Sauropodomorphs

THE SAUROPODOMORPHA ("lizard-feet forms.")

were herbivorous, usually quadrupedal (four-footed)

dinosaurs. A clade within Saurischia, they were 

characterized by small heads, bulky bodies, and

long necks and tails. Sauropodomorphs have

often been split into two groups: prosauropods

and sauropods. Prosauropods lived from Late

Triassic to Early Jurassic times (225-180 million years ago) and

included beats such as the small Anchisaurus and one of the first

very large dinosaurs, Plateosaurus. By Middle Jurassic times (about

165 million years ago), sauropods had replaced prosauropods and

spread worldwide. They included the heaviest and longest land animals

ever, such as Diplodocus and Brachiosaurus. 

Brachiosaurus

Sauropods persisted to the 

end of the Cretaceous period (65 million years ago). Many of these

huge bulk and powerful tails, which they could use to lash out at

attackers. Sauropodomorphs were the most common large

herbivores until Late Jurassic times (about 145 million years ago),

and appear to have survived in both southern and

northern continents until the end of the Cretaceous period.