Teratophoneus

Teratophoneus is a genus of carnivorous tyrannosaurid theropod dinosaur which lived during the late Cretaceous period (late Campanian age, about 77 to 76 million years ago) in what is now Utah, USA. It is known from an incomplete skull and postcranial skeleton recovered from the Kaiparowits Formation. Teratophoneus was named by Thomas D. Carr, Thomas E. Williamson, Brooks B. Britt and Ken Stadtman in 2011 and the type species is T. curriei. The generic name is derived from Greek teras, "monster", and phoneus, "murderer". The specific name honors Philip J. Currie.

Description
The holotype of Teratophoneus consists of a fragmentary skull and parts of the postcranial skeleton. The fossils were originally assigned to four different individuals, but are probably only of a single subadult animal. The specimen of Teratophoneus was not fully grown, according to an estimate by Carr et al. was about 6 metres (20 ft) in length and 667 kg in weight.[1]

Compared to the skull of an Albertosaurus, Teratophoneus is roughly twenty-three percent shorter in proportion between the lacrimal bone of the orbital fenestra and the tip of the snout. The skull of Teratophoneus is also comparably deeper. It is unclear if there was a specific reason for these differences, but the extra depth may have allowed for stronger jaw muscles, increasing the bite force of Teratophoneus.

Discovery and naming
Fossils of Teratophoneus were first found in the Kaiparowits Formation of southern Utah. Later, fossils from the same formation were discovered and identified as the genus. Argon-argon radiometric dating indicates that the Kaiparowits Formation was deposited between 76.1 and 74.0 million years ago, during the Campanian stage of the Late Cretaceous period. This date means that Teratophoneus lived in the middle of the Campanian stage of the Late Cretaceous. Three different fossils of Teratophoneus have been found. Originally, Teratophoneus was described based on the holotype UMNH VP 16690. More recently, the specimens UMNP VP 16691 and BYU 8120 have been assigned to it.[3]

Teratophoneus was named by Thomas D. Carr, Thomas E. Williamson, Brooks B. Britt and Ken Stadtman in 2011. The type and only species was named T. curriei. The generic name is derived from the Greek teras, "monster", and phoneus, "murderer".[4] The specific name honors Philip J. Currie.