Re: Suchosaurus, Baryonyx and Martinavis

["T. Michael Keesey" <keesey@gmail.com>]

On 10/2/07, Tim Williams <twilliams_alpha@hotmail.com> wrote:
>
> > I don't see any problem with continuing to use _Baryonyx_,
> > _Troodontidae_, and _Stenonychosaurus_, myself.
>
> I regard any clade based on a nomen dubium (or potential nomen dubium) to be 
> problematic (or ptentially problematic).  This would be the case for 
> Troodontidae if _Troodon_ becomes a nomen dubium.  In that event, 
> Saurornithoididae is available - although it's currently without a definition.

But "dubious" is relative to taxonomic level. For example, it may not
be clear whether the organism represented by the type specimen of
_Troodon formosus_ belongs to the same species as the organism
represented by the type specimen of _Stenonychosaurus inequalis_, so
it could be considered dubious at the "species level". (I'll ignore
for now the problems with the concept of a "species level", especially
in paleontology.) But do they share more recent common ancestry with
each other than with _Dromaeosaurus albertensis_ or _Vultur gryphus_?
Quite likely, yes.

Furthermore, someone correct me if I'm wrong, but I don't think the
ICZN has any official stance on whether a name is "dubious" or not.
(And I know the PhyloCode doesn't.)

In the PhyloCode, as in the rank-based codes, the type specimen(s) of
a genus must be included, by definition, in any eponymous taxon (see
http://www.ohiou.edu/phylocode/art11.html#art11.7). So if Troodontidae
is converted as a clade name, the type specimen of _Troodon formosus_
would have to be included by definition.

> Unless _Suchosaurus_ is a nomen dubium.  Otherwise, you're dead-on.  After 
> all, the Spinosauridae+Torvosauridae clade was originally named 
> Torvosauroidea, but was renamed Spinosauroidea because Spinosauridae was 
> named before Torvosauridae.  This was 'required' by ICZN rules.

Actually, wouldn't the ICZN-required name be "Megalosauroidea"?
(Speaking of potential nomina dubia....)

> At some stage the ICZN and PhyloCode will have to duke it out.  Pistols at 
> ten paces, I say.

Hehe!

> Frankly, I think the best policy would be for ICZN to be restricted to genera 
> and species, and be shorn of any responsibility for coordinated family-level 
> taxa.

That would be a very nice situation. (Although there'd still be some
overlap, since genus-level taxa are open for conversion under the
PhyloCode.) We'll have to see how the PhyloCode does, first, though.

> In the above example, Torvosauroidea was trumped by Spinosauroidea because of 
> ICZN rules; but Torvosauria would have been fine, because as a 
> non-coordinated-family-level taxon it doesn't come up on the ICZN's radar.

A good solution here, but it's not always going to help -- people are
too attached to a lot of "-idae", "-inae", etc. names.

-- 
Mike Keesey