Elapidae

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Elapidae

Egyptian cobra, Naja haje

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Elapidae Boie, 1827

The Elapidae, or elapids, are a family of venomous snakes found in tropical and subtropical regions around the world, including the Indian Ocean and the Pacific. They are characterized by possessing a set of hollow, fixed fangs through which they inject venom, and come in a wide range of sizes, from only 18 cm (Drysdalia) up to 6 m in length (Ophiophagus). Currently, 61 genera that include 231 species are recognized.^[1]

1 Description
2 Venom
3 Genera
4 Taxonomy
5 Cited references
6 External links

[edit] Description

Outwardly, terrestrial elapids look similar to the colubridae: almost all have long and slender bodies with smooth scales, a head that is covered with large shields and not always distinct from the neck, and eyes with round pupils. In addition, their behavior is usually quite active and most are oviparous. There are exceptions to all these generalizations: e.g. the death adders (Acanthophis) include short and fat, rough-scaled, very broad-headed, cat-eyed, live-bearing, sluggish ambush predators with partly fragmented head shields.

Some elapids are strongly arboreal (African Pseudohaje and Dendroaspis, Australian Hoplocephalus), while many others are more or less specialised burrowers (e.g. Ogmodon, Parapistocalamus, Simoselaps, Toxicocalamus, Vermicella) in either humid or arid environments. Some species have very generalised diets but many taxa have narrow prey preferences and correlated morphological specialisations, e.g. for feeding on other snakes, elongate burrowing lizards, squamate eggs, mammals, birds, frogs, fish, etc.

Sea snakes, which are also elapids, have adapted to a marine way of life in different ways and to various degrees. Characteristics can include laterally compressed bodies, rudder-like tails for swimming, the ability to excrete salt and give birth to live young (ovoviviparous). Some genera, including Hydrophis, have ventral scales that are much reduced in size. Others, like the olive sea snakes (Aipysurus sp.) can absorb oxygen from the surrounding water directly through their skin and may obtain 10-22% in this manner. The sea kraits (Laticauda sp.), seem to be the least well-adapted to an aquatic life, having wide ventral scales, a poorly developed tail fin and needing to return to land in order to mate and lay eggs (oviparous).

All elapids have a pair of proteroglyphous fangs that are used to inject venom from glands located towards the rear of the upper jaws. The fangs are the first two teeth on each maxillary bone, which are enlarged and hollow, and usually only one is in place on each side at any time (see alternate tooth replacement). The maxilla is intermediate in length and mobility between typical colubrids (long, less mobile) and viperids (very short, highly mobile). When the mouth is closed, the fangs fit into grooved slots in the buccal floor; in the longest-fanged elapids (e.g. Acanthophis, Oxyuranus) it is common for the fangs to pierce right through the intermandibular skin, which does not seem to endanger the snake. The fangs are usually below the front edge of the eye and are angled backwards; due to this construction, most elapids must actually bite in order to envenomate. This action is therefore not as quick as with the viperids, that can envenomate with only a quick, stabbing motion. Some elapids (Acanthophis, Oxyuranus, and especially Dendroaspis) have long fangs on quite mobile maxillae (the prefrontal and ectopterygoid contacts are nearly as close together as in viperids), and can therefore make very fast stabbing strikes like viperids. Elapids use their venom both to immobilize their prey and in self-defense.

[edit] Venom

All elapids are venomous and many are potentially deadly. The venoms are mostly neurotoxic and are considered more dangerous than the mainly proteolytic viper venoms. Members include the black mamba (Dendroaspis polylepis), a species many regard as the world's most dangerous snake, the fierce snake (Oxyuranus microlepidotus), which is the most venomous land snake, and Hydrophis belcheri, a sea snake and the most toxic venom of all snakes.

