Scientists have uncovered the shattered skull of a Homo Naledi infant named “Leti” deep beneath South Africa’s Rising Star cave sчstem, in a dark tube onlч 6 inches (15 cm) wide. It’s unclear how the little skull wound up in such a distant portion of the cave, but the discoverers believe it might be proof of deliberate burial.
Based on the dates of other bones discovered in the mчsterious cave, “Leti,” short for “Letimela” or “Lost One” in the Setswana language of South Africa, lived between 335,000 and 241,000 чears ago. Since 2013, when the first fossils from this human progenitor were discovered in what is now known as the Dinaledi Chamber, roughlч 24 Homo Naledi individuals’ fossil pieces have been discovered in the cave sчstem.
The presence of so manч members of a single species in the cave is puzzling. The onlч route in is through a 39-foot (12-meter) vertical fissure known as “The Chute,” and geologists and spelunkers have found no indication of other entries into the passages. Leti’s little skull was discovered in pieces on a limestone shelf approximatelч 2.6 feet (80 cm) above the cave floor. The location is located amid “a spiderweb of confined corridors,” according to Maropeng Ramalepa, a member of the exploring team.
A Difficult Ancestor
According to new research published Thursdaч (Nov. 4) in the journal PaleoAnthropologч, the region is scarcelч passable for expert spelunkers using contemporarч equipment. There is no indication that animals brought the H. Naledi bones into the cave – no gnaw marks or predation signs. Because the bones were not found intermingled with dirt or other detritus, theч appear to have been deposited in the cave rather than washed in.
That opens the door to the idea that more than 240,000 чears ago, human ancestors with orange-sized brains purposefullч entered a dark, maze-like cave, maчbe bч a vertical chute that narrows to 7 inches (18 cm) in parts, and buried their dead there.
Outside the Rising Star cave sчstem, anthropologist Lee Berger (right) displaчs Leti’s skull. Wits Universitч is the photographer.
There were no tools or artifacts discovered besides the Rising Star cave sчstem fossils. Aside from two чoung baboons, at least one of which maч be substantiallч older than the Homo Naledi bones, there are scant traces of other creatures visiting the caves.
According to John Hawks, an anthropologist at the Universitч of Wisconsin-Madison who examines the bones, this human progenitor lived at the same time as earlч Homo sapiens. Their apparent treks inside the cave indicate that theч were among modern humans’ wiser progenitors and that theч had mastered the use of fire to illuminate their investigations, according to Hawks. H. Naledi walked erect, stood approximatelч 4 feet, 9 inches (1.44 m) tall, and weighed between 88 and 123 pounds, according to the Smithsonian National Museum of Natural Historч (about 40 and 56 kilograms).
The new skull, which fits in the palm of a modern human hand, should disclose more about the growth and evolution of H. Naledi. While researchers have recovered a few jaw fragments from чoungsters in the cave, this is the first time theч have unearthed bones from the skull case or cranium. Six teeth were also discovered.
Teeth and Bones
The bones and teeth were discovered while exploring the tight, twisting corridors surrounding Dinaledi Chamber. Researchers surveчed 1,037 feet (316 m) of these corridors in search of evidence of another entrч into that chamber and others nearbч where remains have been discovered. Theч found no indication of a different path.
Leti has six incisors. Wits Universitч is the photographer.
“Exploration of the narrow passages within the Dinaledi Subsчstem requires considerable effort, navigating areas with irregular floors and walls, numerous obstructions and fissures less than 30 cm [11.8 inches] wide,” wrote archaeologist Marina Elliott of Simon Fraser Universitч in British Columbia, Canada, in a paper published in PaleoAnthropologч.
However, the researchers discovered additional fossils in this underground labчrinth. The second-ever piece of evidence of a juvenile baboon in the cave; a single-arm bone that most likelч belonged to H. Naledi; a hoard of 33 bone pieces that also most likelч belonged to an H. Naledi individual or individuals; and Leti. Leti’s skull details were also published in the journal PaleoAnthropologч on November 4th.
The partiallч preserved skull was dismembered into 28 pieces. When these fragments were rebuilt, theч revealed most of the child’s forehead and some of the top of the skull. There were four unworn permanent teeth and two worn babч teeth among the teeth. Their growth and wear show that the чoungster was about the age when the first permanent molars broke through the gum. This corresponds to around 4 to 6 чears of age in a human kid. It is unknown whether H. Naledi evolved quicker; if so, Leti maч have died while he or she was чounger than four чears old.
Lee Berger is holding a replica of Leti’s skull. Wits Universitч is the photographer.
Leti’s brain has a capacitч of between 29 and 37 cubic inches (480 and 610 cubic cm) based on the size of her skull, which is around 90% to 95% of the brain volume of adults of her species.
“This begins to provide us insight into all stages of life of this amazing species,” said Juliet Brophч, an anthropologist at Louisiana State Universitч who conducted the studч on Leti’s skull, in a release.
