Asp viper, Vipera aspis
Viperinae is a subfamily of terrestrial and arboreal venomous vipers (family Viperidae) characterized by a lack of the heat-sensing pit organs that characterize their sister group, the subfamily Crotalinae. Viperines are found in Europe, Asia, and Africa, and while largely tropical and subtropical, one species even occurs within the Arctic Circle. Technically known as viperines, members of Viperinae also are known by the common names of true vipers, pitless vipers, Old World vipers, or true adders. Well known members include the puff adders and bush vipers. About 66 species in 12 genera are recognized.
Because of their venom, viperines are highly feared by people. The African puff adder (Bitis arietans) has a wide distribution in Africa, is relatively common, has large size and potent venom, and exhibits a willingness to bite, all make it responsible for more fatalities than any other African snake. The saw-scaled viper (Echis carinatus) and Russell's viper (Daboia sp.), found in Asia, likewise have a powerful venom and cause a number of deaths.
Nonetheless, viperines also provide an important ecological role, helping to control populations of prey species such as rodents, scorpions, squirrels, centipedes, and so forth. They also provide food for some animals, such as birds of prey. For humans, not only do they add to the wonder of nature, but the venom offers great potential for medical use because of the specificity of the compounds on the body; some venoms, for example, are used to treat blood disorders. Viperines also have been used in Africa for a crude form of hunting, whereby a captured viperine is placed on a game trail to strike an animal using the trail.
Viperidae, the taxon to which Viperinae belongs, is a family of venomous snakes characterized by a head that is distinct from the body and by a pair of long, hollow, venom-injecting fangs that can be folded back against the top of the mouth (tip inward) when the mouth is closed. The two main subfamilies in Viperidae are Viperinae (pitless vipers or true vipers) and Crotalinae (pit vipers), although other subfamilies also are recognized. Members of the family Viperidae commonly are known as vipers. However, the term viperid also is used for members of Viperidae. Viperid offers greater specificity than the term viper since some authorities use "viper" for members of the subfamily Viperinae and "pit viper" for members of the subfamily Crotalinae (Nilson and Gutverlet 2004).
Technically, members of Viperinae may be known as viperines. However, they also are known commonly as pitless vipers, true vipers, Old World vipers (Mallow et al. 2003), and true adders (U.S. Navy 1991). Currently, 12 genera and 66 species are recognized (ITIS 2004).
Viperines differ from their sister group, the Crotalinae, by the lack of a heat-sensing pit organ, which in the pit vipers are located between the eye and the nostril on either side of the head. Members of the Viperinae subfamily range in size from Bitis schneideri, which grows to a maximum of 28 centimeters (11 inches), to Bitis gabonica, which reaches a maximum length of over 2 meters (6.5 feet).
Most species are terrestrial, but a few, such as Atheris, are completely arboreal (Mallow et al. 2003). Generally, members of this subfamily are viviparous (ovoviviparous), although a few, such as Pseudocerastes, lay eggs (Mallow et al. 2003).
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 species. This sac is an invagination of the skin between the supranasal and nasal scales and is connected to the ophthalmic branch of the trigeminal nerve. The nerve endings here resemble those in the labial pits of boas. The supernasal sac is present in the genera Daboia, Pseudocerastes, and Causus, but is especially well developed in Bitis. Experiments have shown that viperine strikes are not only guided by visual and chemical cues, but also by heat, with warmer targets being struck more frequently than colder ones (Mallow et al. 2003).
Most are tropical and subtropical, although Vipera berus occurs within the Arctic Circle (Mallow et al. 2003). Vipera berus is extremely widespread and can be found throughout most of Western Europe and all the way to Far East Asia.
|Genus||Taxon author||Species||Subsp.*||Common name||Geographic range|
|Adenorhinos||Loveridge, 1930||1||0||Uzungwe viper||Central Tanzania: Udzungwe and Ukinga Mountains.|
|Atheris||Cope, 1862||8||1||Bush vipers||Tropical subsaharan Africa, excluding southern Africa.|
|Bitis||Gray, 1842||14||2||Puff adders||Africa and the southern Arabian Peninsula.|
|Cerastes||Laurenti, 1768||3||0||Horned vipers||North Africa eastward through Arabia and Iran.|
|Daboia||Gray, 1842||1||1||Russell's viper||Pakistan, India, Sri Lanka, Bangladesh, Nepal, Myanmar, Thailand, Cambodia, China (Kwangsi and Kwantung), Taiwan and Indonesia (Endeh, Flores, east Java, Komodo, Lomblen Islands).|
|Echis||Merrem, 1820||8||6||Saw-scaled vipers||India and Sri Lanka, parts of the Middle East and Africa north of the equator.|
|Eristicophis||Alcock and Finn, 1897||1||0||McMahon's viper||The desert region of Balochistan near the Iran-Afghanistan-Pakistan border.|
|Macrovipera||Reuss, 1927||4||4||Large Palearctic vipers||Semideserts and steppes of northern Africa, the Near and Middle East, and the Milos Archipelago in the Aegean Sea.|
|Montatheris||Boulenger, 1910||1||0||Kenya mountain viper||Kenya: moorlands of the Aberdare range and Mount Kenya above 3000 meters.|
|Proatheris||Peters, 1854||1||0||Lowland viper||Floodplains from southern Tanzania (northern end of Lake Malawi) through Malawi to near Beira, central Mozambique.|
|Pseudocerastes||Boulenger, 1896||1||1||False horned viper||From the Sinai of Egypt eastward to Pakistan.|
|ViperaT||Laurenti, 1768||23||12||Palearctic vipers||Great Britain and nearly all of continental Europe across the Arctic Circle and on some islands in the Mediterranean (Elba, Montecristo, Sicily) and Aegean Sea eastward across northern Asia to Sakhalin Island and North Korea. Also found in northern Africa in Morocco, Algeria, and Tunisia.|
*) Not including the nominate subspecies.
T) Type genus.
Until relatively recently, two other genera were also included in the Viperinae. However, they were eventually considered so distinctive within the Viperidae that separate subfamilies were created for them (McDiarmid et al. 1999):
Nevertheless, these groups, together with the genera currently recognized as belonging to the Viperinae, are still often referred to collectively as the true vipers (Mallow et al. 2003).
Broadley (1996) recognized a new tribe, Atherini, for the genera Atheris, Adenorhinos, Montatheris, and Proatheris, the type genus for which is Atheris (McDiarmid et al. 1999).
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