Pareas Boulengeri (Angel, 1920)

Amblycephalus Boulengeri (Angel, 1920).

Amblycephalus monticola boulengeri (Mell, 1931).

Pareas boulengeri (Hu et al. 1973; Zhao et al. 1998, Chen et al. 2006; Guo and Deng 2006; Zhao 2006; Wallach et al. 2014; Vogel 2015).

Pareas (Eberhardtia) boulengeri (Poyarkov et al. 2022).

Type locality.

Région de Koeï Tchéou, Chine. ” [= Guizhou region, southeastern China, ca. 27°N, 107°E].

Syntypes.

MNHN-RA 1912.0349 (470 mm specimen), MNHN-RA 1912.0350 (82 mm specimen), and MNHN-RA 1912.0351 (460 mm specimen) (Révérend Père avalerie).

Specimens examined.

Nine specimens were assessed (3 females and 6 males); all were molecularly identified as the species Pareas boulengeri. Four of the specimens were obtained from Liupanshui Normal University in Shuicheng City, Guizhou Province, China, with the following identifiers: LPSSY 2024070903 (male), LPASY 2022070601 (male), LPSSY 2021070801 (female), and LPSSY 2024070902 (female). One specimen was collected from the Shuicheng District of Liupanshui City: LPSSC 2024070502 (female). One specimen was obtained from Yushe National Forest Park in Shuicheng City, Liupanshui City: LPSYS 2022062802 (female). The remaining three specimens were obtained from Huangping County, Qiandongnan Miao and Dong Autonomous Prefecture, Guizhou Province: GZNU 20180515017 (female), GZNU 2018052303 (male), and GZNU 2018052302 (male).

Common name.

The common English name is Boulenger’s Slug Snake; the common Chinese name is 平鳞钝头蛇 (Píng Lín Dùn Tóu Shé).

Etymology.

Revised diagnosis: Pareas boulengeri can be distinguished from its congeners by a combination of the following characteristics (Fig. 3): (1) medium body size (TL 308–566 mm, n = 5 females; 362–565 mm, n = 6 males); (2) gray – brown or tan body, with many dorsal scales and covered with dark brown spots; (3) length of suture between internasals is distinctly shorter than that between the prefrontals, with a prefrontal bordering orbit; (4) frontal is subhexagonal to diamond-shaped, with its lateral sides converging posteriorly; (5) anterior pair of chin shields is longer than broad, with the loreal bordering the orbit; (6) the prefrontal contacts the eye, and there is one subocular scale with no preocular scales; (7) 7–8 supralabials and 9 infralabial scales; (8) rows of 15-15 - 15 dorsal scales, mid-dorsal scales smooth, and the vertebral scale row is not enlarged; (9) 175–188 ventrals scales, 57–66 subcaudals scales, divided, with a single cloacal plate; (10) prefrontal and postfrontal bones exhibit contact, asymmetric teeth number in maxilla, palatine, pterygoid, and dentary bones (MX 4–5 / 5, PAL 3 / 3, PT 9–13 / 9 – 11, DT 16–18 / 20 – 21); (11) dorsal surface of the head displays a dense configuration of black, coarse spots; two black longitudinal stripes extend posteriorly, located behind the parietal and supraocular scales, converging into a prominent black stripe in the neck region; a slender black horizontal line is present on the lateral aspect of the head, posterior to the eye and extending toward the corner of the mouth.

Remarks.

The type locality of Pareas boulengeri is in the “ Région de Koeï Tchéou, Chine ” [= Guizhou region, southeastern China, approximately 27°N, 107°E], according to the original description; however, the specific locus remains unknown. Subsequently, this species has been reported from multiple localities in central, eastern, and southern China (Zhao et al. 1998; Chen et al. 2006; Guo and Deng 2006). However, based on voucher specimens and molecular data from this study, P. boulengeri is currently only within Chongqing, Hunan, Guizhou, Hubei, and Sichuan. The populations in southern Gansu and southern Shaanxi are temporarily classified as P. boulengeri. Previous records from the Dabie Mountains, at the junction of Anhui, Henan, and Hubei, should be assigned to P. dabieshanensis sp. nov. (Chen et al. 2006; Pan et al. 2014; this study), while previous records from southern Anhui, Jiangxi, and Zhejiang should be assigned to P. orientalis sp. nov. (this study).