Theropods
What subgroup of theropods is characterized by a sickle-shaped claw on the second toe?
Dromaeosaurids
What are the air-filled cavities in sauropod vertebrae called, and what was their purpose?
Pneumatic cavities - this reduces dinosaur's overall weight
What are the two subgroups of Thyreophora and one example species from each?
Stegosaurs - e.g. Stegosaurus; Ankylosaurs - e.g. Ankylosaurus
What feature unique to ceratopsians likely served both display and species recognition purposes?
The bony neck frill
What two major groups make up Saurischia?
Sauropodomorpha and Theropoda
What unique features of Spinosaurus suggest it was semi-aquatic?
Dense, solid bones for buoyancy, crocodile-like snout, high nostrils on the skull
How did peg-shaped teeth vs spatula-shaped teeth in different sauropods suggest feeding habits?
Spatula teeth like Brachiosaurus cropped high vegetation
Peg teeth like Diplodocus raked leaves from branches
What is the leading scientific theory for the function of Stegosaurus's back plates?
Thermoregulation and/or display - the plates had blood vessels suggesting heat exchange
How did the hollow crests of hadrosaurs like Parasaurolophus likely function?
As resonating chambers to produce calls for communication within the herd
What fossil evidence confirms that some saurischian theropods had feathers?
Fossilized feather impressions found on species like Sinosauropteryx and Velociraptor relatives in China
How did Ceratosaurs and Tetanurans differ in the number of functional fingers on their hands?
Tetanurans had three functional fingers; ceratosaurs had four
Titanosaurs were the last surviving sauropods. What unique feature set them apart from earlier sauropods?
Armored skin with bony osteoderms and wider, more splayed legs
How did Nodosaurids differ from ankylosaurids in their defensive features?
Nodosaurids lacked a tail club but had large shoulder spikes; ankylosaurids had the iconic bony tail club
What does the extremely thick domed skull of pachycephalosaurs suggest about their behavior?
Head-butting or flank-butting during competition for mates or territory
Why is it surprising that modern birds evolved from saurischians rather than ornithischians, despite being called "bird-hipped"?
Ornithischians have the backward-pointing pubis that looks like a bird's, yet birds actually descended from the "lizard-hipped" saurischian theropods