Swamp viper
| Swamp viper | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the genus | ||||||||||||
| Proatheris | ||||||||||||
| Broadley , 1996 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Proatheris superciliaris | ||||||||||||
| ( Peters , 1854) |
The marsh viper ( Proatheris superciliaris , syn .: Atheris superciliaris ) is the only species of the monotypical genus of the African marsh vipers ( Proatheris ). The distribution area of this very small viper is limited to parts of the East African states of Tanzania , Malawi and Mozambique .
features
The swamp viper is on average between 40 and 50 centimeters long and reaches a maximum body length of 60 centimeters, with the females being slightly larger than the males. The body is robust, but in contrast to the puff adder it is rather elongated. The tail is relatively short and makes up about 20 percent of the total length of the males and only about 15 percent of the females. The body weight is around 70 grams for males and 100 grams for females. Young snakes are only about 15 centimeters long and weigh about 3 grams.
The snake is dark brown to gray in color with a series of 29 to 39 dark spots along the back, which have a lighter, yellowish-white line drawing on both sides of the center line, which are continued in the areas between the spots in a pair of light brown spots. There are also other smaller dark spots on the flanks. The ventral side is gray-brown with smaller spots, the subcaudals are yellow to light orange. The head has the same basic color as the body and is equipped with a characteristic dark forehead markings, a dark eye band and an equally dark tip of the snout.
The triangular and broad head is clearly set off from the body and somewhat elongated compared to other species. It is flattened on the forehead, the crown region is slightly thorny and the tip of the snout is rounded. The nostrils sit between two nasals on the side of the head. The anterior nasal scale lies against the broad rostral visible from above ; both are separated from the first shield of the upper lip ( supralabial ) by one to four rows of small scales. The eyes are medium-sized and lie on the side of the head, the distance between the mouth opening and the eye is about the diameter of the eye, the pupil is vertical and elliptical. Large head shields are missing with the exception of the long over-eye shields ( Supraocularia ), instead the head is covered with many small scales. Above the mouth opening there are eight to nine, rarely ten or eleven, upper lip shields, with the third or rarely the fourth being in contact with three to four sublabials . All scales and shields with the exception of the small scales on the top of the head are smooth, the latter have a sloping keel on the surface.
At its thickest point, the body has 27 to 29 dorsal rows of scales, which merge to 17 to 19 rows down to the area of the cloaca . The scales are very strongly keeled with the exception of the outermost. The ventral side is occupied by 131 to 159 abdominal scales ( ventralia ). The anal scale is undivided, 32 to 45 pairs of scales adjoin the underside of the tail ( subcaudalia ), whereby the last 5 pairs can be fused.
distribution and habitat
The swamp viper can be found in East Africa. In the center of the distribution area is the eastern part of the Zambezi and the Luangwa and it stretches to the coastal flatlands of Mozambique and the Shire Valley to Lake Chilwa and Lake Malawi . The southernmost sites come from central Mozambique near the city of Beira , from there the distribution area extends over the flatlands of the country to Quissanga and through Malawi to the northernmost sites in the floodplains in Tanzania at the northern end of Lake Malawi. The first description of the type performed on a specimen from Mozambique, as Terra typica is Terra Querimba , the mainland opposite the Ilha Querimba specified.
The species is only found in areas with moist to wet soil, primarily in flat swamps, floodplains and in grasslands and pastures. They are dependent on the distribution of their prey, whose buildings they usually choose as roosts. The animals are often found on pastures that have been made usable by the local population through slash and burn . On the other hand, the snakes are not found on sandy and dry soils.
Systematics and research history
The swamp viper was first scientifically described by Wilhelm Peters in 1854 and assigned to the then only viper genus Vipera . In 1961 an association with the benthic Puffottern in the genus Bitis 1965 due to various features and skull of a partially formed as a gripping tail rear end in the bush or tree vipers ( Atheris ). In a revision of the genus Atheris the snake was due to their morphological and immunological differences of plasma - albumin to the other Atheris TYPES the only kind in today's genre Proatheris filed, together with the equally monotypic genus Montatheris was introduced by Donald G. Broadly .
Among the real vipers (Viperinae), the swamp viper with the bush vipers ( Atheris ), the East African mountain otter ( Montatheris hindii ) as the only species of the genus Montatheris and the Uzungwe viper ( Adenorhinos barbouri ) as the only species of the genus Adenorhinos become a monophyletic taxon Atherini summarized. The swamp viper is probably the most original species, the sister species of all other Atherini, the exact phylogenetic position of the East African mountain otter is unknown and the Uzungwe viper is, according to the DNA findings of Lenk et al. 2001 despite morphological differences the sister species of the Usambara bush viper ( Atheris ceratophora ) within the bush vipers. The bush vipers do not represent a natural taxon in relation to this Uzungwe viper, which was spun off in 1965; the snake will accordingly be re- classified in the atheris if it is revised again .
Poison
Very little is known about the venom of the swamp viper. A composition analysis has not yet been carried out and there are few case studies . In one of the cases, a 24-year-old man was bitten on the index finger by a young snake born in a terrarium, about 20 centimeters long, with only one poison tooth penetrating the finger. As a result, there was severe pain and a clear blue-black bulla at the bite site. This regressed after about eight days and left no visible wound. A second case was much more serious and also showed the hemolytic effects typical of tree vipers , which led to a failure of the liver and kidney function. The patient survived due to an initiated plasmapheresis .
etymology
The species name superciliaris is derived from the very large and conspicuous over-eye shields ( Supraocularia ) of the snake. Super- is the Latin prefix for “over-” and cilium for “ eyelid ”. The genus name is made up of the name of the genus Atheris and the Latin prefix pro , which means "pre-Atheris" and refers to the potential position of the snake in the family tree at the base of the tree vipers.
swell
Sources cited
Most of the information in this article has been taken from the sources given under literature; the following sources are also used and cited:
- ↑ H.-W. Herrmann, U. Joger: Evolution of viperine snakes. Symp zool. Soc. London 70, 1997; Pages 43-61
- ↑ Proatheris superciliaris in the Integrated Taxonomic Information System (ITIS)
- ↑ DG Broadley: A review of the tribe Atherini (Serpentes: Viperidea), with the descriptions of two new genera. in the African Journal of Herpetology 45, 1996; Pages 40-48
- ↑ Lenk, P., S. Kalayabina, M. Wink & U. Joger (2001) Evolutionary relationships among the true vipers (Reptilia: Viperidae) inferred from mitochondrial DNA sequences. Molecular Phylogenetics and Evolution 19: 94-104. ( Full text PDF )
- ^ R. Els: Atheris superciliaris envenomation. Journal of the Herpetological Association Africa 34, 1988; according to Mallow et al. 2003
- ↑ Venom in The World of Atheris ( Memento June 7, 2008 in the Internet Archive )
literature
- David Mallow, David Ludwig, Göran Nilson: True Vipers. Natural History and Toxinology of Old World Vipers. Krieger Publishing Company Malabar, Florida, 2003; Pages 193-204. ISBN 0-89464-877-2
Web links
- The World of Atheris ( Memento June 7, 2008 in the Internet Archive )
- Proatheris superciliaris in The Reptile Database