Achalinus ningshanensis, Yang & Huang & Jiang & Burbrink & Yu & Zhang & Huang & Huang, 2022

Yang, Dian-Cheng, Huang, Ru-Yi, Jiang, Ke, Burbrink, Frank T., Yu, Yan-An Gong Jing, Zhang, Yi, Huang, Tian-Qi & Huang, Song, 2022, A new species of the genus Achalinus (Squamata: Xenodermidae) from Ningshan County, Shaanxi Province, China, Zootaxa 5190 (1), pp. 127-140 : 133-136

Achalinus ningshanensis sp. nov. D.C. Yang, R.Y Huang, K. JIANG, F.T. BURBRINK & S. Huang ( Figs. 3–5 )

Suggested English common name: Ningshan Odd-scaled Snake.

Suggested Chinese common name: Ťkḛffi (Bopomofo: Níng Shǎn Jǐ Shé).

Holotype. ANU20220001 (field number JK0917, Fig. 3 ), an adult female, collected in summer of 2008 from Xunyangba Town (33.5434 N, 108.5439 E, 1372 m a. s. l.), Ningshan County, Shaanxi Province, China by the team of Ke Jiang.

Paratypes. Six females, JK0918, JK0889, JK0890, JK0891, HSR19131, and HSR19132 (Voucher number: ANU20220002–7 ), all with the same collecting information as the holotype .

Diagnosis. Achalinus ningshanensis sp. nov. can be differentiated from all other members of the genus Achalinus by the following combination of morphological characters:(1) dorsum iridescent and uniformly dark brown in preservative, longitudinal vertebral line absent; (2) brown beneath; (3) dotted black streak in the middle of the subcaudals absent; (4) tail length relatively short, TaL/ToL 12–16% in females; (5) fewer subcaudals, 41–46, in females; (6) dorsal scales 23 rows throughout, strongly keeled, and the outer-most rows on both sides of the body also keeled and slightly enlarged; (7) one loreal; (8) internasal not fused to prefrontal; (9) suture between internasals is similar size when compared to the suture between prefrontals; (10) preocular and postocular absent; (11) 6 supralabials; (12) 5 infralabials, the first 3 (rarely 2) touching the first pair of chin shields; (13) 3 pairs of chin shields.

Description of the holotype. An adult female in excellent condition ( Figs. 3 & 4 ). Body slender and subcylindrical, total length 436 mm (SVL 374 mm and Tal 62 mm); tail relatively shorter, TaL/ToL 14%; head slightly distinct from neck dorsally covered with large head scales, head length 13.72 mm; head width 7.16 mm; eyes small with subround pupils.

Rostral small, subtriangular in frontal view, barely visible from above. Internasals paired, the suture between internasals (1.94 mm) subequal to that between prefrontals (1.63 mm); prefrontals paired, subrectangular. Frontal shield-shaped, nearly straight anteriorly, pointed backwards, slightly broader than it is long, and much shorter than the parietals. Parietals paired, the parietal suture longer than frontal. Nostril in the anterior part of the nasal. One loreal, rectangular, LorH: 0.97 mm, LorL: 1.90 mm (LorH/LorL: 0.51), extending from the nasal to the eye. One supraocular, in contact with loreal, prefrontals, frontal, parietals, and superior anterior temporals. No preocular or postocular. Temporals 2+3+4, two anterior temporals elongated, the upper one smaller in contact with parietal, the lower one in contact with fifth and sixth supralabials, both in contact with the eye; three elongated middle temporals; four elongated posterior temporals, the uppermost (super-temporal) significantly enlarged, the supertemporal split into two parts on the left, surrounding the parietal; the super-temporals from two sides contacting at the midline. Supralabials six, the first very small, 1–3 contacting the nasal, fourth and fifth contacting the orbit, fourth in narrow contact, fifth in broad contact, and sixth the longest and largest. One mental. Five infralabials, the first pair in contact blocking the mental from contacting an anterior pair of chin shields; first infralabial smallest, increasing in size until the fifth infralabial that is the longest. Three pairs of chin shields followed by ventrals. First three infralabials touching the first pair of chin shields on both sides.

Dorsal scale rows 23–23–23, dorsal scales fusiform, not overlapping, distinctly keeled posterior to nape, and outermost dorsal scale row on both sides slightly keeled and enlarged. Ventrals 167; cloacal plate entire; subcaudals 43, uniserial.

