Known from the middle Awash study area, Afar rift, Ethiopia. The fossils were found between 1977 and 2003, and are mostly 5.6 to 5.7 million years old. Together with the Kenyan and Chadian fossils (Orrorin and Sahelanthropus), Ar. Kadabba, represents the earliest ancestor of humans yet known, at around 6 million years ago.

Ar. Kaddabba generally resembles the later Ar. Ramidus, but the canines are slightly more primitive. The species name comes from the Afar word “Kadabba” which means “big father” or “basal family member”. As with Ar. Ramidus, the species is found together with animals that suggest that the earliest human ancestors mostly lived in a wooded environment. The lower jaw is chimpanzee sized but some what more robust, foreshadowing the later Australopithecus condition. Its diet was perhaps not so dependent on ripe fruit as in the modern chimpanzee. The canine of this specimen is blunted from the tip, as it is the case in Australopethicus and humans. This shows that, in contrast to apes and monkeys, the canines that are pointed in shape, similar to female ape canines. The post crania (body parts) include partially preserved humeri (upper arm bone) and ulna (forearm bone), a clavicle (collar bone), and a foot phalanx (toe bone).

Source: Authority for Research and Conservation of Cultural Heritage