How was the triceratops classified?

Triceratops belonged to the family Ceratopsidae, which also included dinosaurs such as Pachyrhinosaurus, Styracosaurus, and Chasmosaurus. Taxonomically speaking, all dinosaurs belonged to the class Reptilia and the clade Dinosauria.

Triceratops' taxonomy proceeds as follows:

• Domain: Eukaryote
• Kingdom: Animalia
• Phylum: Chordata
• Class: Reptilia
• -Sub-class: Dinosauria
• Order: Ornithischia
• Family: Ceratopsidae
• Genus: Triceratops
• Species: T. horridus