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Naja is a genus of venomous elapid snakes. Although several other genera share the common name, Naja species are the most recognized and most widespread group of snakes commonly known as cobras. The genus Naja consists of 20 to 22 species, but has undergone several taxonomic revisions in recent years, so sources vary greatly.[1] They range throughout Africa, Southwest Asia, South Asia and Southeast Asia. The most recent revison .[2] listed 28 species after the synonymisation of Boulengerina and Paranaja with Naja
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Etymology [edit]
The origin of this genus name is from the Old Indic nāga, cognate with English 'snake', Germanic: *snēk-a-, Proto-IE: *(s)nēg-o-.[3]
Description [edit]
Different Naja species vary in length and most are relatively slender-bodied snakes. Most species are capable of attaining lengths of 1.84 m (6.0 ft). Maximum lengths for some of the larger species of cobra are around 3.1 m (10 ft), with the forest cobra arguably being the longest species.[4] All have a characteristic ability to raise the front quarters of their bodies off the ground and flatten their necks to appear larger to a potential predator.
Venom [edit]
All species in the genus Naja are capable of delivering a fatal bite to a human. Most species have strongly neurotoxic venom, which attacks the nervous system, causing paralysis, but many also have cytotoxic features which causes swelling and necrosis, and has a significant anticoagulant effect. Some also have cardiotoxic components to their venom.
Several Naja species, referred to as spitting cobras, have a specialized venom delivery mechanism, in which their front fangs, instead of releasing venom through the tips (similar to a hypodermic needle), have a rifled opening in the front surface which allows the snake to propel the venom out of the mouth. While typically referred to as "spitting", the action is more like squirting. The range and accuracy with which they can shoot their venom varies from species to species, but it is used primarily as a defense mechanism. Once sprayed onto a victim's skin, the venom acts as a severe irritant. If it is introduced to the eye, it can cause a severe burning sensation and temporary or even permanent blindness if not cleaned out immediately and thoroughly.
Murine subcutaneous LD50 values for some cobra species include 0.20 mg/kg for N. philippinensis (Philippine cobra), which is considered to be the most venomous species, 0.29[5]—0.53 mg/kg[6] for N. atra (Chinese cobra), 0.40 mg/kg for N. oxiana (Caspian cobra), 0.45[5]—0.80 mg/kg[7] for N. naja (Indian cobra), 0.72 mg/kg for N. nivea (Cape cobra),[5] 1.15 mg/kg for N. haje (Egyptian cobra) and 2.0 mg/kg for Naja nigricollis (black-necked spitting cobra).[6]
Some murine IV LD50 values include 0.29 mg/kg for N. melanoleuca (forest cobra), 0.345 mg/kg for N. atra (Chinese cobra), 0.373 mg/kg for N. kaouthia (monocled cobra), and 0.96 mg/kg for N. oxiana (Caspian cobra).[5]
The murine IP LD50 of N. annulata (banded water cobra) and N. christyi (Congo water cobra) venoms were 0.143 and 0.120 mg/kg, respectively.[8] Other IP LD50 values include N. haje (Egyptian cobra) at 0.185 mg/kg, N. kaouthia (monocled cobra) at 0.225 mg/kg, N. naja at 0.315 mg/kg, N. melanoleuca at 0.324 mg/kg, N. nivea (Cape cobra) at 0.4 mg/kg, N. nigricollis at 0.4 mg/kg, and N. pallida (red spitting cobra) at 2.0 mg/kg.[5]
Species [edit]
| Species[1] | Authority[1] | Subsp.*[1] | Common name | Geographic range |
|---|---|---|---|---|
| N. anchietae | Bocage, 1879 | 0 | Anchieta's cobra (Angolan Cobra) | Angola, Botswana, Namibia, Zambia, eastern Zimbabwe |
| N. annulata | (Buchholz and Peters, 1876) | 1 | Banded water cobra | Cameroon, Central African Republic, Democratic Republic of Congo, Republic of Congo, Equatorial Guinea, Gabon, Rwanda, and the province of Cabinda in Angola |
| N. annulifera | Peters, 1854 | 0 | Snouted cobra | Botswana, Malawi, Mozambique, South Africa, Swaziland, Zambia, Zimbabwe |
