Achalinus hunanensis, Ma & Shi & Xiang & Shu & Jiang, 2023

Ma, Shun, Shi, Sheng-Chao, Xiang, Sun-Jun, Shu, Fu & Jiang, Jian-Ping, 2023, A new species of Achalinus Peters, 1869 (Squamata, Xenodermidae) from Hunan Province, China, ZooKeys 1166, pp. 315-331 : 315

Achalinus hunanensis sp. nov.

Figs 4 , 5

Chresonymy.

Achalinus ater : Shu et al. 2014; Shen et al. 2014; Gao et al. 2022.

Material examined.

Holotype. CIB 119039 (Collection No. 20130505001), subadult male (Fig. 4 ), collected in early May 2013, by Sheng-Chao Shi and Sun-Jun Xiang from Huangyan Village , Hecheng District, Huaihua City, Hunan Province, China (27°28′N, 110°02′E; ca. 880 m a.s.l.).

Paratype. CIB 119040, subadult male (Fig. 5 ), collected on 16 June 2022, by Sheng-Qiang Liu from Wazizhai , Ningxiang County, Changsha City, Hunan Province, China (28°00′N, 111°53′E; ca. 1020 m a.s.l.) .

Etymology.

This new species is named after its known distribution range, which is endemic to Hunan Province. The Chinese name is suggested as “湖南脊蛇” ( Hú Nán Jǐ Shé) and the English name "Hunan Odd-scale Snake" or "Hunan Burrowing Snake" is suggested.

Diagnosis.

(1) 23 rows of dorsal scales throughout the body, all dorsal scales strongly keeled, and the outmost one strongly keeled and enlarged; (2) tail relatively short, TaL/TL 0.221 ~ 0.225; (3) maxillary teeth 23; (4) the suture between internasals 2 × as long as that between prefrontals; (5) loreal one, subrectangular, LorH/LorL 0.62 ~ 0.70; (6) supralabials six, the 4th and 5th touch the eye; (7) the two anterior temporals in contact with eye; (8) ventrals 163-165, subcaudals 69-72, not paired.

Description of holotype.

A subadult male with a total length of 329 mm (SVL 255 mm and TaL 74 mm); tail relatively short, Tal/TL 0.225; body slender, cylindrical; head length (HL) 7.91 mm, head width 4.80 mm, HL/HW 1.65, slightly distinct from neck; eye small, ED 1.42/1.41 mm; maxillary teeth 23, small, equally sized and curved. Rostral small, triangular, only the upper tip visible from above. Length of the suture between the internasals (LSBI 1.78 mm) ~ 2 × as long as length of the suture between the prefrontals (LSBP 0.88 mm). Nostril in the anterior part of the nasal. Loreal one, subrectangular, loreal height (LorH) 1.03/1.04 mm, loreal length (LorL) 0.70/0.66 mm, LorH/LorL 0.62 ~ 0.70. Supraocular one. Frontal one, pentagonal, pointed backwards, much shorter than the parietals. Parietals paired and elongated. No preoculars and postoculars. Temporals 2+2+4, the anterior two contact the eye, the lower anterior temporal much larger, the upper medium temporal much larger, the upper posterior temporal much larger and separated from the other side one by two small scales which contact the parietals. Supralabials 6, 4th and 5th contact the eye, the last one much elongated. One mental. Two chin shields, similar length. Infralabials 5/6, the first one contact with each other after the mental and before the 1st chin shields, 1st-3rd/1st-4th touch the 1st chin shields.

Dorsal scales lanceolate and strongly keeled; 23 rows throughout the body; those of the outmost rows on both sides significantly enlarged and strongly keeled. Ventrals 163, with two preventrals; anal entire; subcaudals 69, not paired.

Coloration of holotype.

In life, dorsum dark, slightly metallic, vent black-brown, dark brown near the margin, grey in the margin. A yellowish brown patch on the head occipital. The head ventral anterior part dark brown and posterior part yellowish white ( Shu et al. 2014). In preservation, dorsum brown, vent anterior part grey and posterior part light brown. Ventral side of tail brown. The head ventral anterior part brown and posterior part grey.

Variations.

Main morphological characters were listed in Table 3 . The other sample are very similar to the holotype except that: (1) more ventrals: CIB 119040: 165; (2) more subcaudals: CIB 119040: 72; (3) vent coloration: CIB 119040: dark brown throughout the vent.

Distribution and habits.

Achalinus hunanensis sp. nov. is currently only known from Hunan Province, China: Hecheng District, Huaihua City and Ningxiang County, Changsha City (880-1020 m a.s.l.). The holotype was found at night, near a mountain stream (AT 24 °C, RH 80%) with shrubs under subtropical evergreen broadleaves forest. It was moving from leaf litter to the stream. Earthworms were found at the same place, which we speculated as its prey ( Shu et al. 2014).

Figures

Figure 4. The holotype (CIB 119039, subadult male) of Achalinus hunanensis sp. nov. A dorsolateral view B ventral view C right side of middle body view D dorsal head view E left side of head view F right side of head view G ventral head view. Photographs by SCS.

Figure 5. The paratype (CIB 119040, subadult male) of the Achalinus hunanensis sp. nov. A dorsolateral view B ventral view C dorsal head view D right side of head view E ventral head view. Photographs by SCS.