Hebius vibakari ( Boie, 1826 )

Gao, Zong-Yuan, Huang, Jun-Jie, Ding, Li, Jiang, Ke, Mao, Jie & Ren, Jin-Long, 2024, Taxonomic re-evaluation of the subspecies of Hebius vibakari (Boie, 1826) (Reptilia: Serpentes: Natricidae), with new evidence from central and northern China, Zootaxa 5474 (5), pp. 503-521 : 511-518

Hebius vibakari ( Boie, 1826)

Tropidonotus vibakari H. Boie, 1826 , Isis von Oken, 18: 207–208. Type locality: “ Decima , Japan ” [= Dejima Is., previously in Nagasaki harbor, now part of Nagasaki, Japan, 32°45’N, 129°52’E, elevation 10 m]

Tropidonotus vibikari [sic]: F. Boie, 1827, Isis von Oken, 20 (10): 535.

Tropidonotus martensii : F. Hilgendorf, 1876, Die japanischen Schlangen. Mitth. Deutsch. Ges. Ost-Asiens, 1 (10): 30.

Natrix vibakari: L. Stejneger, 1907 , Bulletin of the United States National Museum, No. 58: 266.

Hebius vibakari : J. C. Thompson, 1913, Proceedings of the Zoological Society of London, 1913 (2): 424.

Natrix vibakari ruthveni J. Van Denburgh, 1923 , Proceedings of the Academy of Natural Sciences of Philadelphia, San Francisco, ser. 4, 13: 3. Type locality: “Fusan, Kjong-Sang-Do Province, Korea ” [Pusan, Korea]

Natrix vibakari nikolskii Emelianov, 1929 , Snakes of the Far Eastern District , 3 (1): 25. Type locality: “Материк АЗии” [Ussuri Krai, Russia]

Amphiesma vibakari : E. V. Malnate, 1960, Proceedings of the Academy of Natural Sciences of Philadelphia, 112: 51.

Amphiesma vibakari danjoensis Toriba, 1986 , Japanese Journal of Herpetology, 11 (3): 126. Type locality: “Oshima Island” [ Danjo , Japan]

Hebius vibakari : P. Guo, Q. Liu, L. Zhang, J. X. Li, Y. Y. Huang, & R. A. Pyron, 2014, Zootaxa, 3873 (4): 425.

Type. Lectotype, RMNH 1068 , a 394–400 mm specimen (P.F.B. von Siebold, 1823–1826).

Type locality. “Decima, Japan ” [= Dejima Island, previously in Nagasaki harbor, now part of Nagasaki, Japan, 32°45’N, 129°52’E, elevation 10 m] (possibly in error fide Siebold in Temminck & Schlegel, 1838: iii) via lectotype selection.

Referred specimens. Specimens of H. vibakari were examined in this study:— China (N = 33). Jilin Province: CIB 8801 , CIB 8802 , CIB 8799 , CIB 8798 , CIB 8797 , CIB 78165 , CIB 78256 , CIB 78212 , CIB 78216 , CIB 78208 , CIB 78230 , CIB 78232 , CIB 78188 , CIB 78193 , CIB 78183 , CIB 78194 , CIB 78174 , CIB 78238 , CIB 78207 , CIB 78211 , CIB 78177 , CIB 78176 , CIB 78251 , CIB 78169 , CIB 78225 , CIB 78217 , CIB 78224 , CIB 78178 , Panshi City; Liaoning Province: CIB 8804 , CIB 8803 , Wulongbei County; Shanxi Province: DL 2014 ( Fig. 4 ) , Lishan National Nature Reserve; Henan Province: DL-R432 ( Fig. 5 ) , Nanyang City; DL-R433 , Pingdingshan City; Anhui Province: AHULJ 210822 , Hefei City. Specimens of published literature:— Russia (N = 2). Chabarowka: Detailed voucher unknown.— Korea (N =?). Detailed voucher unknown.— Japan (N = 14+). Regions except Hokkaido: USNM 11327 , USNM 11328 , USNM 11329 , USNM 11330 , USNM 11331 , USNM; Tokyo: USNM 36543 , USNM 36545 , USNM 36546 ; Danjo islands: NSMT H–00549 , OMNH R –2097 , OMNH R –2098 , NU –A, NU –B ( NU –A and NU –B are not explicitly numbered and are referred to by this specimen number in the original text).

