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Pterosaurs Keep Just Getting Weirder

Experts often use the word "bizarre" to describe the pterosaurs, the winged dragon that ruled the sky for more than 160 million years. This is especially true for the group of short-tailed pterosaurs called anurognathids, which used to baptize and bubble through mesozoic era forests like bats, hawking for insects. Now it appears that anurognathids and other pterosaurs may have carried a strange varied rock of feathers and fur-like structures, according to a new study published Monday in Nature Ecology & Evolution. A group led by paleontologist Zixiao Yang from Nanjing University in China reached the conclusion based on two nearly finished pigeon-sized anurognathid pterosaur samples found in northern China. The idea that pterosaurs (which lived from about 228 million years ago to the Cretaceous eradication 66 million years ago) may have had some form of furilayer is not new in itself. Researchers have suggested so much since the discovery of the first known pterosaurs in the 1 9th century. But the exact character of this coverage has been difficult to determine from the short, filamentous structures-called pycnofibres – preserved in pterosaur fossils. The new study was to fill that gap with the help of a battery of advanced technical tools. As a result, the authors characterize what they say are four different types of pycnofibers, distributed around the animal's body in different ways, suggesting different types of pycnibbers performed different functions: heat insulation on the neck and head, for example, or reducing drag on wings. One type of pycnofiber…

Experts often use the word “bizarre” to describe the pterosaurs, the winged dragon that ruled the sky for more than 160 million years. This is especially true for the group of short-tailed pterosaurs called anurognathids, which used to baptize and bubble through mesozoic era forests like bats, hawking for insects.

Now it appears that anurognathids and other pterosaurs may have carried a strange varied rock of feathers and fur-like structures, according to a new study published Monday in Nature Ecology & Evolution. A group led by paleontologist Zixiao Yang from Nanjing University in China reached the conclusion based on two nearly finished pigeon-sized anurognathid pterosaur samples found in northern China.

The idea that pterosaurs (which lived from about 228 million years ago to the Cretaceous eradication 66 million years ago) may have had some form of furilayer is not new in itself. Researchers have suggested so much since the discovery of the first known pterosaurs in the 1

9th century. But the exact character of this coverage has been difficult to determine from the short, filamentous structures-called pycnofibres – preserved in pterosaur fossils. The new study was to fill that gap with the help of a battery of advanced technical tools. As a result, the authors characterize what they say are four different types of pycnofibers, distributed around the animal’s body in different ways, suggesting different types of pycnibbers performed different functions: heat insulation on the neck and head, for example, or reducing drag on wings. One type of pycnofiber is a simple hair-hard monofilament. But three others seem to be branched in a way that the authors describe as “remarkably similar” to bird feathers. The similarities go beyond the form or morphology, they say, to resemble chemical and cellular levels.

Based on this result, the study argues that “feather-like branch integrity structures” may have been developed first in dinosaurs, as generally thought, but in any primordial archosaur-a common ancestor of both pterosaurs and dinosaurs, including modern birds. This would mean that the ancestor even of certain nonavian dinosaurs like Stegosaurus may have been covered with quills, rather than dare. It would also drive the springs’ origins from the jungle era and back 60 million or 70 million years to the start of the Triassic period.

The early date for the appearance of feathers would fit, says Michael Benton, senior author of the new study and a paleontologist at the University of Bristol in England, with the transition from a spreading to upright posture and to warm blood in many animal groups – along with Other evidence indicating “the pace of life increased” as trias species struggled to recover from Permian-Triass mass eradication, where 70 percent of the land vertebrates had disappeared about 252 million years ago. It would also be appropriate that most genes controlling feather production were present in vertebrates prior to the origin of dinosaurs.

The mot argument, Benton says, are the great dinosaurs like Stegosaurus or Brontosaurus missing springs. But it is no stranger, he says than elephants or whales who have little or no hair – although both developed long after the development of the hair in mammals.

In a comment published in the same issue, behavioral ecologist Liliana D & # 39; Alba at the Ghent University of Belgium, who was not involved in the new study, is still skeptical. The study shows that the chemical composition of pyknofib resembles the springs, she wrote, and both scanning electron microscopy and energy-dispersing X-ray spectroscopy show that the fibers contain melanosomes – the same pigment pack that gives color to feathers and mammal hairs. But the claim that some pycnofibers are branched as feathers are based, she says, on subjective interpretation of “gross filament morphology” or form. She notes that an earlier attempt by other researchers to characterize pycnofibers as featherlike failed to convince most paleontologists. It may require the development of other advanced technologies, she suggests, solving the issue.

“Does this work show that the archosaur skin was more complex than we knew? Yes, says Yale ornithologist Richard Prum, whose extensive knowledge about feathers was the foundation of his award-winning 2017 book The Evolution of Beauty . (Prum was also not involved in the new study.) “Are archosaurs showing all sorts of interesting things from their skin? You bet. All you have to do is look at a turkey beard to see that completely new things can develop on an archosaur’s skin. “But Prum says that the authors’ great conclusion is” wrong “because they ignore this evolutionary keyness for novelty. Just because the pterosaurs produced some strange featherlike structures do not automatically mean that feathers must have occurred in any common ancestor of pterosauria and dinosaurs.” These pterosauria is cool, “says Prum,” but their branched structure is not homologous to the feather “, that is, they do not have a common evolutionary origin.” And they are probably not homologous with springs at all, “he says.” In short, they do not spring. “

Most are not even pigeon fibers, says pterosaur specialist David Unwin at the University of Leicester, England, which was not involved in the study.” These are amazing copies, and they did a brilliant job of depict them, “he adds. However, he argues that scientists suspect that they use keratin content to identify certain structures as external p fibrous fiber. These structures, he says, are almost certainly pterosaurs called actin fibers, which can also contain keratin. None of the new study’s nine writers have experience of tissue protection in pterosauria; Perhaps, as a result, Unwin says that they do not refer to other relevant studies, such as pterosaur melanosomes. Their interpretation of the evidence, he adds, “is problematically said at least”.

Benton challenges critics to show “the structures of the pterosaurs are morphologically or chemically different from feathers.” At the same time, he says “we take a parsimonical view” that they are actually feathers. He resembles the new study to set up a dragon: “We are just about to establish a hypothesis that can be tested.”

Attempt to bring down the dragon of rhetorical shotgun fire – has now begun.

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