Acanthophis

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Acanthophis
Acanthophis laevis.jpg
Acanthophis laevis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Elapidae
Genus: Acanthophis
Daudin, 1803 [1]
Species

See taxonomy

Acanthophis is a genus of elapid snakes. Commonly called death adders, they are native to Australia, New Guinea and nearby islands, and are among the most venomous snakes in the world. Despite their common name, they are not adders at all and belong to the Elapidae family (like cobras). The name of the genus derives from the Ancient Greek akanthos/ἄκανθος ('spine') and ophis/ὄφις ('snake'), referring to the spine on the death adder's tail.

Contents

Eight species are listed by ITIS, [2] though it remains unclear how many species this genus includes, with figures ranging from 4 to 15 species being quoted.

Taxonomy

French naturalist François Marie Daudin established the genus Acanthophis in 1803, with the common death adder (A. cerastinus) as its only species. [3]

Although the death adders resemble vipers of the family Viperidae, they are actually members of the family Elapidae, which includes cobras, mambas, and coral snakes.

It remains unclear how many species are included in this genus. Traditionally, only A. antarcticus, A. praelongus and A. pyrrhus have been recognised. In 1985, Wells & Wellington proposed four new species – A. armstrongi, A. hawkei, A. lancasteri, and A. schistos – but these were not widely adopted at the time. [4] In 1998 five new species were described (A. barnetti, A. crotalusei, A. cummingi, A. wellsi and A. woolfi) [5] and in 2002 an additional three were described (A. groenveldi, A. macgregori and A. yuwoni). [6] These were received with scepticism, [7] [8] [9] and only A. wellsi, where an extended description has been published, [7] has been widely recognised. [2] [10] Further confusion exists over the death adders from Papua New Guinea and Indonesia. They have variously been placed in A. antarcticus or A. praelongus. In 2005 it was shown that neither is appropriate, and the New Guinea death adders fall into two main clades: [11] The rather smooth-scaled A. laevis complex (including death adders from Seram), and the rough-scaled A. rugosus complex. The latter can be divided into two sub-clades; one, A. rugosus sensu stricto , from southern New Guinea, and a second, A. hawkei, from northern Queensland and the Northern Territory in Australia. It is likely some of these include more than one species, as populations included in e.g. A. laevis show extensive variation in both pattern and scalation. [11]

Species

ImageSpecies [2] [10] Authority [10] Subspecies*Common nameGeographic range
Z07 4504 export.jpg A. antarcticus T(Shaw, 1794)2 [12] Common death adder Australia [11]
A. cryptamydros Maddock, Ellis, Doughty, L.A. Smith & Wüster, 20150 [13] Kimberley death adderAustralia [13] [14]
A. hawkei Wells & Wellington, 19850 [15] Barkly Tableland death adderAustralia [15]
Acanthophis laevis.jpg A. laevis Macleay, 18780 [16] Smooth-scaled death adderIndonesia, Papua New Guinea [16]
Acanthophis praelongus 1.jpg A. praelongus Ramsay, 18770 [17] Northern death adderAustralia [11]
Acanthopis pyrrhus - Christopher Watson.jpg A. pyrrhus Boulenger, 18980 [18] Desert death adderAustralia [18]
A. rugosus Loveridge, 19480 [19] Rough-scaled death adderAustralia, Indonesia [19]
A. wellsi Hoser, 19981 [20] Pilbara death adderAustralia [20]

* Not including the nominate subspecies.
T Type species.

Description

Death Adder. Photo taken at Brisbane Forest Park, Brisbane, Queensland, Australia Death-Adder.jpg
Death Adder. Photo taken at Brisbane Forest Park, Brisbane, Queensland, Australia

Death adders are very viper-like in appearance, having a short, robust body, triangular shaped heads, small subocular scales, many small scales on the top of the head, and elevated supraocular scales. Dorsal scales may be smooth or keeled. Body patterning is generally crossbanding, and they have vertically elliptical pupils. [21] Their fangs are also longer and more mobile than for most other elapids, although still far from the size seen in some of the true vipers. Despite their name, they are not related to adders, which are members of the family Viperidae, and their similar appearance is due to convergent evolution.

They normally take 2–3 years to reach adult size. Females are generally slightly larger than the males. They can also be easily distinguished from other Australian snakes because of a small, worm like lure on the end of their tail, which is used to attract prey. Most have large bands around their bodies, though the colour itself is variable, depending on their locality. Colours are usually black, grey or red and yellow, but also include brown and greenish-grey.

