The Early Cretaceous ornithocheiroid pterosaur Istiodactylus latidens (Pterosauria, Archosauria, Reptilia) from the Wealden Supergroup of the Isle of Wight, southern England, has a distinctive dentition of labio-lingually compressed, sub-triangular tooth crowns with a triangular osseous projection at the dentary symphysis that occluded into a similarly shaped diastema between the first teeth of the left and right premaxillae and functioned as an odontoid (pseudotooth). A somewhat similar triangular bony projection occurs also in the istiodactylid Longchengpterus zhaoi from the Cretaceous of China. The possession of an odontoid at the dentary symphysis may be autapomorphy for Istiodactylidae. The apparent lack of an odontoid in other istiodactylids (Liaoxipterus brachyognathus Dong and Lü, 2005 and Istiodactylus sinensis Andres and Ji, 2006) may be a consequence of poor preservation.
- Wealden Supergroup