The Development of the Teleost Fin and Implications for Our Understanding of Tetrapod Limb Evolution

Abstract

Elsewhere in this volume are accounts of how the study of adult fins and limbs of extinct, putatively ancestral, vertebrates might reveal the inherent constraints of developmental programmes underlying vertebrate fin and limb formation. Moreover, evolutionary morphologists postulate that phenotypic range within these vertebrate forms reveals ‘permissive’ variation within such developmental programmes (see papers by Coates and Vorobyeva, this volume) . Here I wish to complement that approach by proposing that study of embryonic development of the paired fins in extant fishes can elucidate how variation of adult phenotype in extinct and ancestral forms might have been generated. It is also worth stating at this point that the development of fin buds, unlike that of tetrapod limb buds, has been a grossly neglected area of developmental biology, which is somewhat surprising given the consistent interest in origin and evolution of the tetrapod limb by developmentalists and evolutionists alike. Of the limited work published, much of it concerns the development of the paired fins of actinopterygian teleosts and the brief account which follows is confined to the general and common features described for the small number of species studied to date (namely, Salmo species, Aphyosemion scheeli, Barbus conchonius and Brachydanio rerio).