Bush vipers
| Bush vipers | ||||||||||||
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Green bush viper ( Atheris squamigera ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Atheris | ||||||||||||
| Cope , 1862 |
The bush vipers ( Atheris ) are a genus of venomous snakes from the family of vipers (Viperidae) with 8 to 12 known species that are only found in Africa . These are snakes that are adapted to life in trees through the formation of a prehensile tail and a change in the scaling of the abdomen.
features
The types of bush vipers are mainly adapted to an arboricole , i.e. a way of life in the trees. Accordingly, they have a number of derived characteristics compared to the primarily ground-living viper species, such as the closely related puff adder ( Bitis ) and the sand rattle otter ( Echis ).
All bush vipers are relatively small with a maximum body length of 60 to 80 centimeters, they are also extremely slim and flattened on the sides, so they are much lighter than vipers living on the ground. The head is broad and clearly set off from the body by a narrow neck. The tail can be rolled up and is therefore suitable for gripping and holding onto branches. In terms of coloration, bush vipers can take on a wide spectrum, from brown and green tones to intense yellow or blue tones.
The top of the head is covered by many small and mostly smooth scales, larger head shields do not exist in bush vipers. The eyes have vertical pupils and are separated from the supralabials by one to three rows of scales and from the nasalia by two to three scales. The Usambara bush viper ( A. ceratophora ) has a special form of the over-eye scales ; here the scales are elongated like an eyebrow.
The dorsal scales are strongly keeled and overlap each other, the ventral scales are smaller and less keeled. Bush vipers have between 14 and 36 rows of scales around the middle of the body. The ventralia are rounded, the species have between 133 and 175 of these belly shields. This is followed by the anal plate and 38 to 67 undivided subcaudalia .
distribution and habitat
The distribution of the bush vipers is limited to Africa, with all species occurring in central Africa. The most western species are the black- green bush viper ( A. nitschei ) with occurrence in Guinea and the Atheris hirsuta from the Ivory Coast, which was only described in 2002 .
Systematics
The genus Atheris was first described by Edward Drinker Cope in 1862. He used individuals of the western bush viper ( A. chlorechis ), which were previously listed in the now defunct genus Chlorechis .
External system
Within the real vipers (Viperinae) the bush vipers with the marsh viper ( Proatheris superciliaris ) as the only species of the genus Proatheris , 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 Genus Adenorhinos combined into a monophyletic taxon Atherini . The genera Proatheris and Montatheris were at a revision of the genus Atheris due to their morphological and immunological differences of plasma - albumin to the other Atheris introduced TYPES 1996 as a new species.
The swamp viper is probably the most original species and is 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 .
Internal system
Depending on the source, the genus includes a different number of species. Until 2011, between eight and twelve species were listed. In addition, there is A. matildae , which was first described in 2011 .
According to Mallows, the species known today are the following ( Atheris matildae was added later):
- A. acuminata
- A. broadleyi
- Usambara bush viper ( A. ceratophora )
- Western bush viper ( A. chlorechis )
- Mount Kenya bush viper ( A. desaixi )
- A. hirsuta
- Large scale bush viper ( A. hispida )
- Shaba bush viper ( A. katangensis )
- A. matildae
- Black and green bush viper ( A. nitschei )
- A. rungweensis
- Green bush viper ( A. squamigera )
- Lowland bush viper ( A. subocularis )
supporting documents
Evidence cited
Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:
- ↑ a b ITIS only distinguishes 8 types, Mallow et al. list 12 types
- ↑ H.-W. Herrmann, U. Joger: Evolution of viperine snakes. In: Symp zool. Soc. London. 70, 1997, pp. 43-61.
- ↑ DG Broadley: A review of the tribe Atherini (Serpentes: Viperidea), with the descriptions of two new genera. In: African Journal of Herpetology. 45, 1996, pp. 40-48.
- ↑ Lenk, P., S. Kalayabina, M. Wink & U. Joger: Evolutionary relationships among the true vipers (Reptilia: Viperidae) inferred from mitochondrial DNA sequences. In: Molecular Phylogenetics and Evolution. 19, 2001, pp. 94-104 ( full text PDF; 139.5 kB ).
- ↑ Michele Menegon, Tim RB Davenport, Kim M. Howell: Description of a new and critically endangered species of Atheris (Serpentes: Viperidae) from the Southern Highlands of Tanzania, with an overview of the country's tree viper fauna. In: Zootaxa. 3120, 2011; Pp. 43–54 ( Abstract PDF; 19 kB ).
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. 39-58.
