Hebius malnatei Li, Nguyen, Huang, Poyarkov, David, Li & Ren 2026, sp. nov.

Hebius malnatei Li, Nguyen, Huang, Poyarkov, David, Li & Ren sp. nov. Chresonymy. Natrix atemporalis — Wu (1985: 171, in part) Amphiesma atemporale — Wallach et al. (2014: 28, in part) Amphiesma atemporalis — Zhao and Adler (1993: 225, in part); Zhao et al. (1998: 52, in part); Zhao (2006: 45 in part); Yang and Rao (2008: 252, in part) Hebius atemporale — Guo (2014, in part) Hebius atemporalis — David et al. (2021: 54, in part) Holotype. CIB 122551, adult female, from Pugu Village, Panzhou County, Liupanshui City, Guizhou Province, China (26.0564°N, 104.7504°E; elevation 1,750 m a. s. l.), collected on 12 May 2024, collected by locals. Paratypes. (n = 5, all from China). CIB 122558 (subadult female) from Panlong District, Kunming City, Yunnan Province (25.1430°N, 102.7486°E); CIB 122557 (adult male), CIB 101974 (adult male), CIB 122552 (adult female) from Mengzi City, Honghe Prefecture, Yunnan Province; and CIB 122550 (adult female) from Pugu Village, Panzhou County, Liupanshui City, Guizhou Province. Additional specimens. (n = 6, all from Yunnan Province, China). CIB 122553 (adult female), CIB 122554 (adult female), CIB 122555 (subadult female) from Mengzi City, Honghe Prefecture; YBU 14259 (subadult female) from Mingjiu Town, Mengzi City, Honghe Prefecture; CIB 122556 (juvenile, sex unknown) from Panlong District, Kunming City; and CIB 72560 (subadult male) from Yunnan Province (exact locality unknown). Diagnosis. Hebius malnatei sp. nov. is distinguished from all congeners by the following combination of characters: (1) small body size, maximum snout-vent length 416 mm; (2) head small, narrow, and moderately distinct from neck; (3) maxillary teeth 26–29, gradually enlarged posteriorly; (4) supralabials 6 (rarely 5), with the 3 rd and 4 th entering the orbit; (5) temporal scale absent or represented by a small narrow scale; (6) infralabials 7 (rarely 6); (7) dorsal scale rows 17-17 - 17, weakly keeled except for the outermost 1–6 rows; (8) ventrals 146–156 with two preventrals; (9) subcaudals 60–70, paired; (10) ventral surface of head white, scattered with black spots or streaks; (11) sutures of infralabials strongly edged in black; (12) a white to orangish nuchal collar absent; (13) dorsal ground color gradually changing from brown to dark olive, usually with a series of discontinuous light spots along the lateral side, forming an inconspicuous stripe; (14) tail relatively short (TaL / SVL ratio 0.22–0.27). Description of the holotype. (Table 1, Figs 6, 7). Head narrow and elongate, subrectangular, distinctly separated from neck, with a slight flattening anterior to the eyes, HL / HW 1.78; snout short, slightly longer than the horizontal diameter of the eye, slightly flattened and narrowing anteriorly, tip nearly blunt in dorsal view and rounded in lateral view with a well-defined canthus rostralis; eyes relatively large, diameter clearly exceeding vertical distance from its lower margin to edge of upper lip, pupil round; body relatively slender and subcylindrical; tail cylindrical, long, and thin, tapering progressively toward the tip. Dentition. Maxillary teeth 26, without diastema, gradually enlarged posteriorly. Body size. SVL 379 mm; TaL 112 mm; TL 491 mm; ratio TaL / TL = 0.23. Body scalation. Dorsal scales in 17-17 - 17 rows, most scales smooth, with feeble keels present except outer six rows at anterior body and outer four rows at mid and posterior body, becoming more distinct along the mid-dorsum, scales of the 1 st dorsal row enlarged; apical pits absent; ventrals 151, preceded by 2 preventrals; cloacal plate divided; subcaudals 63, all paired. Head scalation. Rostral rectangular, wider than high, slightly visible from above (anterior margin partly damaged); nasal large, rectangular, distinctly longer than high, divided into anterior and posterior sections, bordered by first two supralabials, rostral, internasal, and prefrontal, nostril round, piercing anterior edge of posterior section of nasal; internasals two, subrectangular, slightly curved, slightly wider than long, in contact with rostral anteriorly, nasals laterally, and prefrontals posteriorly; prefrontals two, large, subrectangular, shorter than frontal, clearly visible in lateral view, each in contact with internasal, nasal, preocular, loreal, and frontal; frontal hexagonal, elongate, tapering posteriorly, about 1.5 times as long as wide, equal in length to distance from tip of snout to its anterior margin; parietals elongate, longer than wide, in broad medial contact, length slightly exceeding that of frontal; supraoculars 1 / 1, distinctly longer than wide, in contact with prefrontals; loreals 1 / 1, small, rectangular, not entering orbit, bordered by the second supralabial; preoculars 1 / 1, large, more than twice as high as wide, broadly in contact with the prefrontal; subocular absent; postoculars 2 / 2, arranged vertically, decreasing in size from dorsal to ventral; temporals 1 + 1 / 0 + 