Azemiops kharini
| Azemiops kharini | ||||||||||||
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| Scientific name | ||||||||||||
| Azemiops kharini | ||||||||||||
| Orlov , Ryabov & Nguyen , 2013 |
Azemiops kharini , sometimes referred to in German as the Weißkopf-Fea-Viper , is a species of snake from the family of the vipers (Viperidae) and belongsto the genus Azemiops within the monotypical subfamily of the primeval vipers (Azemiopinae). It was described in 2013and is next to the Fea viper ( A. feae ) the second known species of the genus.
features
Azemiops kharini is a medium-sized viper with a relatively slim, cylindrical body. The body is almost round in cross section. The tail is short. It reaches a total length of around 50 to 70 cm, in captivity up to 98 cm (females) or 92 cm (males). The head is elongated, flat and is moderately separated from the neck. The nostril is in a single nasal . The eye is relatively small and has a pupil that slits vertically when exposed to light.
On the skull there are 14 teeth on the pterygoid , the dental (toothed lower jawbone) has 15 to 16 teeth. The upper jaw ( maxillary ) is shortened, has movable, tubular fangs (poisonous teeth) in the front area and has no further teeth. There are 193 to 201 vertebrae in the trunk spine and 46 to 51 tail vertebrae. The holotype showed a thickening of the bone mass of the last caudal vertebrae. The authors Orlov et al. emphasized the physical integrity of the tail of this specimen and draw anatomical parallels to similar structures, such as thickened tail ends in Ankylosaurus sp. and representatives of the Glyptodontidae (extinct group of mammals).
Specimens of Azemiops kharini were identified several times in the past as Azemiops feae , since the examined specimens were not related to a type specimen. The species can be distinguished from one another by the coloring or drawing of the head, among other things.
Hardly any information is available on the composition and pharmacology of the poisonous secretion of Azemiops kharini . The venom of the closely related Fea viper is primarily neurotoxic , with polypeptides that interact with nicotine receptors .
coloring
The basic color of the body is blue-black. There are around 14 to 16 orange-colored cross bars along the body, which are often interrupted over the middle of the back. The ventral side is grayish-olive in color. The tip of the tail is yellowish. The head is white to pinkish-white. Young snakes and subadult animals have a lighter head. With increasing age, the color changes more to pink. The head has two black longitudinal stripes on the upper side, which lead over the prefrontals ( scutum praefrontale ), frontals ( scutum frontale ) and parietals ( scutum parietale ) and are connected to the blackish, dorsal body color in the neck. A black point appears in the lower corner of the lateral supraorbital shield (upper eye shield) and in the upper corner of the anterior temporal shield. Between the dark bands of the back of the head is a narrow, white stripe that widens in the neck. There is a narrow, dark stripe on each cheek. The underside of the head is yellowish, apart from the genius shields colored gray. From the first ventral shields on, a yellowish central stripe runs over the ventral shields over almost the entire first quarter of the lower front body. Newborn young snakes have a light, white underside of the head. (See also: Scale names, head shields ).
Pholidosis
The pholidosis (scaling) shows, among other things, the following characteristics:
- on top of the head large, snake-like, symmetrical shields,
- Loreale ( Scutum loreale ) present,
- Rostral is slightly wider than it is high, *
- 5 to 6 temporals * ( Scuta temporalia ),
- Eye shields ( Scuta ocularia ):
- 3 front eye shields (Scuta preocularia),
- 3 posterior shields (Scuta postocularia),
- 6 upper lip shields ( supralabials ), of which the 1st adjoin the nasal and premaxillary, the 2nd with the nasal and loreal, the 3rd with the pre-ocular, lower edge of the eye and post-ocular, the 4th with the post-ocular and temporal and the 5th and 6th with the temporal , *
- 7 lower lip shields ( sublabialia ) *,
- 4 geniuses (under head), one pair each anterior and posterior *,
- 17 rows of smooth trunk scales ( Scuta dorsalia ), less at the level of the neck (16 *) and anus (14 *),
- 189 to 201 rounded abdominal shields ( scuta ventralia ),
- 49 to 51 pairs of under- tail shields ( Scuta subcaudalia ) and
- 1 undivided anal shield ( scutum anale ).
