Plesiosaaria or Plesiosauria: How To spell?
The word Plesiosaaria is misspelled against Plesiosauria, a noun meaning "An extinct order of Mesozoic marine reptiles including the genera Plesiosaurus, and allied forms; -- called also Sauropterygia."
Word contains consecutive vowels 'AU' in between alphabets plesios & ria is misspelled as 'AA'Wrong Spelling:  plesios-aa-ria  Correct Spelling:  plesios-au-ria 
Find more incorrect spellings of Plesiosauria to spell right way.