Welborn’s Snail-eating Snake

description

Description of holotype. Adult male, SVL 542 mm, tail length 195 mm (incomplete); head length 16.4 mm (3.0 % SVL) from tip of snout to angle of jaw; head width 10.2 mm (62 % head length) taken at broadest point; snout-orbit distance 3.8 mm; head distinct from neck; snout short, blunt in dorsal outline and rounded in profile; rostral 2.4 mm wide, higher than broad; internasals 1.8 mm wide, broader than long; prefrontals 2.7 mm wide, longer than broad, not entering orbit; supraocular 3.8 mm long, longer than broad; frontal 4.1 mm long, hexagonal and with angled anterior border, in contact with prefrontals, supraoculars, and parietals; parietals 5.5 mm long, longer than broad; nasal divided, in contact with two supralabials, loreal, prefrontal, internasal, and rostral; loreal 2.1 mm long, longer than high, entering the orbit; eye diameter 3.4 mm; pupil semi-elliptical; one small preocular above loreal; two postoculars; temporals 2 + 2; seven supralabials with 4 th- 5 th contacting orbit; symphysial precluded from contacting chinshields by first pair of infralabials; nine infralabials with 1 st to 5 th contacting chinshields; three pairs of chinshields, first longer than wide; dorsal s

A consolidated phylogeny of snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Colombia, Ecuador, and Panama

description

Figs 4 f, 13, 14 a, 15 a Proposed standard English name: Welborn's Snail-eating Snake Proposed standard Spanish name: Culebra caracolera de Welborn

A consolidated phylogeny of snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Colombia, Ecuador, and Panama

diagnosis

Diagnosis. Dipsas welborni sp. nov. is placed in the genus Dipsas based on phylogenetic evidence (Fig. 1 b) and the absence of a labial that is noticeably higher than other labials. The species is diagnosed based on the following combination of characters: (1) 13 / 13 / 13 smooth dorsals with enlarged vertebral row (1.8 - 2.1 x as wide as adjacent rows); (2) loreal and a preocular in contact with orbit; (3) 7 - 8 supralabials with 4 th, 5 th, and occasionally 6 th, contacting orbit; (4) 8 - 9 infralabials with 1 st to 5 th or to 6 th in contact with chinshields, one pair of infralabials in contact behind symphysial; (5) 181 - 193 ventrals in males, 177 - 179 in females; (6) 107 - 116 divided subcaudals in males, 105 - 106 in females; (7) dorsal color consisting of 21 - 26 dark brown to blackish body blotches (8 - 13 dorsal scales long anteriorly and 2 - 5 dorsal scales long posteriorly) separated from each other by narrow (2 - 3 dorsal scales long) pale brown interspaces that become white towards the lower lateral side, ventral surfaces white with encroachment from the dorsal dark brown blotches and with smaller brownish marks in-between the blotches, dorsal aspect of head dark red

A consolidated phylogeny of snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Colombia, Ecuador, and Panama

distribution

Distribution. Dipsas welborni sp. nov. is known from 26 localities (listed in Suppl. material 2) along the Cordillera del Condor in southeastern Ecuador (provinces Morona Santiago and Zamora Chinchipe) and northern Peru (Amazonas department). The species occurs over an estimated area of 10,521 km 2 and has been recorded at elevations 853 - 1843 m above sea level (Fig. 16). One locality, Etseketai Entse, Amazonas department, Peru, is in the Rio Cenepa valley at ~ 245 m above sea level. Since this locality is much lower in elevation than other localities in the Cordillera del Condor, it is likely that the specimens collected there (USNM 316599 - 600) were actually found on the neighboring mountain ridges.

A consolidated phylogeny of snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Colombia, Ecuador, and Panama