Primitive hominid, humans coexisted: study

Humans and primitive hominids lived alongside each other in Africa and may have even exchanged tools, cultural activities and behaviours, new research suggests.

The claims come after fossils belonging to a hominid species called Homo naledi were unearthed in South Africa in 2013.

Researchers made the discovery after wiggling their way through the Rising Star cave system - a network that includes more than 2km of mapped underground passages.

They've now used dating techniques to place the fossils between 236,000 and 335,000 years old.

By contrast, the oldest dated fossils of Homo sapiens in Africa are about 200,000 years old.

It's hoped this new information could broaden the scientific community's understanding about potential interactions between Homo naledi and Homo sapiens.

"This is the first time one of these primitive hominids has been found in association with more modern humans in Africa," Professor Paul Dirks said.

"The new dating of the fossils opens up all sorts of possibilities for an interchange of tool use, cultural activities and behaviours between (the two)."

The refined age range was calculated using 10 different labs and six different techniques, with a lot of the initial work carried out at James Cook University's Advanced Analytical Centre in Douglas.

It suggests tools found in Africa dated back to the Middle Stone Age may not have been the handiwork of Homo sapiens alone.

The research also reinforces the idea that the human evolutionary journey is more complex than a straight-forward, linear history.

But despite the new findings, mystery remains about how the remnants of Homo naledi - which had a brain the size of an orange - got into the cave system in the first place.

"You can speculate all you like, but at the moment the original hypothesis that they were placed there on purpose, still holds," Professor Dirks said.