01:119:160 Lecture Notes - Lecture 3: Morrison Formation, Tyrannosauridae, Thagomizer

• School: Rutgers University
• Department: Biological Science
• Course: 01:119:160
• Professor: John Pescatore

Document Summary

Dermal bone armour, tail spikes, dorsal double row of spines or plates, numerous nodules of bone set in skin, ilia in pelvis, enlarged and flared over hind limbs, tail clubs, spikes on posterior corners of skull. Thyreophora - shield-bearers , included stegosaurus (plated reptile) and ankylosaurus (fused reptile), had dermal bone armour plates. Primitive members included scutellosaurus and scelidosaurus which had armour plates called scutes or osteoderms (skin bones that float on skin ) Scutes are made of bone but covered in living tissue, evolved as a primitive form of defense. Speed was not enough to protect thyreophorans, (ornithopods were faster and sauropods were larger), sacrifices speed for armour. Thyreophorans had to become obligatory quadrupedal (forelimbs significantly shorter than hindlimbs) Bodies low to the ground, therefore ate low vegetation. Stegosauria - plated lizards - small, long and pointy heads, slow moving, short, stout forelimbs, long hindlimbs, had hooves not claws, toothless beak, leaf-shaped teeth.