Achalinus damingensis, Yang & Xu & Wu & Gong & Huang & Xiang & Feng & Huang & Huang, 2023

Yang, Dian-Cheng, Xu, Yu-Hao, Wu, Jia-Xiang, Gong, Yan-An, Huang, Ru-Yi, Xiang, Jun, Feng, Zheng-Lian, Huang, Tian-Qi & Huang, Song, 2023, A new species of the genus Achalinus (Squamata: Xenodermidae) from Nanning, Guangxi, China, Zootaxa 5319 (3), pp. 389-402 : 395-400

Achalinus damingensis sp. nov. Yu-Hao Xu, Dian-Cheng Yang, Jia-Xiang Wu, Yan-An Gong, Ru-Yi Huang & Song Huang ( Figs. 3–5 )

Holotype. ANU20220009 (collection number: HSR22147), an adult male, was collected by Jiaxiang Wu, Jun Xiang & Zhenglian Feng on August 1, 2022 at 3: 40 p. m. It was found trapped in an abandoned pool with some water in it, in Daming Mountain (23°29′54.04″ N, 108°26′22.15″ E, 1272 m a. s. l.), Shanglin County, Nanning City , Guangxi Zhuang Autonomous Region, China.

Diagnosis. The new species of Achalinus can be distinguished from its congeners on the basis of the following combination of characters: (1) dorsum (head, body and tail) predominantly brownish-black, slightly tinged with iridescence; a bright yellow collar around the neck, extending forward to the ventral of the head; (2) DSR 23–23–23, moderately keeled; (3) TaL/ToL ratio 0.25 in the single male; (4) length of suture between internasal significantly longer than that between prefrontal, LSBI/LSBP ratio 1.34; (5) supralabials 6, the fourth and fifth in contact with the eye; (6) infralabials 6, the first three touching the first pair of chin shields; (7) temporals 7, arranged in three rows (2+2+3), the anterior pair elongated, in contact with the eye; (8) a single loreal; (9) ventrals 3+162; (10) subcaudals 74, unpaired; (11) cloacal plate entire; (12) two pairs of chin shields; (13) longitudinal vertebral line absent, with a dotted black streak in the middle of the subcaudals absent.

Description of holotype. The adult male specimen had the following characters: ToL 427 mm (SVL 322 mm and TaL 105 mm), tail complete, TaL/ToL ratio 0.25; body slender, cylindrical; head slightly distinct from the neck; HD 5.95 mm; HL 13.12 mm; eye small; ED 1.49 mm; rostrum small, triangular, slightly visible from above; length of suture between internasals significantly longer than that between prefrontals, LSBI 1.92 mm, LSBP 1.43 mm, LSBI/LSBP ratio 1.34; one supraocular pentagonal, in contact with loreal, prefrontal, frontal, parietal and the upper anterior temporal; prefrontals paired; frontal single, pentagonal, pointing to the rear, the width and length close; Loreal hexagonal, LorL 1.79 mm, LorH 1.17 mm, LorH/LorL ratio 0.65; TMP 7, arranged in three rows (2+2+3); the anterior pair elongated, in contact with the eye; the upper anterior temporal small, narrow pentagonal shape, in contact with the parietal, supraocular and eye; the lower anterior temporal large, hexagonal, in contact with fifth and sixth supralabials; SPL 6, the first one the smallest, fourth and fifth in contact with the eye, the sixth the longest; two pairs of chin shields, followed by preventrals; one mental; IFL 6, the first three touching the first pair of chin shields.

DSR 23–23–23, all dorsal scales fusiform, not overlapping, moderately keeled posterior to nape, and outermost dorsal scale row on both sides slightly keeled. Ventrals smooth, VS 3+162; SC 74, unpaired; CP entire.

