''Cerastes'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of small

viper Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous and have long (relative to non-vipe ...

s found in the

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

s and semi-deserts of northern

North Africa North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...

eastward through

Arabia The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world. Geographically, the ...

and

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

. Three

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

are currently recognized by

ITIS The Integrated Taxonomic Information System (ITIS) is an American partnership of federal agencies designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagenc ...

, and an additional recently described species is recognized by the

Reptile Database The Reptile Database is a scientific database that collects taxonomic information on all living reptile species (i.e. no fossil species such as dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared ...

.The Reptile Database. www.reptile-database.org. Common names for members the genus include horned vipers,Mallow D, Ludwig D, Nilson G. 2003. ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. 359 pp. . North African desert vipers,Spawls S, Branch B. 1995. ''The Dangerous Snakes of Africa''. Dubai: Ralph Curtis Books. Oriental Press. 192 pp. . and cerastes vipers. Parker HW, Grandison AGC. 1977. ''Snakes – a natural history''. Second Edition. London and Ithaca: British Museum (Natural History) and Cornell University Press. 108 pp. + 16 plates. LCCCN 76-54625. (cloth), (paper).

Description

''Cerastes'' are small snakes, averaging less than in total length (body + tail), but are relatively stout in appearance. The head is broad, flat and distinct from the neck. The head is covered with tubercularly keeled scales, which usually number 15 or more across, and a supraorbital horn may be present over each eye in some species. The snout is short and wide and the eyes, which are set well forward, are small to moderate in size. The body is short, stout and cylindrically depressed. The tail is short and tapers abruptly behind the vent. The

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...

are small, keeled, in 23-35 rows at midbody, with the keels of the oblique lateral row being serrated. Although ''Cerastes'' are often referred to as horned vipers, only the two larger species, ''C. cerastes'' and ''C. gasperettii'', are known to have horns, and even these do not always have them. Individuals with and without horns occur within the same population and even within the same litter. When present, each horn consists of a single long, spine-like scale that can be folded back into an indentation in the postocular scale. They fold back in response to direct stimulation, thus streamlining the head and easing passage through burrows. Horns occur more often in individuals from sandy deserts as opposed to stony deserts. Specimens without horns have a prominent brow ridge instead. The purpose of the horns is the subject of much speculation. One theory is that they allow a buildup of sand above the eyes while keeping it out of the eyes themselves. Another, more recent theory is simply that the horns serve to break up the outline of the head, making them harder for prey animals to spot.

Geographic range

They are found in

eastward through

and

. Mallow et al. (2003) describe the genus as being restricted to the deserts of North Africa and southwestern Asia, with the

Negev desert The Negev ( ; ) or Naqab (), is a desert and semidesert region of southern Israel. The region's largest city and administrative capital is Beersheba (pop. ), in the north. At its southern end is the Gulf of Aqaba and the resort town, resort city ...

acting as a filter zone between the three species mentioned in the table below.

Habitat

Desert and semi-desert.

Behavior

This genus is

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

and terrestrial (not known to climb into bushes), often hiding by burying themselves in the sand. Although often described as slow moving, these snakes are also capable of sidewinding. When doing so, they can move quickly across the sand. ''Cerastes'' species are not known to be particularly ill-tempered ("fairly placid"), but when threatened they will often stand their ground and form C-shaped coils that are rubbed together to produce a rasping or crackling sound, similar to '' Echis''. This is called

stridulation Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mech ...

. With enough provocation, they will strike from this position. These snakes are capable of "sinking" quickly down into loose sand, using their keeled, angled and serrated lateral scales in a rocking motion. This process begins at the tail and moves forward until the entire head is buried and only the eyes and nostrils are exposed. They can bury themselves this way whether in an outstretched or a coiled position. See

video Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, whi ...

Feeding behavior and diet

These are ambush

predators Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

that lie buried in the sand, waiting for prey to pass by. Their diet consists mainly of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s, and

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

Reproduction

All three species lay

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

s. However, those of ''C. vipera'' hatch within hours of deposition as opposed to many weeks, something not previously observed in other African snakes, most of which lay eggs that hatch weeks later or give birth to live young.

Species

In addition to the three above species recognized by "ITIS", the Reptile Database also recognizes '' Cerastes boehmei''

Wagner Wilhelm Richard Wagner ( ; ; 22 May 181313 February 1883) was a German composer, theatre director, essayist, and conductor who is chiefly known for his operas (or, as some of his mature works were later known, "music dramas"). Unlike most o ...

& Wilms, 2010.Wagner P, Wilms TM. 2010. A crowned devil: new species of ''Cerastes'' Laurenti, 1768 (Ophidia, Viperidae) from Tunisia, with two nomenclatural notes. ''Bonn Zool. Bull.'' 57 (2): 297-306.

Taxonomy

Although it would seem that Laurenti changed his mind in 1768 and decided to name this genus ''Aspis'', instead of ''Cerastes'' as he did earlier, this was eventually rejected. The

International Commission on Zoological Nomenclature The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries. Orga ...

(ICZN) later placed the name ''Cerastes'' on the Official List of Generic Names in Zoology (name no. 1539), while the name ''Aspis'' was placed on the Official Index of Invalid Generic Names in Zoology (name no. 1630).

References

External links

* {{Taxonbar, from=Q73178 Articles containing video clips Snake genera Viperinae Taxa named by Josephus Nicolaus Laurenti