A team of paleontologists has found in the south of the State of Utah (USA), the remains of a new species and genus of ankylosaurus, a dinosaur with a curious pointed bone armor, which has been baptized as Akainacephalus johnsoni . Its evolutionary origins are written all over its surface.
The bony protrusions that cover the head and snout of Akainacephalus johnsoni are similar to those of Asian ankylosaurs, according to experts in the journal PeerJ , which publishes the study.
It was a surprise, says Jelle Wiersma, a paleontologist at James Cook University in Townsville, Australia. She and Randall Irmis, a paleontologist at the Utah Museum of Natural History in Salt Lake City, expected the 76-million-year-old skeleton , unearthed in 2008 in Utah’s Grand Staircase-Escalante National Monument (a protected area in southern Utah that millions of years ago was part of a continent that no longer exists, Laramidia) had a softer structure, in the style of North American Ankylosaurs.
These armored dinosaurs first appeared in Asia about 125 million years ago and reached western North America about 77 million years ago. Another known North American ankylosaur, a different species found in New Mexico that is 3 million years younger than the newly discovered dinosaur, also has tough armor comparable to that of Akainacephalus.
New light on the evolution of the species
The new finding adds to evidence that at least two types of ankylosaurs migrated from Asia to North America in the late Cretaceous, possibly via a land bridge between continents, the researchers report: the Beringia Land Bridge , which allowed dinosaurs and other animals to move between Asia and North America.
Thus, after the decrease in sea level, the dinosaurs were able to reach the orchard in which they later lived. Probably, according to the researchers, the ankylosaurs dispersed from Asia to Laramidia several times, forming different populations in the north and south.
“It is always exciting to name a new fossil taxon, but it is equally exciting if that taxon also provides additional information about the big picture of its life , such as its diet or aspects of its behavior, and the environment in which it lived,” says Wiersma.
Akainacephalus, a herbivorous dinosaur, could measure up to five meters long and represents the most complete skeleton of an ankylosaurus dinosaur found in the southwestern United States: not only a complete skull has been discovered, but also much of the spine and a full rump, various fore and hind limb elements, and bony body armor including two neck rings and spiked armor plates.
Referencia: J.P. Wiersma and R.B. Irmis. A new southern Laramidian ankylosaurid, Akainacephalus johnsoni gen. et sp. nov., from the upper Campanian Kaiparowits Formation of southern Utah, U.S.A. Peer J. Published online July 19, 2018. doi:10.7717/peerj.5016.
Crédito imagen: Andrey Atuchin and the Denver Museum of Nature & Science
