Marginocephalia

The largest well-known dome-headed dinosaur, from the latest Cretaceous of the western United States. Adult skulls carry a massive rounded dome and a fringe of blunt nodes, but much of the body remains reconstructed from incomplete skeletons and close relatives.

The oldest definitive and most complete known pachycephalosaur, a sheepdog-sized Mongolian herbivore whose dome developed before its body finished growing.

A small, primarily bipedal Early Cretaceous ceratopsian from Mongolia with a deep skull, parrot-like beak, flared cheek bones and clusters of polished stones preserved inside some skeletons.

A sheep- to pig-sized, four-legged ceratopsian from Mongolia’s Late Cretaceous dune fields, known from abundant skulls and skeletons, a juvenile nest and the extraordinary ‘Fighting Dinosaurs’ fossil.

A large Canadian centrosaurine whose nose carried a broad roughened boss instead of a conventional horn, known from multiple partial skulls and regional bonebeds.

A short-frilled horned dinosaur from Alberta, famous for its long nasal horn, hooked frill ornaments and enormous mass-death bonebeds.