USF geologists discover oldest known fossilized markings

When a team of globally renowned scientists unearthed bones in winter 2009, they weren’t expecting them to rewrite history and land them in numerous magazine articles, such as one in Nature earlier this month.

Geology professor Jonathan Wynn and his graduate student, Zelalem Bedaso, are part of the Dikika Research Project team who discovered fossilized bones possibly marked by stone tools. The bones are thought to date further back than when history books orignally depicted the earliest form of human life first emerging.

The team was led by Ethiopian paleoanthropologist Zeresenay Alemseged, who discovered “Lucy’s Child” – the oldest living species to date – in late 2000.

The team, which is taking a two-year break to research its findings, were searching for fossils around the Ethiopian digging sites of Gona and Bouri when the discovery was made, Wynn said.

On the day of the discovery, archaeologist Shannon McPherron, another member of the team, noticed a couple of the bones had those on them – resembling cut marks made by stone tools.

The whole team was taken by surprise, Wynn said, as the only known species surviving beyond 2.5 million years ago were members of “Lucy’s” species – an early human species called hominids – or Australopithecus afarensis, which were slender-built ancestors to modern humans.

The team found that the cuts on the fossils predate what was thought to be the introduction of stone tools between 2.5 to 2.6 million years ago, before the rise of modern humans or hominids.

“The big question essentially is whether the hominids actually manufactured these stone tools, or did they just pick up a sharp piece of tool and realized that it could be used as a stone (rock)?” Wynn said.

Wynn said that the micro-ridges and the V-shaped indentation in the bone are similar to a sharp-edge tool.

“According to archaeologist Dr. Curtis Martin, the evidence presented on these bones (is) very compelling and consistent with stone tools,” said Bedaso, who is also a Ph.D. candidate at the Department of Geology.

The markings also provide the first evidence that hominids ate meat, Wynn said.

“The protein from the meat provides more energy for the hominids compared to the vegetation, which provided them (hominids) with little energy,” he said.

Protein also gives rise to greater brain development, he said, since more energy is obtained and can be used for the development of a larger cranial capacity, which in turn contributes to human evolution.

Gregory Herbert, a professor at the geology department who was not involved in the research, said the find is “incredible” and places USF in the public eye.

“It think that it is fascinating as it puts USF’s paleontologists on the map,” he said. “Lately’ many paleontologists … have been publishing articles and findings in globally renowned journals … and have been working hard to establish a good group of scientist here at the Department of Geology. It certainly changes my teaching because the last part of my lecture I teach human evolution.”

When it comes to the classroom, Wynn said his lectures and textbooks will have to be changed as well.

“I looked at my lecture notes and it states that Homo habilis are the earliest to use stone tools, about 2.5 million years ago, when now we have compelling evidence that hominids might have been the first species to use stone tools,” he said.

Wynn and Bedaso are currently reconstructing a model of the environment where the fossils lived between 5 million and 3.4 million years ago. By using the oxygen isotope, the climatic condition at that time can be reconstructed for further research.

“The discovery of these markings say more about the hominids and could essentially explain the gaps in history of human life,” Wynn said. “Though this evidence is significant, it is just the beginning of the journey of early human history.”