Evolution and humans: Neanderthal lungs larger (Evolution)

by David Turell , Tuesday, October 30, 2018, 19:25 (2214 days ago) @ David Turell

The Neanderthal rib cage was attached a little differently to a straighter thoracic spine, with a larger diaphragm implied by the rib anatomy:

https://phys.org/news/2018-10-reconstructs-neandertal-ribcage-clues-ancient.html

"An international team of scientists has completed the first 3-D virtual reconstruction of the ribcage of the most complete Neandertal skeleton unearthed to date, potentially shedding new light on how this ancient human moved and breathed.

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"Using CT scans of fossils from an approximately 60,000-year-old male skeleton known as Kebara 2, researchers were able to create a 3-D model of the chest—one that is different from the longstanding image of the barrel-chested, hunched-over "caveman." The conclusions point to what may have been an upright individual with greater lung capacity and a straighter spine than today's modern human.

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"The reconstruction of the thorax, coupled with the team's earlier finding, shows ribs that connect to the spine in an inward direction, forcing the chest cavity outward and allowing the spine to tilt slightly back, with little of the lumbar curve that is part of the modern human skeletal structure. "The differences between a Neandertal and modern human thorax are striking," said Markus Bastir, senior research scientist at the Laboratory of Virtual Anthropology at the National Museum of Natural History in Spain.

"'The Neandertal spine is located more inside the thorax, which provides more stability," said Gomez-Olivencia. "Also, the thorax is wider in its lower part." This shape of the rib cage suggests a larger diaphragm and thus, greater lung capacity.

"'The wide lower thorax of Neandertals and the horizontal orientation of the ribs suggest that Neandertals relied more on their diaphragm for breathing," said senior author Ella Been of Ono Academic College. "Modern humans, on the other hand, rely both on the diaphragm and on the expansion of the rib cage for breathing. Here we see how new technologies in the study of fossil remains is providing new information to understand extinct species."

"What that means for how Kebara 2 lived is ripe for further research, Kramer said. How did Neandertals breathe, and for what physical demands might they have needed powerful lungs? What does that tell us about how they moved, and the environment in which they lived? Did any of these physical traits make them more or less adaptive to climate change?

"Reconstructing the thorax was an exercise in starting from scratch, deliberately trying to avoid being influenced by past theories of how Neandertals looked or lived, Kramer said."

Comment: It is not surprising to find anatomic differences between the species.