Sea kraits are a genus of venomous elapidsea snakes (subfamily: Laticaudinae), Laticauda. They are semiaquatic, and retain the wide ventral scales typical of terrestrial snakes for moving on land, but also have paddle-shaped tails for swimming.[1] Unlike fully aquatic ovoviviparous sea snakes, sea kraits are oviparous and must come to land to digest prey and lay eggs.[2] They also have independent evolutionary origins into aquatic habitats, with sea kraits diverging earlier from other Australasianelapids.[3][4] Thus, sea kraits and sea snakes are an example of convergent evolution into aquatic habitats within the Hydrophiinae snakes. Sea kraits are also often confused with land kraits (genus Bungarus), which are not aquatic.
Sea kraits are semiaquatic, so have morphologicaladaptations to both land and sea. Laticaudaspecies show traits intermediate between those of sea snakes and terrestrial elapids. They have a vertically flattened and paddle-shaped tail (similar to sea snakes) and laterally positioned nostrils and broad, laterally expanded ventral scales (similar to terrestrial elapids).[1][5][6] Their body has a striped pattern, nasal scales are separated by inter-nasals scales, and the maxillary bone extends forwards beyond the palatine bone.[2] Members of Laticauda can grow to 1.5 m (4.9 ft) long.[7]
Laticauda species are found throughout the South and Southeast Asian islands spreading from India in the west, north as far as Japan, and southeast to Fiji. They occasionally wander south to the Eastern coast of Australia and New Zealand (Laticauda colubrina being the most common example in New Zealand), however no known locally breeding populations are known to exist in these areas.[8] Sea kraits typically live in the littoral zone of coastal waters and are semi-terrestrial, spending time ashore and in shallow waters, as well as around coral reefs.[8][9]
Laticauda species feed in the ocean, mostly eating moray and conger eels, and some squid, crabs, and fish. They have never been observed feeding on land.
Laticauda species are often active at night, which is when they prefer to hunt. Though they possess highly toxic venom, these snakes are usually shy and reclusive, and in New Caledonia, where they are called tricot rayé ("stripey sweater"), children play with them. Bites are rare, but must be treated immediately. Bites are more likely to occur under low light conditions (night), and when the snake is roughly handled (e.g. grabbed "hard") while in the water, or having been abruptly taken from the water. When these snakes are on land, bites are extremely rare. [10]Black-banded sea kraits, numbering in the hundreds, form hunting alliances with yellow goatfish and bluefin trevally, flushing potential prey from narrow crannies in a reef the same way some moray eels do.[11][12]
Sea kraits are capable of diving up to 80 m deep in a single hunting trip.[13] They also have a very large hunting range, with at least 615 and perhaps up to 1660 km2 surface area for the Blue-lipped sea krait; 1380 and potentially up to 4500 km2 for the New Caledonian sea krait.[14] They have a remarkable ability to climb up vertical rocks of their coastal limestone habitats.[1]
Laticauda females are oviparous, and they return to land to mate and lay eggs.[8] Several males form a mating ball around the female, twitching their bodies in what is termed "caudocephalic waves". Though these animals can occur in high densities in suitable locations, nests of eggs are very rarely encountered, suggesting specific nesting conditions need to be met.
^ abcWilson, Stephen K.; Swan, Gerry (2013). A Complete Guide to Reptiles of Australia. Chatswood, New South Wales: New Holland Publishers. p. 564.
^ abCogger, Hal (2000). Reptiles and Amphibians of Australia. Sydney, NSW: Reed New Holland. p. 722.
^Pyron, R. Alexander; Burbrink, Frank T.; Colli, Guarino R.; de Oca, Adrian Nieto Montes; Vitt, Laurie J.; Kuczynski, Caitlin A.; Wiens, John J. (2011-02-01). "The phylogeny of advanced snakes (Colubroidea), with discovery of a new subfamily and comparison of support methods for likelihood trees". Molecular Phylogenetics and Evolution. 58 (2): 329–342. doi:10.1016/j.ympev.2010.11.006. ISSN1095-9513. PMID21074626.
^Wilson, Don E.; Burnie, David, eds. (2005) [2001]. Animal. London & New York: Dorling Kindersley. ISBN978-0-7894-7764-4.
^"La Lettre de la Délégation n°202". Notes du Centre d'Études Biologiques de Chizé (UPR1934 CNRS) (CNRS DR15) (in French). 202. 2016-03-29. Archived from the original on 2017-03-23. Retrieved 2017-03-23.
^Heatwole H, Busack S, Cogger H (2005). "Geographic variation in sea kraits of the Laticauda colubrina complex (Serpentes: Elapidae: Hydrophiinae: Laticaudini)". Herpetological Monographs19: 1-136.
^Cogger HG, Heatwole HF (2006).『Laticauda frontalis (de Vis, 1905) and Laticauda saintgironsi n.sp. from Vanuato and New Caledonia (Serpentes: Elapidae: Laticaudinae) – a new lineage of sea kraits?』Records of the Australian Museum58: 245-256.
^Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN978-1-4214-0135-5. (Laticauda guineai, p. 112).
^Kharin VE, Czeblukov VP (2006). "A new revision of the sea kraits of family Laticaudidae Cope, 1879 (Serpentes: Colubroidea)". Russian Journal of Herpetology13: 227-241.
^"Sea snake parasites – 1". Tropical Research and Conservation Centre. 8 March 2011. Archived from the original on 2 April 2012. Retrieved 9 October 2017.
Laurenti JN (1768). Specimen medicum, exhibens synopsin reptilium emendatam cum experimentis circa venena et antidota reptilium austriacorum. Vienna: "Joan. Thom. Nob. de Trattnern". 214 pp. + Plates I-V. (Laticauda, new genus, p. 109). (inLatin).
