Re: humming birds smallest dinosaurs?

["Tim Williams" <twilliams_alpha@hotmail.com>]

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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