Dinosaur Skin Study Reveals That Most Were Scaly Like Reptiles, Not Feathery Like Birds
The link between birds and feathers takes us millions of years back into the Jurassic era when birds evolved from dinosaurs, while dinosaur fossils often give the unmistakable evidence of feathers on their body. Although many animals at the time had feathers, paleontologists have long-debated whether they could fly, as well as whether or not feathers were a common evolutionary trait. Now, a team of scientists is questioning this claim, and saying that the majority of dinosaurs actually had scales instead.
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Paul Barrett of the Natural History Museum in London and David Evans of the Royal Ontario Museum in Toronto conducted an intensive study, creating a database of all known impressions of dinosaur skin tissues. The database enabled the scientists to identify the animals with feathers or feather-like structures, and locate their place in the dinosaurian family tree.
Scientists have known for about 20 years now that theropods, which include Tyrannosaurus and Velociraptors, are the source of bird's evolution -they too were feathered animals. The results of the study show that some ornithischians, such as the Psittacosaurus and Tianyulong, also had quills or filaments in their skin. However, the overwhelming majority of the dinosaurs had scales, or armor, including the long-necked sauropods. The findings were presented in late October at the Society of Vertebrate Paleontology's annual meeting in Los Angeles.
Up until 2002, all evidence pointed toward scaly reptile-like structures on all dinosaurs. However, evidence emerged in 2002 of the presence of filament-like structures in some ornithischians, leading to speculation that feather-like structures were pretty much common to all dinosaur groups. This theory could now be reversed in light of the new study.
"I'd go so far as to say that all dinosaurs had some sort of genetic trait that made it easy for their skin to sprout filaments, quills, and even feathers," Barrett told Nature. "But with scales so common throughout the family tree, they still look like they are the ancestral condition."
The results are, however, not set in stone, according to Richard Butler, a paleontologist at the University of Birmingham, U.K., because the "picture could quickly change if we start finding early dinosaurs with feathers on them," he said. Further study on this topic could be limited by the fact that we do not have dinosaur remains in the right condition - early Jurassic and late Triassic periods - to study their skin or feather impressions, Butler, who was not associated with the study, told Nature.
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