An overview and update of South American and Antarctic fossil rheidae and putative ratitae (Aves, Palaeognathae)

Abstract

A comprehensive overview of all the South American and Antarctic fossil records of Rheiformes and close relatives, accompanied by updated stratigraphic data, is provided here. Fossil rheas are represented by fragmentary remains of hindlimb bones and several footprints that include paleospecies, extinct representatives of the living species as well as putative ratites. To date, the oldest record corresponds to the early Eocene of Argentina, Brazil and maybe Antarctica, thus the Palaeocene antiquity of several fossil sites with rheas is no longer valid. Neogene sediments present records of the exclusively fossil taxon Opisthodactylus as well as ‘Pterocnemia’. Most of the Quaternary records come from late Pleistocene-Holocene sediments from Argentina, Chile, Uruguay, Bolivia, and Brazil and are represented by extinct representatives of living species. Finally, Argentina is the country with the highest number of fossil records and taxa.