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Re: humming birds smallest dinosaurs?




Greg Paul wrote:

Remember concerning feathered dinos in JP, that tyrannosaurs had scaly skin
as per fossils. The dromaeosaurs and other small theropods are candidates for
feathers.

Are scales and feathers mutually exclusive? I know modern birds have scaly legs and feet and feathered bodies, but the bodies are naked under all those feathers (as many of us will determine in the not-too-distant future... gobble gobble).


But in the first feathered dinosaurs, did the feathers co-exist with scales over much of the body? Is it a prerequisite (functional, developmental, whatever) for feathers to displace scales? Maybe the feathers sprouted between scales in the first feathery theropods, and scales were 'phased out' in later theropods.

In most modern birds, the body (contour) feathers are arranged in rows or tracts (pterylae) separated by naked skin (apteria). The first feathery theropods probably did not have their feathers arranged in tracts. Some modern birds (paleognaths, penguins, screamers) do not - but whether this is a primitive trait, or arose through secondary loss, or is different for different groups, I know not.



Tim

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