Do we need to rethink the names of early Homo species? A 1.8-million-year-old skull that turned up in Georgia is prompting a closer look.
The skull was excavated several years ago, and was the fifth well-preserved hominid skull to be discovered at the site in Dmanisi. It has a remarkably large face and small cranium. The five skulls, thought to be from Homo erectus, come from the same place, and their owners likely lived at a roughly similar time, so researchers compared the fossils in the haul.
"Firstly, the Dmanisi individuals all belong to a population of a single early Homo species," says Prof Christoph Zollikofer from the University of Zurich,
co-author of a study just published in Science. "Secondly, the five Dmanisi individuals are conspicuously different from each other, but not more different than any five modern human individuals, or five chimpanzee individuals from a given population."
And when they compared the Dmanisi fossils with hominid fossils from Africa, it raised questions about whether some hominid species were really different species at all.
"It remains to be tested whether all of the fossils currently allocated to the taxa H habilis and H rudolfensis belong to a single evolving Homo lineage," they write.
The findings don't change the general understanding that hominids spread out of Africa and into Europe and Asia, but they suggest we currently classify into too many groups, according to archaeologist Dr Ron Pinhasi of University College Dublin.
He was not involved in this study but he also carries out work in Georgia. "If any of these five Dmanisi skulls were found in a range of locations across Eurasia, they would probably be assigned to different taxa and also possibly to different Homo species," he says. "The scant fossil record, and especially the lack of finds with exceptional preservation, means that we constantly undermine the true diversity of past species."
