Hebius youjiangensis, Xu & Yang & Gong & Wu & Huang & Liu & Liang & Huang & Huang, 2023
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publication ID |
https://doi.org/ 10.11646/zootaxa.5319.1.5 |
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publication LSID |
lsid:zoobank.org:pub:C15698EF-A99E-431F-9453-FC82FEF0ECC4 |
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DOI |
https://doi.org/10.5281/zenodo.10559213 |
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persistent identifier |
https://treatment.plazi.org/id/2166A771-FFF8-C978-CFAD-FE17FA032B88 |
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treatment provided by |
Plazi |
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scientific name |
Hebius youjiangensis |
| status |
sp. nov. |
Hebius youjiangensis sp. nov. Yang, Xu, Wu, Gong, Huang & Huang ( Figs. 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5 )
Holotype. ANU20220010 View Materials (collection number: HSR22184 ), an adult female, was collected by Jiaxiang Wu and Yongjin Liu, on November 28, 2022, at night, in Daleng Village , Youjiang District , Baise City, Guangxi Zhuang Autonomous Region, China, (23°44′7.01″ N, 106°23′43.21″ E, 780 m a. s. l.), with an air temperature of about 17.6°C. GoogleMaps
Diagnosis. Hebius youjiangensis sp. nov. can be distinguished from its congeners by the following combination of characters: (1) dorsal scale rows 19-17-17, feebly keeled except the outermost rows; (2) tail length comparatively long, TAL/TL ratio 0.30 in females; (3) ventrals 3+160; (4) subcaudals 112; (5) supralabials 9, the fourth to sixth in contact with the eye, the seventh to ninth largest; (6) infralabials 10, the first 5 touching the first pair of chin shields; (7) preocular 1; (8) postoculars 2; (9) temporals 4, arranged in three rows (1+1+2); (10) maxillary teeth 30, the last 3 enlarged, without diastema; (11) postocular streak presence; (12) background color of dorsal brownish black, a continuous beige stripe extending from behind the eye to the end of the tail on 5 th to 7 th scale rows in anterior part of body, and 4 th to 6 th in middle and posterior part of body; (13) anterior venter creamish-yellow, gradually fades to the rear, with irregular black blotches in the middle and outer quarter of ventrals, the posterior part almost completely black.
Description of holotype. The adult female specimen has the following characters: TL 582 mm (SVL 409 mm and TAL 173 mm), tail complete, TAL/TL ratio 0.30. Body elongated and cylindrical; head flattened anteriorly, distinct from the neck, HL 16.95 mm, HW 8.82 mm. Nostril lateral, round, piercing in the middle of the nasal. Eye large, ED 2.3 mm, pupil round. Tail complete, long and tapering.
Body scalation. DSR 19-17-17, feebly keeled posterior to nape, and outermost dorsal scale row on both sides smooth, not notched at their posterior extremity. VEN 160 (+ 3 preventrals); SC 112, all paired; CP divided.
Dorsal scale row reduction.
3+4→3 (76-77) (right)
19———————————17
3+4→3 (75-76) (left)
Dentition. Maxillary teeth 30, gradually enlarging, the last 3 moderately enlarged, without diastema between the last three and the anterior teeth.
Head scalation. Rostral visible dorsally, trapezoidal, wider than high; nasals nearly rectangular, about twice as wide as high, divided into two parts; nostril in the anterior part of the nasal, posterior margin of nostril with a distinct nostril cleft, the posterior section of nasal vertically subrectangle, about half as wide as the anterior part; internasals small, subtriangular, in broad contact with each other, narrowing anteriorly; prefrontals 2, subpentagonal, wider than long, in contact with loreal; frontal narrow, hexagonal, longer than wide, shield-like; supraocular 1/1, much wider than high; LOR 1/1, subrectangular, wider than long; PRO 1/1; PO 2/2, upper one larger than lower one; SL 9/9, the first 2 in contact with nasal, the 2 nd to 4 th in contact with the loreal, 4 th to 6 th entering orbit, the 7 th and 9 th largest; TEMP 4/4, small, slightly rectangular, arranged in three rows (1+1+2); chin shields in 2 pairs, posterior pair longer than anterior ones; IL 10/10, first pair in contact behind the mental, 1 st to 5 th touching the first pair of chin shields, the 5 th and 6 th largest.
Coloration in life. In life, dorsal surface of head is brownish-black, densely covered by irregular and vermiculate brownish yellow or light brown stripes. A thick, obvious beige postocular streak extends backwards to meet with the dorsolateral stripe on each side. A short, pale yellowish-brown streak on the outside of parietals and the vertebral scales behind the parietals. Supralabials ochre yellow, the first seven trailing edges brownish-black, the 8 th upper half and 9 th bottom brownish-black.
