Dinosaur Classification and Evolutionary Context

A set of vocabulary flashcards defining the major orders, subgroups, and evolutionary background of dinosaurs as described in the lecture notes.

Saurischia

A major order of dinosaurs, known as lizard-hipped, characterized by a pelvis structure where the pubis points downward and forward.

Ornithischia

A major order of dinosaurs, known as bird-hipped, characterized by a pelvis where the pubis points backward, though birds did not evolve from this group.

Theropoda

A subgroup of Saurischia consisting of mostly bipedal carnivores, such as Tyrannosaurus rex and Allosaurus, which are the ancestors of modern birds.

Sauropodomorpha

A subgroup of Saurischia consisting of large, long-necked herbivores, such as Brachiosaurus and Diplodocus, known for their massive size and long tails.

Thyreophora

A subgroup of Ornithischia consisting of armored dinosaurs, such as Stegosaurus and Ankylosaurus, featuring plates or bony armor for defense.

Ornithopoda

A subgroup of Ornithischia consisting of bipedal (two-legged) or facultatively quadrupedal (four legged) herbivores, including Iguanodon and duck-billed dinosaurs (Hadrosauridae).

Marginocephalia

A subgroup of Ornithischia consisting of dinosaurs with skull ornamentation, including ceratopsians like Triceratops and pachycephalosaurs with thick domed skulls.

Dinosauria

The clade to which all dinosaurs belong, which is part of the larger group Archosauria.

Archosauria

The larger group that includes dinosaurs, birds, and crocodiles.

Late Triassic

The geological period, around $230$ million years ago, when dinosaurs first appeared in the fossil record.

Modern Birds

_______ are considered living dinosaurs that are specifically derived from theropod saurischians.