article: Ornithischia
links: Stegosaur Origin of birds Upper Triassic Fabrosauridae Cretaceous Gymnosperms Sauropsid Mesozoic Animal Thyreophora Cerapoda Jurassic Chordate Seed fern Algae Oxford University Heterodontosaur Angiosperms Pteridospermatophyta Conifer Saurischia Ankylosaur Upper Cretaceous Dinosaur