Hebius maximus (Malnate, 1962) Li & Ren & Huang & Lyu & Qi & Jiang & Wang & Li, 2022

Li, Mao-Liang, Ren, Jin-Long, Huang, Jun-Jie, Lyu, Zhi-Tong, Qi, Shuo, Jiang, Ke, Wang, Ying-Yong & Li, Jia-Tang, 2022, On the validity of Hebius sauteri maximus (Malnate, 1962) (Squamata, Natricidae), with the redescription of H. maximus comb. nov. and H. sauteri (Boulenger, 1909), Herpetozoa 35, pp. 265-282 : 265

publication ID	https://dx.doi.org/10.3897/herpetozoa.35.e94920
publication LSID	lsid:zoobank.org:pub:29C2ED3F-BC5E-45E7-8E58-FCC93B988455
persistent identifier	https://treatment.plazi.org/id/0DAD6FC8-D410-5F53-8956-9C8E43905A6B
treatment provided by	Herpetozoa by Pensoft
scientific name	Hebius maximus (Malnate, 1962)
status	comb. nov.

Treatment

Hebius maximus (Malnate, 1962) comb. nov.

Figs 2 View Figure 2 , 3 View Figure 3 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11 View Figure 11

Amphiesma sauteri maximus Malnate, 1962, Proc. Acad. Nat. Sci. Philadelphia, 114, 251-299. Type locality: "Hsaioyangchi, Szechwan, China." (= Xiaoyangxi, Mabian Yi Autonomous County, Leshan City, Sichuan Province, China)

Natrix sauteri - Pope 1935: 125 (in part); Wu 1985: 209 (in part).

Amphiesma sauteri maximus - Malnate 1962: 272.

Amphiesma sauteri - Inger et al. 1990: 20; Zhao and Adler 1993: 228 (in part); Zhao et al. 1998: 80 (in part); Zhao 2003: 140; David et al. 2007: 60 (in part); Wallach et al. 2014: 33 (in part).

Hebius sauteri - Guo et al. 2014: 428 (in part); David et al. 2021 (in part).

Types.

Holotype. FMNH 18796 (formerly CHNM 18796), a 457 mm adult female specimen (Fig. 7 View Figure 7 ). Paratypes. FMNH 18797, USNM 71570, USNM 84362.

Referred specimens.

25 specimens of H. maximus were examined in this study: CHINA (n = 25) - Sichuan Prov. CIB 118635, Pingshan County, Mt. Laojun near the type locality; CIB 8451-8452, CIB 8455, CIB 8464, CIB 8467, CIB 8470-8471, Emeishan City, Mt. Emei; CIB 8458, Yingjing County; CIB 8457, Hongya County; CIB 118518, CIB 107645-646, CIB 107649, Dayi County; YBU 18170, Dujiangyan City; CIB 94215-94216, Mianyang City. - Chongqing. CIB 8448, Youyang Tujia & Miao Autonomous County; YBU 11258, Xiushan Tujia & Miao Autonomous County. - Guizhou Prov. CIB 8482, SYS r002041, CIB 8484, CIB 118072-118074, Bijie City, Qixingguan District.

Diagnosis.

Hebius maximus comb. nov. can be distinguished from its congeners by the following morphological characters: (1) body size small to medium, maximum ToL 597 mm; (2) dorsal scales rows 17-17-17, all weekly keeled or smooth at outmost one or two rows; (3) ventral scales 132-143, cloacal plates divided, subcaudals 64-92, paired; (4) maxillary teeth 24, last two distinctly enlarged, without diastema; (5) supralabials 7-8; (6) infralabials 7-9, generally edged with black at posterior border on 1st-3rd scales only; (7) a light orange stripe extends from angulus oris to the neck; (8) dorsal body reddish brown or grayish brown, with an ill-defined dark olive streak scattered with black spots extending from neck to end at medium of the dorsal.

Description.

Body elongated, small to medium-sized, ToL 175-597 mm (260-470 mm in males, 175-597 mm in females); tail relatively long, TL/ToL 0.25-0.33 (0.25-0.33 in males, 0.25-0.31 in females). Eye large, pupil round.

Dentition. Maxillary teeth 24, without diastema, gradually enlarged posteriorly, last two distinctly enlarged.

