Thomasina Johnson

An ancient skeleton known as Ardi made headlines last week for being determined as the world’s oldest known human ancestor, but fewer people may know that two Miami University scientists contributed to its discovery.

William Hart, geology chair, and Brian Currie, associate professor of geology, were part of the team of scientists who published new results on the 4.4 million-year-old Ardipithecus ramidus skeleton.

The report is an accumulation of 17 years of research in the Middle Awash study area in the Afar Rift of Ethiopia, Hart said.

“The goal of the project is to understand human origins and to quantify it,” Currie said. “The project is ongoing.”

Hart, a volcanologist, said he worked on mapping and dating volcanic ash layers to create a timeline of the surrounding environment.

“If you find a fossil and it’s hard to date, once you know the date of its surrounding ash you can create a timeline,” Hart said.

Currie is a specialist in faults, which are fractures in rocks where earthquakes often occur. Faults can also give more information of the age and characteristics of the land, Currie said.

“I mapped faults and described deposits,” Currie said.

According to the Oct. 2 special edition of Science, the female hominid skeleton Ardi has enough bones to allow scientists to estimate how it walked and what it looked like.

“Ardi targets new research with hands, feet and locomotion,” Hart said. “This is what scientists are looking for in fossil records and will focus on.”

Hart added that research has shown Ardi walked on all four hands and feet, but was not a knuckle-walker.

“This should eradicate the notion that the ancestor between chimps and humans looked like a chimp,” Hart said.

According to Hart, the Middle Awash area is a “very rich, perfect environment for discovering fossils.”

Each year, floods wash away sediments and reveal fossils, Hart said.

According to the Science special issue, ancient flooding caused the Afar Rift to accumulate sediments for millions of years.

Hart said the success of the project is due to its multidisciplinary problem solving approach.

“There are hundreds of people and about two dozen regulars involved in the process,” Hart said. “It’s a great example of how science has to work to pick specialists and address issues.”

Another success of the project is the careful documentation and the cooperation with the Ethiopian people, Hart said.

“In the past, there has been a colonial approach of bringing outsiders in and not involving the natives,” Hart said. “The Middle Awash Project involves the local Afar communities and Ethiopian scientists.”

Hart got involved in the Middle Awash Project in the 1990s and Currie began in 2001. Both geologists have devoted three to six weeks for research every several years.

“We work in the fall months to avoid rainy season and the malaria season,” Currie said. “I taught a sprint course in the fall one year in order to work it out.”

According to Hart and Currie, the biggest challenge is not fitting research into a busy teaching schedule, but the logistics of getting to the Middle Awash and making a successful camp and research area.

“Forty people need provisions in the middle of the desert,” Hart said. “It takes two solid days of 20 people helping to get everything loaded and an entire day to drive out and get the camp set up. A water source has to be found.”

The temperature in the Middle Awash is at least 100 degrees and predators commonly approach the camp.

“You can see the hyenas’ eyes at night if you go out to use the bathroom in the middle of the night,” Currie said. “If you aren’t limping and you look like you know what you’re doing, they won’t attack.”

A lion walked the perimeter of the camp one year and Hart said someone found paw prints right outside a researcher’s tent.

Even though the scientists must deal with whatever nature throws at them, Hart said he is impressed by how smoothly the project runs.

“Camp is run very efficiently, and you don’t feel much danger,” Hart said.