The fossil record of Penguins in South America

The penguins (Aves: Sphenisciformes) are the most derived group of diving seabirds. Exclusive to the Southern Hemisphere, ten of the seventeen extant species can be found in South America. South America has been recognised as one of the richest areas with fossil penguins worldwide, but until the late twentieth century this record was limited to the Argentinian Patagonia. Only at the beginning of this century were the first species from southern Peru and northern Chile described. Currently, seventeen palaeospecies have been described for South America, with a chronostratigraphic range from Middle Eocene to Late Pliocene. Traditionally the study of fossil penguins has been made on the basis of isolated specimens, with the humerus and tarsometatarsus being the most widely used elements for the typification of species. However, recently the number of skulls and partial skeletons discovered in South America has significantly increased, facilitating their interpretation and use in phylogenetic analyses. This work summarizes the fossil record of Sphenisciformes on the continent, based on type specimen revisions and the compilation of bibliographic data.