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Today – 3/22

Today – 3/22. Critter in the news – ceratopsians More Coelurosauria Utah therizinid. Proposed functions of ceratopsian frills and horns. Defense against predators Species recognition Sexual selection – to attract the opposite sex (display) and/or male-male competition

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Today – 3/22

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  1. Today – 3/22 • Critter in the news – ceratopsians • More Coelurosauria • Utah therizinid

  2. Proposed functions of ceratopsian frills and horns • Defense against predators • Species recognition • Sexual selection – to attract the opposite sex (display) and/or male-male competition • Big area for attachment of large muscles for super-powerful jaws

  3. Horns of the young Triceratops

  4. Adult → Child → Skull of the child is 6-7 times smaller, different shape, but rudimentary horns and frill are present

  5. Frill and horns summary • Puncture wounds in frills of at least five groups of ceratopsians suggest male-male competition • Good evidence for sexual dimorphism and late development of frill in Protoceratops suggests a display function • Muscle attachment sites suggests powerful jaws • Young Triceratops skull suggests some non-sexual selection function like species recognition • Does this rule out use as predator defense?

  6. Administration • Test Tuesday! • Review session Monday, 5-?, Chem 134 • Ross OH delayed by 30 min today

  7. Last time • Theropod tree • Ceratopsian tree – Psittacosaurus, Protoceratops, chasmosaurines (Triceratops) with brow horns, centrosaurines (Styracosaurus) with fancy frills • End-Triassic extinction • Spinosaurus • Coelurosauria • Compsognathus

  8. Sinosauropteryx Nature

  9. Sinosauropteryx – “Chinese lizard feather” • 4 ft long, 1 ft tall at hips, 5.5 lbs, 64 tail vertebrae – tail nearly 2X longer than snout-vent!, feathers!, short arms, lizard for dinner, two eggs, close relative of Compsognathus, ~130 Ma • Jehol biota – same lake deposits as Dilong, along with algae, plant, pollen, fresh water invertebrates including shrimp, insects, clams, snails, fish, turtles, lizards, pterosaurs, crocs, mammals, and many birds

  10. Woolly rhinoceros went extinct 10,000 years ago

  11. www.dinosoria.com www.greatsouth.net Dromaeosauridae www005.upp.so-net.ne.jp/JurassicGallery www.baystatereplicas.com

  12. Dromaeosauridae – “swift lizard” • Utahraptor – 24 ft long, 15” in killing claw!, 1100 lbs, 125 Ma, found in braided stream deposits, sediments coming off of mountains to the west • Deinonychus – 10 ft long, 5 ft tall, 175 lbs, 100 Ma, the “Velociraptor” of JP, evidence of pack-hunting – 4 Deinos with big iguanodontid • Velociraptor – 6 ft long, 3 ft tall, 30 lbs, 80 Ma, wishbones!, “fighting dinosaurs”!, very birdlike, Djadokhta Fm, “smarter than a chimp?”, binocular vision, cuckoo behavior? • Stiff tails – dynamic stabilizers

  13. www.dino-nakasato.org

  14. www.trekearth.com Djadokhta Formation at Flaming Cliffs, Mongolia

  15. Djadokhta Formation • Semi-arid to arid from sandstones with cross-bedding characteristic of dunes, caliche • Rift valley formed by tectonic movement • Dinosaurs, eggs, embryos, babies, kids! • Theropods, sauropods, armored, duckbill, ceratopsian (23 in one day!), domeheads • Many closely related to W NA dinos • Also crocodiles, lizards, and mammals

  16. Hound from Hell!

  17. As smart as chimps? • Compare animal EQ’s – encephalization quotient • EQ = brain mass / body mass • Use endocranial volume / body volume with fossils – what problems do you see with this? Velociraptor was as smart as an ostrich, not a chimp

  18. Who was the smartest dinosaur?

  19. Troodon!

  20. Troodon – “wounding tooth” • 9 ft long, 3 ft tall at hips, 110 lb, 75 Ma NA, most common dinosaur tooth in Alaska • Smartest dinosaur, big eyes (nocturnal), stereoscopic vision, CT-scan of braincase – excellent hearing, opposable “thumb” • Close relative of the dromeosaurs (had mean killing toe, also) • Diet – duckbill babies and eggs, insects, plants (?), nocturnal mammals • Probably social – four found together

  21. Nature

  22. Troodon nesting behavior • Built nest, laid eggs in pairs half-buried • Laid one pair of eggs a day, maybe longer • Once all 20-24 eggs laid, mom tucked the tops of the eggs together and brooded them (mom found on a nest). What does brooding say about thermoregulation in these dinosaurs? • Babies born ready to go as evidenced by well-ossified embryos, untrampled hatched eggs; these are called “precocial” babies • Colonial nesting grounds – nests spaced 8-10 feet apart, length of parent (like modern colonially-nesting birds)

  23. Mononykus – one-fingered freaky big chicken dinosaur

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