Revolutionary discovery resolves uncertainties about early human evolution.

[Elphaba]

Ardipithecus ramidus and the Paleobiology of Early Hominids -- White et al. 326 (5949): 64 Data Supplement - Author Summary -- Science

The results, and conclusions, of fifteen years of research have been documented by a large international team with diverse areas of expertise, and these papers are rocking the world of paleontology because a major discover has profoundly changed our understanding of human evolution, including our belief about our commmon ancestor. According to the summary:

The 11 papers in this issue . . . describe Ardipithecus ramidus [nicknamed "Ardi"], a hominid species dated to 4.4 Ma, and the habitat in which it lived in the Afar Rift region of northeastern Ethiopia.

This species, substantially more primitive than Australopithecus, [lived after Ardi 1 to 4 million years ago] resolves many uncertainties about early human evolution, including the nature of the last common ancestor that we shared with the line leading to living chimpanzees and bonobos.

Ar. ramidus, first described in 1994 from teeth and jaw fragments, is now represented by 110 specimens, including a partial female skeleton rescued from erosional degradation. This individual weighed about 50 kg and stood about 120 cm tall. In the context of the many other recovered individuals of this species, this suggests little body size difference between males and females. Brain size was as small as in living chimpanzees. The numerous recovered teeth and a largely complete skull show that Ar. ramidus had a small face and a reduced canine/premolar complex, indicative of minimal social aggression.

Its hands, arms, feet, pelvis, and legs collectively reveal that it moved capably in the trees, supported on its feet and palms (palmigrade clambering), but lacked any characteristics typical of the suspension, vertical climbing, or knuckle-walking of modern gorillas and chimps. Terrestrially, it engaged in a form of bipedality more primitive than that of Australopithecus, and it lacked adaptation to “heavy” chewing related to open environments (seen in later Australopithecus).

Ar. ramidus thus indicates that the last common ancestors of humans and African apes were not chimpanzee-like and that both hominids and extant African apes are each highly specialized, but through very different evolutionary pathways. (bold and paragraph breaks mine)

This last paragraph describes why the discovery of Ardi is so revolutionary. In fact, textbooks that currently describe our common ancestor as being chimpanzee-like are now obsolete. They will have to be revised and republished.

As I said above, this discovery has rocked the paloentology world, and their blogs are boiling over about it. I can barely keep up with ninety percent of what they write, but the ten percent I can understand is fascinating.

[Godless]

This is an amazing discovery. Thanks for sharing it!

[Maxel]

Exciting! I didn't hear about this until now.