Placoganoidea or Placoganoidei: How To spell?

The word Placoganoidea is misspelled against Placoganoidei, a noun meaning "A division of ganoid fishes including those that have large external bony plates and a cartilaginous skeleton."

Word ends with consecutive vowels 'EI' preceded by alphabets 'placoganoid' is misspelled as 'EA'
Wrong Spelling:  placoganoid-ea 
Correct Spelling:  placoganoid-ei 
Find more incorrect spellings of Placoganoidei to spell right way.