New Fossil Sheds More Light on Early Humans

Photo by Aaron Mayes/UNLV Photo Services

Photo by Aaron Mayes/UNLV Photo Services

Las Vegas frequently makes the news, but rarely for academic or scientific achievement. However, UNLV anthropologist Brian Villmoare and his team have recently been in headlines from Anaheim to Australia following their discovery of the oldest human fossil yet: a 2.8-million-year-old jawbone, which was discovered in northeastern Ethiopia and offers new insights into how we became “us.”

Why is the jawbone you found scientifically important?

Because it’s the oldest member of our genus. We’re the genus Homo. There’s Homo erectus and Homo habilus. This [fossil is from] long before that, and it’s probably right at the stem of where Homo split off from Australopithecus.

We have a good fossil record older than 3 million years. And those animals are all very apelike: Long arms, lived in the forest, fruit eaters, mostly arboreal. And then we also have a good fossil record after 2 million years. They are much more human-like: Large brains, using stone tools, eating meat. But in between [we’ve found] very little, and nothing older than 2.5 million years. … This shows that the adaptive shift toward becoming “us” happened pretty early.

How long have you been looking for this?

We’ve been trying to find fossils in this time period for more than 10 years. There’s no other way to do it than just getting out on your feet. You can’t use remote sensors or anything, so it just takes a lot of time to cover all the territory. And we knew [what it was] as soon as we saw it. A human mouth looks nothing like any animal’s, so we knew right away what it was, and we were jumping up and down on the side of the hill.

What will you search for next?

We’ll probably look for other areas that preserve the same interval, because, to my mind, it’s the most interesting in all of human evolution. There was a whole other branch [of the species] that split off and—instead of solving the problem of a dry environment with tools and large brains—responded by essentially becoming a bipedal cow: huge chewing teeth in the back, huge jawbone, huge chewing muscles. … There’s a lot about that we don’t know. We don’t know when that split happened. It would have been equally satisfying to find one of those.