Re: Evidence For a Feathered Velociraptor...

[ptnorton <ptnorton@suscom-maine.net>]

Tim Williams wrote:

> Turner et al. (2007; Supp Info) make the argument, using Livezey and 
> Zusi's (2007) dataset, that there is a statistically significant 
> correlation between quill knobs and powered flight, despite the absence of 
> quill knobs from certain volant taxa, and the presence of quill knobs in 
> certain flightless taxa.  However, all modern birds are descended from a 
> most recent common ancestor that was flighted (and presumably possessed 
> quill knobs), so it is difficult to extrapolate to non-avians (or maybe 
> even non-ornithurans).

For the sake or argument, I would propose that there *must* be an 
osteological marker (observed or as yet unobserved) for feathers that were 
*selected* to transfer aerodynamic forces to the animal's skeleton. Without 
a firm connection to the skeleton, how else could those forces have acted to 
lift or propel the animal's center of mass? Passive behaviors such as 
brooding, display or thermoregulation do not require this type of 
adaptation, but it seems to me that feather-assisted aerodynamic cursorial 
maneuvering (FAACM; did I just coin that?), powered flapping flight or some 
intermediary form must have required it.

PTJN