Body scalation. Dorsal scales in 17-17-17 rows, weekly keeled except outer 1-4 rows at anterior body, outer 0-2 rows smooth at midbody and outer 0-1 row smooth posteriorly; ventrals 132-143 (132-138 in males, 135-143 in females); cloacal plates divided; subcaudals 64-92 (72-92 in males, 64-82 in females), paired.

Head scalation. Rostral broad, visible from above; internasals paired, nearly triangular, curved outwards, not bordering loreal; prefrontals paired, nearly in a diamond shape, wider than long, borders the loreal, preocular, and supraocular; frontal hexagonal, longer than wide, embedded into parietals posteriorly; parietals paired, not bordering preocular; nasals wider than high, divided at lower half, borders 1st-2nd supralabials; loreal single, borders 2nd or 2nd-3rd supralabials, not entering orbit; preocular single, higher than wide, rarely divided (CIB 8484, CIB 8467, SYS r002041); supraocular single, narrowed anteriorly, much wider than high; postoculars 2-3; supralabials 7-8, 6th or 7th highest, 3rd-4th or 4th-5th entering orbit; temporals 1-2 + 1-3 + 0/2-4; infralabials 7-9, first pair in contact behind the mental, IfL 1-3, 1-4 or 1-5 border the anterior chin shields; chin shields paired, posterior pair longer (Figs 3 View Figure 3 , 8 View Figure 8 , Table 4 View Table 4 ).

Hemipenis. The description of hemipenis based on an adult specimen (CIB 118635) near the type locality, Yibin, Sichuan, southwestern China. The left side of hemipenis fully everted, whereas the right side remained in situ for description of retracted condition.

Hemipenis thin and short, hemipenial total length (HTL) 7.14 mm, hemipenial total width (HTW) 1.57 mm. HTL/HTW 4.55; Y-shaped, shallowly bilobed, hemipenial truncus length (HCL): 5.75 mm, HCL/HTL 0.81. Both sulcate and asulcate surfaces densely ornamented with spinules, a large basal hook present at the proximal part. Sulcus spermaticus single, extending to base of inner right lobe where it takes a centripetal position. Sulcus lip highly developed and raised, walls covered with spinules (Fig. 10 View Figure 10 ).

In situ hemipenis extends up to 5thSC with its crotch extending to 4thSC; crotch of m. retractor penis magnus extending to 6thSC, origin of m. retractor penis magnus invariably at level of 20thSC.

Coloration in life.

Based on one male adult specimen near the type locality (CIB 118635). Dorsal side of head reddish brown with irregular dark and olive spots above; ventral side of head cream white; 1st-6th supralabials whitish with dark edges on posterior part; 7th supralabial reddish-brown at upper part and white with dark edge at lower part, 8th supralabial cream white, gradually turning to orange posteriorly; infralabials white, edged with black on posterior border on 1st-3rd scales only; an orange stripe extends from angulus oris to dorsal side of neck, two scales wide; dorsal body and tail reddish-brown with an ill-defined dark olive dorsal streak scattered with black spots extending from neck to tail, lateral with a series of orange spots separated by 2-3 scales on 4th-5th body scale rows, gradually faded posteriorly; ventral and subcaudal cream white with black spots on outer edge of each scale; sclera yellow with black round pupil (Fig. 8 View Figure 8 ).

Coloration in preservative.

Largely the same as in life except dorsal head brown to seal brown, with or without irregular dark spots; supralabials cream white to pale gray, 1st-6th supralabials with black edge or spots posteriorly, upper half of the highest supralabial brown to black; a pale orange to yellow short stripe extends from angulus oris to neck; dorsal of body and tail brown to seal brown, slightly darker posteriorly, with or without a series of white spots or short band separated by 2-3 scales on 4-6 body scale rows; ventral and subcaudal cream white to pale grey; sclera black (Fig. 9 View Figure 9 ).

Sexual dimorphism.

Males H. maximus comb. nov. exhibit a lower number of ventral scales [132-138 (136 ± 2) in male vs. 135-143 (138 ± 3) in female] and a higher number of subcaudal scale counts [72-92 (81 ± 6) in male vs. 64-82 (72 ± 5) in female] than female (n = 13 male and 12 female) (Tables 4 View Table 4 , 5 View Table 5 ).

Comparison.

