Fea viper
| Fea viper | ||||||||||||
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Head of fea viper ( Azemiops feae ) |
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| Scientific name | ||||||||||||
| Azemiops feae | ||||||||||||
| Boulenger , 1888 |
The fea viper ( Azemiops feae ), named after the Italian zoologist and explorer Leonardo Fea , is a species of the primeval vipers (Azemiopinae) within the vipers . The taxonomic position of this species, which is widespread in Southeast Asia, is still being discussed; the representatives of the genus Azemiops are probably the most original species within the vipers. The Fea viper is very rare, so very little is known about its way of life.
features
The Fea viper has an average length of about 80 centimeters and can reach a maximum length of about one meter. It is a smoothly scaled , relatively slender snake with an elliptical, flattened and slightly broadened head, the top of which is covered with large shields. The body is cylindrical and relatively slender with a short tail. The color of the snake is very noticeable. The upper side is mostly blue-black with narrow, widely spaced, orange-red cross bars. Some of these are only designed as alternating one-sided half-bands that do not meet in the middle of the back. The head is orange-red to whitish. The top of the head is colored black and has a yellowish central stripe. In detail, the prefrontal shields (prefrontals), frontal shields (frontals) and the last front temporal shields (temporals) are black. The median divides the head in half and extends to the fifteenth vertebra. Above the seventh and tenth vertebra, it is expanded while it tapers backwards. The eye is yellowish with a vertically aligned pupil . The ventral side is light gray with a slight pink sheen. In the middle of the body it has around 17 rows of scales, which, unlike other vipers, are not keeled. The ventral scales between 180 and 189 are rounded, 42 to 53 rows of paired subcaudalia adjoin the underside of the tail . The anal scale is undivided.
The snake's muzzle is short and wide, and slightly wider than it is long. The parietal shields are about as long as their distance from the tip of the snout. The upper lip shields ( supralabials ) lie directly on the lower eye shields ( suboculars ) instead of being separated from them by a row of scales, as is the case with all other vipers. In total, the snake has six upper lip shields and seven to eight lower lip shields ( sublabials ), two to three fore-eye shields (pre- oculars ) and one to two rear-eye shields ( post-oculars ). Below the head is a pair of short chin scales that are separated from the belly scales by three horizontal rows of small scales. Unlike all other vipers, the relatively short poison teeth in the front of the jaw have a groove from the tip of the tooth to the opening of the venom canal and a blade-like widening on the back of the tooth. The other bones of the upper jaw, the palatine and the pterygoid , are equipped with numerous small teeth.
The snake has compared to other vipers from the groups of pit vipers (Crotalinae) and the Real Vipers (Viperinae) a number of features, which are considered originally for all vipers. These features, reminiscent of snakes or poisonous snakes , are the relatively slender body and the elongated head, covered by large shields. In addition, despite the cool distribution area, it probably reproduces through eggs (this has not yet been clarified exactly). The cross-banded drawing , reminiscent of Kraits , is also unusual for vipers. On the other hand, there are features that the Fea Viper shares with other representatives of the vipers, especially the general structure of the skull and similarities in the histology of the venom glands .
Occurrence and habitat
The azemiopinae comes from central China (from western Yunnan and southern Shaanxi east to Zhejiang , south to Guangxi , Guizhou , Sichuan , Fujian , Jiangxi ) to northern Myanmar and northern Vietnam and southeast Tibet in isolated mountainous areas before. Exact information on the distribution is not available, however, as the snake could only be found very rarely. It is also unclear how far eastward the species is and in which areas parapatry between Azemiops feae and Azemiops kharini can be observed. References in this regard often relate to Azemiops feae s. lat. and it is not entirely clear where these are populations of Azemiops kharini .
Their habitat are cool and moist mountain forests from 600 to around 1,000 m in height. She prefers cooler locations with average temperatures between 20 and 25 ° C. This species is rarely found on roads or in rice fields; in Vietnam, bamboo forests with a soft layer of litter are described as habitats. For China, on the other hand, loose bush forests in the mountains are given as habitats.
Way of life
Almost nothing is known about the way of life, nutrition and reproduction of this species. The snake is nocturnal and prefers damp and cool ground with ground temperatures between 18 and 20 ° C. The activity time is from March to November, the rest of the year the animals overwinter. The animals do not dig, but it has been observed that they move earth with their snouts.
One specimen kept in captivity ate mice and a wild-caught shrew of the species Crocidura attenuata was found in the stomach. Small reptiles are also considered to be food, although in captivity all types of reptiles, amphibians and fish were rejected as food. When threatened, the body is flattened, making it wider, the halves of the lower jaw are pulled apart so that the head also becomes triangular. In some captured specimens, a vibration of the tail was also observed. If the snake is cornered, it will bite, and its fangs will not always pop out.
According to observations, the mating behavior of the Fea vipers corresponds to that of other vipers. The two mating partners first crawl parallel to each other and the male then wraps his front body around the female during mating while introducing one of the two hemipenes . The copulation takes about 10 minutes, the few known pairings were observed in early July. The viper probably lays eggs and is therefore oviparous , although the size of the clutch and the appearance of the young are unknown. This assumption comes from the finding of two females who had several ovarian follicles in their fallopian tubes . However, the examination of the fallopian tubes and the genital tract did not allow any concrete conclusion as to whether eggs were actually laid.
