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: Arcticodactyluscromptonellus (comb. nov.), Austriadraco dallavecchiai (gen. et sp. nov.) and Bergamodactyluswildi (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 Arcticodactyluscromptonellus 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,Bergamodactyluswildi and Carniadactylus rosenfeldi have reached at least OS5, which demonstrates that the anatomical differences among them cannot be explained by ontogeny. Moreover, Bergamodactyluswildi 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.