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Re: Clarifications of Paul's new DA taxa
Greg Paul wrote-
> This means that A&C names in practical terms are never ever synonymous
> any clade node taxa. Avepoda can never be the equivalent of Neotheropoda,
> Eutheropoda or anything else.
True, they can never be exact synonyms when we take the poor fossil record
into account. But they can be effective synonyms of node-based taxa if we
fail to find taxa outside the node that lack the apomorphy. If
Maniraptoriformes and Avepectora end up containing the exact same set of
discovered taxa, they will become effective synonyms and the latter might
not be used for priority reasons for example. This is what I meant by
saying they could become junior synonyms with previously named taxa.
Avepectora would still be a real clade, but discussing a clade containing
maniraptoriformes and the hypothetical undiscovered taxa directly basal to
it might not have much utility.
> Currently Averostra includes ceratosaurs (which I and other consider not
> allied with coelophysoids) and the rest of avepods closer to birds.
> Dilophosaurus appears to be a coelophysoid that evolved a promaxillary
> fenestra independently of averostrans, so it is an averostran mimic. In
> less likely event that that Dilophosaurus is closer to the ceratosaur-bird
> clade than coelophysids then it is an averostran. Or, in the unlikely
> that the Ceratosauria is a monophyletic clade then both ceratosaurs and
> dilophosaurs are probably not averostrans, unless coelophysoids lost the
> extra fenestra. Again, averostra is not the junior synonym of any clade
Do you still believe that Dilophosaurus is nested in the Coelophysoidea
(with Liliensternus closer to it than either are to Coelophysis for
example), or do you agree with some recent work suggesting it's the basal
member of the clade? If the latter is true, it's ambiguous whether
coelophysids are primarily or secondarily non-averostran, so Averostra could
be equally well placed near Avepoda or Neotheropoda. This ambiguity
regarding where to apply the name would make Averostra less preferable than
either Avepoda or Neotheropoda in that situation.