23. Introducing the last of the large North American allosauroids for #TheSummerOfTheropods, #Siats. Art by Jorge Gonzales.

The theropod’s name is derived from the name “Siats”, a cannibalistic clown-monster from Ute mythology; imagine if #Pennywise was a theropod dinosaur. Art by HodariNundu

Containing only one discovered species, Siats is the first megaraptoran neovenatorid (a group of allosauroid theropods from Africa, Asia, Europe, and South America) to be discovered in North America, it should be noted that Siats and other megaraptorans may also be coelurosaurs.

Fossils of Siats were found in the early stages of the Late Cretaceous of the Cedar Mountain Formation of Utah.

The recovered bones include five dorsal and eight caudal vertebrae, a chevron, partial right ilium, ischium and fibula, a partial left tibia, and several right and left pedal phalanges.
Silhouette by DaCaTaraptor and diagram by Paleocolour

Siats represents one of the largest known theropods from North America with an estimated length of 39 feet and weighing roughly 4 tons. Silhouette by DaCaTaraptor and diagram by Paleocolour

It was also comparable in size to Saurophaganax, Acrocanthosaurus, and Tyrannosaurus despite the specimen being a skeletally immature individual. Image by Prehistoric Wildlife.

The discovery of Siats also reveals that allosauroids did not yield dominance in North America to tyrannosauroids until the late Cretaceous. Art by @studio252mya