Comments on the relationships of the North American cave fishes of the family Amblyopsidae. American Museum novitates ; no. 2109

Abstract

"During the past half century, the order Cyprinodontiformes (= Microcyprini, Cyprinodontes, Cyprinodontida) was divided into two major groups, the Cyprinodontoidei (typical killifishes) and the Amblyopsoidei (North American cave fishes). Evidence is now presented indicating that these two groups of fishes have been improperly associated taxonomically. On the basis of numerous osteological, myological, and functional features, the amblyopsids are shown to resemble Aphredoderus in considerable detail. Features that appear to unite the amblyopsids and Aphredoderus are found also in Percopsis. Many, though by no means all, of the characters common to amblyopsids and percopsiforms are identified in three gadids, a brotulid, and an ophidiid. The provisional assignment of the Amblyopsidae to a separate order, the Amblyopsiformes, adjoining the Percopsiformes in current classification, is proposed. It is noted parenthetically that the resemblances between these two orders and the Gadiformes and Ophidioidei suggest the existence of a phyletic assemblage in which each group represents a different level of structural organization. Attention is called to the fact that the Amblyopsiformes, Percopsiformes, Gadiformes, and Ophidioidei include forms characteristically inhabiting dim or lightless environments"--P. 33.