Diagnosis. Hebius vibakari can be distinguished from its congeners by a combination of the following characters: (1) TaL/TL 0.202 –0.330; (2) DSR 19-19-17, outer 1st–2nd dorsal scales usually smooth, remaining dorsal scales weakly keeled or moderate keeled; (3) ventrals 127–155; (4) cloacal plate and subcaudals divided; (5) subcaudals 54–89; (6) supralabials 7, sometimes 8, rarely 6; (7) infralabials 8, occasionally 9, rarely 7, very rarely 10 and 6, 5th the largest; (8) maxillary teeth 21–22, last two or three distinctly enlarged, separated from anterior teeth by small diastema; (9) dorsum reddish-brown or chocolate brown in life, somewhat darker medially; (10) supralabials cream in life, sutures of anterior four have narrow, dark brown or black edges.

Description. Body size small to medium; head and neck are relatively distinct; TL 367–554 mm, TaL/TL 0.202 –0.330. Eye large, pupil round.

Dentition. Maxillary teeth 21–22, gradually enlarged posteriorly, last two or three distinctly enlarged, separated from anterior teeth by small diastema.

Body scalation. Dorsal scale rows 19-19-17, outer 1st–2nd dorsal scales usually smooth, remaining dorsal scales weakly keeled or moderate keeled; ventrals 127–155, ventrals of subspecies H. v. vibakari : 142–155, ventrals of subspecies H. v. danjoensis : 127–134; subcaudals 54–89, paired, subcaudals of subspecies H. v. vibakari : 54–82 (68 ± 14), subcaudals of subspecies H. v. danjoensis : 88–89 (88.5 ± 0.5) ( Table 4 ).

Head scalation. Rostral trapezoidal, wider than high; internasals scalloped annular or trapezoidal, posterior side longer; prefrontals pentagonal, bordering nasals, loreal, preocular, and supraocular; frontal hexagonal, longer than wide, gradually narrowing posteriorly, embedded into parietals at its posterior end; supraocular single on each side, subtriangular, 2.2 times longer than wide; parietals paired, elongate and broad, 1.7 times longer than frontal; nasals irregularly pentagonal or rectangular, divided into two parts to encircle round nostril in the center; loreal 1/1, small, rectangular, in contact with supralabials 2–3; preocular single, higher than wide, occasionally divided into two; postoculars 3/3, occasionally 2, 4, more rarely 1, decreasing in size downwards; supralabials 6–8, usually 7, 3rd– 4th entering orbit, and less frequent 3rd separate in contact with orbit, penultimate one usually largest; temporals 0–1+1–2+1–3; infralabials 5–10, usually 8, 5th largest; chin shields paired, second pair divergent posteriorly ( Table 4 ).

Coloration. Dorsum reddish-brown or chocolate brown in life, somewhat darker medially. Inconspicuous reddish-brown bands on outer 4th to 6th dorsal scale rows. Abdomen creamy yellow, ventral scales with ventral chains bordered by reddish brown on the outside. Supralabials cream in life, sutures of anterior four have narrow, dark brown or black edges. The mouth corner often has a light-colored oval spot, followed by a long or short light-colored short lines, some curved toward the back of the neck, left and right almost meet ( Fig. 4–7 ).

