The Extinction of the Multituberculates

Abstract

The multituberculate mammals declined in numerical abundance from the late Cretaceous to their extinction in the late Eocene. Their maximal diversity, however, occurred in the late part of the middle Paleocene, suggesting an increase in specialization in the face of competition from placental mammals, which diversified very rapidly in the Paleocene. Various lines of evidence lead to the conclusion that first condylarths, then primates, and finally rodents contributed to the gradual extinction of multituberculates, at least in part by evolution in the same region of competing resource requirements. A phylogeny of the Cenozoic Multituberculata and their ancestors is given, the mammal faunas of the Paleocene are listed by more or less their absolute ages, and the fauna of Bear Creek is analyzed in detail. A theory of replacement of supraspecific taxa is presented and applied.