Bitis

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Bitis
Bitis arietans.jpg
Bitis arietans
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Subfamily: Viperinae
Genus: Bitis
Gray, 1842
Bitis distribution map.png
Synonyms [1]

Bitis is a genus of venomous vipers found in Africa and the southern Arabian Peninsula. [1] It includes the largest and the smallest vipers in the world. Members are known for their characteristic threat displays that involve inflating and deflating their bodies while hissing and puffing loudly. [2] The type species for this genus is B. arietans , [1] which is also the most widely distributed viper in Africa. [3] Currently, 18 species are recognized. [4]

Contents

Members of the genus are commonly known as African adders, [2] African vipers, [3] or puff adders.

Description

Size variation within this genus is extreme, ranging from the very small B. schneideri , which grows to a maximum of 28 cm (11 in) and is perhaps the world's smallest viperid, to the very large B. gabonica , which can attain a length over 2 m (6.6 ft) and is the heaviest viper in the world. [2]

All have a wide, triangular head with a rounded snout, distinct from the neck, and covered in small, keeled, imbricated scales. The canthus is also distinct. A number of species have enlarged rostral or supraorbital scales that resemble horns. Their eyes are relatively small. They have large nostrils that are directed outwards and/or upwards. Up to six rows of small scales separate the rostral and nasal scales. All species have a well-developed supranasal sac. The fronts of the maxillary bones are very short, supporting only one pair of recurved fangs. [2] [5]

These snakes are moderately to extremely stout. Their bodies are covered with keeled scales that are imbricated (overlapping) with apical pits. At midbody, the dorsal scales number 21–46. Laterally, the dorsal scales may be slightly oblique. The ventral scales, which number 112–153, are large, rounded, and sometimes have slight lateral keels. Their tails are short. The anal scale is single. The paired subcaudal scales number 16-37 and are sometimes keeled laterally. [2] [5]

Geographic range

Puff adders are found in Africa and the southern Arabian Peninsula. [1]

Behavior

Bitis species are known for their behavior of inflating and deflating their bodies in loud hissing or puffing threat displays. They are terrestrial ambush predators, and appear sluggish, but can strike with amazing speed. [2] In contrast to the pitvipers of the subfamily Crotalinae, Bitis species appear to lack heat-sensitive organs and showed no differences in their behavior in laboratory tests towards warm and cool objects that mimicked prey. [6] [7]

The rectilinear locomotion is very common in many Bitis species.

Reproduction

All members are viviparous and some give birth to large numbers of offspring. [2]

Venom

All members of this genus are dangerous – some extremely so. [2] At least six different polyvalent antivenoms are available. Five are produced by Aventis Pasteur (France), Pasteur Merieux (France) and SAIMR (South Africa). All of these specifically protect against B. arietans and four also cover B. gabonica . [8] [9] At least one protects specifically against bites from B. nasicornis : India Antiserum Africa Polyvalent. [10] In the past, such antivenoms have been used to treat bites from other Bitis species, but with mixed results. [2]

