 Early-diverging ichthyosauriforms with lizard-shaped bodies and elongate, flukeless tails, like "Cartorhynchus", would have employed anguilliform (eel-like) swimming, while later ichthyosauriforms with deeper, fish-like bodies and well-defined tail flukes would have employed carangiform (mackarel-like) swimming.It is generally thought that anguilliform swimming is less efficient than carangiform swimming.Indeed, Gutarra and colleagues found that the energetic cost of swimming at was 24 to 42 times higher in "Cartorhynchus" than the ichthyosaur "Ophthalmosaurus" (depending on whether swimming mode is accounted for), and its drag coefficient was 15% higher than that of the bottlenose dolphin.