Australopithecus ramidus

Australopithecus ramidus is the most recent addition to the human evolutionary tree; see [Boyd & Silk 1997] , pp 359-361.

In 1994, fossils were found by Tim White and his associates [White et al. 1994] in the Middle Awash region of Ethiopia. They subsequently named A. ramidus, a new hominid species, though it has recently been changed to Ardipithecus ramidus.

The collection of 17 fossils includes dental, cranial and postcranial material. It is dated to around 4.4 million years ago, making it the remains of the oldest known hominid.

The features include small canines (like humans) and thin tooth enamel (an african ape characteristic).

They were found near Hadar where A. afarensis was found. Preliminary palaeogeographical reconstruction suggests that the habitat was woodland.

The mode of locomotion is not yet known.

Molecular and fossil evidence suggests the split between the great apes and humans was between 5-8 million years ago, so these remains are close in age to the divergence.

• Where on the evolutionary tree would this place A. ramidus? [Wood94]
• Is it a human, ape or the root of both?

These questions have yet to be fully answered, but it may represent a long-sought potential root species for the Hominidae.