Annulated sea snake Hydrophis cyanocinctus, photographed by Hanne & Jens Eriksen.

Belongs within: Elapidae.

The Hydrophiinae is a group of sea snakes found in tropical waters of the Indo-Pacific. Members of this group are viviparous, and have a paddle-like tail with elongate neural spines (Naish 2010).

Southern snakes at sea
Published 22 February 2011
Bandy-bandy, Vermicella annulata, either engaged in an alarm display or participating in a game of croquet. Photo from here.

The front-fanged snakes are a distinctive clade distinguished, as it says on the label, by their well-developed venom-injecting fangs at the front of the mouth. For a long time, the front-fanged snakes were treated as two families, the terrestrial Elapidae and the sea snakes of the Hydrophiidae. However, it has become well-established that the sea snakes are derived from within the Elapidae, and ‘Hydrophiidae’ became the elapid subfamily Hydrophiinae. As well as its original quota of sea snakes, the Hydrophiinae also now includes the Australo-Papuan species of terrestrial Elapidae. The sea snakes, as it turns out, are not monophyletic within the Hydrophiinae: the sea kraits of the genus Laticauda form the sister group to other hydrophiines, while the remaining sea snakes form a deeply-nested clade (the Hydrophiini) within the terrestrial hydrophiines (Sanders et al. 2008).

Yellow-lipped sea krait Laticauda colubrina, from here.

Sea kraits differ from hydrophiin sea snakes in that they still spend part of their lives on land. They hunt and feed aquatically, mostly on eels, with females catching larger, deeper-living prey than males and juveniles (Shine & Shetty 2001). However, after feeding they tend to return to land to digest their prey. Sea kraits also mate and lay their eggs on land. One possible exception has been claimed for the Rennell Island sea krait Laticauda crockeri which, being restricted to an brackish inland lake on Rennell Island in the Solomons, is also one of the few freshwater sea kraits. Laticauda crockeri has never been recorded on land, and the local people claim that it produces live young, reporting that young can be found within females. In contrast, a sympatric population of the more widespread yellow-lipped sea krait L. colubrina is correctly reported by Rennell Islanders as a terrestrial egg-layer. Unfortunately, Cogger et al. (1987) failed to collect gravid females in their study of L. crockeri and were unable to confirm the local reports.

Yellow-bellied sea snake Pelamis platurus photographed off Costa Rica by Zoltan Takacs.

Hydrophiins, in contrast, are truly marine, bearing live young and unable to move on land. Both sea kraits and hydrophiins have deep paddle-shaped tails, but the tail of hydrophiins differs from that of sea kraits in being supported by extensions of the vertebral apophyses. Sea snakes are widely recognised as among the most venomous of living snakes, but are also known as mostly unlikely to bite humans (different species, of course, exhibit different levels of agression); sea snakes do not even necessarily inject venom when they do bite (Senanayake et al. 2005). Two notable exceptions to the high venom strength of most sea snakes are the marbled sea snake Aipysurus eydouxii and the turtle-head sea snake Emydocephalus annulatus, both specialist feeders on fish eggs. Fish eggs, of course, do not tend to put up much of a fight, and the venom strength of these species is less than one-fiftieth that of other sea snakes (Li et al. 2005). They also have reduced fangs and poison glands, but on the other hand they do have stronger throat muscles (improving their suction).

Western brown snake Pseudonaja mengdeni, photographed by Dan Lynch.

Among the terrestrial hydrophiines, the Hydrophiini are most closely related to a clade of viviparous species including, among others, the tiger snakes Notechis and the Australian copperheads Austrelaps (Sanders et al. 2008). The origin of viviparity in Hydrophiinae remains unsettled. Scanlon & Lee (2004) found support, albeit low, for a single viviparous clade, but Sanders et al. (2008) found three independent viviparous clades—the large-bodied viviparous clade just mentioned, a second clade of smaller snakes such as the ornamental snakes Denisonia and the hooded snakes Suta, and the death adders Acanthophis as a third clade—but were unable to significantly reject monophyly. Similarly, Scanlon & Lee (2004) posited a single origin for burrowing hydrophiines such as the Vermicella pictured at the top of this post (a specialised predator of Typhlopidae blind snakes), but Sanders et al. (2008) supported two separate clades with Vermicella distant from other burrowing taxa. One thing they did agree on was a close relationship between the brown snakes Pseudonaja and the taipans Oxyuranus.

