Hebius vibakari (BOIE, 1826)
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Hebius vibakari
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| Higher Taxa | Colubridae (Natricinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
| Subspecies | Hebius vibakari danjoensis TORIBA 1986 Hebius vibakari vibakari (BOIE 1826) Hebius vibakari ruthveni (VAN DENBURGH 1923) |
| Common Names | E: Japanese Keelback Russian: Японский уж Chinese: 东亚腹链蛇 |
| Synonym | Tropidonotus vibakari BOIE 1826: 207 Tropidonotus vibikari [sic] — BOIE 1827: 535 Tropidonotus vibakari — DUMÉRIL, BIBRON & DUMÉRIL 1854: 595 Tropidonotus martensii HILGENDORF 1876: 30 (nom. subst.) Tropidonotus vibakari — BOULENGER 1893: 221 Natrix vibakari — STEJNEGER 1907: 266 Hebius vibakari — THOMPSON 1913: 423 Natrix vibakari nikolskii EMELIANOV 1929 Amphiesma vibakari — MALNATE 1960 Amphiesma vibakari — MALNATE 1962 Amphiesma vibakari — SZCZERBAK 2003 Amphiesma vibakari — ZHAO 2006 Hebius vibakari — GUO et al. 2014 Amphiesma vibakari — WALLACH et al. 2014: 34 Hebius vibakari — MACIAS et al. 2021 Hebius vibakari danjoensis (TORIBA 1986) Amphiesma vibakari danjoensis TORIBA 1986 Amphiesma vibakari danjoense — GORIS & MAEDA 2004: 211 Hebius vibakari ruthveni (VAN DENBURGH 1923) Natrix vibakari ruthveni VAN DENBURGH 1923 Amphiesma vibakari ruthveni — WEBB et al. 1962 Amphiesma vibakari ruthveni — ANANJEVA et al. 2006 |
| Distribution | Japan (Kyushu, Shikoku, Honshu) NE China (from Liaoning northward), Korea, Russia (Primorskiy and Khabarovskiy territories, Amurskaya Oblast) danjoensis: Japan (Oshima Island); Type locality: “under a decayed piece of wood at Kochidomari, Oshima Is.” ruthveni: “ from Quelpart Island, Pusan, Sinuiju, and Possiet Bay (on the Korean frontier) to Vladivostok and Khabarovka at the junction of the Ussuri” [SHANNON 1956], Korea; Type locality: Pusan, Korea. Type locality: Japan |
| Reproduction | oviparous |
| Types | Lectotype: RMNH RENA 1068. Paralectotypes: RMNH RENA.47305-07 (old registration number: 1068), collected by: Ph.P von Siebold, Japan Holotype: CAS 31487 [ruthveni] Holotype: OMNH (Osaka R-2098, male [danjoensis] |
| Diagnosis | Diagnosis (genus). Semi-aquatic snakes with keeled dorsal scales, hemipenes and sulci spermaticus simple; maxillary teeth in continuous series, gradually becoming larger posteriorly in the series or the last two teeth abruptly enlarged; internasals broad anteriorly, nostrils lateral; apical pits present or absent. Color pattern commonly consists of a series dark dots dorsolaterally, forming two longitudinal stripes [from Guo et al. 2014]. Thompson 1913 erected Hebius with the “salient character distinguishing it from all species of Tropidonotus being the densely spinous and undivided hemipenis, bearing two long apical papillae”. Diagnosis (vibakari): A race of Amphiesma vibakari with 62 to 82 subcaudals. In- habits Japan. (Map 1.). Geographical variation within the Japanese subspecies cannot be determined from the data at hand. Many specimens examined are labelled simply "Japan"; most of those with more precise data are from Honshu. The very limited data available suggest an increase in number of ventrals northward through the islands, correlated with a decrease in subcaudal number. Perhaps colleagues in Japan would be interested in more complete documentation of this possibility. (Malnate 1962: 258). Description: Scutellation: Rostral wider than high, narrowly visible from above. Internasals as wide as long, rarely longer; the internasorostral contact (the ratio between the contact of an internasal with the rostral and the contact of the adjacent nasal with the rostral) usually equal to one or more than one, rarely less than one. Prefontals longer than the internasals; wider than long, occasionally as wide as long; in broad contact with the supraoculars. Frontal longer than wide (length/width ratio: 1.2 to 1.8, mean 1.4, 16 specimens), slightly longer than its distance from the tip of the snout, equal in length to the interparietal suture or occasionally slightly shorter. Parietals most often longer than their combined width; usually truncate at their posterior border, occasionally terminating in an acute angle. Nasals divided, but occasionally divided below the nostril only; the nostril small, situated between the two plates. Loreal usually as long as high, length occasionally greater than the height, rarely the height is the greater dimension. (In one specimen the loreal is fused with the nasal on both sides of the head.) Preoculars single, rarely 2; postoculars 3, occasionally 2, very rarely 4. Anterior temporals single, rarely 2; posterior temporals single, often 2, occasionally 3; rarely the anterior and posterior temporals are separated by the contact of supralabials with the parietals. Supralabials 7, sometimes 8, rarely 6; the 3rd and 4th border the orbit in all specimens with 7 or 6 supralabials, except two (the 4th and 5th in one with 7, the 3rd only in one with 6), the 4th and 5th border the orbit when 8 supralabials occur; the 6th