Astrotia stokesii

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Stokes' seasnake
Hydrus Stokesii (Discoveries in Australia).jpg
Hydrus Stokesii (syn. Astrotia stokesii) from John Lort Stokes' 1846 Discoveries in Australia
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Elapidae
Subfamily: Hydrophiinae
Genus: Astrotia
Species: A. stokesii
Binomial name
Astrotia stokesii
(Gray, 1846)

Commonly known as Stokes' seasnake, Astrotia stokesii is a large species of sea snake found in tropical Indo-Pacific oceanic waters.


Stokes' seasnake is one of the heaviest and stoutest seasnakes, with the longest fangs of any marine snake.[2] Its fangs are long enough to pierce a wetsuit.[3] Its mid-ventral scales are enlarged to form a distinct keel on its belly, the keel frequently broken up into two wart-like tubercles.[4] A. stokesii is highly variable in colour,[5] ranging from cream to brown to black, often with broad black dorsal cross bands, or black rings.[6]

Rostral as deep as broad; nasals shorter than the frontal, more than twice as long as the suture between the prefrontals; frontal longer than broad, as long as or slightly longer than its distance from the rostral scale; one pre- and two postoculars, 9 or 10 upper labials, fourth, fifth, and sixth catering the eye, if not divided to form a series of suboculars ; two or three superposed anterior temporals; no chin-shields. 39 to 47 scales round the neck, 48 to 53 round the middle of the body. Ventral scales usually distinct only quite anteriorly, further back in pairs and not larger than the adjoining scales; scales much imbricate, pointed.[6]

Total length 5 feet (1.5 m).


A. stokesii is distributed from Pakistan and Sri Lanka to the South China Sea and Strait of Taiwan. It also lives in all waters of tropical Australia.

Human Interactions[edit]

Although aggressive with a venomous bite, there are no reported human fatalities attributed to Stokes' seasnake.[2]

Stokes' seasnake is captured as bycatch in fisheries, for example in prawn fisheries in Australia.[1]


These snakes sometimes form migrating groups in the thousands, drifting in meter-long slicks in the Strait of Malacca.[2] They are ovoviviparous, producing small broods of five young each mating season.[7]


It was first published as Hydrus stokesii by John Edward Gray in an appendix to Volume 1 of John Lort Stokes' 1846 Discoveries in Australia. It is currently the only member in the monotypic Astrotia genus. In 1972, McDowell resurrected the genus Disteira and merged Astrotia into it, although stokesii lacks the Oxyuranus pattern of venom gland muscle which typifies Disteira, and differs from others in that genus by number of body vertebrae and heart position. Cogger later refused to recognize the placement of stokesii into Disteira.[8]


  1. ^ a b Sanders, K., White, M.-D., Courtney, T. & Lukoschek, V. (2010). "Astrotia stokesii". IUCN Red List of Threatened Species. Version 2012.2. International Union for Conservation of Nature. Retrieved 28 October 2012. 
  2. ^ a b c O'Shea, Mark (2008), Venomous Snakes of the World, New Holland Publishers, p. 144, ISBN 1-84773-086-8 
  3. ^ John A. Williamson, Peter J. Fenner, Joseph W. Burnett, Jacqueline F. Rifkin (1996), Venomous and Poisonous Marine Animals: A Medical and Biological Handbook, UNSW Press, p. 403, ISBN 978-0-86840-279-6 
  4. ^ Harry W. Greene, Patricia Fogden, Michael Fogden (2000), Snakes, University of California Press, p. 236, ISBN 978-0-520-22487-2 
  5. ^ Gopalakrishnakone, P (1994), Sea Snake Toxinology, NUS Press, p. 177, ISBN 978-9971-69-193-6 
  6. ^ a b Boulenger, George Albert (1890), "Reptilia and Batrachia", Fauna of British India (Taylor and Francis) 
  7. ^ Tomascik, Tomas (1997), The ecology of the Indonesian seas, Tuttle Publishing, p. 1140, ISBN 978-962-593-163-0 
  8. ^ Roger S. Thorpe, Wolfgang Wüster, Anita Malhotra (1997), Venomous Snakes: Ecology, Evolution, and Snakebite, Oxford University Press, pp. 15–21, ISBN 978-0-19-854986-4 


  • Cogger,H.G. 2000 Reptiles and Amphibians of Australia, 6th ed. Ralph Curtis Publishing, Sanibel Island, 808 pp.
  • Dunson, William A.;Minton, Sherman A. 1978 Diversity, distribution, and Ecology of Philippine Marine Snakes (Reptilia, Serpentes) Journal of Herpetology 12 (3): 281-286
  • Rasmussen,A.R. 1997 Systematics of sea snakes: a critical review. In: Thorpe,R.S., Wüster,W. & Malhotra,A. (eds.) Venomous snakes - ecology, evolution and snakebite. Clarendon Press (Oxford)/Symp. zool. Soc. Lond. 70: 15-30

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