The document discusses the genus Australopithecus, which was an early hominin that evolved in Eastern Africa around 4 million years ago. Several Australopithecus species emerged during this time period, including A. afarensis, A. africanus, A. anamensis, and A. garhi. A. anamensis is considered the earliest known Australopithecus, existing between 3.8-4.2 million years ago. Evidence from fossils shows that A. anamensis could walk on two legs but also had adaptations for climbing trees.