Achalinus sheni Ma, Xu, Qi, Wang, Tang, Huang & Jiang 2023
Creators: name: Xu, Yu-Hao
name: Wang, Shuai
name: Ma, Shun
name: Burbrink, Frank T.
name: Peng, Li-Fang
name: Huang, Song
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Squamata
Xenodermidae
Achalinus
Achalinus sheni

description: Achalinus sheni Ma, Xu, Qi, Wang, Tang, Huang & Jiang, 2023
Figs 2, 3, 4, 5, 6 Common name: Shen’s Odd-scale Snake / Shěn Shì Jǐ Shé (沈氏脊蛇)
Specimens examined.
Three typical specimens: LFR 2023008 (adult female), LFR 2023009 (adult male), LFR 2023010 (adult female); and one albinistic specimen: LFR 2024015 (adult female), collected in July, 2023 from Yangshi Town, Lianyuan City, Loudi City, Hunan Province (27 ° 32 ' 07.08 " N, 111 ° 48 ' 31.68 " W, 370 m a. s. l.); coll. by Shu Li and Ziyuan Feng.
Description of the albinistic specimen.
Measurements and scalation. An adult female specimen (field number LFR 2024015) with SVL 354 mm (TL 416 mm and TAL 62 mm); tail relatively short, TAl / TL ratio 0.149; body slender and cylindrical; head slightly distinct from the neck; HW 5.8 mm; HL 10.8 mm; eye small; ED 1.1 mm; rostrum small, triangular, slightly visible from above; length of the suture between the internasals (LSBI 1.25 mm) subequal to the length of the suture between the prefrontals (LSBP 1.32 mm), LSBI / LSBP ratio 0.95; nostril in the anterior part of the nasal; prefrontals paired; frontal single, pentagonal, pointing to the rear, the width and length close; loreal one, subrectangular, LorL 1.6 mm, LorH 0.9 mm, LorH / LorL ratio 0.56; supraocular one, pentagonal, SPOL 1.9 mm; TEMP 7 / 8, arranged in three rows (2 + 1 + 4 in left and 2 + 2 + 4 in right), the anterior two contact the eye, ATUL 1.7 mm, SPOL / ATUL ratio 1.1; SL 6, the 4 th – 5 th contact the eye, the last one much elongated; two pairs of chin shields, the anterior pairs longer than the posterior pairs, followed by preventrals; one mental; IL 5, the first one contact with each other after the mental and before the 1 st chin-shields, 1 st – 3 rd touch the first pair of chin-shields.
Dorsal scales strongly keeled, lanceolate, 23 rows throughout the body, the outmost row smooth and significantly enlarged. VS 164; anal entire; SC 46, not paired.
Coloration. The comparison of color pattern between the albinistic specimen and the typical specimen are shown in Fig. 4. In life, dorsum (head, body, and tail) predominantly pastel yellow or paster orange owning to the lack of melanophoric pigments, and the iridescence on the body surface also disappears. Head scales in dorsal view same as dorsum, interstitial skin of dorsal and sutures of head scales milk star white. The iris was blood-red, with a reddish pupil. Supralabials, mental, and infralabials were pastel orange. The ventral ground color of body and tail were milk star white, darker on both sides than in the middle, and with free margins of ventral scales and subcaudals almost transparent with a slight hint of pastel orange (Figs 2, 3).
Expanded description of the females.
Measurements and scalation data of the newly collected specimens (1 male and 3 females) are presented in Table 3. Based on three newly collected female specimens (field number: LFR 2023008, LFR 2023010, LFR 2024015), an expanded description of the females is provided as below.
