Unforunately Dr. David Unwin has brought us
- the invalid Monofenestrata
- Darwinopterus as the transitional taxon linking long-tails to short-tails.
- Modular evolution
- a 1994 continuation of the deep chord wing membrane misinterpretation of Sordes
From the Unwin 2017 abstract:
“The origin of the pterodactyloid bauplan from that of non-monofenestratan (‘rhamphorhynchoid’) pterosaurs involved extensive anatomical changes and had profound consequences for the evolutionary history of Pterodactyloidea,”
“Evolution of the pterodactyloid skull construction predates the Middle Jurassic, but remains almost completely undocumented by fossils.”
Not really. Dr. Unwin does not include a sufficient number of tiny adult pterosaur taxa. Traditionally he has ignored the tiny transitional taxa that document the origin of the pterodactyloid-grade. He does not want to accept that this grade has been attained four times and two other clades, Anurognathidae and Wukongopteridae, evolve some, but not all pterodactyloid-grade traits.
“Liaodactylus reveals that innovation in pterodactyloid skull anatomy and the appearance of derived features was well underway prior to the Upper Jurassic. Douzhanopterus, a derived NPM, demonstrates that elongation of the metacarpus and reduction of the tail and fifth toe (classic pterodactyloid synapomorphies) also predates the Upper Jurassic, but disjunction in the degree of their development across taxa is not consistent with simple explanations such as ‘adaptation for flight’. Overall, late Early to early Late Jurassic pterosaurs were much more diverse and had a far more complex evolutionary history than heretofore recognized.”
Peters 2007 recognized the ‘far more complex evolutionary history’ that Unwin has yet to accept.
Earlier we looked at Douzhanopterus (Late Jurassic) and found it nested among the primitive members of the Pterodactylus clade. Earlier we looked at Liaodactylus, which nested among the Ctenochasmatidae.
Dr. Unwin still doesn’t get the big picture
due to taxon exclusion in his analyses. Pterodactyloid-grade pterosaurs had four origins (azhdarchids and ctenochasmatids arising from Dorygnathus. Scaphognathus gives rise to pterodactylids and germanodactylids, which give rise to tapejarids and pteranodontids. This topology has been in the literature since Peters 2007, and online since 2011 at ReptileEvolution.com. If you know Dr. Unwin, please steer him gently in that direction.
Unwin D 2017. The complicated and surprisingly early origin of the pterodactyloid bauplan. SVPCA-SPPC Birmingham, abstracts September 12-15, 2017.
Peters D 2007. The origin and radiation of the Pterosauria. Flugsaurier. The Wellnhofer Pterosaur Meeting, Munich 27 online here. (Please ignore the notes on Jesairosaurus and Drepanosauridae, which no longer nest with the pterosaur clade. The latest info is here and here.)
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.