1. Today – 4/12 Critter on the T-shirt Ornithischia Pterosaurs, marine reptiles, crocodiles Geodaze

3. Last time Evolutionary convergence Sauropodomorpha – Prosauropoda (Plateosaurus) and Sauropoda (Apatosaurus, Brachiosaurus, and Alamosaurus). Lifestyles and social behavior Sauropod nesting grounds in Argentina

4. Test 4/24 Review 4/23, 5:45-7, right here 15% from ch. 8-14 of BotF

5. Clade Ornithischia

6. Pisanosaurus – oldest known ornithischian 228 Ma – Ischigualasto Formation

7. Clade Ornithischia Shared evolutionary novelties include pelvic structure, ossified tendons on the vertebral column, and the predentary bone Ancestral ornithischian – Pisanosaurus, 228 Ma form the same Ischigualasto Formation as Eoraptor and Herrerasaurus Contains three clades: Thyreophora, Ornithopoda, and Marginocephalia

8. Scutellosaurus – ancestral thyreophoran, 200 Ma in N AZ

12. Clade Thyreophora Healthy animals, from 200 Ma up to the end No egg fossils, few tracks, mostly isolated individuals except for groups of juvenile ankylosaurs from China so no evidence for social behavior except maybe for herding of young, quadrupedal low-grazing herbivores Scutellosaurus – 200 Ma N AZ, 4 ft long, 18” tall at hips, 22 lbs, ancestral thyreophoran

13. More Thyreophora “Armored dinosaurs”, up to 30 feet long, 4.5 tons, scissoring side spikes, osteoderms, two clades – ankylosaurs (tail clubs), nodosaurs (no tail clubs) Stegosauria – two rows of alternating plates or spikes running down back, four tail spikes. Thermoregulation, defense, species recognition? Mainly Jurassic, but held on to the end, no “second brain”, up to 30 feet long, 3 tons

20. Duckbill jaws

21. Clade Ornithopoda Early Jurassic to the end, chewers, some signs of diseases and healed wounds Iguanodon – 130 Ma, lots of trackways: slow! and social, 30 ft long, 16 ft tall, 4.5 tons, thumb spike, bipedal Duckbills – late Cretaceous, big: up to 40 feet long, two clades – hadrosaurs (no head crest, dewlap) and lambeosaurs (head crests for display and sound, sexual dimorphism)

22. More duckbills On the menu for tyrannosaurs – Edmontosaurus found with healed bite in vertebra, another with tyrannosaur tooth embedded in healed rib! Found in coprolites. Maiasaura – colonial nesting grounds, nests evenly spaced about 22 feet apart (size of an adult), site fidelity, 10-footers still in nest!, grew fast, herd of 10,000 killed in Montana volcanic eruption

23. Dome-headed dinosaur, or pachycephalosaur

25. Triceratops

27. Clade Marginocephalia Cretaceous only, two clades, only found in NA, Asia, and Europe Dome-headed dinosaurs – skulls up to 10 in thick!, display (?) head-butting (?) ramming (?) defense (?), poor fossil record, 25 ft long, 1.5 tons Horned-dinosaurs (ceratopsians) – 27 feet long, 8 tons, up to 10 foot long skulls!, intraspecific combat, many bone beds (social), pathologies related to weight (torn tendons, stress fractures)

29. Deinosuchus – alligator of death, 40 (?) feet long