If you were this man, you’d be smiling too.
The man is Lee Berger, a paleoanthropologist at the University of Witwatersrand in South Africa. He’s holding the skull of Australopithecus sediba, a 1.98 million year old relative of humans, otherwise known as a hominin. In April 2010 Berger and his colleagues first unveiled the fossil in the journal Science. As I wrote in Slate, Berger argued that A. sediba was the closest known cousin to our genus Homo. Hominins branched off from other apes about 7 million years ago, but aside from becoming bipedal, they were remarkably like other apes for about five million years. Among other things, they were short, had long arms, and had small brains. Berger and his colleagues saw in A. sediba what biologists often find in transitional forms–a mix of ancestral and newer traits. It has Homo-like hands, a projecting nose, and relatively long legs. It was intermediate in heigh between earlier hominins and the tall Homo. And it still had a small brain and long arms. (In August, Josh Fishman wrote a feature for National Geographic on A. sediba, complete with excellent reconstructions.)