Researchers have discovered the first skull remains of a child of an extinct species, adding further to the mystery of why ancient remains are found deep in a remote South African cave system.
Professor Eric Roberts from James Cook University took part in the exploration of the Rising Star Cave system where remains of a new species, Homo naledi, were first found in 2015. He says the discovery of parts of the skull and teeth of a 4 to 6-year-old Homo naledi child in the remote depths of the cave system will help researchers better understand the extinct species.
“We’ve found almost 2000 fragments of Homo naledi in the caves, but they are very difficult to access. You crawl several hundred metres into the cave system through some very narrow squeezes. It requires a technical rock climb and you hyperventilate a bit going down.”
He said scientists don’t believe there has ever been an easier way to access the caves and don’t believe the bones of the hominids were moved there by floods or other geological processes.
Dr Roberts said the child was found in an extremely remote passage of the system, some 12 meters beyond the site of the original site of discovery of Homo naledi remains.
Marina Elliott, who was part of the team that recovered the remains and lead author on one of the papers, describes the area where the skull was found as “extraordinarily difficult, perhaps the most difficult site with hominin fossils we have had to get to” and a place where “only the most experienced cavers and scientists can reach”.
The child’s skull was found alone, and no remains of its body have been recovered. The team has named the child “Leti” (pronounced Let-e) after the Setswana word “letimela” meaning “the lost one”.
Juliet Brophy from Louisiana State University led the study of Leti’s skull and dentition. “These are the first skull remains of a child of Homo naledi yet recovered and this begins to give us insight into all stages of life of this remarkable species,” she said.
It has yet to be established how ancient Leti’s remains are, but Tebogo Makhubela, one of the team’s geologists said “Since fossils of Homo naledi from the nearby Dinaledi Chamber have been dated to between 335 and 236 thousand years ago, it’s likely Leti is of a similar age based on preservation and proximity.”
It is not known how Leti’s skull came to rest, alone, in such a remote and inaccessible part of the system and the authors hypothesise that it is likely other members of its species were involved in the skull reaching such a difficult place.
Project leader Lee Berger said work is continuing throughout the cave system and that new discoveries are likely to shed further light on whether these chambers and passages are in fact a burial ground of Homo naledi.
“It’s just another riddle among many that surrounds this fascinating extinct human relative,” he said.
