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RE: WILL THE REAL DEINOCHEIRUS PLEASE STAND UP ?!?



you know what guys .. I'm going to stick my neck way out on this one.
In fact .. I'm going to put it on the chopping block.

Am I the only one looking at ornithomimisaurs from a completely different
perspective here ??

I see these theropods as completely carnivorous .. perhaps .. the most viscious
of all theropods. The following is how I've always seen these critters.

I see them as Nature's answer to ground hugging Mesozoic terrestrial vultures.
These are animals 10 times the size of modern vultures consuming terrestrial
prey .. on average .. 10 times the size of today's African meso-fauna.

I see these animals .. not as prey .. but as viscious scavenger/ hunters.
Their cursorial adaptations were not designed for them to "run away" .. but
rather to "stand their ground" as they competed with other medium and large
theropods gathered around a kill.

Their long necks designed for getting deep inside a carcass. Their long clawed
unguals for scraping flesh from bone. Their long narrow skulls for getting 
between
ribs and possibly other predators.

But there is a problem that ornithomimosaurs faced that modern vultures don't 
today.
Most Mesozoic carcasses did not just have thick hides .. they were strongly 
armoured
[creatopsians/ hadrosaurs/ ankylosaurs/ titanosaur sauropods/ perhaps many 
small 
ornithischians].

On the African veldte .. one particular vulture is specially adapted for 
ripping open
the tough hides of Africa's large herbivorous species. That vulture is the 
"King Vulture".
Now here's a vulture that is crucial to the clean-up commencement of large 
rotting 
carcasses on the African plains. Many other vulture species are absolutely 
reliant on the
specialties of this giant vulture to open large carcasses.

Back to the Mesozoic.

Enter Deinocheirus mirificus .. the "king ornithomimosaur" specially adapted 
for ripping into
armoured carcasses. But wait. A beaked skull could be seriously damaged on such 
prey. So Nature
equiped these deinocheirids with 6 "beaks" .. those nasty clawed unguals. They 
don't have to be
strongly raptorial at all .. just "solid". Break one .. 5 to more to rely 
upon.The forelimbs don't 
have to be very powerful either .. just strong enough to rip open rotting 
multi-ton carcasses.

D. mirificus wasn't an aberant theropod from this particular perspective but a 
crucial link in
a special heirarchy of ornithomimosaurs.

And what about the fluted beak of that Alberta ornithomimosaur ?? Perhaps these 
Mesozoic "vultures"
never needed hooked beaks .. just very sharp fluted ones.

If this is anywhere near the truth then .. mesozoic palaeo art is indeed 
impoverished. Scenes of
scores or even hundreds of theropods battling over a large multi-ton carcass 
may have been the norm.

The cacaphony of such a scene must have been truly deafening by modern 
standards.

There you go folks .. elephantine sized vultures .. or not.

Any comments ??



----------------------------------------
> Date: Thu, 7 Nov 2013 15:40:24 +1100
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: New Deinocheirus specimens found, indicating basal 
> ornithomimosaur
>
> Thomas R. Holtz, Jr. <tholtz@umd.edu> wrote:
>
>> The manual claws of Deinocherius are most definitely NOT raptorial! However, 
>> I understand when just viewing them from a distance
>> they might appear so. Handling the actual specimens (or casts), you find 
>> they are much thicker, much less pointed, and so forth than
>> people commonly think: more like the claws of basal therizinosauroids.
>
>
> I think the reason why the claws of _Deinocheirus_ are so often
> referred to as "raptorial" (such as the chapter on Ornithomimosauria
> in Dinosauria II) is to contrast the claws of _Deinocheirus_ with
> those of other ornithomimosaurs. _Deinocheirus_' unguals are much
> more curved than is typical for ornithomimosaurs (even _Gallimimus_
> and basal forms), with relatively large flexor tubercles that are
> proximally positioned. Ornithomimosaur unguals are distinctly
> non-raptorial (especially in the flat-clawed taxa), with weak and
> distally positioned flexor tubercles. True, the unguals of
> _Deinocheirus_ are fairly blunt and poorly recurved - a long way from
> the highly tapered and recurved unguals with an ovoid cross-section
> seen in undoubted theropod predators. But among ornithomimosaurs, the
> claws of _Deinocheirus_ stand out - and not just for their size.
>
>
> The overall forelimb of _Deinocheirus_ was also more mobile compared
> to other ornithomimosaurs: the humerus could probably be raised much
> higher above the horizontal (no 'supraglenoid buttress') and the
> forerarm was capable of pronation/supination (radius/ulna not
> appressed). So the forelimbs were most likely used for more than just
> the hooking/clamping function inferred for ornithomimosaurs like
> _Struthiomimus_. The hands of _Deinocheirus_ seem more adapted for
> grasping, even if they weren't predatory/raptorial.
>
>
> The hands of _Deinocheirus_ might have been adequate to grasp small
> prey (presumably two-handedly), if it was an omnivore. Or the long,
> curved and fairly blunt claws could have been used to slash or swipe
> attackers, since the aim was not to impale or seize prey, just wound
> an attacker. The smaller and highly cursorial ornithomimosaurs had
> the option of running away from a predator - but _Deinocheirus_, being
> more ponderous and far less cursorial, likely needed another strategy
> to ward off an attacker. That's one hypothesis, anyway.
>
>
>
>
>
>
>
>
> Cheers
>
> Tim