[4] 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.

[9] The epithet of O. praegens means roughly “group of people who came before.”[3] The 20 specimens belonging to O. tugenensis are believed to be from at least five individuals.

Its dentition differs from that found in Australopithecus in that its cheek teeth are smaller and less elongated mesiodistally and from Ardipithecus in that its enamel is thicker.

[11] In the femur, the head is spherical and rotated anteriorly; the neck is elongated and oval in section and the lesser trochanter protrudes medially.

Since then, according to the Community Museums of Kenya chairman Eustace Kitonga, the fossils are stored at a secret bank vault in Nairobi.

The main similarity is that the Orrorin femur is morphologically closer to that of Homo sapiens than is Lucy's; there is, however, some debate over this point.

[13] This debate is largely centered around the fact that Lucy was female and the Orrorin femur it has been compared to belonged to a male.

[14] Other fossils (leaves and many mammals) found in the Lukeino Formation show that Orrorin lived in a dry evergreen forest environment, not the savanna assumed by many theories of human evolution.

[16] O. tugenensis shares an early hominin feature in which their iliac blade is flared to help counter the torque of their body weight; this shows that they adapted bipedalism around 6 MYA.

[16] It has been suggested by Pickford that the many features Orrorin shares with modern humans show that it is more closely related to Homo sapiens than to Australopithecus.