In the late 1990s Ethiopian palaeoanthropologist Yohannes Haile-Selassie led a series of excavations at Alaya in the Middle Awash area of the Afar Region of Ethiopia. These uncovered an ancient woodland habitat, dated to between 5.2 and 5.8 million years ago, and yielded, among other things, a collection of loose teeth and bone fragments, which Haile-Selassie assigned to the Primate Ardipithecus, at that time believed to be an ancestor of the living Chimpanzees. At that time these Late Miocene fossils were the oldest known member of the Chimpanzee lineage, only slightly younger than the presumed split between the ancestors of Chimpanzees and Humans, between 6.5 and 5.5 million years ago. These specimens were older than and not identical to those previously assigned to the Pliocene Ardipithecus ramidus, causing Haile-Selassie to erect a new subspecies, Ardipithecus ramidus kadabba ('kadabba' implies the first ancestor in the Afar language).
Further work on both the site and the fossils it yielded refined the age of the specimens to between 5.77 and 5.54 million years old. More notably, work on both Ardipithecus kadabba and Ardipithecus ramidus by Haile Salassie, along with American palaeoanthropologist Tim White, and Japanese palaeoanthropologist Gen Suwa, led to a revision of the genus Ardipithecus. Thus, Ardipithecus kadabba was promoted to a full species, probably ancestral to Ardipithecus ramidus (making it a 'chronospecies'). Furthermore, it is no longer considered to oldest ancestor of the Chimpanzee lineage, but instead is placed on the Hominin side of the family tree (anything more closely related to Humans than to Chimpanzees is a Hominin), making it the oldest member of the Human family.
