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Re: Major new paper on dromaeosaurids, with other significant maniraptoran info



"Tim Williams" <twilliams_alpha@hotmail.com> writes:

>According to Gishlick, the grasping/raking ability primitive
> for the theropod manus was actually lost in the _Deinonychus_ manus.
> Gishlick did describe how maniraptorans could grasp small prey in a
> two-handed 'scooping' fashion; but IMHO this would be inferior to the
method
> that was employed by more primitive theropods - just grabbing the prey
with
> one hand.

In the history of life on Earth, relatively few predators have required
grasping hands with opposable thumbs for catching prey.  Sharp, hooked claws
are usually sufficient to snag or pin mobile food items.  Claws aren't even
required for tripping running animals (as the cheetah does, for example,
without anything approximating grasping).  If groups of _Deinonychus_ did
indeed hunt larger prey -- _Tenontosaurus_, apparently -- it is entirely
possible that these dromaeosaurs were unique in these aspects of their
hunting style.

Certainly dromaeosaurs could have hooked and snatched up small prey in one
hand with ease, or they could have slapped their clawed hands onto small
prey items prior to delivering killing bites.  Most predators today don't
even use their forelimbs to catch their prey, but dromaeosaurs should have
been well enough equipped to use their forelimbs in some fashion in hunting,
even if they didn't have the good sense to go at them with humanoid
forelimbs.

Two handed scooping doesn't sound far fetched to me, as either hand will
snag the intended food item and quickly clap toward the opposing hand before
the animal has a chance to get away.  Dromaeosaurs certainly had long
forelimbs, and I would expect they were good for something (aside from
flying and/or gliding in the smaller varieties).  What aspect of this two
handed scooping scenario troubles you?

--------
"Dino Guy" Ralph W. Miller III
Docent at the California Academy of Sciences
proud member of the Society of Vertebrate Paleontology