Human evolution: other partially upright ancient fossils (Introduction)

by David Turell @, Friday, November 20, 2020, 04:40 (13 days ago) @ David Turell

There are several:

"In a discovery that upends the study of human origins, scientists have unearthed remains of what they say is the earliest known member of the human evolutionary family. Investigators led by anthropologist Michel Brunet of the University of Poitiers in France estimate that the creature, officially dubbed Sahelanthropus tchadensis, lived between 7 million and 6 million years ago.


"First, a small braincase like that of living chimpanzees connects to a face and teeth resembling those of bigger-brained hominids dating to 1.75 million years ago, perhaps even early Homo specimens. No one had predicted that elements of later skulls–in particular, a short, relatively flat face, pronounced brow ridge, and small canine teeth–coexisted with a chimp-size brain in early hominids.

"Second, Brunet and his colleagues made their discovery in Chad, a central African nation located far from established fossil-hominid sites in eastern and southern Africa. It appears that, between 7 million and 5 million years ago, hominids evolved into a wider variety of lineages across a broader area than scientists had assumed, says anthropologist Bernard Wood of George Washington University in Washington, D.C.

“'This is an astonishing find,” remarks anthropologist Daniel Lieberman of Harvard University. “Hominid species in eastern and southern Africa appear to have been a small part of a more complicated evolutionary process.”

And another early transitional form:

"The fragmentary remains come from at least five individuals–in the genus Ardipithecus–who lived between 5.2 million and 5.8 million years ago, says anthropology graduate student Yohannes Haile-Selassie of the University of California, Berkeley.


"Much is also unknown about Ardipithecus‘ looks. The new finds consist of a partial jaw, a few teeth, several hand and foot bones, and pieces of an upper-arm bone and a collarbone. The bones are about the size of those from a modern common chimp. However, Ardipithecus displays dental features found in other hominids but not in any fossil or living ape.

"Moreover, the new finds include a toe bone shaped like those of Lucy and her kind. This constitutes “subtle but clear evidence” that Ardipithecus, like Australopithecus, walked on two legs, says anthropologist C. Owen Lovejoy of Kent (Ohio) State University, who independently examined the toe fossil. Ongoing studies of 4.4-million-year-old Ardipithecus fossils will further illuminate this hominid’s stance, Lovejoy says.

"The fossils were unearthed at sites in what is now a desert. When Ardipithecus lived there, the region contained a dense forest and had a cool, wet climate, according to studies led by Giday WoldeGabriel of Los Alamos (N.M.) National Laboratory." (my bold)

The new finds raise puzzling questions about why early hominids evolved an upright stance, Maclatchy adds. Researchers have often portrayed a two-legged stride as an adaptation to trekking across hot, grassy savannas. Yet Ardipithecus lived in shady forests where a hominid would have less need to stand up to dissipate heat or walk long distances.

Comment: There is no evidence (note the bold) that these guys were forced out of trees and had to change/adapt. The forests were there. I view this, as always, as change in preparation of what was to come. In other words, God in charge.

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