Thursday, June 30, 2016

Trinidad Snail-eating Snake, Dipsas trinitatis (Family Dipsadidae)

Dipsas trinitatis Parker 1926: 206.
Dipsas variegata trinitatis — Peters 1960: 139.
Dipsas trinitatis — Harvey 2008.

Size: 638 mm SVL, 165 mm tail; tail 25–36% of the SVL. Identification: Slender, yellow, tan, and brown with 17–24 blotches on the dorsum; head significantly larger than the neck; the only Trinidad snake lacking a mental groove on the chin. Crown dark brown, sides of head tan, with dark brown pigment on seams of labials.  Similar species: Perhaps most easily confused with Sibon nebulata that is similar in body and head shape but is gray or brown and white and has a mental groove. Rostral barely visible from above; smooth scales in 15 rows with the vertebral row slightly enlarged, ventrals 168–189, subcaudals divided 81–92. Loreal single, one preocular, two postoculars, 7-9 upper labials, 9-12 lower labials, anal plate single 

Distribution: probably endemic to Trinidad but may also occur in the vicinity of Guarico, Venezuela. Habitat: A forest-edge snake that uses habitats disturbed by humans. Biology: Crepuscular, nocturnal; activity is sporadic. Diet: snails that lack an operculum; the snake uses a ratchet-like motion of its lower jaw to remove the snail from the shell.

Boos, H.E.A. 2001. The snakes of Trinidad and Tobago. Texas A&M University Press, 270 pp.
Harvey, Michael B. 2008. New and Poorly Known Dipsas (Serpentes: Colubridae) from Northern South America. Herpetologica 64 (4): 422-451.
Murphy, J.C. 1997. Amphibians and Reptiles of Trinidad and Tobago. Krieger Publishing, Malabar.
Murphy, J. C. and M. G. Rutherford.  2014. The first report of the snail-eating snake Dipsas variegata (Duméril, Bibron and Duméril) on Trinidad, its relationship to Dipsas trinitatis Parker (Squamata, Dipsadidae), and a discussion of microcephalic and macrocephalic ecomorphs in Dipsas. Herpetology Notes 7: 757-760.
Parker, H. W. 1926. A new snake from Trinidad. Ann. Mag. Nat. Hist. (9) 18: 205-207
Peters, J. A. 1960. The snakes of the subfamily Dipsadinae. Misc. Publ. Mus. Zool., Univ. Michigan (114): 224 pp.
Peters, J,A. Donoso-Barros, R. & Orejas-Miranda B. 1970. Catalogue of the Neotropical Squamata: Part I Snakes. Part II Lizards and Amphisbaenians. Bull. US Natl. Mus. 297: 347 pp.
Wallach, V. K. L. Williams, J. Boundy 2014. Snakes of the World: A Catalogue of Living and Extinct Species. Taylor and Francis, CRC Press, 1237 pp.

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