Mixosaurus cornalianus (Baur 1887, Middle Triassic, 1-2m in length) is a derived ichthyosaur that retained a primitive tail. The flippers were similar in size. The cranium was depressed into twin basins on either side of a frontal/parietal crest. The neural spines were tall and narrow.
Derived from a sister to Phalarodon, Mixosaurus was a sister to Cymbospondylus.