Body brownish-black, middle darker than the sides. Dorsal scales of the body brownish-black on both sides, and pale yellowish-brown in the middle. A conspicuous, continuous beige stripe extending from behind the eye to the end of the tail on the upper part of 5 th to the lower part of 7 th scale rows in anterior part of body, and the upper part of 4 th to 6 th in middle and posterior part of body. The upper part of the 1 st DSR in anterior part of body is brownish-black and the lower part is creamish-yellow.
Venter anterior creamish-yellow, gradually fades to the rear, speckled with dark or blackish-brown spots along its middle. The outermost edge of the ventrals is black. Outer quarter of ventrals with subrectangular, black blotches on each side, producing an irregular, continuous ventrolateral stripe. The black blotches gradually deepen and diffuse to the rear, making the posterior part of the venter almost completely black. Ventral surface of the tail glossy, uniform black, free margins of the posterior part of venter scales and subcaudals grayish-white.
Coloration in preservation. After two months of preservation, coloration still resembles the specimen in life, except that the background color of the anterior venter becomes ivory cream.
Etymology. We named this species based on its type locality Daleng Village is adjacent to the Youjiang River, Guangxi Zhuang Autonomous Region, China. The name we suggest is Yòu Jiāng Fù Liàn Shé (Ůĭkńfi) as Chinese common name and Youjiang Keelback Snake as English common name.
Distribution and Habitat. At present, the new species is only found at the type locality of Daleng Village, Youjiang District, Baise City, Guangxi Zhuang Autonomous Region, China. We found the snake between 1:00 to 2:00 am after a light rain, swimming on the hill stream water surface. The habitat environment was well preserved subtropical evergreen broad-leaved forest, at an elevation of 780 m.
Comparisons. Hebius youjiangensis sp. nov. can be differentiated from all other species of Hebius by having the following characters: preoculars, postoculars, supralabials, infralabials, prefrontal, ventrals, subcaudals, and DSR counts; a conspicuous, beige dorsolateral stripe extending from behind the eye to the end of the tail on each side; and the posterior part of venter almost black.
Hebius youjiangensis sp. nov. can be easily distinguished from H. andreae (Ziegler & Le Khac Quyet, 2006) , H. beddomei (Günther, 1864) , H. bitaeniatus ( Wall, 1925) , H. boulengeri ( Gressitt, 1937) , H. celebicus (Peters & Doris, 1878) , H. clerki ( Wall, 1925) , H. concelarus (Malnate, 1963) , H. craspedogaster (Boulenger, 1899) , H. flavifrons (Boulenger, 1887) , H. inas (Laidlaw, 1901) , H. ishigakiensis (Malnate & Munsterman, 1960) , H. johannis (Boulenger, 1908) , H. kerinciensis ( David & Das, 2003) , H. khasiensis (Boulenger, 1890) , H. lacrima Purkayastha & David, 2019 , H. leucomystax (David, Bain, Quang Truong, Orlov, Vogel, Ngoc Thanh & Ziegler, 2007) , H. metusia (Inger, Zhao, Shaffer & Wu, 1990) , H. miyajimae (Maki, 1931) , H. nicobariensis (Sclater, 1891) , H. octolineatus (Boulenger, 1904) , H. optatus (Hu & Zhao, 1966) , H. parallelus (Boulenger, 1890) , H. petersii (Boulenger, 1893) , H. popei (Schmidt, 1925) , H. pryeri (Boulenger, 1887) , H. sanguineus (Smedley, 1932) , H. sangzhiensis Zhou, Qi, Lu, Lyu & Li, 2019 , H. sarasinorum (Boulenger, 1896) , H. septemlineatus (Schmidt, 1925) , H. terrakarenorum Hauser, Smits & David, 2022 , H. vibakari (Boie, 1826) , H. viperinus (Schenkel, 1901) , H. weixiensis Hou, Yuan, Wei, Zhao, Liu, Wu, Shen, Chen, Guo & Che, 2021 and H. yanbianensis Liu, Zhong, Wang, Liu & Guo, 2018 by having 17 DSR at midbody (vs. 19 or 15), and the posterior part of venter almost black.
Hebius youjiangensis sp. nov. is most similar to its sister species H. modestus . However, the new species can be distinguished from H. modestus by having 17 DSR at midbody (vs. 19), maxillary teeth 30, the last 3 moderately enlarged (vs. 27–29 maxillary teeth, the last 2 moderately enlarged), postocular streak presence (vs. absent), and dorsal brownish-black, a conspicuous, continuous beige stripe extending from behind the eye to the end of the tail on each side of body (vs. dorsal usually scattered with blackish-brown or black spots or blotches, a ochre-yellow, yellowish-brown, ochre-red, orange-brown or reddish-brown stripe often reduced to a succession of elongate blotches on the anterior part of the body on each side). For more detailed information and visual comparisons, please refer to Table 3 View TABLE 3 & Figure 6 View FIGURE 6 .
