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What with exams and other such nonsense, I haven't been able to comment on some
recent dino-list issues that have caught my attention. Whatever, in regard to
the validity of Cope's Rule, Ron Orenstein said..
> (though there might have been some
> reversals along the way - at least some of the modern mammalian megafauna
> may (I think?) have recent ancestors that were larger than their modern
Most extant mammalian megafauna have larger Pleistocene relatives or ancestors.
As a consequence, you will find the Pleistocene described as a time of
'giantism'/'gigantism' in many texts. In fact, our concept of giantism vs.
dwarfism is misplaced by bias in this case: it seems instead that the modern
mammalian megafauna consists of *dwarfed* members (rather than the Pleistocene
representatives being giants). This is causally related to late Pleistocene
changing climatic conditions with a decimation of local biotypes: see paper by
Guthrie in _Ice Age Extinctions: The Search for a Cause_ for a very thorough
overview. Guthrie's book _Frozen Fauna of the Mammoth Steppe_ discusses the
whole Pleistocene shebang and all of its effects on megafauna.
Resolution of the Pleistocene-Recent mammalian record is excellent, far better
than anything from the Mesozoic - for obvious reasons (evidence not left out 'in
the rain' for so long, for one). It therefore provides a very important insight
into macrofaunal turnovers, patterns of diversity and extinction, and ecological
interplay amongst animal and plant taxa. It is indeed a conspicuous fact that
just about all of the workers that have looked at large scale Mesozoic ecology
are also frighteningly well versed in Pleistocene palaeontology (yes, even
Bakker.. I'll puke if I see him thanked in the acks of yet another Pleistocene
mammalogy paper). I was delighted to learn that our own Jim Farlow, the most
respected of all dinosaur palaeobiologists, has done quite a bit of stuff on a
variety of Pleistocene mammals. So don't have a go at me next time I talk about
mammoths or sabre-tooth cats..
Not that I will of course.
"Oh well, some things never change"
"Oh well.. some things.. never change.. smarck smarck!!"
"The only constant is change"