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

Mammals as cause for K/T extinction.



Claim: All late-Cretaceous mammals were small (shrew-size),
insectivorous, and insignificant.
Fact: Mammal teeth were rapidly diversifying before K/T.  Omnivorous, and
likely carnivorous forms are known.  One marsupial was the size of modern
Virginia possum.  But it had teeth like a sea otter and could crack clams
if it wanted.  It could also crack dinosaur eggs.  Gape is not an issue.
Rats eat croc eggs.  Jackals (small) break ostrich eggs by rolling them
into
each other (their shells are thicker than many non-avian eggs).  Voles
gnaw deer antlers.
Another relatively common late C. mammal was the placental Cimolestes
magnus.  This was a likely ancestor of Carnivora and was capable of
carnivory and, like many/most carnivores today, likely capable of eating
eggs too.  It was the size of a badger.  
We know a fraction of the real diversity.  How big that fraction is, is
anyone's guess.  Archibald's protoungulate find demonstrates that the
modern orders were probably radiating before the K/T according Novacek.
Molecular clock evidence agrees. This is evidence!!!!  
Also, why ignore the radiation of birds?
For the first time in the history of the Earth, almost all the flying
creatures possessed beaks.  This was a major takeover of an important
niche.  As another post said, birds are fantastic egg predators today.

I won't go on, except to say the diversification of mammals and birds
comprised a major confluence of novel speciation just at the time
non-avian dinosaurs were becoming extinct.  The extant ancestors of these
species, creatures of comparable size and morphologies, are today
responsible for suppressing the evolution of large-bodied oviparous
species.  An inference of causality is justified, or at least worthy of
study.

Finally, I don't know the author of the original post and have paid him no
money.