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Re: Vestigial Arms (was: Theropod limbs - how mobile?)



Mike Skrepnick wrote: *** The more solidly built / less articulations built into the grasping organ, the more efficiently it is able to complete its function.  (snip!)
 
Okay, I'm slowly getting a picture here. This isn't grasping the way I normally think of grasping (opposable thumb etc), it's more like a pair of pliers or mole-grips.  Does the immobility of the hand and it's size tell us anything about the prey it was going after then?
Seems to me our poor, much abused cat would be better grasped with a smaller, bendier hand whereas the dienonychus' manus would be better suited to larger prey?
Also, is it possible to tell if these adaptations were evolved for prey capture or if they were later exaptions (is that the right word?) from Archie-type wings?
 
David Marjanovic wrote: . As I cited, "As with most extant predators, the mouth was used to grasp the prey. Then the short, powerful arms were used to grasp or clutch the prey against the body to prevent its escape while the teeth were disengaged and repeated bites made to kill the prey."
 
Sorry if I seem to be labouring this point, but I'm still having trouble with it. While I'm not disputing that it is physically possible, why is it better to do this rather than deliver a big bite and back off? As I understand it, theropods can't take falls and knocks the way for example big cats can. So why risk grappling with prey about as heavy as they were?
 
thanks
Michael