The largest ornithopod (Dinosauria: Ornithischia) from the Upper Jurassic of Europe sheds light on the evolutionary history of basal ankylopollexians.

The article focuses on the discovery and description of a new basal ankylopollexian ornithopod dinosaur, *Oblitosaurus bunnueli* gen. et sp. nov., from the Upper Jurassic Villar del Arzobispo Formation in eastern Iberia (Spain). Based on fossil remains including a dentary tooth, a manual ungual pollex, and an almost complete left hindlimb, phylogenetic analysis places *Oblitosaurus bunnueli* as the basalmost member of Ankylopollexia alongside *Draconyx loureiroi* (Portugal), forming an Iberian clade distinct from contemporaneous North American taxa. The study also supports the monophyly of the genus *Camptosaurus* and proposes a revised definition of Ankylopollexia. Estimated at 6–7 meters in length, *Oblitosaurus bunnueli* is the largest known ornithopod from the Upper Jurassic of Europe and may correspond to large ornithopod tracks found in the Iberian Peninsula, thereby increasing the recognized ankylopollexian diversity in this region during that period.