Science Series, Number 40, pp. 15–60 Natural History Museum of Los Angeles County, 2004 New Paleogene Marsupials from the Amazon Basin of Eastern Peru ´ Francisco J. Goin 1,2 and Adriana M. Candela 1 ABSTRACT. 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, cf. Herpetotheriidae), Pa- tene campbelli sp. nov. (Sparassodonta, Hathliacynidae), Incadolops ucayali gen. et sp. nov. (Polydolopimorphia, Prepidolopidae), Wamradolops tsullodon gen. et sp. nov. (Po- lydolopimorphia, family indeterminate), Hondonadia pittmanae sp. nov. (Polydolopi- morphia, family indeterminate), Perulestes cardichi and P. fraileyi gen. et spp. nov. (Pau- cituberculata, Caenolestidae), Sasawatsu mahaynaq gen. et sp. nov. (Paucituberculata, cf. Palaeothentidae), Kirutherium paititiensis gen. et sp. nov. (Microbiotheria, Micro- biotheriidae), Wirunodon chanku gen. et sp. nov. (order and family indeterminate), and Kiruwamaq chisu gen. et sp. nov. (order and family indeterminate). The marsupial that best resembles W. chanku is Kasserinotherium tunisiense, from the lower Eocene of Africa. Perulestes and Sasawatsu represent early stages in the evolution of the paucitu- berculatan quadrangular upper molar; their combined features confirm that paucituber- culatans 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 Po- lydolopimorphia, 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 W. tsullodon the most abun- dant, 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. RESUMEN. El ana ´lisis de 79 especı´menes fo ´ siles consistentes en su mayor parte en molares superiores e inferiores de muy pequen ˜ o taman ˜ o, procedentes de niveles paleo ´- genos cercanos a la localidad de Santa Rosa, en la Amazonia peruana, permitio ´ el re- conocimiento de once nuevas especies de marsupiales extinguidos: Rumiodon inti gen. et sp. nov. (Didelphimorphia,? Herpetotheriidae), Patene campbelli sp. nov. (Sparasso- donta, Hathliacynidae), Incadolops ucayali gen. et sp. nov. (Polydolopimorphia, Prepi- dolopidae), Wamradolops tsullodon gen. et sp. nov. (Polydolopimorphia, familia indet.), Hondonadia pittmanae sp. nov. (Polydolopimorphia, familia indet.), Perulestes cardichi y P. fraileyi gen. et spp. nov. (Paucituberculata, Caenolestidae), Sasawatsu mahaynaq gen. et sp. nov. (Paucituberculata, cf. Palaeothentidae), Kirutherium paititiensis gen. et sp. nov. (Microbiotheria, Microbiotheriidae), Wirunodon chanku gen. et sp. nov. (orden y familia indet.) y Kiruwamaq chisu gen. et sp. nov. (orden y familia indet.). El u ´ nico marsupial conocido que recuerda a W. chanku es Kasserinotherium tunisiense, del Eoceno temprano de Africa. Perulestes y Sasawatsu representan estadı´os tempranos en la evolucio ´ n del patro ´ n molar de los Paucituberculata; su combinacio ´ n de caracteres confirma que los Paucituberculata y los Polydolopimorphia no constituyen un grupo natural. Los polidolopimorfios Wamradolops, Incadolops y Hondonadia agregan infor- macio ´ n significativa sobre la evolucio ´n de varios linajes de este orden. Se propone for- malmente una nueva taxonomı´a supragene ´rica del Orden Polydolopimorphia, el cual se incluye en un grupo mayor (innominado) junto con los Microbiotheria (¿y los Dipro- todontia?). Los tipos frugı ´voros o frugı´voro–insectı ´voros son dominantes en esta fauna, siendo W. tsullodon el ma ´ s abundantemente representado, con casi la mitad de los es- 1 Departamento Paleontologı´a Vertebrados, Museo de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina.Email: fgoin@museo.fcnym.unlp.edu.ar and acandela@museo.fcnym.unlp.edu.ar 2 Correspondence