. The name concolor is Latin for "uniformly col- ored," probably referring to the generally patternless dorsum. Figure. Hydromorphus concolor, adult from San Ignacio de Acosta, Costa Rica. Photographs courtesy of Norman J. Scott, Jr. Hydromorphus dunni Slwh Dunn's Watersnake samrnelten und an das Konigl. Zoologische Museum gesand- ten Schlangen. Monatsberichte der Koniglich. Pmssischen Akad. W i .  zu Berlin 1959:275-278. Peters, James A., and Braulio R. Orejas-Miranda 1970. Catalogue of Hydromorphus dunni Slevin, 1%2:474. Type locality, "Vicinity the Neotropical Squamata. Part 1, Snakes. U. S. Nat. Mus. Bull. North of Boquete, Chiriqui Province, Panama." Holotype, Cali- (297):l- 347. fornia Academy of Sciences 78939~ an couec- Savage, J. M., and Maureen A. Domelly. 1988. Variation and system- ted by Joseph R. Slevin July 30,1939 (not examined by author). atics in the colubrid snakes of the genus Hydromorphus. Am- - Content. No subspecies have been described. phibia-Reptilia 9:289-300. , and Jaime Villa R. 1986. Introduction to the herpetofauna of Costa R i a .  Soc. Stud. Amph. Rept., Contrib. ~e rpe to l .  (3):viii + Ddnition. A species of Hydromorphus with three prefron- 2% PP. tals, knob-like supra-anal keels, the posterior chin shields longer Slevin, Joseph R. 1942. Notes on a collection of reptiles from Boque- than the anterior pair, and dorsal scales in 15-15-13 rows. te, Panama, with the description of a new species of Hydromor- phuc. Proc. Cal. Acad. Sci. 23(32):473-480, pls. 39-42. Descriptions. The most complete description of this species Smith, Hobart M. 1958. Handlist of the snakes of Panama. Herpetol- is the original (Slevin, 1942). Savage and Domelly (1988) differen- tiated it from H. concolor. ogica 14(4):222-224. Sol6rzan0, Alejandro, J o g  M. GutiCrrez, and Luis Cerdas. 1989. Notes on-the natural history and karyotype of the colubrid mustratlOns. S1evin(1%2) provided a and white pho- snake, Hydmmorphus concolor Peters, from Costa Rica. J. Her- tograph of the dorsal portion of the head and neck, as well as the petol. 23(3):314-315. lateral poflion of the vent area of the hO1oty~;  he illusuated Taylor, Edward Harrison, 1951, A brief review of the snakes of Costa habitat. Savage and Donnelly (1988) provided a very schematic line Rica. Univ. Kansas Sci. Bull. 34(1):1-188. drawing of the dorsal surface of the head of the holotype illustrating 1954. Further studies on the snakes of Costa Rica. Univ. Kan- the arrangement of the anterior cephalic scales. sas Sci. Bull. 36(2):673-801. Distribution. The species is known only from the type- locality in "upland southwestern Panama in the premontane zone (ca 1250 rn)" (Savage and Domelly, 1988). Pertinent Literature. As for descriptions. Etymology. The name dunni honors Emmett Reid Dunn, who was "so intimately c o ~ e c t e d  with Central American herpetol- ogy." (Slevin, 1942). Literature Cited Crother, Brian 0. 1989. A redescription of the hemipenis of Hydm- morpbus wncolor(Colubridae) with comments on its tribal al- location. Copeia 1989(1):227-229. Dum, Emmett Reid. 1942. New or noteworthy snakes from Panama. Notulae Naturae 108:l-7 Nelson, Craig E. 1966. Systematics and distribution of snakes of the Central American genus Hydmmorphus (Colubridae). Texas Villa, Jaime. 1970. ~ i s i  tentativa de  vertebrados inferiores de Nica- ragua. Universidad Nacional Aut6nonoma de  Nicaragua, Ma- nagua. % p. . 1971. The snake Hydromopbus in Nicaragua, with a de- scription of its hemipenis. Carib. J. Sci. 10:119-121 [dated 19701. 1983. Nicaraguan Fihes, amphibians and reptiles: A check- list and bibliography. Universidad Centroamericana, Managua. 53 p. , Larry D. Wilson and Jerry D. Johnson. 1988. Middle Arneri- can herpetology. A bibliographic checklist. Univ. Missouri Press, Columbia. xxxvi+ 132 p. Wison, Larry D. and John R. Meyer. 1982. The Snakes of Honduras. Milwaukee Public Mus. Publ. Biol. Geol. (6):l-159. , and - . 1985. The Snakes of Honduras, 2nd. Ed. Mil- waukee Public Mus., x+ 150 pp. Jaime D. Villa, Directorate for Science and Engineering Education, National Science Foundation, Washington D.C. 20550. J. ~ c i .  ia:%5-371. Obst, Fritz Jurgen, Klaus Richter, and Udo Jacobs. 1988. The com- for this Lany Dayd pletely illustrated atlas of reptiles and amphibians for the ter- rarium. TFH Publications, Neptune, New Jersey. 831 p. Published 31 January 1990 and Copyright 01990 by the Society for Peters, W. 1859. ijber die von Hm. Dr. Hoffmann in Costa Rica ge- the Study of Amphibians and 

Hydromorphus, H. concolor, H. dunni

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Hydromorphus, H. concolor, H. dunni

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