Evolution of the Pterosaur Palate – part 7: Pterodactylus and Germanodactylus

Earlier we looked at basal pterosaur palatesdimorphodontoid palatescampylognathoid palates, pre-azhdarchid palates, pre-ctenochasmatids and pre-ornithocheirids. Here in part 7 we’ll look at the pterosaur palate from Scaphognathus to Pterodactylus longicollum (aka: Diopecephalus, Fig. 1) and to Germanodactylus rhamphastinus, following the phylogenetic order recovered in the large pterosaur tree). As previously mentioned, the pterosaur palate has been largely overlooked, unless it was specifically exposed.

Figure 1. Click to enlarge. Evolution of the pterosaur palate from Scaphognathus to Pterodactylus and Germanodactylus.

Figure 1. Click to enlarge. Evolution of the pterosaur palate from Scaphognathus to Pterodactylus and Germanodactylus.

No. 31
Distinct from the Maxburg specimen of Scaphognathus (No. 110 in the Wellnhofer 1970 catalog), No. 31 was smaller overall with a sharper premaxilla. The medial two premaxillary teeth extend anteriorly. The teeth are smaller and more homodont. The lateral process of the ectopalatine was more robust. The pterygoids were straighter.

Ningchengopterus
Distinct from No. 31, the palate of Ningchengopterus was longer posteriorly with more gracile elements, especially the pterygoid.

Pterodactylus scolopacicps, specimen No. 21
Distinct from Ningchengopterus, the palate of the No. 21 specimen of Pterodactylus was longer still with a more robust vomer. The pterygoids were essentially straight and underlapping the ectopalatines.

Pterodactylus antiquus, specimen No. 4
Distinct from P. scolopaciceps, the palate of the No. 4 specimen of Pterodactylus had smaller teeth and a rounder premaxilla tip. The pterygoid (still hidden beneath a thin layer of limestone) was more robust.

Pterodactylus longicollum, specimen No. 58
Distinct from P. antiquus, the palate of the No. 58 specimen of Pterodactylus (Diopecephalus) had larger teeth, a broader set of vomers, a broader palate and the pterygoids extended over the maxilla (but these may be only the anterior processes of the ectopalatine). The lateral process of the ectopalatine was fenestrated.

No. 12
At the base of the Germanodactylia and derived from a sister to the Maxburg specimen of Scaphognathus (Fig. 1), is tiny No. 12. There is very little difference in the palate, except the medial pterygoid is bifurcated. The lateral process of the medially turned pterygoid became a new anterior process in the Maxburg specimen of Scaphognathus. In No. 12, that process is much longer, reflecting the increased length of the rostrum.

Germanodactylus rhamphastinus, specimen No. 64
Overall larger than and distinct from No. 12, the No. 64 specimen of Germanodactylus rhamphastinus has a larger maxilla palate area. The anterior medial process is longer, but the lateral process, if present, was not identified.

Trends
In this clade the trend was toward a larger contribution to the palate by the maxilla and layering of the pterygoid beneath the ectopalatine. In the Pterodactylus lineage the pterygoids were parallel to each other. In the Germanodactylus lineage the pterygoids formed a triangle.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

Evolution of the Pterosaur Palate – part 6: Eudimorphodon to Cearadactylus

Earlier we looked at basal pterosaur palatesdimorphodontoid palatescampylognathoid palates, pre-azhdarchid palates and pre-ctenochasmatids. Here in part 6 we’ll look at the pterosaur palate from Eudimorphodon to Haopterus (Fig. 1, following the phylogenetic order recovered in the large pterosaur tree), then finish up with three more derived ornithocheirds (Fig. 3).

The evolution of the pterosaur palate from Eudimorphodon to Haopterus.

Figure 1. Click to enlarge. The evolution of the pterosaur palate from Eudimorphodon to Haopterus.

Jianchangnathus
The ectopalatine and pterygoid of the primitive scaphognathid, Jianchangnathus, were little changed from those of Dorygnathus the Donau specimen.

The ectopalatine (pink) and pterygoid (green) of Jianchangnathus.

Figure 2. The ectopalatine (red) and pterygoid (green) of Jianchangnathus.

Pterorhynchus
Distinct from the Donau specimen of Dorygnathus, the palate of Pterorhynchus was longer with (perhaps) a shorter maxillary contribution to the palate. The lateral processes of the ectopalatine were more robust.

Scaphognathus, specimen No. 109
Distinct from Jianchangnathus, the palate of the No. 109 specimen of Scaphognathus had a shorter ectopalatine and V-shaped anterior processes to the pterygoid, which was largely ventral to the ectopalatine.

Scaphognathus, specimen No. 110
Overall much smaller than No. 109, in No. 110 the pterygoids were laterally bowed with a longer lateral process than medial one.

Gmu 10157
Distinct from the 110 specimen of Scaphognathus, Gmu 10157 was overall much smaller and had a much larger pterygoid with several medial processes. Overall the skull was much broader posteriorly to accommodate the large eyeballs.

TM 13104
Another tiny pterosaur, TM 13104 reduced the length of the main body of the pterygoid, but elongated the lateral process to underlap both processes of the ectopalatine.

No. 30
Distinct from TM 13104, the palate of No. 30 is similar, but the pterygoids have a lateral process that contacts the cheek. The two ectopalatine process and the anterior pterygoid all lap each other.

