An awkward Dorygnathus model from a museum in Karlsruhe, Germany

Middle Jurassic Germany was home
to quite a few Dorygnathus specimens (Fig. 1), among them the Donau specimen (Fig. 2), a basal dorygnathid in the Large Pterosaur Tree (LPT, 261 taxa) with shorter fingers and gracile wings.

So it comes with equal parts surprise and disappointment
that the Dorygnathus model on display at the Natural History Museum, Karlsruhe, Germany (Paläozoologe Staatliches Museum für Naturkunde Karlsruhe) is so awkwardly posed (Fig. 3). Apparently this reflects the current mythology of a wing-launch in pterosaurs. It cheats pterosaur morphology in a similar fashion.

The Karlsruhe Dorygnathus model manus
(Fig. 2) relocates the three free fingers to the top of the wing finger, raising the fingers off the substrate and impressing the wing finger into the substrate. This is just the opposite of all pterosaur manus impressions in which fingers 1–3 impress and wing finger 4 does not. No pterosaur specimens preserve this orientation. Rather this relocation comes from the imagination of pterosaur workers beginning with Michael Habib. and supported by Naish, Witton and Martin-Silverston 2021.

The Karlsruhe Dorygnathus model pes
(Fig. 2) is plantigrade and extends pedal digit 5 laterally with nothing to do. We’ve known for twenty one years (since Peters 2000a, 2000b; Fig. 6) that pedal digit 5 bent beneath itself helping to support a digitigrade pes in basal pterosaurs like Dorygnathus (FIg. 7). This is documented in Rotodactylus tracks that match the pes of pterosaur precursor, Cosesaurus, with a similar metapodial lateral toe. Plantigrade pterosaur feet with a tiny lateral toe evolved later (Fig. 3).

Pterosaur expert,
NHM Karlsruhe professor Eberhard ‘Dino’ Frey, is probably responsible for the pose and errors in the Karlsuhe model Dorygnathus. Frey was also a co-author on a paper (Elgin, Hone and Frey 2011) that imagined bat-wing pterosaur membranes extending to the ankle (Fig. 8 top) where no such membranes exist. Note the dorsal placement of metacarpals 1–3 in the Elgin, Hone and Frey graphic. These errors are not just a difference of opinion. You might remember that Elgin, Hone and Frey 2011 explained away the factual appearance of Pterodactylus and Rhamphorhynchus narrow chord wings as ‘shrinkage.’ These are examples of professors cheating fossil data to support pet hypotheses and the sale of their textbooks and lectures.

In the Peters 2002 model,
Fig. 5) the three metacarpals are aligned as they are in all tetrapods, flexor surface down. Only metacarpal 4 is rotated axially in order for digit 4 to flex (fold) and extend (fly) in the plane of the wing.

References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111. doi: 10.4202/app.2009.0145
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods.  Ichnos 7:11-41.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.

http://reptileevolution.com/pterosaur-wings.htm
http://reptileevolution.com/pterosaur-wings2.htm