Movable head armature in higher teleostean fishes

Abstract

A general pattern of movable head armature, composed of serrations on the borders of the lacrimal and preopercle and of a spine on the opercle, evolved among early acanthopterygians and is retained among many basal percoid families. In the more specialized higher teleostean groups this pattern is modified in various ways. Scorpaeniform fishes develop a suborbital stay with which the lacrimal is rigidly united. Elsewhere lacrimal serrations are generally absent, but in some bottom-resting forms preopercular or opercular armature becomes highly specialized. An association between head armature, fin spines, and changes in locomotion in the development of the acanthopterygian state of teleostean evolution is suggested.