''Echis'' (common names: saw-scaled vipers, carpet vipers
[Spawls S, Branch B. 1995. ''The Dangerous Snakes of Africa''. Dubai: Ralph Curtis Books. Oriental Press. 192 pp. .]) is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
viper
The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, and various other isolated islands. They are venomous and have long (relative to non-vipers), hinged fangs tha ...
s found in the dry regions of
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
,
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
,
Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
and
Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
. They have a characteristic threat display, rubbing sections of their body together to produce a "sizzling" warning sound.
[Mallow D, Ludwig D, Nilson G. 2003. ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. 359 pp. .] The name ''Echis'' is the Latin transliteration of the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
word for "viper" (''ἔχις''). Like all vipers, they are
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 ...
. Their common name is "saw-scaled vipers" and they include some of the species responsible for causing the most
snakebite
A snakebite is an injury caused by the bite of a snake, especially a venomous snake. A common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. Sometimes venom injection from the bite may occu ...
cases and deaths in the world.
[Campbell JA, Lamar WW. 2004. ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publishing Associates. 870 pp. 1500 plates. .] Twelve
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 appropriate s ...
are currently recognized.
Description
![Echis carinatus gab](https://upload.wikimedia.org/wikipedia/commons/6/69/Echis_carinatus_gab.png)
Saw-scaled vipers are relatively small snakes, the largest species (''
E. leucogaster,
E. pyramidum'') usually below long, and the smallest (''
E. hughesi,
E. jogeri'') being around .
The head is relatively small and is short, wide, pear-shaped and distinct from the neck. The snout is short and rounded, while the eyes are relatively large and the body is moderately slender and cylindrical. 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 mostly
keeled. However, the scales on the lower flanks stick out at a distinct 45° angle and have a central ridge, or keel, that is serrated (hence the common name). The tail is short and the
subcaudals
In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...
are single.
A saw-scaled viper of the genus ''Echis'' may be responsible for biblical claims of a
fiery flying serpent
The fiery flying serpent (Hebrew: ''sārāf mə‘ōfēf'') is a creature mentioned in the Book of Isaiah in the Tanakh.
The term translated as "fiery serpent", ', appears elsewhere in the Book of Isaiah to signify the seraphim, the singular fo ...
.
Geographic range
Species of this genus are found in
Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
, India (in rocky regions of
Maharashtra
Maharashtra (; , abbr. MH or Maha) is a states and union territories of India, state in the western India, western peninsular region of India occupying a substantial portion of the Deccan Plateau. Maharashtra is the List of states and union te ...
,
Rajasthan
Rajasthan (; lit. 'Land of Kings') is a state in northern India. It covers or 10.4 per cent of India's total geographical area. It is the largest Indian state by area and the seventh largest by population. It is on India's northwestern si ...
,
Uttar Pradesh
Uttar Pradesh (; , 'Northern Province') is a state in northern India. With over 200 million inhabitants, it is the most populated state in India as well as the most populous country subdivision in the world. It was established in 1950 ...
, and
Punjab
Punjab (; Punjabi: پنجاب ; ਪੰਜਾਬ ; ; also romanised as ''Panjāb'' or ''Panj-Āb'') is a geopolitical, cultural, and historical region in South Asia, specifically in the northern part of the Indian subcontinent, comprising ...
) and
Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
, parts of the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
, and
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
north of the equator.
Behaviour
All members of this genus have a distinctive threat display, which involves forming a series of parallel, C-shaped coils and rubbing their scales together to produce a sizzling sound, rather like water on a hot plate.
The proper term for this is
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 ...
.
[Mehrtens JM. 1987. ''Living Snakes of the World in Color.'' New York: Sterling Publishers. 480 pp. .] As they become more agitated, this stridulating behavior becomes faster and louder. This display is thought to have evolved as a means of limiting water loss, such as might occur when hissing.
However, some authors describe this display as being accompanied by loud hissing.
These snakes can be fierce and will strike from the position described above. When doing so, they may overbalance and end up moving towards their aggressor (an unusual behavior for snakes).
Saw-scaled vipers are highly aggressive compared to many of their cousins and they commonly strike to bite.
Diet
Little is known about the diets of some ''Echis'' species. For others, their diets are reported to be extremely varied, and may include items such as
locust
Locusts (derived from the Vulgar Latin ''locusta'', meaning grasshopper) are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstanc ...
s,
beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s,
worm
Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always).
Worms vary in size from microscopic to over in length for marine polychaete wor ...
s,
slug
Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a smal ...
s,
spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s,
scorpion
Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always end ...
s,
centipede
Centipedes (from New Latin , "hundred", and Latin , " foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', lip, and New Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, an ...
s,
solifugids
Solifugae is an order of animals in the class Arachnida known variously as camel spiders, wind scorpions, sun spiders, or solifuges. The order includes more than 1,000 described species in about 147 genera. Despite the common names, they are nei ...
,
frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
s,
toad
Toad is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands.
A distinction between frogs and toads is not made in scientif ...
s,
reptile
Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...
s (including other
snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
s), small
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s, and
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 lightweigh ...
s.
Reproduction
Most ''Echis'' species, such as those found in
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, are
oviparous
Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...
, while others, such as those in India, are
viviparous
Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the m ...
.
Venom
The
snake venom
Snake venom is a highly toxic saliva containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is injected by unique fangs during a bite, whereas some species are a ...
of ''Echis'' species consists mostly of four types of toxins:
neurotoxins
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nerv ...
