Ichthyosaurus fossil with foetus. Ichthyosaurs are now extinct marine reptiles belonging to the order Ichthyopterygia. They were widespread during much of the Mesozoic era and varied from a half up to fifteen metres in length. Ichthyosaurs exhibit a fair likeness with modern dolphins. This specimen is from the early Jurassic Posidonia Shales at Holzmaden, southern Germany. This specimen perished while pregnant, as evidenced by the remains of a foetus under the ribs at the righthand side. Actual length of this specimen is 3.5 meters.