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Viperidae

(Family)

Overview

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The Viperidae are a family of found all over the world, except in Australia, Ireland, Madagascar and the Arctic Circle. All have relatively long hinged fangs that permit deep penetration and injection of venom. Four subfamilies are currently recognized.2]

Description

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All viperids have a pair of relatively long solenoglyphous (hollow) fangs that are used to inject venom from glands located towards the rear of the upper jaws. Each of the two fangs is at the front of the mouth on a short maxillary bone that can rotate back and forth. When not in use, the fangs fold back against the roof of the mouth and are enclosed in a membranous sheath. The left and right fangs can be rotated together or independently. During a strike, the mouth can open nearly 180° a nd the maxilla rotates forward, erecting the fangs as late as possible so as the fangs do not become damaged. The jaws close on impact and powerful muscles that surround the venom glands contract to inject the venom as the fangs penetrate. This action is very fast; in defensive strikes it can be more a stab than a bite. Viperids use this mechanism primarily for immobilization and digestion of prey. Secondarily it is used for self-defense. Although in most cases with non prey items such as humans they are more likely to give a dry bite (not inject any venom).

Almost all vipers have keeled scales, a stocky build with a short tail, and, due to the location of the venom glands, a triangular-shaped head distinct from the neck. Their eyes have vertically elliptical, or slit-shaped, pupils that can open wide to cover most of the eye or close almost completely, which helps them to see in a wide range of light levels. Typically, vipers are nocturnal and ambush their prey.

Compared to many other snakes, vipers often appear rather sluggish. Most are ovoviviparous, giving birth to live young, but a few lay eggs; the word "viper" is derived from Latin vivo = "I live" and pario = "I give birth".[3]

Geographic Range

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Found in the Americas, Africa and Eurasia. In the Americas from southern Canada south through the United States, Mexico, Central America and into South America as far south as Argentina. Throughout Africa. In Eurasia from Spain, England and most of Scandinavia in the west, to within the Arctic Circle in the north, to the Sea of Okhotsk in the east, and to the Arabian Peninsula, India, and the Malay Peninsula and Archipelago in the south (including Java, Celebes an d the Philippines).[1] The Viperidae can be located on all continents except Antarctica and Australia.

Behaviour

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Experiments have shown that these snakes are capable of making decisions on how much venom to inject depending on the circumstances. In all cases, the most important determinant of venom expenditure is generally the size of the snake, with larger specimens being capable of delivering much more venom. The species is also important, since some are likely to inject more venom than others, may have much venom available, strike more accurately, or deliver a number of bites in a short space of time. In predatory bites, factors that influence the amount of venom injected include the size of the prey, the species of prey, and whether the prey item is held or released. The need to label prey for chemosensory relocation after a bite and release may also play a role. In defensive bites, the amount of venom injected may be determined by the size or species of the predator (or antagonist), as well as the assessed level of threat, although larger assailants and higher threat levels may not necessarily lead to larger amounts of venom being injected.[4]

Venom

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Viperid venoms typically contain an abundance of protein-degrading enzymes, called proteases, that produce symptoms such as pain, strong local swelling and necrosis, blood loss from cardiovascular damage complicated by coagulopathy, and disruption of the blood clotting system. Death is usually caused by collapse in blood pressure. This is in contrast to elapid venoms that generally contain neurotoxins that disable muscle contract ion and cause paralysis. Death from elapid bites usually results from asphyxiation because the diaphragm can no longer contract. However, this rule does not always apply: some elapid bites include proteolytic symptoms typical of viperid bites, while some viperid bites produce neurotoxic symptoms.[5]

Proteolytic venom is also dual-purpose: it is used for defense and to immobilize prey, as with neurotoxic venoms, and also many of the enzymes have a digestive function, breaking down molecules in prey items, such as lipids, nucleic acids, and proteins.[5] This is important, as many vipers have weak digestive systems.[6]

Due to the nature of proteolytic venom, a viperid bite is often a very painful experience and should always be taken seriously, even though it is not necessarily fatal. Even with prompt and proper treatment, a bite can still result in a permanent scar, and in the worst cases the affected limb may even have to be amputated. A victim's fate is impossible to predict as this depends on many factors, including (but not limited to) the species and size of the snake involved, how much venom was injected (if any), and the size and condition of the patient before being bitten. The patient may also be allergic to the venom and/or the antivenin.

