Re: Extinction

["Larry Febo" <larryf@capital.net>]

-----Original Message-----
From: John Bois <jbois@umd5.umd.edu>
To: Dinogeorge@aol.com <Dinogeorge@aol.com>
Cc: majestic_cheese@yahoo.com <majestic_cheese@yahoo.com>; dinosaur@usc.edu
<dinosaur@usc.edu>
Date: Thursday, March 23, 2000 1:01 PM
Subject: Re: Extinction


(snipped)


>For example, the lack of reconvergence to
>very large body size in egg layers during the Cenozoic is a very
>interesting fact; and it may have a bearing on the patterns of survival
>and extinction at the K/T.

(and snipped again)

What do you consider as large??? I think some of those "large"
phorusrhachids were rather big. How about those later elephant birds (now
where did they get that name???). Even ostritches seem rather huge (in my
opinion). Sure, they weren`t as large as perhaps tyrannosaurs, or even
allosaurs. Perhaps the large size of these theropods IS related to the size
of the prey. Dinosaurian herbiviores perhaps got so huge, because they had a
more efficient "avian" type respiratory system, that allowed a larger mass
to be cooled off to tolerable temperatures. Mammalian herbiviores, not
having this feature, could only get so large (whales aside). Hence their
avian predators (assuming those larger phorusrachids were meat eaters), only
had to get large enough to handle their prey......perhaps.