Archaeoceti, or Zeuglodontes in older literature, is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene. Representing the earliest cetacean radiation, they include the initial amphibious stages in cetacean evolution, thus are the ancestors of both modern cetacean suborders, Mysticeti and Odontoceti. This initial diversification occurred in the shallow waters that separated India and Asia 53 to 45 mya, resulting in some 30 species adapted to a fully oceanic life. Echolocation and filter-feeding evolved during a second radiation 36 to 35 mya.
Trigonostylops is an extinct genus of South American meridiungulatan ungulate, from the Late Paleocene to Late Eocene of South America and Antarctica. It is the only member of the family Trigonostylopidae.
Crassispira is a genus of small predatory sea snails with narrow, high-spired shells, marine gastropod mollusks in the family Pseudomelatomidae.
Cynthiacetus is an extinct genus of basilosaurid early whale that lived during the Late Eocene Specimens have been found in the southeastern United States and Peru.
Ocucajea is an extinct genus of basilosaurid cetacean from Middle Eocene deposits of southern Peru. Ocucajea is known from the holotype MUSM 1442, a partial skeleton. It was collected in the Archaeocete Valley site, from the Paracas Formation of the Pisco Basin about 40.4 to 37.2 million years ago.
Supayacetus is an extinct genus of basilosaurid cetacean from Middle Eocene deposits of southern Peru.
Ampullinopsis is an extinct taxonomic genus of deep-water sea snails, marine gastropod molluscs in the clade Sorbeoconcha. These sea snails were epifaunal grazers. Sea snails of this genus lived from Paleocene epoch to Miocene epoch.
Didolodontidae is a family of "condylarth" mammals known from the Paleocene to the late Eocene of South America.
Fusiturricula yasila is an extinct species of sea snail, a marine gastropod mollusk in the family Drilliidae.
Crassispira angulosa is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.
Crassispira mausseneti is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.
Crassispira nana is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.
Crassispira lepta is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies. Fossils have been found in Eocene strata in the Paris Basin, France.
Crassispira sulcata is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies. Fossils have been found in Eocene strata in the Paris Basin, France.
Crassispira furcata is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies. Fossils have been found in Eocene strata in the Paris Basin, France.
Crassispira woodringi is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies. Fossils have been found in Eocene strata in Northern Peru; age range: 40.4 to 37.2 Ma.
Crassispira margaritula is an extinct species of sea snail, a marine gastropod mollusc in the family Pseudomelatomidae, the turrids and allies.
Crassispira berthelini is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.
Eoconus sauridens is an extinct species of sea snail, a marine gastropod mollusk, in the family Conidae.
