Bitis is a genus of vipers found in Africa and the southern Arabian Peninsula.
Members of the genus are commonly known as African adders, African vipers, or puff adders.
Description
Size variation within this genus is extreme, ranging from the very small B. schneideri, which grows to a maximum of and is perhaps the world's smallest viperid, to the very large B. gabonica, which can attain a length over and is the heaviest viper in the world.
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.
The rectilinear locomotion is very common in many Bitis species.
Reproduction
All members are viviparous and some give birth to large numbers of offspring. At least one protects specifically against bites from B. nasicornis: India Antiserum Africa Polyvalent. In the past, such antivenoms have been used to treat bites from other Bitis species, but with mixed results.
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|B. peringueyi
|(Boulenger, 1888)
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|Peringuey's desert adder
|The Namib Desert from southern Angola to Lüderitz, Namibia
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|B. rhinoceros
|style="width:13%"|(Schlegel, 1855)
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|West African Gaboon viper
|style="width:50%"|Guinea, Guinea-Bissau, Liberia, Sierra Leone, Ivory Coast, Ghana, Togo
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|B. rubida
|Branch, 1997
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|Red adder
|Several isolated populations in the northern Cape Fold Mountains and inland escarpment in Western Cape Province, South Africa
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|B. schneideri
|(Boettger, 1886)
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|Namaqua dwarf adder
|White coastal sand dunes from Namibia, near Lüderitz, south to Hondeklip Bay, Little Namaqualand, South Africa
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|B. worthingtoni
|Parker, 1932
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|Kenya horned viper
|Restricted to Kenya's high central Rift Valley at altitudes over 1500 m
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|B. xeropaga
|Haacke, 1975
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|Desert mountain adder
|Northwestern 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
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*) Not including the nominate subspecies.<br />
<span style="font-size:100%;"><sup>T</sup></span>) 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: