Scholar who helped ID ancient hominin to speak here

A Texas A&M anthropologist who recently helped discover two never-before-seen skeletons of a human ancestor will speak about the findings on the University of Colorado campus Nov. 5.

Darryl de Ruiter, an associate professor of anthropology at Texas A&M University, is part of a team that recently discovered Australopithecus sediba: a new species of Homo-like Australopith from South Africa.

The team found two well-preserved skeletons of a human ancestor never before seen.

The discovery was outlined in the cover story of the April 9 edition of the prestigious journal Science. Lee Berger of the University the Witwatersrand was lead author and the project director. De Ruiter, the second author, was the lead craniodental specialist on the project.

The genus name Australopithecus translates into “southern ape,” and the species is loosely referred to as an “ape man,” because they could still move around in the trees but once on the ground could walk on two legs as humans do, de Ruiter explained. “Sediba” means “fountain” or “wellspring” in the Seotho language.

“We actually think we have found the best candidate for a direct ancestor of Homo, the genus to which humans belong,” de Ruiter said of the fossils, which are believed to be between 1.78 and 1.95 million years old.

The site of the remains—a 10-by-10-foot cave about eight feet deep—was discovered in August 2008, de Ruiter said. It was actually Berger's 9-year-old son who spotted the first bone.

“When I first saw the skeletons, I knew we had something special,” said de Ruiter, who examined the skull, jaws and teeth of what is believed to be an adult female and a juvenile male—possibly members of the same group. “Both were remarkably complete and extremely well-preserved.”

He said the skulls are human-like but smaller, and their teeth are similar to humans’.

The skeletons are shaped like those of early representatives of Homo, though they are relatively small like those of the australopithecines, the ancestors of Homo. Conversely, the teeth of the new species are small like in humans, but shaped like those of Australopiths. “What we have here is a clearly transitional form,” de Ruiter stated.

Only three other skeletons of this great antiquity in Africa approach this level of completeness, de Ruiter says: the 2.9-million-year-old “Lucy” from Ethiopia, the 2.2-million-year-old “Little Foot” from elsewhere in South Africa and the 1.6-million-year-old “Nariokotome Boy” in Kenya. However, this new site is unique in revealing multiple individual skeletons that can be directly associated with each other, de Ruiter said.

The team is continuing to search for additional skeletons at the site.

De Ruiter is a paleoanthropologist specializing in the early hominins of South Africa. He has been involved in excavations at several sites in South Africa, including Swartkrans, Kromdraai, Makapansgat, Coopers, Plovers Lake and Gondolin, as well as the Koro Toro and Kossum Bogoudi regions of Chad.

He has recovered numerous hominin fossils, including cranial, dental and post-cranial remains of Australopithecus, Paranthropus and early Homo.

De Ruiter will speak to the CU community about the recent Australopithecus sediba discovery and the ongoing research surrounding it. He will discuss the relevance of the new species and how it alters many of our interpretations of hominin evolution.

De Ruiter received his Ph.D. in 2001 from the University of Witwatersrand, South Africa, and has been a faculty member at Texas A&M since 2003.

De Ruiter’s talk, which is free and open to the public, is scheduled for Friday, Nov. 5, at 4 p.m. in Hale Science Building room 270 on the CU-Boulder campus. It is sponsored by the CU Department of Anthropology’s Graduate Student Speaker Series. For more information, contact Oliver Paine at oliver.paine@colorado.edu. Texas A&M University contributed to this report.

October 2010