A team of scientists, led by Christopher Beard, professor of Ecology and Evolutionary Biology at the University of Kansas, shed light on an otherwise poorly documented interval of evolutionary history through fossils discovered in the Libyan desert.
Beard’s work focuses on the origin and evolution of primates and anthropoids — the precursors to humans. His paper unveils a discovery of mammal fossils uncovered in the Zallah Oasis in the Sirt Basin of central Libya. The fossils date back to between 30 and 31 million years ago.
The paper is available online but has yet to be published in the April edition of the Journal of African Earth Sciences, and documents the findings of a 2013 expedition.
According to the University of Kansas’ official press release of said research, the study demonstrates how climate and environmental change can alter a local ecosystem.
The team’s worked in a rock unit called the Zallah Oasis in Libya’s Sirt Basin — an area that has “sporadically” produced fossil vertebrates since the 1960s. According to the paper, the team discovered a highly diverse and unique group of fossil mammals dating to the Oligocene, a time marked by a broad diversity of animals and development of species critical to human evolution.
Beard has also discovered several new species of fauna, including a new species of the primate Apidium, which the team considers to be the most exciting of the fossils uncovered so far.
Additionally, Beard says that the fossil species his team discovered in Libya were surprisingly different from previous fossils tied to the same geologic epoch discovered in Egypt.
“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,” he’s quoted in the university’s press release as saying. “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 Zallah Incision local fauna from Libya appears to be close in age to Fayum quarries in the Jebel Qatrani Formation of Egypt and the Taqah locality in the Ashawq Formation of Oman.
“These are the first anthropoid primate fossils known from the Oligocene of Libya and the only anthropoid fossils of this age known from Africa outside of Egypt,” says the researcher. “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. 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,” he adds.
On Beard’s research team is Libyan professor Mustafa J. Salem, of the Geology department at Tripoli University – an expert on the Sahara Desert, and the one who gave Beard et al the greenlight to return to the country in 2013 “despite State Department warnings against travel to Libya,” says Beard.
The lead author of the research, however, says that another return to the field in Libya to continue the work is practically problematic, and currently impossible until the country is stable and the security of researchers can be assured.