Viperinae

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The Viperinae is a subfamily of venomous snakes commonly known as true vipers, although the term viperines is more specific and distinguishes them from the larger viperid family. This group currently consists of 12 genera and 77 species. They are found almost everywhere in the Old World where snakes occur, except Madagascar, which is why they are sometimes called the Old World vipers. Viperines lack of the heat-sensing pit organs that characterize the Crotalinae, or pit vipers. From this reason they are often referred to as the pitless vipers.

Contents

1 Description
2 Genera
3 Closely related groups
4 Notes
5 References
6 External links
7 See also

Description

Like the viperids, all true vipers have a pair of relatively long, solenoglyphous (hollow) fangs used to inject venom that is mostly proteotoxic. The head has an obvious triangular shape and eyes have elliptical (slit-shaped) pupils. For more information, see Viperidae.

Viperines range in size from Bitis schneideri, that grows to a maximum of 28 cm, to Bitis gabonica that reaches a maximum length of over 2 m. Most species are terrestrial, but a few like Atheris are completely arboreal. Generally they are ovoviviparous (e.g. Bitis, Atheris, most Echis, most Vipera), although a few are oviparous (e.g. Eristicophis and Pseudocerastes). While many species are tropical and subtropical, Vipera berus can even be found within the Arctic Circle.

Although the heat-sensing pits that characterize the Crotalinae are clearly lacking in the viperines, a supernasal sac with sensory function has been described in a number of speciesLynn W.G. The structure and function of the facial pit of the pit vipers. 1931. American Journal of Anatomy 49:97.. This sac is an invagination of the skin between the supranasal and nasal scales and is connected to the opthalmic branch of the trigeminal nerve. The nerve endings here resemble those in the labial pits of boas. The supernasal sac is present in Pseudocerastes and Causus, but is especially well developed in Bitis. Experiments have shown that strikes are not only guided by visual and chemical cues, but also by heat, with warmer targets being struck more frequently than colder onesBreidenbach C.H. Thermal cues influence strikes in pitless vipers. 1990. Journal of Herpetology 4:448-50..

Genera

Genus	Authority	Species	Subsp.*	Common name	Geographic range
Adenorhinos	Loveridge, 1930	1	0	Uzungwe viper	Southwestern Tanzania
Atheris	Cope, 1862	12	1	Bush vipers	Equatorial Africa, Nigeria, Ivory Coast
Bitis	Gray, 1842	16	3	Puff adders	Africa, southern Arabian Peninsula
Cerastes	Laurenti, 1768	3	4	Desert vipers	Central Africa, North Africa, Middle East
Daboia	Gray, 1842	1	1	Russell's viper	India, Sri Lanka, Myanmar, Thailand, Malaysia, Indonesia, Southern China, Taiwan
Echis	Merrem, 1820	8	8	Saw-scaled vipers	Africa, Middle East, Pakistan, India, Sri Lanka
Eristicophis	Alcock and Finn, 1897	1	0	McMahon's viper	Iran, Afghanistan, west Pakistan
Macrovipera	Reuss, 1927	4	5	Large Palearctic vipers	Mediterranean region, Middle East, Afghanistan, Pakistan, Tajikistan, Turkmenistan
Montatheris	Boulenger, 1910	1	0	Montane viper	Kenya
Proatheris	Peters, 1854	1	0	Lowland viper	Tanzania, Malawi, Mozambique
Pseudocerastes	Boulenger, 1896	2	0	Horned vipers	Middle East, west Pakistan
Vipera	Laurenti, 1768	23	13	Palearctic vipers	Western Europe to north-east Asia

*) Not including the nominotype (typical form).

Closely related groups

Besides the Viperinae, there are three other viperid subfamilies:

The Azemiopinae, represented by a single species, the Fea's viper (Azemiops feae).
The Causinae, or night adders.
The Crotalinae, or pit vipers.

The first three of the subfamilies, the Viperinae, Azemiopinae and Causinae, have traditionally been referred to as the true vipers and were, until relatively recently, all included in the Viperinae.

Notes

References

Mehrtens, John M. Living Snakes of the World in Color. New York: Sterling Publishing, 1987. ISBN 080696460X.
McDiarmid, Roy W., Jonathan A. Campbell, and T'Shaka A. Touré. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. 1999. The Herpetologists' League, Washington, D.C. xi + 511. ISBN 1893777014.
Mallow, David, David Ludwig, Göran Nilson. True Vipers. 2003. Krieger Publishing Company. ISBN 0894648772.

External links

EMBL Reptile Database - [Family Viperidae]
Plumed-Serpent - [Desert Scour - The Sand Viper Page]