supralabial (occasionally the 5th) largest when 7 are present, the 7th largest when 8 are present, the 5th when there are supralabials. The supralabials contact the parietals in nine specimen four of these the contact is broad, filling the area normally occupied by posterior temporals (fusion of the temporals and supralabials?); the 5th and 6th supralabials contact the parietals in one specimen, the 6th and 7th in one, and the 6th only in two. Contact is narrow in five specimens and is made by the intrusion of the 7th supralabial (2 specimens, one side only) or the 6th (both sides in 2 specimens, one side only on one) between the two series of temporal plates. Infralabials 8, occasionally 9, rarely 7, very rarely 10; the first 4 border the anterior chin-shields (5 on one side only, one specimen); the 5th is the largest, rarely the 4th or 6th. Posterior chin-shields longer than the anterior pair, separated for 1/2 to their entire length by a series of small gular scales. Dorsal scales in 19-19-17 rows, the scales keeled in all rows except the outer (rarely the first two rows), the second (or third) lightly keeled; paired apical scale pits usually are present on the scales of the anterior portion of the body (occasionally throughout the body length) or they may be absent (when present the pits are readily visible with low power (4x) magnification). The number of dorsal scale rows is reduced by the loss of the 4th scale row (the 4th scale row is lost at a point between 53.9 and 65.7%o, mean 60.1%, of the head and body length on 14 males; 52.2 and 60.0%o, mean 57.9%o, on 13 females). Ventrals 142-155 (145 to 155, mean 148.9, on 38 males; 142 to 153, mean 146.9, on 44 females); anal divided; subcaudals 54-82 (58 to 82, mean 71.2, on 31 males; 54 to 78, mean 65.9, on 34 females). (Malnate 1962). Coloration: Dorsum gray-brown (reddish-brown or chocolate brown in life), somewhat darker medially. An indistinct pale stripe usually is present on the 5th to 7th (4th to 6th) scale rows, occasionally containing small light spots, particularly on the anterior portion of the body; a reticulate pattern of black occasionally is visible across the back; or the dorsum may be uniform. Head dark brown above, somewhat lighter on the snout; the top of the head occasionally is marked with obsolete black mottlings; paired, light occipital spots usually are present. Supralabials cream (yellow in life), the sutures of the anterior four have narrow, dark brown or black edges, these markings often boldest on the 4th labial; last labial separated from those anterior by a band of the dark head color which continues to the lip edge at the suture of the 6th and 7th (7th and 8th) labials. The light color of the last labial thus becomes part of a cream-colored (yellow in life), dark-edged nuchal band which extends from the corner of the mouth diagonally upward and backward over the nape, and often is continued for a short distance on the sides of the neck (on one specimen examined, the light color of the last labial is isolated as a central spot on the plate); the light nuchal band may be interrupted by dark color, forming a series of light, dark-edged spots or it may be reduced to a single, light spot at the angle of the jaw. A light streak may be present for a short distance along the midline of the nape, beginning at the posterior end of the interparietal suture. Infralabials cream, narrowly edged with dark color at the sutures or immaculate. Ventrum cream or grayish-white (light green or pale yellow in life); usually a row of chocolate or black dashes is present along the outer edges of the ventrals and subcaudals; occasionally these may be absent sub-caudally, or poorly defined or absent throughout the ventrum; in one specimen they are double, except for a short distance on the throat. Many young are as the adult with the pattern elements more pronounced, especially the light dorsolateral spots; the young may all pattern elements obscure or lacking. (Malnate 1962). Variation: Malnate 1962: 257. Diagnosis (ruthveni): [note: text may have OCR issues] A race of Amphiesma vibakari with 54 to 69 subcaudals. Inhabits Cheju-do, Korea, Manchuria, and the USSR Far Eastern Provinces. (Map 1.) Although the two subspecies of vibakari are most readily separated by the number of subcaudals, additional differences are indicated. In apparent correlation with the variation in subcaudals is an average reduction in the tail/total length ratio in the continental population. This ratio in vibakari is: 23 to 27% mean 25.6%, in 22 females; 23-29%, mean 26.8%, in 17 males; and in ruthveni: 21-28%, mean 23.0% in 16 females; 23-27%, mean 24.0%, in 9 males. A tendency toward the reduction of labials is exhibited by ruthveni. There are normally 7 supralabials in both vibakari and ruthveni. In ruthveni, 6 occurs in ten counts out of seventy-six, 13% (each side counted as one), of the counts made; in vibakari, 6 occurs only once in 98 counts (1%); also, 8 occurs only once (1%) in ruthveni but this number is recorded thirteen times in