Elapidae
| Elapidae | |
|---|---|
 | |
| Egyptian cobra, Naja haje | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Superfamily: | Colubroidea |
| Family: | Elapidae F. Boie, 1827 |
| Subfamilies | |
The Elapidae (Greek ἔλλοψ éllops, "sea-fish") [1] are a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America, and South America, and aquatically in the Pacific and Indian Oceans.
Elapid snakes exhibit a wide range of sizes, from 18-cm species of Drysdalia to the 5.6-m king cobra. All elapids are characterized by hollow, fixed fangs through which they inject venom. Currently, 325 species in 61 genera are recognized;[2] 58 genera and 251 species are in the Old World, against a minor diversity of three genera and 74 species in the New World.
Description
All elapids have a pair of proteroglyphous fangs used to inject venom from glands located towards the rear of the upper jaws. In outward appearance, terrestrial elapids look similar to the Colubridae: almost all have long and slender bodies with smooth scales, a head 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. Exceptions to all these generalizations occur: 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, and Vermicella) in either humid or arid environments. Some species have very generalised diets (euryophagy), but many taxa have narrow prey preferences (stenophagy) and correlated morphological specialisations, e.g. for feeding on other snakes, elongated burrowing lizards, squamate eggs, mammals, birds, frogs, fish, etc.
Sea snakes (the Hydrophiinae, sometimes considered to be a separate family) have adapted to a marine way of life in different ways and to various degrees. All have evolved paddle-like tails for swimming and the ability to excrete salt. Most also have laterally compressed bodies, their ventral scales are much reduced in size, their nostrils are located dorsally (no internasal scales), and they give birth to live young (ovoviviparous). In general, they have the ability to respire through their skin; experiments with the yellow-bellied sea snake, Pelamis platurus, have shown that this species can satisfy about 20% of its oxygen requirements in this manner, allowing for prolonged dives. The sea kraits (Laticauda spp.) are the sea snakes least adapted to aquatic life. They spend much of their time on land, where they lay their eggs. They have wide ventral scales, their tails are not as well-developed for swimming, and their nostrils are separated by internasal scales.
Dentition
The fangs, which are enlarged and hollow, are the first two teeth on each maxillary bone. Usually only one fang is in place on each side at any time. The maxilla is intermediate in both 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 and usually below the front edge of the eye and are angled backwards; some elapids (Acanthophis, Oxyuranus, Dendroaspis, and Ophiophagus) have long fangs on quite mobile maxillae and can make fast strikes.
A few species are capable of spraying their venom from forward-facing holes at the tips of their fangs using pressure, and this can act as a means of defense.
Distribution
On land, these snakes are found worldwide in tropical and subtropical regions, except in Europe. Sea snakes occur mainly in the Indian Ocean and the southwest Pacific. However, the range of one species, Pelamis platura, extends across the Pacific to the coasts of Central and South America.[3]
Venom
Many elapids are potentially deadly venomous snakes. Their venom is mainly neurotoxic, although many of them also possess several other types of toxins, including cardiotoxins and cytotoxins. This family has some members considered to be the world's most venomous land snakes based on the murine LD50 of their venom, such as the inland taipan.[4] Additionally, some large-sized elapids, such as the Asiatic king cobra, African black mamba, forest cobra, and Australasian coastal taipan, can inject a large quantity of venom during envenomation.
Elapids use their venom both to immobilize their prey and in self-defense.
