The present work consists of a study on the Cenozoic Ostracodes of the Upper Amazon Basin based on three wells and one outcrop.
Six new genera and nine new species are described and their significance to paleoecology and stratigraphy are discussed. Nearly all the ostracodes studied were new forms thus confirming previous studies based on molluscs suggesting the fauna to be endemic. Thanatocoenosis has taken place as shown by the presence of reworked material consisting of typically brackishwater (sic) ostracodes associated with freshwater forms as well as by the associated presence of Mesozoic and Cenozoic forms. The latter are represented by genera such as
Bisulcocypris and
Cypridea, Upper Jurassic to Lower Cretaceous forms together with Cenozoic ostracodes, among which there are some forms probably belonging to an age as late as Pliocene.
The name Pebas Formation is maintained instead of Solimões even for those beds in the Brazilian side.