Subfamilies

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Type genus = Vipera - Laurenti, 1768[1]

Taxonomy

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That Viperidae is attributed to Oppel (1811), as opposed to Laurenti (1768) or Gray (1825), is subject to some interpretation. However, the consensus among leading experts is that Laurenti used viperae as the plural of vipera (Latin for "viper", "adder", or "snake") and did not intend for it to indicate a family group taxon. Rather, it is attributed to Oppel, based on his Viperini as a distinct family group name, despite the fact that Gray was the first to use the form Viperinae.[1]

Photos

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Taxonomy

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The Family Viperidae is a member of the Superfamily Colubroidea. Here is the complete "parentage" of Viperidae:

The Family Viperidae is further organized into finer groupings including:

Genera

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Agkistrodon

Agkistrodon is a of venomous pit vipers found in North America from the United States south to northern Costa Rica. The name is derived from the Greek words ancistro, meaning "hook" and odon, which means "tooth", and is likely a reference to the fangs. Three species are currently recognized, all of them polytypic and closely related. [more]

Atheris

Atheris is a of venomous vipers found only found in tropical subsaharan Africa, excluding southern Africa. Confined to rain forest areas, many members have isolated and fragmented distributions. In an interesting example of convergent evolution, they show many similarities to the arboreal pit vipers of Asia and South America. Eight species are currently recognized. [more]

Atropoides

Atropoides is a of venomous pitvipers found in Mexico and Central America. Three species are currently recognized. The common names suggests they are able to leap at an attacker, but this is likely exaggerated. [more]

Azemiops

Azemiopinae is a subfamily created for the monotypic genus, Azemiops, that contains the venomous viper species A. feae, described here. No subspecies are recognized. The first specimens were described by European explorer M.L. Fea, with the genus later being described by Boulenger in 1888. Considered to be one of the most primitive vipers, it is found in the mountains of South East Asia in China, southeastern Tibet and Vietnam. [more]

Bitis

Bitis is a of venomous vipers found in Africa and the southern Arabian Peninsula. It includes the largest and the smallest vipers in the world. Members are known for their characteristic threat displays that involves inflating and deflating their bodies while hissing and puffing loudly. The type species for this genus is B. arietans, which is also the most widely distributed viper in Africa. Currently, 14 species are recognized. [more]

Bittis

Bitus

[more]

Bothriechis

Bothriechis is a of venomous pitvipers found predominantly in Mexico and Central America, although one species, B. schlegelii, ranges as far south as Colombia and Peru. All members are relatively slender and arboreal. The name Bothriechis is derived from the Greek words bothros and echis that mean "pit" and "viper" respectively. Seven species are currently recognized and no subspecies. [more]

Bothriopsis

A Genus in the Kingdom Animalia. [more]

Bothrocophias

Bothrocophias is a of venomous snakes in the Crotalinae subfamily of the Viperidae family. A relatively recently identified genus, it consists of four species and are native to northern South America. [more]

Bothrops

Bothrops is a of venomous pitvipers found in Central and South America. The generic name is derived from the Greek words bothros and ops that mean "pit" and "eye" or "face"; an allusion to the heat-sensitive loreal pit organs. Members of this genus are responsible for more human deaths in the Americas than any other group of venomous snakes. Currently, 32 species are recognized. [more]

Calloselasma

Calloselasma is a genus created for a venomous pitviper species, C. rhodostoma, which is found in Southeast Asia from Thailand to northern Malaysia and on the island of Java. No subspecies are currently recognized. [more]

Causus

The Causinae are a subfamily of venomous vipers found only in subsaharan Africa. It was created for the genus Causus; a group considered to be among the most primitive members of the family Viperidae based on head scalation, oviparity, venom apparatus and the fact that they have round pupils. However, this is contradicted by recent molecular studies. Six species are currently recognized. [more]

