User:HDXFLDD/沙盒

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东部绿曼巴蛇
A bright lime-green snake on a dark background
科学分类 编辑
界： 动物界 Animalia
门： 脊索动物门 Chordata
纲： 爬行綱 Reptilia
目： 有鳞目 Squamata
亚目： 蛇亚目 Serpentes
科： 眼镜蛇科 Elapidae
属： 曼巴蛇屬 Dendroaspis
种：
东部绿曼巴蛇 D. angusticeps
二名法
Dendroaspis angusticeps
(A. Smith, 1849)[1]
东部绿曼巴蛇地理分布范围
異名[2]
List
  • Naja angusticeps
    — Smith, 1849
  • Naja angusticeps
    — Duméril & Bibron, 1854
  • Dendraphis angusticeps
    — Günther, 1858
  • Dendrospis [sic] angusticeps
    — Boulenger, 1897
  • Dendroaspis sjöstedti
    — Lönnberg, 1910
  • Dendraspis [sic] angusticeps
    — Sternfeld, 1910
  • Dendroaspis angusticeps
    — Razetti & Msuya, 2002


东部绿曼巴蛇 (Dendroaspis angusticeps) 是曼巴属Dendroaspis的一种剧毒蛇种，生活在东非南部沿海地区。1849年，苏格兰外科医生兼动物学家安德鲁·史密斯描述道，它体型纤细，背部为鲜绿色，腹部为黄绿色。成年雌性平均体长约2米(6英尺7英寸)，雄性略小一些。

东部绿曼巴蛇性情害羞，善于隐藏，人们也很难见到。之所以说它们善于隐藏，主要是因为生活在常绿灌木丛和树林中，它们身体呈现的绿色可以很好地和周围环境融合。人们还观察到东部绿曼巴会像许多蝰蛇一样，“守株待兔”伏击捕食，和其他眼镜蛇典型的主动觅食方式不同。它捕食鸟类，卵，蝙蝠和啮齿类动物，如小老鼠，大鼠和沙鼠。

它的毒液由神经毒素和心脏毒素组成。中毒的症状包括咬伤部位肿胀，头晕和恶心，伴有呼吸和吞咽困难，心律不齐和抽搐，并发展为呼吸衰竭。造成严重中毒的咬伤可能很快即可致命。

分类[编辑]

1849年，苏格兰外科医生和动物学家安德鲁·史密斯（ Andrew Smith）首次将东部绿曼巴蛇描述为眼镜蛇（Naja angusticeps），他将这一命名汇报至纳塔尔（Natal）及东至马普托湾的地区。[3]物种名称angusticeps源自拉丁语单词angustus ，意为“ 窄的”，[4]和ceps，当用在复合词中时是caput的缩写形式，意为“头“。[5]1865年，英籍德裔动物学家阿尔伯特·冈瑟（Albert Günther）给来自莫桑比克北部赞比西河的曼巴蛇命名为中介曼巴（Dendroaspis intermedius）[6]此后这也是东部绿曼巴蛇（D. angusticeps） 的异名。[7]

In 1896, the Belgian-British zoologist George Albert Boulenger combined the species Dendroaspis angusticeps with the black mamba (Dendroaspis polylepis),[8] a lumping diagnosis that remained in force until 1946, when the South African herpetologist Vivian FitzSimons published a paper after examining approximately 50 eastern green mamba and 85 black mamba specimens. He concluded that the differences in build, scalation, colouration and behaviour warranted splitting them into separate species.[9][10] The British biologist Arthur Loveridge augmented FitzSimons' work with material from outside South Africa, noting some overlap in scalation but supporting the separation.[11] A 2016 genetic analysis showed the eastern green and black mambas are each others' closest relatives,[12] their common ancestor diverging from a lineage that gave rise to Jameson's mamba (Dendroaspis jamesoni) and the western green mamba (Dendroaspis viridis).[13]

