analysis is reproduced below. The unique, roughened protrusion of the squamosal of Yehuecauhceratops is only otherwise seen among centrosaurines in Menefeeceratops from the much earlier Menefee Formation of New Mexico, and Crittendenceratops, from the likewise earlier Fort Crittenden Formation of Arizona. However, since these specimens are separated in time by more than one million years, it is unlikely that they belong to the same genus. Additionally, the specimen UMNH VP16704, referred to as the "Nipple Butte skull", also resembles Yehuecauhceratops and Menefeeceratops in having a fan-shaped end of the squamosal, though it lacks this singular protrusion. Paleoecology The environment Yehuecauhceratops lived in, corresponding to the lower part of the upper Aguja Formation, would have been a freshwater-to-brackish coastal marsh and floodplain that were part of a river delta. Sediments also record the presence of oxbow lakes and some coastal marine deposits. Although the Mexican strata of the Aguja Formation have not been solidly dated, dating of other deposits belonging to the Aguja and the contemporary Cerro del Pueblo Formations has produced date ranges that overlap around 72.5 Ma. In Mexico, the diversity of animals in the Aguja Formation is somewhat limited. Asides from Yehuecauhceratops, other discovered remains include the chasmosaurine Agujaceratops mavericus, pachycephalosaur teeth; large tibiae from hadrosaurids; crocodilian teeth; and shell fragments from baenid and trionychid turtles. From contemporaneous deposits of the Aguja Formation in Texas, numerous dinosaurs are known; they include the chasmosaurine Agujaceratops mariscalensis, the saurolophine Kritosaurus, the pachycephalosaur Texacephale, and the tooth taxon Richardoestesia, as well as unnamed lambeosaurines, nodosaurs, tyrannosaurs, ornithomimids, caenagnathids, and dromaeosaurs. Non-dinosaurs include the giant alligatoroid Deinosuchus and a goniopholidid; the squamates Odaxosaurus, Proxestops, Restes, Sauriscus, and various unnamed taxa; the turtles "Baena" and "Aspideretes", as well as an additional chelonian; the amphibians Albanerpeton, a scapherpetonid, a salamander, and a frog; the mammals Cimolomys, Meniscoessus, Cimolodon, Alphadon, Turgidodon, Pediomys, Gallolestes, and others; various bony fish; and the cartilaginous fish Hybodus, Lissodus, Scapanorhynchys, Onchopristis, Ischyrhiza, Squatirhina, Ptychotrygon, and others. Although ceratopsids are very common in Laramidian deposits north of Colorado, there are very few of them from the south, and even fewer of them actually preserve any diagnostic material. Centrosaurines, despite their limited material, appeared to have been somewhat more common in the south. However, several chasmosaurines are also known from Mexico, namely Agujaceratops mavericus and Coahuilaceratops magnacuerna (from the Cerro de Pueblo Formation). This is consistent with a likely climate-related separation of