The Barrancalobian is the first subage of the Marplatan, and is characterized by the Platygonus scagliai biozone. A possible cosmic impact occurred at the start of the Marplatan (3.3Ma) in Argentina.
Vorohuen
The Vorohuen subage contains the Akodon (Akodon) lorenzinii biozone. The first canids (Dusicyon) and mustelids (Galictis) of South America appear in Vorohuen-age sediments of the Pampas.
Sanandresian
The Sanandresian subage concludes the Marplatan, and coincides with the Ctenomys chapalmalensis ('Paractenomys chapadmalensis') biozone. A broadly cold and arid climate began in the Sanandresian, which persisted into the Ensenadan age.
123Cione, Alberto Luis (2015). The Great American Biotic Interchange: A South American Perspective. SpringerBriefs in Earth System Sciences Ser. Germán Mariano Gasparini, Esteban Soibelzon, Leopoldo Héctor Soibelzon, Eduardo Pedro Tonni. Dordrecht: Springer Netherlands. ISBN978-94-017-9791-7.