EARTH 7 Lecture Notes - Lecture 12: Tetanurae, Theropoda, Horned Lizard
11/9/17
● Theropods
○ Predominantly meat eaters
● Theropod novelties
○ Knife-life teeth
■ Flat
■ Recurved
■ Serrated
○ Hollow bones
■ Lighter construction for more efficient running.
■ This would eventually come in handy for flight
○ Fused clavicles (=collar bone); aka: “wishbone”
○ Serrations on teeth
● Birds are theropods
1. Knife-like teeth
a. Lost in living birds (but present in early birds)
2. Hollow bones
a. present
3. Fused clavicles
a. Present
● Herrerasaurus - 230 MA, Argentina
○ Among the oldest dinosaurs known from fairly complete material
○ Small (2-3 meters long)
○ Bipedal
● “Early theropods” - 230 MA (mid triassic) Argentina
○Coelophysis - 216 MA, late triassic, New Mexico
○ Fossil footprints show that southern africa hosted some huge theropods early in
the jurassic (200 MA)
● Ceratosaurians (jurassic and cretaceous)
○ “Horned lizard”
○ Ceratosaurus (and brachiosaurus) both late jurassic
● Tetanurans novelties
1. Stiff tails
a. Fins on posterior process
b. Good counter balance for running
c. Tetanuran tail
i. “Raptor tail”
2. 3-digit hands
3. Complex branching air sacks
a. Birds use for unidirectional breathing
● Birds are tetanurans
1. Stiff tails
Document Summary
This would eventually come in handy for flight. Birds are theropods: knife-like teeth, lost in living birds (but present in early birds, hollow bones, present, fused clavicles, present. Among the oldest dinosaurs known from fairly complete material. Early theropods - 230 ma (mid triassic) argentina. Coelophysis - 216 ma, late triassic, new mexico. Fossil footprints show that southern africa hosted some huge theropods early in the jurassic (200 ma) Tetanurans novelties: stiff tails, fins on posterior process, good counter balance for running, tetanuran tail i. Raptor tail : 3-digit hands, complex branching air sacks, birds use for unidirectional breathing. Birds are tetanurans: stiff tails, present (but highly reduced, 3-digit hands, present (fused, complex branching air sacks, present. First description of a dinosaur 1824: megalosaurus, a giant extinct. He based this on only a few partial specimens at his disposal at the time. New evidence suggests it was actually semi-aquatic, with limited mobility on land (think crocodile)
