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Re: "Megapnosaurus" says farewell...

>But, it is still as subjective as grouping rabbits and _Syntarsus_ into the
same genus.<
How is this any different than fossil species? What is the cladistic
definition of a species? Temporal? Morphological? Why not run cladograms
based on individual specimens, as opposed to species, that (at least to me,
the uncladistically-oriented) appear just as arbitrary as a genus, family,
order, etc.

Student of Geology
P.O. Box 20840
Flagstaff, Az. 86011
AIM: TarryAGoat
"A _Coelophysis_ with feathers?"

Convenience, like subjectivity, shouldn't be what guides scientists.
Otherwise, Avogadro's number could be designated as 6.0 x 10^23.
Convenient?  Yes.  Correct?  Only partially.
> ><< I have never quite understood why _Psittacosaurus_ has something like
> >seven or eight valid species, but _Coelophysis_, _Syntarsus_ (Raath),
> >_Eucoelophysis_, etc. were placed in separate genera.  It's aesthetic
> >philosophy, not science sensu stricto. >>
> >
> >So far nobody has been able to come up with a consistent way to group
> >together the various species of Psittacosaurus. You either have x species
> >x genera. They all look enough alike that the species level is considered
> >more appropriate.
> Exactly.  Nobody has been able to subjectively come up with a consistent
way to group the species of _Psittacosaurus_ into anything but one genus.
In this case, as George said, the species level is _considered_ more
appropriate.  However, there is no widely-accepted definition or principle
that merits this.  I think we all know that.
> Regards,
> Steve
> ****
> Steve Brusatte
> Dino Land Paleontology
> http://www.geocities.com/stegob
> ****
> Go Get It!
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