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CRET CROCS AND MAMMALS



> However, although you do see some big (Mesozoically speaking)
> mammals toward the end of the Cretaceous, saying they could have
> been in direct competition with any but the smallest dinosaurs is
> absurd.

(Sorry, I don't know who to attribute this to).  Some might disagree
strongly with this statement. The late Bev Halstead, for example,
argued that small herbivorous mammals would have been numerous enough
and destructive enough to compete effectively with large herbivorous
dinosaurs.  In his famous little 1987 book (with colour plates by
Jenny Halstead), he even worked out that around 1000 herbivorous MTBs
or other mammals would eat as much as one 2 ton hadrosaur - a
population explosion of furballs would therefore mean trouble for the
dinosaurs.

I don't agree, and obviously there are problems. Palaeontologists are
already arguing about the diversity and population sizes of taxa late
in the K - is there a demonstrable relationship between the numbers of
these 2 taxa? Probably not. With extant interactions in mind, it is
very doubtful if any relationship would be so simple. The controversy
that has surrounded growth habit in New Zealand plants and the feeding
habits of moa - an example less than a million years old! - suggests
how tough and open to interpretation such situations can be. And here
we are dealing with a >65 Ma old system where most of the information
is missing and/or unknowable!

CRET CROCS

I recall Nick Pharris' post mentioning body size of late K
crocodilians. I'd be interested to hear size estimates for the
chelonivorous alligatorids (Ken Carpenter?) known from late K
N. America, as well as _Leidyosuchus_. These animals seem smaller than
'typical' modern crocs. While crocodylids and alligatorids (and
dyrosaurids? Pholidosaurids? I need to check the lit) survived,
however, other similar sized amphibious crocs (goniopholids?) didn't.
More evidence of the smart-bomb bolide.

"You cannot hide forever Luke" 
"I will not fight you father"

DARREN NAISH