Akainacephalus: Research Database
Ankylosauridae (Ornithischia) · Late Cretaceous (~76 MYA) ·> North America — USA (Wahweap Formation, Utah)
Research Note: Akainacephalus was an ankylosaurid from the Late Cretaceous Wahweap Formation of Utah. As a member of Ankylosauridae, it provides important data on armored dinosaur diversity and evolution in the Late Cretaceous of North America.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
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Wiersma & Irmis 2018: Akainacephalus from the Wahweap Formation
Wiersma & Irmis 2018 provide the original description of Akainacephalus from the Late Cretaceous Wahweap Formation of Utah, establishing it as an ankylosaurid and documenting its significance for understanding ankylosaurid diversity in the Late Cretaceous of North America
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Confirmed | A | 2018 | Fossil | Wiersma & Irmis, PeerJ | Taxonomy |
|
Arbour & Burns 2014: Ankylosaurid diversity in the Cretaceous of North America
Arbour & Burns 2014 provide additional data on ankylosaurid diversity from the Cretaceous of North America, contextualising Akainacephalus within the broader evolutionary history of armored dinosaurs
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Confirmed | B | 2014 | Fossil | Arbour & Burns, PLoS ONE | Diversity |
Active Debate: Ankylosaurid Systematics in the Late Cretaceous of North America
Whether Akainacephalus represents a basal or derived ankylosaurid is debated.
What We Still Do Not Know About Akainacephalus
- Complete skeletal morphology: Partial specimen known.
- Body mass: Estimated.
- Skin and armor: Partially known.
- Social behavior: No direct evidence.
In Depth
Akainacephalus is a genus of ankylosaur that lived in North America during the late Cretaceous. During this time, the central portion of North America was submerged by the Western Interior Seaway, carving North America into two landmasses; Appalacia to the East, and Laramidia to the West. Akainacephalus hails from the southern portion of Laramidia, and at the time of the genus description, is the best preserved ankylosaur from this area. Akainacephalus however was not the first ankylosaur discovered in this region, another ankylosaur named Nodocephalosaurus is also known. Both of these two genera are noted for having similar skull structure, though the original describers are confident in Akainacephalus being a distinct genus after testing between known skull elements of Akainacephalus and Nodocephalosaurus.
Additionally, both Akainacephalus and Nodocephalosaurus have skulls that appear to be more similar to Asian ankylosaurid genera such as Tarchia and Saichania than to those seen in other North American ankylosaurid dinosaurs that are known from the Northern portion of Laramidia. This reinforces the idea of species radiations between Asia and North America, but then this has also been indicated elsewhere. Both Asia and North America had similar kinds of late Cretaceous dinosaurs as one another, with remains of hadrosaurs, ankylosaurs, dromaeosuars, tyrannosaurs, ceratopsians and ornithomimosaurs amongst others known from both continents during same time periods.
Further Reading
- A new southern Laramidian ankylosaurid, Akainacephalus johnsoni gen. et sp. nov., from the upper Campanian Kaiparowits Formation of southern Utah, USA. - PeerJ. 6: e5016. - Jelle P. Wiersma & Randall B. Irmis - 2018.
