Ceratopsia or
Ceratopia ( or ;
Greek: "horned faces") is a group of
herbivorous, beaked
dinosaurs that thrived in what are now
North America,
Europe, and
Asia, during the
Cretaceous Period, although ancestral forms lived earlier, in the
Jurassic. The earliest known ceratopsian,
Yinlong downsi, lived between 161.2 and 155.7 million years ago. The last ceratopsian species,
Triceratops prorsus, became extinct during the
Cretaceous–Paleogene extinction event, .