Diplodocus, another sauropod, was 90 feet (27 meters) long. The plant-eating sauropod Brachiosaurus stood up to 52 feet (16 meters) tall, stretched some 85 feet (26 meters) long, and weighed more than 80 tons. On land, dinosaurs were making their mark in a big way-literally. Microscopic, free-floating plankton proliferated and may have turned parts of the ocean red. Coral reefs grew in the warm waters, and sponges, snails, and mollusks flourished. Fishlike ichthyosaurs, squidlike cephalopods, and coil-shelled ammonites were abundant. At the top of the food chain were the long-necked and paddle-finned plesiosaurs, giant marine crocodiles, sharks, and rays. The oceans, especially the newly formed shallow interior seas, teemed with diverse and abundant life. Ginkgoes carpeted the mid- to high northern latitudes, and podocarps, a type of conifer, were particularly successful south of the Equator. Palm tree-like cycads were abundant, as were conifers such as araucaria and pines. Dry deserts slowly took on a greener hue. Mountains rose on the seafloor, pushing sea levels higher and onto the continents.Īll this water gave the previously hot and dry climate a humid and drippy subtropical feel. New oceans flooded the spaces in between. The eastern portion-Antarctica, Madagascar, India, and Australia-split from the western half, Africa and South America. Gondwana, the southern half, began to break up by the mid-Jurassic. ![]() Laurasia, the northern half, broke up into North America and Eurasia. ![]() A Shifting Climate and Developing OceansĪt the start of the period, the breakup of the supercontinent Pangaea continued and accelerated. This was the Jurassic, which took place 199 to 145 million years ago. ![]() Sea monsters, sharks, and blood-red plankton.
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