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Re: Concavenator corcovatus, a new humped carcharodontosaurid from Las Hoyas



2010/9/9 Tim Williams <tijawi@yahoo.com>:

> 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

Very interesting idea. The use of the spikes on predation may need the
dinosaur to perform kind of a karate-blow on the bricks with its
antebrachium (although blows are not necessary to stab, perhaps it
would be so if hitting with many spikes). At least for maniraptorans,
if the spikes are also present in the metacarpus, as indicated in
Naish' post, and you have a semilunate carpal permitting some flexion
of the manus on the antebrachium in the same plane in which the
remiges/spikes are located... Can there be some kind of mantis-like
forelimb function in maniraptorans? This may fit with the relatively
larger size of the forelimb in maniraptorans, at least generally.
Enlarged scales are also present along the caudal border of the
extremities also in crocodilians, so the specialization and relatively
larger size of the appendages along that bordermay be some basic
archosaurian design.