| Bitis | |
|---|---|
 | |
| Bitis arietans | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Viperidae |
| Subfamily: | Viperinae |
| Genus: | Bitis Gray, 1842 |
 | |
| Synonyms[1] | |
| |
Bitis is agenus ofvipers found inAfrica and the southernArabian Peninsula.[1] It includes the largest and the smallest vipers in the world. Members are known for their characteristicthreat displays that involve inflating and deflating their bodies while hissing and puffing loudly.[2] Thetype species for this genus isB. arietans,[1] which is also the most widely distributed viper in Africa.[3] Currently, 18species are recognized.[4]
Members of the genus are commonly known asAfrican adders,[2]African vipers,[3] orpuff adders.
Size variation within this genus is extreme, ranging from the very smallB. schneideri, which grows to a maximum of 28 cm (11 in) and is perhaps the world's smallestviperid, to the very largeB. 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. Thecanthus is also distinct. A number of species have enlargedrostral orsupraorbital 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 andnasal 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 withkeeled scales that are imbricated (overlapping) with apical pits. At midbody, thedorsal scales number 21–46. Laterally, the dorsal scales may be slightly oblique. Theventral scales, which number 112–153, are large, rounded, and sometimes have slight lateral keels. Their tails are short. Theanal scale is single. The pairedsubcaudal scales number 16-37 and are sometimes keeled laterally.[2][5]
Puff adders are found inAfrica and the southernArabian Peninsula.[1]
Bitis species are known for their behavior of inflating and deflating their bodies in loud hissing or puffing threat displays. They areterrestrial ambush predators, and appear sluggish, but can strike with amazing speed.[2] In contrast to the pitvipers of the subfamilyCrotalinae,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]
Therectilinear locomotion is very common in manyBitis species.
All members areviviparous and some give birth to large numbers of offspring.[2]
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 againstB. arietans and four also coverB. gabonica.[8][9] At least one protects specifically against bites fromB. nasicornis: India Antiserum Africa Polyvalent.[10] In the past, such antivenoms have been used to treat bites from otherBitis species, but with mixed results.[2]
| Image | Species[1] | Taxon author[1] | Subsp.*[4] | Common name | Geographic range[1] |
|---|---|---|---|---|---|
| B. albanica | Hewitt, 1937 | 0 | Albany adder | Republic of South Africa, Eastern Cape Province from Port Elizabeth to near Committees. | |
 | B. arietansT | (Merrem, 1820) | 1 | Puff adder | Most ofsub-Saharan Africa south to theCape of Good Hope, including southernMorocco,Mauritania,Senegal,Mali, southernAlgeria,Guinea,Sierra Leone,Ivory Coast,Ghana,Togo,Benin,Niger,Nigeria,Chad,Sudan,Cameroon,Central African Republic, northern, eastern and southernDemocratic Republic of the Congo,Uganda,Kenya,Somalia,Rwanda,Burundi,Tanzania,Angola,Zambia,Malawi,Mozambique,Zimbabwe,Botswana,Namibia,South Africa, also occurs on theArabian peninsula, where it is found in southwesternSaudi Arabia andYemen |
 | B. armata | (A. Smith, 1826) | 0 | Southern adder | Republic of South Africa, SouthwesternWestern Cape, fromWest Coast National Park toDe Hoop Nature Reserve |
 | B. atropos | (Linnaeus,1758) | 0 | Berg adder | Isolated populations in the mountainous areas ofsouthern Africa: the Inyanga Highlands andChimanimani Mountains of eastern Zimbabwe and nearby Mozambique, in South Africa along theDrakensberg Escarpments in the provinces of Transvaal, westernNatal,Lesotho and easternFree State, and in the southern coastal mountains of western and easternCape Province |
 | B. caudalis | (A. Smith, 1839) | 0 | Horned adder | The arid region of southwest Africa: southwest Angola, Namibia, across theKalahari Desert of southern Botswana, into northernTransvaal and southwestern Zimbabwe, in South Africa from the northern Cape Province south to theGreat Karoo |
 | B. cornuta | (Daudin, 1803) | 0 | Many-horned adder | The coastal region of southwest Namibia through west and southwest Cape Province in South Africa, with a few isolated populations in eastern Cape Province |
 | B. gabonica | (A.M.C. Duméril,Bibron &A.H.A. Duméril, 1854) | 0 | Gaboon viper | Guinea, Ghana, Togo, Nigeria, Cameroon, DR Congo, Central African Republic, southern Sudan, Uganda, Kenya, eastern Tanzania, Zambia, Malawi, eastern Zimbabwe, Mozambique, northeastKwaZulu-Natal Province in South Africa |
| B. harenna | Gower, Wade, Spawls, Böhme, Buechley, Sykes, & Colston, 2016 | 0 | Bale Mountains adder | Ethiopia | |
| B. heraldica | (Bocage, 1889) | 0 | Angolan adder | The high plateau of central Angola | |
 | B. inornata | (A. Smith, 1838) | 0 | Plain mountain adder | Isolated population on theSneeuberge, eastern Cape Province, South Africa |
 | B. nasicornis | (Shaw, 1792) | 0 | Rhinoceros viper | From Guinea to Ghana inWest Africa, and inCentral Africa in the Central African Republic, southern Sudan, Cameroon, Gabon, Congo, DR Congo, Angola, Rwanda, Uganda and western Kenya |
 | B. parviocula | Böhme, 1977 | 0 | Ethiopian mountain adder | Known from only five localities in the highlands to southwestEthiopia, at altitudes of 1700–2800 m.[11] |
 | B. peringueyi | (Boulenger, 1888) | 0 | Peringuey's desert adder | TheNamib Desert from southern Angola to Lüderitz, Namibia |
.jpg) | B. rhinoceros | (Schlegel, 1855) | 0 | West African Gaboon viper | Guinea, Guinea-Bissau, Liberia, Sierra Leone, Ivory Coast, Ghana, Togo |
 | B. rubida | Branch, 1997 | 0 | Red adder | Several isolated populations in the northern Cape Fold Mountains and inland escarpment inWestern Cape Province, South Africa |
 | B. schneideri | (Boettger, 1886) | 0 | Namaqua dwarf adder | White coastal sand dunes from Namibia, nearLüderitz, south to Hondeklip Bay,Little Namaqualand, South Africa |
 | B. worthingtoni | Parker, 1932 | 0 | Kenya horned viper | Restricted to Kenya's high central Rift Valley at altitudes over 1500 m |
 | B. xeropaga | Haacke, 1975 | 0 | Desert mountain adder | Northwestern Cape Province in South Africa and the arid mountains of the lower Orange River basin, north into southern Namibia andGreat Namaqualand as far as Aus |
*) Not including the nominate subspecies.
T)Type species.
Lenk et al. (1999) used molecular data (immunological distances and mitochondrial DNA sequences) to estimate the phylogenetic relationships among species ofBitis. They identified four major monophyletic groups for which they created foursubgenera:[2]
| National | |
|---|---|
| Other | |
