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

Xie, Yanyuan, Li, Yuhui, Wu, Zhengjun & Chen, Zening, 2025, First record of Achalinus hunanensis Ma, Shi, Xiang, Shu & Jiang, 2023 (Serpentes, Xenodermidae) in Guangxi, China, with supplementary morphological information, Biodiversity Data Journal 13, pp. e 168622-e 168622 : e168622-

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

Materials

Type status: Other material. Occurrence: catalogNumber: GXNU 20240905009 ; individualCount: 1; sex: female; occurrenceID: 182A6960-3B27-56D2-B35E-40C1433E1BC4; Taxon: scientificName: Achalinus hunanensis; order: Squamata; family: Xenodermidae; genus: Achalinus; Location: country: China; stateProvince: Guangxi; county: Rongshui Miao Autonomous; verbatimElevation: 891 m; verbatimCoordinates: 25°12.99'N 108°40.81'E; Event: eventDate: 28-08-2024

Type status: Other material. Occurrence: catalogNumber: GXNU 2024090120 ; individualCount: 1; sex: female; occurrenceID: DCB238DB-23AA-5ABC-AF22-68A659E8E4AB; Taxon: scientificName: Achalinus hunanensis; order: Squamata; family: Xenodermidae; genus: Achalinus; Location: country: China; stateProvince: Guangxi; county: Rongshui Miao Autonomous; verbatimElevation: 1281 m; verbatimCoordinates: 25°26.00'N 109°09.65'E; Event: eventDate: 30-08-2024

Type status: Other material. Occurrence: catalogNumber: GXNU 2024102112 ; individualCount: 1; sex: male; occurrenceID: E152E3EE-B346-50C1-83C7-5DDB57E948EB; Taxon: scientificName: Achalinus hunanensis; order: Squamata; family: Xenodermidae; genus: Achalinus; Location: country: China; stateProvince: Guangxi; county: Rongshui Miao Autonomous; verbatimElevation: 983 m; verbatimCoordinates: 25°13.24'N 108°40.58'E; Event: eventDate: 15-10-2024

Description

The description is based on the specimens from Guangxi. The measurements and scalation characters of A. hunanensis are listed in Table 2 . Body slender, cylindrical; head slightly distinct from neck; eye small; triangular, slightly visible from above; length of the suture between the internasal substantially longer than that between prefrontal, with LSBI / LSBP ratios> 1; nostril positioned in anterior part of nasal, deeply concave inwards; prefrontals paired; frontal pentagonal, pointed to the rear, slightly wider than high, much shorter than the parietals; loreal one, subrectangular, with LorH / LorL ratios <1; supraocularone, Irregularly hexagonal; TEMP 7 / 7, arranged in three rows (2 + 2 + 3 on both sides), the anterior two contact the eye; the upper one smaller, irregularly quadrilateral, the lower one elongated; six supralabials, the fourth and fifth contacting the eye, the last one much elongated; two pairs of chin shields, the anterior pairs almost equal to the posterior pairs ( GXNU 2024102112 left two scales, right three scales and the second pair on the right side divided into two smaller scales), followed by preventrals; one mental, followed by 5 / 5 infralabials, the first one contacting with others after the mental and before the 1 st chin-shields, 1 st - 3 rd touching the first pair of chin-shields.

Dorsal scales strongly keeled, lanceolate, 23 rows throughout the body, the outermost row strongly keeled and substantially enlarged. Female GXNU 20240905009 : VS 173, SC 61; Male GXNU 2024102112 : VS 163, SC 71; anal entire; subcaudals unpaired.

In life, specimens display iridescent, uniformly brownish-black dorsal colouration, with a distinctive occipital bright patch extending to the head and abdomen in the two females from Guangxi (absent in males). The first chin shield pair black and second pair brown in the two females (uniformly brownish-black in males). The ventral surface is lighter brownish-black than the dorsum, with the supralabials and infralabials the darker dorsal colouration. Head scales are similar to the body colour. Ventral scale margins are greyish-white. Eyes are completely black with a vertically subelliptic pupil (Fig. 2 ).

In preserved specimens, the dorsum remains taupe and the venter fades to pale brownish-grey, darkening towards the caudal tip (Fig. 3 ).

Distribution

Achalinus hunanensisis is known from the following localities: Guangxi (Rongshui Miao Autonomous County), Hunan Province (Anhua County, Hecheng District, Ningxiang County) and Guizhou Province (Dushan County) (Fig. 1 ). The surrounding habitat, typical for all Achalinus hunanensis, comprises montane evergreen broadleaf forest (elevation 891-1281 m) with the ground covered by leaf litter (Fig. 4 ).

Notes

In the present study, the female specimens exhibit a broad white neck band that is widening towards the venter and extends to the chin region. This feature is unique to females in this study and has not been reported in previous specimens. Additionally, differences were observed in specific morphometric and scalation characteristics. For instance, the examined male specimen has a relatively larger body size (total length: 456 mm vs. 262-379 mm; tail length: 106 mm vs. 58-91 mm in previously reported males). The LSBI / LSBP ratio in this study was also lower (1.68-1.85 vs. 2.00- 2.11 in previous studies). The male specimen in our study exhibits an unusual chin shield configuration: five scales in total (left side with two scales, right side with three scales), featuring normally developed first pairs, while the second pair on the right side are divided into two smaller scales. The main morphological characteristics of A. hunanensis are summarised in Table 2 .

Revised diagnosis and variation of the species

(1) Dorsal scales strongly keeled, 23 rows throughout; (2) tail relatively short, TAL / TL ratio 0.22-0.24 in males and 0.17-0.19 in females; (3) maxillary teeth 23; (4) length of suture between internasals substantially longer than that between prefrontals, LSBI / LSBP ratio 1.68-2.11; (5) one loreal, subrectangular; (6) six supralabials, the fourth and fifth in contact with the eye; (7) the two anterior temporals in contact with eye; (8) ventrals 163-168 in males and 169-173 in females; (9) subcaudals 69-72 in males and 53-61 in females, not paired; (10) Some female specimens exhibit a distinctive occipital bright patch extending to the head and abdomen.

Figures

Figure 1. Distribution of Achalinus hunanensis. The squares indicate the type localities in Hunan, the triangle representing locality in Guizhou and the star marking the sampling site in the present study. Elevation data source: CGIAR-CSI SRTM v. 4.1.

Figure 2. Achalinus hunanensis in life, A 1, A 2 GXNU 20240905009, adult female; B GXNU 2024102112, adult male; C GXNU 2024090120, adult female; photos by Li Ding.

Figure 3. Achalinus hunanensis. A GXNU 20240905009, female; B GXNU 2024102112, male, preserved specimens: 1, ventral view; 2, dorsal view; 3, dorsal head; 4, ventral head; 5, right view of head; 6, left view of head; 7, ventral middle body; 8, lateral middle body. Photos by Yan-Yuan Xie.

Figure 4. Habitats of Achalinus hunanensisis in Jiuwanshan National Nature Reserve, Guangxi; evening (A) and night (B); photos by Li Ding.