Azemiops
| Azemiops | ||||||||||
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Fea viper ( Azemiops feae ) |
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| Systematics | ||||||||||
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| Scientific name of the subfamily | ||||||||||
| Azemiopinae | ||||||||||
| Liem , Marx & Rabb , 1971 | ||||||||||
| Scientific name of the genus | ||||||||||
| Azemiops | ||||||||||
| Boulenger , 1888 |
Azemiops is the only genus of the primeval vipers (Azemiopinae) and belongs to the family of vipers (Viperidae). In addition to the Fea viper ( Azemiops feae ), another species, Azemiops kharini , has been describedsince 2013.
features
They are medium-sized snakes that reach a size between 60 and 80 cm. Specimens longer than 90 cm are known from captivity. The head is elongated and only slightly separated from the neck. The eye has a pupil that is vertically slit when exposed to light. The basic color of the body is blue-black. There are whitish to reddish horizontal stripes that are often interrupted over the middle of the back. The ventral side is olive-gray. Azemiops kharini and Azemiops feae have choanal processes on the palate, large scales on top of the head and smooth trunk scales ( Scuta dorsalia ). The large head shields, a relatively slim build and smooth body scales are reminiscent of an adder . A connection of the prefrontals to the lateral areas of the frontals can be seen as a primitive feature of the skull and an anatomical commonality with toad vipers ( causus ) . In representatives of the real vipers, the prefrontals extend to the front edges of the frontals; the point of contact between these bones is almost on the midline of the skull.
Azemiops species have poison glands and movable fangs located in the anterior upper jaw ( solenoglyph tooth position). The fangs are relatively small.
Delimitation of the species
Azemiops kharini and Azemiops feae can be distinguished from one another by the color of the dorsal head and the anatomy of the skull. The shape of the Basisphenoids of Azemiops kharini largely corresponds to that of the front part of this bone at feae Azemiops , but is at kharini Azemiops shorter. The posterior part of the base phenoid is enlarged in Azemiops feae . The basioccipital has two tubercles anteroventral (anterior, lower side) in Azemiops feae , but not in Azemioips kharini .
Other differences include:
- Body size: Azemiops kharini is usually larger and reaches a total length of up to about 100 cm (in captivity) than Aemiops feae ,
- Number of ventral shields: 189 to 201 in Azemiops kharini , 177 to 187 in Azemiops feae ,
- Number of rows of dorsal scales: 15 to 17 in Azemiops kharini , 13 to 15 in Azemiops feae ,
- Number of trunk vertebrae: 193 to 201 vertebrae in Azemiops kharini , 170 to 181 vertebrae in Azemiops feae and
- Number of teeth: pterygoid with 14 to 15 teeth in Azemiops kharini and 10 to 12 teeth in Azemiops feae .
Anatomical dimensions / proportions (skeleton)
Orlov & Snetkov (2017) determined the following parameters through investigations on preparations from the collection of the Department of Herpetology, Zoological Institute of the Russian Academy of Sciences :
- Azemiops feae : head-trunk length (snout to anus) 484 mm, tail length 87 mm, distance between the lateral edges of the supraorbital shields * 7 mm, length of the head from the tip of the snout to the posterior end of the jaw 20 mm, eye diameter 2 mm, Distance between the nostril and the eye 2 mm.
- Azemiops kharini : head-trunk length (snout to anus) 341 mm, tail length 42 mm, distance between the lateral edges of the supraorbital shields 6 mm, length of the head from the tip of the snout to the posterior end of the jaw 17 mm, eye diameter 2 mm, distance 3 mm between the nostril and the eye.
* Scales above the eye socket
This information was determined on a few copies and is only intended as a guide.
Head drawing
Azemiops feae : The top of the head is black in color and has a yellowish central line. In detail, the prefrontal shields (prefrontals), frontal shields (frontals) and the last front temporal shields (temporals) are black. The median divides the head in exactly two halves and extends to the fifteenth vertebra. Above the seventh and tenth vertebra, it is expanded while it tapers backwards. The cheeks are marked by a narrow, dark band that extends over the last anterior temporals. A triangular shaped band leads from the anterior eye shields ( pre-oculars ) over the upper and posterior parts of the fourth and the lower half of the fifth upper lip shield ( supralabials ). The underside of the head is mottled yellow and gray. In detail, the following shields are gray: the edges of the mental, ingenious, the first lower lip shield ( sublabial ) and partly the second, third, fourth and fifth lower lip shield . Two gray stripes run over the neck and the first two ventral shields ( ventralia ). Newborn young snakes have a dark, black color on the underside of the head.