Coloration of holotype in preservative. Dorsum uniformly dark brown with metallic luster under light, the anterior portion of the head ash black, interstitial skin of dorsal dark brown. Ventral ground color brown, free margins of ventral scales grayish white.

Variation. Measurements, body proportions, and scale counts are listed in Table 1 . All paratypes are very similar to the holotype except in the following: paratypes JK0889, JK0891, and HSR19132 have two middle temporals ; paratypes JK0890 and HSR19131 have two middle temporals and three posterior temporals ; paratypes JK0890 have the first two infralabials touching the first pair of chin shields on both sides. The number of anterior temporals that contact the eyes is not a stable trait.

Comparisons. Achalinus ningshanensis sp. nov. can be differentiated from all other known species of snakes in the genus Achalinus by a combination of the following morphological characters: infralabials five, three pairs of chin shields, relatively shorter tail length (TaL/ToL 12–16% in females), longitudinal vertebral line absent, and missing a dotted black streak in the middle of the subcaudals.

Achalinus ningshanensis sp. nov. differs from all other species in Achalinus except A. spinalis Peters, 1869 , A. hainanus Huang, 1975 , A. emilyae Ziegler, Nguyen, Pham, Nguyen, Pham, Van Schingen, Nguyen & Le, 2019 , A. huangjietangi Huang, Peng, & Huang, 2021 , and A. dehuaensis Li, Wu, Xu, Zhu, Ren, Guo & Dong, 2021 by having fewer infralabials (five vs. six). Furthermore, it differs from A. spinalis and A. huangjietangi by having the following characters: absent longitudinal vertebral line, and missing a dotted black streak in the middle of the subcaudals; from A. hainanus by having two anterior temporals (vs. only one), three pairs of chin shields (vs. two pairs), fewer subcaudals in females (41–46 vs. 67–69); from A. emilyae by having fewer subcaudals in females (41–46 vs. 63), three pairs of chin shields (vs. two pairs), outermost dorsal scales rows keeled (vs. outmost rows smooth); from A. dehuaensis by having a relatively shorter tail length (TaL/ToL 12–16% vs. 21–22% in females), fewer subcaudals in females (41–46 vs. 63–65), uniformly dark brown above, light brown beneath (vs. greyish brown above, pale yellow beneath).

Achalinus ningshanensis sp. nov. differs from A. werneri Van denburgh, 1912 by having the following characters: absent longitudinal vertebral line, and missing a dotted black streak in the middle of the subcaudals.

Achalinus ningshanensis sp. nov. differs from A. yangdatongi by having fewer infralabials (5 vs. 6), different dorsal scale row counts (23–23–23 vs. 23–23–19) and having three pairs of chin shields (vs. two pairs).

Achalinus ningshanensis sp. nov. differs from A. ater by the suture between internasals subequal to that between prefrontals (vs. suture between internasals distinctly longer than between prefrontals) and having fewer subcaudals (41–46 vs. 56–63).

Achalinus ningshanensis sp. nov. differs from A. juliani by the suture between internasals subequal to that between prefrontals (vs. the suture between internasals distinctly longer than between prefrontals) and having a relatively shorter tail length (TaL/ToL 12–16% vs. 22–37%), fewer subcaudals (41–46 vs. 77–91), different dorsal scale row counts (23–23–23 vs. 25–23–23), and having three pairs of chin shields (vs. two pairs).

Achalinus ningshanensis sp. nov. differs from A. rufescens by having six supralabials, the fourth and fifth widely in contact with the eye (vs. five supralabials, third and fourth entering the eye) and being light brown beneath (vs. uniform yellowish beneath).