Death adders are ovoviviparous with the embryos developing in membranous sacs inside the female who will give birth to litters of 8 to 30 live neonates. [21]

Origin of name

The name was originally "deaf adder". Psalm 58 says: They are as venomous as the poison of a serpent; even like the deaf adder that stoppeth her ears; Which refuseth to hear the voice of the charmer: charm he never so wisely. Early settlers of Australia also called them "deaf adders". [22] How "deaf" became "death" is not recorded.

Unlike other snakes that tend to flee from human disturbance, the death adder is inclined to hold its ground, leading to the notion that the death adder cannot hear. However, death adders, like other snakes, perceive ground vibrations.

Hunting

Unlike most snakes, death adders do not actively hunt, but rather lie in ambush and draw their prey to them. [23] When hungry, death adders bury themselves among the substrate. This may be leaf litter, soil or sand, depending on their environment. The only part of themselves they expose are their head and their tail, both generally very well camouflaged. The end of the tail is used for caudal luring and when wiggled, it is easily mistaken for a grub or worm. When the snake's prey attempts to seize it, the death adder strikes. Although it has been claimed to have the quickest strike of any snake in the world, [24] this topic has not been well enough studied to make reliable comparisons. [25] They commonly feed on local geckos such as the Dubious dtella.

Venom

Death adders can inject on average 40–100 mg of highly toxic venom with a bite. The LD50 of the venom was reported as 0.4–0.5 mg/kg subcutaneous and it is completely neurotoxic, containing neither haemotoxins nor myotoxins, unlike the venoms of most venomous snakes.

A bite from a death adder can cause paralysis which seems minor at first but can cause death from a complete respiratory shutdown in six hours. Symptoms of envenomation can be reversed through the use of death adder antivenom, or using anticholinesterases, which break the synaptic blockade by making acetylcholine more available to the parasympathetic nervous system, thus mitigating the effects of the venom.

Before antivenom was introduced, it is reported that about 50% of death adder bites were fatal. A fatal bite is less likely now as the anti-venom is widely available and the progression of envenomation symptoms is slow.

Related Research Articles

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Elapidae is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydocephalus. Many members of this family exhibit a threat display of rearing upwards while spreading out a neck flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the 18 cm (7.1 in) white-lipped snake to the 5.85 m king cobra. Most species have neurotoxic venom that is channeled by their hollow fangs, and some may contain other toxic components in various proportions. The family includes 55 genera with around 360 species and over 170 subspecies.

<i>Bungarus</i> Genus of venomous snakes

Bungarus is a genus of elapids native to Asia. Often found on the floor of tropical forests in South Asia, Southeast Asia and Southern China, they are medium-sized, highly venomous snakes with a length typically not exceeding 2 metres. These are nocturnal ophiophagious predators which prey primarily on other snakes at night, occasionally taking lizards, amphibians and rodents. Most species are with banded patterns acting as a warning sign to their predators. Despite being considered as generally docile and timid, kraits are capable of delivering highly potent neurotoxic venom which is medically significant with potential lethality to humans. The genus currently holds 16 species and 5 subspecies.

<i>Agkistrodon</i> Genus of snakes

Agkistrodon is a genus of venomous pit vipers commonly known as American moccasins. The genus is endemic to North America, ranging from the Southern United States to northern Costa Rica. Eight species are currently recognized, all of them monotypic and closely related. Common names include: cottonmouths, copperheads, and cantils.

<span class="mw-page-title-main">Eastern brown snake</span> Highly venomous snake native to Australia

The eastern brown snake, often referred to as the common brown snake, is a species of extremely venomous snake in the family Elapidae. The species is native to eastern and central Australia and southern New Guinea. It was first described by André Marie Constant Duméril, Gabriel Bibron, and Auguste Duméril in 1854. The adult eastern brown snake has a slender build and can grow to 2 m (7 ft) in length. The colour of its surface ranges from pale brown to black, while its underside is pale cream-yellow, often with orange or grey splotches. The eastern brown snake is found in most habitats except dense forests, often in farmland and on the outskirts of urban areas, as such places are populated by its main prey, the house mouse. The species is oviparous. The International Union for Conservation of Nature classifies the snake as a least-concern species, though its status in New Guinea is unclear.

