Looks like they have a triceratops as ichthyosaur ancestor, and maybe a turtle as plesiosaur ancestor. A very obviously fully aquatic animal is in the "ambiguously aquatic" ichthyosaur line. A front leg of a mosasaur ancestor gets expanded into a hind leg.
Is this an AI generated diagram? If so, shame on them for either not noticing the wrongness, or being sloppy and leaving it in.
