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Re: Quo vadis, T. rex? [long]



On Wed, 7 Feb 1996, Jeffrey Martz wrote:

>       Many dinosaur skin impressions are known, perhaps the most 
> spectacular belonging to Carnotaurus and the hadrosaur "mummies".  Except 
> for the peculiar Pelecimimus [sic] "hairs", which are very questionable, 
> no one has ever found feathers on any dinosaur except Archaeopteryx (and 
> post Archaeopteryx birds, if you really want to call them dinosaurs).  

Please define "very questionable" and elaborate on why you think this 
about _Pelecanimimus_'s integument.

Of course birds are dinosaurs.  They have to be, by any definition of the 
term.  If you use a typological definition, birds are dinosaurs because 
they show all the defining typological characteristics of dinosaurs.  If 
you happen to be cladistically inclined, birds are dinosaurs because they 
are descended from the last common ancestor of _Megalosaurus_ and 
_Iguanodon_.


> >    There is very little evidence for arboreal and upland dinosaurs.  Should
> > we therefore conclude that there were no arboreal dinosaurs and no upland
> > dinosaurs, rather than take into account the odds of their fossilization and
> > come to a different conclusion?
> 
>       The absence of an upland dinosaur fossil record is due to a 
> probable bias in the fossil record.  

And there is a *known* bias in the fossil record against feathers!

> Recognizing: 1) the wide geographic 
> range of dinosaurs and 2) the sparsity of fossizing sediments in upland 
> areas, it is reasonable to think the reason there are no upland dinosaur 
> fossils is just that few were being preserved.
> Dinosaur feathers are not the same thing.  There is no more reason to 
> believe that feathers further down the dinosaur evolutionary tree than 
> there is to think they were a trademark of one little twig. 

Dinosaur feathers are exactly the same thing.  Based on the evidence at 
hand, there is very little evidence that dinosaurs lived in upland 
environments.  It is no more and no less absurd to believe that dinosaurs 
lived in upland environments than that they had feathers--there is no 
positive evidence either way!

>      Birds have adapted for flight, something only two other vertebrate 
> groups have ever done.  It is an peculiar and signifigant adaptation that 
> has guided in thier evolution in a unusual direction since the 
> Jurassic. Contary to popular portrayal, T.rex is not just a humungous sparrow.

Of course not.  Sparrows, as passerines, are some of the most derived of 
all birds--entirely unsuitable for comparison with basal birds like 
_Tyrannosaurus_.  No, _T. rex_ was not a humoungous sparrow--it was a 
humongous _Archaeopteryx_.

> LN Jeff
> 

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447
(206)535-8204
PharriNJ@PLU.edu

"If you can't convince them, confuse them." -- Harry S Truman