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

Today – 3/20Today – 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 frillb) large brow hornsc) both a fancy frill and brow hornsd) sharp, dagger-like teeth

Albertaceratops - horned dinoLate 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

www.twoguysfossils.com www.paleoworld.com

Last time

Allosauroidae - Allosaurus, Acrocanthosaurus, Carcharodontosaurus, Giganotosaurus

Spinosaurus!

Clade SpinosaurusMiddle 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

www.twoguysfossils.com www.paleoworld.com

End-Triassic extinctionhttp://rockbox.rutgers.edu/103web

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

www.dinoland.dk

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!

www.dinoruss.org

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 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