Coloration of holotype in life. Dorsum (head, body and tail) predominantly brownish black, slightly tinged with iridescence, except for the neck with a bright yellow collar that extends forward to the ventral of the head. Head scales in dorsal view same as dorsum, interstitial skin of dorsal and sutures of head scales off-white. Supralabials mostly brownish black but infused with bright yellow along lower margins, eyes pure black. Mental and chin shields brownish-black, gular cream-yellow. Ventral ground color of body and tail same as dorsum, brownish-black, free margins of ventral scales and subcaudals grayish-white.

Coloration in preservative. The dorsal surface of the body is predominantly brownish black, slightly tinged with iridescence. The collar of the neck is grayish-white and paler. Chin shields are darkish-gray. Preventrals and the first three ventrals are grayish-white interspersed with brown. The rear ventrals are darkish-gray with a slight metallic luster. All scale margins are greyish-white.

Etymology. We named this species based on its type locality, Daming Mountain, Shanglin County, Nanning City, Guangxi Zhuang Autonomous Region, China. We suggest Dà Míng Shān Jĭ Shé (ĘDZψΰḆ) as Chinese common name and Daming odd-scaled snake as English common name.

Distribution and Habitat. At present, the new species is only known from the type locality, i.e., Daming Mountain, Shanglin County, Nanning City, Guangxi Zhuang Autonomous Region, China. We found the specimen trapped in an abandoned pool with some water in it, in the afternoon in the summer. We presume it fell into the trap on the preceding night. The surrounding habitat was well-preserved montane evergreen broadleaf forest at an elevation of 1272 m above sea level.

Comparisons. Achalinus damingensis sp. nov. can be differentiated from all other species of Achalinus by having the following characters: LSBI significantly longer than LSBP; loreal not being fused with the prefrontal; two pairs of chin shields; different infralabials, ventrals, subcaudals, and DSR counts; longitudinal vertebral line absent; a bright yellow collar around the neck. A detailed comparison between the new species and its congeners is summarized in Table 2 .

Achalinus damingensis sp. nov. differs from A. ater by having more subcaudals (74 vs. 47–70), a comparatively longer tail (TaL/ToL ratio 0.25 vs. 0.19–0.22), and a bright yellow collar around the neck.

Achalinus damingensis sp. nov. differs from A. yangdatongi by having different DSR counts (23–23–23 vs. 23–23–19), fewer subcaudals in males (74 vs. 82), and different coloration of dorsum in preservative ( Fig. 6 ).

Achalinus damingensis sp. nov. differs from A. ningshanensis by having more infralabials (6 vs. 5), two pairs of chin shields (vs. three pairs), LSBI significantly longer than LSBP (vs. suture between internasals is similar size when compared to the suture between prefrontals), and different coloration of dorsum in preservative ( Fig. 6 ).

Achalinus damingensis sp. nov. differs from A. juliani Ziegler, Nguyen, Pham, Nguyen, Pham, Van Schingen, Nguyen & Le, 2019 by having different DSR counts (23–23–23 vs. 25–23–23), fewer ventrals (162 vs. 173–179), fewer subcaudals (74 vs. 77–91), and a bright yellow collar around the neck.

Achalinus damingensis sp. nov. differs from A. pingbianensis Li, Yu, Wu, Liao, Tang, Liu & Guo, 2020 by having a separated loreal (vs. loreal fused with prefrontal), more subcaudals in males (74 vs. 56), LSBI significantly longer than LSBP (vs. length of suture between internasals subequal to that between prefrontals), two anterior temporals in contact with the eye (vs. only the upper anterior temporal in contact with the eye), fewer supralabials (6 vs. 7), and a bright yellow collar around the neck.

Achalinus damingensis sp. nov. differs from A. emilyae , A. rufescens , A. hainanus Huang, 1975 , A. spinalis , A. huangjietangi Huang, Peng & Huang, 2021 and A. dehuaensis Li, Wu, Xu, Zhu, Ren, Guo & Dong, 2021 by having more infralabials (6 vs. 5). Furthermore, the new species differs from A. emilyae by having more ventrals (162 vs. 157–161), and a bright yellow collar around the neck. It differs from A. rufescens by having two pairs of chin shields (vs. three pairs of chin shields) and two anterior temporals in contact with the eye (vs. only the upper anterior temporal in contact with the eye). It differs from A. spinalis and A. huangjietangi by the absence of longitudinal vertebral lines and the absence of a dotted black streak in the middle of the subcaudals. It differs from A. hainanus by having more anterior temporals (2 vs. 1). The new species differs from A. dehuaensis by having a comparatively shorter tail length in males (TaL/ToL ratio 0.25 vs. 0.26–0.29) and different body colors.

