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Re: "carnosaur" classification (was Archaeopteryx Pes)



On Sun, 7 Jan 2001, Ken Kinman wrote:

>       Anyway, that is how a traditionalist (like me) might try to sort
> through this quagmire.  In short, stop the premature splitting of larger
> families, and avoid using the common name "carnosaur" (or a taxon
> "Carnosauria")---- they are about as useless and confusing as "insectivore"
> and "Insectivora".

Only under traditional taxonomy. Under phylogenetic taxonomy, Carnosauria
is Clade (_Allosaurus_ <-- _Passeres_), sister to Coelurosauria
(Clade(_Passeres_ <-- _Allosaurus_)).

"Megalosaurid" seems to be a more useless term to me, at least, as it
stands -- "basal tetanuran"  covers the essential concept better, I think.

> P.S.  QUESTION:  By the way, which has priority, Torvosauridae or
> Megalosauridae?   Is it possible that one could have priority by the
> Zoological Code and the other priority by the PhyloCode???

It is indeed possible, or would be if PhyloCode had been put into effect.
Under ICZN rules, Megalosauridae and Torvosauridae are families, and, if
_Megalosaurus_ and _Torvoasurus_ are to be considered as members of the
same family, Megalosauridae has precedence, since it was named first.

In phylogenetic taxonomy, there are no such things as families, only
clades, and they become available for use once they are defined, not just
once they are named. Megalosauridae has not been phylogenetically defined
(TMK). Sereno defined Torvosauridae as Clade (_Torvosaurus_ <--
_Spinosaurus_), IIRC. So Torvosauridae should get precedence.

Of course, since PhyloCode will not be retroactive, Megalosauridae could
get the nod -- probably as Clade (_Megalosaurus_ <-- _Spinosaurus_,
_Passeres_) or something similar. Actually, not all phylogenies agree that
this is the same clade as Torvosauridae, so they could exist side-by-side.
If they are the same, precedence would be decided by which was registered
with PhyloCode first.

> Nick wrote:
>
> >       Foundation, then structure. Otherwise, we get situations like a
> >Ceratosauria that uses Coelophysis as a reference taxon, so "Ceratosauria"
> >may exclude Ceratosaurus...

PhyloCode has a rule which would prevent situations like this. (Clades
named after genera must include their eponymous genus's type species as an
internal specifier.)

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