Sinonatrix yapingi, Guo & Zhu & Liu, 2019

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

Sinonatrix yapingi sp. nov.

Figs. 3–7

Holotype: YBU 15296, 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.

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. 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. 1 ). Since the first specimen was collected, no addition specimens have been found, although the type locality has been visited several times.

Figures

FIGURE 1. Map showing type locality of Sinonatrix yapingi sp. nov. (indicated in red triangle).

FIGURE 3. General view of holotype (YBU 15296) in life.

FIGURE 4. Dorsal (A) and ventral (B) views of holotype (YBU15296) in preservative.

FIGURE 5. Dorsal (A), ventral (B), and lateral (C) views of head of holotype in preservative.

FIGURE 6. Dorsal (A), ventral (B), and lateral (C) views of CT-scanned skull of Sinonatrix yapingi sp. nov.

FIGURE 7. Macrohabitat of Sinonatrix yapingi sp. nov. in type locality.