As well as being called the eastern green mamba, the species is also frequently known as the common green mamba, East African green mamba, white-mouthed mamba, or simply the green mamba.[14]

Description[编辑]

A bright green snake in a tree branch in a terrarium-like enclosure
An eastern green mamba

The eastern green mamba is a large snake, with a slightly compressed and very slender body with a medium to long tapering tail. Adult males average around 1.8米（5英尺11英寸） in total length, while females average 2.0米（6英尺7英寸）. This species rarely exceeds lengths of 2.5米（8英尺2英寸）. In general, the total length is 4–4.3 times the length of the tail.[15][16][17] The adult eastern green mamba has bright green upperparts—occasionally with isolated yellow scales—and a pale yellow-green belly. Sometimes they are duller-coloured before moulting. Juveniles are blue-green, becoming bright green when they are around 75厘米（2英尺6英寸） long.[16] The coffin-shaped head is long and slender,[17] with a prominent canthus which is slightly demarcated from the neck. When threatened or otherwise aroused, the eastern green mamba is capable of flattening its neck area, though no real hood is formed.[14] The medium-sized eyes have round pupils,[17] the borders of which have a narrow golden or ochre edge; the irises are olive green, becoming bright green posteriorly. The inside of the mouth may be white or bluish-white.[15]

Other green snakes are often called "green mambas" in southern Africa, including green forms of the boomslang (Dispholidus typus), which can be distinguished by their larger eyes and shorter heads. They are also venomous. Green bushsnakes of the genus Philothamnus[16] are also commonly confused with smaller Eastern green mambas.

Scalation[编辑]

参见：Snake scale § Nomenclature of scales

The number and pattern of scales on a snake's body are a key element of identification to species level.[18] The eastern green mamba has between 17 and 21 rows of dorsal scales at midbody, 201 to 232 ventral scales, 99 to 126 divided subcaudal scales, and a divided anal scale.[a] Its mouth is lined with 7–9 supralabial scales above, the fourth one located under the eye, and 9–11 sublabial scales below. Its eyes have three preocular and 3–5 postocular scales.[16]

Distribution and habitat[编辑]

The eastern green mamba is native to regions near the coastlines of southern Africa and East Africa. Its range extends from Kenya south through Tanzania, Malawi, and eastern Zimbabwe; it can also be found in Zanzibar and northern Mozambique.[14][15] An isolated and genetically distinct population is found in South Africa from the extreme northeastern part of Eastern Cape along the KwaZulu-Natal coastline and into southern Mozambique.[7]

An elusive species, it is primarily arboreal (living in trees) and usually well camouflaged in foliage. Some herpetologists believe its habitat is limited to tropical rainforests in coastal lowlands.[20] Others experts believe it can also be found in coastal bush, and dune and montane forest.[21] Unlike its close relative the black mamba, the eastern green mamba is rarely found in open terrain and prefers relatively dense, well-shaded vegetation. As well as wild forest habitats, it is also commonly found in thickets and farm trees such as citrus, mango, coconut, and cashew. In coastal East Africa, it is known to enter houses and may even shelter in thatched-roof dwellings. Specimens have been found at elevations up to 1,500米（4,900英尺） above sea level.[17]

Conservation status[编辑]

The species' conservation status has not been assessed by the International Union for Conservation of Nature (IUCN). It is fairly common throughout its range, and populations are believed to be stable. Large concentrations of two to three individuals per hectare have been documented in coastal Kenya and southern Tanzania, and in one instance a group of five were seen in a single tree. Although populations are stable overall, habitat destruction and deforestation may pose a threat.[17] In South Africa, it is rated as "vulnerable" as its habitat had become highly fragmented by coastal housing development.[7]

Behaviour and ecology[编辑]

A bright green snake on a log next to shedded skin
A green mamba at a German serpentarium next to shed skin