Species

ImageSpecies [1] Taxon author [1] Subsp.* [4] Common nameGeographic range [1]
B. albanica Hewitt, 19370Albany adderRepublic of South Africa, Eastern Cape Province from Port Elizabeth to near Committees.
Kopf einer Puffotter.JPG B. arietans T(Merrem, 1820)1Puff adderMost of sub-Saharan Africa south to the Cape of Good Hope, including southern Morocco, Mauritania, Senegal, Mali, southern Algeria, Guinea, Sierra Leone, Ivory Coast, Ghana, Togo, Benin, Niger, Nigeria, Chad, Sudan, Cameroon, Central African Republic, northern, eastern and southern Democratic Republic of the Congo, Uganda, Kenya, Somalia, Rwanda, Burundi, Tanzania, Angola, Zambia, Malawi, Mozambique, Zimbabwe, Botswana, Namibia, South Africa, also occurs on the Arabian peninsula, where it is found in southwestern Saudi Arabia and Yemen
Bitis armata 46045953.jpg B. armata (A. Smith, 1826)0Southern adderRepublic of South Africa, Southwestern Western Cape, from West Coast National Park to De Hoop Nature Reserve
Bitis atropos00.jpg B. atropos (Linnaeus, 1758)0Berg adderIsolated populations in the mountainous areas of southern Africa: the Inyanga Highlands and Chimanimani Mountains of eastern Zimbabwe and nearby Mozambique, in South Africa along the Drakensberg Escarpments in the provinces of Transvaal, western Natal, Lesotho and eastern Free State, and in the southern coastal mountains of western and eastern Cape Province
Bitis caudalis00a.jpg B. caudalis (A. Smith, 1839)0Horned adderThe arid region of southwest Africa: southwest Angola, Namibia, across the Kalahari Desert of southern Botswana, into northern Transvaal and southwestern Zimbabwe, in South Africa from the northern Cape Province south to the Great Karoo
Bitis cornuta 15131892.jpg B. cornuta (Daudin, 1803)0Many-horned adderThe coastal region of southwest Namibia through west and southwest Cape Province in South Africa, with a few isolated populations in eastern Cape Province
Bitis gabonica.jpg B. gabonica (A.M.C. Duméril, Bibron & A.H.A. Duméril, 1854)0Gaboon viperGuinea, Ghana, Togo, Nigeria, Cameroon, DR Congo, Central African Republic, southern Sudan, Uganda, Kenya, eastern Tanzania, Zambia, Malawi, eastern Zimbabwe, Mozambique, northeast KwaZulu-Natal Province in South Africa
B. harenna Gower, Wade, Spawls, Böhme, Buechley, Sykes, & Colston, 20160Bale Mountains adderEthiopia
B. heraldica (Bocage, 1889)0Angolan adderThe high plateau of central Angola
Bitis inornata.jpg B. inornata (A. Smith, 1838)0Plain mountain adderIsolated population on the Sneeuberge, eastern Cape Province, South Africa
Viperidae - Bitis nasicornis.JPG B. nasicornis (Shaw, 1792)0Rhinoceros viperFrom Guinea to Ghana in West Africa, and in Central Africa in the Central African Republic, southern Sudan, Cameroon, Gabon, Congo, DR Congo, Angola, Rwanda, Uganda and western Kenya
Viperidae - Bitis parviocula.JPG B. parviocula Böhme, 19770Ethiopian mountain adderKnown from only five localities in the highlands to southwest Ethiopia, at altitudes of 1700–2800 m. [11]
Namibian Sidewinder Bitis peringueyi.jpg B. peringueyi (Boulenger, 1888)0Peringuey's desert adderThe Namib Desert from southern Angola to Lüderitz, Namibia
Bitis gabonica-- the Gaboon Viper (22009086901).jpg B. rhinoceros (Schlegel, 1855)0West African Gaboon viperGuinea, Guinea-Bissau, Liberia, Sierra Leone, Ivory Coast, Ghana, Togo
Bitis rubida 15741585.jpg B. rubida Branch, 19970Red adderSeveral isolated populations in the northern Cape Fold Mountains and inland escarpment in Western Cape Province, South Africa
Bitis schneideri 87936651.jpg B. schneideri (Boettger, 1886)0Namaqua dwarf adderWhite coastal sand dunes from Namibia, near Lüderitz, south to Hondeklip Bay, Little Namaqualand, South Africa
Bitis worthingtoni.jpg B. worthingtoni Parker, 19320Kenya horned viperRestricted to Kenya's high central Rift Valley at altitudes over 1500 m
Bitis xeropaga 15273955.jpg B. xeropaga Haacke, 19750Desert mountain adderNorthwestern Cape Province in South Africa and the arid mountains of the lower Orange River basin, north into southern Namibia and Great Namaqualand as far as Aus

*) Not including the nominate subspecies.
T) Type species.

