It has been a while since I blogged anything on paleoanthropology. But once I saw John Hawks‘ post where he pointed out Elizabeth Culotta’s news piece in the latest Science on a new hominin femur from Galili, Ethiopia, I was excited. The femur was presented by Bence Viola to the Society of Vertebrate Paleontology, which meet for their annual get together about two weeks ago.
Very recent argon-argon dating was done on, and Viola shared those to the Society. The bone is somewhere between between 4.38 million and 3.92 million years old. The bone indicates the individual was larger than lucy but isn’t complete. From what Culotta says, it seems as the distal end is broken off.
The anatomy of the head and neck of the femur suggest the owner was bipedal. But, the distribution of cortical bone around the femur is even. Arboreal primates have an even distirbution of cortical bone around the neck of the femora. The force of gravity and the weight of a bipedal individual causes a lot of stress on the lower half of the femoral neck. It has been observed that the cortical bone of femoral necks of bipedal hominids is thicker on the lower half, as a response to this stress. If you know anything about the debate between the Orrorin camp and the Ardipithecus camp, this should be all too familiar of a discussion.
I first read about hominid remains from Galili in this 2004 piece, which reported on the discovery of an almost complete lower right third molar (GLL 33) likely that of a male Australopithecus afarensis. Hawks pointed out a recent paper which describes the paleoecology of Galili — a open woodland to bushland ecosystem at a time when A. afarensis began replacing A. anamensis. So it is certainly possible that a semi-arboreal/bipedal hominids were navigating this terrain… But, Yohannes Haile-Selassie, who is also working on a 4 million years old hominid from Ethiopia, isn’t too convinced.
What do you think?
- E. Culotta (2008). SOCIETY OF VERTEBRATE PALEONTOLOGY 68TH ANNUAL MEETING: Two Legs Good Science, 322 (5902), 670-671 DOI: 10.1126/science.322.5902.670b