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RE: Ceratosauria vs. Neotheropoda?
Tim Williams wrote-
> However, in the wrong hands, paraphyletic groupings could spell big trouble.
> For example, I can foresee the BANDits resurrecting the Thecodontia as a
> paraphyletic group that includes the (alleged) ancestors of birds, and
> claiming the validity of Thecodontia is justified under the rules of
> phylogenetic taxonomy.
> I know Thecodontia is an extreme example; but I can see paraphyletic groups
> being misused and abused by people who (whether by accident or design) equate
> evolutionary 'grades' with clades, and come up with all sorts of spurious
> phylogenetic hypotheses and conclusions as a result.
I'm no fan of BANDits and paraphyletic groups, but I don't see the big worry
here. If they define Thecodontia paraphyletically, it will still indicate a
limited range of taxa that can be used to test phylogenetic hypotheses. The
hypothesis Aves is a clade in Archosauriformes that is outside Crocodylomorpha,
Pterosauria or Dinosauria is just as valid conceptually as the hypothesis Aves
is a clade in Dinosauria. The problem with current uses of the term thecodont
by BANDits is that they have no clear definition of Thecodontia, so include
even such non-archosauriforms as Longisquama and drepanosaurids. If they
define it, problem solved.