Achalinus yangdatongi Hou & Wang & Guo & Chen & Yuan & Che 2021, sp. nov.
Creators: name: Hou, Shao-Bing
name: Wang, Kai
name: Guo, Peng
name: Chen, Jin-Min
name: Yuan, Zhi-Yong
name: Che, Jing
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Xenodermatidae
Achalinus
Achalinus yangdatongi

description: Achalinus yangdatongi sp. nov.
(Figs. 6 and 7)
Holotype. KIZ 034327, adult male, collected by Kai Xu on 15 April 2018 from Xiaoqiaogou (23.361°N, 104.686°E; 1609 m a.s.l.), Xichou County, Wenshan, Yunnan Province, China.
Diagnosis. Achalinus yangdatongi sp. nov. can be distinguished from recognized species of Achalinus by a combination of the following characters: (1) TaL/ToL 26.2% in the male; (2) suture between internasals distinctly longer than that between prefrontals; (3) internasal present; (4) loreal present; (5) supralabials 6; (6) temporals 2+2+3, anterior two temporals in contact with eye; (7) infralabials 6; (8) first pair of infralabials in contact with each other behind mental; (9) dorsal body scales in 23–23–19 rows; (10) scales behind head irregular in shape, smooth; (11) ventrals 161; (12) subcaudals 82, unpaired; (13) precloacal scale entire; (14) maxillary teeth 19; and (15) body surface black above and beneath, iridescent.
Description of holotype. Total length 397 mm (SVL 293 mm, TaL 104 mm); tail long, TaL/ToL 26.2%; body slender, cylindrical; head slightly distinct from neck, HL 11.6 mm; eye small, pupil vertically subelliptic. Rostral small, triangular, slightly visible from above; suture between internasals (1.9 mm) longer than that between prefrontals (1.3 mm); nostril in anterior part of nasal; frontal pentagonal, slightly broader than long, pointed backwards, much shorter than parietals; single pair of parietals; loreal rectangle, wider (LeL: 1.4 mm) than the height (HiL: 0.8 mm); single supraocular, in contact with loreal, prefrontals, frontal, parietals and superior anterior temporals; temporals 2+2+4, two anterior temporals all pentagonal and in contact with eye, superioanterior temporals in contact with parietal, inferioanterior temporal in contact with fourth and fifth supralabials; middle temporals elongated, inferior middle temporal in contact with sixth supralabials; four posterior temporals, superioposterior temporals biggest, inferioposterior temporal smallest; supralabials 6, first smallest, fourth and fifth entering orbit, sixth longest; mental in arc shape, separated from anterior chin shields; infralabials 6, first pair of infralabials in contact with each other behind mental; two pairs of chin shields, anterior one semicircle-shape, posterior pair in unequilateral quadrilateral shape; first three infralabials in contact with anterior chin shields; third and fourth infralabials in contact with posterior chin shields.
All scales with metallic luster, weakly iridescent; scales behind head irregular in shape, smooth without keeled; dorsal scale rows 23–23–19, scales lanceolate and strongly keeled; ventrals 161; subcaudals 82, unpaired; precloacal entire.
Coloration: In preservative, the dorsal surface of the body is black, the anterior portion of the coloration of underside of head is dark brown, and the posterior portion and throat is light brown. The color becomes darken gradually from the throat posteriorly until it becomes black, except the free margin of each ventral scale, which is grayish white.
Comparisons. A. yangdatongi sp. nov. is most similar to A. ater, in which both species have a suture between internasals distinctly longer than that between prefrontals, equal number of supralabials and infralabials (both 6), anterior temporals in contact with eyes, first pair of infralabials in contact with each other behind the mental, dorsal scales in 23–23–19 rows, as well as by the presence of internasal and loreal scales. However, the new species can be diagnosed from A. ater by having more subcaudals (SC 82 vs. 47–70), a comparatively longer tail (TaL/ToL 26.2% vs. 19.0%–22.0%), and different coloration of ventral head (the anterior portion dark brown, posterior portion and throat light brown vs. uniformly yellowish-white).
