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Jouve's and Tacquet's Ctenochasma sp.
Stephane JouvÃ© asked that I post this letter to the dinosaur list.
With all honors, I do so now without comment, other two preliminary notes:
1) a phylogenetic analysis of every decent specimen in the inventory of the
Pterosauria reveals that that the Pterodactyloidea is paraphyletic, with
separate origins for the Ctenochasmatoidea, etc. and the Azhdarchidae, etc.
from various Dorygnathus specimens; and the Cycnorhamphidae +
Ornithocheiridiade, etc. and Pterodactylidae + Germanodactylidae etc. etc. from
various Scaphognathus (themselves derived from basal Dorygnathus). Thus
comparing brain sizes in Pteranodon and Tapejara to Ctenochasma crosses many
more taxon lines than comparisons to Dorygnathus (Parapsicephalus) purdoni and
the micro ctenochasmatids. The latest single tree can be seen at
And 2) questions regarding identification of bones need to go through two
steps: labeling the specimen and creating a valid reconstruction. Problems
arising with misidentification (and they are legion in the literature) usually
can be discovered during the reconstruction process. And if I'm at fault here,
then I'll make corrections.
Sorry for the delay of my reply, but I am very busy at the moment.
So, I provide some short comments to your comments below. I still disagree on
all your comments and on your
reconstruction, and I think many answer to your comments are in the paper.
I as very happy to discuss with you, and if you have other comments, no
Have you seen the specimen ?
Thank you for your reply. And again, congratulations on getting a paper
Please take the following notes and criticisms kindly. I have learned
much in my cladistic study of all the pterosaurs and not very much of
what I have learned is in the literature yet. So much of what you are
about to read will be new to this science.
In a strange twist, I have to retract part of what I mentioned in my
first email. Let me explain:
The Saint-Dizier specimen is a match for the skull crushed
dorsoventrally [PTHE 1951.84 (Mayr 1964, No. 70 of Wellnhofer 1970,
1991)] that has come to be considered the icon for Gnathosaurus-- and
not a match forÂ B St 1935 I 24, No. 65 of Wellnhofer 1970, Specimen 3
of BuisonjÃ© 1981 the completely articulated specimen that has come to
beknown as the icon for Ctenochasma.
But the Saint-Dizier specimen _does match_ the Ctenochasma holotype, a
large toothy mandible.
Remember, the mandible of Gnathosaurus (the holotype specimen) is not
spoon-billed either, just the rostrum is.
A reconstruction of the new Saint-Dizier specimen apppears at:
Characters in the Saint-Dizier specimen matching No. 70 and not
Matching No. 65:
The antorbital fenestra is larger
than the orbit.
Ontogenetic character !!!!!! nÂ°65 is juvenile, and sof is larger than orbit
The orientation of The jugal, (mislabeled quadratojugal) which cannot be
No. 70 is angled higher than in No. 65 and similar to more primitive taxa. The
upper temporal arch is as high as the orbit, as opposed to No. 65, where it is
The quadratojugal is not misslabelled (see below). The upper temporal arch is
also low here.....
The teeth may not be as robust as in the dorsoventrally crushed skull,
but another gnathosaurine, Plataleorhynchus, has even more gracile
The teeth are much close from each other, much numerous (see Fig. 10), and much
thinner and longer than in Gnathosaurus.
Note the broad nasals overlap the premaxilla dorsal to the antorbital
fenestra (mislabeled the premaxilla), as in all Ctenochasmatids. The
premaxilla is overlapped anteriorly by the maxilla, again as in all
Ctenochasmatids. The lacrimal is a broad plate (mislabeled the nasal),
so the mysterious nasal fenestra becomes the more typical lacrimal
Mislabeled premaxilla?????? Which figure???? In pterodactyloidea the
premaxillae reach the level of the orbits.....I am not agree at all with your
labelling of the skull bones....are we discussed on the same group?????
Some other labeling errors:
Fig. 1: The "prefrontal" is a part of the nasal. The real prefrontal is
over the orbit.
No, the lacrimal is clearly missing and covered laterally the nasal (present).
Moreover, what you label nasal (I still thinking it is the prefrontal) does not
reach the nasoantorbital fenestra (it reaches in pterodactyloidea).
Fig. 2: The right quadratojugal is the postorbital process of the
No!!!!! The postorbital process of the jugal is located above the
quadratojugal. There is a clear suture between the two bones!!!! Don?t forget
it is an internal view.
The post orbital is too low in the tracing. The actual PO is just above
??????? It is not a reconstruction of the skull but a draw of the specimen!! I
drawn what I?ve seen, not
what I should see!!
Fig. 4. The "brain" in the Saint-Dizier specimen is much too small.
NO!! The brain is much smaller than the external bones of the skull (see
This needs to be reexamined. It cannot be compared to Pterandon and Tapejara
which are not related, but must be compared to sister taxa, including
Parapsicephalus and P.
Why can they not be compared to Pteranodon or Tapejara??? They are also
Pterodactyloidea!!!! No ? P elegans is juvenile (see text) and Pareapsicephalus
is not a pterodactyloidea (I am not sure on that). The condition of the skull
in Pterodactyloidea is only known in Pteranodon and Tapejara (the true shape of
Fig. 9. The uneven ventral margin of the dentary in a
specimen labeled, Pterodactylus "kochi" B St 1878 VI 1 [No. 13 of
Wellnhofer 1970] noted as an example of a fossilization artifact, is
not. an artifact. Instead this character is a genuine feature and the
genesis of the deep mandible found in some Nyctosaurus and Pteranodon, which
are sister taxa. (See pterosaurinfo.com > taxa > family tree.
I completely desagree with that, and the mandibular shape in P. Kochi is
clearly (for me) an fossilization artifact (see text). Moreover, in my
phylogenetic analysis Pteranodon is far from P. Kochi...
You stated 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.Â The
holotypes of both can be found at
pterosaurinfo.com/p_antiquus_recon.html and pterosaurinfo.com/no23_recon.html
for comparison. There's no
comparison, although I would imagine that you did not consider the holotype of
P.kochi, but rather the referred specimens of P. kochi, that we're all familiar
with that are closer to No. 4. StÃ©phane, from now on, all pterosaur papers
need to dispense with applied names, especially when dealing the
ctenochasmatids and pterodactylids, because so many taxa are
Instead a more precise way to identify specimens is by specimen
C. porocristata or porocristatum is closer to
Huanhepterus and the azhdarchids in a paper coming soon.
So it is
unrelated to Ctenochasma. See pterosaurinfo.com for a tracing and
Argh!! In my phylogenetic analysis azhdarchids is far from Ctenochasma or
Gnathosaurus and I?m still thinking that.
The nomenclature problem that you have unintentionally unearthed is
interesting. Ctenochasma roemeri (Meyer 1852) is the holotype specimen.
As you 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.
I still desagree with you on your taxonomic revision.
I know this means many changes in thinking. I've experienced the
Changes during the last two years of my studies. It is hard to digest, I know.
I can digest much more than you seem to think....
Your critisism are interesting, but you seem to not take into account a lot of
things. First: have you seen the specimen?? If you don?t, how can you provide a
reconstruction???? I worked during one year on this secimen, and, if some
points can be discussed, I still desagree with nearly all your comments.......
Please, can you provide this discussion on the dinosaur list? I?ve seen
your comments on my paper, and I?d like my comments was on too.
(have you a problem with Chris Bennett ???? He only did some comments, mainly
on taxonomical points, but this work is mine, even if I thank Dr. Bennett again
for his constructive and argumented comments.
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