,
cardiotoxins
Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by chemotherapy (a usual example is th ...
,
hemotoxins
Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells, disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term ''hemotoxin'' is to some degree a misnomer since toxins that damage t ...
, and
cytotoxins
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa'').
Cell physiology
Treating cell ...
. The genus is recognized as medically significant in many tropical rural areas. They are widespread and live in areas lacking modern medical facilities. Most victims are bitten after dark when these snakes are active.
Most of these species have venom that contains factors that can cause a consumption
coagulopathy
Coagulopathy (also called a bleeding disorder) is a condition in which the blood's ability to coagulate (form clots) is impaired. This condition can cause a tendency toward prolonged or excessive bleeding (bleeding diathesis), which may occur spo ...
and
defibrination, which may persist for days to weeks. This may result in bleeding anywhere in the body, including the possibility of an intracranial
hemorrhage
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
. The latter classically occurs a few days following the bite.
[Campbell CH. 1995. "Snake bite and snake venoms: their effects on the nervous system". In: de Wolff FA, editor. ''Handbook of clinical neurology, vol 21 (65). Intoxications of the nervous system, part II''. Amsterdam: Elsevier Science Publications.]
Venom toxicity varies among the different species, geographic locations, individual specimens, sexes, over the seasons, different milkings, and, of course, the method of injection (subcutaneous, intramuscular, or intravenous). Consequently, the values for ''Echis'' venoms differ significantly. In mice, the intravenous LD
50 ranges from 2.3 mg/kg (U.S. Navy, 1991) to 24.1 mg/kg (Christensen, 1955) to 0.44–0.48 mg/kg (Cloudsley-Thompson, 1988). In humans, the lethal dose is estimated to be up to 5 mg in some subspecies (Daniels, J. C. 2002). Venom from females was more than twice as toxic on average as venom from males.
The amount of venom produced also varies. Reported yields include 20–35 mg of dried venom from specimens 41–56 cm in length, 6–48 mg (16 mg average) from Iranian specimens and 13–35 mg of dried venom from animals from various other localities. Yield varies seasonally, as well as between the sexes: the most venom is produced during the summer months and males produce more than females.
Species
''*) Not including the nominate subspecies''
T)
Type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
Taxonomy
The taxonomy of the group was long confused, with a plethora of species of uncertain status. Several recent studies have clarified the diversity within the genus. This included the descriptions of ''E. omanensis'' and ''E. romani''.
A mitochondrial DNA phylogeny for the genus
demonstrated the distinctiveness of ''E. borkini'', ''E. jogeri'' and ''E. khosatzkii'', but showed ''E. multisquamatus'' to be a synonym of ''E. carinatus''.
References
Further reading
* Boquet P. 1967. "Pharmacology and toxicology of snake venoms of Europe and the Mediterranean regions". In: Bucherl W, editor. 1967. ''Venomous Animals and their Venoms. Vol. I.'' Paris: Masson. pp 340–58.
*
Boulenger GA. 1890. ''The Fauna of British India, Including Ceylon and Burma. Reptilia and Batrachia''. London: Secretary of State for India in Council. (Taylor & Francis, printers). xviii + 541 pp.
* Boulenger GA. 1896. ''Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the ... Viperidæ.'' London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xiv + 727 excrpp. + Plates I.- XXV. (Genus ''Echis'', p. 504).
* Cherlin, VA. 1990. Taxonomic revision of the snake genus ''Echis'' (Viperidae). II. An analysis of taxonomy and description of new forms. ''Proceedings of the Zoological Institute, Leningrad, USSR Academy of Schience'' 207: 193-223.
02 (in Russian).
* Christensen PA. 1955. ''South African Snake Venoms and Antivenins''. Johannesburg: South African Institute of Medical Research. 35 pp.
* Cloudsley-Thompson JL. 1988. The saw-scaled viper ''Echis carinatus''. ''British Herpetological Society Bulletin'' 24:32-33.
*
Gray JE. 1849. ''Catalogue of the Specimens of Snakes in the Collection of the British Museum.'' London: Trustees of the British Museum. (Edward Newman, printer). xv + 125 pp.
9
* Latifi M. 1991. ''The Snakes of Iran''. Second Edition. Oxford, Ohio: Published by the Department of the Environment and the Society for the Study of Amphibians and Reptiles. 156 pp. .
*
Merrem B. 1820. ''Versuch eines Systems der Amphibien. Tentamen Systematis Amphibiorum.'' Marburg: J.C. Krieger. xv + 191 pp. + 1 plate.
49
*
Minton SA Jr. 1967. "Snakebite". In: Beeson PB, McDermott W, editors. 1967. ''Cecil and Loeb Textbook of Medicine''. Philadelphia: Saunders. 420 pp.
* Minton SA Jr. 1974. ''Venom Diseases''. Springfield, Illinois: CC Thomas. 386 pp.
* U.S. Navy. 1991. ''Poisonous Snakes of the World''. United States Government. New York: Dover Publications Inc. 203 pp. .
External links
''Echis'' photo gallerya
Herpetology of Africa Accessed 9 September 2006.
*
Photograph of a bite to the leg inflicted by saw-scaled viper
{{Taxonbar, from=Q1478226
Viperinae
Snake genera
Taxa named by Blasius Merrem