Year-classes of pterosaurs from the Solnhofen limestone of Germany: Taxonomic and systematic implications

Statistical analyses of measurement data and morphological studies of pterosaur fossils from the Upper Jurassic Solnhofen Limestone of Germany reveal the presence of year-classes resulting from repeated seasonal sampling of pterosaur populations. Year-classes of Rhamphorhynchus had previously been named as separate species. Similar year-classes of nominal species of Pterodactylus indicate that size-classes of some pterodactyloid species also had been named as separate species or genera. Lumping the nominal species reduces the Solnhofen pterosaur fauna to a small number of large species, and suggests that some long-held ideas about pterosaur evolution are incorrect.