Offhand, in case anyone was hoping that a post on elapids might lead me to a discussion of the… ahem… works of one Raymond Hoser: at one point, I would indeed have happily delved into the subject. But I have to confess that, as time marches on, I find myself increasingly sympathetic to C. T. Simpson’s dismissal of the Nouvelle École: “Life is too short and valuable to be wasted in any attempt at deciphering such nonsense“.

Systematics of Hydrophiinae
<==Hydrophiinae [Hydrophiidae]
    |--Hydrus platurus [incl. Pelamis bicolor]R13
    |--Echiopsis Fitzinger 1843C18
    |    `--E. curta (Schlegel 1837)C18
    |--Paroplocephalus Keogh, Scott & Scanlon 2000C18
    |    `--P. atriceps (Storr 1980)C18
    |--Tropidechis Günther 1863C18
    |    `--T. carinatus (Krefft 1863)C18
    |--Acalyptophis Boulenger 1896C18
    |    `--A. peronii (Duméril 1853)C18
    |--Astrotia Fischer 1856C18
    |    `--A. stokesii (Gray 1846)C18
    |--Emydocephalus Krefft 1869C18
    |    `--E. annulatus Krefft 1869C18
    |--Enhydrina Gray 1849C18
    |    `--E. zweifeli Kharin 1985C18
    |--Ephalophis Smith 1931C18
    |    `--E. greyae Smith 1931C18
    |--Hydrelaps Boulenger 1896C18
    |    `--H. darwiniensis Boulenger 1896C18
    |--Lapemis Gray 1835C18
    |    `--L. curtus Gray 1835 [incl. L. hardwickii]C18
    |--Parahydrophis Burger & Natsuno 1974C18
    |    `--P. mertoni (Roux 1910)C18
    |--Pelamis Daudin 1803C18
    |    `--P. platura (Linnaeus 1766)C18
    |--Rhinoplocephalus Müller 1885C18
    |    |--R. bicolor Müller 1885C18
    |    `--R. monachusSH90
    |    |--P. colubrinus [incl. P. fasciatus]R13
    |    `--P. laticaudatus [incl. P. fischeri]R13
    |--Antaioserpens Wells & Wellington 1984C18
    |    |--A. albiceps (Boulenger 1898)C18
    |    `--A. warro (De Vis 1884)C18
    |--Elapognathus Boulenger 1896C18
    |    |--E. coronatus (Schlegel 1837)C18
    |    `--E. minor (Günther 1863)C18
    |--Hemiaspis Fitzinger 1860C18
    |    |--H. damelii (Günther 1876)C18
    |    `--H. signata (Jan 1859)C18
    |--Neelaps Günther 1863C18
    |    |--N. bimaculatus (Duméril, Bibron & Duméril 1854)DH08
    |    `--N. calonotus (Duméril, Bibron & Duméril 1854)C18 (see below for synonymy)
    |--Glyphodon Günther 1858C18
    |    |--G. dunmalli (Worrell 1955) [=Furina dunmalli]C18
    |    `--G. tristis (Günther 1858) [=Furina tristis]C18
    |--Austrelaps Worrell 1963C18
    |    |--A. labialis (Jan 1859)C18
    |    |--A. ramsayi (Krefft 1864)C18
    |    `--A. superbus (Günther 1858)C18
    |--Drysdalia Worrell 1961C18
    |    |--D. coronoides (Günther 1858)C18
    |    |--D. mastersii (Krefft 1866)C18
    |    `--D. rhodogaster (Jan & Sordelli 1873)C18
    |--Furina Duméril 1853C18
    |    |--F. barnardi (Kinghorn 1939)C18
    |    |--F. diadema (Schlegel 1837)C18
    |    `--F. ornata (Gray 1842)C18
    |--Cacophis Günther 1863C18
    |    |--C. churchilli Wells & Wellington 1985C18
    |    |--C. harriettae Krefft 1869C18
    |    |--C. krefftii Günther 1863C18
    |    `--C. squamulosus (Duméril, Bibron & Duméril 1854)C18
    |--Simoselaps Jan 1859C18
    |    |--S. anomalus (Sternfeld 1919)C18
    |    |--S. bertholdi (Jan 1859)C18
    |    |--S. littoralis (Storr 1968)ADD08
    |    `--S. minimus (Worrell 1960)C18
    |--Suta Worrell 1961C18
    |    |--S. fasciata Rosén 1905C18
