Plesiosauroidea

Plesiosauroidea ( /ˈpliːsiəsɔər/; Greek: plēsios/πλησιος 'near' or 'close to' and sauros/σαυρος 'lizard') is an extinct clade of carnivorous plesiosaur marine reptiles. Plesiosauroids, are known from the Jurassic and Cretaceous Periods. After their discovery, some plesiosauroids were somewhat fancifully said to have resembled "a snake threaded through the shell of a turtle", although they had no shell.