Английская Википедия:Horned adder

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The horned adder (Bitis caudalis) is a viper species.[1][2] It is found in the arid region of southwest Africa, in Angola, Botswana, Namibia; South Africa, and Zimbabwe.[1] It is easily distinguished by the presence of a single, large horn-like scale over each eye.Шаблон:Citation needed No subspecies are currently recognized.[2][3] Like all other vipers, it is venomous.

Common names

The species is commonly known as the horned adder,[1][2][4] horned puff adder,[5] or horned viper.[6]

Description

A short, stout little viper, it usually averages Шаблон:Convert in total length (body + tail). The largest specimen reported being seen is a female from southern Botswana measuring Шаблон:Convert total length.[4]

Geographic range

The snake is found in far arid regions of southwest Africa: southwest 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.

Its type locality is given as "... the sandy districts north of the Cape Colony..." [South Africa].[7]

Habitat

Horned adders are mostly found in sparsely vegetated desert and semiarid scrub country.[4]

Venom

Bites are assumed to be rare and no epidemiological data are available.[5] Little information is available regarding the toxicity and amount of venom produced. Spawls and Branch (1995) reported an average yield of 85 mg of wet venom,[4] while Christensen (1971) offered an Шаблон:LD50 value of 1.2 mg/kg IV.[8] Other research has found the LD50Шаблон:Ambiguous to be between 0.15 and 0.22 mg/kg [9]

Based on this LD50 value, Spawls and Branch (1995) estimated about 300 mg of this venom would be required to kill an adult. They regarded this venom as one of the weakest of the genus,[4] although 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) suggested it is highly toxic and a number of deaths have occurred as a result.[6][10] 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.[5]

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.[11] According to the U.S. Navy (1965, 1991),[6][10] polyvalent antivenins produced by SAIMR and the Pasteur Institute are said to be effective, while Mallow et al. (2003) reported currently available antivenins are of limited effectiveness.[5]

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.[5]

Taxonomy

A number of authors, including Mertens (1955), use a trinomial to refer to this species, even though no subspecies are recognized.[7]

References

Шаблон:Reflist

Further reading

Шаблон:Refbegin

  • Branch, Bill. 2004. Field Guide to Snakes and Other Reptiles of Southern Africa. Sanibel Island, Florida: Ralph Curtis Books. 399 pp. Шаблон:ISBN. (Bitis caudalis, p. 116 + Plate 13.)
  • 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 Bücherl W, Deulofeu V, Buckley EE. Venomous Animals and Their Venoms, Vol. I. New York: Academic Press. pp. 437–462. Шаблон:ISBN.
  • Smith A. 1839. Illustrations of the Zoology of South Africa; Consisting Chiefly of Figures and Descriptions of the Objects of Natural History Collected during an Expedition into the Interior of South Africa, in the Years 1834, 1835, and 1836; Fitted out by "The Cape of Good Hope Association for Exploring Central Africa:" together with a Summary of African Zoology, and an Inquiry into the Geographical Ranges of Species in that Quarter of the Globe. [Volume 3.] London: Lords Commissioners of Her Majesty's Treasury. (Smith, Elder and Co., printers.) 48 Plates + unnumbered pages of text. (Vipera caudalis, Plate 7.)
  • 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): 715–737.

Шаблон:Refend

External links

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  1. ↑ 1,0 1,1 1,2 Ошибка цитирования Неверный тег <ref>; для сносок IUCN не указан текст
  2. ↑ 2,0 2,1 2,2 Шаблон:NRDB species
  3. ↑ Шаблон:ITIS
  4. ↑ 4,0 4,1 4,2 4,3 4,4 Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. Шаблон:ISBN.
  5. ↑ 5,0 5,1 5,2 5,3 5,4 Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. 359 pp. Шаблон:ISBN.
  6. ↑ 6,0 6,1 6,2 U.S. Navy. 1991. Poisonous Snakes of the World. US Government. New York: Dover Publications Inc. 203 pp. Шаблон:ISBN.
  7. ↑ 7,0 7,1 Ошибка цитирования Неверный тег <ref>; для сносок McD99 не указан текст
  8. ↑ Brown JH. 1973. Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. Шаблон:ISBN.
  9. ↑ C Y Lee et al. 1982. "Site of action of caudoxin, a neurotoxic phospholipase A2 from the horned puff adder (Bitis caudalis) venom". Toxicon, 20(3), 637-647
  10. ↑ 10,0 10,1 U.S. Navy. 1965. Poisonous Snakes of the World. US Government. Washington, District of Columbia: US Govt. Printing Office. 212 pp.
  11. ↑ Bitis caudalis at Munich AntiVenom INdex (MAVIN). Accessed 21 April 2007.
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