Archaeopteryx, supposedly the oldest and most primitive Bird on Earth, would not have been a bird after all, say scientists.
The controversial assertion, if confirmed, is something of a pump for researchers, who have seen the evolution of birds and feathers for flight through the lens of the species that was discovered 150 years ago.
The finding leaves to explain the history of birdlife paleontologists in the uncomfortable position of having to identify another creature as the oldest and original avian.
Archaeopteryx was discovered in 1861, two years after Charles Darwin published the origin of species. Spectacular fossils of an animal with wings with feathers of birds, but the teeth and tail of a dinosaur, caused an immediate sensation in England where the society was dealing with the consequences of evolution through natural selection.
Although the descriptions of archaeopteryx as a "missing link" are widely failed by the scientists, the creature became a renowned as the bird more primitive planet.
Now, this view has been challenged by researchers in China who have tried to topple the fossil with feathers on his perch in a reassessment of family tree dinosaur bird.
XING Xu in Linyi University and colleagues ran the fresh analysis after studying a new fossil archaeopteryx as purchased at a dealer of the Shandong Tianyu Museum of nature, the world's largest dinosaur museum. The fossil was probably excavated from the 155 million years ago the Tiaojishan formation in Eastern China. The size of chicken creature called Xiaotingia zhengi in honor of the scientist who established the Museum as a repository of vertebrate fossils, shares several characteristics with archaeopteryx, including resistant and long arms which presumably allow him to fly.
But when the team rebuilt Xu family trees to include Xiaotingia, they found the creature belonged not in the lineage of birds, but a group of dinosaurs called deinonicosaurios. Most notably, archaeopteryx appeared in the same group, according to the study in nature. Deinonicosaurios, like velociraptor walked on two legs, ate meat and had vicious retractable claws. The finding is temporary, but is based on the doubts that have arisen on the special status of archaeopteryx after the discovery of other dinosaurs from birds and dinosaurs during the last decade.
In an article that accompanies it, Lawrence Witmer of Ohio University wrote: "there has been growing concern about the situation bird archaeopteryx, one by one, their attributes 'bird' (feathers, arm and hand with three fingers) began to appear in dinosaurs." "Perhaps now the time to finally accept that Archaeopteryx was a small theropod with feather bird fluttering around in the early Jurassic."
If archaeopteryx was a dinosaur, it means flight evolved at least four times in vertebrates: reptiles, birds, dinosaurs and more recently in bats.
Witmer adds that dethroned archaeopteryx, most recently discovered fossils, including epidexipteryx, Jeholornis and sapeornis, become candidates for the world's oldest bird. In a note of warning, add the following fossils unearthed in China easily feathered could recover the main condition of archaeopteryx.
Paul Barrett, a researcher of dinosaurs at the Museum of Natural history in London, said: "the overall picture of the descendants of the dinosaurs eat meat of birds is now very firmly established." This is an argument in a relatively small reorganization of some of the branches in the evolutionary tree close to the origin of birds. Does not affect a large part of our panorama view of how the birds came from dinosaurs, but some of the details: small changes that are important to the biology of animals.
"This part of the evolutionary tree is very sensitive to small changes in the way we interpret the anatomy and the combination of anatomical features that we see in these animals are discovered." As a result, the structure of the evolutionary tree is very unstable and can turn around. "Archaeopteryx was perhaps not in the direct line of ancestral to birds, but it was part of an early experiment in the creation of a bird body."
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