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

Re: Evidence For a Feathered Velociraptor...

----- 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

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.