vibakari (13%). A similar tendency is found in the number of infralabials. Eight is the normal number; 7 occurs six times (8%), in the ruthveni counts but only once (1%), in the vibakari counts; and, in addition, in vibakari, 9 occurs 44 times (45%), and 10 occurs once (1%). (Figure 1). More vibakari specimens have a reduced postocular count than ruthveni specimens. Three postoculars are normally present, two occurs 34 times among 116 counts (29%), in vibakari, and in 16 of 74 counts (22%), in ruthveni. The change in the character of the temporal region between the two populations can best be expressed by the sum of the temporal scales present on each specimen (i.e., a temporal formula noted as 1 + 2 designates 3 scales on each side of the head, one anterior and two posterior, a total of 6 temporals). In ruthveni there are 8 temporals in four specimens (10%), 7 in three specimens (7%), 6 in fifteen specimens (36%), 5 in two specimens (5%) and 4 in eighteen specimens (43%). In vibakari a total of 8 temporals occurs in one specimen (2%), 7 in three specimens (5%), 6 in fourteen specimens (25%), 5 in three specimens (5%), 4 in thirty-three specimens (58%), 2 in three specimens (5%). The sum of the temporals most common to ruthveni is 4 or 6; in vibakari the sum of 4 is more common and 6 less common than in ruthveni. In addition, 8 is of common occurrence in ruthveni, only rarely present in vibakari, and 2, which does not occur in ruthveni is occasionally present in vibakari. The Japanese population (vibakari), as in ocular counts, shows a stronger tendency to reduce the number of temporal scutes. (Figure 1.) Some differentiation in pattern also is indicated. The dorsolateral light stripe usually is present in the nominate subspecies, whereas in ruthveni this pattern element rarely appears and the dorsum usually is uniformly colored. Emelianov (op. cit.) presents data that suggest a tendency toward an increase of dark pigment in the nuchal pattern in ruthveni. Five of 23 specimens studied by Emelianov have the light nuchal crescent broken into yellow spots. Among eleven specimens examined by me only three have a complete nuchal crescent; the nuchal pattern of thirteen is reduced to irregular, dark-edged light spots. The nuchal crescent is well-defined in all except five specimens among 45 vibakari. (Plate 1.) A somewhat greater length is attained by vibakari than by ruthveni. The ten largest specimens recorded for each subspecies average, respectively, 519.9 mm. and 479.6 mm. Five specimens from Cheju-do, three males and two females, are the only representatives of the population from that island examined. In most characteristics of scalation they are intermediate between ruthveni and vibakari. The reduced and broken nuchal crescent and uniform dorsal coloration, however, suggest a closer relationship with ruthveni. It is noteworthy that the number of ventrals and subcaudals (the tail is incomplete in one) are among the highest recorded for ruthveni (149 to 155, mean 153.3, ventrals and 67-68 subcaudals in two males and 68 in two females). Tail/total length ratios (0.237 to 0.271, mean 0.250) also are high. The specimen from Sakhalin Island (BM 1907.2.4.1), a male, also shows high ventral and subcaudal counts (155 and 69, respectively); other scale characters are inconclusive. Supralabial and nuchal patterns show a strong increase of dark color; both are reduced to a series of dark-edged light spots on the posterior two labials and the nape. The ventrals are marked with paired black spots at each side, except under the throat where the spots are reduced to the normal, single series along each side. Doubling of the ventral spotting has not been noted in any other specimen. The Sakhalin population is assumed to be associated with ruthveni. Additional specimens from the island would be of great interest. Pavloff (loc. cit.) reports two specimens from Imienpo, Manchuria, southeast of Harbin. His brief description notes the presence of a light vertebral stripe, a character not otherwise known for either race of vibakari. Close examination of the photograph accompanying Pavloff's report shows what appears to be a middorsal stripe, but because of the poor quality of the photograph, and its reproduction, this cannot certainly be determined. Unfortunately, Pavloff gives little data for his specimens other than pattern; they are, however, apparently representatives of ruthveni. (Malnate 1962: 258). |
| Comment | Type species: Tropidonotus vibakari BOIE 1826: 207 is the type species of the genus Hebius Thompson 1913. Key: Zhou et al. 2019 provide a key to the Hebius species of China. |
| Etymology | Habius is derived from the Japanese noun “Hebi" (which means snake in Japanese), and the -us ending indicates it is masculine (David et al. 2021). Guo et al. (2014: 438) also stated that Hebius was masculine but these authors variously treated it as neutral (for example: Hebius modestum, p. 437 & 438) or feminine (Hebius modesta, p. 428). |
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