“Dinosaur feathers” are all over the news again, thanks to a paper in Science revealing feathers in amber found in Canada. But whose feathers are they? Inferences from other sources, not from the amber, were brought into the interpretation, even though the discoverers admitted, “There is currently no way to refer the feathers in amber with certainty to either birds or the rare small theropods from the area.” And modern-looking feathers of diving birds like grebes were also found in the same amber, leading to numerous questions about what can rightly be inferred from the fossils themselves. No matter; most of the media loved the evolutionary implications and trotted out their headlines that feather evolution from dinosaur to bird has been proven.
McKeller, Chatterton, Wolfe and Currie combed through 4000 amber samples in two Canadian museums taken from around Grassy Lake, Alberta. The strata are said to be late Cretaceous and dated at 80 million years old, way into the period in the evolutionary timeline when birds already were flying like modern birds. The amber samples were already well known for their diverse insect inclusions, but for the first time, feathers were found, in a variety of forms.
“Although amber offers unparalleled preservation of feathers, only isolated specimens of uncertain affinity have been reported from the Late Cretaceous,” the authors began their paper in Science.1 “This contrasts with the rich Early Cretaceous compression assemblage from northeastern China leaving a substantial temporal gap in our understanding of feather evolution,” to say nothing of a geographical gap (the only other alleged dinosaur-to-bird “transitional form” being Archaeopteryx from Germany – but see 7/21/2011 and PhysOrg reinterpretation and new questions). Considering these two substantial gaps, how could the authors claim they were watching feather evolution in action, from dinosaur to bird?
For one thing, they found a variety of feathers and feather parts that they fit into the “currently accepted evolutionary-developmental model for feathers.” Evolution was, therefore, assumed from the outset. They found single filaments (stage I in the model), tufts (stage II), simple feathers (stage III), barbed feathers (stage IV), and advanced veined feathers (stage V) suitable for flight or for diving (as found in grebes). It didn’t bother them that all of these stages can also be found on modern birds, or can represent degenerate structures from modern feathers in fossils….
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