physiology and dinosaur diversity

["D.W.Naish" <dwn194@soton.ac.uk>]

I guess I'm the only person e-mailing at this time.. is it early morning in the
U.S. or something?

Another word on physiological speculations - the anatomical diversity that
dinosaurs display is NOT good evidence for diversity of physiological
diversification. OK, so dinosaurs may have been physiologically diverse (read
new stuff by Dodson, Chinsamy, Dodson and Chinsamy, Chinsamy and Dodson...) but
this is not reflected by their phylogeny. Yes, dinosaurs are diverse, but they
are all erect limbed, long-limbed creatures with a uniform musculature. Among
mammals, only short limbed, sprawling monotremes have metabolic rates
appreciably different from other mammals. One could equally well argue that the
uniformity of dinosaurs in these regards argues for a uniform physiology: no
dinosaur is a semi-sprawling creature like an echidna. But considering dinosaurs
along with other archosaurs DOES create such anatomical variation - and hence
possible physiological variation too. Too often we just consider dinosaurs as
'equal' to the mammal clade, but I think that it would be better to visualise
dinosaurs as 'placentals', leaving room for archosaurian 'marsupials' and
'monotremes'. (For those mammologist out there, I am not implying that
marsupials or monotremes are in any way inferior to placentals, nor that
placentals are any sort of mammalian pinnacle...)

But, inevitably, I confess that this is all trite (or tripe.. depending on your
point of view). Archosaurs just can't be compared to mammals and now seem to
possess far more flexible physiologies, somewhat regardless of phylogenetic
diversification... and that brings me back to histology..... bored yet?

DINO DAZ THE SCOURGE OF RUSSELLIAN HYPEROPINIONS
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