Research Spotlight: New fossils challenge old preconceptions

Bonnie JacobsFor paleobotanist Bonnie Jacobs standing atop a mountain in the highlands of northwest Ethiopia, it’s as if she can see forever – or at least as far back as 30 million years ago.

Jacobs (right), an associate professor of Earth Sciences in SMU’s Dedman College and director of the Environmental Science and Studies Programs, is part of an international team of researchers hunting scientific clues to Africa’s prehistoric ecosystems.

The researchers are among the first to combine independent lines of evidence from various fossil and geochemical sources to reconstruct the prehistoric climate, landscape and ecosystems of Ethiopia in particular, and tropical Africa in general for the time interval from 65 million years ago – when dinosaurs went extinct, to about 8 million years ago – when apes split from humans.

While it’s generally held that human life began in Africa, ironically there is little known about changes in the continent’s vegetation during the time when humans were evolving.

The multi-disciplinary team is studying fossils they’ve found near Chilga, a small region in the agricultural highlands. Their work will also help climate scientists trying to model future global warming by providing data from the tropics that up to now did not exist.

Contrary to the common notion that vegetation decomposes in the tropics too quickly to supply evidence, sediments there have preserved an abundant variety of 28 million-year-old fossils. These include fruits, seeds, leaves, woods, pollen and spores, Jacobs says.

“There are lifetimes of work to be done in Africa on plant fossils alone, and certainly a lot more to be done with vertebrates as well,” says Jacobs, who’s done research in Africa since 1980 in Kenya, Tanzania and Ethiopia. “There’s not a well established record of plant fossils, so there’s no real context. It’s all new – so whatever you find is interesting.”

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