    |    |--S. ordensis (Storr 1984)C18
    |    |--S. punctata (Boulenger 1896)C18
    |    `--S. suta (Peters 1863)C18
    |--Cryptophis Worrell 1961C18
    |    |--C. boschmai (Brongersma & Knaap-van Meeuwen 1961)C18
    |    |--C. incredibilis (Wells & Wellington 1985)C18
    |    |--C. nigrescens (Günther 1862)C18
    |    |--C. nigrostriatus (Krefft 1864)C18
    |    `--C. pallidiceps (Günther 1858)C18
    |--Oxyuranus Kinghorn 1923C18
    |    |--O. microlepidotus (McCoy 1879)C18
    |    |--O. scutellatus (Peters 1867)C18
    |    |    |--O. s. scutellatusC18
    |    |    `--O. s. canniC18
    |    `--O. temporalis Doughty, Maryan et al. 2007C18
    |--Acanthophis Daudin 1803C18
    |    |--A. antarcticus (Shaw & Nodder 1802)C18
    |    |--A. hawkei Wells & Wellington 1985C18
    |    |--A. lancasteri Wells & Wellington 1985 [incl. A. cryptamydros Maddock, Ellis et al. 2015]C18
    |    |--A. praelongus Ramsay 1877C18
    |    |--A. pyrrhus Boulenger 1898C18
    |    |--A. rugosus Loveridge 1948C18
    |    `--A. wellsei Hoser 1998C18
    |--Hoplocephalus Wagler 1830C18
    |    |--H. ater Krefft 1866K66
    |    |--H. bitorquatus (Jan 1859)C18
    |    |--H. bungaroides (Schlegel 1837)C18
    |    |--H. collaris Macleay 1887M87
    |    |--H. frontalis Ogilby 1890O90
    |    |--H. gouldii Krefft 1866K66
    |    |--H. mastersii Krefft 1866K66
    |    `--H. stephensii Krefft 1869C18
    |--Notechis Boulenger 1896C18
    |    `--N. scutatus (Peters 1861)C18
    |         |--N. s. scutatusC18
    |         |--N. s. aterC18
    |         |--N. s. humphreysiC18
    |         |--N. s. nigerC18
    |         |--N. s. occidentalisC18
    |         `--N. s. serventyiC18
    |--Denisonia Krefft 1869C18
    |    |--D. carpentariaeF13
    |    |--D. coronataG54
    |    |--D. coronoidesG54
    |    |--D. devisi Waite & Longman 1920C18
    |    |--D. fasciataSH90
    |    |--D. maculata (Steindachner 1867)C18
    |    |--D. nigrescensF13
    |    `--D. superbaD56
    |--Parasuta Worrell 1961C18
    |    |--P. flagellum (McCoy 1878)C18
    |    |--P. gouldii (Gray 1841)C18
    |    |--P. monachus (Storr 1964)C18
    |    |--P. nigriceps (Günther 1863)C18
    |    `--P. spectabilis (Krefft 1869)C18
    |         |--P. s. spectabilisC18
    |         |--P. s. bushiC18
    |         |--P. s. dwyeriC18
    |         `--P. s. nullarborC18
    |--Pseudonaja Günther 1858C18
    |    |--P. affinis Günther 1872C18
    |    |--P. aspidorhyncha (McCoy 1879)C18
    |    |--P. guttata (Parker 1926)C18
    |    |--P. inframacula (Waite 1925)C18
    |    |--P. ingrami (Boulenger 1908)C18
    |    |--P. mengdeni Wells & Wellington 1985C18
    |    |--P. modesta (Günther 1872)C18
    |    |--P. nuchalis Günther 1858C18
    |    `--P. textilis (Duméril, Bibron & Duméril 1854)C18
    |--Vermicella Günther 1858C18
    |    |--V. annulata (Gray 1841)C18
    |    |--V. approximansSH90
    |    |--V. bertholdiSH90
    |    |--V. bimaculataSH90
    |    |--V. fasciolataSH90
    |    |--V. intermedia Keogh & Smith 1996C18
    |    |--V. littoralisSH90
    |    |--V. multifasciata (Longman 1915)C18
    |    |--V. snelli Storr 1968C18
    |    `--V. vermiformis Keogh & Smith 1996C18
    |--Aipysurus Lacépède 1804C18
    |    |--A. apraefrontalis Smith 1926C18
