Late Cenozoic Freshwater Fishes of North America

Abstract

slower than changes in geography and climate, and there­ fore we cannot assume that fishes have recently adapted to the environments and climates in 'Which they presently live. The scope of this review includes freshwater fishes in North America north of Mexico in Miocene, Pliocene, and Pleistocene sedimentary rocks. I emphasize middle-latitude faunas, which are better known and have richer fossil representation than those of glaciated latitudes. Fossil fishes preserved in freshwater deposits are conveniently separated both ecologically and, for the most part, phylogenetically from those in marine environments with little ambiguity. The dominant families of freshwater fishes in the late Cenozoic of North America are the gars (Lepisosteidae), trouts and salmon (Salmonidae), pikes (Esocidae), minnows (Cyprinidae), suckers (Catos­