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Hot, Humid Weather May Have Helped Shape Human Noses

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Noses may be the unsung heroes of the face. We tend to think of them as mere scent collectors, but noses do so much more, including make it possible for humans to survive in different climates all over the world. A study published in the American Journal of Physical Anthropology explores how that may have come about.

Your nose acts like a portable, personal HVAC system, treating the air you inhale to make it easier for your body to process. In the winter, your nose warms the air so that it’s nice and toasty by the time it reaches your lungs. In arid climates, our noses add humidity to our inhalations to keep our respiratory tracts from drying out.

Human nose shape, like skin color, generally varies by latitude. Scientists have suggested that northern Europeans’ thin, pointy noses evolved to help their ancestors process their homelands’ cold, dry air, since narrow nasal passages mean that a greater percentage of inhaled air has to come into contact with heat- and moisture-adding mucous membranes. This, the researchers believed, was the only way the nose has evolved: away from the flatter, wider noses of people living closer to the Equator. The air in those regions is typically hot and humid already, requiring no special treatment. So if the winter nose is a custom job, they said, the summer nose must be the base model.

But "we don't really think that that's true," said biological anthropologist Scott Maddux of the University of North Texas Health Science Center. Maddux and his team used global climate data from 1901 to 2013 to construct maps of average annual temperature and humidity. Then, they compared those with the results of a study from 1923, which measured the noses of more than 15,000 people from 147 countries.

Their results suggest that, rather than a starting point, wider, flatter noses have themselves evolved to help their owners cope in those hot, muggy climates. Humidity is rough on the human body. It makes it much harder for us to shed heat by sweating, so we have to find other ways to cope. One way to do that might be allowing more heat to escape through the two holes in the middle of our face. The wider the nose, the more heat it can funnel out of the body. 

More questions remain. Nearly all the work our noses do takes place inside in a part called the nasal cavity. If it’s the cavity that’s doing the heating and humidifying, Maddux says, why would the outside of our noses need to change at all? To find out, scientists will need to go deeper inside, all the way to our skulls.

Nicholas Holton, a biological anthropologist at the University of Iowa, was not involved in the study but praised the team’s work. "A big part of any face, not just the human face, is the nose," he told Inside Science. "Literally, it's a central component of the skull, so understanding what's happening with the nose may tell us a lot about what's happening with the rest of the face."

[h/t Inside Science]

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Stones, Bones, and Wrecks
The Most Complete Fossil of an Early Human Relative Goes on Display
AFP, Stringer, Getty Images
AFP, Stringer, Getty Images

Twenty years after it was discovered in an African cave, one of the most important fossils in the quest to demystify human evolution is finally on display. As Smithsonian reports, Little Foot, an Australopithecus specimen dating back more than 3 million years, was revealed to the public this month at the Hominin Vault at the University of the Witwatersrand’s Evolutionary Studies Institute in Johannesburg, South Africa.

Paleontologist Ron Clarke discovered the first bone fragments from the fossil in 1994. The pieces came from the remains of a young female’s feet, hence the nickname. Clarke and his team spent years excavating Little Foot bit by bit from the Sterkfontein cave system in South Africa until the bones were fully removed in 2012. The shattered remains had been embedded in a concrete-like material called breccia, making them incredibly tricky to recover. But the sum of the parts is monumental: Little Foot is the most complete Austrolopithecus fossil known to science.

The hominid genus Austrolopithecus played an essential early role in the chain of human evolution. Lucy, another famous hominid fossil, is a member of the same genus, but while Lucy is only 40 percent complete, Little Foot retains 90 percent of her skeleton, including her head. It’s also possible that Little Foot surpasses Lucy in age. Most paleontologists agree that Lucy lived about 3.2 million years ago, while one analysis places Little Foot’s age at 3.67 million years.

Austrolopithecus is believed to have spawned Homo, the genus that would eventually contain our species. The discovery of Lucy and other fossils have led scientists to designate East Africa as the cradle of human evolution, but if Little Foot is really as old as tests suggest, then South Africa may deserve a more prominent point in the timeline.

Following Little Foot’s public debut, the team that’s been studying her plans to release a number of papers exploring the many questions her discovery raises.

[h/t Smithsonian]

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NM Museum of Natural History & Science
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Scientists Find a 245-Million-Year-Old Horseshoe Crab Fossil That Resembles Darth Vader
NM Museum of Natural History & Science
NM Museum of Natural History & Science

Horseshoe crabs have scuttled through Earth’s shallow ocean waters for hundreds of millions of years, but scientists recently discovered the fossil of one that looks like it’s from a galaxy far, far away. As Newsweek reports, the 245-million-year-old creature’s shell is shaped like Darth Vader’s helmet, which prompted researchers to name the prehistoric critter Vaderlimulus tricki. (Tricki pays homage to Trick Runions, the man who found the fossil.)

Paleontologists from the New Mexico Museum of Natural History and Science and the University of Colorado described the Vader horseshoe crab in a new report published in the German journal Neues Jahrbuch für Geologie und Paläontologie. Discovered in Idaho, Vaderlimulus tricki lived during the late Triassic era and belonged to a now-extinct family called Austrolimulidae. During its lifetime, it inhabited the western coast of the supercontinent Pangea.

Vaderlimulus tricki's unique shell can be chalked up to evolution, scientists explain in a news release, as the creatures were “expanding their ecological range from marine into freshwater settings during the Triassic and often exhibit body modifications that provide them with a bizarre appearance by modern standards."

Horseshoe crabs have survived at least 470 million years on Earth, and are often referred to as “living fossils.” But individual species died out over the millennia (only four are currently alive today), and fossils of horseshoe crabs are few and far between. When new ones are discovered, they often belong to a species that was previously unknown to science. Vaderlimulus tricki, in particular, is the first horseshoe crab from the Triassic period to have been found in North America.

[h/t Newsweek]

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