A New Pleistocene bird assemblage from the Southern Pampas (Buenos Aires, Argentina)

CENIZO, MARCOS; AGNOLIN, FEDERICO; POMI, LUCAS

PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014

0031-0182

In the present paper we report the most complete fossil avifauna from the southern cone of South America. Thespecimens here described were collected in the Paso Otero locality, at the middle streamof the Quequén GrandeRiver, Pampean Region (Buenos Aires Province, Argentina). The fossiliferous levels belong to the La ChumbiadaMember of Luján Formation (37,800 ± 2300 yr BP, late Pleistocene). The assemblage is represented by 60 specimensbelonging to at least 22 taxa. The radiocarbon age indicates that Paso Otero birds represent the oldest latePleistocene avifauna known from the South American continent and the first coming from a clear interstadialevent (MIS3). Available evidence indicates similar environmental conditions during the MIS3 interstadial inthe Pampean Region of Argentina and the post-Last Glacial Maximumstadials in southeastern Brazil. The absenceof significant extinction events in the latest Pleistocene?early Holocene avifaunas of Brazil and Argentinasuggests that the main avifaunal composition along southeastern continental lowlands may not be affected bythe cyclic retraction and extension of open environments. On the contrary, the fossil record of Peru andEcuador demonstrates that a large number of taxa, including aquatic and predatory-scavenger birds, have goneextinct along Andean environments at the Pacific coast, and late Pleistocene climatic oscillationsmay have playeda more dramatic impact in these avian communities.