Achalinus yangdatongi sp. nov. differs from A. juliani by having fewer ventrals (161 vs. 173–179), fewer DSRH (23 vs. 25), and a distinct coloration (black on both dorsal and ventral surfaces vs. greyish brown dorsally, greyish cream ventrally).
Achalinus yangdatongi sp. nov. differs from A. tranganensis by having fewer ventrals (161 vs. 171), by having dorsal scale rows 23–23–19, smooth without keeled (vs. dorsal scales in 25–23–23 rows, keeled), by having temporals 2+2+4 (vs. 2+3).
Achalinus yangdatongi sp. nov. differs from A. emilyae and A. rufescens by having more infralabials (6 vs. 5 in both A. emilyae and A. rufescens), distinct body coloration (black on dorsal body and belly vs. dorsum iridescent pale yellowish brown in A. emilyae, and uniform pale reddish or reddish-brown dark grey dorsally in A. rufescens). Furthermore, the new species differ from A. rufescens by having more ventrals in males (161 vs. 131–137) (Table 4).
Achalinus yangdatongi sp. nov. differs from A. niger, A. werneri, A. yunkaiensis, and A. spinalis by having suture between the internasals distinctly longer than that between the prefrontals (vs. less than or subequal to), a comparatively longer tail (TaL/ToL 26.2% vs. 15.0%–18.0% in A. niger, 15.0%–25.0% in A. spinalis, and 18.0%–20.0% in A. yunkaiensis), fewer subcaudals in male (SC 82 vs. 89–98 in A. werneri); from A. formosanus, A. jinggangensis, A. pingbianensis, A. timi and A. zugorum by presence of loreal scale (vs. absence), fewer dorsal scale rows (23–23–19 vs. 25–25– 23 in A. timi, and 27–27– 25 in A. formosanus), and more subcaudals (SC 82 vs. 51–64 in A. jinggangensis, 56 in A. pingbianensis and 70 in A. zugorum); from A. meiguensis and A. panzhihuaensis sp. nov. by presence of internasal (vs. absent), absence of postocular (vs. present), as well as by having different state of nasal scales (separated vs. in contact each other behind the rostral), mental separated from anterior chin shields (vs. in contact), and first pair of infralabials in contact with each other (vs. separated); and from A. hainanus by having different temporal formula (2–2–3 vs. 1–2–3), more subcaudals (SC 82 vs. 67–69), and more infralabials (6 vs. 5).
Natural history and distribution. The holotype was found on a paved road near a reservoir on a drizzly night. The nearby habitat is characterized by secondary forests and abandoned farmlands (Fig. 7). At the type locality, this species is sympatric with Trimerodytes percarinatus (Boulenger, 1899), Protobothrops mucrosquamatus (Cantor, 1839), and Pareas sp. With the holotype and the genetically identified snake sheds, A. yangdatongi sp. nov. is only known from its type locality at Xiaoqiaogou, Xichou county, Wenshan Prefecture, Yunnan Province, China (Fig. 1).
Etymology. The species name, yangdatongi, is a patronym honoring the Chinese herpetologist, Dr. Da-Tong Yang. We name the new species after Dr. Yang in recognition of his great contributions to the herpetological research in Southwestern China, particularly in Yunnan Province where the new species is found. We suggest “Yang’s Odd-scaled Snake” as its common English name, and “ 杨氏ñffi ” (Pinyin: Yang Shi Ji She) as its Chinese common name.
description: Published as part of Hou, Shao-Bing, Wang, Kai, Guo, Peng, Chen, Jin-Min, Yuan, Zhi-Yong & Che, Jing, 2021, Two new species and a new country record of the genus Achalinus (Reptilia Squamata: Xenodermidae) from China, pp. 528-546 in Zootaxa 4950 (3) on pages 538-540, DOI: 10.11646/zootaxa.4950.3.6, http://zenodo.org/record/4650074