Sinonatrix yapingi

Guo, Peng, Zhu, Fei & Liu, Qin, 2019, A new member of the genus Sinonatrix (Serpentes: Colubridae) from western China, Zootaxa 4623 (3), pp. 535-544: 538-539

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Sinonatrix yapingi

sp. nov.

Sinonatrix yapingi  sp. nov.

Figs. 3–7View FIGURE 3View FIGURE 4View FIGURE 5View FIGURE 6View FIGURE 7

Holotype: YBU 15296View Materials, adult female, from Jingdong (24.53°N, 100.94°E), Yunnan Province, China, at an elevation of 1500 m a.s.l.; collected by F. Zhu and Z.Q. Zhang in August 2015.GoogleMaps 

Diagnosis: 1) Large body size (maximum total length more than 795 mm); 2) dorsal scales in 19-19-17 rows, moderately keeled except outer four; 3) prefrontal single; 4) ventral scales 149, subcaudals 55, paired; 5) cloaca divided; 6) body bands 30; 7) belly milk-white, without speckles or bands; 8) reduction of dorsal scale rows from 19 to 17 anterior to 90 th ventral scale; 9) reduction of caudodorsal scales rows from 8 to 6 anterior to 12 th subcaudal and from 6 to 4 anterior to 38 th subcaudal; 10) postorbital bones not in contact with frontals, with weak parietal ridge; end of supratemporal bones extending beyond braincase; maxillary teeth 25, last two not enlarged; dentary teeth 26. In addition, the genetic distances between the new species and each Sinonatrix  representative range from 14.6% to 15.0%.

Description of holotype: Adult female. Total length 795 mm, tail length 160 mm.

Body stout, cylindrical. Head elongated and narrow, about twice as long as wide; slightly flattened, snout blunt. Eye moderate. Rostral 1.5 times as broad as deep, just visible from above; nasal completely divided; nostril dorsolateral. Internasals much longer than broad, narrowed anteriorly, longer than prefrontal; single prefrontal, 1.6 times as broad as long, extending downward on both sides and touching loreals, preoculars, and nasals. Frontal shield-like, 1.5 times as long as broad, as long as distance from end of snout; parietal large, 1.7 times as long as broad. Supraoculars narrow and long, about twice as long as broad, slightly shorter than frontal. Loreals square, slightly longer than broad; one preocular; three or four postoculars, lowest one extending beyond eye. Six temporals, arranged 2+4 on left and 1/(1+1) +3 on right (anterior one long above 2 short + 2 posterior temporals). Nine supralabials, fifth entering eye, seventh largest; ten infralabials, first five in contact with anterior chin-shields. Dorsal scales in 19-19- 17 rows, all moderately keeled except outer four. Reduction of dorsal scale rows from 19 to 17 at 90 th ventral scale. Ventrals 149+1. Cloaca divided. Subcaudals 55, paired; reduction of dorsal scale rows on tail from 8 to 6 and from 6 to 4 at 12 th and 38 th subcaudals, respectively.

Nasals small and triangular, prefrontals broad, frontals about twice as long as broad. Postorbitals large, not touching frontals. Parietal ridge Y-shaped and strong; posterior end of supratemporal bones slender, extending beyond braincase. Quadrates broad. Maxillary teeth 25, last two not enlarged. Dentary teeth 26.

Dorsal surface gray-brown. Thirty black, irregular bands on both sides of vertebral line; bands arranged alternatively on both sides and contacting each other (single marking on vertebral line close to neck). V-shaped speckles occurring on both sides of body and close to ventral scales, connecting and constituting W-shaped markings from anterior to posterior. Dorsal surface of head uniformly dark without markings; belly and ventral surface of head uniformly yellowish white, infralabials gray dark outside. Ventral surface of tail gray-white with some blackish spots.

Ecological notes. The specimen was collected in a rice field close to an evergreen forest at 21:00 pm on 13 August 2015 ( Fig. 7View FIGURE 7). No data on its diet or reproductive behavior are currently available.

Etymology. The species is named after Dr. Yaping Zhang, a Chinese academician, in recognition of his great contribution to Chinese herpetological research. We suggest the following common names: “ ÎṪƬńĸ ” (Chinese) and Jingdong Water Snake (English).

Distribution. This species is currently known only from the type locality, Jingdong, Yunnan Province, China ( Fig. 1View FIGURE 1). Since the first specimen was collected, no addition specimens have been found, although the type locality has been visited several times.