Japanese Keelback

biology_ecology

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).

Taxonomic re-evaluation of the subspecies of Hebius vibakari (Boie, 1826) (Reptilia: Serpentes: Natricidae), with new evidence from central and northern China

description

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 1 st – 2 nd 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;

Taxonomic re-evaluation of the subspecies of Hebius vibakari (Boie, 1826) (Reptilia: Serpentes: Natricidae), with new evidence from central and northern China

diagnosis

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. 9

Taxonomic re-evaluation of the subspecies of Hebius vibakari (Boie, 1826) (Reptilia: Serpentes: Natricidae), with new evidence from central and northern China

diagnosis

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 1 st – 2 nd 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, 5 th 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.

Taxonomic re-evaluation of the subspecies of Hebius vibakari (Boie, 1826) (Reptilia: Serpentes: Natricidae), with new evidence from central and northern China