A New Species of the Genus Rhabdophis Fitzinger, 1843 (Squamata: Colubridae) in Southwestern Sichuan, China

The genus Rhabdophis is a group of widely distributed snakes with more than 20 species. Recent field surveys uncovered a species in southwestern China, which has long been considered as R. pentasupralabialis. Combined molecular and morphological analyses revealed it as a new species Rhabdophis chiwen sp. nov. Based on 12 specimens, this new species is distinguished by the following characters: 1) dorsal body saddlebrown, dorsal scales typically with black margins forming spots and stripes, the margin of the outer row forming two faint dorsolateral black cross-bars alongside body; 2) ventral scales 151-159, the outer margin of ventral scales and several lateral rows of dorsal scales forming ventrolateral longitudinal brownish-red coloration, with faint black spots in the middle of ventral scales; 3) a black oblique stripe present below eyes, often with a black spot between the 2nd and 3rd supralabial and a black stripe on the 5th supralabiat 4) eyes dark khaki, pupils black; 5) infralahials usually 7, the first four in contact with anterior chin-shields; 6) temporal scales 1+1; 7) dorsal scales in 15 rows, feebly keeled except the outer 1-2 rows; 8) anal scale divided; subcaudals 45-59; 9) preocular 1 and postoculars 3 (occasionally 2},10) body medium-sized (snout-vent length: adult males 404-431 mm, adult females 409-476 nun); 11) tail moderate (tail length/total length in adult males 0205-0238. in adult females 0.172-0.193). With the discovery of this new species, the total number of species in genus Rhabdophis is 28 with 12th species known to occur in China.