First dinosaur remains from Ireland

Abstract Several specimens from the Lias Group (Lower Jurassic) of Northern Ireland have been suspected as dinosaurian in origin. Bone histology and morphology demonstrates that two of these, both from the same locality in Co. Antrim, demonstrably are from dinosaurs. We interpret one as the proximal end of the left femur of a basal thyreophoran ornithischian, and tentatively assign it to cf. Scelidosaurus. The other is the proximal part of the left tibia of an indeterminate neotheropod, perhaps a member of the averostran-line similar to Sarcosaurus, or a megalosauroid. These are the first dinosaur remains reported from anywhere in Ireland and some of the most westerly in Europe, and they are among only a small number of dinosaurs known from the Hettangian Stage. Two additional specimens are no longer considered to be from dinosaurs. We interpret one as a surangular or mandible fragment from a large marine reptile, perhaps an ichthyosaur or pliosaur; the other is a polygonal fragment of Paleocene basalt.