A Spanish saltasauroid titanosaur reveals Europe as a melting pot of endemic and immigrant sauropods in the Late Cretaceous.

A new lithostrotian titanosaur, Qunkasaura pintiquiniestra gen. et sp. nov., is described based on a single partial skeleton from the late Campanian-early Maastrichtian fossil-site of Lo Hueco (Cuenca, Spain). This new taxon is supported by an exclusive combination of characters that highlights strong convergences with members of the South American Aeolosaurini. Qunkasaura allows to reorganise the complex phylogenetic relationships of the increasingly diverse finicretaceous sauropods of Europe. Phylogenetic analyses places Qunkasaura within Saltasauridae and possibly Opisthocoelicaudiinae, together with Abditosaurus. A new clade is established, Lohuecosauria, including Saltasaurus, Lohuecotitan, their most recent common ancestor and all its descendants. Two distinct Ibero-Armorican Campanian-Maastrichtian saltasauroid lineages are recognised: (i) Lirainosaurinae that is exclusive from Europe, and (ii) a saltasaurid lineage with possible opisthocoelicaudiine affinities, with a Laurasian distribution. Lirainosaurinae was a relict lineage including possible dwarf forms that evolved in isolation after reaching Europe before the Late Cretaceous through the Apulian route. The occurrence of opisthocoelicaudiines in Europe may be the result of a Late Cretaceous interchange between Europe and Asia. No evidence of insular dwarfism is found in the Ibero-Armorican opisthocoelicaudiines suggesting that they may have been newcomers to the area that arrived before the 'Maastrichtian Dinosaur Turnover' in southwestern Europe.