Larval Development and Geographical Distribution of the Indo-West Pacific Murex

While some species of the Indo-West Pacific Murex are distributed over extensive areas, some others are not. Comparison of the present geographical distribution and geological distribution of Murex indicates that the species of older origin are more widely distributed and those of recent origin are more limited. However, existence of some species in the isolated Indo-West Pacific islands cannot be explained by time alone, because Murex should be unable to migrate across bathyal areas due to their lecithotrophic demersal larva development.

A historical change of larval type of Murex from planktotrophic pelagic to lecithotrophic demersal is suggested by a comparison of larval development of Murex with that of Bedevina and other genera of Thaisidinae, Rapaninae and Ergalataxinae, of which the latter group remains of the planktotrophic pelagic type.