Two million-year-old skull of human cousin found in South African cave
Updated 13:32, 14-Nov-2020
The two-million-year-old skull is a Paranthropus robustus specimen. /La Trobe University

The two-million-year-old skull is a Paranthropus robustus specimen. /La Trobe University

Australian researchers say a two-million-year-old skull found in a South Africa cave provides more information about human evolution, the BBC reported.

The skull is reportedly from Paranthropus robustus, a close relative of Homo erectus, which is thought to be the direct ancestor of modern humans. Paranthropus robustus and Homo erectus lived at the same time, but the Paranthropus robustus died out much earlier.

The team says the new findings are exciting. "Most of the fossil record is just a single tooth here and there so to have something like this is very rare, very lucky," palaeoanthropologist Dr. Angeline Leece told the BBC.

Researchers at Melbourne's La Trobe University discovered the skull fragment at the Drimolen archaeological site north of Johannesburg, South Africa, in 2018. In 2015, a skull of Homo erectus, a child, was found a few meters away from the site.

Over the past few years, archaeologists have pieced together and analyzed the fossils. Their findings were published in the November 10, 2020, issue of Nature Ecology and Evolution.

Three early humans are said to have lived in South Africa at the same time and competed with each other, the report said. In this regard, the skull's discovery is a rare example of "microevolution" within the human lineage, said co-researcher Jesse Martin to the BBC.

Paranthropus robustus had large teeth and a small brain, different from the small brain teeth of Homo erectus. The former is believed to eat mainly hard plants, such as tubers and tree bark.

"Through time, Paranthropus robustus likely evolved to generate and withstand higher forces produced during biting and chewing food that was hard or mechanically challenging to process with their jaws and teeth," said Dr. Leece.

Scientists also said climate change may have reduced the food supply of the Paranthropus robustus by making the environment wetter.

Meanwhile, Homo erectus, with their smaller teeth, was more likely to have eaten both plants and meat.

Dr. Leece said these two vastly different species represent divergent evolutionary experiments.

"While we were the lineage that won out in the end, two million years ago the fossil record suggests that Paranthropus robustus was much more common than Homo erectus on the landscape," she said.