About 200 million years ago, a feeding group of Plateosaurus watches as the dominant male of the group chases away a rival male.
In the accompanying image to this one, Plateosaurus Feeding, I described the world of the Triassic period, but how does the Plateosaurus fit into this world?. Where did they come from? Following the great Permian extinction event, the most catastrophic event in Earth's history, the reptiles which had survived were able to expand into new vacant niches in the dawning Triassic Period. Some of them expanded upon experiments of the recent past, and proceeded down the road to become mammals, with active metabolisms, live birth, and active parental care. Others also developed active metabolism and some degree of parental care, but continued to lay eggs. They lifted their bodies high off the ground on long hind legs, with specially-adapted hip joints, and became dinosaurs, the most successful group of animals ever to walk the earth, some of which are still with us today, as birds. Among the early dinosaurs were both carnivores and herbivores, all with a certain arrangement of hip bones. All known carnivorous dinosaurs, and all birds, evolved from this group. The herbivores grew in size, and developed long necks to increase their reach. One such group rose to early prominence in the Triassic, and these, the prosauropods, are best represented by Plateosaurus, one of the earliest yet largest prosauropods. A few million years later, however, the prosauropods were replaced by their relatives, the sauropods, who went on to become the largest creatures ever to live on land. Another type of herbivorous dinosaur altogether, with a slightly-different hip structure, was waiting in the wings, and would rise to prominence millions of years later on, in the form of armoured stegosaurs, and ankylosaurs, horned ceratopsians, and duck-billed hadrosaurs... But, in the late Triassic, with its head perched atop a long neck on an already-huge body, the Plateosaurus and its relatives could go after plant food beyond the reach of any previous animal. Few Triassic predators could bother an adult prosauropod; however, in the never-ending arms race that drives evolution, that situation would soon change...
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