"Jura" <pristichampsus@yahoo.com> wrote:
Sad, it really just reads like the authors want these
to be quill knobs more than anything else. Maybe the actual
paper offers better insight.
Hmmm... I really don't see why the idea of quill knobs in a
carcharodontosaur is so controversial. We already know that
_Velociraptor_ had them. _Velociraptor_ couldn't fly, and there's no
compelling evidence that it evolved from flighted ancestors. So
_Velociraptor_ tells us that the presence of quill knobs cannot be
assumed to indicate flight ability. _Concavenator_ tells us that quill
knobs can exist in non-maniraptorans.
One possibility is that the quill knobs anchored spike-like
integumentary structures along the ulna in _Concavenator_ and
_Velociraptor_. These spikes may have therefore been quite widespread
among theropods, but did not always leave an osteological 'footprint' (=
quill knobs).
This isn't my idea, but comes from Darren Naish over 10 years ago:
"Another thought it that some non-avian theropods could have modified
their primaries into stiff, spike-like structures that could not have
been fouled or snapped in predatory strikes."
http://dml.cmnh.org/1999Feb/msg00470.html