4.4 million years ago: earliest bipedal hominid.
Ardipithecus ramidus is the name of a hominid fossil dated 4.4 million years ago, found by Tim White and his team in the Great Rift Valley, in Ethiopia.
While working in 1992 in the village of Aramis, 250 km northeast of Addis Abeba, White and his group found a tooth of an individual who could have been an ancestor of Homo sapiens.
Excavations resumed in 1994. Working with his student Yohannes Haile-Selassie, White found bones from the hand, pelvis, leg, ankle, foot, arm, fist, jaw, teeth, and a skull. All the remains seemed to belong to a single individual since there were no duplicates.
In 1994, the fossil nicknamed Ardi became the oldest human ancestor ever found, a place Lucy had occupied for 20 years.
The poor state of the remains forced the team to move to the National Museum of Ethiopia, and work at the laboratories. It took them more than three years to complete the job. Although everyone knew about the existence of this fossil since the 90s, it was not until 2009 that the discovery of Ardipithecus ramidus was formally published. Ardi was a female individual with a cranial capacity of one pound.
From the shape of the bones, the team concluded Ardi did not knuckle-walk. Its spine has a more vertical position than today’s apes. We do not know whether it is a hominid ancestor or a close relative of the human and chimps common ancestor. What we do know is that it was bipedal while on the ground and quadrupedal when climbing trees.