<i>Naja</i> Genus of snakes

Naja is a genus of venomous elapid snakes commonly known as cobras. Members of the genus Naja are the most widespread and the most widely recognized as "true" cobras. Various species occur in regions throughout Africa, Southwest Asia, South Asia, and Southeast Asia. Several other elapid species are also called "cobras", such as the king cobra and the rinkhals, but neither is a true cobra, in that they do not belong to the genus Naja, but instead each belong to monotypic genera Hemachatus and Ophiophagus.

<i>Pseudechis</i> Genus of snakes

Pseudechis is a genus of venomous snakes in the family Elapidae. It contains the group of elapid species commonly referred to as the black snakes. Species of Pseudechis are found in every Australian state with the exception of Tasmania, and some species are found in Papua New Guinea. They inhabit a variety of habitat types, from arid areas to swampland. All species are dangerous and can inflict a potentially lethal bite. Most snakes in this genus reach about 2 m (6.6 ft) in total length, and vary in colour. Some species are brown, whereas others are black. The most recognisable and widespread species in the genus are the red-bellied black snake and the mulga snake. These snakes feed on lizards, frogs, birds, small mammals, and even other snakes. All species of Pseudechis lay eggs with the exception of the red-bellied black snake P. porphyriacus which is viviparous. The genus Pailsus is a synonym of Pseudechis, and more work is needed to understand species limits among the smaller species of the group.

<span class="mw-page-title-main">Common death adder</span> Species of snake

The common death adder is a species of death adder native to Australia. It is one of the most venomous land snakes in Australia and globally. While it remains widespread, it is facing increased threat from the ongoing Australian cane toad invasion.

<span class="mw-page-title-main">Desert death adder</span> Species of snake

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<span class="mw-page-title-main">Spider-tailed horned viper</span> Species of snake

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<span class="mw-page-title-main">Coastal taipan</span> Venomous snake species native to Australia

The coastal taipan, or common taipan, is a species of extremely venomous snake in the family Elapidae. Described by Wilhelm Peters in 1867, the species is native to the coastal regions of northern and eastern Australia and the island of New Guinea. The second-longest venomous snake in Australia, the coastal taipan averages around 2.0 m (6.6 ft) long, with the longest specimens reaching 2.9 m (9.5 ft) in length. It has light olive or reddish-brown upperparts, with paler underparts. The snake is considered to be a least-concern species according to the International Union for Conservation of Nature.

<span class="mw-page-title-main">Northern death adder</span> Species of snake

The northern death adder is a species of venomous snake in the family Elapidae.

<span class="mw-page-title-main">Smooth-scaled death adder</span> Species of snake

The smooth-scaled death adder is a species of venomous snake in the family Elapidae. The species is endemic to Southeast Asia and Oceania.

The rough-scaled death adder is a species of venomous snake in the family Elapidae.

The Barkly Tableland death adder is a species of venomous snake in the family Elapidae. The exact distribution of the species is unclear, but suitable habitat for the plains death adder consists of flat, treeless, cracking-soil riverine floodplains. Based on the presence of suitable habitat, the potential geographic range for this species extends from Western Queensland, across the north of the Northern Territory to north-east Western Australia. Disjunct populations of the plains death adder are known to occur in the Mitchell Grass Downs of western Queensland, the Barkly Tableland on the Northern Territory/Queensland border and east of Darwin in the Northern Territory. The snake is named after former Prime Minister of Australia Bob Hawke.

The Kimberley death adder is a species of venomous snake in the family Elapidae native to northwestern Australia.

The Pilbara death adder, also known commonly as Wells' death adder, is a species of venomous snake in the family Elapidae. The species is one of the eight members of the genus Acanthophis, a genus which is found throughout northwestern and southwestern Australia and some parts of southern Papua New Guinea. The species Acanthophis wellsi is endemic to Western Australia.

