Today – 3/20 Critter in the news – Albertaceratops Spinosaurus End-Triassic extinction Coelurosauria Dr. Mary Schweitzer

Administration Test one week from today! Review session Monday, 5-6:30, right here 1-pt XC for MFM by end of March

Styracosaurus - a centrosaurine Triceratops - a chasmosaurine Two types of ceratopsid

Albertaceratops Nesmoi

Possible test question The common ancestor of the chasmosaurs and the centrosaurs probably had: a) a fancy frill b) large brow horns c) both a fancy frill and brow horns d) sharp, dagger-like teeth

Albertaceratops - horned dino Late Cretaceous, 78 Ma 20 feet long,.5 tons, quadrupedal herbivore Chasmosaurine ceratopsians typically had plain frills and large brow horns Centrosaurine ceratopsians typically had fancy frills and small or no brow horns Albertaceratops was a chasmosaurine with large brow horns! Albertaceratops nesmoi was named after a local rancher who supports paleontology

Last time Allosauroidae - Allosaurus, Acrocanthosaurus, Carcharodontosaurus, Giganotosaurus

Spinosaurus!

Clade Spinosaurus Middle Cretaceous, 95 Ma, 3 fingers 50+ feet long, 9 tons, 6 foot sail on back possibly for thermoregulation and display - biggest theropod so far! Crododile-like lower jaw – fish-eater? Same Bahariya Formation as Carcharodontosaurus

End-Triassic extinction

The Earth Through Time image gallery (Wiley) Marine genera through time

Proposed causes of TJ extinction There wasn’t one – fossil record artifact Sea level fluctuation Asteroid strike! Rifting of Pangea Climate change

Sea level through time

landsat.us.gov

Central Atlantic Magmatic Province

End-Triassic important points Fern and iridium spike indicate some sort of impact, but the causes of this event are very poorly understood This event eliminated the incumbent large terrestrial vertebrates (like Postosuchus and Placerias), paving the way for the evolution of the giant dinosaurs of the Jurassic and Cretaceous

Clade Coelurosauria D:TT

Clade Coelurosauria Very diverse clade – diet, reproduction, size, lifestyle, morphology United by undeniable ~20 shared derived characters like the ankle Unusually limited geographic distribution – most are known from Asia and western NA Mostly Cretaceous Three or less fingers Includes Archaeopteryx and birds!

Clade Compsognathus

Compsognathus – “elegant jaw” Early Coelurosaur, Late Jurassic, 145 Ma 3 ft long, 10” high at the hips, 10 lbs, mostly tail and neck, pointy skull 3” long 2 specimens, a juvenile from the Solenhofen ls and an adult from France Juvenile’s stomach content – Bavarisaurus, a fast little lizard. Compy fast, agile hunter ~30 immature eggs found with juvenile Skeleton very similar to Archaeopteryx

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 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

Woolly rhinoceros went extinct 10,000 years ago