Achalinus ningshanensis sp. nov. differs from A. formosanus Boulenger, 1908 , A. jinggangensis ( Zong & Ma, 1983) , A. timi Ziegler, Nguyen, Pham, Nguyen, Pham, Van Schingen, Nguyen & Le, 2019 , A. pingbianensis Li, Yu, Wu, Liao, Tang, Liu & Guo, 2020 , A. zugorum Miller, Davis, Luong, Do, Pham, Ziegler, Lee, De Queiroz, Reynolds & Nguyen, 2020 , by having a separated loreal (vs. absence). Further it is different from A. formosanus by having fewer midbody dorsal scale rows (23 vs. 27), three pairs of chin shields (vs. two pairs), fewer subcaudals in females (41–46 vs. 61–70); from A. jinggangensis by having fewer infralabials (5 vs. 6), three pairs of chin shields (vs. two pairs), fewer subcaudals in females (41–46 vs. 51); from A. timi by different dorsal scale row counts (23–23–23 vs. 25–25–23), fewer infralabials (5 vs. 6), three pairs of chin shields (vs. two pairs), and the suture between internasals subequal to that between prefrontals (vs. the suture between internasals distinctly longer than between prefrontals); from A. pingbianensis by having fewer infralabials (5 vs. 6), fewer supralabials (6 vs. 7), 3 pairs of chin shields (vs. 2 pairs), and being uniformly dark brown above, light brown beneath (vs. uniform black above and beneath), and from A. zugorum by having fewer infralabials (5 vs. 6), 3 pairs of chin shields (vs. 2 pairs).

Achalinus ningshanensis sp. nov. differs from A. meiguensis Hu & Zhao, 1966 and A. panzhihuaensis by having divided internasals (vs. absent), absence of postocular (vs. presence), fewer infralabials (5 vs. 6), mental separated from anterior chin shields (vs. in contact), and the first pair of infralabials in contact (vs. separated). Furthermore, it differs from A. panzhihuaensis by different dorsal scale row counts (23–23–23 vs. 23–23–19).

Achalinus ningshanensis sp. nov. differs from A. niger Maki, 1931 by having fewer infralabials (five vs. six), different dorsal scale row counts (23–23–23 vs. 25–25–23), and fewer subcaudals in females (41–46 vs. 52–58).

Achalinus ningshanensis sp. nov. differs from A. tranganensis Luu, Ziegler, Ha, Lo, Hoang, Ngo, Le, Tran & Nguyen, 2020 by having fewer infralabials (five vs. six), three pairs of chin shields (vs. two pairs), a relatively shorter tail length (TaL/ToL 12–16% vs. 25%), and fewer subcaudals in females (41–46 vs. 73+).

Achalinus ningshanensis sp. nov. differs from A. yunkaiensis Wang, Li & Wang, 2019 by having fewer infralabials (five vs. six), three pairs of chin shields (vs. two pairs), and the outer-most dorsal scales rows keeled (vs. outmost rows smooth).

Etymology. The specific epithet refers to the location of type specimens, Ningshan County, Shaanxi Province, China. We suggest Níng Shǎn Jǐ Shé (Ťkḛffi) as Chinese common name, and Ningshan Odd-scaled Snake as English common name.

Distribution and habits. Achalinus ningshanensis sp. nov. is currently known only from the type locality Ningshan County, Shaanxi Province, China. All the specimens were found in farmland. The surrounding habitat was composed of secondary conifer/broad-leaved mixed forest. The new species is sympatric with A. cf. spinalis , A. cf. rufescens , Stichophanes ningshaanensis (Yuan, 1983) , Euprepiophis mandarinus (Cantor, 1842) , Elaphe taeniura (Cope, 1861) , E. carinata (Günther, 1864), E. xiphodonta Qi, Shi, Ma, Gao, Bu, Grismer, Li, Wang 2021 , Oreocryptophis porphyraceus (Cantor, 1839) , Cyclophiops major (Günther, 1858), Lycodon ruhstrati (Fischer, 1886) , L. liuchengchaoi Zhang, Jiang, Vogel and Rao, 2011 , Pseudoxenodon macrops (Blyth, 1855) , Rhabdophis nuchalis (Boulenger, 1891) , Zaocys dhumnades (Cantor, 1842) , Azemiops kharini Orlov, Ryabov and Nguyen, 2013 , Gloydius qinlingensis (Song and Chen, 1985), Protobothrops jerdonii (Günther, 1875)

Figures

FIGURE 3. Dorsal (A) and ventral (B) views of the preserved holotype of Achalinus ningshanensis (ANU 20220001).

FIGURE 4. Right (A), left (B), ventral (C) and dorsal (D) views of the head, lateral view of dorsal (E), and ventral views of the tail (F) of the holotype of Achalinus ningshanensis (ANU 20220001), after preservation.

FIGURE 5. General aspect of the paratype of Achalinus ningshanensis (JK0918) after preservation. Dorsal (A) and ventral (B) views; right (C), left (D), dorsal (E) and ventral (F) views of head.