Gibson's wolf snake

description

(Figs. 1 – 4) Lycodon fasciatus (nec Ophites fasciatus Anderson): Inger & Colwell 1977: 235.

A new species of the Lycodon fasciatus complex from the Khorat Plateau, eastern Thailand (Reptiles, Squamata, Colubridae)

description

Comparisons. It should be noted that, since no females of Lycodon gibsonae spec. nov. are known, only male characteristics were used in the comparisons. Lycodon gibsonae spec. nov. differs from most other species of the genus Lycodon, except those of the L. fasciatus - group as well as L. subcinctus, L. sidiki, L. dumerili, and L. butleri, by having its loreal contacting the eye. Lycodon gibsonae differs from L. subcinctus and L. sidiki by having a preocular (vs. absent) and from L. dumerili in having 8 infralabials (vs. 9) and by the lower number of subcaudals (91 or 92 vs. 111 – 120). Lycodon gibsonae spec. nov. belongs to the group of Lycodon fasciatus. It differs from L. fasciatus by (1) its much larger size (SVL of the largest male of L. gibsonae: 906 mm, SVL of the largest specimen among 26 males of L. fasciatus: 674 mm), (2) the number of ventrals (223 – 226 vs. 199 – 213 in 25 males of L. fasciatus), (3) the number of subcaudals (91 or 92 in 2 specimens of Lycodon gibsonae spec. nov. vs. 74 – 90 in 20 males of L. fasciatus), (4) the number of bands on the body (17 or 18 vs. 19 – 43 in Lycodon fasciatus sensu stricto), and (5) the pattern of the bands on the posterior part o

A new species of the Lycodon fasciatus complex from the Khorat Plateau, eastern Thailand (Reptiles, Squamata, Colubridae)

description

Description of the holotype. Body robust, slightly compressed laterally; neck forming a natural angle with the head; head subrectangular, elongate, flattened, well distinct from the neck; snout elongate, strongly flattened, oblique in profile, projecting over the lower jaw, 27.5 % of HL, or 2.2 times as long as diameter of eye; a weak canthus rostralis; upper maxilla strongly arched with an angulous apex, distinctly bent inwards anteriorly (one maxilla dissected); large oval nostril that opens laterally and nearly entirely divides the nasal at its center; eye average, its diameter barely greater than the distance between the edge of the lip and its lower margin, with a vertical pupil; tail comparatively long, thin and tapering. SVL 906 mm; TaL> 194 mm (mutilate). Dentition. Based on specimen FMNH 180144: total of 13 maxillary teeth, with the following formula: 4 small anterior teeth + 3 strongly enlarged teeth, thick + a wide gap, longer than the larger anterior teeth + 3 small teeth + a small gap + 3 strongly enlarged posterior teeth, also rather straight. Body scalation. Dorsal scales in 17 – 17 – 15 rows, smooth on 1 st – 4 th dorsal rows, moderately keeled on 5 th – 9 th rows a

A new species of the Lycodon fasciatus complex from the Khorat Plateau, eastern Thailand (Reptiles, Squamata, Colubridae)

diagnosis

Diagnosis. A species of the genus Lycodon, characterized by: (1) loreal entering orbit; (2) 17 – 17 – 15 dorsal scale rows; (3) upper 3 or 4 and vertebral dorsal scale rows keeled; (4) about 223 – 226 VEN in males; (5) about 91 – 92 SC in males; (6) relative tail length about 0.198 in males; (7) 17 – 18 cream, well-defined bands on a dark body; (8) first dorsal band starting at VEN 13 – 15; (9) width of the first band occupying 4, 5 or 6 vertebral scales; and (10) maximum SVL 906 mm in males. This species can be recognized by its ventral and subcaudal scale counts (both higher than in L. fasciatus), by the first band on the body (broader in terms of vertebral scales than in L. fasciatus), and on the number of bands on the body (lower than in L. fasciatus). Most other characters match those of L. fasciatus. Detailed comparisons with other species of the genus Lycodon appear below in the Discussion.

A new species of the Lycodon fasciatus complex from the Khorat Plateau, eastern Thailand (Reptiles, Squamata, Colubridae)