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Re: Quo vadis, T. rex? [long]
On Wed, 7 Feb 1996, Jeffrey Martz wrote:
> The gaps in the fossil records create all sorts of uncertainty
> regarding classification, the reason that there is so much disagreement
> on this list as far as what goes into what. We base our classification
> on what is KNOWN. It is POSSIBLE that there were
> tyrannosaurs with dromeosaur style toe claws. However, considering the fact
> that no such fossil has been found, no one has sunk the dromeosaurs into the
> tyrannosauridae. Feathers and adaptations for flight are known to be
> associated with the bird lineage, so for the time being the best option
> for the time being is to remove them.
The two scenarios you outline above are not parallel. Tyrannosaurs and
dromaeosaurs are rather different critters (more scientifc jargon). Toe
claws are not the only things keeping dromaeosaurs out of the
tyrannosauridae. The two taxa are also roughly coordinate. Birds are a
*subset* of dinosaurs, barred only by their flight adaptations from being
universally considered such.
The same argument could just as easily be
used to separate bats or whales from the rest of the Mammalia, if all
terrestrial mammals were to die off and all we had were their fossils.
Yet that is not the way we classify them. Bats and whales are merely
two examples of the broad spectrum of mammalian adaptation, just as birds
are merely an example of the broad spectrum of dinosaurian adaptation.
Whales, moreover, are also mesaxonians, ungulates, and eutherians, just
as birds are also maniraptorans, coelurosaurs, tetanurans, and theropods.
> LN Jeff
Pacific Lutheran University
Tacoma, WA 98447
"If you can't convince them, confuse them." -- Harry S. Truman