Metatérios do Início do Paleógeno no Brasil: Diversidade e Afinidades

OLIVEIRA EV; GOIN FJ

Os Marsupiais do Brasil: Biologia, Ecologia e Conservação. (2º ed.)

Editora UFMS

Lugar: Campo Grande; Año: 2012; p. 275 - 307

The diversity of the latest Paleocene-early Eocene metatherian fauna of Itaboraí locality, Brazil, is presented. Almost all major lineages (orders) of South American Cenozoic marsupials are already present in the Itaboraí fauna:Sparassodonta (Borhyaenoidea), Pediomyidae, Peradectoidea, ?Didelphimorphia?, Paucituberculata, and Polydolopimorphia. Recent studies exclude the Microbiotheria of the Itaboraí fauna. North American lineages are represented by pediomyids and a few peradectids. The caroloameghiniid opossums represent a South American peradectoid lineage. Sparassodonts include small, generalized forms such as Patene, whose overall dental morphology, suggest that their origin is not from didelphimorphians but from peradectid or peradectid-like metatherians. The large variety of Itaboraian ?didelphimorphians? (a polyphyletic clade in its present concept) include, among others, eobrasilines, herpetotheriids (sternbergiines and derorhynchines), monodelphopsines, pucadelphyids and the specialized protodidelphids; most of them seem to belong to early metatherian clades an early clade of metatherians, not closely related to modern (Neogene) didelphid opossums. Derorhynchines have several derived dental features suggesting affinities with Australian peramelemorphians. One of the oldest known Paucituberculata is also recorded in the Itaboraí fauna. Polydolopimorphians were supposed to be exclusively represented in Itaboraí by epidolopines; however, Bobbschaefferia and Mirandatherium may constitute early, plesiomorphic polydolopimorphians, are discussed. Even though North American in origin, South American taxa, especially the Paleocene-Eocene ones, seem to be key for the interpretation of the African, Eurasian, Antarctic, and Australian radiations of metatherians.