- 3364 - FOSSILS - Oldest fossils found in Africa? In an African cave scientists have discovered the fragmented skull of a “Homo naledi” child they're calling "Leti." How the little skull ended up in such a remote part of the cave is a mystery, though the discoverers suspect it could be evidence of an intentional burial, 240,000 years ago.
--------------------- 3364 - FOSSILS - Oldest fossils found in Africa?
- Oldest fossils that are not in our Coffee Club. Fossils not found at the Starbucks cave system. These fossils were found deep within South Africa's “Rising Star” cave system, in a dark passageway barely 6 inches wide.
-
- The fragmented skull of a “Homo naledi” child they're calling "Leti ended up in a remote part of the cave. The discoverers suspect it could be evidence of an intentional burial.
-
- "Leti," short for "Letimela," or "Lost One" in the Setswana language of South Africa, probably lived between 335,000 and 241,000 years ago, based on the ages of other remains found in the enigmatic cave.
-
- Fossil fragments belonging to about 24 “Homo naledi” individuals have been found in the cave system since 2013, when the first fossils from this human ancestor were discovered in what's now known as the Dinaledi Chamber, ancestor to Starbucks Chamber.
-
- The presence of so many individuals from a single species in the cave is mysterious. The only way in is a 39-foot vertical fracture known as "The Chute," and geologists and spelunkers have so far found no evidence of alternative entrances into the passageways.
-
- Leti's small skull was found scattered in pieces on a limestone shelf about 2.6 feet above the cave floor. The spot sits in a spider web of cramped passages. Leti's skull fits into the palm of a modern human hand.
-
- Teeth from the Homo naledi child "Leti" indicate that Leti died around the time of the eruption of the first permanent molars, which would be between the ages of 4 and 6 in modern humans.
-
- The skull probably dates back more than 241,000 years.
-
- The area inside the cave is barely navigable for experienced spelunkers with modern equipment. There is no evidence that animals carried the H. naledi bones into the cave. There are no gnaw marks or evidence of predation. The bones also appear to have been placed in the cave, not washed in, as they were not found mixed with sediment or other debris.
-
- That leaves open the possibility that more than 240,000 years ago, human ancestors with orange-size brains deliberately entered a dark, maze-like cave, perhaps through a vertical chute that narrows to 7 inches in places, and placed their dead inside.
-
- No tools or artifacts have been found alongside the Rising Star cave system fossils. There are few signs of other animals entering the caves, beyond two specimens of juvenile baboons, at least one of which may be much older than the Homo naledi remains.
-
- This little human ancestor lived at the same time as early Homo sapiens. Their apparent forays into the cave suggest that they were among modern humans' smarter ancestors, and that they had mastered the use of fire to light their explorations. H. naledi walked upright, stood about 4 feet, 9 inches tall and weighed between 88 and 123 pounds.
-
- The new skull, which fits into the palm of a modern human hand, should reveal more about H. naledi's growth and development. While a few jaw fragments from juveniles have been found in the cave, this is the first time researchers have discovered bones from the skull case, or cranium. They also discovered six teeth.
-
- The bones and teeth were found during an exploration of the narrow, twisting passageways around Dinaledi Chamber. Researchers mapped 1,037 feet of these passageways, looking for evidence of another way into that chamber and several others nearby where remains have been found. They saw no evidence of another route.
-
- Exploration of the narrow passages within the Dinaledi Subsystem involves considerable effort, navigating areas with irregular floors and walls, numerous obstructions and fissures less than 30 cm wide..
-
- The researchers did find more fossils in this subterranean maze. These included the second-ever piece of evidence of a juvenile baboon in the cave; a single arm bone probably belonging to H. naledi; a trove of 33 bone fragments that also likely belonged to an H. naledi individual or individuals; and Leti.
-
- The partially preserved skull was broken into 28 fragments. When reconstructed, these fragments revealed much of the child's forehead and some of the top of the head. The teeth consisted of four unworn permanent teeth and two worn baby teeth. Their development and wear indicate that the child was at the age where the first permanent molars were breaking through the gum.
-
- In a human child, this would correspond to about 4 to 6 years of age. It's not known if H. naledi developed faster; if so, Leti may have been younger than 4 when he or she died.
The size of the skull indicates that Leti's brain had a volume of between 29 and 37 cubic inches about 90% to 95% of the brain volume of adults of her species.
-
- First identified a little more than a decade ago, the Denisovans, an extinct branch of the human family tree, are the closest known relatives of modern humans, along with Neanderthals.
-
- Analysis of DNA extracted from Denisovan fossils suggests they might have once been widespread across continental Asia, island Southeast Asia, and Oceania, and revealed that at least two distinct groups of Denisovans interbred with ancestors of modern humans.
-
- Until now, scientists had only discovered half a dozen Denisovan fossils. Five were unearthed in Denisova Cave in Siberia, and one was found in a holy site in China.
-
- Researchers examined 3,791 bone scraps from Denisova Cave. They looked for proteins they knew were Denisovan based on previous DNA research on the extinct lineage. Among these scraps, the scientists identified five human bones.
-
- Four of these bones contained enough DNA to reveal their identity, one was Neanderthal, and the other three were Denisovan. Based on genetic similarities, two of these fossils may either come from one person or from related individuals.
-
- The researchers estimated the age of these Denisovan fossils based on the layer of earth in which they were uncovered. This layer also contained a slew of stone artifacts and animal remains, which may serve as vital archaeological clues on Denisovan life and behavior.
-
- These findings suggest these newfound Denisovans lived during a time when, according to previous research, the climate was warm and comparable to today, in a locale favorable to human life that included broad-leaved forests and open steppe.
-
- Butchered and burnt animal remains found in the cave suggest the Denisovans may have fed on deer, gazelles, horses, bison, and woolly rhinoceroses. The stone artifacts found in the same layer as these Denisovan fossils are mostly scraping tools, which were perhaps used for dealing with animal skins.
-
- The raw material for these items likely came from river sediment just outside the entrance to the cave, and the river likely helped the Denisovans when they sought to hunt.
-
- The stone tools linked with these new fossils have no direct counterparts in north or central Asia. However, they do bear some resemblance to items found in Israel dating between 250,000 and 400,000 years ago, a period linked with major shifts in human technology, such as the routine use of fire.
-
- Denisovans may not have been the only occupants of the cave at this time. Bones of carnivores such as wolves and wild dogs suggest Denisovans may have actively competed with these predators over prey and perhaps the cave itself.
-
November 30, 2021 - FOSSILS - Oldest fossils found in Africa? 3364
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ---
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
--------------------- --- Friday, December 3, 2021 ---------------------------
No comments:
Post a Comment