Wednesday, January 2, 2013

Feathered Dinosaurs!

Oviraptors, ancestors of birds, had the ability to straighten their plumage.
A new study shows that the ancestors of birds had already developed ornaments of seduction.
It seems that, in the feathered dinosaurs, there were the equivalent of our current peacocks or turkeys. It is in any case the surprising conclusion of a study by two Canadian researchers and one American on tails fossilized several oviraptors ('egg thieves'), the ancestors of birds. Their study is published in the journal Acta Paleontologica Polonica.
The oviraptors were bipedal dinosaurs, herbivores majority, including size, depending on the species, between 70 cm and 8 m they lived between 200 and 65 million years ago, and their fossils were found in China, Mongolia and the Canada. They are often depicted with a crest on the head but all had not. Their tail, shorter than that of other dinosaurs, could contain more than 30 vertebrae. And it is precisely these that Scott Persons, a paleontologist from the University of Alberta, and his colleagues were interested.
First observation, the last tail vertebrae are fused together, as in modern birds, which are the only modern animals to possess this type of bone structure, called peristyle. It helps to form a point of attachment for a range of long feathers. We find this device in the oldest known oviraptors (Similicaudipteryx) which include traces of feathers. And even if no imprint of feathers found in the more recent fossils (up to 45 million years later), the researchers estimate that there are enough clues to think that they should have.
Canadian study
Second observation, the vertebrae of the base of the tail, small and numerous, show that it could be highly mobile, from top to bottom and from right to left, and that she had a helper to terrestrial locomotion function. By comparing this device to rep­tiles and modern birds, the researchers concluded that the tail of the oviraptors should have the same possibility of movement. The second part of the study was to recreate these dinosaur tail muscles. By very sophisticated techniques involving among others of computer software, they were able to reconstruct precisely the size (with volume and mass) and the position of the tail muscles. Result, the oviraptors were able to completely straighten the tip of their tail, and therefore the long feathers that were attached.
A previous Canadian study had already shown that some dinosaurs also had feathers on the forelimbs, which small wings. And had already been hypothesized that this could be an ornament for seduction and mating rituals. Because these feathered dinosaurs could not fly. "With their crest on the head and tail with long feathers, does one feel the oviraptors had a certain propensity to Visual exhibitionism", considers finally Scott Persons.
Shortly before the end of the time of the dinosaurs, 65 million years ago, other species had developed feathers, either to steal, either for a thermal protection. But the love parade of the oviraptors, it must really be something...


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