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sexta-feira, 4 de novembro de 2011

To be or not to be a bird

Nature 479,8 (03 November 2011) doi:10.1038/479008a
Published online
The winged creature Archaeopteryx, which lived about 150 million years ago, may be back on its perch as the first known bird. This long-held designation was challenged by a study that examined the morphology of and relationships between dozens of bird and dinosaur fossils (Nature 475, 465470; 2011). It concluded that Archaeopteryx (fossil pictured) was more closely related to dinosaurs such as Velociraptor than to early birds.
Michael Lee at the South Australian Museum in Adelaide and Trevor Worthy at the University of New South Wales in Sydney, Australia, have reanalysed these data with methods that are often used to draw evolutionary relationships from genetic information. Their work groups Archaeopteryx closest to birds, making it distinct from feathered and other related dinosaurs. However, because transitional forms between birds and dinosaurs differ very subtly, future fossil discoveries could reshuffle Archaeopteryx's relationship with birds and dinosaurs yet again, the authors say.
L. PSIHOYOS/CORBIS
Biol. Lett. 10.1098/rsbl.2011.0884 (2011)

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