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re: pterosaur palate paper, Osi et al. 2010

New Interpretation of the Palate of
THE ANATOMICAL RECORD 293:243–258 (2010)

The new paper on pterosaur palates presents some interesting and much needed 
data. It also, for some strange reason, says one thing and does another when it 
comes to conclusions.

The good:

1. A wonderful 3D specimen of Dorygnathus is revealed. It's a big one, about 
50% longer than the others. 

2. Supplementary Data provides a good history of the understandings and 
misunderstandings of the pterosaur palate. Seems we can blame Williston 1902 
and later Huene 1914 for misidentifying the palatal plate of the the maxilla as 
the palatine when earlier authors Newton (1888), Seeley (1901), Woodward 
(1902), had it right.

3. Nice to get confirmation. They gave credit to Peters 2000 for recognizing 
the correct labels in this fashion: "More recently, Peters (2000) identified 
the broad palatal bone as the ‘‘medial maxilla process’’ and briefly noticed 
that this structure has been mislabeled as the palatine by earlier authors. 
However, he did not give a detailed explanation why he considered this palatal 
region as part of the maxilla."  

The reason was the very clear homologies with Macrocnemus and Sharovipteryx. 

4. They found a specimen in which the ectopterygoid and palatine were unfused 
(which is a revelation). If this is indeed a juvenile character, then this 
specimen was larger yet as an adult.

5. A foramen incisivum was found, also a novelty. 

6. They found "Apertura maxillo-premaxillaris, " also a novelty.

7. Their Figure 8 was a good reconstruction of the available material, with the 
palatine in close association (forming an L shape) with the ectopterygoid. 
These elements are fused in virtually all other pterosaurs, as shown in the 
pterosaurs in their Figure 9.

The not-so-good

1. Comparisons were only made to archosaurs when in fact no line up of 
archosaurs documents a gradual increase in pterosaurian characters and all 
archosaurs have reduced lateral digits (#4 manus, #5 pes). They report: "Hone 
and Benton (2007, 2008) provided new evidence to support the origin of the 
Pterosauria within Archosauria and we follow their definition here." 
Unfortunately, Hone and Benton made their test by omitting the data from 
Peters, 2000, including omitting the two fenestrasaurs closest to pterosaurs 
and scoring the other two for only a quarter of their available characters, so 
their so-called 'test' was no test at all, but a foregone conclusion with only 
one possible outcome.  

2. Figure 3 is a multiview photo of the premaxilla of the new specimen. 
Unfortunately the authors failed to recognize the pmx/mx suture essentially 
extending from the antorbital fenestra not quite to tooth #4. So a healthy 
portion of the maxilla is present here laminated to the pmx. The break occurred 
at the narrowest portion below the naris. 

3,The sagittal rdge (SI) in the pmx is the paired, fused, anterior vomers. 

4. Considering the proportions of the very elongate premaxilla, longer than in 
any other Dorygnathus of which I am aware, and as long as the maxilla, this is 
probably a derivation of Dorygnathus, but sufficiently distinct to merit its 
own genus. I would encourage the authors to erect a new genus and perform a 
phylogenetic analysis of all known Dorygnathus specimens to confirm the new 
specimen's closest relations. There is an unrecognized variety in Dorygnathus 
that needs to be explored. I don't think this specimen is basal to any known 
taxa, which all have a shorter pmx.

5. Fig. 9 Misidentified the entire broken rostrum of Gnathosaurus as the 
premaxilla, when it should have included only the first four teeth.

6. Paradoxically, and contra the evidence of their specimen, the hypothetical 
reconstructions in Figure 11 separate the palatine from the ectopterygoid, 
giving each a separate articulation on the pterygoid for no apparent reason, 
other than possibly this is the pattern seen in crocodilians. No pterosaur 
specimens document this configuration, and certainly not their very special 
"Dorygnathus" or their also included Rhamphorhynchus and Gnathosaurus. 
Reconstructions need to be consistent with the data. 

7. Figure 11 also purports to extend the premaxilla in "(B) pterodactyloid 
pterosaurs" to include over a dozen teeth. This is also wrong. The premaxilla 
in all pterosaurs includes up to 4 teeth, no more.  

8. The authors need to reconstruct the posterior vomers lateral to the anterior 
pterygoids, not medial. 

9. The authors ascribe a lateral pterygoid process contacting the jugal to all 
basal pterosaurs, but this process is restricted to Rhamphorhynchus.

David Peters
St. Louis

cc: OA, EP, MW, DF, DML