A diurnal species, the eastern green mamba is active by day and sleeps at night coiled up in foliage or rarely a hollow within the trunk or branch.[16][14] An agile snake and an adept climber, it is not commonly found on the ground though may come down to bask in the morning sun (thermoregulation).[17] In a 27-day study of the movement patterns of two adults found their activity area to be relatively small, comparable to other predators who ambush prey rather than hunt (in contrast to most elapid species, including other mambas, who tend to hunt and forage). The study's preliminary evidence shed light on the species' feeding methods, suggesting it may be primarily an ambush predator due to its sit-and-wait behaviour. This evidence does not preclude active foraging, however; a specimen was also observed systematically hunting a sleeping bat.[22]

There is no evidence that the eastern green mamba migrates. Thought to be relatively sedentary, it can remain in the same location for days, apparently moving most commonly to find food or mates. On average, individuals move only about 5.4米（18英尺） per day.[20][22] They generally avoid contact with people and other predators, attacking them only if they feel threatened.[14]

Reproduction and lifespan[编辑]

The eastern green mamba is solitary except during breeding season. Gravid females tend to be sedentary, but males actively seek and court prospective mates during the rainy season between April and June. Males have been seen engaging in agonistic behaviour; they may fight each other over mating opportunities, or possibly to establish a dominance hierarchy. Typically, one male initiates a fight by moving on top of the other's body and tongue-flicking, after which the two entwine and push, attempt to pin the other's head to the ground. Male combat can last for several hours, but is less aggressive than that commonly seen in the black mamba; combatants do not bite each other.[20]

Males locate females by following a scent trail. The male courts the female by aligning his body along the female's while rapidly tongue-flicking. If the female is receptive to mating, she lifts her tail; cloacal juxtaposition follows. Courtship and mating take place in trees, after which the female can lay 4–17 eggs (10–15 on average), occurring in October and November.[20] The eggs are small and elongated, usually 47–58 x 25–28 mm,[15][16] and usually laid in leaf litter in hollow trees.[16] The incubation period is around three months.[17] When the young emerge, they are approximately 30至45 cm（12至18英寸）[16] in the wild, and 44 cm（17英寸） in captivity.[20] They usually reach adult colouration at 75 cm（30英寸）.[15][16] Hatchlings tend to grow to 50至80 cm（20至31英寸） in their first year. As they age, their growth rates decrease but never completely stop.[20]

The oldest recorded eastern green mamba was a captive specimen that lived 18.8 years.[23] Another captive specimen lived 14 years.[21]

Diet[编辑]

The eastern green mamba preys primarily on birds and their eggs, and small mammals including bats. It is also believed to eat arboreal lizards.[15][16] It uses a sit-and-wait strategy, though one specimen was recorded actively hunting sleeping bats.[22] The species is also known to raid the nests of young birds.[24] Sit-and-wait tactics may be successful with highly mobile prey, such as adult birds or rodents. Documented prey include the sombre greenbul, which occur in dense areas of natural and cultivated vegetation along Kenya's coastline. Ionides and Pitman (1965) reported a large bushveld gerbil in the stomach of a green mamba in Tanzania. Although the bushveld gerbil does not occur in Kenya, green mambas prey on the seven species of gerbil that inhabit parts of its range.[22]

Predators[编辑]

The eastern green mamba has few natural predators. Humans, mongooses, snake eagles and genets commonly prey on it, and hornbills and other snakes prey on juveniles.[22]

Venom[编辑]

A bright green snake on a log
The eastern green mamba has a rapid-acting venom.