Azemiops kharini : the head is white to pink-white and has two black longitudinal stripes on top, which lead over prefrontals, frontals and parietals 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
distribution and habitat
The distribution area extends over areas in Vietnam (northeast), China (south) and Myanmar . The populated biotopes are submontane to montane ( A. feae : at an altitude of 100 to 2,200 meters) and are represented by forests, bamboo stands and the like near the water . The climatic conditions are foggy and damp to wet. The subsoil is stony and karst and can also be described as damp to wet. The temperatures in the distribution area ( Tam Đảo region , Vĩnh Phúc province , Vietnam) are estimated by Trutnau (1998) to be −5.4 to 1.4 ° C between January and the end of March and 20 to 26 ° C between May and October (at night often well below 20 ° C). Hibernation is held over the winter months.
Way of life
Little is known about the way of life as the species lead an extremely hidden way of life. Subadult specimens are mostly found during nocturnal expeditions, for example on wet fallen leaves or wet stones. According to Orlov & Snetkov (2017), reproduction takes place through oviparity (egg-laying). The clutch of Azemiops feae contains about 6 eggs , that of Azemiops kharini about 5 eggs. Various information about nutrition can be found in the literature. In some cases, lizards are also given as possible prey. It should be noted, however, that this information should be viewed with skepticism. It has been proven that small mammals such as shrews belong to the prey spectrum of Azemiops feae . In captivity, mice were accepted from Azemiops feae and specimens of Azemiops kharini also ate geckos ( Hemidactylus ).
A very humid environment seems to be essential for Azemiops species. In captivity, dry skin damage (e.g. wrinkling) and changes in behavior such as reduced activity are often seen when the relative humidity drops only slightly.
Systematics
External system
The taxonomic classification of Azemiops is considered uncertain. At times as a genus of poisonous snakes (Elapidae) and later the real vipers (Viperinae), it was transferred in 1971 by Liem , Marx & Rabb into a separate subfamily of vipers, Azemiopinae (original vipers). Similar to the toad vipers, this is regarded as a primeval and relatively basal taxon of the vipers and has morphological relationships with Viperinae and Crotalinae ( pit vipers ). Despite the lack of a pit organ , an assignment of Azemiops to Crotalinae was proposed due to some parallels . However, it can be assumed that Azemiops or Azemiopinae should be regarded as phylogenetic sister taxons of the Crotalinae. Orlov & Snetkov (2017) confirmed the assignment of Azemiops to a separate subfamily Azemiopinae on the basis of studies on skeletal morphology . Furthermore, a taxon Azemiopinae is supported by molecular biological studies with 5 or 11 mitochondrial and nuclear genes respectively ( Pyron et al., 2011; Alencar et al., 2016).
species
There are currently (status: 2018) two species of the genus Azemiops known:
- Fea viper , Azemiops feae Boulenger 1888 ( type species )
- Azemiops kharini Orlov , Ryabov & Tao 2013
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 .
Individual evidence
- ↑ a b c d e f g Snetkov & Orlov: Phylogenetic analysis of Old World Viperid Snakes (Serpentes, Viperidae) based on skeletal morphology . Russian Journal of Herpetology, pp. 22-34, vol. 24, no. 1, 2017.
- ^ A b Dieter Schmidt: Atlas snakes - species, keeping, care , bede-Verlag, Ruhmannsfelden, 2006; Nikol Verlag (2009). ISBN 978-3-86820-011-9 .
- ↑ a b Chris Mattison: Encyclopedia of Snakes , BLV Buchverlag, Munich, 2007. ISBN 978-3-8354-0360-4 .
- ↑ Azemiops kharini in The Reptile Database (accessed July 20, 2018)
- ↑ a b c IUCN Red List: Azemiops feae (accessed on July 22, 2018)
- ↑ Mark O'Shea: Poisonous snakes - All kinds of the world in their habitats , Franckh-Kosmos-Verlag, 2006. ISBN 978-3-440-10619-8 .
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.
- Orlov, Ryabov & Nguyen: On the taxonomy and the distribution of snakes of the genus Azemiops Boulenger, 1888: Description of a new Species . Russian Journal of Herpetology Vol. 20, No. 2, 2013, pp. 110-128.
- Ludwig Trutnau: Snakes in the Terrarium Vol. 2: Poisonous snakes . Verlag Ulmer, Stuttgart 1998, ISBN 3-800-1705-23 .
