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McCarthy, C. J. (1982) The relationships of the laticaudine sea snakes (family elapidae genus laticuada). Doctoral thesis, City of London Polytechnic.
The genus Laticauda is regarded by some workers as the most primitive member of the sea snake family Hydrophiidae. However others consider that Laticauda and "true" sea snakes (Hydrophiinae) are more likely to have had separate origins within the front-fanged "proteroglyphous" snakes (Elapidae); laticaudines are thought to be most closely allied to a group comprising terrestrial Asiatic and American coral snakes together with a Solomon Islands (Bougainville) endemic proteroglyph.
The present study of laticaudine affinities is divided into three main parts:-
1) An introductory section reviews the theory supporting the analytical methods used, considers some of the biological and distributional aspects of the Elapidae sensu lato and examines current theories of relationships within the "family".
2) A wide range of external and internal anatomical features of a variety of elapids are described and states of these characters are arranged into most likely transformation series, attempts also being made to determine polarities (primitive and derived conditions).
3) In the analysis and discussion section three topics are considered:-
a) The issue of monophyly of the family Elapidae is examined and a recent proposal that New World proteroglyphs represent an independent derivation from American colubrids is rejected on the basis of critical re-evaluation of the evidence alleged to support the theory.
b) Intra- and inter-specific variation in Laticauda is described.
c) A sample of fifteen elapid species for 89 binary characters is analysed using several numerical techniques (i.e. phenetic, compatibility and parsimony methods). The main conclusion is that although the data, with most forms of analysis, tends to support the theory that the closest allies of Laticauda are some hydrophiine sea snakes, there is a considerable amount of conflicting information. It is suggested that this uncertain situation is best reflected in a classification which treats Laticaudinae, Hydrophiinae and Elapinae as equivalent subfamilies of the Elapidae.
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