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Middle and Late Jurassic Periods


Late Jurassic Dinosaurs

Pterosaurs glided and flapped their way to feeding grounds. There were two types of pterosaurs, ones with tails and ones without. The pterosaurs with tails did not last past the Late Jurassic; the pterosaurs without tails survived into the Cretaceous. Crocodiles, which replaced the phytosaurs of the Triassic, lurked in the undergrowth near water. Mammals, the descendants of the therapsids, were still running around. They were mostly shrewlike creatures that were four to five inches long, eating insects or chewing fruits and seeds. New insects were also evolving, including the ancestors of earwigs, flies, and bees, among others.

Jurassic Map
Collection of Publications International, Ltd.
Jurassic Map

The mammallike reptiles that were so important in the Triassic were gone by the Middle Jurassic, as were the rauisuchids and other archosaurs. Late in the Jurassic, small lizards, frogs, and salamanders crawled around under the cover of plants. Turtles, though not large, had also appeared. In the seas, corals, clams, and snails flourished, as did sharks and the marine reptiles, including plesiosaurs and ichthyosaurs.

This landscape provided food, forage, and home for the dinosaurs. As the land became greener in the Late Jurassic, the sauropods gained the advantage. They reached from China to North America to Africa. From the earliest sauropods in the Early and Middle Jurassic, and the carnivores that evolved with them, arose the giants of the Late Jurassic. Apatosaurus, Diplodocus, Brachiosaurus, Ultrasaurus, Supersaurus, Allosaurus, and Ceratosaurus roamed the earth. Others, like the ornithopods Stegosaurus and Camptosaurus, survived the great deserts of the Middle Jurassic and added to the growing group of dinosaurs. Late Jurassic dinosaurs were spectacular. They exceeded the imagination in size and form.