Acanthophis
From Wikipedia, the free encyclopedia
| iAcanthophis | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Image:Acanthophis antarcticus.jpg | ||||||||||||||||
| Scientific classification | ||||||||||||||||
| ||||||||||||||||
| | ||||||||||||||||
Acanthophis is a genus of highly venomous elapid snakes. Commonly called death adders, they are native to Australia and nearby islands, and are among the most venomous snakes in the world. This genus currently consists of 15 known species.
Contents |
[edit] Description
Death adders are very viper-like in appearance, having triangular shaped heads and small subocular scales. They also have vertical pupils and many small scales on the top of the head. Like vipers, they have short, fat bodies (normally 50 – 90 cm (20 – 36 inches) long). 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 and appearance, they are not vipers at all, but elapids (like all Australian venomous snakes). This is a case of convergent evolution.
It normally takes 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 short spine protruding from their tails. Most have large bands around their bodies, though the color itself is variable. Colors are usually grey or red, but also include brown, greenish-grey, or yellow.
[edit] Venom
Death adders inject on average 40 – 100 mg of extremely toxic venom (0.4 – 0.5 mg/kg murine LD50, subcutaneous) with a bite. This makes an untreated death adder bite one of the most dangerous in the world (rated in top 10 in the CSL list).
Death adder venom is highly neurotoxic. It blocks the post-synaptic neuromuscular transmission from the acetylcholine receptor. Unlike other snakes of its type, it does not contain either procoagulants or myolysins, making treatment easier.
A bite from a death adder causes paralysis. While this paralysis is very minor at first, it can cause death from a complete respiratory shutdown in as little as six hours. Symptoms peak in 24 – 48 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 brain.
Before antivenom was introduced, 50% of death adder bites were fatal. Now, with the antivenom, and due to the slow progression of envenomation symptoms, fatalities from death adder bites are very rare in Australia. In New Guinea, deaths from these snakes are still common.
[edit] Taxonomy
Although the death adder appears to be a viper, of the Viperidae family, it is really a member of the Elapidae family, being more closely related to cobras, mambas, and coral snakes.
The three best known species of death adders (genus Acanthophis) are:
- Death Adder or Common Death Adder — Acanthophis antarcticus
- Northern Death Adder — Acanthophis praelongus
- Desert Death Adder — Acanthophis pyrrhus
Some of these species have been split into more than one and others have been discovered and named.
The word "Acanthophis" means "Spine snake", referring to the spine on the Death adder's tail.
[edit] References
- The Reptilian Magazine; Volume 3, number 4, pp. 7-21 and Volume 3, number 5, pp. 27-34.
[edit] External links
- Death Adder Taxonomy - Family Elapidae
- A severe case of stomatitis (canker or mouthrot) in a Death Adder (Acanthophis antarcticus) associated with a reovirus infection.
Boydii (Autumn 2004):16-17. Treatment
lt:Mirtinosios gyvatės nl:Noordelijke doodsadder ja:トゲオマムシ no:Acanthophis pl:Zdradnica śmiercionośna ru:Смертельные змеи
