The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography.

摘要: We report the discovery of mammalian tribosphenic teeth from basal Cenomanian southwestern France that we refer to a new primitive marsupial-like form identified as taxon Marsupialiformes, clade recognized here include crown group Marsupialia and stem lineages more closely related than Deltatheroida. Arcantiodelphys marchandi gen et sp nov. shares several significant features (s.l.) with marsupialiform taxa known North American Mid-Cretaceous. Among marsupialiforms, it shows closer resemblance Dakotadens. This resemblance, which is plesiomorphic within “tribotherians,” makes one most archaic Marsupialiformes. Moreover, characterized by an original precocious crushing specialization. Both autapomorphic characteristics among Marsupialiformes might be explained Eastern origin Asian metatherians, some in situ European evolution. In addition, presence mammal affinities western Europe during early Late Cretaceous provides further evidence large Euramerican biogeographical province at this age or slightly before. Concerning paleobiogeographical history first marsupialiforms Albian–Cenomanian interval, 2 possible dispersal routes metatherian ancestry can proposed: Asia via America Europe. The main significance Archingeay-Les Nouillers indicates beginning involved not only but also Europe, remains virtually unknown.