Chapa Flat-nosed Snake

description

Description. Body cylindrical, rather elongated, slenderly built, TL 390 – 899 mm; tail relatively long, TaL / TL 0.20 – 0.31, thin, tapering, without clear sexual dimorphism; head small, subtrapezoid-shaped, HL / HW 1.10 – 1.47, moderately distinct from the poorly defined neck, dorsally depressed; snout short, SL / SW 0.55 – 0.78; eye moderate or large, EW / SOL 1.00 – 1.79, EW / HL 0.13 – 0.19; pupil shape rather variable, vertically elliptic, round, or irregular, usually asymmetric; interorbital distance medium, IOD / HW 0.41 – 0.56; nostril crescentic, somewhat kidneyshaped, piercing upper middle of nasal, directed dorsolaterally. Dentition. Maxillary teeth 29 – 34, progressively increasing in size, last 2 – 3 strongly enlarged without diastema. Hemipenis. Hemipenis in everted condition short and subcylindrical, not forked, reaches subcaudal 5 – 6, spinose and calyculate throughout, spines more or less uniform in size; sulcus spermaticus simple, reaching tip of each organ. Body scalation. Dorsal scale rows 17: 17: 17; vertebral not enlarged, smooth anteriorly, weakly keeled from row 5 to row 13 at midbody, strongly keeled posteriorly; ventrals 159 – 177, precloacal not divided

Taxonomic re-evaluation of the monotypic genus Pararhabdophis Bourret, 1934 (Squamata: Colubridae: Natricinae) with discovery of its type species, P. chapaensis, from China

description

Pararhabdophis chapaensis Bourret, 1934. Bull. Gén. Instr. Publ. Hanoi 14 (7): 131 – 132, fig. 2. Type locality. “ Chapa, province de Laokay (Tonkin), à l’altitude moyenne de 1.600 m., Indochine française ” [= Sa Pa, NW Lao Cai Prov., ext. N Vietnam, 22 ° 21 ’ N, 103 ° 50 ’ E, elevation 1500 – 1600 m]. Holotype. MNHN 1938.0125 (formerly RLB M. 270), a 690 + mm male (Collected by R. L. Bourret, collected around 1930 – 1931).

Taxonomic re-evaluation of the monotypic genus Pararhabdophis Bourret, 1934 (Squamata: Colubridae: Natricinae) with discovery of its type species, P. chapaensis, from China

diagnosis

Diagnosis. The species can be diagnosed from other morphologically similar species by a combination of the following characteristics: (1) Body elongate and slender, TL 390 – 899 mm; (2) tail relatively long, TaL / TL 0.20 – 0.31; (3) head subtrapezoid, moderately distinct from neck; (4) maxillary teeth 29 – 34, last 2 – 3 strongly enlarged, without any diastema; (5) nostrils directed dorsolaterally; (6) prefrontal paired, seven upper head scales as typical for colubroids; (7) internasals truncated anteriorly, sutures between them not in contact with prefrontal sutures; (8) supralabials nine, 4 th, 5 th and 6 th entering orbit; (9) dorsal scale rows 17: 17: 17, weakly keeled anteriorly, strongly keeled posteriorly; (10) ventrals 15 9 – 177; (11) subcaudals 83 – 114; (12) hemipenis reaching subcaudals 5 – 6, spinose throughout, not forked; (13) head brownish black, with irregular and complex golden stripes and spots, (14) anterior parts of supralabials 1 – 8 with a thicker upright or oblique stripe; (15) dorsal scales of row 5 and row 12 with pale orange blotches anteriorly and longitudinal rodlike pattern, forming two light discontinuous or continuous dorsolateral stripes along each

Taxonomic re-evaluation of the monotypic genus Pararhabdophis Bourret, 1934 (Squamata: Colubridae: Natricinae) with discovery of its type species, P. chapaensis, from China

distribution

Distribution. H. chapaensis is currently known from ten localities (Fig. 1), including northern Vietnam (Lao Cai Province, Sa Pa [type locality]; Lao Cai Province, Bat Xat, Y Ty; Cao Bang Province [David et al. 2015 b]; Yen Bai Province, Mu Cang Chai Species and Habitat Conservation Area, Che Tao Commune, Che Tao Village [Le et al. 2018]; Son La Province, Copia Nature Reserve, Co Ma and Long He [Pham et al. 2013]; Son La Province, Sop Cop Nature Reserve, Huoi Mot [Pham et al. 2013]), Laos (Houaphan Province, Viengthong District, Phou Louey National Protected Area, near Tad Loi Waterfall [David et al. 2015 b]; Houaphan Province, Viengthong District, near Viengthong [David et al. 2015 b]; Louangphabang Province, Hoay Tala 1, branch of the Nam Madao [David et al. 2015 b]), and southwestern China (Yunnan Province, Honghe Prefecture, Pingbian County, Daweishan Nature Reserve). Natural history. H. chapaensis inhabits water bodies in tropical / subtropical forests between elevations of 1,050 m and 2,046 m. The species is nocturnal, thus active and foraging at night. In southern Yunnan Province, a male specimen was observed actively preying upon tadpoles of treefrogs (Rhacophorus duboisi)

Taxonomic re-evaluation of the monotypic genus Pararhabdophis Bourret, 1934 (Squamata: Colubridae: Natricinae) with discovery of its type species, P. chapaensis, from China