Menefeeceratops is an extinct genus of centrosaurine ceratopsian that lived New Mexico during the Late Cretaceous.
Description[]
Menefeeceratops is known from the Allison Member, Menefee Formation of the Campanian. The holotype was described 1997, new fossils reinterpret the evidence found by previous authors, finding a new taxon, representing the oldest centrosaurine. It was named by Sebastian Dalmon and Peter Dodson et al.. The specimen contains a partial left premaxilla, a near-complete left postorbital horncore, a fragmented parietal, both squamosals, the left jugal, predentary and left dentary, 2 cervical, eight dorsal, vertebrae, a partial sacrum, six sacral vertebrae, 11 dorsal ribs, a distal left radius, the proximal and distal portions of the ulna, the left femur and the left metatarsal II. The lack of epiossified lateroposterior parietal (shared with Machairoceratops), three epiossified segments in the squamosal and three smaller secondary undulations of the episquamosal locus S1 distinguishes the genus. Additionally: two subequal embayments in the posterior-free margin of the squamosal, with the more dorsal one between episquamosal loci 1 and 2 and larger than the lateroventral one between 2 and 3. Three ridges exist in the dorsolateral surface of the squamosal, with an elongate and posterior portion, a shallow and distinct groove in the medial surface of the squamosal. Such a feature parallels the ventrolateral and ventroposterior edges. The horns curve arterially distally, with two elongate ridges at the lateral dentary and diverges anteriorly to form a triangular fossa. It estimated to be 4 meters (13 feet) long, by comparing it with relatives[1][2][3].
Classification[]
Credit: @fishboy86164577 on Twitter.
Phylogeny places Menefeeceratops close to Crittendenceratops. This adds insight to the individual variation in genera, and the temporal and/or paleobiographic distribution of centrosaurines in Late Cretaceous Laramidia. If this genus is the earliest centrosaur, it would indicate the group evolved in southern and western North America, specifically the Rocky Mountain area, radiating north in the Upper Middle/Late Campanian. It is also closely related with Yehuecauhceratops[4][5].
References[]