Drimolen Fossil Backs Homo erectus Origin in South Africa
A child’s skull first showed that Homo erectus may have appeared in southern Africa two million years ago. Now an adult fossil from the same cave system adds to that case.
La Trobe University archaeologists, with colleagues from South Africa and the United States, have described 18 new hominin fossils from the Drimolen Main Quarry in South Africa’s Cradle of Humankind. Many fossils excavated there between its discovery in 1992 and 2019 had never been published. The team attributes the 18 fossils to Homo erectus and Paranthropus robustus. Their paper appeared in Annals of Human Biology and was released on September 26.
The adult fossil
The key specimen is DNH 127, the first fossil from an adult Homo erectus at Drimolen, dated to 2 million years ago. The earlier Drimolen fossil, DNH 134, belonged to a child aged between two and four, so researchers were unsure what an adult would look like. Lead researcher Jesse Martin said DNH 127 provides further confirmation that the species first appeared in southern Africa 2 million years ago. The release says this is 200,000 years older than other adult Homo erectus fossils elsewhere, such as those at Dmanisi in Georgia, which date to 1.8 million years ago.
Two species, one landscape
The fossils also show that P. robustus changed over time. Between 2 million and 1.8 million years ago it evolved larger teeth and chewing muscles, which the team calls microevolution. Martin says that while Homo erectus evolved larger brains and smaller molars, possibly linked to meat eating, P. robustus kept a brain only slightly larger than a chimpanzee’s and developed massive molars to process tough and hard foods, like a mortar and pestle.
The two species shared the same landscape. At Drimolen, P. robustus outnumbered Homo erectus by more than 10 to one at that time, so Martin said our ancestors looked like the outside long-odds chance to survive.
A note on the claim
The headline claim that Homo erectus first appeared in southern Africa comes from the La Trobe researchers’ own interpretation. The release is not independent confirmation, and other researchers may weigh the evidence differently.
Sources
Related Articles
