Two perspectives on the evolution of the tetrapod limb

Abstract

SYNOPSIS. The evolution of the tetrapod limb is examined from two perspectives: structural and functional. Rosen et al. (1981) argued that lungfishes are the sister group of tetrapods, with limb characteristics comprising an important subset of their evidence. A re-analysis of the limb characters advocated by Rosen et al. does not support their contention, but instead suggests that rhipidistian fishes of the family Osteolepidae are the closest relatives of the tetrapods. In order to understand the probable selective pressures leading to evolution of the tetrapod limb, a functional analysis of the fins of antennariid anglerfishes was performed. Antennariids use their limb-like fins to traverse underwater substrates. The analysis reveals a large number of functional and morphological convergences between antennariid fins and tetrapod limbs. It is suggested that tetrapod limbs were evolved for underwater transport rather than for locomotion on dry land. © 1989 by the American Society of Zoologists.