Newly Unearthed Fossils in Libya Reveal Clues to Human and Mammal Evolution

Recently discovered fossils in Libya may tell us a bit more about our own evolution. Researchers have unearthed mammal fossils in the Zallah Oasis in the Sirt Basin of central Libya that date back to the early Oligocene, which was between 30 and 31 million years ago.

The Zallah Oasis has sporadically produced fossil vertebrates since the 1960s. In this case, the researchers found a highly diverse and unique group of fossil mammals dating to the Oligocene, the final epoch of the Paleogene period. This time was marked by a broad diversity of animals that eventually led to species critical to human evolution.

"The fact that we are finding different species in Libya suggests that ancient environments in northern Africa were becoming very patchy at this time, probably because of global cooling and drying which began a short time earlier," said Christopher Beard, one of the researchers, in a news release. "That environmental patchiness seems to have promoted what we call 'allopatric speciation.' That is, when populations of the same species become isolated because of habitat fragmentation or some other barrier to free gene flow, given enough time, different species will emerge. We are still exploring how this new evolutionary dynamic may have impacted the evolution of primates and other mammals in Africa at this time."

The new fossils also include a new species of primate, called Apidium. These are the first anthropoid primate fossils known from the Oligocene of Libya. They're also the only anthropoid fossils of this age known from Africa outside of Egypt.

"Earlier hypotheses suggested that anthropoids as a group may have evolved in response to the global cooling and drying that occurred at the Eocene-Oligocene boundary," said Beard. "Our new research indicates this was certainly not the case, because anthropoids had already been around for several million years in Africa prior to that boundary. But the climate change still had a deep impact on anthropoid evolution, because habitat fragmentation and an increased level of allopatric speciation took place as a result. Anthropoids, being forest dwellers, would have been particularly impacted by forest fragmentation during the Oligocene."

The findings reveal a bit more about this time period and help fill in some gaps for mammal evolution.

The findings are published in the Journal of African Earth Sciences.

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