A remarkable amount of Ardipithecus ramidus fossil remains have been discovered in Ethiopia, which exhibit very primitive morphology. For example, Ar. ramidus has long, curved manual phalanges, thin enamel, primitive deciduous first molars and first mandibular premolars. Compared to apes however, Ar. ramidus canines appear derived in that they are relatively smaller, and more incisiform, and the third molar is more elongated and large relative to the other molars. The more inferiorly placed foramen magnum hints at possible bipedalism.

Some scientists argue that Ardipithecus may represent the last common ancestor to chimpanzees and humans, while others argue there is not enough data to support this claim.

The type specimen for Ar. ramidus, ARV-VP 6/1, was found at Middle Awash and dates to 4.4 million years ago.