[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: semilunate carpal




Tom Hopp wrote:

Having seen the Velociraptor vs Protoceratops fossil (somewhere - maybe at
Dinofest 98?) I'll chime in. The velociraptor was pushing away. I got the
distinct impresson the Velociraptor was in trouble, the fatal variety.
[snip] The animals seemed to me to
have bled to death simultaneously, with a sand storm raging around them.

The two were locked in a fight to the death. But I'd bet pounds to peanuts that _Velociraptor_ started it.



PS I'm not a big fan of the "predatory stroke" hypothesis, having read all of
Ostrom's papers (he started the concept and now disavows it).

I thought Ostrom's hypothesis was rather different: The feathered forelimbs were used as insect nets to bat insect prey toward the mouth. This doesn't constitute a predatory stroke in the sense that it was proposed by Gauthier, Padian and others. Under the latter model, the arms swing forward and downward and the hands actually grasp the prey. The feathers play no direct role in prey acquisition.



As others have
said, if manipulating prey by hand is important, why limit the hand's ability
to adopt various angles and flexions? There is a much more cogent reason for
making a rigid wrist, as I have mentioned before . . .

Yeah, but as I said, manipulation of prey was *not* important. The hands clamped onto the prey and held it tight as the jaws and feet were put to work to subdue the prey (suffocation with the jaws, evisceration or blood loss courtesy of the slashing claws). The _Velociraptor_ and _Protoceratops_ death-struggle is a case in point. The prey is of comparable size to the predator - no manipulation of the prey is necessary. What would be the point of having a hand capable of "various angles and flexions"? The predator just uses its hands to lock on to the prey, the jaws and teeth did the rest.



Tim


---------------------------------------------------------------------

Timothy J. Williams

USDA-ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163



_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp