Re: Armadillos at the K/T!

["David.Marjanovic" <David.Marjanovic@gmx.at>]

----- Original Message -----
From: "Michael Bruce Habib" <mbh3q@cms.mail.virginia.edu>
Sent: Thursday, October 04, 2001 1:15 AM
Subject: Re: Armadillos at the K/T!


> The fact that there are no dinosaur decendents larger than
> an ostrich may simply mean that the selective advantage
> associated with that increase in size does not exist at
> this time.  The mere existence of a niche does not mean
> there is a selective advantage to occupying it.

Usually there is a selective advantage in entering an empty niche -- the
absence of competition there. Of course that doesn't mean that the necessary
mutations will automatically happen. The time available for such mutations
may be a factor. Maybe that's the reason why no known neornithine, not even
a moa on mammal-free NZ, ever got bigger than *Bullockornis* which is, for a
dinosaur, not big.