Bitis caudalis

Bitis caudalis
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Viperidae
Subfamily:	Viperinae
Genus:	Bitis
Species:	B. caudalis
Binomial name
Bitis caudalis (Smith, 1839)
Synonyms
Vipera ocellata - A. Smith, 1838 Vipera (Cerates) caudalis - A. Smith, 1839 Vipera caudalis - A. Smith, 1839 Cerastes caudalis - Gray, 1842 Vipera caudalis - Jan, 1859 V[ipera]. (Cerastes) caudalis - Jan, 1863 Bitis caudalis - Boulenger, 1896 Cobra caudalis - Mertens, 1937 Bitis caudalis caudalis - Mertens, 1955 Bitis caudalis - Branch, 1991[1]

Common names: horned adder,^[2][3] horned puff adder,^[4] horned viper.^[5]

Bitis caudalis is a venomous viper species found in the arid region of south-west Africa. Easily distinguished by the presence of a single, large horn-like scale over each eye. No subspecies are currently recognized.^[6]

Description

B. caudalis, juvenile.

A short and stout little viper that usually averages 30–40 cm in length. The largest specimen reported is a female from southern Botswana measuring 51.5 cm.^[2]

Geographic range

The arid region of south-west Africa: south-west Angola, Namibia, across the Kalahari Desert of southern Botswana, into northern Transvaal and southwestern Zimbabwe. In South Africa it is found from the northern Cape Province south to the Great Karoo. Type locality: "... the sandy districts north of the Cape Colony..." [South Africa].^[1]

Habitat

Mostly found in sparsely vegetated desert and semi-arid scrub country.^[2]

Venom

Bites are assumed to be rare and no epidemiological information is available.^[4] Little information is available regarding the toxicity and amount of venom produced. Spawls and Branch (1995) report an average yield of 85 mg of wet venom,^[2] while Christensen (1971) offers an LD₅₀ value of 1.2 mg/kg IV.^[7]

Based on this LD₅₀ value, Spawls and Branch (1995) estimated that about 300 mg of this venom would be required to kill an adult. They regard this venom as one of the weakest of the genus^[2] although it must be mentioned that the tests are conducted solely on mice which might have a different reaction from humans to the venom. On the other hand, an older report by the U.S. Navy (1965, 1991) suggests that it is highly toxic and that a number of deaths have occurred as a result.^[5][8] According to Broadley and Cock (1975), envenomation symptoms in humans include swelling, severe pain, nausea, vomiting and shock. Blisters and necrotic ulcers may form around the bite site.^[4]

The National Antivenom and Vaccine Production Centre in Riyadh, Saudi Arabia, produces a polyvalent antivenin that includes a paraspecific antibody that protects against bites from this species.^[9] According to the U.S. Navy (1965, 1991),^[5][8] polyvalent antivenins produced by SAMIR and the Pasteur Institute are said to be effective, while Mallow et al. (2003) report that currently available antivenins are of limited effectiveness.^[4]

Viljoen et al. (1982) isolated a protein, a neurotoxic phospholipase A₂, from the venom, which they called "caudoxin". According to Lee et al. (1983), this is a presynaptic toxin similar to bungarotoxin, but with different binding sites.^[4]

Taxonomy

A number of authors, including Mertens (1955), use a trinomial to refer to this species, even though no subspecies are recognized.^[1]

See also

• List of viperine species and subspecies
• Viperinae by common name
• Viperinae by taxonomic synonyms
• Snakebite

References

1. ^ ^{a b c} McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
2. ^ ^{a b c d e} Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. ISBN 0-88359-029-8.
3. ^ Bitis caudalis at the Reptarium.cz Reptile Database. Accessed 2 August 2007.
4. ^ ^{a b c d e} Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. 359 pp. ISBN 0-89464-877-2.
5. ^ ^{a b c} U.S. Navy. 1991. Poisonous Snakes of the World. US Govt. New York: Dover Publications Inc. 203 pp. ISBN 0-486-26629-X.
6. ^ "Bitis caudalis". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=634951. Retrieved 25 July 2006. 
7. ^ Brown JH. 1973. Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. ISBN 0-398-02808-7.
8. ^ ^{a b} U.S. Navy. 1965. Poisonous Snakes of the World. US Govt. Printing Office, Washington D.C. 212 pp.
9. ^ Bitis caudalis at Munich AntiVenom INdex. Accessed 21 April 2007.

Further reading

• Broadley DG, Cock EV. 1975. Snakes of Rhodesia. Zimbabwe: Longman Zimbabwe Ltd. 126 pp. ASIN B0006CM8SE.
• Christensen PA. 1971. The venoms of Central and South Africa. In Venomous Animals and Their Venoms, Vol I, by Bücherl W, Deulofeu V, Buckley EE. New York: Academic Press. pp. 437–462. ISBN 0-12-138902-2.
• Viljoen CC, Botes DP, Kruger H. 1982. Isolation and characterization of the amino acid sequence of caudoxin, a presynaptic acting toxic phospholipase A2 from the venom of the horned puff adder (Bitis caudalis). Toxicon 20(4):715-37.

External links

• Video of B. caudalis and B. cornuta on YouTube. Accessed 1 March 2007.
• Video of B. caudalis drinking on YouTube. Accessed 1 March 2007.