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 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 dangeroussome 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]

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 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. Bibcode:2004JExpB.207.4231K. 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