Fowlea yunnanensis (Anderson, 1879)

Atretium schistosum var. yunnanensis Anderson 1879: 822

Helicops schistosus var. andersonii Wall 1909

Helicops schistosus yunnanensis — Mell (1931)

Helicops yunnanensis — Pope (1935)

Atretium yunnanensis — Smith (1943); Wallach et al. (2014)

Fowlea yunnanensis — Cheng et al. (2021); Deepak et al. (2021)

Lectotype (hereby designated): ZSI-R-4192, adult female, from Hotha, now Husa, Longchuan County, Dehong Dai and Jingpo Autonomous Prefecture, Yunnan Province, China; collected during the Yunnan Expedition, 1868.

Paralectotypes (Fig. 1, F-G): ZSI-R-4191, adult female, and ZSI-R-4196, adult male from Muangla, now Jiucheng, Yingjiang County, Yunnan Province, China; collected during the Yunnan Expedition, 1868.

Diagnosis. Based on Cheng et al. 2021 and the present study this species is characterized by: body cylindrical; dorsal scale rows 19–19–17, keeled; ventrals 138–151; subcaudals 65–89, paired; internasals 2–3, triangular; prefrontals 2 (rarely 3–4, only in the case of two paralectotypes); postoculars 3 (rarely 4); supralabials 9 (rarely 8), 4 th –5 th entering orbit; infralabials 10 (rarely 9); hemipenis bilobed, longitudinal folds present, papillae present on the apex of both lobes; lateral sides of the head having two black, oblique, parallel stripes that are either absent or vague; olive brown with a black reticulate pattern on the dorsal surface and creamish-white on the ventral surface.

Description of the lectotype of Fowlea yunnanensis (Fig. 1, B–E). An adult female, in a relatively good state of preservation after more than 157 years in ethanol.

Morphology. Snout-vent length 449 mm, tail length 157 mm, total length 606 mm, ratio tail length/total length 0.26. Head moderately large (head length 24.8 mm, head width 12.0 mm), distinct from neck; snout broad, obtuse as seen from above; eye large (eye diameter 3.6 mm, eye-snout distance 6.1 mm, eye-nostril distance 3.9 mm); pupils round; nostrils crescent shaped, piercing in the middle of the nasal, oriented dorsolaterally.

Body scalation. Dorsal scales in 19–19–17 rows; scales keeled, notched at apex; Dorsal scale rows reduction: scales around the body reduced from 19 to 17 by fusion of 3 rd and 4 th rows of dorsal scales at the levels of the 83 rd ventral on the right side and 82 nd ventral at left side; 151 ventrals (plus three preventrals); cloacal plate divided, right side over the left side; 83 subcaudals, paired.

Head scalation. Rostral wider than high, wide, approximately twice as wide as high, visible from above; nasals slightly elongate, completely divided by a suture; nostrils located in the middle of nasals; internasals subtriangular, in broad contact with each other, not in contact with loreal, about as long as wide, distinctly narrowing anteriorly; 2 prefrontals, pentagonal, slightly broader than long; prefrontal sutures slightly longer than length of internasal sutures; frontal elongate, more than twice as long as prefrontal; supraocular 1/1, elongate, narrowing anteriorly, parietals in broad contact with each other, parietal suture longer than the length of frontal. Loreal 1/1, small, longer than broad, in contact with 2 nd –3 rd supralabials, not entering orbit; preoculars 1/1, longer than broad; postoculars 3/3; supralabials 9/9, 4 th –5 th entering orbit, 8 th largest in left side and 7 th in right side; temporals 2+2 on both sides; mental subtriangular, wide; 10/10 infralabials, first pair in contact with each other behind mental, 1 st –5 th in contact with anterior chin shields; two pairs of chin shields; posterior chin shields longer than anterior ones, separated from each other by small scales.

Variation in paralectotypes. Both paralectotypes agree in all aspects with the lectotype except, ventrals 141–149, internasals 3, and prefrontals 3–4.

Specimens from India and updated distribution of F. yunannensis. We came across seven specimens (bearing a single voucher number ZSI-R-24039) in the Reptilia section of ZSI, which were collected from Gibbon’s land (27.4858° N, 96.2045° E), Namdapha Tiger Reserve, 16 km east of Miao, Miao district, Arunachal Pradesh, India by S. Biswas & party on 22 December 1982 (Fig. 1, A) The specimens were identified as F. yunnanensis based on the following characters (Fig. 1, H–J): body cylindrical; SVL 280–550 mm; dorsal scale rows 19–19–17, keeled (except first row); ventrals 138–149; subcaudals 83–89, paired; internasals 2, triangular; prefrontal 2; postoculars 3; supralabials 9, rarely 8 (in two out of seven specimens, only on one side), 4th–5th entering orbit; infralabials 10 (rarely 9 in one specimen); olive brown with a black reticulate pattern on the dorsal surface and cream white on the ventral surface; oblique, parallel dark stripes on lateral head absent. Based on the voucher specimens, we report the occurrence of Fowlea yunnanensis for the first time from India.

The current records indicate that F. yunnanensis is distributed in southwestern China (Yunnan Province) and northeastern India (Arunachal Pradesh), and it is likely to occur in neighboring areas of Myanmar. However, comprehensive surveys and specimen-based confirmations are required to accurately delineate its distribution across these border regions.