Taxonomy
The first description was in 1888 by George Albert Boulenger on the basis of two snakes collected by Leonardo Fea . It was not until 1935 that three specimens were added to the only two animals previously known to science. In 1985, a small number of live Fea vipers were exported from northern Myanmar (then Burma ), but they did not survive long in captivity. In their home countries, the animals are also rarely but regularly sighted.
Mainly on the basis of data from the mitochondrial DNA and the composition of the poison, the Fea viper is nowadays set as a basal taxon in the vipers (Viperidae). Other molecular biological studies, however, classify the vipers as a sister group of the pit vipers (Crotalinae), and on the basis of some morphological features such as the pupil and body shape, an assignment to the relationship of the toad vipers (Causinae) was assumed.
Finally, the systematic allocation has not yet been clarified. However, a taxon Azemiopinae was again supported in 2011 and 2016 by molecular biological studies with 5 and 11 mitochondrial and nuclear genes respectively ( Pyron et al., 2011; Alencar et al., 2016).
In 2013, Orlov and colleagues described a second species of the genus, Azemiops kharini . 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.
Poison
Like all vipers, the Fea viper is also poisonous, but there are no known cases of human poisoning. The amount of poison from five milked snakes was about 1.75 mg dry weight, with two snakes no significant amounts could be obtained. The lethal dose LD 50 in mice with a body weight of 18 to 22 grams is about 0.52 mg. The composition has not been fully elucidated; on the basis of electrophoretic studies, 22 different protein components with molar masses of 10,000 to 80,000 u could be determined. The amount of poison released in the bite is not known; it is probably well above the lethal dose for the prey.
Research by Bryan Grieg Fry shows a great similarity to the venom of Wagler's lance viper ( Tropidolaemus wagleri ). However, other studies show the closeness to the poisons of the real vipers, with the exception that the poison of the Fea-Viper has neither a blood-clotting nor a blood-cell-destroying ( haemolytic ) and the musculature-influencing ( myotoxic ) effect.
In mice, lethal doses of 0.4 to 0.6 mg of the poison cause a range of systemic symptoms. Enlargement of the blood vessels in the ears ( vasodilation ) can be detected just 10 minutes after the poison injection . After about 20 to 40 minutes, the animals become sluggish and the breathing frequency decreases, after which the animals become limp and paralysis follows , during which the animals are hardly able to stand up. Death occurs after 85 to 150 minutes; if this time is survived, the animals recover and survive. The most effective antivenins are agents against the poisons of tiger otters ( Notechis ), death otters ( Acantophis ), mambas ( Dendroapsis ) and the Central Asian cobra ( Naja oxiana ) as well as various broad spectrum antidotes.
Sources and further information
Sources cited
Much of the information in this article is taken from Mallow et al. (2003), the following sources are also cited:
- ^ A b c d 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.
- ↑ Species portrait at Gifte.de
- ^ E. Zhao: Venomous Snakes of China. in P. Gopalakrishnakone, LM Chou: Snakes of Medical Importance. Venom and Toxin Research Group, National University of Singapore, 1990; Page 247, ISBN 9971-62-217-3
- ^ KV Kardong: Observations on live Azemiops feae, Fea's Viper. Herpetological Reviews 17 (4), 1986; Pages 816 to 820. Quoted from Mallow et al. 2003
- ↑ 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.
- ↑ The Reptile Database: Genus Azemiops (listed species) (accessed July 20, 2018)
- ↑ DK Vest: Preliminary studies on the venom of the Chinese snake Azemiops feae, Boulenger (Fea's viper). Toxicon 24 (5), 1986; Pages 510 to 513. PMID 3087034
- ↑ Dr. Bryan Grieg Fry: Viper Research ( Memento from May 11, 2006 in the Internet Archive )
- ↑ D. Mebs, U. Kuch, J. Maier: Studies on venom and venom apparatus of Fea's viper, Azemiops feae. in Toxicon. 32 (19), 1994: pages 1275-1278. PMID 7846698
literature
- David Mallow, David Ludwig, Göran Nilson: True Vipers. Natural History and Toxicology of Old World Vipers . Krieger Publishing Company, Malabar, Florida 2003, ISBN 0-89464-877-2 , pp. 150-159 .
- Dieter Schmidt: Snakes - biology, species, terraristics . Bede Verlag, Ruhmannsfelden 2006, ISBN 3-89860-115-3 , p. 230 .
Web links
- Picture of the Fea-Viper at Gifte.de
- Fea Viper in the Saint Louis Zoo ( Memento from September 27, 2007 in the web archive archive.today )
- Azemiopinae on Palaeos.com
- Azemiops feae in The Reptile Database
- Azemiops feae inthe IUCN 2013 Red List of Threatened Species . Posted by: Lau, M. & Rao, D.-q., 2011. Retrieved January 6, 2014.
