Euryapsids were a group of marine reptiles (now extinct) that had a single skull opening behind the eye socket, a subgroup of the diapsids. Euryapsids include plesiosaurs , nothosaurs , placodonts , and ichthyosaurs . Found on http://www.enchantedlearning.com/subjects/dinosaurs/glossary/
Euryapsids were a group of marine reptiles (now extinct) that had a single skull opening behind the eye socket, a subgroup of the diapsids. Euryapsids include plesiosaurs , nothosaurs , placodonts , and ichthyosaurs .