Cerastes

The cerastes (: ?e??st??, English: cerastes, English translation: "having horns") is a creature of Greek legend, a serpent that is incredibly flexible—so much so that it is said to have no spine. Cerastae can have either two large ram-like horns or four pairs of smaller horns. The cerastes hides its head in the sand with only the horns protruding out of the surface; this is meant to deceive other animals into thinking it is food. When the animal approaches the cerastes, the cerastes promptly kills it. [more]

Cerrophidion

Cerrophidion is a of venomous pitvipers that are found in southern Mexico, southward through the highlands of Central America to western Panama. The name is derived from the Spanish word cerro, which means "mountain", and the Greek word ophidion, which means "small snake." Four species are currently recognized and no subspecies. [more]

Cobra

Crotalus

Crotalus is a of venomous pitvipers found only in the Americas from southern Canada to northern Argentina. The name is derived from the Greek word krotalon, which means "rattle" or "castanet", and refers to the rattle on the end of the tail that make this group so distinctive. 29 species are currently recognized. [more]

Cryptelytrops

Daboia

Daboia is a genus created for a venomous viper species, D. russelii, which is found in Asia throughout the Indian subcontinent, much of Southeast Asia, southern China and Taiwan. Within much of its range, this species is easily the most dangerous viperid snake and a major cause of snakebite injury and mortality. It is a member of the big four venomous snakes in India, which are together responsible for nearly all Indian snakebite fatalities. The species was named in honor of Dr. Patrick Russell (1726 - 1805), who had earlier described this animal, and the genus after the Hindi name for it, which means "that lies hid", or "the lurker." Two subspecies are currently recognized, including the nominate subspecies described here. [more]

Deinagkistrodon

Deinagkistrodon is a genus created for a venomous pitviper species, D. acutus, found in Southeast Asia. No subspecies are currently recognized. [more]

Dienagkistrodon

Echis

Echis is a of venomous vipers found in the dry regions of Africa, the Middle East, Pakistan, India and Sri Lanka. These snakes are quick-tempered and strike readily, which, combined with a virulent hemotoxic venom, makes them very dangerous, despite their small size. They also have a characteristic threat display, rubbing sections of their body together to produce a "sizzling" warning sound. The name Echis is a Greek word that means "viper." Eight species are currently recognized. [more]

Eristicophis

Eristicophis is a genus created for a venomous viper species, E. macmahonii. It is found only in the desert region of Balochistan near the borders of Iran, Pakistan and Afghanistan. No subspecies are currently recognized. [more]

Garthius

Gloydius

Gloydius is a of venomous pitvipers found in Asia. Named after Howard Gloyd, this group is very similar to the North American genus Agkistrodon. Nine species are currently recognized. [more]

Hypnale

Hypnale is a of venomous pitvipers found in Sri Lanka and southwestern India. Three monotypic species are currently recognized (no subspecies). All members have a more or less upturned snouts that produce a hump-nosed effect. [more]

Lachesis

Lachesis can be: [more]

Macrovipera

Macrovipera is a of venomous vipers that inhabit the semideserts and steppes of North Africa, the Near and Middle East, and the Milos Archipelago in the Aegean Sea. These snakes are responsible for a number of bites in Africa and western Asia every year. They have a reputation for being ill-tempered and can inject a lot of venom, which is why they should be considered as very dangerous. Four species are currently recognized. [more]

Mesovipera

Montatheris

Montatheris is a genus created for a venomous viper species, M. hindii. This is a small terrestrial species found only at high altitude on Mount Kenya and the Aberdare mountain range in Kenya. No subspecies are currently recognized. [more]

Montivipera

Ophryacus

Ophryacus is a of venomous pitvipers endemic to Mexico. The name is derived from the Greek words ophrys and the suffix -acutus, which means "brow" and "belonging to"; an allusion to the characteristic hornlike scales over the eyes. Currently two species are recognized and no subspecies. [more]

Ovophis

Ovophis is a of venomous pitvipers found in Asia. Three species are currently recognized. [more]

Parias

Pelias

Peltopelor

Popeia

[more]

Porthidium

Porthidium is a of venomous pitvipers found in Mexico and southward to northern South America. The name is derived from the Greek words portheo and the suffix -idus, which means "destroy" and "having the nature of"; apparently a reference to the venom. Seven species are currently recognized. [more]

