Four familial or subfamilial marsupial taxa that are represented in Late Cretaceous deposits of Bolivia and Peru (pediomyids, caroloameghiniids, and didelphine and eobrasiliine opossums) are also found in the medial Paleocene, Itaborai Local Fauna of Brazil. The Itaborai Local Fauna contains five additional taxa: derorhynchine didelphids, protodidelphids, borhyaenenids, polydolopids, and
... [Show full abstract] microbiotheriids. The diversity of this fauna is of such taxonomic breadth that a Late Cretaceous origin for this South American marsupial radiation appears likely. Thus, the number of South American marsupial taxa at all levels that transgressed this boundary was greater than that interpreted from the record in North America. Contrary to long-held views based on the North American record, new data suggest that marsupials survived the end of the Cretaceous and passed into the Tertiary in increasing numbers in the South American region.-from Authors