Mixosaurus was an ichthyosaur which lived in different locations around the world. It lived during the middle Triassic.
In appearance Mixosaurus seems intermediary between the eel-like forms typified by Cymbospondylus, and the more familiar dolphin-shaped forms such as the late Ichthyosaurus, hence the name. The long tail with its low fin suggests that it was a slow swimmer, moving forward by undulation of the tail.
The body and tail are long, with the tail having a low fin that is not as well-developed as the shark-like fin of the late types, and there is a stabilizing dorsal fin on the back. The paddle-like fins are still made up of five toes each, unlike the muliti-toed structure found in later ichthyosaurs. However, each toe has more individual bones than is usual (polyphalangy) and the front limbs are longer than the rear.