The eastern green mamba has the least toxic venom of the three green mamba species, but it is still highly venomous.[25] Although the most commonly encountered green mamba, it generally avoids people. The peak period for bites is the species' breeding season from September to February, during which they are most irritable.[26] A survey in southern Africa from 1957–1979 recorded 2,553 venomous snakebites, 17 of which were confirmed as eastern green mambas. Of these 17, 10 had symptoms of systemic envenomation, though no victims died.[27] The snake tends to bite repeatedly,[26] and one bite can contain 60–95 mg of venom by dry weight.[28] The median lethal dose (LD50) in mice is 1.3 mg/kg[17] through the subcutaneous route, and 0.45 mg/kg through the IV route.[29]

Symptoms of envenomation by this species include pain and swelling of the bite site, which can progress to local necrosis or gangrene.[30] Systemic effects include dizziness and nausea, difficulty breathing and swallowing, irregular heartbeat, and convulsions.[17] Neurotoxic symptoms such as paralysis may be mild or absent.[30] Bites that produce severe envenomation can be rapidly fatal; fatal outcomes as quickly as 30 minutes have been recorded (although the period is likely slower for Dendroaspis angusticeps).[17]

In 2015, the proteome (complete protein profile) of eastern green mamba venom was assessed and published, revealing 42 distinct proteins and the nucleoside adenosine. The predominant agents are those of the three-finger toxin family, including aminergic toxins, which act on muscarinic and adrenergic receptors, and fasciculins,[31] which are anticholinesterase inhibitors that cause muscle fasciculation.[26] Another prominent component is a group of proteins known as dendrotoxins; although structurally homologous to Kunitz-type protease inhibitors, they block voltage-dependent potassium channels, stimulating the release of acetylcholine and causing an excitatory effect.[31] Another Kunitz-type protein present is calcicludine, which blocks high-voltage-activated calcium channels.[32] Individually, most of these components do not exhibit potent toxicity in vitro,[31] but are thought to have a synergistic effect in nature.[31]

Similarly to the venom of most other mambas, the eastern green mamba's contains predominantly three-finger toxin agents. The exception is the black mamba, whose venom lacks the potent alpha-neurotoxin as well. It is thought this may reflect the species' preferred prey—small mammals for the mainly land-dwelling black mamba, versus birds for the other predominantly arboreal mambas. Unlike that of many snake species, the venom of mambas has little phospholipase A2.[13]

Treatment[编辑]

Standard first aid treatment for any bite from a suspectedly 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.[33] Tetanus toxoid is sometimes administered, though the main treatment is the administration of the appropriate antivenom.[34] A polyvalent antivenom produced by the South African Institute for Medical Research is used to treat eastern green mamba bites.[30]

Notes[编辑]

  1. ^ A divided scale is one split down the midline into two scales.[19]

References[编辑]