    |    |--A. annulatus [incl. A. chelonicephalus]R13
    |    |--A. duboisii Bavay 1869C18
    |    |--A. eudouxii (Gray 1849)C18
    |    |--A. foliosquama Smith 1926C18
    |    |--A. fuscus (Tschudi 1837)C18
    |    |--A. laevis Lacépède 1804C18 [incl. A. fuliginosusR13]
    |    |--A. mosaicus Sanders, Rasmussen et al. 2012C18
    |    |--A. pooleorum Smith 1974C18
    |    `--A. tenuis Lönnberg & Andersson 1913C18
    |--Brachyurophis Günther 1863C18
    |    |--B. approximans (Glauert 1954)C18
    |    |--B. australis (Krefft 1864)C18
    |    |--B. campbelli (Kinghorn 1929)C18
    |    |--B. fasciolatus (Günther 1872)C18
    |    |    |--B. f. fasciolatusC18
    |    |    `--B. f. fasciatusC18
    |    |--B. incinctus (Storr 1968)C18
    |    |--B. morrisi (Horner 1998)C18
    |    |--B. roperi (Kinghorn 1931) [=Simoselaps roperi]C18
    |    `--B. semifasciatus Günther 1863C18
    |--Pseudechis Wagler 1830C18
    |    |--P. australis (Gray 1842)C18
    |    |--P. butleri Smith 1982C18
    |    |--P. colletti Boulenger 1802C18
    |    |--P. guttatus De Vis 1905C18
    |    |--P. mortonensisF13
    |    |--P. pailsei (Hoser 1998)C18
    |    |--P. papuanus Peters & Doria 1878C18
    |    |--P. porphyriacus (Shaw 1794)C18
    |    |--P. rossignoliiC18
    |    `--P. weigeli Wells & Wellington 1987C18
    |--Demansia Günther 1858C18
    |    |--D. angusticeps (Macleay 1888)C18
    |    |--D. calodera Storr 1978C18
    |    |--D. flagellatio Wells & Wellington 1985C18
    |    |--D. nuchalisG54
    |    |    |--D. n. nuchalisG54
    |    |    `--D. n. affinisG54
    |    |--D. olivacea (Gray 1842)C18
    |    |--D. papuensis (Macleay 1877)C18
    |    |    |--D. p. papuensisC18
    |    |    `--D. p. melaenaC18
    |    |--D. psammophis (Schlegel 1837)C18
    |    |    |--D. p. psammophisADD08
    |    |    `--D. p. cupreicepsADD08
    |    |--D. quaesitor Shea 2007C18
    |    |--D. reticulata (Gray 1842)C18 [=D. psammophis reticulataADD08]
    |    |--D. rimicola Scanlon 2007C18
    |    |--D. rufescens Storr 1978C18
    |    |--D. shinei Shea 2007C18
    |    |--D. simplex Shea 1978C18
    |    |--D. textilisF13
    |    |--D. torquata (Günther 1862)C18
    |    `--D. vestigiata (De Vis 1884)C18
    `--Hydrophis Sonnini & Latreille 1802 [incl. Disteira]C18
         |--H. atriceps Günther 1864C18
         |--H. belcheri (Gray 1849)C18
         |--H. caerulescens (Shaw 1802)C18
         |--H. coggeri (Kharin 1984)C18
         |--H. cyanocinctusN10
         |--H. czeblukovi (Kharin 1984)C18
         |--H. donaldi Ukuwela, Sanders & Fry 2012C18
         |--H. elegans (Gray 1842)C18
         |--H. fasciatusB00
         |--H. gracilis (Shaw 1802)C18
         |--H. inornatus (Gray 1849)C18
         |--H. kingii Boulenger 1896C18
         |--H. laboutei Rasmussen & Ineich 2000C18
         |--H. macdowelli Kharin 1983C18
         |--H. major (Shaw 1802)C18 [=Distira majorR13; incl. H. protervusR13]
         |--H. melanosoma Günther 1864C18
         |--H. ornatus (Gray 1842)C18
         |--H. pacificus Boulenger 1896C18
         |--H. rhombifer Boulenger 1900B00
         |--H. semperiN10
         |--H. sibauensis Rasmussen et al. 2001N10
         |--H. spiralisN10
         |--‘Distira’ tuberculataB00
         |--H. vorisi Kharin 1984C18
         `--‘Distira’ wrayi Boulenger 1900B00

