Myers, Charles W.Schargel, Walter E.2006-09-182006-09-182006http://hdl.handle.net/2246/581013 p. : ill., map ; 26 cm.Includes bibliographical references (p. 13).Two new Andean snakes exhibit extreme morphology in a genus of South American dipsadine colubrids. One, Atractus attenuatus, new species, is a slender, exceptionally attenuated snake 420 mm in total length (adult male holotype), with 17 scale rows, a high ventral + subcaudal count (226), and an extremely vague pattern of numerous, closely spaced, indistinct dark crossbars on a brown ground color. Atractus attenuatus comes from 1000 m elevation in the northern end of the Cordillera Central (Sabanalarga, Antioquia, Colombia). A geographic neighbor, Atractus sanguineus Prado, is of similar morphology but differs in having distinct, widely spaced crossbars on a red ground color. At another extreme, Atractus gigas, new species, is a very robust snake that exceeds a meter in length (adult female holotype 1040 mm in total length), with a hint of pale transverse dorsal bars on a brown ground color. It is the largest known Atractus, differing in color pattern and details of scutellation from the several other congeners that attain lengths > 700 mm. The only known specimen has an azygous frontonasal scale that is atypical of colubrids (but is not an obvious aberrancy). Atractus gigas comes from 1900 m elevation on the Pacific versant of the Andes (Bosque Protector Râio Guajalito, Pichincha, Ecuador.2988395 bytesapplication/pdfen-USQL1 .A436 no.3532 2006Atractus attenuatusAtractus gigasAtractusAtractus -- Morphology.Snakes -- Colombia -- Antioquia (Dept.)Snakes -- Ecuador -- Pichincha (Province)Snakes -- Andes RegionReptiles -- Colombia -- Antioquia (Dept.)Reptiles -- Ecuador -- Pichincha (Province)Reptiles -- Andes Regiontext