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References

  1. ↑ "Acanthophis". Dahms Tierleben. [www.dahmstierleben.de/systematik/Reptilien/Squamata/Serpentes/colubroidea/Elapidae].
  2. 1 2 3 "Acanthophis ". Integrated Taxonomic Information System . Retrieved 10 March 2011.
  3. ↑ Daudin, François Marie (1802). Histoire naturelle, générale et particulière, des reptiles : ouvrage faisant suite à l'Histoire naturelle générale et particulière, composée par Leclerc de Buffon, et rédigée par C.S. Sonnini. Vol. 97. Paris: F. Dufart. pp. 289–296.
  4. ↑ Ellis, Ryan J.; Kaiser, Hinrich; Maddock, Simon T.; Doughty, Paul; Wüster, Wolfgang (29 June 2021). "An evaluation of the nomina for death adders (Acanthophis Daudin, 1803) proposed by Wells & Wellington (1985), and confirmation of A. cryptamydros Maddock et al., 2015 as the valid name for the Kimberley death adder". Zootaxa. 4995 (1): 161–172. doi: 10.11646/zootaxa.4995.1.9 . ISSN   1175-5334. PMID   34186811.
  5. ↑ Hoser, R. (1998): Death adders (genus Acanthophis): an overview, including descriptions of five new species and one subspecies. Monitor 9(2): 20-30, 33-41. available online
  6. ↑ Hoser, R. (2002): Death Adders (Genus Acanthophis): An Updated overview, including descriptions of 3 New Island species and 2 New Australian subspecies. Crocodilian - Journal of the Victorian Association of Amateur Herpetologists, September 2002: 5-11, 16-22, 24-30, front and back covers. available online
  7. 1 2 Aplin, K.P. & S.C. Donnellan (1999): An extended description of the Pilbara Death Adder, Acanthophis wellsi Hoser (Serpentes: Elapidae), with notes on the Desert Death Adder, A. pyrrhus Boulenger, and identification of a possible hybrid zone. Records of the Western Australian Museum 19: 277-298.
  8. ↑ Wüster, W., B. Bush, J.S. Keogh, M. O'Shea & R. Shine (2001): Taxonomic contributions in the "amateur" literature: comments on recent descriptions of new genera and species by Raymond Hoser. Litteratura Serpentium 21: 67-79, 86-91. available online (PDF) Archived 9 August 2007 at the Wayback Machine
  9. ↑ Williams, D., W. Wüster & B. Fry (2006): The good, the bad and the ugly: Australian snake taxonomists and a history of the taxonomy of Australia's venomous snakes. Toxicon 48: 919-930. available online (PDF) Archived 25 December 2006 at the Wayback Machine
  10. 1 2 3 Reptile Database (version 10 March 2011). Acanthophis.
  11. 1 2 3 4 Wüster, Wolfgang; Dumbrell; Hay, C.; Pook, C.E.; Williams, D.J.; Fry, B.G. (2005). "Snakes across the Strait: Trans-Torresian phylogeographic relationships in three genera of Australasian snakes (Serpentes: Elapidae: Acanthophis, Oxyuranus and Pseudechis)" (PDF). Molecular Phylogenetics and Evolution. 34 (1): 1–14. doi:10.1016/j.ympev.2004.08.018. PMID   15579378.
  12. ↑ Reptile Database (version 10 March 2011). Acanthophis antarcticus.
  13. 1 2 Maddock, S. T., R. J. Ellis, P. Dougthy, L. A. Smith & W. Wüster (2015): A new species of death adder (Acanthophis: Serpentes: Elapidae) from north-western Australia. Zootaxa 4007: 301–326. available online (PDF)
  14. ↑ (14 Sep 2015). New Species of Venomous Snake Discovered in Australia.
  15. 1 2 Reptile Database (version 10 March 2011). Acanthophis hawkei.
  16. 1 2 Reptile Database (version 10 March 2011). Acanthophis laevis.
  17. ↑ Reptile Database (version 10 March 2011). Acanthophis praelongus.
  18. 1 2 Reptile Database (version 10 March 2011). Acanthophis pyrrhus.
  19. 1 2 Reptile Database (version 10 March 2011). Acanthophis rugosus.
  20. 1 2 Reptile Database (version 10 March 2011). Acanthophis wellsi.
  21. 1 2 "Death Adders". University of Melbourne. 2 May 2017. Archived from the original on 31 March 2021. Retrieved 10 October 2021.
  22. ↑ "CSL Antivenom Handbook: CSL Death Adder Antivenom". Archived from the original on 12 October 2008. Retrieved 26 May 2013.
  23. ↑ Mahony, Stephen (2020). "Common Death Adder". The Australian Museum. Retrieved 9 October 2021.
  24. ↑ Baker, Kevin (4 July 2016). The World's Most Dangerous Animals SUBTITLE. eBookIt.com. ISBN   9781456626976.
  25. ↑ Penning, David A.; Sawvel, Baxter; Moon, Brad R. (March 2016). "Debunking the viper's strike: harmless snakes kill a common assumption". Biology Letters. 12 (3): 20160011. doi:10.1098/rsbl.2016.0011. ISSN   1744-9561. PMC   4843225 . PMID   26979562.

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