Genera
| Genus[2] | Taxon author[2] |
Species[2] | Subspecies*[2] | Common name |
Geographic range[3] |
|---|---|---|---|---|---|
| Acalyptophis | Boulenger, 1869 | 1 | 0 | spiny-headed seasnake | Gulf of Thailand, South China Sea, the Strait of Taiwan, and the coasts of Guangdong, Indonesia, the Philippines, New Guinea, New Caledonia, Australia (Northern Territory, Queensland, Western Australia) |
| Acanthophis | Daudin, 1803 | 7 | 0 | death adders | Australia, New Guinea, Indonesia (Seram and Tanimbar) |
| Aipysurus | Lacépède, 1804 | 7 | 1 | olive sea snakes | Timor Sea, South China Sea, Gulf of Thailand, and coasts of Australia (Northern Territory, Queensland, Western Australia), New Caledonia, Loyalty Islands, southern New Guinea, Indonesia, western Malaysia and Vietnam |
| Aspidelaps | Fitzinger, 1843 | 2 | 4 | shieldnose cobras | South Africa (Cape Province, Transvaal), Namibia, southern Angola, Botswana, Zimbabwe, Mozambique |
| Aspidomorphus | Fitzinger, 1843 | 3 | 3 | collared adders | New Guinea |
| Astrotia | Fischer, 1855 | 1 | 0 | Stokes' 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, the Philippines |
| Austrelaps | Worrell, 1963 | 3 | 0 | copperheads | Australia (South Australia, New South Wales, Victoria, Tasmania) |
| Boulengerina | Dollo, 1886 | 2 | 1 | water cobras | Cameroon, Gabon, the Democratic Republic of the Congo, Congo, the 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, Taiwan, 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, the Philippines, Vietnam, Laos, southern China, Japan (Ryukyu Islands), Taiwan |
| Demansia | Gray, 1842 | 9 | 2 | whipsnakes | 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 | African or venomous garter snakes (not related to North American garter snakes, which are nonvenomous) | 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, the Democratic Republic of the Congo, Congo, Zambia, Kenya, north Burundi, Rwanda, Ethiopia, Uganda, Somalia |
| Emydocephalus | Krefft, 1869 | 2 | 0 | turtlehead sea snakes | The coasts of Timor (Indonesian Sea), New Caledonia, Australia (Northern Territory, Queensland, Western Australia), and in the Southeast Asian Sea along the coasts of China, Taiwan, Japan, and the Ryukyu Islands |
| Enhydrina | Gray, 1849 | 2 | 0 | beaked sea snakes | In the Persian Gulf (Oman, United Arab Emirates, etc.), south to the Seychelles and Madagascar,
Southeast Asian Sea (Pakistan, India, Bangladesh, Myanmar, Thailand, Vietnam), Australia (North Territory, Queensland), New Guinea and Papua New Guinea |
| Ephalophis | M.A. Smith, 1931 | 1 | 0 | Grey's mudsnake | Northwestern Australia |
| Furina | A.M.C. Duméril, 1853 | 5 | 0 | pale-naped snakes | Mainland Australia, southern New Guinea, Aru Islands |
| 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 | W. Peters, 1862 | 1 | 2 | Asian coral snakes | Taiwan, Japan (Ryukyu Islands) |
| Homoroselaps | Jan, 1858 | 2 | 0 | harlequin snakes | South Africa |
| 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 | Indoaustralian and Southeast Asian waters.[5] |
| Kerilia | Gray, 1849 | 1 | 0 | Jerdon's sea snake | Southeast Asian waters[5] |
| Kolpophis | M.A. Smith, 1926 | 1 | 0 | bighead sea snake | Indian Ocean[5] |
| Lapemis | Gray, 1835 | 1 | 1 | Shaw's sea snake | Persian Gulf to Indian Ocean, South China Sea, Indo-Australian archipelago and the western Pacific[5] |
| Laticauda | Laurenti, 1768 | 5 | 0 | sea kraits | Southeast Asian and Indo-Australian waters |
| Leptomicrurus | K.P. Schmidt, 1937 | 4 | 2 | blackback coral snake | Northern South America |
| Loveridgelaps | McDowell, 1970 | 1 | 0 | Solomons small-eyed snake | Solomon Islands |
| Micropechis | Boulenger, 1896 | 1 | 0 | New Guinea small-eyed snake | New Guinea |
| Micruroides | K.P. Schmidt, 1928 | 1 | 2 | Western coral snakes | USA (Arizona, southwestern New Mexico), Mexico (Sonora, Sinaloa) |
