Caley Orr, an assistant professor in the Department of Anatomy at Midwestern University, and Eric Delson, a paleoanthropologist at Lehman College/CUNY and the American Museum of Natural History, both think that the new theory erasing the other Homo species is intriguing, but believe that more specimens and additional research are needed to fully validate it.
Darren Curnoe, an associate professor in the School of Biological, Earth & Environmental Sciences at the University of New South Wales; Chris Stringer of the Natural History Museum, London; and Ian Tattersall of the American Museum of Natural History support the broader significance of the Dmanisi fossils, but doubt that all of the early Homo fossils can reasonably be lumped into an evolving Homo erectus lineage.
Tattersall said, "Paleoanthropologists are having a hard time letting go of the old idea that human evolution was a linear process, but fossils like this one from Dmanisi are making it ever clearer that hominid history has been one of diversity and evolutionary experimentation with the hominid potential."
Clive Gamble, professor of archaeology at the University of Southampton, pointed out another intriguing possibility -- that the early human homeland wasn't just in Africa or Asia, but instead encompassed both regions and possibly more.
"Rather than seeing the Dmanisi skulls as the first excursion of the earliest Homo outside Africa, what they suggest is that the homeland of small-brained Homo was always bigger than Africa," Gamble told Discovery News.
"…The time has come for paleoanthropologists to broaden their idea of what evolutionary landscapes looked like almost 2 million years ago. To call them Africa or Asia and draw arrows between them misses the significance of Dmanisi for understanding our earliest evolution."