○ Order Ornithischians
↝ Lacked teeth in front of mouth
↝ Herbivorous
↝ Range of shape and sizes
↝ Subdivided into 5 distinct sub-orders
○ Sub-orders
↝ Anklyosauria
↪ “Fused lizard”
↪ Strong rigid body
↪ Clubbed tails
↪ Jurassic to Cretaceous
↝ Ceratopsians
↪ Beaks with grinding teeth toward back of mouth
↪ Most had bony frills/horns
↪ Jurassic to Late Cretaceous
↝ Pachycephalosaurs
↪ “Bone-head” — thick skull
↪ Late Cretaceous
↝ Ornithopods
↪ Well-developed forearms
↪ Diverse, mostly bipedal
↪ Ex. Edmontosaurus
↝ Stegosauria
↪ Related to Ankylosaurs
↪ Quadrupedal
↪ Tiny little walnut brains
↪ Thagomizer— spiked tail
↝ * * Theropods * *
○ Largest dinosaur ever— may be the Amphicoelias fragillimus, might be a diplodocus though
○ Order Saurischia
↝ Sauropods
↪ Largest vertebrates ever to walk the planet
↪ Long necks and tails
↪ Evolved from bipedal ancestors
↪ Migratory lifestyle
↝ Diplodocus
↪ Over 100 ft long
↪ Tail used as a whip
↪ Late Triassic to Cretaceous
↝ Apatosaurus
↪ Aka “brontosaurus”