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Which ammonoids survived the end-Triassic extinction?
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Triassic Period
Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the early Triassic Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.
At the end of the Triassic Period, the vast majority of ammonoid genera, including many ceratitids, went extinct. The only group of ammonoids that survived this mass extinction event were the phylloceratids.123
These surviving phylloceratids, which were characterized by smooth shells and more complex suture lines, served as the ancestors for the diverse array of ammonites that underwent explosive radiation during the subsequent Jurassic Period.324