Machairoceratops
Machairoceratops (meaning "bent sword horned face") is an extinct genus of centrosaurine ceratopsian dinosaur known from the Late Cretaceous Wahweap Formation (late Campanian stage) of Grand Staircase-Escalante National Monument, southern Utah, United States. Discovery. It contains a single species, "M. cronusi", first described and named in 2016 by Eric K. Lund, Patrick M. O’Connor, Mark A. Loewen and Zubair A. Jinnah. The generic name is derived from Greek "machairis", meaning "bent sword", in reference to its unique frill ornamentation showing two forward curving horns on the frill's uppermost part, and Latinized Greek "ceratops", meaning "horned-face", which  is a common suffix for ceratopsian genera names. The specific name "cronusi" refers to Cronus, a Greek god who deposed his father Uranus by castrating him with a sickle or scythe based on the mythology, and as such is shown carrying a curved bladed weapon. "Machairoceratops" is known solely from the holotype UMNH VP 20550, found in 2006, which is housed at the Natural History Museum of Utah. It is represented by a partial skull including two curved and elongate eyesocket horncores, the left jugal bone, a nearly complete but slightly deformed braincase, the left squamosal bone, and a parietal  bone complex and its unique horn ornamentation, all collected in association. Phylogeny. Lund "et al." (2016) tested the position of "Machairoceratops" within Centrosaurinae by performing maximum parsimony and Bayesian phylogenetic species level analyses. The maximum parsimony analysis yielded a large polytomy at the base of Centrosaurinae, with only Centrosaurini, most of Pachyrhinosaurini ("Einiosaurus", "Wendiceratops" and Pachyrostra), and a clade formed by "Avaceratops" and "Nasutoceratops" being resolved. The Bayesian analysis yielded a fully resolved topology which is shown below. The cladogram presented below follows a more recent phylogenetic analysis by Chiba "et al." (2017):