Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct
clade of long-necked,
herbivorous,
saurischian dinosaurs that includes the
sauropods and their ancestral relatives.
Sauropods generally grew to very large sizes, had long necks and tails, were
quadrupedal, and became the largest animals to ever walk the Earth. The "prosauropods", which preceded the sauropods, were smaller and were often able to walk on
two legs. The sauropodomorphs were the dominant terrestrial herbivores throughout much of the
Mesozoic Era, from their origins in the mid-
Triassic (approximately 230 Ma) until their decline and extinction at the end of the
Cretaceous (approximately 66 Ma).