Bev Ridgely’s Snail-Eater

description

Description of holotype. Adult male, SVL 602 mm, tail length 186 mm (31 % SVL); head length 20.9 mm (3 % SVL) from tip of snout to commissure of mouth; head width 12.4 mm (59 % head length) taken at broadest point; snout-orbit distance 21 mm; head distinct from neck; snout short, blunt in dorsal and lateral outline; rostral 3.5 mm wide, broader than high; internasals 1.9 mm wide, broader than long; prefrontals 4.4 mm wide, longer than broad, entering orbit; supraocular 4.4 mm long, longer than broad; frontal 4.1 mm long, pentagonal and rounded, in contact with prefrontals, supraoculars, and parietals; parietals 7.7 mm long, longer than broad; nasal weakly divided, in contact with first three supralabials, loreal, prefrontal, internasal, and rostral; loreal 3.7 mm long, longer than high, entering the orbit; eye diameter 3.9 mm; pupil semi-elliptical; no preocular; two postoculars; temporals 1 + 3 on the right side, 2 + 3 on the left side; eight supralabials with 5 th and 6 th contacting orbit on the right side, seven supralabials with 4 th and 5 th contacting orbit on the left side; symphysial separated from chinshields by the first pair of infralabials; nine infralabials, 1 - 7 con

Systematics of South American snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Ecuador and Peru

diagnosis

Diagnosis. Sibon bevridgelyi is placed in the genus Sibon based on phylogenetic evidence (Fig. 3) and on having the labial beneath primary temporal conspicuosly higher than other labials. The species differs from all described species of Sibon based on the following combination of characters: (1) 15 / 15 / 15 smooth dorsals with enlarged vertebral row (1.3 - 1.7 times as wide as adjacent rows); (2) seven supralabials with 4 th and 5 th contacting orbit or eight supralabials with 5 th and 6 th contacting orbit; (3) one pair of infralabials in contact behind symphysial; (4) postmental absent; (5) 175 - 193 ventrals in males, 193 in the single female; (6) 80 - 94 divided subcaudals in males, 98 in the single female; (7) dorsal and ventral ground color pale yellow with or without irregular black bands, and with a black stippled disruptive pattern of irregular rusty to reddish brown blotches that are separated from each other by light interspaces (Figs 6, 2 b, c); bands incomplete and stippling not prominent or absent on ventral surfaces; head heavily speckled or blotched with black or rusty pigment; eyes light slate blue to pale goldenrod with black speckles and reticulations; (8) 349

Systematics of South American snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Ecuador and Peru

distribution

Distribution. Northwestern Peru in the department of Piura, and southwestern Ecuador in the provinces of Azuay, Chimborazo, El Oro, Guayas, Los Rios and Manabi at elevations between 5 and 1206 m (Fig. 8).

Systematics of South American snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Ecuador and Peru

etymology

Etymology. The specific epithet honors the late Prof. Beverly S. Ridgely, life-long birder and conservationist, and father of Robert S. Ridgely, well known in Ecuadorian ornithological circles and co-author of The Birds of Ecuador. Though he never got to visit Buenaventura, from afar Bev continued to delight in the conservation successes of Fundacion Jocotoco, which now owns and manages one of the few protected areas where the Vulnerable Sibon bevridgelyi is known to occur.

Systematics of South American snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Ecuador and Peru