  1. ^ Dendroaspis angusticeps. ITIS. [30 October 2012]. 
  2. ^ Uetz, Peter; Hallermann, Jakob. Dendroaspis angusticeps (SMITH, 1849). The Reptile Database. Reptarium association. [17 February 2012]. 
  3. ^ Smith, Andrew. Illustrations of the Zoology of South Africa, Reptilia. 4. London: Smith, Elder and Co. 1849. Plate 70. 
  4. ^ de Vaan, Michiel. Etymological Dictionary of Latin and the other Italic Languages. Boston: Leiden. 2018: 42 [2008]. ISBN 978-90-04-16797-1. 
  5. ^ Hall, Whitmore. The principal roots and derivatives of the Latin language, with a display of their incorporation into English. London: Longman, Green, Longman & Roberts. 1861: 153. 
  6. ^ Günther, Albert. Fourth account of new species of snakes in the collection of the British Museum. Annals and Magazine of Natural History. 3rd series. 1865, 15 (86): 89–98 [98]. doi:10.1080/00222936508681770. 
  7. ^ 7.0 7.1 7.2 Bates, Michael F.; Branch, William R.; Bauer, Aaron M.; Burger, Marius; Marais, Johan; Alexander, Graham; de Villiers, Marienne S. Atlas and Red List of the Reptiles of South Africa, Lesotho and Swaziland. Pretoria: South African National Biodiversity Institute, Pretoria. 2014: 397. ISBN 978-1-919976-96-9. 
  8. ^ Boulenger, George Albert. Catalogue of the snakes in the British Museum (Natural History). Printed by order of the Trustees British Museum (Natural History). Department of Zoology. 1896: 437. 
  9. ^ FitzSimons, V. Notes on some south African snakes, including a description of a new subspecies of Xenocalamus. Annals of the Transvaal Museum. 1946, 20: 379–393 [392–393]. 
  10. ^ Haagner, G. V.; Morgan, D. R. The maintenance and propagation of the Black mamba Dendroaspis polylepis at the Manyeleti Reptile Centre, Eastern Transvaal. International Zoo Yearbook. 1993, 32 (1): 191–196. doi:10.1111/j.1748-1090.1993.tb03534.x. 
  11. ^ Loveridge, Arthur. The green and black mambas of East Africa. Journal of the East Africa Natural History Society. 1950, 19 (5): 251–252. 
  12. ^ Figueroa, A.; McKelvy, A. D.; Grismer, L. L.; Bell, C. D.; Lailvaux, S. P. A species-level phylogeny of extant snakes with description of a new colubrid subfamily and genus. PLOS ONE. 2016, 11 (9): e0161070. Bibcode:2016PLoSO..1161070F. PMC 5014348 可免费查阅. PMID 27603205. doi:10.1371/journal.pone.0161070 可免费查阅. 
  13. ^ 13.0 13.1 Ainsworth, Stuart; Petras, Daniel; Engmark, Mikael; Süssmuth, Roderich D.; Whiteley, Gareth; Albulescu, Laura-Oana; Kazandjian, Taline D.; Wagstaff, Simon C.; Rowley, Paul; Wüster, Wolfgang; Dorrestein, Pieter C.; Arias, Ana Silvia; Gutiérrez, José M.; Harrison, Robert A.; Casewell, Nicholas R.; Calvete, Juan J. The medical threat of mamba envenoming in sub-Saharan Africa revealed by genus-wide analysis of venom composition, toxicity and antivenomics profiling of available antivenoms. Journal of Proteomics. 2018, 172: 173–189 [178]. PMID 28843532. doi:10.1016/j.jprot.2017.08.016. 
  14. ^ 14.0 14.1 14.2 14.3 14.4 Dendroaspis angusticeps. WCH Clinical Toxinology Resource. University of Adelaide. [26 April 2014]. 
  15. ^ 15.0 15.1 15.2 15.3 15.4 15.5 FitzSimons, Vivian F. M. A Field Guide to the Snakes of Southern Africa. HarperCollins. 1970: 169–170. ISBN 978-0-00-212146-0. 
  16. ^ 16.00 16.01 16.02 16.03 16.04 16.05 16.06 16.07 16.08 16.09 Marais, Jean. A Complete Guide to Snakes of Southern Africa. Cape Town: Random House Struik Publishers. 2004: 98–99. ISBN 978-1-8-6872-932-6. 
  17. ^ 17.00 17.01 17.02 17.03 17.04 17.05 17.06 17.07 17.08 17.09 Spawls, S.; Branch, B. The Dangerous Snakes of Africa. London: Blandford Press. 1995: 46–47. ISBN 978-0-88359-029-4. 
