ARDI

Ardi is the nickname commonly used for the fossil specimen of Ardipithecus ramidus, an early hominin species discovered in the Afar Region of Ethiopia. The remains, including a substantial portion of a female skeleton, were found during fieldwork conducted in 1994–1995 by a team led by Berhane Asfaw and Tim White. Radiometric dating places Ardi at roughly 4.4 million years old, making it one of the oldest and most complete early hominin skeletons recovered.

The Ardi specimen provides important evidence about early human evolution. Its anatomy shows a mosaic of traits: adaptations for bipedal locomotion on the ground paired with features suited to arboreal climbing, such as a grasping foot with a divergent big toe. This combination suggests that upright walking emerged in the context of a mixed locomotor lifestyle rather than via a simple, linear shift from tree-dwelling to terrestrial walking.

The discovery has influenced views of how and when bipedalism evolved, indicating that upright walking appeared earlier and in different ecological circumstances than previously thought. The full description of Ardi and its species was published in 2009 in the journal Science by White and colleagues.

Beyond paleontology, Ardi is also used as a given name or nickname in various cultures, and as an acronym or designation in unrelated fields, though these uses are distinct from the fossil.