Dinosaurs Had Dandruff Problems, Too

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One of the most compelling aspects of paleontology is its ability to surprise even the most well-versed dinosaur scholars. Every fossil holds the potential to shed new light on how these prehistoric creatures lived, ate, and thrived.

Now, scientists have learned some dinos would have benefited from a medicated shampoo.

A study published in Nature Communications examining 125-million-year-old fossils discovered in China demonstrates that dinos expressed a condition common to humans: Their skin would flake off, creating tiny dandruff specks. The paper helps provide an explanation for how dinosaurs managed to molt, or shed skin in an effort to create tougher exterior tissue.

The specimens consisted of skin and feathers from three different non-avian dinosaurs—the crow-sized Microraptor and the larger Beipiaosaurus and Sinornithosaurus—and one bird, Confuciusornis, all from the Early Cretaceous period. The feathers were dotted with white, 1-2 millimeter blobs that initially puzzled scientists, who eventually visualized them with an ion beam microscope. Researchers confirmed them to be flakes of skin composed of corneocytes, tough cells containing keratin. The flecks suggested that these dinosaurs molted by shedding skin like modern birds instead of casting off chunks of skin like other reptiles.

The corneocytes of today's birds contain fats and loosely packed keratin, which allows birds to stay cool during heat-intensive activity like flying. The dino corneocytes were densely packed with keratin, and they probably wouldn't have provided much of a cooling effect. That tells scientists that the bird-like dinosaurs didn't spend too much time in the air.

If they didn't fly, why the feathers? It probably had to do with keeping warm and providing camouflage from both predators and prey. Researchers hope to continue their studies on the plumage to see what else they can learn.

[h/t Popular Science]

After 20 Years, the Largest Dinosaur Foot Ever Discovered Has Been Identified

In 1998, paleontologists unearthed a fossil in Wyoming that experts agree is still the largest dinosaur foot ever discovered. Comprising 13 bones, the nearly complete fossil is 3 feet wide. And researchers say they've finally figured out who it belonged to.

As Gizmodo reports, the massive foot was likely that of a brachiosaur that roamed the Black Hills mountain range 150 million years ago. Brachiosaurs were sauropods that used their long necks to reach vegetation growing up to 40 feet off the ground. They could grow 80 feet long and weigh 88 tons.

The process of identifying the foot, which researchers explain in the journal PeerJ, took so long only because paleontologists in the West are digging up more fossils than they have time to study. When they finally got around to examining the foot bones, they made CGI models of them with a 3D scanner and compared them to other known examples of sauropod feet.

Though they're confident the foot comes from a brachiosaur—any member of the genus Brachiosaurus—scientists haven't been able to link it to one specific species.

This may be the biggest foot fossil ever found, but that doesn't necessarily make this species of brachiosaur the dinosaur with the largest shoe size. Foot fossils are rare: Because they're smaller and they're extremities, feet are more likely to be washed away or picked off by scavengers than other parts of the body. So while titanosaur and argentinosaurus, the largest known dinosaurs, almost certainly had more colossal feet than this brachiosaur, their actual foot fossils have yet to be discovered.

[h/t Gizmodo]

Fossilized Footprints Show Ice Age Hunters Ganged Up on Giant Sloths

Courtesy of Bournemouth University
Courtesy of Bournemouth University

They just don't make sloths like they used to. Giant ground sloths from the Ice Age wielded razor-sharp claws and stood 7 feet tall, and new evidence suggests that humans—even children—stalked and hunted them.

By analyzing fossilized footprints found in the salt flats of New Mexico, researchers at Bournemouth University in the UK figured out how prehistoric humans managed to outsmart these furry behemoths. The tracks, which are between 10,000 and 15,000 years old, show two overlapping sets of footprints belonging to both man and beast. Researchers deduced that these early hunters aligned their footprints with the sloth's to avoid detection and sneak up on their prey. The findings were published in the journal Science Advances.

Human footprints inside of a larger sloth footprint
Courtesy of Matthew Bennett, Bournemouth University

"Getting two sets of fossil footprints that interact, that show you the behavioral ecology, is very, very rare," Matthew Bennett, one of the researchers at Bournemouth, told Reuters.

They also found another set of human footprints, leading researchers to believe that hunters traveled in packs and ganged up on the sloth, with one group distracting the animal from a safe distance while another attempted to land a fatal blow. The clue was in marks they dubbed "flailing circles," which suggested that the sloth rose on its hind legs and swung around to defend itself. Anywhere they found flailing circles, human footprints followed.

The presence of children's tracks also showed that hunting was a family affair, but it probably wasn't as fun (or as safe) as going to a modern-day zoo. The prints were taken from New Mexico's White Sands National Monument, which has the "largest concentration of human and Ice Age giant megafauna prints in the Americas," according to researchers. The remote part of the park where they conducted their research is not open to the public.

Modern sloths are related to the giant ground sloth, which went extinct about 11,000 years ago, likely due to over-hunting by humans, scientists say. The fossilized footprints were digitized and preserved for future research using 3D modeling techniques.

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