His claim made Natural Geographic review their research and they too came to the same conclusion. Comparing the photograph of the specimen with another find, Chinese paleontologist Xu Xing came to the conclusion that it was composed of two portions of different animals. In 1999 a supposed 'missing link' fossil of an apparently feathered dinosaur named " Archaeoraptor liaoningensis", found in Liaoning Province, northeastern China, turned out to be a fake. Actually they have roughly the same appearance as those of birds fossilized in the same locality, so there is no serious reason to think they are of different nature moreover, no non-theropod fossil from the same site shows such an artifact, but sometimes show unambiguous hair (some mammals) or scales (some reptiles). There had been claims that the supposed feathers of the Chinese fossils were a preservation artifact. The most important discoveries at Liaoning have been a host of spectacular feathered dinosaur fossils, with a steady stream of new finds filling in the picture of the dinosaur-bird connection and adding more to theories of the evolutionary development of feathers and flight. The area was teeming with life, with millions of leaves, the oldest known angiosperms, insects, fish, frogs, salamanders, mammals, turtles, lizards and crocodilians having been discovered, to date. The fine-grained ash preserved the living organisms, that it buried, in extraordinary detail. The area had repeatedly been smothered in volcanic ash produced by eruptions in Inner Mongolia, 124 million years ago, during the Early Cretaceous Period. The fossils were preserved in a Lagerstätte - a sedimentary deposit exhibiting remarkable richness and completeness in its fossils - in Liaoning, China. Olson, disputed the links, citing the lack of fossil evidence for feathered dinosaurs.Īfter a century of hypotheses without hard evidence, beautifully preserved (and legitimate) fossils of feathered dinosaurs were discovered, during the 1990s and 2000s. Some mainstream ornithologists including Smithsonian Institute curator Storrs L. Some dinosaur restorations began to picture dinosaurs with a downy or feathery cover.ĭirect evidence to support the theory was missing, however. In all, over a hundred distinct anatomical features are shared by birds and theropod dinosaurs.īy the 1990s, most paleontologists considered birds to be surviving dinosaurs and referred to 'non-avian dinosaurs' (those that went extinct), to distinguish them from birds ( aves or avian dinosaurs). Skeletal similarities include the neck, the pubis, the wrists (semi-lunate carpal), the ' arms' and pectoral girdle, the shoulder blade, the clavicle and the breast bone. Further comparisons of bird and dinosaur skeletons, as well as cladistic analysis strengthened the case for the link, particularly for a branch of theropods called maniraptors. Ostrom has since become a leading proponent of the theory that birds are direct descendants of dinosaurs. Then, in 1964, John Ostrom discovered a fossilized dinosaur he called Deinonychus antirrhopus, a theropod whose skeletal resemblance to birds seemed unmistakable. For the next century, claims that birds were dinosaur descendants faded, with more popular bird-ancestry hypotheses including 'crocodylomorph' and ' thecodont"'ancestors, rather than dinosaurs or other archosaurs. The leading dinosaur expert of the time, Richard Owen, disagreed, claiming Archaeopteryx as the first bird outside dinosaur lineage. In 1868 he published On the Animals which are Most Nearly Intermediate between Birds and Reptiles, making the case. He cited skeletal similarities, particularly among some saurischian dinosaurs, fossils of the 'first bird' Archaeopteryx and modern birds. Shortly after the 1859 publication of Charles Darwin's The Origin of Species, British biologist and evolution-defender Thomas Henry Huxley proposed that birds were descendants of dinosaurs. 4 Taxonomy and the inference of feathers in other dinosaurs.
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