[edit] Genera

Genus^[1]	Authority^[1]	Species^[1]	Subsp.*^[1]	Common name	Geographic range
Acalyptophis	Boulenger, 1869	1	0	Spiny-headed seasnake	Gulf of Thailand, South China sea, coast of Guangdong and Strait of Taiwan, Indonesia, Philippines, New Guinea, New Caledonia, Australia (Northern Territory, Queensland, Western Australia)
Acanthophis	Daudin, 1803	7	0	Death adders	Australia, New Guinea, Indonesia (Seram, Tanimbar)
Aipysurus	Lacépède, 1804	7	1	Olive sea snakes	Timor Sea, South China Sea, Gulf of Thailand, coast of Australia (North Territory, Queensland, West Australia), New Caledonia, Loyalty Islands, southern New Guinea, Indonesia, western Malaysia, Vietnam
Aspidelaps	Fitzinger, 1843	2	4	Shieldnose cobras	South Africa (Cape Province, Transvaal), Namibia, southern Angola, Botswana, Zimbabwe,Mozambique
Aspidomorphus	Fitzinger, 1843	3	0		New Guinea
Astrotia	Fischer, 1855	1	0	Stoke's sea snake	Coastal areas from west India and Sri Lanka through Gulf of Thailand to China Sea, west Malaysia, Indonesia east to New Guinea, north and east coasts of Australia, Philippines
Austrelaps	Worrell, 1963	3	0	Australian Copperheads	Australia (South Australia, New South Wales, Victoria, Tasmania)
Boulengerina	Dollo, 1886	2	1	Water cobras	Cameroon, Gabon, Democratic Republic of the Congo, Congo, Central African Republic, Tanzania, Equatorial Guinea, Rwanda, Burundi, Zambia
Bungarus	Daudin, 1803	12	4	Kraits	India (incl. Andaman Island), Myanmar, Nepal, Vietnam, Afghanistan, Pakistan, Sri Lanka, Bangladesh, Cambodia, Indonesia (Java, Sumatra, Bali, Sulawesi), Peninsular Malaysia, Singapore, Thailand
Cacophis	Günther, 1863	4	0	Rainforest crowned snakes	Australia (New South Wales, Queensland)
Calliophis	Gray, 1834	8	11	Oriental coral snakes	India, Bangladesh, Sri Lanka, Nepal, Indonesia, Cambodia, Malaysia, Singapore, Thailand, Burma, Brunei, Philippines, Vietnam, Laos, southern China, Japan (Ryukyu Islands), Taiwan
Demansia	Gray, 1842	9	2	Venomous whip snakes	New Guinea, continental Australia
Dendroaspis	Schlegel, 1848	4	1	Mambas	Kenya, Tanzania, Mozambique, Malawi, Zimbabwe, South Africa, Ghana, Togo, Benin, Nigeria, Cameroon, Guinea, Gabon, Principe (Gulf of Guinea), Central African Republic, Democratic Republic of the Congo, Congo, Uganda, Rwanda, Burundi, Equatorial Guinea, Angola, Sudan, Botswana, Burkina Faso, Eritrea, Senegal, Mali, Ethiopia, Ivory Coast, Namibia, Somalia, Swaziland, Zambia, Gambia, Guinea Bissau, Liberia, Ivory Coast, Sierra Leone
Denisonia	Krefft, 1869	2	0	Ornamental snakes	Central Queensland and central northern New South Wales, Australia
Drysdalia	Worrell, 1961	3	0	Southeastern grass snakes	Southern Australia (Western Australia, South Australia, Victoria, Tasmania, New South Wales)
Echiopsis	Fitzinger, 1843	1	0	Bardick	Southern Australia (Western Australia, South Australia, Victoria, New South Wales)
Elapognathus	Boulenger, 1896	2	0	Southwestern grass snakes	Western Australia
Elapsoidea	Bocage, 1866	10	7	Venomous garter snakes	Senegal, South Africa, Mozambique, Namibia, Botswana, Zimbabwe, Swaziland, Gambia, Angola, Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Ghana, Ivory Coast, Malawi, Mali, Mauritania, Niger, Nigeria, Uganda, Senegal, Sudan, Tanzania, Togo, Democratic Republic of the Congo, Congo, Zambia, Kenya, north Burundi, Rwanda, Ethiopia, Uganda, Somalia
Emydocephalus	Krefft, 1869	2	0	Turtlehead sea snakes
Enhydrina	Gray, 1849	2	0	Beaked sea snakes
Ephalophis	M.A. Smith, 1931	1	0	Grey's mudsnake	North-western Australia
Furina	Duméril, 1853	3	0	Pale-naped snakes	Mainland Australia
Glyphodon	Günther, 1858	2	0	Brown-headed snakes	Australia (Queensland), New Guinea
Hemachatus	Fleming, 1822	1	0	Spitting cobra	South Africa, Zimbabwe, Lesotho, Swaziland
Hemiaspis	Fitzinger, 1861	2	0	Swamp snakes	Eastern Australia (New South Wales, Queensland)
Hemibungarus	Peters, 1862	1	2	Asian coral snakes	Taiwan, Japan (Ryukyu Islands)
Homoroselaps	Jan, 1858	2	0	Harlequin snakes
