Dimorphodon macronyx (Buckland 1829, Owen 1859) Hittangian, Early Jurassic ~195 mya was one of the first pterosaurs found and described. Derived from a sister to Preondactylus, Dimorphodon phylogenetically preceded Peteinosaurus (MCSNB 3359), but chronologically succeeded it.

Overall larger and distinct from Preondactylus, the skull of Dimorphodon was taller overall with a convex dorsal profile and slender skull elements. The anterior teeth were enlarged. The rear of the skull tilted posteriorly. The maxilla had a more exaggerated convex ventral margin. There was no mandibular fenestra as described below.

The cervicals were slightly larger. Fewer dorsals were present.

The scapulocoracoid was fused. The wing was proportionately larger. Pedal digit IV extended further than the other digits.

There are three fairly complete specimens, BMNH 1034, 1035 and 41212.

ABOVE: Nesbitt and Hone (2010) proposed a mandibular fenestra for this Dimorphdon specimen (BMNH 4212), evidently not realizing the surangular had drifted dorsally and what they considered to be the angular was actually a displaced pterygoid (or the continuation of the anterior articular, they both have similar shapes). Such a mistake is easy to make when tracing a specimen with little attention to detail and no phylogenetic analysis. No pterosaur has a mandibular fenestra. No pterosaur has a deep jugal flange. A suite of characters indicates that pterosaurs are not archosaurs, they are lepidosaurs. Turtles are closer to pterosaurs than dinosaurs are! (And yes, the present analysis can demonstrate that by removing ALL lepidosauromorphs except turtles).

BELOW: The Mary Anning specimen of Dimorphodon with no mandibular fenestra. The left and right mandibles have slid past one another with the lower (left) mandible partly covered or destroyed.

Buckland W 1829. Proceedings of the Geological Society London, 1: 127

Owen R 1859. On a new genus (Dimorphodon) of pterodactyle, with remarks on the geological distribution of flying reptiles." Rep. Br. Ass. Advmnt Sci., 28 (1858): 97–103.

Nesbitt SJ and Hone DWE 2010. An external mandibular fenestra and other archosauriform character states in basal pterosaurs. Palaeodiversity 3: 225–233

Padian K 1983. Osteology and functional morphology of Dimorphodon macronyx (Buckland) (Pterosauria: Rhamphorhynchoidea) based on new material in the Yale Peabody Museum, Postilla, 189: 1-44.

Sangster S 2001. Anatomy, functional morphology and systematics of Dimorphodon. Strata 11: 87-88.

Sangster S 2022. The osteology of Dimorphodon macronyx, a non-pterodactyloid pterosaur from the Lower Jurassic of Dorest, England. Monographs of the Palaeontological Society 175, 221 (661).

wiki/Dimorphodon