Phylogenetic evidence suggests that platyrrhine (or New World) monkeys and caviomorph rodents of the Western Hemisphere derive from source groups from the Eocene of Afro-Arabia, a landmass that was ~1500 to 2000 kilometers east of South America during the late Paleogene. Here, we report evidence for a third mammalian lineage of African origin in the Paleogene of South America—a newly discovered genus and species of parapithecid anthropoid primate from Santa Rosa in Amazonian Perú. Bayesian...

The Magellanic penguin (Spheniscus magellanicus) is a top predator and a major consumer of marine resources in the Patagonian Continental Shelf and worldwide. It is the most highly migratory of the Spheniscus penguins, but until recently, its migration route was only partially known. Regarding Magellanic penguins breeding on Isla Quiroga, in Argentina, our goals were: (1) to compare distribution during winter period between sexes and (2) if habitat is found to be segregated, to evaluate...

Molecular phylogenetics has entered a new era in which species trees are estimated from a collection of gene trees using methods that accommodate their heterogeneity and discordance with the species tree. Empirical evaluation of species trees is necessary to assess the performance (i.e., accuracy and precision) of these methods with real data, which consist of gene genealogies likely shaped by different historical and demographic processes. We analyzed 20 loci for 16 species of the South...

The late Oligocene mammalian fauna of Quebrada Fiera is one of the most diverse of the Deseadan SALMA. We describe its endemic xenarthran assemblage, represented by 13 species, including two stem sloths and 11 armored cingulates. The rare folivoran remains complete the knowledge of Octodontotherium, one of the early known mylodontids, and suggest the existence of a new small non-megalonychid megatherioid Similhapalops nivis gen. et sp. nov. The lumbar vertebrae of Octodontotherium sp. provide the...