TropicalFossil Caviomorph Rodents from the Southwestern Brazilian Amazonia in the Context of the South American Faunas:Systematics,Biochronology,and Paleobiogeography

RIBEIRO, A.M.; FERIGOLO, J.; NEGRI, F.R.; SOUZA-FILHO, J.P.; KERBER, L.; NASIF, N. L.

JOURNAL OF MAMMALIAN EVOLUTION

SPRINGER

Lugar: Berlin; Año: 2017 vol. 24 p. 57 - 70

1064-7554

Abstract The fossil-bearing stratigraphic sections of the Solimões Formation(southwestern Brazilian Amazonia)are exposed mainly a long the Juruá,Purus,and Acre rivers, and in road cuts.These deposits have provided fossils of the four main lineages of Caviomorpha ? Cavioidea,Erethizontoidea,Octodontoidea,and Chinchilloidea, contributing to the under standing on the evolution of tropical Neogene rodents.Herein,our knowledge about fossil rodents from this region is reviewed.New specimens arerecorded,including taxa mentioned for this region for the first time,such as basal cavioids,Dolichotinae, Caviodon (Hydrochoeridae),and Drytomomys (Dinomyidae). Unfortunately,the deposits have no absolute ages,and based on palynological data and the biochronology of several taxa(mainly mammals),the encompassed fauna has been constrained to the late Miocene. However,some rodent lineages recorded here seem to be more related to older faunas,from the middle Miocene and Paleogene. Regarding the biogeographic and paleoenvironmental affinities, most of theNeogene rodents from the Acre regions how more similarities to those from the EntreRios, Argentina, and Urumaco, Venezuela, where we environments were present during Neogene times. An increase inprospecting along southwesternAmazonian rivers looking for rodents(among other vertebrates) associated with methods to better constrain the ages of these faunal assemblage swill contribute to a better understanding of the evolution of the tropical rodents as well as the stratigraphy and age that portion of the basin.