| Micrurus | Wagler, 1824 | 69 | 54 | coral snakes | Southern North America, South America |
| Naja | Laurenti, 1768 | 23 | 3 | cobras | Africa, Asia |
| Notechis | Boulenger, 1896 | 2 | 0 | tiger snakes | Southern Australia, including many offshore islands |
| Ogmodon | W. Peters, 1864 | 1 | 0 | bola | Fiji |
| Ophiophagus | Günther, 1864 | 1 | 0 | king cobra | Bangladesh, Myanmar, Cambodia, China, India, Andaman Islands, Indonesia, Laos, Thailand, Vietnam, western Malaysia, the Philippines, Sri Lanka |
| Oxyuranus | Kinghorn, 1923 | 3 | 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 | viperine sea snake | Persian Gulf, Indian Ocean, South Chinese Sea northeast to coastal region of Fujian and Strait of Taiwan |
| Pseudechis | Wagler, 1830 | 7 | 0 | black snakes (and king brown) | Australia |
| Pseudohaje | Günther, 1858 | 2 | 0 | tree 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 | F. 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 |
| Suta | Worrell, 1961 | 10 | 2 | hooded snakes (and curl snake) | Australia |
| Thalassophis | P. Schmidt, 1852 | 1 | 0 | anomalous sea snake | South Chinese Sea (Malaysia, Gulf of Thailand), Indian Ocean (Sumatra, Java, Borneo) |
| Toxicocalamus | Boulenger, 1896 | 11 | 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 | Australia |
| Walterinnesia | Lataste, 1887 | 2[6] | 0 | black desert cobra | Egypt, Israel, Lebanon, Syria, Jordan, Iraq, Iran, Kuwait, Saudi Arabia, Turkey [7] |
* Not including the nominate subspecies
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. Good molecular evidence via karyotyping, protein electrophoretic analysis, immunological distance, DNA sequence analysis, and so on, suggests reciprocal monophyly of two groups:
- African, Asian, and New World Elapinae
- Australasian and marine Hydrophiinae
Thus, the Australian terrestrial elapids are technically 'hydrophiines', although they are not sea snakes. It is believed that the Laticauda and the 'true sea snakes' evolved separately from Australasian land snakes. Asian cobras, coral snakes, and American coral snakes also appear to be monophyletic, while African cobras do not.[8][9]
The type genus for the Elapidae was originally Elaps, but the group was moved to another family. In contrast to what is typical of 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 shouldhave been assigned to the Atractaspididae.
See also
- Elapidae by common name
- Elapidae by taxonomic synonyms
- List of snakes, overview of all snake families and genera
References
 |
Wikimedia Commons has media related to Elapidae. |
- ↑ "Definition of 'elapid'.". dictionary.com. Retrieved 2009-07-13.
- 1 2 3 4 5 "Elapidae". Integrated Taxonomic Information System. Retrieved 27 November 2006.
- 1 2 Elapidae at the Reptarium.cz Reptile Database. Accessed 3 November 2008.
- ↑ WCH Clinical Toxinology Resources: Oxyuranus microlepidotus
- 1 2 3 4 The Hydrophiidae at Cyberlizard's home pages. Accessed [12 August] [2007].
- ↑ Nilson, G. & N. Rastegar-Pouyani (2007) Walterinnesia aegyptia Lataste, 1887 (Ophidia: Elapidae) and the status of Naja morgani Mocquard 1905. Russian Journal of Herpetology, 14: 7-14.
- ↑ Ugurtas, I. H., T. J. Papenfuss and N. L. Orlov. 2001. New record of Walterinnesia aegyptia Lataste, 1887 (Ophidia: Elapidae: Bungarinae) in Turkey. Russian Journal of Herpetology. 8(3):239-245.
- ↑ Slowinski, J. B. and Keogh J. S. (April 2000). "Phylogenetic Relationships of Elapid Snakes Based on Cytochrome b mtDNA Sequences". Molecular Phylogenetics and Evolution. 15 (1): 157–64. doi:10.1006/mpev.1999.0725. PMID 10764543.
- ↑ Williams D; Wuster W; Fry B. G (July 2006). "The good, the bad and the ugly: Australian snake taxonomist and a history of the taxonomy of Australia's venomous snakes" (PDF). Toxicon. 48 (1): 919–30. doi:10.1016/j.toxicon.2006.07.016. PMID 16999982.