Hydrophis inornatus Gray, 1849

Plain sea snake



Taxonomy & Nomenclature

Synonym/s: Chitulia inornata Gray, 1849


This species may be invalid (Elfes et al., 2013).


According to the dichotomous key provided by (Rasmussen, 2001), the Plain sea snake ([i]Hydrophis inornatus[/i]) exhibits the following unique combination of characters:

* "Localit[y] different from Lake Taal in Luzon, Philippines" (paraphrasing)

* "Ventrals normally entire and distinct throughout"

* "At least 22 scale rows around neck"

* "Less than 14 maxillary teeth behind the poison-fangs"

* "At least 5 maxillary teeth behind the poison-fangs"

* "At least 37 scale rows around neck"

* "Dorsal part of body with parallel bands anteriorly and normally the interspaces 2 or less scales wide, and/or 42 bands or more on body and tail"

* "Less than 275 ventrals; more than 29 scale rows around neck"

* "Bands on body 38 or more, and/or 10 or more maxillary teeth behind the poison fangs"

* "Less than 280 ventrals; more than 36 scale rows around body"

* "Scale rows around neck 30 or more, and/or body without 2 or 3 series of spots or dark-edged markings"

* "More than 49 scale rows around body; less than 8 maxillary teeth behind the poison fangs"

* "Number of ventrals less than 280 or more than 330; no rows of regular black pentagonal markings on side of body"

* "At least 9 maxillary teeth behind the poison-fangs"

* "More than 27 scale rows around neck; more than 1 postocular"

* "Body grey above, white below"


Conservation Status

Missing or invalid (Elfes et al., 2013)

Last (and only) record: 1849 or before; 1849 (Martin et al., 2023)

IUCN status: Data Deficient


The Plain sea snake (Hydrophis inornatus) is only known from a single specimen collected some time before 1849.



"Indian Ocean"


Biology & Ecology




Holotype: USNM 38585


The Plain sea snake (Hydrophis inornatus) is only known from a single specimen collected some time before 1849.






Original scientific description:

Gray, J. E. (1849). Catalogue of the Specimens of Snakes in the Collection of the British Museum. London: British Museum, 125 pp.


Other references:

Cogger, H.G. (1975) Sea Snakes of Australia and New Guinea. In: Dunson, W.A. (Ed.), The Biology of Sea Snakes. University Park Press, Baltimore London & Tokyo, pp. 59-139.

Elfes, Cristiane T. et al. (2013). Fascinating and forgotten: the conservation status of marine elapid snakes. Herpetological Conservation and Biology 8(1): 37-52.

Kharin, V. E. and Czeblukov, V.P. (2005) On the new Record of rare sea snakes Chitulia inornata Gray, 1849 (Serpentes: Hydrophiidae) from Australia Russian Journal of Herpetology 12: 118-120.

Kharin, V. E. and Dotsenko, I. B. (2012). The First Record of the Sea Snake Chitulia inornata Gray, 1849 from the Arabian Sea with Notes on the Composition of the Genus Chitulia Gray, 1849 (Serpentes: Hydrophiidae). Russian Journal of Marine Biology 38: 35-42.

Martin, Thomas E., Bennett, Gareth C., Fairbairn, Andrew J. and Mooers, A. Ø. (2023). ‘Lost’ taxa and their conservation implications. Animal Conservation 26(1): 14-24. [Appendix S2 (1617 taxa not seen >10 years); Appendix S3 (562 taxa not seen >50 years)]

Rasmussen, A. R. (1989). An analysis of Hydrophis ornatus (Gray), H. lamberti Smith, and H. inornatus (Gray) (Hydrophiidae, Serpentes) based on samples from carious localities, with remarks on feeding and breeding biology of H. ornatus. Amphibia-Reptilia 10: 397-417.

Rasmussen, A. R. (2001). Sea snakes. In: Carpenter, K.E. and Niem, V.H. (Eds.) Living Marine resources of the Western central Pacific. Food and Agriculture Organization, Rome, pp. 3987-4000. [Available from: www[dot][dot]pdf]

Rasmussen, A. (2009). Hydrophis inornatus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. ( Downloaded on 11 September 2011.

Rasmussen, Arne Redsted, Sanders, Kate Laura, Guinea, Michael L. and Amey, Andrew P. (2014). Sea snakes in Australian waters (Serpentes: subfamilies Hydrophiinae and Laticaudinae)—a review with an updated identification key. Zootaxa 3869(4): 351-371.

Regalado, Pedro Galán. (2015). Los Anfibios y Reptiles Extinguidos: Herpetofauna Desaparecida Desde el Año 1500. Monografías de la Universidade da Coruña 155: 1-509.

Smith, M. A. (1926). Monograph of the sea-snakes (Hydrophiidae). Printed by order of the Trustees of the British museum (Natural History) London, 130 pp.


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