A Mesozoic marine reptile of a group characterized by a single upper temporal opening in the skull, including the nothosaurs, plesiosaurs, and ichthyosaurs.
Sometimes placed in a subclass Euryapsida, though this taxon is no longer widely recognized‘Turtles were seen as close relatives of sauropterygians (or even members of Sauropterygia) in the analyses including euryapsids; without euryapsids, those matrices support nondiapsid affinities for turtles.’
- ‘These forms share the possession of a single upper temporal fenestra (the ‘euryapsid’ condition), and they were frequently classified together as members of Euryapsida.’
- ‘Turtles are outside Diapsida when euryapsids are not included, but diapsids when they are.’
From Greek eurus ‘wide’ + apsis, apsid- ‘arch’.