In late November 2011 I went to Johannesburg, South Africa, to meet the newest member of the human family, a nearly two million–year-old creature dubbed Australopithecus sediba. First announced in 2010, its fossilized bones have caused quite a commotion in paleoanthropological circles—and with good reason. They are some of the most complete early hominins (the group that includes modern humans and their extinct relatives) ever found, and they exhibit a combination of apelike and humanlike traits that no one would have predicted. Think ape arm with human hand, ape heelbone adjoining human anklebone. In the cover story of the April issue, I describe the unexpected discovery of the fossils and explore the latest thinking on where Australopithecus sediba fits in our family tree. Paleoanthropologist Lee Berger of the University of the Witwatersrand, who found the fossils, thinks A. sediba could be the ancestor of our genus, Homo; other scientists disagree. Here's a short video of Berger talking about one of the two most complete skeletons from the site. The story continues below it.

» View a slide show of my snapshots of Australopithecus sediba and the Malapa site

The phylogenetic position of Australopithecus sediba is important, because scientists have been sorely lacking for evidence of how Homo got its start. But the new find is enormously important no matter how it is related to us, because it has the potential to tell scientists more than they have ever been able to glean previously about a hominin from this time period. Not only are the hominins exceptionally complete and abundant, but the site seems to have preserved some very unusual things, including, probably, skin and perhaps other organic material as well. 

Berger is bringing all the resources he can muster to bear on the project. Thus far the team is more than 80 persons strong and counting. Some are specialists in particular areas of hominin anatomy, some are studying the nonhuman animals from the site, some are analyzing plant remains, some are working on the potential organics. Geologists, geochemists and imaging experts are also involved. Berger is building a structure at the site to protect it and serve as a laboratory when formal excavation of the site gets under way later this year, at which point he expects to finds loads more fossils.

 I spent a week in Johannesburg, talking with Berger, and a number of the other members of the team. And I was able to, on two occasions, visit the site where A. sediba was found, called Malapa, 40 kilometers northwest of Johannesburg in the greater Cradle of Humankind area that fossil hunters have trawled for decades. Here are some videos of Berger showing the limestone miners’ pit where the skeletons were found, as well as areas of the site where he can see hominin bone peeking out of the ground—remains that the team will collect during excavation.

It was so incredibly exciting to see the hominin fossils still in the ground waiting to be unearthed—and to consider what else might be hiding in the fossil-rich sediments at Malapa. So stay tuned. This is the it site of the moment, and by all appearances there is so much more to come.

» View a slide show of my snapshots of Australopithecus sediba and the Malapa site