| N. arabica | Scortecci, 1932 | 0 | Arabian cobra | Oman, Saudi Arabia, Yemen |
| N. ashei | Wüster and Broadley, 2007 | 0 | Ashe's spitting cobra (giant spitting cobra) | Southern Ethiopia, Kenya, Somalia, eastern Uganda |
| N. atra | Cantor, 1842 | 0 | Chinese cobra | Southern China, northern Laos, Taiwan, northern Vietnam |
| N. christyi | (Boulenger, 1904) | 0 | Congo water cobra | Democratic Republic of Congo, Republic of Congo, and in the province of Cabinda in Angola |
| N. haje | (Linnaeus, 1758) | Egyptian cobra | Algeria, Burkina Faso, Cameroon, Central African Republic, northern Democratic Republic of the Congo, Chad, Egypt, Eritrea, Ethiopia, Kenya, Libya, Mali, Mauritania, Morocco, Niger, Nigeria, Somalia, Sudan, Tanzania, Togo, Tunisia, Uganda, Western Sahara | |
| N. kaouthia | Lesson, 1831 | 0 | Monocled cobra | Bangladesh, Bhutan, Burma, Cambodia, southern China, eastern India, Laos, northwestern Malaysia, Nepal, Thailand, southeastern Tibet, Vietnam |
| N. katiensis | Angel, 1922 | 0 | Mali cobra | Benin, Burkina Faso, Cameroon, Ghana, Guinea, Ivory Coast, Mali, Gambia, Mauritania, Niger, Nigeria, Senegal, Togo |
| N. mandalayensis | Slowinski & Wüster, 2000 | 0 | Mandalay spitting cobra (Burmese spitting cobra) | Burma |
| N. melanoleuca | Hallowell, 1857 | 0 | Forest cobra | Angola, Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Democratic Republic of the Congo (Zaire), Congo, Ethiopia, Gabon, Ghana, Gambia, Guinea, Guinea Bissau, Ivory Coast, Kenya, Liberia, Malawi, Mali, Mozambique, Niger, Nigeria, Rwanda, Sao Tom`e, Senegal, Sierra Leone, Somalia, South Africa, Sudan, Tanzania, Togo, Uganda, Zambia, Zimbabwe |
| N. mossambica | Peters, 1854 | 0 | Mozambique spitting cobra | Extreme southeastern Angola, Botswana, Malawi, Mozambique, Somalia, northeastern Namibia, South Africa, Swaziland, Tanzania (including Pemba Island), Zambia, Zimbabwe |
| N. multifasciata | Werner, 1902 | 0 | Burrowing cobra | Cameroon, Congo, Democratic Republic of the Congo (Zaire), Gabon |
| N. naja | (Linnaeus, 1758) | 0 | Indian cobra (spectacled cobra) | Bangladesh, Bhutan, India, Nepal, Pakistan, Sri Lanka |
| N. nigricincta | Bogert, 1940 | 1 | Zebra spitting cobra | Angola, Namibia, South Africa |
| N. nigricollis | Reinhardt, 1843 | 0 | Black-necked spitting cobra | Angola, Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Democratic Republic of the Congo (except in the center), Congo, Ethiopia, Gabon, Gambia, Ghana, Guinea Bissau, Guinea, Ivory Coast, Kenya, Liberia, Mali, Mauritania, Namibia, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, Sudan, Tanzania, Somalia, Togo, Uganda, Zambia |
| N. nivea | (Linnaeus, 1758) | 0 | Cape cobra (yellow cobra) | Botswana, Lesotho, Namibia, South Africa |
| N. nubiae | Wüster & Broadley, 2003 | 0 | Nubian spitting cobra | Chad, Egypt, Eritrea, Niger, Sudan |
| N. oxiana | (Eichwald, 1831) | 0 | Caspian cobra | Afghanistan, northwest India, Iran, Kyrgyzstan, Pakistan, Tajikistan, Turkmenistan, Uzbekistan |
| N. pallida | Boulenger, 1896 | 0 | Red spitting cobra | Djibouti, Ethiopia, Kenya, Somalia, Tanzania |
| N. philippinensis | Taylor, 1922 | 0 | Philippine cobra | Philippines (Luzon, Mindoro) |
| N. sagittifera | Wall, 1913 | 0 | Andaman cobra | India (Andaman Islands) |
| N. samarensis | Peters, 1861 | 0 | Peters' cobra | Philippines (Mindanao, Bohol, Leyte, Samar, Camiguin) |
| N. senegalensis | Trape, Chirio & Wüster, 2009 | 0 | Senegalese cobra | Benin, Burkina Faso, Ghana, Guinea, Mali, Niger, Nigeria, Senegal |
| N. siamensis | Laurenti, 1768 | 0 | Indo-Chinese spitting cobra | Cambodia, Laos, Thailand, Vietnam |
| N. sputatrix | F. Boie, 1827 | 0 | Javan spitting cobra | Indonesia (Java, Lesser Sunda Islands, East Timor) |
| N. sumatrana | Müller, 1887 | 0 | Equatorial spitting cobra | Brunei, Indonesia (Sumatra, Borneo, Bangka, Belitung), Malaysia, Philippines (Palawan), southern Thailand, Singapore |
*) Not including the nominate subspecies.
T) Type species.[9]
King cobra [edit]
Despite its popular name, the king cobra (Ophiophagus hannah) is not considered a member of the genus Naja.
