#FossilFriday feature: Drimolen skull shows evidence of microevolution

A skull discovered at the Drimolen Palaeocave System in the Cradle of Humankind World Heritage Site is making global headlines. Researchers say the Paranthropus robustus specimen shows evidence of microevolution. The researchers published their findings earlier this week.

“We discovered DNH 155 on Father’s Day 2018. It is fitting that a big male was found on a day when we celebrate fatherhood,” says Stephanie Baker from the Palaeo-Research Institute at the University of Johannesburg in a statement.

Below is a video about the project at Drimolen:

In order to understand why this finding is significant, it is important to know that, about two million years ago, this area in the Cradle of Humankind World Heritage site underwent a dramatic shift in climate – going from a lush, green area to a dry and arid place.

With this change, the type of food available to species living in the area also changed. This means that, over time, they would have had to adapt from a diet of fairly soft foods, such as fruit and meat, to tough foods, such as bark and tubers.

The Paranthropus robustus specimen, labelled DNH 155, that is making headlines is significant, because the size of its cranium suggests that its jaw muscles would not have been as strong as that of other specimens of the same species that have been found at the Swartkrans paleoanthropological site.

Researchers have drawn the conclusion that the specimen found at Drimolen hadn’t yet evolved the stronger jaws needed to be able to eat tougher foods.

“That means that the population from Drimolen was not as well adapted to a dry landscape as the later Swartkrans population. We can say that, in only 200 000 years, this species was able to adapt to the climate,” according to the University of Johannesburg statement.

Baker adds that this kind of discovery is particularly helpful as humans today face the prospect of having to adapt quickly to a rapidly changing climate.