Chasmosaurus belli

Chasmosaurus is the eponymous member of the chasmosaurine (long-frilled) ceratopsids, which included its famous bigger cousin, Triceratops. Living during the Late Cretaceous in Alberta, Canada, Chasmosaurus is recognizable for its very large frill pierced by two enormous openings. It also has fairly reduced brow horns, demonstrating that brow horn length is not a good proxy for which group of ceratopsids a horned dinosaur comes from.