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