New Paleogene marsupials from the Amazonian basin, Southeastern Perú

GOIN, F.J. Y A. M. CANDELA

The Paleogene Mammalian Fauna of Santa Rosa, Amazonian Perú

Natural History Museum of Los Angeles County

Lugar: Los Angeles; Año: 2004; p. 15 - 60

An analysis of 79 fossil specimens, most comprising tiny, isolated upper and lower molars recovered from Paleogene levels near Santa Rosa, in the Peruvian Amazon, led to the recognition of eight new genera and eleven new species of extinct marsupials.  Rumiodon inti gen. et sp. nov. (Didelphimorphia, ?Herpetotheriidae), Patene campbelli sp. nov. (Sparassodonta, Hathliacynidae), Incadolops ucayali gen. et sp. nov. (Polydolopimorphia, Prepidolopidae), Wamradolops tsullodon gen. et sp. nov. (Polydolopimorphia, family indet.), Hondonadia pittmanae sp. nov. (Polydolopimorphia, family indet.),  Perulestes cardichi and P. fraileyi gen. et spp. nov. (Paucituberculata, Caenolestidae), Sasawatsu mahaynaq gen. et sp. nov. (Paucituberculata, ?Palaeothentidae), Kirutherium paititiensis gen. et sp. nov. (Microbiotheria, Microbiotheriidae), Wirunodon chanku gen. et sp. nov. (order and family indet.), and Kiruwamaq chisu gen. et sp. nov. (order and family indet.).  The marsupial that best resembles Wirunodon chanku is Kasserinotherium tunisiense, from the lower Eocene of Africa.  Perulestes and Sasawatsu represent early stages in the evolution of the paucituberculatan quadrangular upper molar; their combined features confirm that paucituberculatans and polydolopimorphians do not belong to a natural group.  Wamradolops, Incadolops, and Hondonadia add significant information on the evolution of several major polydolopimorphian lineages.  A formal suprageneric taxonomy for the Order Polydolopimorphia, included in a major (unnamed) taxon together with microbiotherians (and diprotodontians?) is proposed.  Frugivorous or frugivorous-insectivorous adaptive types are dominant among the Santa Rosa marsupials, with Wamradolops tsullodon the most abundant, comprising almost half of all marsupial specimens.  A comparative analysis of the Santa Rosa marsupials with those of other Paleogene South American faunas failed to correlate it with any known South American Land Mammal Age.  We conclude that the age of this fauna is, most probably, middle to late Eocene, although the possibility of an early Oligocene age should not yet be discarded.