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



Some other thing... I suppose the knobs are not present in most other
non-coelurosaurian tetanurans. May their presence-absence be related
with the size of the animal? Some kind of regression should be needed.
Concavenator seems to be a relatively small animal.

2010/9/9 Augusto Haro <augustoharo@gmail.com>:
> 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.
>