Hebius maximus comb. nov. differs from H. andreae , H. annamensis , H. arquus , H. beddomei , H. bitaeniatus , H. boulengeri , H. celebicus , H. clerki , H. concelarus , H. craspedogaster , H. deschauenseei , H. flavifrons , H. groundwateri , H. igneus , H. inas , H. ishigakiensis , H. johannis , H. kerinciensis , H. khasiensis , H. lacrima , H. leucomystax , H. metusia , H. miyajimae , H. modestus , H. monticola , H. nicobariensis , H. octolineatus , H. optatus , H. parallelus , H. petersii , H. popei , H. pryeri , H. sangzhiensis , H. sanguineus , H. sarasinorum , H. septemlineatus , H. vibakari , H. viperinus , H. weixiensis , H. xenura and H. yanbianensis by having 17-17-17 dorsal scale rows vs. 19-19-17 rows.

Hebius maximus comb. nov. differs from H. chapaensis , H. frenatus , H. nigriventer , H. sarawacensis and H. taronensis by (1) maxillary teeth 24 vs. 29-34 in H. chapaensis , 28-33 in H. nigriventer , 28-32 in H. taronensis ; (2) ventrals 132-143 vs. 159-177 in H. chapaensis , 164-166 in H. frenatus , 155-168 in H. nigriventer , 145-150 in H. sarawacensis , 158-176 in H. taronensis ( Peters 1871; Malkmus et al. 2002; David et al. 2005; David et al. 2015; Purkayastha and David 2019; David et al. 2021).

Hebius maximus comb. nov. differs from H. atemporalis by (1) temporals present, supralabial not in contact with parietal vs. usually absent or a small triangular temporal between postocular and supralabial, supralabial in contact with parietal; (2) maxillary teeth 24 vs. 27-32 ( Bourret 1934b; Zhao et al. 1998; Table 4 View Table 4 ).

Lastly, H. maximus comb. nov. was previously confused with H. sauteri , H. maximus differs from the latter species in having (1) more ventrals, 132-138 in male, 135-143 in female vs. 125-130 in male, 116-133 in female; (2) more ventrals + subcaudals counts, 207-225 vs. 187-215 (3) fewer maxillary teeth 24 vs. 23-27 ( Zhao et al. 1998; this study); (4) infralabials white edged with black at the posterior border usually on 1st-3rd scales only vs. white with black edge between each scale (Fig. 3 View Figure 3 , Tables 4 View Table 4 , 5 View Table 5 ).

Etymology.

Hebius maximus comb. nov. is named for its highest count of ventral scales among three previous subspecies of H. sauteri ( Malnate 1962). Since Hebius maximus comb. nov. is mainly distributed in southwestern China (Sichuan, Chongqing, and Guizhou), we suggest its common name as "Western China Keelback" in English and “Huá Xī Fù Liàn Shé ( 华西腹链蛇)” in Chinese.

Natural history.

Hebius maximus comb. nov. inhabits subtropical mountain regions around 812-1,200 m above sea level, including coniferous forest and large forest clearings ( Inger et al. 1990; This study). One specimen near the type locality (CIB 118635) was found on a road near a stream at dusk, emerging from a cornfield. The species is diurnal and is active at dusk; it has been reported to prey on earthworms, slugs, and tadpoles ( Wu et al. 1985; Zhao 2006). Oviparous, Pope (1935) reported five well-developed eggs inside with very small embryos in one specimen (USNM 84362) from Chouchiakou (= Zhoujiakou), Suchow (= Yibin City), Sichuan, China, while Inger et al. (1990) reported two females collected from Washan, Sichuan had one enlarged egg in each ovary. The specimens of H. maximus comb. nov. we collected exhibit no tendency to bite when handled. Hebius maximus comb. nov. is found sympatric with Cyclophiops major , Achalinus spinalis , Protobothrops mucrosquamatus , Lycodon ruhstrati , Rhabdophis tigrinus , Sphenomorphus indicus , Rana omeimontis , Odorrana graminea and Bufo gargarizans in field observations during fieldwork conducted in Yibin, Sichuan, China (Fig. 11 View Figure 11 ).

Distribution.

Hebius maximus comb. nov. is currently known to be distributed in southwestern China, including Chongqing (Youyang Tujia & Miao Autonomous County, Xiushan Tujia & Miao Autonomous County), Sichuan (Mabian County, Pingshan County, Yingjing County, Hongya County, Dujiangyan City, Mianyang City, Leshan City) and Guizhou (Qixingguan District, Bijie City) (this study; Wu 1985) (Fig. 2 View Figure 2 ).