A recent paper by Palmer and Dyke (2011) revised the wing shape and orientation of pterosaurs based on mechanical and aerodynamic constraints. Unfortunately they got the anatomy wrong in several instances spelled out below. Those mistakes affected their results.
Once Again, the Deep Wing Paradigm Has Been Promoted as True
Palmer and Dyke (2011) reported, “We know that the margin of the pterosaur wing membrane was unconstrained posteriorly and attached distally to the ankle and body.” Without critical examination, they accepted and cited Elgin, Hone and Frey (2011) and Kellner et al. (2010) which were critically reexamined here and here.
Palmer and Dyke (2011) Made Several Mistakes
In airplanes, birds and bats the CG (center of gravity) is at the wing spar root (between the shoulder joints). Presumably the same was true of pterosaurs. Move the elbow back to where it belongs and add flesh to the thighs based on pelvis length to add more mass aft of the CG. Permit the aktinofibrils to make a spoon-shaped wingtip, as they do in fossils. Split the uropatagium into uropatagia (as in Sharovipteryx and Sordes) and move the femur laterally to create an airplane-like horizontal stabilizer. No pterosaur is preserved with wing membranes attached to the ankles. Rather the membranes always are directed to the elbow with a small fuselage fillet attached to the femur.
The great majority of pterosaur workers, including the two anonymous referees who green-lighted this paper, follow the Palmer and Dyke (2011) model (on the right), despite its falsehoods and problems. The heretical view (on the left) follows the fossil evidence strictly. If anyone can produce and trace a specimen with a deep wing membrane attached at the ankle, I’ll marry their sister.
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.
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
Kellner AWA, Wang X, Tischlinger H, Campos DA, Hone DWE and Meng X 2010. The soft tissue of Jeholopterus (Pterosauria, Anurognathidae, Batrachognathinae) and the structure of the pterosaur wing membrane. Proc Royal Soc B 277: 321–329
Palmer C and Dyke G 2011. Constraints on the wing morphology of pterosaurs. Proceedings of the Royal Society B. published online 28 September 2011.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Schaller D 1985. Wing Evolution. In: Hecht M, Ostrom JH, Viohl G and Wellnhofer P, eds, The Beginning of Birds. Proceedings of the International Archaeopteryx Conference, Eichstätt 1984, (Freundes Jura Museum, Eichstätt), pp. 333–348.
Stromer E 1910. Bemerkungen zur Rekonstruktion eines Flugsaurier-Skelettes. Monatsberichte der deutschen Geologischen Gesellschaft 62, 85–91.