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Cerastes cerastes

Cerastes cerastes, Photo: Michael Lahanas

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Reptilia
Subclassis: Diapsida
Infraclassis: Lepidosauromorpha
Superordo: Lepidosauria
Ordo: Squamata
Subordo: Serpentes
Infraordo: Caenophidia
Superfamilia: Viperoidea
Familia: Viperidae
Subfamilia: Viperinae
Genus: Cerastes
Species: C. cerastes

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Cerastes cerastes is a venomous viper species native to the deserts of Northern Africa and parts of the Middle East. They often are easily recognized by the presence of a pair of supraocular horns, although hornless individuals do occur.[2] No subspecies are currently recognized.[4]


Description

The average length is 30–60 cm (0.98–2.0 ft), with a maximum of 85 cm (33 in). Females are larger than males.[2]

One of the most distinctive characteristics of this species are the supraorbital horns, one over each eye. However, these are either present, reduced in size or absent (see Cerastes).[2] The eyes are prominent and set on the side of the head.[5] There is significant sexual dimorphism, with males having larger heads and larger eyes than females. Compared to C. gasperettii, the relative head size of C. cerastes is larger and there is a greater frequency of horned individuals (13% versus 48% respectively).[2][6]

The color pattern consists of a yellowish, pale gray, pinkish, redish or pale brown ground color that almost always matches the substrate color where the animal is found. Dorsally, a series of dark, semi-rectangular blotches run the length of the body. These may or may not be fused into crossbars. The belly is white and the tail may have a black tip, the tail is usually thin.[2][5]

Common names

Common names of this species include Saharan horned viper,[2] horned desert viper,[3] Sahara horned viper,[5] desert horned viper, North African horned viper,[7] African desert horned viper, greater cerastes,[8] asp and horned viper.[9] In Egypt it is called el-ṭorîsha (حية الطريشة).

Geographic range

Arid north Africa (Morocco, Western Sahara, Mauritania and Mali, eastward through Algeria, Tunisia, Niger, Libya and Chad to Egypt, Sudan, Ethiopia and Somalia) through Sinai to the northern Negev of Israel. In the Arabian Peninsula, it occurs in Yemen, extreme southwestern Saudi Arabia and parts of the country in Qatar where it is sympatric with C. gaperettii. A report of this species being found in Lebanon is unlikely, according to Joger (1984). Originally, the type locality was listed only as "Oriente." However, Flower (1933) proposed "Egypt" by way of clarification.[1]

Habitat

These snakes favor dry, sandy areas with sparse rock outcroppings, and tend not to prefer coarse sand. Occasionally, they are found around oases, and up to an altitude of 1500 m. Cooler temperatures, with annual averages of 20°C or less, are preferred .[2]

Behavior

They typically move about by sidewinding, during which they press their weight into the sand or soil, leaving whole-body impressions. Often, it is even possible to use these impressions to make ventral scale counts. They have a reasonably placid temperament, but if threatened, they may assume a C-shaped posture and rapidly rub their coils together. Having strongly keeled scales, this produces a rasping noise, similar to Echis. They are capable of striking quickly.[2]

Reproduction

In captivity, mating was observed in April and always occurred while the animals were buried in the sand.[2] This species is oviparous, laying 8-23 eggs that hatch after 50 to 80 days of incubation. The eggs are laid under rocks and in abandoned rodent burrows. The hatchlings measure 12–15 cm in length.[5]

Venom

C. cerastes venom is not very toxic, although it is reported to be similar in action to Echis venom.[2] Envenomation usually causes swelling, hemorrhage, necrosis, nausea, vomiting and hematuria. A high phospholipase A2 content may cause cardiotoxicity and myotoxicity.[5] Studies of venom from both C. cerastes and C. vipera list a total of eight venom fractions, the most powerful of which has hemorrhagic activity. Venom yields vary, with ranges of 19–27 mg to 100 mg of dried venom being reported.[2] For venom toxicity, Brown (1973) gives LD50 values of 0.4 mg/kg IV and 3.0 mg/kg SC.[7] An estimated lethal dose for humans is 40–50 mg.[5]

Taxonomy

A number of subspecies may be encountered in literature:[2]

* C. c. hoofieni - Werner & Sivan, 1999 - Saudi Arabia.
* C. c. karlhartli - Sochurek, 1974 - Egyptian horned viper - southeast Egypt and Sinai Peninsula.
* C. c. mutila - Domergue, 1901 - Algerian horned viper - southwest Algeria, Morocco.

Previously, C. gasperettii was also regarded as a subspecies of C. cerastes.[2]

References

1. ^ a b 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 f g h i j k l m n Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company. 359 pp. ISBN 0-89464-877-2.
3. ^ a b Mehrtens JM. 1987. Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. ISBN 0-8069-6460-X.
4. ^ "Cerastes cerastes". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=634963. Retrieved 30 July 2006.
5. ^ a b c d e f Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. ISBN 0-88359-029-8.
6. ^ Werner YL, Verdier A, Rosenman D, Sivan N. 1991. Systematics and zoogeography of Cerastes (Ophidia: Viperidae) in the Levant: 1, Distinguishing Arabian from African "Cerastes cerastes." The Snake 23:90-100.
7. ^ a b 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. ^ U.S. Navy. 1991. Poisonous Snakes of the World. US Govt. New York: Dover Publications Inc. 203 pp. ISBN 0-486-26629-X.
9. ^ Ditmars RL. 1933. Reptiles of the World. Revised Edition. The MacMillan Company. 329 pp. 89 plates.


Further reading

* Calmette A. 1907. Les venins, les animaux venimeux et la serotherapie antivenimeuse. In: Bucherl W. editor. 1967. Venomous Animals and Their Venoms. Vol. I. Paris: Masson. pp 233.
* Mohamed AH, Kamel A, Ayobe MH. 1969. "Studies of phospholipase A and B activities of Egyptian snake venoms and a scorpion venom". Toxicon 6:293-8.
* Joger U. 1984. The Venomous Snakes of the Near and Middle East. Wiesbaden: Dr. Ludwig Reichert Verlag. 175 pp.
* Labib RS, Malim HY, Farag NW. 1979. "Fractionation of Cerastes cerastes and Cerastes vipera snake venoms by gel filtration and identification of some enzymatic and biological activities". Toxicon 17:337-45.
* Labib RS, Azab MH, Farag NW. 1981. "Effects of Cerastes cerastes (Egyptian sand viper) snake venoms on blood coagulation: separation of coagulant and anticoagulant factors and their correlation with arginineesterase protease activities". Toxicon 19:85-94.
* Labib RS, Azab ER, Farag NW. 1981. "Proteases of Cerastes cerastes and Cerastes vipera snake venoms". Toxicon 19:73-83.
* Schneemann M, Cathomas R, Laidlaw ST, El Nahas AM, Theakston RDG, Warrell DA. 2004. "Life-threatening envenoming by the Saharan horned viper (Cerastes cerastes) causing micro-angiopathic haemolysis, coagulopathy and acute renal failure: clinical cases and review". Association of Physicians. QJM vol. 97 no. 11. Full text at Oxford Journals. Accessed 9 March 2007.
* Schnurrenburger H. 1959. "Observations on behavior in two Libyan species of viperine snake". Herpetologica 15:70-2.
* U.S. Navy. 1991. Poisonous Snakes of the World. New York: Dover Books. (Reprint of US Govt. Printing Office, Washington D.C.) 133 pp. ISBN 0-486-26629-X.

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