A new species of large-sized pterosaur from the Maastrichtian of Transylvania (Romania)

Abstract

The Upper Cretaceous “Hațeg Island” is not only renowned mostly for its peculiar assemblage of dwarf dinosaurs, but also for its Azhdarchidae pterosaurs including giant specimens (e.g. Hatzegopteryx thambema) and medium-sized ones (e.g. Eurazhdarcho langendorfensis), discovered in the Hațeg and Transylvanian basins of Romania. Here, we report a new species of azhdarchid pterosaur, Albadraco tharmisensis gen. et sp. nov. The material refers to two well-preserved “beak” fragments and a cervical vertebra. These fossils were discovered together in a fossil assemblage in the Maastrichtian Şard Formation, located in the southwestern area of the Transylvanian Basin (Alba County, Romania). The association of a premaxilla and a mandibular symphysis from the same specimen is the first ever reported in Europe. The fourth cervical exhibits the best three-dimensional preservation of any azhdarchid mid-cervical vertebra in Transylvania, as all specimens reported previously are poorly preserved (e.g. in E. langendorfensis) or incomplete like the specimen from Pui with a broken condyle. Albadraco tharmisensis represents a new species of a large–sized azhdarchid from the “Hațeg Island”. Its size fits between that of E. langendorfensis and H. thambema, hence confirming the co-existence of medium, large, and giant–sized azhdarchids during the Maastrichtian in Transylvania. The possibility of Ad. tharmisensis being a young Hatzegopteryx is also discussed.