Neelaps calonotus (Duméril, Bibron & Duméril 1854)C18 [=Furina calonotaR13; incl. N. caledonicusR13, N. neocaledonicusR13]

*Type species of generic name indicated


[ADD08] Aplin, K., S. Donnellan & J. Dell. 2008. The herpetofauna of Faure Island, Shark Bay, Western Australia. Records of the Western Australian Museum Supplement 75: 39–53.

[B00] Boulenger, G. A. 1900. Descriptions of new reptiles from Perak, Malay Peninsula. Annals and Magazine of Natural History, series 7, 5: 306–308.

[C18] Cogger, H. G. 2018. Reptiles and Amphibians of Australia updated 7th ed. CSIRO Publishing: Collingwood.

Cogger, H., H. Heatwole, Y. Ishikawa, M. McCoy, N. Tamiya & T. Teruuchi. 1987. The status and natural history of the Rennell Island sea krait, Laticauda crockeri (Serpentes: Laticaudidae). Journal of Herpetology 21 (4): 255–266.

[D56] Dawes, B. 1956. The Trematoda with special reference to British and other European forms. University Press: Cambridge.

[DH08] Doughty, P., & M. N. Hutchinson. 2008. A new species of Lucasium (Squamata: Diplodactylidae) from the southern deserts of Western Australia and South Australia. Records of the Western Australian Museum 25 (1): 95–106.

[F13] Fry, D. B. 1913. On a Varanus and a frog from Burnett River, Queensland, and a revision of the variations in Limnodynastes dorsalis, Gray. Records of the Australian Museum 10 (2): 17–34, pls 1–3.

[G54] Glauert, L. 1954. Reptiles and frogs. In: Willis, J. H. (ed.) The Archipelago of the Recherche pp. 29–35. Australian Geographical Society: Melbourne.

[K66] Krefft, G. 1866. Descriptions of three species of snakes of the genus Hoplocephalus. Proceedings of the Zoological Society of London 1866: 370–371.

Li, M., B. G. Fry & R. M. Kini. 2005. Eggs-only diet: its implications for the toxin profile changes and ecology of the marbled sea snake (Aipysurus eydouxii). Journal of Molecular Evolution 60: 81–89.

[M87] Macleay, W. 1887. Description of a new species of Hoplocephalus. Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 1111–1112.

[N10] Naish, D. 2010. Tetrapod Zoology: Book One. CFZ Press: Bideford (UK).

[O90] Ogilby, J. D. 1890. Description of a new snake belonging to the genus Hoplocephalus. Proceedings of the Linnean Society of New South Wales, series 2, 4 (3): 1027–1028.

[R13] Roux, J. 1913. Les reptiles de la Nouvelle-Calédonie et des îles Loyalty. In: Sarasin, F., & J. Roux (eds) Nova Caledonia: Forschungen in Neu-Caledonian und auf den Loyalty-Inseln. A. Zoologie vol. 1 pt 2 pp. 79–160. C. W. Kreidels Verlag: Wiesbaden.

Sanders, K. L., M. S. Y. Lee, R. Leys, R. Foster & J. S. Keogh. 2008. Molecular phylogeny and divergence dates for Australasian elapids and sea snakes (Hydrophiinae): evidence from seven genes for rapid evolutionary radiations. Journal of Evolutionary Biology 21 (3): 682–695.

Scanlon, J. D., & M. S. Y. Lee. 2004. Phylogeny of Australasian venomous snakes (Colubroidea, Elapidae, Hydrophiinae) based on phenotypic and molecular evidence. Zoologica Scripta 33 (4): 335–366.

Senanayake, M. P., C. A. Ariaratnam, S. Abeywickrema & A. Belligaswatte. 2005. Two Sri Lankan cases of identified sea snake bites, without envenoming. Toxicon 45 (7): 861–863.

Shine, R., & S. Shetty. 2001. Moving in two worlds: aquatic and terrestrial locomotion in sea snakes (Laticauda colubrina, Laticaudidae). Journal of Evolutionary Biology 14: 338–346.

[SH90] Storr, G. M., & G. Harold. 1990. Amphibians and reptiles of the Shark Bay area, Western Australia. In: Berry, P. F., S. D. Bradshaw & B. R. Wilson (eds) Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee pp. 279–285. Western Australian Museum.

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