Two of the most important stages in hominid evolution were the origin of the entire hominid branch some six to seven million years ago and the first movement of hominids out of their African birthplace. This week we now get a new look at both.
On the cover of Nature, the editors splashed the first reconstruction of Sahelanthropus, the oldest known hominid. The scientists who made the reconstruction used new material they found in the Sahara, adding to the material they described in their first report in 2002. There had been some argument over whether Sahelanthropus was an early hominid that looked a lot like other apes, or an ape that had a passing resemblance to hominids. The authors argue the former. They also claim that their new reconstruction provides new evidence that Sahelanthropus may have been bipedal. MSNBC reports that other scientists would prefer to see a nice pelvis or femur before accepting that claim.
Meanwhile, via John Hawks, National Geographic has a lovely display of some of the oldest hominids fossils found outside of Africa. Found in Georgia, they were initially assigned to Homo erectus, which is known to have spread all the way to Indonesia by 1.8 million years ago. But Homo erectus was a tall hominid with a big brain and a relatively flat face. The Georgia hominids, as you can see in NG’s new reconstructions, were tiny and reminiscent of earlier hominids back in Africa. Which raises the possibility, which I’ve discussed before, that the “hobbits” recently found in Indonesia (Homo floresiensis) might have been the relicts of a pre-Homo erectusmigration of little folks out of Africa. (NG also has an article on the hobbits this month, by the discoverers.)
Unfortunately, there’s also bad new about hominids these days–the hobbit bones, which were “borrowed” last fall, are a mess.
UPDATE: Minutes later…Man, Nature is hominid crazy this week. I totally missed another paper in this issue on a new skull from the Georgia hominids. What’s most interesting about this individual was that it was old and toothless. It somehow survived for a long time after losing its teeth, which suggests it got a lot of help from its fellow hominids. Old age and extended family bonds are usually considered to have evolved later in hominid evolution, but this old gum-sucker suggests otherwise.
Originally published April 6, 2005. Copyright 2005 Carl Zimmer.