Recent studies of archaeopteryx fossils indicate that this famous feathered dinosaur may not have been the direct ancestor of modern birds as previously believed, according to a story in the Wall Street Journal. Growth studies have revealed that archaeopteryx grew at the slow rate common to dinosaurs, rather than faster rates associated with birds, and its adult weight was much heavier than earlier estimates. Comparison with other fossils concludes that the true precursors to birds did not appear until 20 million years after archaeopteryx.There is still debate about which species were the direct ancestors of birds, and where the line should be drawn between when a fossil is a bird or when it is a dinosaur. Other fossils have been discovered in recent years indicating many types of feathered dinosaurs, and studying archaeopteryx and other fossils demonstrates that the theory of evolution connecting birds and dinosaurs is itself still evolving.
Archaeopteryx
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