1, anterior temporal on right side narrow, not entering orbit, sharply pointed posteriorly, bordered by 5 th supralabial and parietal, posterior temporal fan-shaped, bordered dorsally by parietal and ventrally by 5 th and 6 th supralabials on right side and separated from 6 th supralabial by a small fan-shaped scale situated between temporal and 6 th supralabial on left side; supralabials 6 / 6, first and second in contact with nasal, second also contacting loreal, third to fourth entering orbit, fifth largest, in contact with parietal; infralabials 7 / 7, first pair in broad medial contact, first to fourth in contact with anterior chin shields; posterior chin shields longer than anterior chin shields, separated medially by two small scales. Coloration. In life, dorsal surface of head dark brown with irregular lighter mottling on rostral and internasals; snout light brown; supralabials cream white, first to fourth with grey to black pigmentation on the upper and lateral surfaces, fifth with the right half concolorous with the dorsal head, sixth bordered by a distinct dark-grey margin; dorsal coloration of body and tail gradually changes from brown on the anterior body to dark olive at posterior body and tail, slightly lighter laterally, a serious of light orangish spots, continuous or separated by one or two dorsal scales, present on four to six body scale rows from neck to tail tip, gradually smaller and vaguer posteriorly, forming an indistinct lateral stripe, faint and irregular darker spots indistinctly visible along body and tail; ventral surface of head cream white, with irregular black spots and streaks along the edges of chin shields and adjacent small scales; infralabials cream white, sutures conspicuously black-edged, the first to third densely scattered with grey to black dots, fourth to seventh black on the upper edge and sparsely dotted with black; ventral surface of neck and anterior body faint yellow gradually transitioning to white on posterior body and tail, the lateral margins of the ventral scales concolorous with the dorsal scales, a series of indistinct small black spots present along each side of the ventrals, forming a chain-like pattern; subcaudals cream white with dark brown mottling, forming irregular lateral patches toward the tail tip. In preservative, coloration resembles the living status, except the dorsal coloration become darker and ventral of head, body, and tail are uniformly pale white. Variation (Fig. 7). Measurements and scalation data for the type series and additional specimens are summarized in Table 1. Snout-vent length 139–416 mm; tail length 47–125 + mm (0.22–0.27 of total length). Maxillary teeth 26–29. Dorsal scale rows weakly keeled on 7–15 upper rows at midbody. Postoculars 2–3; anterior temporal variable, 1 / 0, 0 / 1 or 0 / 0; supralabials usually 6 (rarely 5), with the 3 rd and 4 th entering the orbit; infralabials 6–7 (rarely 5 / 5 in CIB 122555), with the first four contacting the anterior chin shields; ventrals 146–156; subcaudals 60–70, all paired. Coloration generally matches the holotype with the following variations: (1) some individuals (e. g. CIB 122554) exhibit a more brownish dorsal head compared to the dorsal body; (2) the degree of ventral head spotting varies slightly, with some specimens (e. g., CIB 122550) exhibiting denser pigmentation whereas others (e. g., CIB 72560) display only faint, obscure markings; (3) the ventral surfaces of the body and tail sometimes bear scattered black margins on ventral and subcaudal scales, with black spots along the lateral edges of ventral scales being more distinct in certain specimens (e. g., CIB 122555). Comparisons. The main diagnostic characters distinguishing Hebius malnatei sp. nov. from the 37 other congeners recorded from China and the Indo-Burma region (Vietnam, Laos, Cambodia, Thailand, and Myanmar) are summarized in Suppl. material 1: table S 4. The new species is readily distinguished from all congeners by the frequent absence or extreme reduction of the anterior temporal scale to a minute or vestigial form; all other species possess one or two well-developed anterior temporals, except H. atemporalis, which also lacks this character. Hebius malnatei sp. nov. differs from H. andreae (Ziegler & Le), H. bitaeniatus (Wall), H. boulengeri (Gressitt), H. clerki (Wall), H. craspedogaster (Boulenger), H. deschauenseei (Taylor), H. gilhodesi (Wall), H. groundwateri (Smith), H. igneus David, Vogel, Nguyen, Orlov, Pauwels, Teynié & Ziegler, H. inas (Laidlaw), H. jingdongensis Ma, Shi, Ayi & Jiang, H. johannis (Boulenger), H. leucomystax (David, Bain, Nguyen, Orlov, Vogel, Vu & Ziegler), H. metusia (Inger, Zhao, Shaffer & Wu), H. miyajimae (Maki), H. modestus (Günther), H. octolineatus (Boulenger), H. optatus (Hu & Zhao), H. popei (Schmidt), H. sangzhiensis Zhou, Qi, Lu, Lyu & Li, H. septemlineatus (Schmidt), H. shantianfangi Liu, Wang, Hou, Zhang, Wang, Zong, Zhou, Rao, David & Vogel, H. terrakarenorum Hauser, Smits & David, H. vibakari (Boie),