an order of extinct reptiles of the superorder Thecodontia, subclass Archosauria. The phytosaurs, which lived during the late Triassic, measured as much as 5–6 m in length and closely resembled crocodiles, both externally and in the details of their body structure. Most scientists consider this similarity to be an example of convergence; however, some think the phytosaurs were ancestors of the crocodile.
The phytosaurs had elongated snouts with the narial openings placed far back; the eye sockets were turned upward. The hind extremities were only slightly longer than the front extremities. The body was covered with a well-developed leathery armor. Members of the order lived in freshwater basins and fed mainly on fish. Their remains have been found in Upper Triassic deposits in Western Europe, North America, and Asia.