RE: Suchosaurus, Baryonyx and Martinavis

[Guy Leahy <xrciseguy@sbcglobal.net>]

--- Tim Williams <twilliams_alpha@hotmail.com> wrote:

> 
> 
> Denver Fowler wrote:
> 
> > Some of this is being discussed on my SVP poster
> (rather unfortunate that buffetaut's paper comes out
> right before my
> 
> > presentation), but I think Buffetaut is looking
> for an excuse to keep Baryonyx, rather than really
> coming up with a good
> 
> > defensible reason not to dump the genus for
> Suchosaurus:
> 
> 
> 
> Yes, that was my impression too.  It's a nice way to
> avoid controversy, since sinking _Baryonyx_ into
> _Suchosaurus_ would be a BIG deal.  _Suchosaurus_
> was 
> sacrificed on the altar of nomenclatural stability. 
> On that point...
> 
> 
> 
> > The good examples of troodon and
> carcharodontosaurus (mentioned by tim) are identical
> cases.
> 
> 
> 
> In both cases (_Troodon_ and _Carcharodontosaurus_)
> the names might benefit from nominating a neotype,
> as was done for _Iguanodon_.  Otherwise, I can see 
> somewhere down the track both genera (_Troodon_ and
> _Carcharodontosaurus_) being declared nomina dubia
> on account of them been founded upon isolated 
> teeth.  Of course, the alternative is to throw both
> genera (_Troodon_ and _Carcharodontosaurus_) to the
> wolves, as has been done for so many other
> tooth-based 
> taxa  (_Trachodon_, _Deinodon_, and now
> _Suchosaurus_).  As Denver is alluding to, this
> business of determining seniority is so very
> arbitrary and subjective.  
> _Troodon_ trumps _Stenonychosaurus_, but _Baryonyx_
> trumps _Suchosaurus_, even though they're completely
> analogous situations.
> 
> 
> The added complication is that both _Troodon_,
> _Carcharodontosaurus_ and _Baryonyx_ are all
> nominative genera for established higher-level taxa
> (Troodontidae, 
> Carcharodontosauridae, Baryonychinae).  Then again,
> Ceratopsidae continues to be used, even though
> _Ceratops_ is almost always regarded as a nomen
> dubium.  
> More airy-fairy, hand-wavey justifications, rather
> than hard-and-fast objective rules.
> 
> 
> > Baryonyx is a junior synonym of Suchosaurus.
> Nevertheless, Baryonyx is a nicer name than
> Suchosaurus, although
> > Suchosaurus is more descriptive... I suppose you
> could argue that Bary is in more general usage...
> but then collectors
> > on the Isle of Wight, UK, were using the term
> Suchosaurus for baryonychid teeth, long before
> Baryonyx itself was even
> > named. Furthermore, at the very least, if
> Suchosaurus can indeed be attributed to
> Baryonychidae/Baryonychinae-
> > Spinosauridae (which it can).. then the
> nomenclature should recognise it as the senior
> taxon, thus
> > Spinosauridae=Suchosauridae,
> Baryonychinae=Suchosaurinae etc. which I think is
> much better.
> 
> 
> 
> The added benefit is that Spinosauridae is founded
> upon _Spinosaurus_, and it has been suggested that
> _Spinosaurus aegyptiacus_ is a composite taxon 
> (spinosauroid jaws+teeth, carnosaurian dorsal
> vertebrae).  By sinking Spinosauridae (as well as
> Baryonychidae) into Suchosauridae, we dodge another
> potential 
> nomenclatural timebomb rooted in the _Spinosaurus_
> hypodigm.  (BTW, I'm not arguing that _Spinosaurus_
> is a chimera, only that the suggestion that it is
> adds 
> another level of uncertainty to the the phylogenetic
> nomenclature of basal Tetanurae.)

If _Spinosaurus_ is a chimera, where would that place
the dorsal vertebrae?  Are there any features of the
vertebrae which unite the specimen with _Suchomimus_?
Dr. Sereno's original description of _Suchomimus_
doesn't mention any:

http://www.projectexploration.org/suchomimus.htm

An update on the original _Spinosaurus_ material
doesn't touch on this issue either:

http://www.geocities.com/stephvern/spino-newinfo.pdf

Guy Leahy

> 
> 
> Interestingly, it's been suggested that _Suchomimus
> tenerensis_ be sunk into _Baryonyx_.  If (as Denver
> suggests) _Baryonyx_ is sunk into _Suchosaurus_,
> then 
> _Suchomimus tenerensis_ would become _Suchosaurus
> tenerensis_.  Hey. it could happen.... ;-)
> 
> 
> > I still prefer the name Baryonyx.
> 
> 
> Alas, aesthetic preferences are not covered by the
> ICZN.  There's a lot of god-awful dinosaur names I'd
> like to see the back of...
> 
> 
> Cheers, 
> 
> Tim
>