INTERVIEW: Fossil finds add ancestors - and a puzzle - to our human family tree

A team of researchers say they’ve found fossils that add two new ancestors to our human family tree. While these two creatures appeared to have lived at the same time - and in the same place - they are two distinct, different hominins. The team says one set of fossils appears to be a fit for the genus Homo. That’s the same genus as modern humans. The other seems to fit Australopithecus, the same genus as the famous Lucy fossil. Fossil teeth and bones from both creatures were found at Ledi-Geraru in Ethiopia. It’s a desert site about 30 miles from where the famous Lucy fossil was found. But the research team concluded that the Ledi-Geraru Australopithecus teeth are a new species, rather than belonging to Lucy’s species, Australopithecus afarensis. The new Homo teeth also don’t appear to match any known Homo species. These new fossils date between 2.6 and 2.8 million years ago, and shed new light on human evolution. They are younger than the Lucy fossil, which is dated as being about 3.2 million years old. In this edition of Weekend One on One we hear from two members of the research team, Chris Campisano and Kaye Reed from Arizona State University in the US.