Australopithecus garhi
From the Awash region of Ethiopia, a new species of early human was recovered by a University of California at Berkeley excavation in the field seasons of 1996 and 1997. The most important of the finds came on November 20, 1997, when the partial cranium BOU-VP-12/130 was found, although numerous fossils from other individuals of the same species were also recovered it the same basin. The species has been named Australopithecus garhi due to its surprising morphology ("garhi" means surprise in the local Afar language). The sediments in which the fossils were found have been dated to roughly 2.5 million years ago.
Australopithecus garhi is distinguished from other species of Australopithecus, by its unique combination of dental and facial features. The cheek teeth are absolutely larger than Australopithecus afarensis, and can be said to be "megadont". However, Australopithecus garhi lacks derived characters of the robust early human lineage, leaving it as a sister taxon to the gracile forms. The morphology of the face retains primitive characteristics of Australopithecus afarensis to the exclusion of Australopithecus africanus. It is believed that Australopithecus garhi is part of the eastern African lineage descended from A. afarensis. The cranial capacity of the partial skull has been estimated at 450 cc. (under such Australopithecine individuals Ples but slightly larger than modern chimpanzee capacities). However, aspects of the dentition are very similar to early specimens of the genus Homo. Postcranially, the A. garhi material shows human-like ratios for femur to humerus length, while retaining ape-like proportions for the length of the forearm to the upper arm (the brachial index). Thus, BOU-VP-12/130 and the associated material show a strange admixture of traits recalling earlier A. afarensis and traits pointing toward later Homo.
