Jameson's mamba
Jameson's mamba | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Serpentes |
Family: | Elapidae |
Genus: | Dendroaspis |
Species: | D. jamesoni
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Binomial name | |
Dendroaspis jamesoni | |
Range of Jameson's mamba | |
Synonyms[3] | |
Jameson's mamba (Dendroaspis jamesoni) is a species of highly venomous snake native to equatorial Africa. A member of the mamba genus, Dendroaspis, it is slender with dull green upper parts and cream underparts and generally ranges from 1.5 to 2.2 m (4 ft 11 in to 7 ft 3 in) in length. Described by Scottish naturalist Thomas Traill in 1843, it has two recognised subspecies: the nominate subspecies from central and west sub-Saharan Africa and the eastern black-tailed subspecies from eastern sub-Saharan Africa, mainly western Kenya.
Predominantly
Taxonomy and etymology
Jameson's mamba was first
In 1936, British biologist
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Description
Jameson's mamba is a long and slender snake with smooth scales and a tail which typically accounts for 20 to 25% of its total length. The total length (including tail) of an adult snake is approximately 1.5–2.2 m (4 ft 11 in – 7 ft 3 in). It may grow as large as 2.64 m (8 ft 8 in).[12] The general consensus is that the sexes are of similar sizes, although fieldwork in southeastern Nigeria found that males were significantly larger than females.[13] Adults tend to be dull green across the back, blending to pale green towards the underbelly with scales generally edged with black. The neck, throat and underparts are typically cream or yellowish in colour. Jameson's mamba has a narrow and elongated head containing small eyes and round pupils. Like the western green mamba, the neck may be flattened. The subspecies D. jamesoni kaimosae, which is found in the eastern part of the species' range, features a black tail, while central and western examples typically have a pale green or yellow tail.[12] The thin fangs are attached to the upper jaw and have a furrow running down their anterior surface.[4]
Scalation
The number and pattern of scales on a snake's body play a key role in the identification and differentiation at the species level.[14] Jameson's mamba has between 15 and 17 rows of dorsal scales at midbody, 210 to 236 (Subsp.) jamesoni) or 202 to 227 ventral scales (Subsp. kaimosae), 94 to 122 (Subsp. jamesoni) or 94 to 113 (Subsp. kaimosae) divided subcaudal scales, and a divided anal scale.[a] Its mouth is lined with 7 to 9 (usually 8) supralabial scales above and 8 to 10 (usually 9) sublabial scales below, the fourth ones located over and under the eye.[16] Its eyes have three preocular, three postocular and one subocular scale.[12]
Distribution and habitat
Jameson's mamba occurs mostly in
Found in
Behaviour and ecology
Jameson's mamba is a highly agile snake. Like other mambas it is capable of flattening its neck in mimicry of a cobra when it feels threatened, and its body shape and length give an ability to strike at significant range. Generally not aggressive, it will typically attempt to escape if confronted.[12][13]
Breeding
In Nigeria males fight each other for access to females (and then breed) over the dry season of December, January and February;[13] mating was recorded in September in the Kakamega Forest in Kenya.[17] Jameson's mamba is oviparous; the female lays a clutch of 5–16 eggs; in Nigeria laying was recorded from April to June, and most likely soon after November in Uganda.[17] Egg clutches have been recovered from abandoned termite colonies.[13]
Diet and predators
Jameson's mamba has been difficult to study in the field due to its arboreal nature and green coloration. It has not been observed hunting but is thought to use a sit-and-wait strategy, which has been reported for the eastern green mamba. The bulk of its diet is made up of birds and tree-dwelling mammals,[13] such as cisticolas, woodpeckers, doves, squirrels, shrews and mice.[17] Smaller individuals of under 100 cm (40 in) in length have been recorded feeding on lizards such as the common agama, and toads. There is no evidence they have adapted to hunting terrestrial rodents such as rats,[13] though they have been recorded eating rodents in Kenya, and have accepted them in captivity.[17]
The main predators of this species are
Venom
Jameson's mamba is classified as a Snake of Medical Importance in Sub-Saharan Africa by the World Health Organization,[b][19] although there are few records of snakebites.[17] Field observations over a 16-year period in the Niger Delta in southern Nigeria found that both humans and snakes were most active in rural areas during the rainy season, April to August, hence rendering this a peak period for snakebite. As well as succumbing to snakebites, workers were reported to have perished from falling from trees after encountering Jameson's mambas in the canopy of trees in palm oil plantations.[20] Snake bites are rare in cities but more common in forested areas in countries such as the Democratic Republic of the Congo; the country's poor infrastructure and lack of facilities render access to antivenom difficult.[21]
Like other mambas, the venom of the Jameson's mamba is highly
Similarly to the venom of most other mambas, Jameson's mamba's contains predominantly
Treatment
The speed of onset of envenomation means that urgent medical attention is needed.[17] Standard first aid treatment for any bite from a suspected venomous snake is the application of a pressure bandage, minimisation of the victim's movement, and rapid conveyance to a hospital or clinic. Due to the neurotoxic nature of green mamba venom, an arterial tourniquet may be beneficial.[26] Tetanus toxoid is sometimes administered, though the main treatment is the administration of the appropriate antivenom.[27] Trivalent and monovalent[d] antivenoms for the black, eastern green, and Jameson's mambas became available in the 1950s and 1960s.[29]
See also
Notes
- ^ A divided scale is one split down the midline into two scales.[15]
- ^ Snakes of medical Importance include those with highly dangerous venom resulting in high rates of morbidity and mortality, or those that are common agents in snakebite.[19]
- ^ The strength or toxicity of snake venom is traditionally measured using the LD50 (lethal dose 50%) test; in essence, injecting a certain amount of toxin into number of mice and recording what dose kills half of them.[23]
- ^ A monovalent antivenom is specific for one toxin or species, while a polyvalent one is effective against multiple toxins or species.[28]
References
- ^ Luiselli, L., Wagner, P., Branch, W.R. & Howell, K. 2021. "Dendroaspis jamesoni". The IUCN Red List of Threatened Species 2021: e.T13265784A13265793. https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T13265784A13265793.en Archived 2021-12-16 at the Wayback Machine. Downloaded on 18 September 2021.