Hemipenis. The description of the hemipenis in everted condition based on the left sides of two specimens from Panshi, Jilin, China, CIB 78208 and CIB 78224 ( Fig. 8 ). Organ thin and short, hemipenial total length ( HTL) 8.9– 10.4 mm, hemipenial total width ( HTW) 2.9–3.1 mm. HTL / HTW 3.1 – 3.4 ; Y-shaped, shallowly bilobed, hemipenial truncus length ( HCL): 7.1–8.5 mm, HCL / HTL 0.79–0.82. Both sulcate and asulcate surfaces densely ornamented with spines and spinules; a large basal hook present at proximal part of truncus, which at least twice higher than adjacent spines. 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. In situ, origin of m. retractor penis magnus extends up to SC 21–25 ( Fig. 8 ).

Distribution. This species occurs in central, northern, and northeastern China (Provinces of Henan, Shanxi, Anhui, Jiangxi, Heilongjiang, Jilin, and Liaoning), South Korea (Daegu, Gangwon-do, Gyeongsangnam-do, Jejusi), mainland Japan (except Hokkaido Island) and east Russia (Chabarowsk, Primorsky Krai) ( Boie, 1826; Schlegel 1837; Duméril 1854; Boulenger, 1890; Wall et al. 1903; Barbour, 1909; Shannon, 1956; Malnate, 1962; Zhao 2006; Zhang et al. 2023) ( Fig. 2 ).

Etymology. The genus name Hebius is a masculine noun that is derived from the Japanese word “Hebi” which signifies “snake” in that language ( Thompson, 1913; David et al. 2021). The specific epithet vibakari in Japanese is fibakari, which is a famous snake in Japan. “Fi” means “sun” or “during the day”, and “bakari” means “only”. The Japanese used to think it was highly venomous, its victim will only live for one day, hence the name ( Siebold et al. 1837; Stejneger, 1907). The English name is Japanese Keelback Snake and the Chinese formal name as “dōng yà fù liàn shé” (东亚gṵḙ). The subspecies name danjoensis is based on the type locality of this subspecies, Danjo Islands ( Toriba, 1986).

Comparison. The following combination of characters sets H. vibakari apart from all other known species of the genus Hebius :

Hebius vibakari differs from H. annamensis , H. arquus , H. atemporalis , H. chapaensis , H. frenatus , H. maximus , H. nigriventer , H. sarasinorum , H. sarawacensis , H. sauteri , H. taronensis , and H. venningi by having 19 dorsal scale rows at midbody (vs. 15 or 17).

Hebius vibakari having 127–155 ventrals, it can be distinguished from H. andreae (vs. 179), H. bitaeniatus (vs. 153–177), H. clerki (vs. 162–173), H. deschauenseei (vs. 149–168), H. igneus (vs. 159–169), H. johannis (vs. 156–179), H. leucomystax (vs. 154–166), H. metusia (vs. 159–164), H. nicobariensis (vs. 162), H. optatus (vs. 156–169), H. parallelus (vs. 160–173), H. sangzhiensis (vs. 160–164) H. septemlineatus (vs. 164–175), H. terrakarenorum (vs. 159–171), H. viperinus (vs. 101), H. weixiensis (vs. 171–182), H. yanbianensis (vs. 172), and H. jingdongensis (vs.163–166).

Hebius vibakari having 54–89 subcaudals can be distinguished from Hebius boulengeri (vs. 93–113), H. celebicus (vs. 48), H. flavifrons (vs. 87–102), H. groundwateri (vs. 120–134), H. inas (vs. 93–109), H. khasiensis (vs. 87–111), H. miyajimae (vs. 87–92), H. modestus (vs. 104–122), H. sanguineus (vs. 98–104), and H. youjiangensis (vs. 112).

Hebius vibakari , with inconspicuous reddish-brown bands on the 4th to 6th dorsal scales, is distinguished from H. beddomei (vs. a series of small, short, transverse streaks of orange-colour along each side of the back), H. lacrima (vs. pale crossbars on dorsolateral stripes and a large, white nuchal blotch), H. octolineatus (vs. four dorsal stripes on each side), H. petersii (vs. a lateral series of black spots), H. popei (vs. light crossbars on dorsolateral stripes and a large white nuchal blotch) ( Günther 1864; Malnate, 1962; Purkayastha and David, 2019; Zhou et al. 2019; Hou et al. 2021).

