[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: what's wrong with Jouve's Ctenochasma?



> The lacrimal is a broad plate (mislabeled the nasal),
> so the mysterious nasal fenestra becomes the more typical lacrimal
> fenestra.

What mysterious nasal fenestra? Jouve always talks of a "nasoantorbital
[sic] fenestra", and it's in the expected position. But what, if
anything,
is a "lacrimal fenestra"? The lacrimal duct???

Look for the ?Obc. Figure 3. In the middle of Jouve's "N."



> Some other labeling errors:
> Fig. 1: The "prefrontal" is a part of the nasal. The real prefrontal
is
> over the orbit.

Probable... from my dinosaurocentric point of view.

Time to come back to pterosaurs, David.


> Fig. 2: The right quadratojugal is the postorbital process of the
jugal.

I'd say... judging from its position, if it isn't a quadratojugal, then
it's
a quadrate. A postorbital process of what ought to be the jugal, and is
labeled as such, is present above the qj.

You're losing me. Go back to the photo.



> The post orbital is too low in the tracing.
> The actual PO is just above it.

No. Look where the two temporal fenestrae are.

Go back to the photo.


> Fig. 4. The "brain" in the Saint-Dizier specimen is much too small.

Why do you simply state this as a matter of fact, even though Jouve
makes
quite clear why he disagrees? Why should the brain, for example, keep
the
same relative size as in the baby called "*Pterodactylus elegans*" (Fig.

4B)? Why shouldn't it be as small as in *Tapejara* and *Pteranodon*?

Now you've lost me. Because Tapejara and Pteranodon are way off on
another branch, while P. elegans is a sister taxon. Interesting that
Jouve's talks about Tapejara and Pteranodon without showing these key
(for his argument) taxa? Why? Because the drawings weren't available,
judging by what was used.



> Fig. 9. Jouve points to the uneven ventral margin of the dentary in a
> specimen labeled, Pterodactylus "kochi" B St 1878 VI 1 [No. 13 of
> Wellnhofer 1970] as an example of a fossilization artifact, but it is
> not. Instead this character is a genuine feature and the genesis of
the
> deep mandible found in some Nyctosaurus and Pteranodon.

Why do you simply state this as a matter of fact, even though Jouve
gives a
quite plausible explanation for why he thinks it's just squished?

You have the cladistic analysis. Use it.



> Jouve states that P. antiquus [BSP Nr. AS I 739, No. 4 of Wellnhofer
> 1970] and P. kochi [B St ASXIX 3 (plate). SMF No. R 404
(counterplate).
> No. 23 of Wellnhofer 1970]
> represent two different growth stages of single species.  The
holotypes
> of both can be found at pterosaurinfo.com/p_antiquus_recon.html

dentary looks squished

> and pterosaurinfo.com/no23_recon.html for comparison.

What have you done to its vertebral column? -- Other than that, it looks

juvenile. Short neck, short snout and all.

You have the cladistic analysis. Use it.



> There's no comparison,
> although I would imagine that Jouve is not considering the holotype,
but
> rather the referred specimens of P. kochi, that we're all familiar
with
> that are closer to No. 4.

When looking for No. 4, I learned that this is the holotype of *P.
antiquus*... and found this
http://www.pterosaurinfo.com/p_antiquus_rostrum.html. It is dead obvious

that the multiple nares are neurovascular foramina and/or breakages --
that's why they look so irregular.

And that's why the nasal and jugal border them both? And they are
present in every taxon higher than Scaphognathus?



> C. porocristata or porocristatum will turn out to be closer to
> Huanhepterus and the azhdarchids in a paper coming soon. So it is
> unrelated to Ctenochasma.

Then why is its skull absolutely identical to those of other *C.
elegans*,
apart from ontogenetic features?

Show me what you mean by "absolutely identical." For my argument you'll
note many differences at pterosaurinfo.com. By the way, loyal readers,
D.M. has yet to show me _anything_ he professes.



> Dr. Christopher Bennett is acknowledged  for "numerous suggestions,
> comments and criticisms [which] improved this work significantly."

Er... and?

It shows.



> The nomenclature problem which Jouve has unintentionally unearthed is
> interesting. Ctenochasma roemeri (Meyer 1852) is the holotype
specimen.
> As Jouve noted, it is quite similar to the Saint-Dizier specimen.
> Working backwards, that means that our traditional "Gnathosaurus" No.
> 70, may really be Ctenochasma. And our traditional Ctenochasma, No.
65,
> may have to be renamed.

This looks possible, although it's just a splitter vs lumper problem at
the
moment.


So start lumping or splitting  -- if you dare.

dp