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

2022/03/28 by Timothy G. Frauenfelder, Phil R. Bell, Tom Brougham +5 · 1 citation
Earth and Planetary Sciences · Environmental Science · #Paleontology and Evolutionary Biology #Evolution and Paleontology Studies #Ichthyology and Marine Biology #Paleontology #Geology #Holotype #Cretaceous #Skull #Laurasia #Sauropoda #Theropoda #Anatomy #Gondwana #Biology #Structural basin #Taxonomy (biology) #Zoology

paper · pdf · doi:10.3389/feart.2022.803505

openalex publication_date 2022/03/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

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

Citations

• The Evolution of Dinosaurs
• Euoplocephalus tutus and the Diversity of Ankylosaurid Dinosaurs in the Late Cretaceous of Alberta, Canada, and Montana, USA
• Cretaceous marine reptiles of Australia: a review of taxonomy and distribution
• New isolated pterodactyloid bones from the Albian Toolebuc Formation (western Queensland, Australia) with comments on the Australian pterosaur fauna
• A Mid-Cretaceous Association of Shell Beds and Organic-rich Shale: Bivalve Exploitation of a Nutrient-Rich, Anoxic Sea-floor Environment
• A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation
• A probable ankylosaurian (Dinosauria, Thyreophora) from the Early Cretaceous of New South Wales, Australia
• Reappraisal of Mythunga camara Molnar & Thulborn, 2007 (Pterosauria, Pterodactyloidea, Anhangueria) from the upper Albian Toolebuc Formation of Queensland, Australia
• Revised geology, age, and vertebrate diversity of the dinosaur-bearing Griman Creek Formation (Cenomanian), Lightning Ridge, New South Wales, Australia
• Ornithopod diversity in the Griman Creek Formation (Cenomanian), New South Wales, Australia
• Palynological-age determination of Early Cretaceous vertebrate-bearing beds along the south Victorian coast of Australia, with implications for the spore-pollen biostratigraphy of the region
• Stratigraphic constraints on the Lower Cretaceous Orallo Formation, southeastern Queensland: U–Pb dating of bentonite and palynostratigraphy of associated strata
• New ankylosaurian trackways (cf. Tetrapodosaurus) from an uppermost Cretaceous level of the El Molino Formation of Bolivia
• Bizarre tail weaponry in a transitional ankylosaur from subantarctic Chile
• Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs
• The ankylosaurid dinosaurs of the Upper Cretaceous Baruungoyot and Nemegt formations of Mongolia

Cited by

• East Gondwana [wikipedia]

Related

• A probable ankylosaurian (Dinosauria, Thyreophora) from the Early Cretaceous of New South Wales, Australia
• New anhanguerian pterosaur remains from the Lower Cretaceous of Queensland, Australia
• Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs
• A new species of crested pterosaur (Pterodactyloidea, Anhangueridae) from the Lower Cretaceous (upper Albian) of Richmond, North West Queensland, Australia
• The ankylosaurid dinosaurs of the Upper Cretaceous Baruungoyot and Nemegt formations of Mongolia