A prosauropod is a large, herbivorous, quadrupedal dinosaur that flourished during the Late Triassic and Early Jurassic periods. The name prosauropod comes from the Greek words for “early lizard” or “before lizard”. Prosauropods were characterized by their long necks, small heads, and large bodies; they were some of the largest land animals of their time. They ranged in size from 2 to 18 meters (6.5 to 59 feet) long and weighed up to 10 metric tons (11 short tons).
The first prosauropods appeared in the Late Triassic period, about 230 million years ago. They quickly became the dominant herbivores of their time and remained so for more than 100 million years, until they were replaced by sauropods in the Middle Jurassic period. Although most prosauropods went extinct at the end of the Triassic period, a few species persisted into the Early Jurassic period before going extinct.
Prosauropods were closely related to sauropods—the two groups shared many similarities, such as long necks and tails, four-legged locomotion, and toothless beaks. However, there are several key differences between these two groups of dinosaurs. For example, prosauropods had smaller bodies than sauropods and their necks were proportionately shorter relative to their body size; they also lacked some of the distinctive features that characterize sauropods (such as air sacs). In addition, unlike sauropods, which evolved in isolation on different continents, prosauropods originated and thrived in close proximity to early crocodilians—a fact that may have influenced their evolution (for example by driving them towards an herbivorous diet).