Ar. ramidus is considered by some to be the oldest-known hominid. Ar. ramidus shares some novel characteristics with later hominids, including being bipedal and its teeth. As the molars of Ar. ramidus are smaller than those of any of the Australopithecus species. Further evidence, indicates that it may have been a woodland forest dweller.

(Note: This species has not yet been fully described because some of the specimens have been difficult to extract from the surrounding rock.)