Sauropod Gigantism

摘要

Sauropod dinosaurs were the largest animals ever to inhabit the land (see the figure). At estimated maximum body masses of 50 to 80 metric tons, they surpassed the largest terrestrial mammals and nonsauro-pod dinosaurs by an order of magnitude. With body lengths of more than 40 m and heights of more than 17 m, their linear dimensions also remain unique in the animal kingdom. From their beginnings in the Late Triassic (about 210 million years ago), sauropods diversified into about 120 known genera. They dominated ecosystems for more than 100 million years from the Middle Jurassic to the end of the Cretaceous, setting a record that mammalian herbivores will only match if they can double their current geological survival time. Thus, sauropods were not only gigantic but also, in evolutionary terms, very successful. Recent advances bring us closer to understanding the enigma of their gigantism (1-3).