Hebius vibakari can be distinguished from species that occur in Japan by the following characteristics: (1) fewer ventral scales (127–155) than H. concelarus (vs. 157–169), H. ishigakiensis (vs. 164–178), H. pryeri (vs. 166–183); (2) fewer subcaudals scales (54–89) than H. concelarus (vs. 94–102), H. ishigakiensis (vs. 93–109), H. pryeri (vs. 112–130).

Hebius vibakari differs from H. craspedogaster by: (1) supralabials scales usually 7 vs. usually 8; (2) infralabials scales usually 8 vs. usually 10; (3) dorsum reddish-brown or chocolate brown vs. dorsum gray or gray-brown, somewhat lighter on the vertebral region; (4) inconspicuous reddish-brown bands on the 4th to 6th dorsal scales rows vs. a string of tiny, white specks with black edges can be found within the pale stripe.

Biology. Hebius vibakari inhabits ponds and riverine surroundings in forested areas, where its diet consists of fish, amphibians, amphibian larvae, and worms. This species is also found in densely populated cities, urban fringes, and villages ( Maslova et al. 2018; Macias et al. 2021). Characterized by their small to medium size snakes, these are non-venomous, docile, and agile. Reproduction is oviparous, with the species laying two to five milky white eggs from late June to early August, with an incubation period of approximately 40 days ( Schlegel 1837; Zhao 2006). In July, a specimen was found in Hondo, Japan, carrying five eggs ( Wall et al. 1905).

Remarks. Emelianov (1929) proposed the subspecies H. v. nikolskii based on 23 specimens from Ussuri Krai, eastern Russia, differing from H. v. vibakari in number of ventrals (143–151 vs. 137–151) and subcaudals (51–64 vs. 62–83). However, this proposal overlooked the description of H. v. ruthveni by Van Denburgh (1923), leading to its reclassification as a synonym. Based on the present study, H. v. ruthveni is morphologically indistinguishable from H. v. vibakari , thereby supporting its synonymization as H. v. vibakari .

Figures

FIGURE 2. Distribution of Hebius vibakari based on museum collections, previous studies, and this study. Each shape containing the number 1 is the type locality of the subspecies.

FIGURE 4. Preserved specimen of Hebius vibakari, DL 2014, adult female, Lishan National Nature Reserve, Shanxi, China. Scale bar = 5 mm. Photographs by Zong‐Yuan Gao.

FIGURE 5. Preserved specimen of Hebius vibakari, DL-R432, adult female, Nanyang City, Henan, China. Scale bar = 5 mm. Photographs by Zong‐Yuan Gao.

FIGURE 6. Comparison of the lateral head (top), lateral (middle) and ventral (bottom) sides of the body of Hebius vibakari from different distribution sites (A. DL-R432, Nanyang City, Henan, China; B. DL 2014, Lishan National Nature Reserve, Shanxi, China; C. CIB 8804, Wulongbei town, Liaoning, China). Scale bar = 5 mm. Photographs by Zong‐Yuan Gao.

FIGURE 7. New records for two H. vibakari from northern and central China. A–B. showing color in life, adult female, from Lishan National Nature Reserve, Shanxi, China. (A) DL 2014 dorsolateral view; (B) DL 2014 ventral view. C–D. Habitat photo of DL-R432 dead in the wild from Nanyang City, Henan, China. (C) DL-R432 dorsolateral view; (D) DL-R432 ventral view. Photographs by Li Ding (A–B) and Jin-Long Ren (C–D).

FIGURE 8. The everted hemipenis of Hebius vibakari, CIB 78224, Panshi, Jilin, China, from left to right: sulcate, asulcate, and apical sides of the hemipenis. Scale bar = 5 mm. Photographs by Jun‐Jie Huang.