DO CORAL-REEF FISH FAUNAS HAVE A DISTINCTIVE TAXONOMIC STRUCTURE

Do the highly diverse fish faunas that associate with coral reefs have distinguishing taxonomic and ecological characteristics, as proposed by Cheat and Bellwood (1991) and Bellwood (1996)? Does a 50 my old (Eo cene) fossil fish fauna from Italy represent a coral-reef fish assembl age that provides unique information about the evolution of such assem blages, as claimed by Bellwood (1996)? I compared the structure of the reef fish faunas of adjacent tropical regions rich and poor in coral reefs, in both America and Polynesia, and found that they exhibit no s ubstantive differences in relative species richness among families of typical ''coral-reef'' fishes. While coral-rich regions have larger re ef fish faunas, a variety of factors probably contribute to such diffe rences. Thus coral-reef fish faunas may lack a distinctive taxonomic s tructure. A similar comparative approach would be useful for assessing whether assemblages of fishes on coral reefs have distinctive ecologi cal characteristics. Based on patterns of habitat use by modern tropic al shorefishes, the Italian Eocene fauna includes few definite reef fi shes, and may well consist primarily of non-reef fishes preserved in a non-reef habitat. Until we know more about the environment in which t hose fossils were preserved, that fauna can contribute little to under standing how coral reef fish assemblages have evolved.