Re: Evidence For a Feathered Velociraptor...

[David Marjanovic <david.marjanovic@gmx.at>]

----- Original Message ----- 
From: "Tim Williams" <twilliams_alpha@hotmail.com>
Sent: Tuesday, September 25, 2007 4:32 AM

> > It's also not clear that the very limited range of motion in the
> > maniraptoran manus was used for holding the struggling prey at all; the
> > proto-flight-stroke looks more like a mechanism for slashing something
> > apart.
>
> That's a cool idea.  Has it been looked at in detail (biomechanics, etc)?

Actually, yes. There's a chapter in, IIRC, Mesozoic Vertebrate Life which 
investigates the biomechanics of various theropod forelimbs. On the one end 
of the range the authors find *Tyrannosaurus*, followed by *Allosaurus*: all 
speed sacrificed for power -- short, massive, columnar bones, small range of 
motion at each joint, distal muscle attachments (in part accomplished by 
shortening the bones). On the other they find the birds (an eagle was used), 
followed by *Deinonychus*: all power sacrificed for speed -- long, gracile 
bones, large ranges of motion, proximal muscle attachments.

BTW, humans are in the middle: a compromise between speed and power, plus 
ludicrously large ranges of motion -- half of speed and half of power 
sacrificed for mobility.

----- Original Message -----
From: "Richard W. Travsky" <rtravsky@uwyo.edu>
Sent: Tuesday, September 25, 2007 5:43 AM

> On Mon, 24 Sep 2007, Nick Page wrote:
> > I thought car spoilers mainly worked by giving a downward force and 
> > increased
> > traction to the drive wheels.
>
> Apparently works both ways; a surprise to some drivers as evidenced by
> those comments below ;)

What comes below shows that there's only a downward force, the way I read 
it.