- ^ "Dendroaspis jamesoni". Integrated Taxonomic Information System. Retrieved 8 March 2015.
- ^ a b c d Uetz, Peter. "Dendroaspis jamesoni (Traill, 1843)". The Reptile Database. Archived from the original on 4 November 2013. Retrieved 27 April 2012.
- ^ a b Traill, Thomas (1843). "Description of the Elaps Jamesoni [sic], a New Species from Demerara". Edinburgh New Philosophical Journal. 34: 53–55 – via Internet Archive.
- ISBN 978-1-4214-0135-5. (Dendroaspis jamesoni, p. 133).
- ^ "Dendroaspis". Integrated Taxonomic Information System. Retrieved 9 December 2013.
- ISBN 978-0-19-910207-5.
- ^ Duméril, Auguste Henri André (1856). "Note sure les Reptiles du Gabon". Revue et magasin de zoologie pure et appliquée (in French). 2 (8): 553–562 [557–558]. Archived from the original on 2021-08-03. Retrieved 2021-08-03.
- ^ Brongersma, Leo Daniel (1936). "Herpetological note XIII". Zoologische Mededelingen. 19: 135.
- ^ Loveridge, Arthur (1936). "New tree snakes of the genera Thrasops and Dendraspis from Kenya Colony". Proceedings of the Biological Society of Washington. 49: 63–66. Archived from the original on 2016-03-05. Retrieved 2018-02-20.
- ^ from the original on 2020-10-06. Retrieved 2020-01-29.
- ^ ISBN 978-0-7136-6817-9.
- ^ from the original on 2021-12-16. Retrieved 2021-07-31.
- ^ Hutchinson, Mark; Williams, Ian (2018). "Key to the Snakes of South Australia" (PDF). South Australian Museum. Government of South Australia. Archived from the original (PDF) on 18 July 2019. Retrieved 19 August 2021.
- ^ Macdonald, Stewart. "snake scale count search". Australian Reptile Online Database. Archived from the original on 2 March 2021. Retrieved 3 May 2019.
- ISBN 978-1-4214-2719-5.
- ^ ISBN 978-1-4729-6028-3.
- ^ Mattison, Chris (1987). Snakes of the World. Facts on File, Inc. p. 164.
- ^ a b WHO Expert Committee on Biological Standardization. "Guidelines for the production, control and regulation of snake antivenom immunoglobulins" (PDF). WHO Technical Report Series, No. 964. pp. 224–226. Archived (PDF) from the original on 14 February 2020. Retrieved 1 January 2019.
- (PDF) from the original on 2017-08-13. Retrieved 2021-03-10.
- ^ Cunningham, Hugh Kinsella (9 September 2019). "How Snakebites Became an Invisible Health Crisis in Congo". Pulitzer Center. Archived from the original on 31 July 2021. Retrieved 31 July 2021.
- ^ PMID 11990104.
- ^ "Snake Venom". School of Chemistry. University of Bristol. Archived from the original on 15 September 2009. Retrieved 18 September 2021.
- S2CID 42454467.
- PMID 11990107.
- from the original on 2021-08-25. Retrieved 2021-08-25.
- (PDF) from the original on 2020-11-25. Retrieved 2021-03-10.
- (PDF) from the original on 2021-09-18. Retrieved 2021-09-18.
- ISBN 978-1-920544-64-5. Archivedfrom the original on 2021-12-16. Retrieved 2021-07-31.
External links
- Media related to Dendroaspis jamesoni at Wikimedia Commons