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Lexovisaurus/Loricatosaurus (was Re: My Sister's New Papers)

> Buffetaut, E., and Morel, N. 2009. A stegosaur vertebra
> (Dinosauria: Ornithischia) from the Callovian (Middle
> Jurassic) of Sarthe, western France. Comptes Rendus Palevol.
> doi: 10.1016/j.crpv.2009.05.001.
> ABSTRACT: A dinosaur vertebra found in the course of road
> works in the âChevain Marlsâ (marine Callovian) of the
> Vermont outlier, near the village of BÃthon (Sarthe,
> Pays-de-la-Loire, western France) is described and referred
> to a stegosaur (cf. Lexovisaurus). [snip]

An interesting nomenclatural issue is raised in this paper.  The authors argue 
that _Lexovisaurus_ is a valid genus, and should have precedence over 
_Loricatosaurus_ as the genus containing _"Stegosaurus" priscus_.  This is 
their reasoning, but I'm not sure I follow...

"In a recent revision, Maidment et al. [22] have
considered that the type material of Lexovisaurus durobrivensis
[18] is undiagnostic and that therefore, Lexovisaurus
is a nomen dubium; they propose a new genus,
Loricatosaurus, to include the specimen originally
described by Nopcsa [24] as Stegosaurus priscus and the
stegosaur skeleton from Argences described by Hoffstetter
and Brun [15,16], Galton et al. [12] and Galton [8].
However, when he erected the genus Lexovisaurus, Hoffstetter
[14] explicitly included âStegosaurus priscusâ
in it (see also Hoffstetter and Brun [16]). In the interest
of the stability of nomenclature, it therefore seems
preferable to continue using the generic name Lexovisaurus,
and to refer to the diagnostic specimens from
the Callovian of England and France as Lexovisaurus
priscus (Nopcsa, 1911) [25] rather than Loricatosaurus
priscus as suggested by Maidment et al. [22]."

I get what they are saying about "nomenclatural stability", and (personally) I 
can see a case for retaining the genus _Lexovisaurus_ as the name for _S. 
priscus_.  But _Omosaurus durobrivensis_ is the type species for 
_Lexovisaurus_, not _S. priscus_.  Unfortunately, _O. durobrivensis_ is 
apparently a nomen dubium, whereas _S. priscus_ is a diagnosable spe
t al. (2008) erected a new genus (_Loricatosaurus_) for _priscus_.

To treat _Lexovisaurus_ as a valid genus (at the expense of _Loricatosaurus_) 
because Hoffstetter (1957) included _S. priscus_ in _Lexovisaurus_, does not 
seem to carry any wait by itself.  I don't have the Hoffstetter (1957) or 
Hoffstetter & Brun (1958) refs, but I do have Galton (1985), who explicitly 
states that _O. durobrivensis_ is the type species for _Lexovisaurus_.  

To do what Buffetaut and Morel (2009) suggest would surely require a decision 
by the ICZN.  It would require that the type species of _Lexovisaurus_ be 
changed from _O. durobrivensis_ to _S. priscus_.  This has happened before for 
other dinosaur genera (e.g., _Iguanodon_, from _anglicus_ to 
_bernissartensis_), and is in the works for _Cetiosaurus_ (from _medius_ to 
_oxoniensis_).  I can see the logic behind retaining _Lexovisaurus_, by having 
the name tied to _priscus_ (instead of _durobrivensis_).  But, as with 
_Iguanodon_ and _Cetiosaurus_, this requires a petition to the ICZN (Article 
81.1 of the Code).  It cannot simply occur "passively" by using the name 
_Lexovisaurus priscus_, and ignoring _durobrivensis_ (the type species).