Ichthyosaur

Stenopterygius quadriscissus is an ichthyosaur from the Lower Jurassic shales of Holzmaden (Germany) where, about 180 million years ago, there was a wide, subtropical marine bay with poorly oxygenated bottom waters that have fostered an exceptional fossilization of organisms. Widespread in the seas of the Mesozoic, ichthyosaurs represent the largest and most advanced group of reptiles that specialized for the marine environment, and probably the only ones among them to carry out the entire life cycle in the sea, like present day cetaceans (Giancarlo Ligabue Foundation Collection).