Tricolor Snailsucker

description

Description of holotype. (Fig. 1) INIRENA 2800. Juvenile male. SVL 210 mm; TL 67 mm; TotL 277 mm. HL 8.5 mm (from tip to posterior border of parietal) and 7.7 mm (from snout to posterior commissure of mouth); HW 5.0 mm, head distinct from body, approximately 2 times wider than neck. Snout short, blunt, SL 2.7 mm, contained 3.1 times in the HL, rounded in dorsal and lateral profile. Loreal region tall, canthus rostralis rounded. Rostral 1.4 times as broad as high (2.0 mm broad, 1.4 mm high); internasals broader than long (1.0 mm length, 1.6 mm width), rounded anteriorly, in lateral contact with anterior and posterior nasals; prefrontals relatively large, broader than long (1.7 mm length, 2.0 mm width), nearly rectangular, with posterior edge of scale pointed at supraocular and frontal suture, in median contact with each other and in lateral contact with postnasal, loreal, preocular (lower) and orbit; frontal 1.1 times longer than broad (2.8 mm long, 2.4 mm broad), pentagonal with angular tip posteriorly, in contact with prefrontals, supraoculars and parietals. One moderately large preocular on each side. Single supraocular moderate, in contact with prefrontal, frontal, parietal, and

Two new species of snail-eating snakes of the genus Tropidodipsas (Serpentes, Dipsadidae) from southern Mexico, with notes on related species

diagnosis

Diagnosis. Tropidodipsas tricolor sp. nov. is placed in the genus Tropidodipsas based on phylogenetic evidence (Fig. 6). It belongs to the Tropidodipsas fasciata group as defined by Kofron (1987) based on possessing a laterally compressed body, head distinctly wider than neck, protruding eyes of moderate to large diameter, vertebral and paravertebral scales not wider than other dorsal scales, 17 maxillary teeth, 18 dentary teeth, postmental scale absent. The species differs from all described species of Tropidodipsas based on the following combination of characters: (1) 15 / 15 / 15 rows of smooth dorsal scales with no enlarged vertebral row; (2) prefrontal broader than long, entering the orbit; (3) loreal square, equally long as high, not entering the orbit; (4) 183 ventral scales in males, 183 in females; (5) 78 - 79 divided subcaudals in males and 79 in females; (6) 19 - 22 reddish orange, light-edged bands on body, most with dark brown or black medial stippling, giving the snake a " tricolor " effect; 8 pale bands on tail; (7) ground color black or nearly so; (8) iris chocolate brown; (9) TL / SVL 0.31 in one male specimen, and 0.30 in one female specimen.

Two new species of snail-eating snakes of the genus Tropidodipsas (Serpentes, Dipsadidae) from southern Mexico, with notes on related species

distribution

Distribution, habitat and ecology. This species appears to be restricted to moderate elevations in Sierra Madre del Sur from central Guerrero to western Oaxaca (Fig. 10). Habitats include cloud forest, mesic pine-oak woodland, tropical evergreen forest, tropical semi-deciduous forest and combinations of those assemblages (Brown et al. 2007). Known from 700 - 2200 m a. s. l., though most localities are from 1700 - 2200 m a. s. l. with the exception of the Sierra de Atoyac where it has been found at 700 - 1000 m a. s. l. in mesic tropical evergreen forest (Fig. 3 A). Specimens were found at night on low or medium (1.5 - 3.0 m) vegetation, or dead on the road.

Two new species of snail-eating snakes of the genus Tropidodipsas (Serpentes, Dipsadidae) from southern Mexico, with notes on related species

etymology

Etymology. The specific epithet tricolor refers to the tricolor pattern of the black dorsal coloration interspersed by light dorsal bands of cream and reddish orange.

Two new species of snail-eating snakes of the genus Tropidodipsas (Serpentes, Dipsadidae) from southern Mexico, with notes on related species