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South African cave yields yet more fossils of a newfound relative


Probing deeper into the South African cave system known as Rising Star, a subterranian maze that last year yielded the largest cache of hominin fossils known to science, an international team of researchers has discovered another chamber with more remains of a newfound human relative, Homo naledi.

South African cave yields yet more fossils of a newfound relative
"Neo" skull of Homo naledi from the Lesedi Chamber is shown [Credit: John Hawks/
University of Wisconsin-Madison]
The discovery, announced May 9, 2017 with the publication of a series of papers in the journal eLife, helps round out the picture of a creature that scientists now know shared the landscape with modern humans -- and probably other hominin species -- between 226,000 and 335,000 years ago. The discovery of the new fossils representing the remains of at least three juvenile and adult specimens includes a "wonderfully complete skull," says University of Wisconsin-Madison anthropologist John Hawks.

Hawks, a leader of the research team at Rising Star and the lead author of the paper describing the new fossils, says finding more remains of multiple individuals in a chamber some distance from the chamber containing the original Homo naledi fossils lends heft to the idea that Homo naledi was caching its dead -- a surprising behavior that suggests great intelligence and possibly the first stirrings of culture.

"This likley adds weight to the hyposthesis that Homo naledi was using dark, remote places to cache its dead," Hawks observes. "What are the odds of a second, almost identical occurrence happening by chance?"

The new chamber, dubbed the Lesedi Chamber, is nearly 100 meters from the Dinaledi Chamber where the first Homo naledi fossils representing at least 15 indivuduals of various ages were found. So far, the team led by Hawks and Lee Berger, a noted paleoanthropologist from the University of Witwatersrand and a senior author of the paper with Hawks, has retrieved more than 130 new Homo naledi fossils from the Lesedi Chamber, a name that means "light" in the Setswana language.

The new chamber is also exceedingly difficult to access, requiring those excavating the fossils to crawl, climb and squeeze their way in pitch dark to the fossil cache.

South African cave yields yet more fossils of a newfound relative
Homo naledi was very different from archaic humans that lived around the same time. Left: Kabwe skull
 from Zambia, an archaic human. Right: "Neo" skull of Homo naledi
[Credit: John Hawks/University of Wisconsin-Madison]
The newly-reported remains were first discovered in 2013 while excavations were underway in the Dinaledi Chamber. The new fossils come from at least three individuals -- two adults and a child -- and the researchers believe more will be recovered as excavations progress. The child, estimated to be under five years of age, is represented by bones from the head and body. Of the adults, one is identified only by a jaw and leg bones.

The skeleton of the third individual, dubbed "Neo" after the Sesotho word meaning "a gift," is remarkably complete. The skull has been painstakingly reconstructed, providing a much more complete portrait of Homo naledi. "We finally get a look at the face of Homo naledi," notes Peter Schmid, who holds a joint appointment at the University of Witwatersrand and the University of Zurich, and who spent hundreds of hours reconstructing the fragile bones of the skull.

"The skeleton of 'Neo' is one of the most complete ever discovered, technically more complete than the famous Lucy fossil given the preservation of the skull and mandible," explains Berger, the University of Witwatersrand paleoanthropologist overseeing the Rising Star excavations.

The skull of the new skeleton has much of the face, including the delicate bones of the inner eye region and nose, says Hawks, an expert on early hominins. "Some of the new bones add detail to what we knew before," says the Wisconsin paleoanthropologist. "The 'Neo' skeleton has a complete collarbone and a near-complete femur, which help to confirm what we knew about the size and stature of Homo naledi, and that it was both an effective walker and climber. The vertebrae are just wonderfully preserved, and unique -- they have a shape we've only seen in Neanderthals."

Combined, the two caches of Homo naledi fossils give science its most complete record of a hominin species other than modern humans and Neanderthals.

"With the new fossils from the Lesedi Chamber, we now have approximately 2,000 specimens of Homo naledi, representing the skeletons of at least 18 individuals," Hawks says. "There are more Homo naledi specimens than any other extinct species or population of hominins except for Neanderthals."

The notion that Homo naledi were caching their dead in underground chambers that are exceedingly difficult to get to has one parallel in Neanderthals. In a deep Spanish cave known as Sima de los Huesos, there is evidence that Neanderthals were caching the bodies of their dead companions 400,000 years ago.

"What is so provacative about Homo naledi is that these are creatures with brains one third the size of ours," Hawks says. "This is clearly not a human, yet it seems to share a very deep aspect of behavior that we recognize, an enduring care for other individuals that continues after their deaths. It awes me that we may be seeing the deepest roots of human cultural practices." 

