New Ankylosaurian Cranial Remains From the Lower Cretaceous (Upper Albian) Toolebuc Formation of Queensland, Australia

Australian dinosaur research has undergone a renaissance in the last 10 years, with growing knowledge of mid-Cretaceous assemblages revealing an endemic high-paleolatitude Gondwanan fauna. One its most conspicuous members is ankylosaurs, which are rare but nonetheless occur dinosaur-bearing formations spanning uppermost Barremian to lower Cenomanian. Here we describe partial ankylosaur skull from marine Toolebuc Formation exposed near Boulia western Queensland, Australia. This represents oldest ankylosaurian material predating holotype Kunbarrasaurus ieversi , was found overlying Allaru Mudstone. The encased limestone concretion maxillary tooth rows preserved only as impressions. Synchrotron radiation X-ray tomography used non-destructively image and reconstruct specimen 3D facilitate virtual preparation separate cranial bones. reconstruction revealed vomer, palatines, sections ectopterygoids maxillae, multiple teeth. palate posteriorly positioned choanae that differs more anterior placement seen other ankylosaurians, shared K. Akainacephalus johnsoni Cedarpelta bilbeyhallorum, Gobisaurus domoculus, Panoplosaurus mirus . Phylogenetic analyses place new within recently named basal clade Parankylosauria together ieversi. result, anatomical similarities K permits referral cf. sp. elucidates palatal anatomy ankylosaurs highlights one ubiquitous components faunas.