Measurements and scalation. Tail relatively short, TAL / TL ratio 0.149 –0.164; body slender and cylindrical, the maximal TL 416 mm with SVL 354 mm and TAL 62 mm; head relatively narrow, slightly distinct from the neck, HL 10.8–11.5 mm; HW 5.5–6.6 mm; rostrum small, triangular, slightly visible from above; eye small, pupil round, ED 1.1 mm; LSBI subequal to LSBP; nostril in the anterior part of the nasal; prefrontals 2, elongated; frontal 1, pentagonal, pointing to the rear, the width and length close; loreal one, subrectangular, LorL 1.6–1.7 mm, LorH 0.9–1.3 mm, LorH / LorL ratio 0.56–0.76; supraocular one, pentagonal, SPOL 1.6–1.9 mm; temporals long, arranged in three rows, TEMP 2 + 1 + 4, 2 + 2 + 3 or 2 + 2 + 4, the anterior two contact the eye, ATUL 1.7 mm, SPOL / ATUL ratio 0.94–1.12; SL 6, the 4 th – 5 th contact the eye, the last one much elongated; two pairs of chin shields, the anterior pairs longer than the posterior pairs, followed by preventrals; one mental; IL 5, the first one contact with each other after the mental and before the 1 st chin-shields, 1 st – 3 rd touch the first pair of chin-shields.
Dorsal scales 23-23 - 23, lanceolate and strongly keeled, the outmost row smooth and significantly enlarged. VS 172–174; CP entire; SC 46–49, unpaired.
Coloration in life. In life, the dorsum (head, body, and tail) is predominantly brownish black and slightly tinged with iridescence. Head scales in dorsal view are the same as the dorsum, and with the middle darker than the sides. Dorsum brownish black and the five innermost dorsal scale rows a little darker, forming an inconspicuous longitudinal vertebral line. Eyes pure black. Mental, infralabials, and chin shields light grayish brown. Ventral ground color of body and tail generally light grey or light taupe and darker on the sides. The free margins of ventral scales are greyish white (Fig. 4).
Coloration in preservation. In preservation, coloration still resembles the specimen in life, except that the coloration of dorsum further deepening, and the background color of the venter becomes light brownish grey (Fig. 5).
Variation.
The female specimens have a similar color pattern as male specimens, but in measurement and scalation features, there is variation by sex: females have a relatively large body size (TL 355–408 mm vs 149–371 mm in male); a significantly short tail, TAL / TL ratio 0.149 –0.164 (vs 0.183 –0.224 in male) (Fig. 6); more ventral scales (172–174 vs 161–170 in male); and fewer subcaudals (46–49 vs 55–61 in male) (Table 4).
Revision of diagnostic characters.
(1) dorsal scales strongly keeled, 23 rows throughout the body, the outmost row smooth and significantly enlarged; (2) tail relatively short, TAL / TL ratio 0.183 –0.224 in males, and 0.140 –0.164 in females; (3) the suture between internasals subequal to the suture between prefrontals; (4) loreal one, subrectangular, LorH / LorL 0.53–0.76; (5) ventrals 161–170 in males and 172–174 in females; (6) cloacal plate entire; (7) subcaudals 55–61 in males and 46–49 in females, not paired; (8) the length of supraocular almost equal to the length of upper anterior temporal; (9) vertebral line inconspicuous and subcaudal streak absent.
Natural history notes.
Achalinus sheni is currently known from Hunan Province, China: Lianyuan City, Nanyue District and Nanshan National Park, Shaoyang City (350–410 m a. s. l.). The known activity period of A. sheni is from March to October but activity peaks in early summer. The species usually prefers to hide under rocks, decaying wood, or fallen leaves, but it has sometimes been found on cement roads in the mountains after rain or on high-humidity nights. Through dissection, it was found that there were undigested earthworms in the intestine of specimen LFR 2023009. Therefore, we speculate that A. sheni feeds mainlyon worms in the wild.
description: Published as part of Xu, Yu-Hao, Wang, Shuai, Ma, Shun, Burbrink, Frank T., Peng, Li-Fang & Huang, Song, 2024, First report of albinism for Achalinus sheni (Serpentes, Xenodermidae), with extended diagnosis of the species, pp. 1-17 in ZooKeys 1209 on pages 1-17, DOI: 10.3897/zookeys.1209.128944