Ceratopsidae

Ceratopsidae (sometimes spelled Ceratopidae) is a family of ceratopsian dinosaurs including Triceratops, Centrosaurus, and Styracosaurus. All known species were quadrupedal herbivores from the Upper Cretaceous. All but one species are known from western North America, which formed the island continent of Laramidia during most of the Late Cretaceous. Ceratopsids are characterized by beaks, rows of shearing teeth in the back of the jaw, elaborate nasal horns, and a thin parietal-squamosal shelf that extends back and up into a frill. The group is divided into two subfamilies—Chasmosaurinae and Ce

Ceratops (meaning ) is a dubious genus of herbivorous ceratopsian dinosaur which lived during the Late Cretaceous. Its fossils have been found in the Judith River Formation in Montana. Although poorly known, Ceratops is important in the history of dinosaurs, since it is the type genus for which both the Ceratopsia and the Ceratopsidae have been named.

Dysganus (dis-GANN-us) (meaning "rough enamel") is a dubious genus of ceratopsian dinosaur from the Campanian stage of the Late Cretaceous. The fossil teeth referred to Dysganus were first collected by Charles Sternberg from the Judith River Formation of Montana and later described by Edward Drinker Cope. All of the species are now seen as dubious ceratopsians, though referred material from tyrannosaurids and hadrosaurids were found in New Mexico.

Polyonax (meaning "master over many") is a genus of ceratopsid dinosaur from the Late Cretaceous (late Maastrichtian) Denver Formation of Colorado, United States. Founded upon poor remains, it is today regarded as a dubious name.