Hebius youjiangensis sp. nov. differs from H. deschauenseei by having 17 DSR at midbody (vs. 19), subcaudals 112 (vs. 115–141), preoculars 1 (vs. 2), temporals 1+1+2 (vs. 1+2), and a conspicuous, continuous beige stripe extending from behind the eye to the end of the tail (vs. dorsal surface with dark blotches, not producing a chequered pattern, a dorsolateral series of large, elongate blotches, yellow-ochre, rusty red or yellowish-brown, forming a discontinuous dorsolateral stripe).
Hebius youjiangensis sp. nov. differs from H. chapaensis by having 19-17-17 DSR counts (vs. 17-17-17), dorsal scales feebly keeled except the outermost rows (vs. dorsal scales weakly keeled anteriorly, strongly keeled posteriorly), preoculars 1 (vs. 2), and having a conspicuous, beige dorsolateral stripe extending from behind the eye to the end of the tail on each side (vs. pale orange blotches anteriorly and longitudinal rodlike pattern in H. chapaensis ).
Hebius youjiangensis sp. nov. differs from H. igneus by having 17 DSR at midbody (vs. 19), subcaudals 112 (vs. 115–129), preoculars 1 (vs. 2), a conspicuous, beige dorsolateral stripe extending from behind the eye to the end of the tail on each side (vs. a dorsolateral series of bright orange, coral or rusty red blotches), and the background color of the anterior venter creamish-yellow (vs. venter overall dark, i.e., dark brown, blackish-brown or black).
Hebius youjiangensis sp. nov. differs from H. annamensis by having DSR 19-17-17, feebly keeled except the outermost rows (vs. 15 or 17 dorsal scale rows at midbody, moderately keeled at midbody, strongly keeled posteriorly, usually smooth on the 1st dorsal scale row), prefrontals 2 (vs. prefrontal single), subcaudals 112 (vs. 116–146), preoculars 1 (vs. 2), and a conspicuous, beige dorsolateral stripe extending from behind the eye to the end of the tail on each side (vs. dorsal pattern made of bright orange or rusty-red blotches, usually transversally elongate as crossbars anteriorly, then becoming irregular, broken spots posteriorly).
Hebius youjiangensis sp. nov. differs from H. venningi ( Wall, 1910) by having 19 dorsal scale rows at anterior body, dorsal scales feebly keeled except the outermost rows (vs. 17 dorsal scale rows at anterior body, dorsal scales moderately keeled at midbody, strongly keeled posteriorly but 1st DSR smooth), subcaudals 112 (vs. 115–129), postoculars 2 (vs. 3), and a conspicuous, beige dorsolateral stripe extending from behind the eye to the end of the tail on each side (vs. a dorsolateral series of irregular blotches, yellow-ochre or yellowish-brown, enlarged and forming a chain on the first quarter to third of the body, progressively smaller, usually vanishing after midbody).
Hebius youjiangensis sp. nov. differs from H. nigriventer ( Wall, 1925) by having 19 DSR counts at anterior body (vs. 17), preoculars 1 (vs. 2), anterior venter creamish-yellow, with irregular black blotches in the middle and outer quarter of ventrals, the posterior part almost completely black (vs. venter entirely very dark, sometimes with two, narrow longitudinal paler stripes), and a conspicuous, beige dorsolateral stripe extending from behind the eye to the end of the tail on each side (vs. a bright orange, rusty-red or reddish-brown, rectangular blotches,, becoming smaller posteriorly and turning to an irregular stripe posteriorly on each side).
Hebius youjiangensis sp. nov. differs from H. taronensis ( Smith, 1940) by having 19-17-17 DSR counts (vs. 17-17-17), relatively longer tail length (TAL/TL ratio 0.30 vs. TAL/TL <0.29), PRO 1, PO 2 (vs. PRO 2, PO 3), and a conspicuous, beige dorsolateral stripe extending from behind the eye to the end of the tail on each side (vs. a series of small, elongate, dorsolateral blotches, pale yellowish-brown or ochre-brown on each side in H. taronensis ).
In addition, with other seven congeners that have 17 DSR at midbody. Hebius youjiangensis sp. nov. can be separated from H. arquus ( David & Vogel, 2010) , H. atemporalis ( Bourret, 1934) , H. frenatus (Dunn, 1923) , H. sarwacensis (Günther, 1872) , H. sauteri (Boulenger, 1909) , and H. maximus (Malnate, 1962) by having 19-17-17 DSR counts (vs. 17-17- 15 in H. arquus and H. frenatus , and 17-17- 17 in H. atemporalis , H. sarwacensis H. sauteri and H. maximus ), from H. groundwateri (Smith, 1922) by having divided cloacal plate (vs. CP entire), preoculars 1 (vs. 2), ventrals 3+160 (vs. 147), and subcaudals 112 (vs. 120). Furthermore, the new species differs from H. arquus by having a single loreal (vs. the absence of a loreal). It differs from H. atemporalis , H. frenatus , H. sarwacensis also by having 9 supralabials (vs. 6 in H. atemporalis , 5–8 in H. sauteri , and 8 in H. frenatus and H. sarwacensis ).
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