Hoplocephalus	Wagler, 1830	3	0	Broad-headed snakes	Eastern Australia (New South Wales, Queensland)
Hydrelaps	Boulenger, 1896	1	0	Port Darwin mudsnake	Northern Australia, southern New Guinea
Hydrophis	Latreille In Sonnini & Latreille, 1801	34	3	Sea snakes
Kerilia	Gray, 1849	1	0	Jerdon's sea snake
Kolpophis	M.A. Smith, 1926	1	0	Bighead sea snake
Lapemis	Gray, 1835	1	1	Shaw's sea snake
Laticauda	Laurenti, 1768	5	0	Sea kraits
Leptomicrurus	Schmidt, 1937	4	2	Blackback Coral Snake
Loveridgelaps	McDowell, 1970	1	0	Solomons small-eyed snake	Solomon Islands
Micropechis	Boulenger, 1896	1	0	New Guinea small-eyed snake	New Guinea
Micruroides	Schmidt, 1928	1	2	Western coral snakes	USA (Arizona, SW New Mexico), Mexico (Sonora, Sinaloa)
Micrurus	Wagler, 1824	69	54	Coral snakes	southern North America, South America
Naja	Laurenti, 1768	20	5	Cobras	Africa, Asia
Notechis	Boulenger, 1896	2	0	Tiger snakes	Southern Australia, including many offshore islands
Ogmodon	Peters, 1864	1	0	Bola	Fiji
Ophiophagus	Günther, 1864	1	0	King cobra	Bangladesh, Myanmar, Cambodia, China, India, Andaman Islands, Indonesia, Laos, Thailand, Vietnam, west Malaysia, Philippines
Oxyuranus	Kinghorn, 1923	2	2	Taipans	Australia, New Guinea
Parahydrophis	Burger & Natsuno, 1974	1	0	Northern mangrove sea snake	Northern Australia, southern New Guinea
Paranaja	Loveridge, 1944	1	2	Many-banded snakes	West/central Democratic Republic of the Congo, Congo, Cameroon
Parapistocalamus	Roux, 1934	1	0	Hediger's snake	Bougainville Island, Solomons
Paroplocephalus	Keogh, Scott and Scanlon, 2000	1	0	Lake Cronin snake	Western Australia
Pelamis	Daudin, 1803	1	0	Yellow-bellied sea snake	Indian and Pacific Oceans
Praescutata	Wall, 1921	1	0
Pseudechis	Wagler, 1830	7	0	Black snakes (and king brown)	Australia
Pseudohaje	Günther, 1858	2	0	Forest cobras	Angola, Burundi, Cameroon, Central African Republic, Democratic Republic of the Congo, Congo, Gabon, Ghana, Kenya, Nigeria, Rwanda, Uganda, Sierra Leone, Liberia, Ivory Coast, Togo, Nigeria
Pseudonaja	Günther, 1858	8	2	Venomous brown snakes (and dugites)	Australia
Rhinoplocephalus	Müller, 1885	6	0	Australian Small-eyed snakes	Southern and eastern Australia, southern New Guinea
Salomonelaps	McDowell, 1970	1	0	Solomons coral snake	Solomon Islands
Simoselaps	Jan, 1859	13	3	Australian coral snakes	Mainland Australia
Sinomicrurus	Slowinski et al., 2001	5	4
Suta	Worrell, 1961	10	2	Hooded snakes (and Curl Snake)	Australia
Thalassophis	P. Schmidt, 1852	1	0	Anomalous sea snake
Toxicocalamus	Boulenger, 1896	9	0	New Guinea Forest snakes	New Guinea (and nearby islands)
Tropidechis	Günther, 1863	2	0	Rough-scaled snake	Eastern Australia
Vermicella	Gray In Günther, 1858	5	0	Bandy-bandies
Walterinnesia	Lataste, 1887	1	0	Black desert cobra	Egypt, Israel, Lebanon, Syria, Jordan, Iraq, Iran, Kuwait, Saudi Arabia

*) Not including the nominate subspecies (typical form).

[edit] Taxonomy

The table above lists all of the elapid genera and no subfamilies. In the past, many subfamilies were recognized, or have been suggested for the Elapidae, including the Elapinae, Hydrophiinae (sea snakes), Micrurinae (coral snakes), Acanthophiinae (Australian elapids) and the Laticaudinae (sea kraits). Currently, none are universally recognized. There is now good molecular evidence for reciprocal monophyly of two groups: the African, Asian and New World Elapinae, and Australasian and marine Hydrophiinae. Thus Australian terrestrial elapids are 'hydrophiines', though not sea snakes; Laticauda and the 'true sea snakes' evolved separately from among the Australasian land-snakes.

The type genus for the Elapidae was originally Elaps, but that group was moved to another family. In contrast to what usually happens in botany, the Elapidae family was not renamed. In the meantime, Elaps was renamed Homoroselaps and moved back to the Elapidae. However, Nagy et al. 2005 regard it as a sister taxon to Atractaspis which should therefore have been assigned to the Atractaspididae.