Cycnorhamphus
Overall much larger than No. 30, Cycnorhamphus had a similar palate with forward angled pterygoid lateral processes lined anteriorly by the ectopalatine. The vomers were fused and robust.

Feilongus
Distinct from Cycnorhamphus the palate of Feilongus was extremely elongated. The pterygoid was also elongated and the lateral processes were angled posteriorly, as in No. 30. The lateral process of the ectopalatine was round and robust.

Haopterus
Distinct from No. TM 13104 (No. 34) the palate of Haopterus was elongated with a largely exposed set of vomers. The palatine portion of the ectopalatine was dorsal to and largely hidden by an anterior process of the pterygoid. The ectopterygoid portion was parallel to these processes, but also produced a lateral process to contact the cheek.

Ornithocheirid palates.

Figure 3. Ornithocheirid palates.

Coloborhynchus
Distinct from Haopterus, the palate of Coloborhynchus included a smaller, layered  and very gracile ectopalatine and pterygoid.

Criorhynchus
Distinct from Coloborhynchus, the palate of Criorhynchus had a more robust pteroid and ectopalatine.

Cearadactylus
Distinct from  Criorhynchus, the palate of Cearadactylus was much longer and narrower overall with a longer medial maxilla suture ventrally.

Trends
In this clade (which we will finish next), the trend, once again, is to expand the maxillary portion of the palate posteriorly while the ectopalatine and pterygoid became more robust. Apparently it happened more gradually or slowly in the ornithocheirid clade. The posterior elements became layered one over the other beginning with the small Scaphognathus specimens. In cycnorhamphids the pterygoid produced a lateral process that contacted the cheek.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

Evolution of the Pterosaur Palate – part 5: Eudimorphodon to Pterodaustro

Earlier we looked at basal pterosaur palatesdimorphodontoid palates, campylognathoid palates and pre-azhdarchid palates. Here in part 5 we’ll look at the pterosaur palate from Eudimorphodon to Pterodaustro (following the phylogenetic order recovered in the large pterosaur tree) which splits Dorygnathoidea in three). Scaphognathids will follow.

Evolution of the pterosaur palate from Eudimorphodon to Pterodaustro.

Figure 1. Click to enlarge. Evolution of the pterosaur palate from Eudimorphodon to Pterodaustro. The WDC specimen of Dorygnathus is shown twice, once as originally reconstructed by Osi et al. (2010) and once with a revised reconstruction with errors corrected.

Sordes
Distinct from Eudimorphodon, the palate of Sordes was wider with more gracile palatal elements.

Dorygnathus, the Donau specimen
Distinct from Sordes, the palate of the Donau specimen of Dorygnathus was longer with larger teeth. The pterygoid had a lateral process. The ectopalatine had a posterior process.

Cacibupteryx
Distinct from the Donau specimen, the palatal portion of the maxillae in Cacibupteryx extended further posteriorly with a triangular shape. The pterygoids were larger and more robust. The ectopalatines were shorter and more robust.
Dorygnathus, the WDC specimen
Osi et al. (2010) described the WDC specimen without providing a museum number. The palate in ventral view seems midway between a triangle and a rectangle. The pterygoids were smaller. The ectopalatines were longer and not fused to one another, even those this is one of the largest dorygnathids.

Dorygnathus, the R156 specimen
This is largely conjecture based on landmarks on the lateral side of the R156 skull.

Dorygnathus purdoni
This 3D skull had a more gracile pterygoid with curled lateral processes. The ectopalatine was robust.

Angustinaripterus
With giant premaxillary teeth, the long narrow rectangular palate of Angustinaripterus was more gracile with a longer posterior process of the ectopalatine. The vomers were more robust.

No. 40
The much smaller dorygnathid, no. 40, had a narrower rostrum with maxillary palate plates extending further posteriorly. The lateral processes of the pterygoids were more robust, serving as bases for the ectopalatines.

AMNH 5147
In this tiny pre-ctenochasmatid the rostrum was much narrower. In AMNH 5147 the two processes of each ectopalatine were nearly parallel to one another. The base of each ectopalatine emerged from the broad anterior process of each pterygoid. These essentially filled the posterior palate.

Gnathosaurus
The anterior teeth were greatly enlarged in Gnathosaurus. The dorsal premaxilla was broader than the anterior maxilla, but the ventral premaxilla was relatively tiny and not expanded. The maxillary plates underlapped (in ventral view) the vomers for a third of their length and extended posteriorly to mid antorbital fenestra. The ectopalatines were robust and nearly twice the length of the much shorter and broader pterygoids.

Pterodaustro
Only the posterior palate is shown for Pterodaustro in figure 1. The maxillary plates extended to beyond the middle of the antorbital fenestra. The ectopalatine has a checkmark shape, nested at the anterior tip of the pterygoid’s lateral process.

Trends
As in the the azhdarchid lineage, the ctenochasmatid lineage gradually increased the length of the rostrum and the maxillary portion of the palate beneath the rostrum with a coincident reduction of the ectopalatine and pterygoid, which became increasingly oriented parallel to the cheeks.

One of my reasons for adding more dorygnathus taxa to the large pterosaur family tree was the apparent midpoint link Angustinaripterus provided between Dorygnathus and Gnathosaurus.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

References
Osi A, Prondvai E, Frey E and Pohl B 2010. New Interpretation of the Palate of Pterosaurs. The Anatomical Record 293: 243-258.