  18. ^ Hutchinson, Mark; Williams, Ian. Key to the Snakes of South Australia (PDF). South Australian Museum. Government of South Australia. 2018 [8 February 2019]. 
  19. ^ Macdonald, Stewart. snake scale count search. Australian Reptile Online Database. [3 May 2019]. 
  20. ^ 20.0 20.1 20.2 20.3 20.4 20.5 Haagner, G. V.; Morgan, D. R. The captive propagation of the Eastern green mamba Dendroaspis angusticeps. International Zoo Yearbook. January 1989, 28 (1): 195–199. doi:10.1111/j.1748-1090.1989.tb03280.x. 
  21. ^ 21.0 21.1 Branch, B. Branch's Field Guide Snakes Reptiles Southern Africa. Cape Town: Struik Publishers. 1994: 95 [1988]. ISBN 978-1-86825-575-7. 
  22. ^ 22.0 22.1 22.2 22.3 22.4 Angilletta, Michael J. Sedentary behaviors by Green Mambas Dendroaspis angusticeps (PDF). Herpetological Natural History. 1994, 2 (2): 105–111 [26 April 2014]. （原始内容 (PDF)存档于3 March 2016）. 
  23. ^ AnAge entry for Dendroaspis angusticeps. AnAge:The Animal Ageing and Longevity Database. Human Ageing Genomic Resources. [26 April 2014]. 
  24. ^ Phelps, T. Poisonous Snakes. London: Blandford. 1989: 272. ISBN 978-0-71-372114-0. 
  25. ^ O'Shea, Mark. Venomous Snakes of the World需要免费注册. New Jersey, US: Princeton University Press. 2005: 78. ISBN 978-0-691-12436-0. 
  26. ^ 26.0 26.1 26.2 Hodgson, Peter S.; Davidson, Terence M. Biology and treatment of the mamba snakebite. Wilderness and Environmental Medicine. 1996, 7 (2): 133–145 [134–136]. PMID 11990107. doi:10.1580/1080-6032(1996)007[0133:BATOTM]2.3.CO;2 可免费查阅. 
  27. ^ Christensen, P. A. Snakebite and the use of antivenom in southern Africa (PDF). South African Medical Journal. 1981, 59 (26): 934–938. PMID 7244896. 
  28. ^ Minton, Sherman. Venom diseases. Waukesha, Wisconsin: Thomas Press. 1974: 116. ISBN 978-0-398-03051-3. 
  29. ^ Department of the Navy Bureau of Medicine and Surgery. Venomous Snakes of the World: A Manual for Use by U.S. Amphibious Forces. New York: Skyhorse Publishing. 2013: 93. ISBN 978-1-62087-623-7. 
  30. ^ 30.0 30.1 30.2 Müller, G. J.; Modler, H.; Wium, C. A.; Veale, D. J. H.; Marks, C. J. Snake bite in southern Africa: diagnosis and management. Continuing Medical Education. 2012, 30 (10): 362–381 [362, 380–381]. 
  31. ^ 31.0 31.1 31.2 31.3 Lauridsen, Line P.; Laustsen, Andreas H.; Lomonte, Bruno; Gutiérrez, José María. Toxicovenomics and antivenom profiling of the Eastern green mamba snake ( Dendroaspis angusticeps ) (PDF). Journal of Proteomics. 2016, 136: 248–261 [249, 258–260]. PMID 26877184. doi:10.1016/j.jprot.2016.02.003. 
  32. ^ Schweitz, H.; Heurteaux, C.; Bois, P.; Moinier, D.; Romey, G.; Lazdunski, M. Calcicludine, a venom peptide of the Kunitz-type protease inhibitor family, is a potent blocker of high-threshold Ca2+ channels with a high affinity for L-type channels in cerebellar granule neurons. Proceedings of the National Academy of Sciences. 1994, 91 (3): 878–882. Bibcode:1994PNAS...91..878S. PMC 521415 可免费查阅. PMID 8302860. doi:10.1073/pnas.91.3.878. 
  33. ^ Dreyer, S. B.; Dreyer, J. S. Snake Bite: A review of Current Literature. East and Central African Journal of Surgery. November 2013, 18 (3): 45–52. ISSN 2073-9990. 
  34. ^ Gutiérrez, José María; Calvete, Juan J.; Habib, Abdulrazaq G.; Harrison, Robert A.; Williams, David J.; Warrell, David A. Snakebite envenoming (PDF). Nature Reviews Disease Primers. 2017, 3 (3): 17063. PMID 28905944. S2CID 4916503. doi:10.1038/nrdp.2017.63. 

External links[编辑]

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