Comments on Triassic pterosaurs with discussion about ontogeny and description of new taxa

Abstract

Eudimorphodon ranzii was the first Triassic pterosaur to be described and several specimens have been referred to this taxon mainly based on the presence of multicuspid teeth. Since this dental feature has been observed in several other pterosaurs, the revision of some specimens assigned to Eudimorphodon shows that they represent new taxa as follows: Arcticodactylus cromptonellus (comb. nov.), Austriadraco dallavecchiai (gen. et sp. nov.) and Bergamodactylus wildi (gen. et sp. nov.). A preliminary analysis of pterosaur ontogeny resulted in the recognition of six distinct ontogenetic stages (OS1-6). According to this classification, the holotype of Arcticodactylus cromptonellus has reached OS2, and although being ontogenetically much younger than others, the conspicuous anatomical differences lead to its exclusion from Eudimorphodon. The holotypes of Austriadraco dallavecchiai, Bergamodactylus wildi and Carniadactylus rosenfeldi have reached at least OS5, which demonstrates that the anatomical differences among them cannot be explained by ontogeny. Moreover, Bergamodactylus wildi reaches about 60% of the maximized wingspan of Carniadactylus rosenfeldi and further concurs that these specimens collected in distinct Triassic Islands of Europe are not conspecific. The present study increases the diversity of Triassic flying reptiles and further pushes the origins of this clade back to at least the Middle Triassic.

Rebuttal of Martin-Silverstone et al. 2017, ‘Reassessment of Dawndraco kanzai Kellner 2010 and reassignment of the type specimen to Pteranodon sternbergi Harksen, 1966’

“…According to Bennett (1993), these bones are among the last to fuse, shortly before the animal reaches skeletal maturity. I have also made similar observations, although other elements fuse at a latter stage (Kellner 2015). Nevertheless, the fusion of these elements appears to indicate that UALVP 24238 has reached a late ontogenetic stage at time of death.…”

Premaxillary crest variation within the Wukongopteridae (Reptilia, Pterosauria) and comments on cranial structures in pterosaurs

“…This has been shown to be true at least for some material of the Pteranodon-complex and seems also to have been the case for the Wukongopteridae. Perhaps more detailed studies of deposits with large amount of specimens that might have been part of the same or closely related populations like the occurrences of Caiuajara dobruskii and Hamipterus tianshanensis (and others that might come to light) have the potential to provide a step further into the discussion of several paleobiological questions concerning flying reptiles, including sexual dimorphism and ontogeny (Kellner 2015). Meanwhile the variation in shapes and sizes of cranial crests that are found in pterosaurs, associated with other morphological features, should not be understated as being a powerful tool for understanding their diversity.…”

“…They have been considered to represent three genera, Wukongopterus, Darwinopterus, and Kunpengopterus (Wang et al 2009, 2010, 2015, Lü et al 2010, 2011a, or remained indeterminate (Cheng et al 2016). Two additional individuals were also referred to this clade.…”

“…The holotype of Kunpengopterus sinensis (IVPP V 16047) and ZMNH M8802/IVPP V 18043, an individual that was associated with eggs, lack an ossified cranial crest (Wang et al 2010, 2015, Lü et al 2011a.…”

New azhdarchoid pterosaur (Pterosauria, Pterodactyloidea) with an unusual lower jaw from the Portezuelo Formation (Upper Cretaceous), Neuquén Group, Patagonia, Argentina

“…The bone surface is also not well preserved. Sutures are not observable due to fusion, a common feature of lower jaws of derived pterosaurs, where all elements, particularly the dentaries, tend to fuse very early during ontogeny (e.g., Kellner 2015). Only a small groove indicating the contact surface between the dentaries is observed on the dorsal region, close to the posterior margin of the symphysis (Figs.…”