The information marked with * refer to the holotype of Azemiops kharini .
Systematics
The first description was in 2013 by the zoologists Nikolaï Orlov , Sergei A. Ryabov & Nguyen Thien Tao under the name Azemiops kharini . Orlov et al. previously used the name Azemiops albocephala , but this is to be regarded as a synonym for Azemiops kharini . As Terra typica is Tam Đảo region (province of Vinh Phuc Province , Vietnam; origin of the type specimen in about 900 meters above sea level) specified. At the moment (as of 2018) no subspecies for Azemiops kharini are listed.
distribution and habitat
Due to rare observations, the distribution area and population density of Azemiops kharini cannot be conclusively assessed. The distribution area includes areas within Asia in Vietnam ( Vĩnh Phúc , Cao Bằng , Lạng Sơn ) and China (eastern Yunnan , Guangxi , Guizhou , eastern Sichuan , Fujian , Zhejiang , Jiangxi , Shaanxi ). The Red River in Vietnam and China appears to be a natural barrier for the known species of Azemiops . While Azemiops feae is found west of the Red River, Azemiops kharini is known east of the river. Holotype and paratypes, which were first described by Orlov et al. were used, were found at heights between 600 and 1300 meters. Specimens originally designated as Azemiops feae , which, according to more recent findings , are to be considered as Azemiops kharini , were found at heights of up to 2000 meters.
Azemiops kharini colonizes damp, foggy, wooded areas, which are often characterized by stands of bamboo or ferns , especially tree ferns . The floors are covered with rotting plant material such as fallen leaves. The subsoil is karst .
Way of life
Azemiops kharini leads an extremely hidden, nocturnal and probably largely ground-dwelling way of life. The snake is therefore rarely observed. The majority of known individuals were subadult at the time of discovery. It is possible that the species lives mostly in karst structures (crevices, hollows or the like) below the surface. The range of prey presumably includes primarily small mammals such as rodents and shrews . Lizard ( Hemidactylus sp. ) Were occasionally accepted in captivity . Animals with slow movements were observed on the surface, some of which disappeared again under leaves in the soil substrate. The night temperatures were between 18 and 20 ° C in May and early June. Young animals were observed on the surface between October and November after dark and at temperatures between 12 and 19 ° C. During such observations, light rain was repeatedly observed. There is a hibernation. The species is relatively peaceful when disturbed.
Very high humidity is necessary in captivity. A decrease in air humidity leads to changes in the appearance of the skin and a reduction in the mobility of affected animals.
Reproduction
The propagation is done by oviparity so oviparous. Before copulation , males and females crawl next to each other. The male moves with twitching body movements parallel to the female. Finally it bends its tail around the cesspool of the female, which meanwhile lifts its tail upwards. The copulation organs come together by bringing the cloacas together. Copulation takes about 10 minutes. The process can be repeated several times over a period of 10 to 12 days. The eggs are laid after about 90 days. The clutch contains about five eggs.
etymology
The specific epithet "kharini" was chosen in honor of the zoologist Vladimir Kharin , who recently died at the time of the first description . Kharin conducted numerous studies on the reptile and fish fauna in Asia.
Individual evidence
- ↑ a b c d Azemiops kharini in The Reptile Database (accessed July 20, 2018)
- ↑ University of Adelaide, Clinical Toxinology Resources: Azemiops feae (accessed July 23, 2018)
- ↑ Utkin, Weise et al .: Azemiopsin from Azemiops feae viper venom, a novel polypeptide ligand of nicotinic acetylcholine receptor. In: Journal of Biological Chemistry . Volume 287, number 32, August 2012, pp. 27079-27086, doi : 10.1074 / jbc.M112.363051 , PMID 22613724 , PMC 3411050 (free full text).
literature
The information in this article was, unless supported by individual references, in large parts of the first scientific description by Orlov et al. (2013) taken from:
- Orlov, Ryabov & Nguyen: On the taxonomy and the distribution of snakes of the genus Azemiops Boulenger, 1888: Description of a new Species. In: Russian Journal of Herpetology . Volume 20, No. 2, 2013, pp. 110-128.