Named By: Jelle P. Wiersma & Randall B. Irmis - 2018.
Classification: Chordata, Reptilia, Dinosauria, Ornithischia, Ankylosauridae, Ankylosaurini.
Species: A. johnsoni (type).
Size: Holotype roughly about 3.75 meters long.
Known locations: USA, Utah - Kaiparowits Formation.
Time period: Campanian of the Cretaceous.
Fossil representation: Skull and partial postcranial skeleton.
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
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
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.
- 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.