''Cerastes'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of small,

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

vipers found in the

desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...

s and semi-deserts of northern

North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...

eastward through

Arabia The Arabian Peninsula, (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") or Arabia, is a peninsula of Western Asia, situated northeast of Africa on the Arabian Pl ...

and

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

. Three

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

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 interagen ...

, 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 dinosaurs). The database focuses on species (as opposed to higher ranks such as families) and has entrie ...

.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 Publ ...

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 Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes ...

, with the

Negev desert The Negev or Negeb (; he, הַנֶּגֶב, hanNegév; ar, ٱلنَّقَب, an-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 southe ...

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 an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

and

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

(not known to climb into

bushes A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

), 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 electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) sy ...

Feeding behavior and diet

These are ambush predators 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 Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s, and

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia altho ...

Reproduction

All three species lay eggs. 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, polemicist, and conductor who is chiefly known for his operas (or, as some of his mature works were later known, "music dramas"). Unlike most op ...

& 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