Riochican

Trigonostylops is an extinct genus of South American meridiungulatan ungulate, from the Late Paleocene to Late Eocene (Itaboraian to Tinguirirican in the SALMA classification) of South America (Argentina and Peru) and Antarctica (Seymour Island). It is the only member of the family Trigonostylopidae.

Carodnia is an extinct genus of South American ungulate known from the Early Eocene of Brazil, Argentina, and Peru. Carodnia is placed in the order Xenungulata together with Etayoa and Notoetayoa.

Diogenornis is an extinct genus of ratites, that lived from the Middle Paleocene to the Early Eocene (Riochican to Casamayoran in the SALMA classification). It was described in 1983 by Brazilian scientist Herculano Marcos Ferraz de Alvarenga based on fossils found in the Itaboraí Formation in southeastern Brazil. The type species is D. fragilis. It grew to about two thirds the size of the modern greater rhea, at about of height.

Archaeopithecidae is an extinct family comprising two genera of notoungulate mammals, Teratopithecus and Archaeopithecus, both known from the Eocene of Argentina.

Bretesuchus is an extinct genus of sebecosuchian mesoeucrocodylian within the family Sebecidae known from northwestern Argentina. It was a large apex predator (total length approximately 4 m).

Lorosuchus is an extinct genus of sebecid mesoeucrocodylian known from the Río Loro Formation in Tucumán Province of northwestern Argentina.

Henricosbornia is an extinct genus of henricosborniid notoungulate that lived from the Late Paleocene to the Middle Eocene of what is now Argentina and Brazil.

Sudamerica, literally "South America" in Spanish, is a genus of mammal from the extinct suborder Gondwanatheria that lived in Patagonia, Argentina (Salamanca Formation) and Antarctica (La Meseta Formation) from the Middle Paleocene (Peligran), just after the end of the "Age of Dinosaurs", to the Early Eocene (Casamayoran).

Palmoxylon, also called petrified palmwood, is an extinct genus of palm named from petrified wood found around the world.