Gibara White-collared Racerlet

description

Description of holotype. See Fig. 4 for head scales. SVL 143.5 mm; Ta 90.5 mm (39 % TL), 234 mm TL. Head distinct from body; head length 8.6 mm (6 % SVL), head width 5.5 mm (64 % head length) at widest point, head height 3.5 mm at tallest point; interocular distance 3.7 mm (67 % head width); snout-eye distance 2.2 mm (25 % head length, HL); nostril-eye distance 1.5 mm; rostral subtriangular, 1.9 mm wide and 1.2 mm high, well visible in dorsal view; prefrontal divided, 1.6 mm long (17 % HL), 2.3 times longer than internasals; prefrontals not in contact with orbit, but instead contacting supraocular and upper half of the preocular; frontal subtriangular 2.5 mm long (29 % HL) and 2.2 mm wide; supraocular 1.8 mm long (21 % HL) and 0.9 mm wide, twice wider distally than proximally; parietals 3.4 mm long (39 % HL), 2.4 mm wide; nasal divided; nostril horizontally oval, its posterior border lying on the nasal suture, but most of the opening is on the prenasal scale; prenasal scale 0.7 mm (8 % HL); postnasal scale 0.6 mm (7 % HL); loreal single, quadrangular, 0.6 mm long (7 % HL) and 0.4 mm high; loreal contacting second supralabial; preocular single, two times higher than wide, entering o

A new semifossorial snake of the genus Arrhyton (Squamata: Dipsadidae) from eastern Cuba, with taxonomic comments on other species

diagnosis

Diagnosis. A species of the genus Arrhyton, related to A. redimitum, as shown in the molecular phylogeny of Fig. 3. It can be distinguished from other species of the genus by the combination of (1) a wide immaculate white neck band or collar; (2) faint body stripes on a gray to grayish-tan background; (3) a solidly black and sharply defined cephalic pattern (“ cap ”, sensu Schwartz 1965), surrounded by whitish gray; (4) a short and solidly pigmented dark stripe crossing the eye, interrupted posteriorly by the white neck band, (5) a mucronate rostral scale (see Discussion), (6) high number of ventral scales (145), and high number of subcaudal scales (132). Most Arrhyton species have basically three well-defined body stripes on a tan or brown background, but there is variation in this character and two additional paravertebral stripes may be present depending on the species, giving some taxa a quinquelineate pattern (Fig. 1 B – H). Arrhyton albicollum sp. nov. is closely related to A. redimitum. Juveniles of A. redimitum may have a pair of small occipital spots interrupted by the middorsal stripe or show narrow post-occipital indentations of the paler colored areas on either side of

A new semifossorial snake of the genus Arrhyton (Squamata: Dipsadidae) from eastern Cuba, with taxonomic comments on other species

distribution

Distribution. Arrhyton albicollum sp. nov. is only known from the type locality near the town of Gibara, ~ 36 km NNE from the city of Holguín in eastern Cuba (Fig. 5), but it probably occurs in suitable habitats between Bahía de Puerto Padre and Banes (Las Tunas and Holguín Provinces, respectively). Habitat. The type specimen was found under a pile of rocks at the entrance of Cueva de los Panaderos during the day (Fig. 6). Caves and sinkholes are common structures in the area. The locality has patches of secondary semideciduous forest on limestone rock; however, the native vegetation is being displaced by the invasive spiny-bush Dichrostachys cinerea and the whole area is threatened by human use of caves and the trash dumping. Associated herpetofauna and complementary description of habitat is in Díaz et al. (2014).

A new semifossorial snake of the genus Arrhyton (Squamata: Dipsadidae) from eastern Cuba, with taxonomic comments on other species

etymology

Etymology. The specific epithet is derived from the Latin words albus (white) and collum (neck), in reference to the conspicuous white neck band. Proposed English name. Gibara White-collared Racerlet

A new semifossorial snake of the genus Arrhyton (Squamata: Dipsadidae) from eastern Cuba, with taxonomic comments on other species