Orrorin

Orrorin is an extinct genus of primate within Homininae from the Miocene Lukeino Formation and Pliocene Mabaget Formation, both of Kenya.

The type species is O. tugenenesis, named in 2001, and a second species, O. praegens, assigned to the genus in 2022.

The first part of the holotype, a lower molar, was discovered by Martin Pickford in 1974 and described by Pickford (1975).

The team that found the rest of the holotype of O. tugenensis was led by Brigitte Senut and Martin Pickford from the French National Museum of Natural History. Starting from 17 October 2000, 20 fossils were found at four sites in the Lukeino Formation, Kenya: of these, the fossils at Cheboit and Aragai are the oldest (6.1 Ma), while those in Kapsomin and Kapcheberek are found in the upper levels of the formation (5.7 Ma).

Orrorin tugenensis was named and described by Senut et al. (2001).

The second species, O. praegens, was first described by Ward (1985) and Ward & Hill (1988), and was initially described as Homo antiquus praegens by Ferguson (1989) based on specimen KNM-TH 13150, a mandible discovered in the Pliocene Mabaget Formation of Kenya during the early 1980s. The mandible is known as the Tabarin mandible, which was previously classified within Ardipithecus ramidus (or cf. A. cf. ramidus), "Ardipithecus" praegens or "Praeanthropus" praegens.

Several referred remains of O. praegens were collected between 2005 and 2011 by the Franco-Kenyan Kenya Palaeontology Expedition and they, alongside the Tabarin mandible, were classified by Pickford et al. (2022) as being separate from Homo, so they were classified within Orrorin as O. praegens.

The name of genus Orrorin (plural Orroriek) means "original man" in Tugen, and the epithet of O. tugenensis derives from Tugen Hills in Kenya, where the first fossil was found in 2000.