Placodontia

an order of fossil marine reptiles of the subclass Synaptosauria. Placodonts lived during the Triassic. They resembled turtles owing to their armored back and abdomen. Their elongate body, which reached 2.5 m long, resembled that of a dugong. The skull was massive and enlarged posteriorly. The teeth were powerful and adapted for grinding the shells of mol-lusks—the principal food of placodonts. The limbs were flipperlike and had shortened phalanges. Placodonts have been found in Western Europe.