Taxonomy [edit]
The genus contains several species complexes of closely related and often similar species, some of them only recently described or defined. Several recent taxonomic studies have revealed species not included in the current listing in ITIS:[1]
- Naja anchietae (Bocage, 1879), or Anchieta's cobra, is regarded as a subspecies of N. haje by Mertens (1937) and of N. annulifera by Broadley (1995). It is regarded as a full species by Broadley and Wüster (2004).[10][11]
- Naja arabica Scortecci, 1932, the Arabian cobra, has long been considered a subspecies of N. haje, but was recently raised to the status of species.[12]
- Naja ashei Broadley and Wüster, 2007, Ashe’s spitting cobra, is a newly described species found in Africa.[13][14]
- Naja nigricincta Bogert, 1940, was long regarded as a subspecies of N. nigricollis, but was recently found to be a full species (with N. n. woodi as a subspecies).[15][16]
- Naja senegalensis Trape et al., 2009, is a new species encompassing what were previously considered to be the West African savanna populations of N. haje.[12]
Two recent molecular phylogenetic studies have also supported the incorporation of the species normally assigned to the genera Boulengerina and Paranaja into Naja, as both are closely related to the forest cobra (Naja melanoleuca) [15][17]
Wallach et al.[2] suggested recognition of four subgenera within Naja: Naja for the Asiatic cobras, Boulengerina for the African forest, water and burrowing cobras, Uraeus for the Egyptian and Cape cobra group and Afronaja for the African spitting cobras.
References [edit]
- ^ a b c d e "Naja". Integrated Taxonomic Information System. Retrieved 13 April 2008.
- ^ a b Wallach, Van; Wüster, W; Broadley, Donald G. (2009). "In praise of subgenera: taxonomic status of cobras of the genus Naja Laurenti (Serpentes: Elapidae)". Zootaxa 2236 (1): 26–36.
- ^ Proto-IE: *(s)nēg-o-, Meaning: snake, Old Indian: nāgá- m. 'snake', Germanic: *snēk-a- m., *snak-an- m., *snak-ō f.; *snak-a- vb. http://starling.rinet.ru/cgi-bin/response.cgi?single=1&basename=/data/ie/piet&text_number=2649&root=config
- ^ "Naja melanoleuca - General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid, Antivenoms". WCH Clinical Toxinology Resource. University of Queensland. Retrieved 17 December 2011.
- ^ a b c d e "LD50". Séan Thomas & Eugene Griessel - Dec 1999;Australian Venom and Toxin database. University of Queensland. Retrieved 1 December 2011.
- ^ a b Snakes of medical importance. Singapore: Venom and toxic research group. p. 253. ISBN 9971-62-217-3.
- ^ Brown Ph.D, John H. (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, IL USA: Charles C. Thomas Publishers. pp. 81–82. ISBN 0-398-02808-7.
- ^ Weinstein, Scott A.; James J. Schmidt, Leonard A. Smith (30). Toxicon 29 (11): 1315–1327. PMID 1814007 http://www.ncbi.nlm.nih.gov/pubmed/1814007
|url=missing title (help). Retrieved 24 April 2012. - ^ Zhao E, Adler K. 1993. Herpetology of China. Society for the Study of Amphibians and Reptiles. 522 pp. LCCN 92-61941. ISBN 0-916984.
- ^ Broadley, D.G. & W. Wüster (2004) A review of the southern African ‘non-spitting’ cobras (Serpentes: Elapidae: Naja). African Journal of Herpetology 53:101-122.
- ^ Naja anchietae at the Reptarium.cz Reptile Database. Accessed 13 April 2007.
- ^ a b Trape, J.-F., L. Chirio, D.G. Broadley & W. Wüster (2009) Phylogeography and systematic revision of the Egyptian cobra (Serpentes: Elapidae: Naja haje) species complex, with the description of a new species from West Africa. Zootaxa 2236: 1-25.
- ^ Wüster, W. & D.G. Broadley (2007) Get an eyeful of this: a new species of giant spitting cobra from eastern and north-eastern Africa (Squamata: Serpentes: Elapidae: Naja). Zootaxa 1532: 51-68
- ^ Naja ashei at the Reptarium.cz Reptile Database. Accessed 13 April 2007.
- ^ a b Wüster, W., S. Crookes, I. Ineich, Y. Mane, C.E. Pook, J.-F. Trape & D.G.Broadley (2007) The phylogeny of cobras inferred from mitochondrial DNA sequences: evolution of venom spitting and the phylogeography of the African spitting cobras (Serpentes: Elapidae: Naja nigricollis complex). Molecular Phylogenetics and Evolution, 45: 437-453.
- ^ Naja nigricincta at the Reptarium.cz Reptile Database. Accessed 29 December 2008.
- ^ Nagy, Z.T., Vidal, N., Vences, M., Branch, W.R., Pauwels, O.S.G., Wink, M., Joger, U., 2005. Molecular systematics of African Colubroidea (Squamata: Serpentes). In: Huber, B.A., Sinclair, B.J., Lampe, K.-H. (Eds.), African Biodiversity: Molecules, Organisms, Ecosystems. Museum Koenig, Bonn, pp. 221–228.
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