Plesiosourus or Plesiosaurus: How To spell?
The word Plesiosourus is misspelled against Plesiosaurus, a noun meaning "A genus of large extinct marine reptiles, having a very long neck, a small head, and paddles for swimming. It lived in the Mesozoic age."
Word contains consecutive vowels 'AU' in between alphabets plesios & rus is misspelled as 'OU'Wrong Spelling:  plesios-ou-rus  Correct Spelling:  plesios-au-rus 
Check more misspelled words of Plesiosaurus to spell it correct.