Pseudonaja

Pseudonaja is a genus of venomous elapid snakes native to Australia. Species of this genus are known commonly as brown snakes and are considered to be some of the most dangerous snakes in the world; even young snakes are capable of delivering a fatal envenomation to a human.

Pseudonaja
Ringed brown snake (P. modesta)
in Northern Territory, Australia
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Elapidae
Subfamily: Hydrophiinae
Genus: Pseudonaja
Günther, 1858

Despite its common name, the king brown snake (Pseudechis australis) is not a brown snake, but a member of the genus Pseudechis, commonly known as black snakes.

Species

These species and subspecies are recognized:[1]

A photo of a dugite taken in Joondalup, Western Australia

N.B: A binomial authority in parentheses indicates that the species was originally described in a genus other than Pseudonaja. Similarly, a trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Pseudonaja.

Venom
An eastern brown snake

Brown snakes accounted for 41% of identified snakebite victims in Australia between 2005 and 2015, with 15 deaths recorded from 296 confirmed envenomations—far more than any other type of snake.[4] Review of snakebite-related deaths in the National Coronial Information System from January 2000 to December 2016 revealed brown snakes were responsible for 23 of 35 deaths.[5]

Brown snakes are easily alarmed and may bite if approached closely, handled, or threatened. Sudden, early collapse is often a symptom of envenomation by them. A prominent effect of envenomation is venom-induced consumption coagulopathy, which can lead to death. Renal damage may also rarely occur.[6]

Other clinical signs include abdominal pain, breathing and swallowing difficulty, convulsions, ptosis, hemolysis, and hypotension from depression of myocardial contractility. Notably, brown snake envenomation does not result in rhabdomyolysis.

The eastern brown snake (Pseudonaja textilis) is the most toxic member of the genus and is considered by some to be the second-most toxic land snake in the world, after the inland taipan (which is also found in Australia). The western brown snake is the 10th-most venomous snake in the world.

Brown snakes can easily harm pet animals and livestock.

The venom fangs of snakes of the genus Pseudonaja are very short, and the average yield of venom per bite is relatively low — for P. textilis, P. nuchalis, and P. affinis, about 4.0 to 6.5 mg dry weight of venom.[7] Therefore, most of the bites end up without serious medical consequences. Despite its toxicity, the smallest Pseudonaja, P. modesta, can even be considered harmless.[7] Bites by the bigger species of Pseudonaja, especially P. textilis and P. nuchalis, are known for causing serious toxicosis and fatalities.

References
  1. "Pseudonaja ". The Reptile Database. www.reptile-database.org.
  2. Skinner, Adam (2009). "A multivariate morphometric analysis and systematic review of Pseudonaja (Serpentes, Elapidae, Hydrophiinae)". Zoological Journal of the Linnean Society. 155: 171–97. doi:10.1111/j.1096-3642.2008.00436.x.
  3. Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Pseudonaja ingrami, p. 130).
  4. Johnston, Christopher I.; Ryan, Nicole M.; Page, Colin B.; Buckley, Nicholas A.; Brown, Simon G.A.; O'Leary, Margaret A.; Isbister, Geoffrey K. (2017). "The Australian Snakebite Project, 2005–2015 (ASP-20)" (PDF). Medical Journal of Australia. 207 (3): 119–25. doi:10.5694/mja17.00094. PMID 28764620. S2CID 19567016.
  5. Welton, R.E.; Liew, D; Braitberg, G. (2017). "Incidence of fatal snake bite in Australia: A coronial based retrospective study (2000-2016)". Toxicon. 131 (11–15): 11–15. doi:10.1016/j.toxicon.2017.03.008. PMID 28288937. S2CID 666851.
  6. Isbister, Geoff; et al. (2006). "Snake Bite: Current Approach to Treatment". Australian Prescriber. 29 (5): 125–129. doi:10.18773/austprescr.2006.078.
  7. Mirtschin PJ, Crowe GR, Davis R (1990). "Dangerous Snakes Of Australia". In: Gopalakrishnakone P, Chou LM (1990). Snakes of Medical Importance. Venom and Toxin Research Group, National University of Singapore. pp. 49–77, especially p. 49.

Further reading
  • Günther A (1858). Catalogue of the Colubrine Snakes in the Collection of the British Museum. London: Trustees of the British Museum. (Taylor and Francis, printers). xvi + 281 pp. (Pseudonaja, new genus, p. 227).
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