Evolution and Dispersal of African Bovidae

Abstract

Shallow water late Precambrian and Early Cambrian sequences have yielded not only shallow water trace fossils but also many examples of traces typical of later deep water deposits. Significant colonization of the deep oceans by trace making animals was, however, delayed until the Early Ordovician. There followed a gradual increase in ichnogeneric diversity through much of the Phanerozoic, with an acceleration from the Cretaceous through the Tertiary. The apparent migration of deep water forms from their origins in shallow water out to the deep sea was accompanied by their virtual disappearance from shallow water, thereby providing an early example of "retreat'. -from Authors