Cenozoic Metatherian Evolution in the Americas

GOIN FJ

American and Australasian Marsupials: an evolutionary, biogeographical, and ecological approach

Springer

Lugar: Cham; Año: 2022;

The evolution of Cenozoic metatherians was quite different in North and South America. In the former, they underwent impressive radiations during the Late Cretaceous (concomitant with the event known as Cretaceous Terrestrial Revolution, or KTR). Immediately after the Cretaceous-Paleogene boundary, North American metatherians declined by two thirds, and their Cenozoic history was that of impoverished associations, always subordinated to those of eutherians. By mid Miocene times they were extinct, only to come back in Quaternary times, from South America, as part of the event known as GABI (Great American Biotic Interchange). In South America, metatherians probably arrived by the latest Cretaceous-earliest Paleocene (Maastrichtian-Danian), in a biotic event known as FABI (First American Biotic Interchange). They underwent a rapid diversification already by early Paleocene times, and had an impressive adaptive radiation, as well as their diversity climax, by the late Paleocene-Early Eocene (by that time, two thirds of all therian taxa in this continent were metatherians). At some time during the Paleocene metatherians arrived to Antarctica from where they dispersed into Australasia, probably prior to the Eocene. The Cenozoic history of South American metatherians is fully understandable when contextual aspects are considered: tectonics, global climates, and biogeography.