Proatheris

Proatheris is a genus created for a venomous viper species, P. superciliaris. This is a small terrestrial species found in Tanzania, Malawi and Mozambique. No subspecies are currently recognized. [more]

Protobothrops

Trimeresurus is a of venomous pitvipers found in Asia from Pakistan, through India, China, throughout Southeast Asia and the Pacific Islands. Currently 35 species are recognized. [more]

Pseudocerastes

Pseudocerastes is a genus created for a venomous viper species, P. persicus. This species is found throughout the Middle East and as far east as Pakistan, but not on the African mainland. Often referred to as the false horned viper because of the hornlike structures above their eyes that are made up of numerous small scales. This is in contrast to the "true" horned viper, Cerastes cerastes, that has similar supraorbital horns that consist of a single elongated scale. Two subspecies are currently recognized, including the nominate subspecies described here. [more]

Rhinaspis

Vipera is a of venomous vipers. It has a very wide range, being found from North Africa to just within the Arctic Circle and from Great Britain to Pacific Asia. The name is possibly derived from the Latin words vivus and pario, meaning "alive" and "bear" or "bring forth"; likely a reference to the fact that most vipers bear live young. Currently, 23 species are recognized. [more]

Sistrurus

Sistrurus is a of venomous pitvipers found in Canada, the United States and Mexico. The name is a Latinized form of the Greek word for "tail rattler" (Se?st??????, Seistrouros) and shares its root with the ancient Egyptian musical instrument, the sistrum, a type of rattle. Three species are currently recognized. [more]

Sisturus

Teleuraspis

Triceratolepidophis

Triceratolepidophis is a genus of venomous pit vipers. It contains only one species, T. sieversorum, commonly known as the three horned-scaled pit viper. Guo et al. (2007) synonymised this genus with the genus Protobothrops, based on evidence that T. sieversorum is phylogenetically nested within the existing species of that genus. [more]

Trigonocephalus

Trigonocephalus is a taxonomic synonym that may refer to: [more]

Trimeresurus

Trimeresurus is a of venomous pitvipers found in Asia from Pakistan, through India, China, throughout Southeast Asia and the Pacific Islands. Currently 35 species are recognized. [more]

Tropidolaemus

Tropidolaemus is a of venomous pitvipers found in southern India and Southeast Asia. Currently, two species are recognized and no subspecies. [more]

Vipera

Vipera is a of venomous vipers. It has a very wide range, being found from North Africa to just within the Arctic Circle and from Great Britain to Pacific Asia. The name is possibly derived from the Latin words vivus and pario, meaning "alive" and "bear" or "bring forth"; likely a reference to the fact that most vipers bear live young. Currently, 23 species are recognized. [more]

Viperidae

Viridovipera

Zhaoermia

Trimeresurus mangshanensis is a pitviper species endemic to Hunan province in China. It is reputed to be the only non-cobra known to spit venom. No subspecies are currently recognized. [more]

More info about the Genus Zhaoermia may be found here.

References

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  1. ^ a b c d e 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 Viperidae (TSN 174294). Integrated Taxonomic Information System. Retrieved on 10 August 2006.
  3. ^ Schuett GW, Höggren M, Douglas ME, Greene HW. 2002. Biology of the Vipers. Eagle Mountain Publishing, LC. 580 pp. 16 plates. ISBN 0-9720154-0-X.
  4. ^ Hayes WK, Herbert SS, Rehling GC, Gennaro JF. 2002. Factors that influence venom expenditure in viperids and other snake species during predatory and defensive contexts. In Schuett GW, Höggren M, Douglas ME, Greene HW. 2002. Biology of the Vipers. Eagle Mountain Publishing, LC. 580 pp. 16 plates. ISBN 0-9720154-0-X.
  5. ^ a b Slowinski J. 2000. Striking Beauties: Venomous Snakes at California Wild. Vol. 53:2. Accessed 2 December 2006.
  6. ^ S mith SA. 2004. Did Someone Say... SSSSnakes? at Maryland Dept. of Natural Resources. Accessed 2 December 2006.

Sources

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Last Revised: September 22, 2009
2009/09/22 14:12:02