Taxonomy

Lenk et al. (1999) used molecular data (immunological distances and mitochondrial DNA sequences) to estimate the phylogenetic relationships among species of Bitis. They identified four major monophyletic groups for which they created four subgenera: [2]

For now, this division is of little consequence as far as the nomenclature is concerned. However, the definition of subgenera within a genus is often the sign of an impending split. Therefore, those interested in these snakes would do well to familiarize themselves with these new subgenera. [2]

Related Research Articles

<span class="mw-page-title-main">Viperinae</span> Subfamily of snakes

Viperinae, or viperines, are a subfamily of vipers endemic to Europe, Asia and Africa. They are distinguished by their lack of the heat-sensing pit organs that characterize their sister group, the subfamily Crotalinae. Currently, 13 genera are recognized. Most are tropical and subtropical, although one species, Vipera berus, even occurs within the Arctic Circle. Like all vipers, they are venomous.

<span class="mw-page-title-main">Viperidae</span> Family of snakes

The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, and various other isolated islands. They are venomous and have long, hinged fangs that permit deep penetration and injection of their venom. Three subfamilies are currently recognized. They are also known as viperids. The name "viper" is derived from the Latin word vipera, -ae, also meaning viper, possibly from vivus ("living") and parere, referring to the trait viviparity common in vipers like most of the species of Boidae.

<i>Acanthophis</i> Genus of elapid snakes commonly called death adders

Acanthophis is a genus of elapid snakes. Commonly called death adders, they are native to Australia, New Guinea and nearby islands, and are among the most venomous snakes in the world. Despite their common name, they are not adders at all and belong to the Elapidae family. The name of the genus derives from the Ancient Greek akanthos/ἄκανθος ('spine') and ophis/ὄφις ('snake'), referring to the spine on the death adder's tail.

<span class="mw-page-title-main">Keeled scales</span> Reptile scales with ridges

Keeled scales refer to reptile scales that, rather than being smooth, have a ridge down the center that may or may not extend to the tip of the scale, making them rough to the touch. According to Street's (1979) description of European lizards and snakes, in those that have keeled scales the keels are usually stronger in male specimens and are consistently arranged according to the species of reptiles, even though many others do not have them. With European lizards, the dorsal scales are usually well keeled, while those on the flanks are more weakly keeled and those on the belly smooth. Non-European lizards such as Sphaerodactylus macrolepis also display keeled scales.

<span class="mw-page-title-main">Gaboon viper</span> Species of snake

The Gaboon viper, also called the Gaboon adder, is a highly venomous viper species found in the rainforests and savannas of sub-Saharan Africa. Like all other vipers, it is venomous. It is the largest member of the genus Bitis, and it has the longest fangs of any venomous snake – up to 2 inches (5 cm) in length – and the highest venom yield of any snake. No subspecies are recognized.

<i>Bitis nasicornis</i> Species of snake

Bitis nasicornis is a viper species belonging to the genus Bitis, part of a subfamily known as "puff-adders", found in the forests of West and Central Africa. This large viper is known for its striking coloration and prominent nasal "horns". No subspecies are currently recognized. Its common names include butterfly viper, rhinoceros viper, river jack and many more. Like all other vipers, it is venomous.

<span class="mw-page-title-main">Puff adder</span> Species of highly venomous snake

The puff adder is a highly venomous viper species found in savannahs and grasslands from Morocco and western Arabia throughout Africa except for the Sahara and rainforest regions. It is responsible for causing the most snakebite fatalities in Africa owing to various factors, such as its wide distribution, frequent occurrence in highly populated regions, and aggressive disposition. Like all other vipers, it is venomous. Two subspecies are currently recognized, including the nominate subspecies described here.

<i>Hypnale</i> Genus of snakes

Hypnale is a genus of venomous pit vipers endemic to Sri Lanka and southwestern India. Three monotypic species are currently recognized. All members have more or less upturned snouts that produce a hump-nosed effect.

<i>Trimeresurus albolabris</i> Species of snake

Trimeresurus albolabris, the white-lipped pit viper or white-lipped tree viper, is a venomous pit viper species endemic to Southeast Asia.

<i>Causus</i> Genus of snakes

Causus is a genus of vipers found only in sub-Saharan Africa. It is a group considered to be among the most primitive members of the family Viperidae based on head scalation, oviparity, venom apparatus, and because they have round pupils. However, this is contradicted by recent molecular studies. Seven species are currently recognized. They are commonly known as night adders. Like all other vipers, they are venomous.

Bitis arietans somalica also known as the Somali puff adder, is a venomous viper subspecies found only in Somalia, eastern Ethiopia, and northern Kenya. It is distinguished from B. a. arietans by its keeled subcaudals.

