Opisthotropis haihaensis Ziegler, Pham, Nguyen, Nguyen, Wang, Wang, Stuart & Le, 2019

Wang, Jian, Lyu, Zhi-Tong, Zeng, Zhao-Chi, Lin, Chao-Yu, Yang, Jian-Huan, Nguyen, Truong Quang, Le, Minh D., Ziegler, Thomas & Wang, Ying-Yong, 2020, Re-examination of the Chinese record of Opisthotropis maculosa (Squamata, Natricidae), resulting in the first national record of O. haihaensis and description of a new species, ZooKeys 913, pp. 141-159 : 141

Opisthotropis haihaensis Ziegler, Pham, Nguyen, Nguyen, Wang, Wang, Stuart & Le, 2019 Figures 3 , 5A

Chresonymy.

Opisthotropis maculosa Stuart & Chuaynkern, 2007: Yang et al. (2011) (part); Nguyen et al. (2018).

Holotype.

IEBR A.2016.34 [Field No. QN 2016.91], adult female, from the forest near Tai Chi Village, Quang Son Commune, Hai Ha District, Quang Ninh Province, 950 m asl., Vietnam [exact locality and coordinates not provided owing to threat from collection for the pet trade ( Ziegler et al. 2019)], collected by Cuong The Pham and Tan Van Nguyen on 9 May 2016.

Specimens examined (N = 1).

SYS a000537, adult female, collected by Qing Du and Jian-Huan Yang on 10 July 2009 from Shiwandashan Nature Reserve [exact coordinates not provided owing to threat from collection for the pet trade], Shangsi County, Qinzhou City, Guangxi Zhuang Autonomous Region, 493 m a.s.l., P.R. China.

Etymology.

According to the original description, the specific name " haihaensis " refers to the type locality of this species, Haiha District (Quang Ninh Province) in Vietnam. As this species is currently reported in China, we suggest its Chinese name "Hai He Hou Leng She ( 海河后棱蛇)”, derived from its scientific name.

Variation.

Measurements, scalation and body proportions of the two specimens are listed in Table 3 . The specimen from China conforms to the holotype from Vietnam except for: (1) a shorter body size: snout-vent length 391.3 mm, tail length 108.9 mm (vs. SVL 396 mm, Tal 113 mm in the holotype); (2) a higher number of postoculars: PtO 2 (vs. PtO 1 in the holotype); (3) a lower number of maxillary teeth: MT 22 (vs. MT 24 in the holotype); (4) a lower number of ventrals: V 164+2 (vs. V 169+2 in the holotype); (5) a lower number of subcaudals: SC 75 (vs. SC 79 in the holotype); and (6) tail scales indistinctly keeled (vs. tail scales smooth in the holotype).

Revision of original diagnosis.

Opisthotropis haihaensis is characterized by the combination of the following characters: (1) TL 500.2-509 mm in adult females, (2) tail relatively long, TaL/TL 0.22, (3) internasal not in contact with loreal, prefrontal not touching supraocular, frontal touching preocular, (4) one preocular, one or two postocular(s), (5) temporals 1+1, (6) supralabials eight, fourth and fifth in contact with eye, (6) 22-24 maxillary teeth, (7) anterior pair of chin shields longer than posterior pair; (8) ventrals 164-169 (+ 2 preventrals), (9) subcaudals 75-79, (9) nasal cleft pointing to the first supralabial, (10) body scales in 15-15-15 rows, (11) body scales smooth, tail scales smooth or indistinctly keeled, (12) chin shields yellow with brownish black mottling, and (13) body and tail dorsum dark, each with a light yellow spot per scale.

Coloration in life (SYS r000537).

Eye black; scales on dorsal surface of head glossy black with scattered yellow flecking; chin shields yellow with brownish black mottling; body and tail glossy black with iridescence above, with single yellow spot on each scale, yellow spots becoming larger on sides of body; ventrals yellow with brownish black lateral margins and scattered brown flecks; subcaudals yellow with brownish black anterior and lateral margins in both specimens.

Coloration in preservation (SYS r000537).

Ground color of upper head and body surface dark brown, that of venter yellowish-beige. Dorsal scales each with light blotch in the center. Dorsal tail scales likewise with light central blotches. Dorsal head surface in part with indistinct light mottling. Anterior supralabials with large light mottling. Infralabials, chin shields and smaller throat scales anterior to ventrals yellowish-beige with dark brown mottling per scale. Belly with few, scattered dark flecks on sides. Outermost edges of light ventrals brown. Ground color of subcaudals brown with transversally enlarged light blotches at each scale end.

Distribution and habits.

Opisthotropis haihaensis is currently known from its type locality, the forest near Tai Chi Village (ca 950 m a.s.l.), Quang Ninh, northern Vietnam, and Shiwandashan Nature Reserve (ca 500 m a.s.l.), southwestern Guangxi, southern China. The straight-line distance between the two localities is approximately 150 kilometers, indicating that the distribution area of this species is the mountain region on the border between China and Vietnam.

The holotype was found at night in a small rocky stream at 21:30h. The surrounding habitat was secondary evergreen forest consisting of small hardwoods, bamboo, and shrubs. The air temperature was 24-29 °C and the relative humidity was 65-88%. The holotype revealed to be an adult female, as dissection showed up to 16.5 mm long eggs and the oviducts were folded, indicating that eggs had already been laid ( Ziegler et al. 2019). Besides, the other specimen, SYS r000537, was collected from a rocky stream (about 8 m wide and 0.3 m deep at the collecting site) running through well-preserved, dense deciduous forests. The collected individual was spotted swimming at night and swiftly hiding under stones when disturbed.

Figures

Figure 3. Morphological features of Opisthotropis haihaensis (SYS r 000537) from Shiwandashan Nature Reserve, Guangxi, China. A Habitus view B-D close-up of head scales. Photos by Jian Wang.

Figure 5. Comparisons of head scalation of Opisthotropis haihaensis and Opisthotropis hungtai sp. nov. Line illustration by Zhi-Tong Lyu.