RE: Evidence For a Feathered Velociraptor...

[Tim Williams <twilliams_alpha@hotmail.com>]

Mickey Mortimer wrote:


> Penguins no longer have remiges, but still have quill knobs. 


The situation regarding quill knobs is apparently a little complicated in 
penguins.  Some penguins have 'pits' rather than knobs 
along the ulna.  So do the extinct plotopterids, apparently.  Says Mayr (2004; 
p. 63)...


"A highly characteristic derived peculiarity of the ulna of plotopterids is the 
presence of a row of marked pits for the attachment 
of feather quills (Olson 1980, Fig. 3; Olson and Hasegawa 1996, Fig. 6D). Olson 
(1980, p. 55) considered this to be 'a unique 
condition in birds, and quite unlike that in penguins in which the remiges can 
no longer be differentiated from other feathers of 
the wing'.  However, a similar row of pits, although less marked, is found in 
some modern penguins (_Eudyptes_, _Eudyptula_, 
Fig. 3)."


> Dodos are flightless but have quill knobs. Kagus are almost flightless, but 
> have large quill knobs. The largest knobs are 
> present in roadrunners and go-away birds. 


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).



Cheers


Tim
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