[ad_1]
NOTThe eandertal are among the worst victims in the history of bad public relations. As we continue to discover, Neanderthals were not raw and uncultivated hominines, but a complex species with sophisticated tools, engravings, and attitudes towards strangers – even though they tended to consanguinity. A PNAS study published Monday eliminates another misconception that we Homo sapiens have always dominated them: their terrible posture.
The representations of Neanderthals in pop culture generally show an individual with large, curved eyebrows, who looks more like a great four-legged monkey than a standing man. This reputation comes from a single skeleton of a old people Neanderthal discovered at La Chapelle-aux-Saints in France, described in 1911 by Marcellin Boule. But as revealed by a new virtual reconstruction of the Neanderthal skeleton, he and his loved ones had the type of skeleton that could walk as perfectly straight as any human being in good posture today.
The idea that Neanderthals have a right spine "is absurd in biomechanics".
"I've always been convinced that our ancestors, as well as the Neanderthals, never walked with a semi-erect posture, which is not biomechanically adequate," senior author Martin Haeusler, Ph.D., Head of the Evolutionary Morology Group at the University of Zurich, tells reverse. "Similarly, the current reconstruction of Neanderthals by some of our colleagues showing a straight spine without the marked sinusoidal curvature of modern humans is biomechanically absurd."
Right spine against the curved spine
If the Neanderthals walked with a presentiment, as the old drawings suggested, they would have had straight spines. But the computer model created by Haeusler and his team shows that Neanderthals, like Homo sapiens, actually had a curved lower spine (lumbar region) and neck. By examining the wear marks on the vertebrae composing these regions, they were able to reconstruct the vertical posture of Neanderthal.
Lumbar curvature, as explained by the Smithsonian National Museum of Natural History, absorbs the shock of standing up and is "only human" (ie, Homo family).
They also noticed that the Neanderthal man's sacrum – the triangle-shaped bone located between the hip bones – was positioned the same way as in humans. The sacrum supports all the weight of the upper body, so that its position relative to the rest of the pelvis also shows the upper body orientation. Wear marks on the hip joints added further evidence that Neanderthals were walking tall.
How Ball made his mistake
When he found Neanderthal's skeleton in 1908, Boule did not exactly have the context for his discovery. "Boule thought that the Neanderthals were somehow an intermediary between great apes and recent humans. In the time of Ball, there was no other fossil human ancestor, "says Haeusler.
"Based on his preconceptions, he interpreted the differences in skeletal anatomy compared to recent humans as primitive," he says. In doing so, Boule did not consider the possibility that Neanderthal's spine is unusual for Neanderthals – nor the possibility that it is simply old.
"He did not take into account the morphological variation in modern man," Haeusler adds. "Moreover, he did not understand the meaning of the degenerative changes in the spine of La Chapelle-aux-Saints."
The debate continues
In 2018, research published in Nature Communications also used a 3D reconstruction to show that a Neanderthal skeleton discovered in a cave in northern Israel (known as Kebara 2) had a wider rib cage than humans and a "degree" lower curvature ". This paper suggested that the lower Neanderthal spine was straighter than ours, which is more consistent with a curved posture.
Haeusler points out that, in this article, scientists compared the virtual chest of the Neanderthal skeleton to the computed tomography of 16 modern men. As a result, he also failed "to take into account the morphological variation among modern humans".
Erik Trinkaus, Ph.D., professor of anthropology at the University of Washington and co-author of PNAS study, adds that Kebara 2 has "an exceptionally large pool and therefore should have a rather wide lower rib cage" and that it "is not necessarily representative of the Neanderthals".
The problem is therefore to take into account the expected variation of Neanderthals and modern humans.
The debate, which has been going on for decades, continues. Nevertheless, on Monday, Haeusler His team is probably right: "Overall, there is little evidence that Neanderthals have a fundamentally different anatomy." This statement echoes that British researchers, also criticizing Boule's ideas, wrote in 1957 in Quarterly review of biology:
It may well be that the arthritic "old man" of La Chapelle-aux-Saints, the postural prototype of Neanderthal man, actually stood up and walked with a kind of pathological kyphosis; but, if so, he has his counterparts in modern men with the same kind of osteoarthritis of the spine.
And so, it is possible that all the controversy around the Neanderthal spines is reduced to the fact that some Neanderthals, like some humans, simply had a better posture than others. Unfortunately, we do not have a lot of Neanderthal skeletons, so it's important for scientists to keep an open mind when drawing conclusions about the species.
"So the problem is to take into account the expected variation of Neanderthals and modern humans," says Trinkaus.
Abstract: Although the first postural reconstructions of incompletely erected Neanderthals were rejected half a century ago, recent studies of Neandertal vertebral remains have revealed a hypolordotic imbalance, of the lower back and spine, including the skeleton. from La Chapelle-aux-Saints. These studies are part of a continuing trend to view Neanderthals as less "human" than ourselves, despite growing evidence of little or no difference in basic functional and behavioral anatomical abilities. We therefore re-evaluated the vertebral posture of La Chapelle-aux-Saints 1 using a new pelvic reconstruction to infer lumbar lordosis, interarticulation of the lower lumbar (L4-S1) and cervical (C4-T2) vertebrae and taking into account his generalized age. osteoarthritis related. Chapel-aux-Saints 1 has a pelvic incidence (and therefore lumbar lordosis) similar to that of modern humans, an articulation of the lumbar and cervical vertebrae indicating a pronounced lordosis and Baastrup's disease as a product of his advanced age, osteoarthritis and lordosis. Our results question the vision of spinal curvatures, which are generally small in Neanderthals. Excluding the developmentally abnormal Kebara 2 spine, La Chapelle-aux-Saints 1 is joined by other Neanderthals with sufficient vertebral remains to ensure a completely vertical (and human) axial posture.
[ad_2]
Source link