Ardipithecus kadabba

Ardipithecus kadabba is an extinct early hominin species known from fossils found in Ethiopia and dated to about 5.8–5.2 million years ago.

Afar Rift: A tectonic depression in northeastern Ethiopia and neighboring countries, marked by active rifting and extensive fossil deposits. The species’ fossils came from the Afar region, where tectonic activity exposed ancient deposits.
Hominini: The tribe of apes that includes humans and their extinct relatives after the human lineage separated from the chimpanzee lineage. Kadabba is classified within the human-side lineage rather than among other apes.
Bipedal gait: A walking pattern in which the body is supported and propelled by alternating steps on two legs. The toe bone’s shape has been interpreted as evidence of a bipedal gait.
Chimpanzee: A great ape native to tropical Africa and the closest living relative of humans. Living chimpanzees provide a comparison, though they are not unchanged models of ancestral hominins.
Middle Awash: A fossil-rich research area in Ethiopia’s Afar region, spanning deposits from the late Miocene onward. Fieldwork there recovered the fossils assigned to Ardipithecus kadabba.
Hominin: A member of the human evolutionary lineage after its separation from the lineage leading to chimpanzees. This classification is the central evolutionary claim attached to kadabba.
Hominin fossil record: The preserved fossil evidence used to reconstruct the evolution of humans and their extinct relatives. Kadabba’s sparse remains contribute to a record with major gaps near its age.
Gorilla: A genus of large African great apes comprising two species and their subspecies. Gorilla anatomy offers another living-ape comparison for interpreting early hominin traits.
Aramis, Ethiopia: A fossil site in Ethiopia’s Middle Awash region, known especially for remains of Ardipithecus ramidus. Its younger hominin fossils help place kadabba within the regional record.
Bipedalism: Locomotion using two legs as the primary means of movement. Foot and leg evidence bears on whether kadabba moved habitually on two legs.

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ArdipithecusBroader topic: Its older fossils extend the genus’s record before Ardi.