More information:

Paul HGM Dirks et al. The age of and associated sediments in the Rising Star Cave, South Africa, eLife (2017). DOI: 10.7554/eLife.24231

John Hawks et al. New fossil remains offrom the Lesedi Chamber, South Africa, eLife (2017). DOI: 10.7554/eLife.24232

Lee R Berger et al. , a new species of the genusfrom the Dinaledi Chamber, South Africa, eLife (2015). DOI: 10.7554/eLife.09560

Author: Terry Devitt | Source: University of Wisconsin-Madison [May 09, 2017]
TANN

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3 comments :

  1. Again a spectacular discovery & beautiful description, but unfortunately still the same anthropocentric interpretations. The naledi-lesedi hominids were no efficient walkers, they were probably no closer relatives of Homo than of Pan, and they certainly did not "cach their dead in underground chanbers". Efficiently walking animals such as ostriches don't have plantigrade feet with the first toe bigger & often longer than the other toes: ostriches have narrow & high digitigrade feet, with atrophied outer digital rays, but very long & strong middle digital rays, the opposite of what we see in humans, prenatal chimps, naledi & australopiths, flamingoes, grebes & penguins. In fact, humans have more primitive feet than chimps & bonobos, whose feet near birth become less humanlike & more handlike (C.Coon). These flat feet were not in the first place for walking, but more likely for wading bipedally in the wetlands where many hominids lived: "Reconstructed habitats show that Australopithecus species existed in fairly wooded, well-watered regions. Paranthropus species lived in similar environs and also in more open regions, but always in habitats that include wetlands" (K.Reed 1997 JHE 32:289). Its curved hand-bones suggest frequent vertical climbing in the branches above the the swamps. There's no evidence (apart from anthropocentrism) that naledi-lesedi was a closer relative of us than of chimps or bonobos: its humanlike traits are not human-derived, but hominid-primitive (e.g. chimp fetuses have humanlike feet which near birth become handlike). And of course it's unnecessary to suppose "deliberate burial" of their dead in caves: fossil accumulations are not rare, esp. not in paleo-anthropology, see e.g. the so-called First Family AL-333: "The bones were found in swale-like features ... it is very likely that they died and partially rotted at or very near this site ... this group of hominids was buried in streamside gallery woodland" (Radosevich cs 1992 AJPA 87:15-27). The best illustration of how naledi-lesedi lived are probably bonobos wading bipedally for wetland resources such as waterlilies or sedges, google "bonobo wading": this would explain their flatter feet, vertical climbing, upright posture, small brain, small front teeth etc.

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  2. i find it very hard to believe, even with an exceptionally controlled use of fire that this species deliberately disposed of their dead to an extent such as this in 2 neighboring caves. There was likely a shallow grave in which the contents was washed down in a flash flood into these deep depths. i dont care if it was early as 100k years ago with homo sapiens as their guide, i doubt this species had the luxury of time to learn to care this much given their physique and competition at the time in this landscape. i thought i remember reading with the naledi studies that they somewhat ruled out the washing down of remains due to the positions and local residues but if a one-time torrential rain/flash flood happened, I'm not so sure how this could be entirely ruled out but i do know that and they definitely didnt scuba their way down and these arboreal-ly advantaged hominids certainly didnt have a reason to want to be be avid spelunkers much beyond the entrance of a cave.

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  3. Hi Dean Vios, prof.Dirks emailed that there were no geological indications of a flash-food or so, so this is unlikely. All we know suggests the same: curved handbones = vertical climbing, slightly lengthened handbones, flat feet as in humans & prenatal chimps = wading/swimming (google e.g. "aquarboreal ancestors"), "orange mud-clasts embedded in a brown muddy matrix" & "largely unconsolidated mud-clast breccia" = bodies soon after death covered with mud, small ape-sized brain, rel.long legs = frequent bipedal wading, etc.: naledi spent a lot of time feeding on swamp foods, e.g. waterlilies, papyrus sedges & hard-shelled invertebrates (cf enamel microwear damage), like bonobos do sometimes (google "bonobo wade") but more frequently. No wonder there were no other macro-fauna in the cave. They simply died where they fed, in swamp forests or wetlands, the corpses accumulated in the mud, the underground eroded away & formed caves, and the mud + corpses slid, sank and/or fell in the cave. All completely natural: no need for far-fetched fantasies like "deliberate burial" or "savanna running". Naledi were probably extinct relatives of chimps or bonobos, google e.g. "Pan naledi 2017".

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