<span class="mw-page-title-main">Berg adder</span> Species of snake

The berg adder is a venomous viper species endemic to mountainous regions in southern Africa. No subspecies are currently recognized.

<span class="mw-page-title-main">Horned adder</span> Species of snake

The horned adder is a viper species. It is found in the arid region of southwest Africa, in Angola, Botswana, Namibia; South Africa, and Zimbabwe. It is easily distinguished by the presence of a single, large horn-like scale over each eye. No subspecies are currently recognized. Like all other vipers, it is venomous.

The Albany adder is a viper species. It was previously considered a subspecies of Bitis cornuta. Its range is restricted to eastern and southern Cape Province in South Africa. Like all vipers, it is venomous.

<i>Bitis schneideri</i> Species of snake

Bitis schneideri is a species of venomous snake in the subfamily Viperinae of the family Viperidae. The species is native to a small coastal region that straddles the border between Namibia and South Africa. B. schneideri is the smallest species in the genus Bitis and possibly the world's smallest viper. There are no subspecies that are currently recognized as being valid.

<i>Bitis parviocula</i> Species of snake

Bitis parviocula is a venomous viper species found only in Ethiopia. It is large with a broad head and spectacular geometric markings. In 1995, the species was known from only three specimens, but additional information has surfaced since then. Little is known about its natural history or its venom. No subspecies are currently recognized.

<i>Bitis peringueyi</i> Species of snake

Bitis peringueyi, also known as the Peringuey's adder, Peringuey's desert adder or desert sidewinding adder, is a venomous viper species found in Namibia and southern Angola. No subspecies are currently recognized.

<i>Bitis rhinoceros</i> Species of snake

Bitis rhinoceros is a viper species endemic to West Africa. Like all vipers, it is venomous. It can be easily distinguished from the closely related species B. gabonica by the presence of two large nasal "horns".

References

  1. 1 2 3 4 5 6 7 McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1. Washington, District of Columbia: Herpetologists' League. 511 pp. ISBN   1-893777-00-6 (series). ISBN   1-893777-01-4 (volume).[ page needed ]
  2. 1 2 3 4 5 6 7 8 9 10 11 Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Malabar, Florida: Krieger Publishing Company. 359 pp. ISBN   0-89464-877-2.[ page needed ]
  3. 1 2 Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Dubai: Ralph Curtis Books. Oriental Press. 192 pp. ISBN   0-88359-029-8.[ page needed ]
  4. 1 2 "Bitis". Integrated Taxonomic Information System . Retrieved 18 July 2006.
  5. 1 2 U.S. Navy. 1965. Poisonous Snakes of the World. Washington, District of Columbia: United States Government Printing Office. 212 pp.[ page needed ]
  6. Safer, Adam B; Grace, Michael S (2004). "Infrared imaging in vipers: Differential responses of crotaline and viperine snakes to paired thermal targets". Behavioural Brain Research. 154 (1): 55–61. doi:10.1016/j.bbr.2004.01.020. PMID   15302110. S2CID   39736880.
  7. Krochmal, Aaron R.; Bakken, George S.; LaDuc, Travis J. (2004). "Heat in evolution's kitchen: evolutionary perspectives on the functions and origin of the facial pit of pitvipers (Viperidae: Crotalinae)". Journal of Experimental Biology. 207 (24): 4231–8. doi:10.1242/jeb.01278. PMID   15531644.
  8. Bitis arietans antivenoms at Munich AntiVenom INdex. Accessed 25 August 2006.
  9. Bitis gabonica antivenoms at Munich AntiVenom INdex. Accessed 25 August 2006.
  10. Miami-Dade Fire Rescue Venom Response Unit Archived 20 December 2008 at the Wayback Machine at VenomousReptiles.org Archived 9 April 2008 at the Wayback Machine . Accessed 5 September 2006.
  11. Largen, M., and Spawls, S. 2010. The Amphibians and Reptiles of Ethiopia and Eritrea. Frankfurt am Main: Edition Chimara. ISBN   978-3-89973-466-9 [ page needed ]

Further reading