Re: Therizinosauria Cladogram

["T. Mike Keesey" <tmk@dinosauricon.com>]

On Sat, 12 Jan 2002, Mickey_Mortimer11 wrote:

> > "Therizinosaurs include six described genera (_Alxasaurus_,
> > _Enigmosaurus_, _Erlikosaurus_, _Nashiungosaurus_ [sic], _Segnosaurus_,
> > and _Therizinosaurus_) of bipedal theropods ... Therezinosaurs [sic] may
> > be described as the aforementioned taxa and all others closer to them than
> > to oviraptorosaurs, ornithomimids, and troodontids."
>
> Ick.  Why oh why must he define it as a stem-based taxon?

Why not? The node (the one anchored on _Alxasaurus_, anyway) is
_Therizinosauroidea_. That stem-based taxon seems a perfectly useful one
to me. I'd think a stem-based definition would be most appropriate ere.

My only real complaint is that it has multiple internal specifiers.

> I think he lists ornithomimosaurs, oviraptorosaurs and troodontids
> because those and therizinosauroids made up his and Dong's
> "Oviraptorosauria" in their 1994 publication.

Probably, but even so, I don't think I have seen any phylogenetic analyses
that would alter the composition of the group under this definition.
Sereno has ornithomimosaurs + alvarezsaurids (his _Ornithomimoidea_) as
their sister group, and everyone else seems to have oviraptorosaurs
(_sensu stricto_) as their sister group.

> Of course, this whole thing started with him and Dong when
> they created Therizinosauroidea.  Their whole discussion of the reasoning
> behind Therizinosauroidea is this (pg.2121)-
> "Therizinosauridae Maleev 1954 is available for a superfamily containing
> Alxasaurus and the Therizinosauridae; the group is referred to below as
> "therizinosauroids"."

What's wrong with this? Even if they had used Segnosauria instead of
_Therizinosauria_, _Therizinosauroidea_ would still be a valid and useful
clade - a node within the stem.

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