Specialist in Dmanisi Region, Wellesley Professor Talks to News Outlets about Recent Analysis of Area Fossil

October 21, 2013

Assistant Professor of Anthropology Adam Van Arsdale has spoken extensively to the press over the last few days as the news was announced that a 1.8 million-year-old complete human skull provides new evidence that humans descended from a single, slow-evolving species rather than multiple species as previously believed.

This new evidence was provided by researchers analyzing the skull for a paper published this week in Science. The skull, known as Dmanisi 5 and one of the only complete human skulls of its age, was uncovered in the fossil site in Dmanisi, Georgia. Researchers David Lordkipanidze of the Georgian National Museum and his colleagues pointed out the similarities the skull shared with other specimens found in Africa, despite the geographical distance between the two sites. This challenges previously held assumptions that there were as many as four or five Homo species.

Van Arsdale is a biological anthropologist with a specialization in paleoanthropology. His research focuses on the pattern of evolutionary change in humans over the past two million years, with an emphasis on the early evolution and dispersal of the genus Homo. His work spans a number of areas including comparative anatomy, genetics, and demography. While he was not on the Lordkipanidze publication, Van Arsdale has done extensive work in the Dmanisi site where the fossil was found; in fact, as described in his blog, he was present when the fossil was first uncovered in 2005.

WBUR’s Science Friday invited Van Arsdale to speak about the discovery. He explained the unique opportunities presented by the Dmanisi site. “The fossils are really what make the site spectacular, though. One of the really unique things about Dmanisi is that it’s a single site at a single place in time. All the hominem fossils are all coming from a very short, narrow window in time, and they’re all very complete. We have lots of preserved elements from multiple individuals, which makes it a unique comparison to look at other fossil localities in terms of the variation presented by the Dmanisi fossils.” Of Dmanisi 5, he said, “It’s probably the best preserved fossil of a human skull over 100,000 years of age.” Van Arsdale explained that the skull was not “new” in the sense of a new species but in bolstering new understanding of the possibilities of variation within a single species at one particular place and time.

As the Boston Globe reported, Van Arsdale has been arguing for some time that there were fewer species of early Homo variations than commonly believed. Van Arsdale told the Globe, “If you look around Boston today and look at the way people differ, the two biggest ways they differ is how old they are and if they’re male or female—so what we have in Dmanisi in the five relatively complete skulls is individuals who vary in age from late adolescent to older adult, and we have individuals who vary in sex… I agree that we’ve been naming too many species in East Africa, because I don’t think we’ve been appreciating the full spectrum.”

The Christian Science Monitor published an extensive article on the skull and its implications for human origins, relying on Van Arsdale for providing the contextual significance of the Dmanisi site. Van Arsdale explained to the paper that during this historic period, “With plenty of water available, the location would have attracted animals large and small, in addition to early humans. Fossilized remains include saber-tooth cats, medium-size deer, and wolves, as well as rodents and other small animals that live in arid terrain. These smaller animals help define the climate locally because they don't travel far.”

Van Arsdale’s research was also cited in The Nation, Kenya’s Daily Nation, the Irish Examiner, Taipei Times, Nepal's Republica, and other news outlets.

In addition to his on-campus classes, Van Arsdale is teaching 207x: Introduction to Human Evolution, the first WellesleyX course to be offered as part of the edX online learning collaborative. Among many other topics, the course investigates biological variation.