Re: Class-less dinosaurs

[Phillip Bigelow <n8010095@henson.cc.wwu.edu>]

chartiem@ere.umontreal.ca (Chartier Michel) wrote: 

>       I don't think that the desire to retain the class Aves has much
>to do with what you think is their proper phylogeny (i.e. be they 
>descended from dinosaurs, crocodiles or whatever) as much as it has to do
>with what kind of systematist you are, i.e. pheneticist (numerical
>taxonomist), evolutionary systematist (evolutionary taxonomist), or
>cladist (phylogenetic systematist).
 a good discussion of the differences in the various classification 
philosophies snipped... 

>Michel Chartier
>Departement d'anthropologie
>Universite de Montreal

  Michel Chartier addressed all of the main points of the Aves-as-a-Class
vs. Aves-as-something-else issue, plus a few others I hadn't thought about 
(such as what do we do with the archosaur clade).
  I think what instigated my post was the question of how the disciplines of
phylogeny, systematics, Henning cladistics, and traditional Linnaean
classification must appear to the average non-scientist.  It must appear to
be a muddled mess!  It probably is a muddled mess to scientists,
too.

Putting dinosaurs into their own Class seems to be a less inflamatory issue
than is moving birds out of Class Aves.  One reason for this could be the 
rigidity of classical Linnaean systematics. One question that needs 
to be asked is whether the Linnaean system was constructed
with the provision that it could be ammended?  It appears, to me, at least,
that Linnaean systematics is not easily ammendable, at least compared to
cladistics.

Since birds are significantly derived relative to other 
theropods, are they, _comparatively_ speaking, more derived from
theropods than are ornithischians from theropods?  In other words, if 
ornithischians are relatively more divergent from theropods, but are still
called "dinosaurs", then there is a double standard that is being applied to
birds.  From what I gather, birds are structurally closer to advanced theropods 
than advanced theropod dinosaurs are to ornithischians.  A double standard. 
  Further, it seems strange to have a systematic Class crammed inside another
systematic Class.  Not only is it counterintuitive, but it appears to be
flat wrong. 

Even if traditional Linnean systematics is used (ignoring
cladistics all together) it still looks like birds belong in Class DINOSAURIA.
I would be interested in what Tom has to say about the whole mess.