afarensis

Australopithecus afarensis is an extinct hominin species that lived in eastern Africa between about 3.9 and 2.9 million years ago. It is one of the best-known early human ancestors. The name derives from the Afar region of Ethiopia, where the type specimen was found, and Lucy is its most famous fossil.

Key discoveries include Lucy (AL 288-1), found in Hadar, Ethiopia, in 1974 by Donald Johanson and colleagues, and the Dikika baby Selam, about 3.3 million years old. The Laetoli footprints in Tanzania, dated to about 3.6 million years ago, are attributed to afarensis and show bipedal walking.

Anatomically, afarensis shows a mix of ape-like and human-like traits. The brain size was small, roughly 380–450 cubic centimeters. The face was prognathic, yet the dentition reveals a relatively U-shaped dental arcade with reduced canine size. Postcranially, the limb bones indicate habitual bipedalism, while the feet and hands retain some tree-climbing capabilities. The pelvis and femur suggest upright walking, and the feet’s structure supports a bipedal gait.

Habitat likely included woodland and savanna mosaics with a varied diet of fruit, leaves, seeds, and possibly meat or insects. The species is important for showing that walking on two legs preceded notable brain enlargement in hominins and helps trace the evolution toward the Homo lineage.

Classification: Australopithecus afarensis, placed among early Australopithecines; its fossils are spread across eastern Africa, notably Ethiopia and Tanzania.