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> >Ah, this is important. Assuming for now that this is a valid
> >synapomorphy, not a convergence, it forbids placing Pelecanimimus
> >is a stem group ("Coelurosauria") AND Harpymimus in Ornithomimosauria.
> >[That would make either the "stem" group or the ornithomimosaurs
> >polyphyletic, which no biologist will accept].
> What the hell are you talking about? It does nothing of the sort. A whole
> range of synapomorphies place ornithomimosaurs in Coelurosauria (see
> Gauthier) and additional characters show that Ornithomimosauria is a member
> of the coelurosaurian subgroup Maniraptora (the aforementioned ref. 23).
The difference here is the difference between the stict cladistic
approach to taxonomy and the non-cladistic approach. I treat
Maniraptorea as a taxon that may, or may not, include all of the
descendents of the latest common ancestor of its members.
What I was trying to get at was that if Pelecanimimus is closer
to Ornithomimidae than Harpymimus is, then there are three valid
alternatives, unless one is a cladist:
1) place both Harpymimus and Pelecanimimus in
2) place both in the paraphyletic stem group, whatever
one wishes to call it.
3) place Pelecanimimus all by itself in a more derived
group than Ornithomimosauria; which seems like excessive
splitting to me.
At the time I wrote the above, I was using "Coelurosauria"
as the name of the stem group for the entire nexus under
consideration. However, as it really only includes Compsognathidae,
that is probably a poor choice of name.
After evaluating the new evidence, I am considering a classification
something like the following:
Taxon A (?Coelurosauria)
Stem taxon (?what to name it?)
Caenagnathidae (= Elmisauridae)
Therizinosauridae (= Segnosauridae)
But, I am having a hard time coming up with good names for
some of these groups. Given the way the names are used now,
I suppose Coelurosauria is a usabel name for the largest group,
but I do not really like using it for a group that includes the
dromaeosaurs as the most "typical" members. And the name
Dromaeosauria doesn't seem right for a group containing the
Oviraptorids and Avimimids.
[I am also considering placing Compsognathidae in the subgroup
Maniraptorea, making that the "stem" group, as well as the
core group, of "Coelurosauria"].
> Thus, Pel. & Harpy. are ornithomimosaurs AND maniraptorans AND
Only if you use a strict cladistic classification, *or*
you decide the groups should be defined that inclusively.
> The hand of ornithomimosaurs are thus transformed from the
> basal maniraptoran condition. Given the structure of the hand of
> Harpymimus (which retains a primitively short mc I), it would appear that
> the hand of Pelecanimimus is either convergent with Ornithomimidae, or that
> Harpymimus represents an outgroup to the Ornithomimidae-Pelecanimimus
Quite. If it is convergent, then inclusion of Pelecanimimus
in Ornithomimosauria is not necessary, as it is an "outgroup"
under that situation.
In fact, of the four major subgroups of Theropoda, I am
satisfied with the names of only two (Herrerasauria and
Ceratosauria). I think both of the names "Carnosauria"
and "Coelurosauria" should be retired as formal names.
The peace of God be with you.