Today – 3/22Today – 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

Big area for attachment of large muscles for super-powerful jaws

Horns of the young Triceratops

Adult →

Child →

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

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?

Administration

Test Tuesday!

Review session Monday, 5-?, Chem 134

Ross OH delayed by 30 min today

Last time

Theropod tree

Ceratopsian tree – Psittacosaurus, Protoceratops, chasmosaurines (Triceratops) with brow horns, centrosaurines (Styracosaurus) with fancy frills

End-Triassic extinction

Spinosaurus

Coelurosauria

Compsognathus

Nature

Sinosauropteryx

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 MaJehol 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

Woolly rhinoceros went extinct 10,000

years ago

www.dinosoria.com

www005.upp.so-net.ne.jp/JurassicGallery

www.greatsouth.net

www.baystatereplicas.com

Dromaeosauridae

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

www.dino-nakasato.org

www.trekearth.com

Djadokhta Formation at Flaming Cliffs,

Mongolia

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

Hound from Hell!

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

Who was the smartest dinosaur?

Troodon!

Troodon – “wounding tooth”

9 ft long, 3 ft tall at hips, 110 lb, 75 Ma NA, most common dinosaur tooth in AlaskaSmartest 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 mammalsProbably social – four found together

Nature

Troodon nesting behaviorBuilt nest, laid eggs in pairs half-buriedLaid one pair of eggs a day, maybe longerOnce 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” babiesColonial nesting grounds – nests spaced 8-10 feet apart, length of parent (like modern colonially-nesting birds)

Mononykus – one-fingered freaky big chicken dinosaur