Re: Dinosaurian Class (was: DROMAEOSAURS AND OVIRAPTOROSAURS ....)

[tonyc@foe.co.uk (Tony Canning)]

> From owner-dinosaur@usc.edu Tue Jun 16 23:24 BST 1998
> Date: Tue, 16 Jun 1998 17:22:53 -0500
> From: David Hill <daveyohill@earthlink.net>
> To: Dinolist post <dinosaur@usc.edu>
> Subject: Re: Dinosaurian Class (was: DROMAEOSAURS AND OVIRAPTOROSAURS ....)
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> Dear RKC
> 
> I do believe that you posess most of the facts however, I don't think it's
> fare to classify endothermic animals with ectotherms.  I assume that you're
> familiar with the protomammals of yore?

Science isn't designed to be fair, but accurate, informative, testable
and falsifiable

>       Gorgonopsians and other protomammals gave uprise to the mammals we
> know today but they are considered reptilian,

No, they're not

 >does this mean I'm a reptile?

No

> We might as well throw everything back into the mix by saying that birds
> are reptiles.  I'm merely saying that we musn't abolish all the bounderys
> which give us diversity.  I agree with you on many points, But I still
> think that we need to have strick determining factors of which one would
> use to classify an animal.
> I think the difference of endothermy and ectothermy should not be excluded.

Endothermy can, and does, arise independently in groups which are not closely
related.  This makes it an unreliable character.  Also, as metabolic status
cannot be determined from fossils (in some cases it may be inferred, but
this is controversial) on pragmatic grounds alone it is not a useful
taxonomic character.


>       The basic rules that you are using have holes in them.  Lizards
> look alot like salamanders so that means reptiles are amphibians! Early
> amphibians look like lungfish, therefore amphibians are fish.  You see, it
> just keeps going!  We need stricter guidelines.
> 

The rules of cladistics have nothing to do with superficial resemblance -
I don't see what your point is here?

> Sincerely
> NDH
> 
> P.S. I respect your oppinion and I thank you for being more polite than
> some other listers (including myself).
> 

Hope I don't sound impolite! 

Tony
tonyc@foe.co.uk