Primitive Eurasian Ancestors Turn Up in Dmanisi, Georgia

Herman Pontzer, Ph. D., who is assistant professor of physical anthropology at Washington University in St. Louis, along with a team of international researchers, has made the determination that the first human ancestors to inhabit Eurasia were more primitive than previously believed.

This determination came through the team's analysis of the earliest known hominid fossils in existence outside of Africa. These were recently discovered in Dmanisi, Georgia, of the former Soviet republic. Currently a semi-presidential republic having both an active president and prime minister, Georgia is situated in the Caucasus Mountains on the east coast of the Black Sea and is bounded on the north by Russia and on the south by Turkey and Armenia. Its eastern border adjoins Azerbaijan.

The fossils, which are dated as being 1.8 million years old, show some aspects of lower limb morphology that matche what we consider modern skeletal morphology. Such aspects include long legs and an arched foot. The fossils, however, do retain some primitive aspects of morphology in the shoulder and foot. The stature and brain size of the species are small and therefore more similar to earlier species that are found in Africa.

The researchers therefore conclude, "Thus, the earliest known hominins to have lived outside Africa in temperate zones of Eurasia did not yet display the full set of derived skeletal features."

This new evidence and analysis of the first human ancestors to migrate to Eurasia from Africa shows that this species had the anatomical and behavioral capacity to be successful across a range of environments. Pontzer, who studies how the musculoskeletal anatomy of an animal reflect its performance, ecological niche and evolutionary history, has said that the morphology of the fossilized skeleton indicates how it could successfully expand out of Africa.

As Pontzer states, "This research tells us that the limb proportions and behavioral flexibility which allowed this species to expand out of Africa were there at least 1.8 million years ago." Although, some primitive morphology was retained which makes these Eurasian hominids more primitive than previously thought.
Dmanisi is the site of a medieval village located about 53 miles southwest of Tbilisi, Georgia on a promontory at the confluence of the Mashavera and Phinezauri rivers. Archaeological exploration of the ruins began in the 1930s, but systematic excavations were not undertaken until the 1980s. Pontzer has been studying the site for more than six years.

Additionally, the history of Dmanisi is a long and varied one going back to the Early Bronze Age. In 1984 discovery of primitive stone tools led to the renewal of interest in Dmanisi as a archaeologically rich site and soon Georgian researchers were joined by international scholars. Hominid fossils, named Homo georgicus, were discovered between 1995 and 2001.

The lead author of the paper dealing with the primitive morphology of the Dmanisi fossils is David Lordpkipanidze, who is director of the National Museum of Georgia. Collaborators on the study include Pontzer and researchers from Georgia, Switzerland, Italy and Spain. The findings, published Sept. 20 in the journal "Nature," are a significant step in learning more about the first human ancestors to migrate to Eurasia from Africa.

Source:
Neil Schoenherr, "Human ancestors more primitive than once thought," University of Washington in St. Louis.