Re: Lewisuchus, a Dinosauriform

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

On Mon, 23 Jul 2001, Ken Kinman wrote:

>
> Mickey,
>      Well, some workers still think herrerasaurs are basal dinosauriforms
> rather than theropods,

But still more advanced than _Pseudolagosuchus_.

> and that even Eoraptor may be more derived than herrerasaurs.

That I have not seen. I've always seen _Eoraptor_ more basal than
_Herrerasauridae_, whether those two taxa are inside _Dinosauria_ or
outside. Who placed _Eoraptor_ "above" _Herrerasauridae_?

> P.S.  I could be wrong, but I don't think it matters if Lagosuchus is a
> nomen dubium.  Family Lagosuchidae could still be the valid family name.

No, it doesn't matter, since it's largely a matter of opinion as to
whether a given name is dubious or not. _Hadrosauridae_, _Titanosauridae_,
and _Ceratopsidae_ are names for genera which are commonly considered
_nomina dubia_.

In a cladistic taxonomy, there would be no reason for a Lagosuchidae,
since _Lagosuchus_ is not known to clade with any other genus. However,
under your system you could make it a paraphyletic group for all
_Dinosauromorpha_ outside Clade(_Eoraptor_ + _Herrerasaurus_ +
_Megalosaurus_ + _Iguanodon_), if you really feel this group needs a name.

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