Achalinus damingensis 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. zugorum Miller, Davis, Luong, Do, Pham, Ziegler, Lee, De Queiroz, Reynolds & Nguyen, 2020 , and A. vanhoensis Ha, Ziegler, Sy, Le, Nguyen & Luu, 2022 by having a separated loreal (vs. the absence of a loreal). Furthermore, the new species differs from A. formosanus by having fewer midbody DSR (23 vs. 27). It differs from A. jinggangensis by having more subcaudals (74 vs. 51–64). It differs from A. timi by having different DSR counts (23–23–23 vs. 25–25–23) and differs from A. zugorum by having fewer infralabials (6 vs.7) and different DSR counts (23–23–23 vs. 25–23– 23), and it differs from A. vanhoensis by having different DSR counts (23–23–23 vs. 25–23–23).

Achalinus damingensis sp. nov. differs from A. meiguensis and A. panzhihuaensis Hou, Wang, Guo, Chen, Yuan & Che, 2021 by having two pairs of chin shields (vs. three pairs of chin shields) and having internasal (vs. internasal absence).

Achalinus damingensis sp. nov. differs from A. niger Maki, 1931 by having different DSR counts (23–23–23 vs. 25–25–23), LSBI significantly longer than LSBP (vs. suture between the internasals less than or subequal to that between the prefrontals), and a comparatively longer tail (TaL/ToL ratio 0.25 vs. 0.15–0.18).

Achalinus damingensis sp. nov. differs from A. tranganensis Luu, Ziegler, Ha, Lo, Hoang, Ngo, Le, Tran & Nguyen, 2020 by having different DSR counts (23–23–23 vs. 25–23–23), and temporals 2+2+3 (vs. 2+3).

Achalinus damingensis sp. nov. differs from A. werneri Van Denburgh, 1912 by having fewer ventrals (162 vs 174–191), fewer subcaudals in males (74 vs. 89–98), LSBI significantly longer than LSBP (vs. suture between internasals is similar size when compared to the suture between prefrontals), the absence of longitudinal vertebral lines, and the absence of a dotted black streak in the middle of the subcaudals.

Achalinus damingensis sp. nov. differs from A. yunkaiensis by having a relatively longer tail length (TaL/ToL 0.25 vs. 0.19–0.20), LSBI significantly longer than LSBP (vs. suture between internasals is similar size when compared to the suture between prefrontals), more subcaudals (74 vs. 49–56), and the absence of longitudinal vertebral lines.

Figures

FIGURE 3. General view of the holotype (ANU20220009) of Achalinus damingensis sp. nov. in life. Photo by Jun Xiang.

FIGURE 4. Dorsal (A) and ventral (B) views of the holotype (ANU20220009) of Achalinus damingensis sp. nov. in preservative. Photos by Dian-Cheng Yang.

FIGURE 5. Right (A), left (B), dorsal (C) and ventral (D) views of the head and lateral view of dorsal (E) of the holotype (ANU20220009) of Achalinus damingensis sp. nov. in preservative. Photos by Dian-Cheng Yang.

FIGURE 6. Comparisons of (1) dorsal overview, (2) ventral overview, (3) lateral head, (4) dorsal head, and (5) ventral head among A. damingensis sp. nov. (ANU20220009; holotype) (A), A. yangdatongi (KIZ 034327; holotype) (B), A. ningshanensis (ANU 20220002; paratype). Photos of the holotype of A. yangdatongi are obtained from Hou et al. (2021), remaining photos by Dian-Cheng Yang.