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Re: [Re: Reptilia]



In a message dated 12/10/98 4:11:43 AM Eastern Standard Time,
qilongia@yahoo.com writes:

<<  John Jackson, not so long ago, said that there are no characters
 that are not function related. Every aspect of our biology evolved to
 do _something_. >>

No disrespect, but I read a long while ago that some mutations are neutral and
continue as 'passengers'.  They may eventually find a use or they may not.

I've been reading The Compleat Cladist with the previous discussion in mind,
and I still can't escape the logic:
1.  characteristics are used to define the ancestral animal
2.  the ancestral animal defines the group
3.  therefore, characteristics define the group.
(I know character is used rather than characteristic, but usually a character
is an i or a 2 or an &, so I hope this is generally clearer.)

When you said:
  The definition is "all taxa closer to *Oviraptor* than Neornithes".
Since by various analyses (Gauthier, Gauthier and Rowe, Holtz) have
produced data which show dromaeosaurids (and Archie) are
Oviraptorosauria's closest outgroup, this can be shown that any animal
with a closer morphological similarity to ovis than dromies (after
first dismissing the rest of Theropoda as possibilities) must be an
oviraptorosaurian. 
sounds like you're working with a characteristics-based relative definition.

The Compleat Cladist is very interesting, though I would wish they'd use more
examples when introducing concepts, so I'd have fewer salmon-swimming-upstream
feelings.