Marine reptile fossils can be found in strata dating back 299 million years, beginning in the Permian period of the Paleozoic era. The earliest known marine reptile is Mesosaurus tenuidens, and many different types of reptiles have evolved to live in oceanic environments in the hundreds of millions of years since. These include animals such as placodonts, nothosaurs, plesiosaurs, turtles, and lizards.
