 In a 2010 review of Stegosaurus species , Peter Galton suggested that the arrangement of the plates on the back may have varied between species , and that the pattern of plates as viewed in profile may have been important for species recognition . Galton noted that the plated in S. stenops have been found articulated in two staggered rows , rather than paired . Fewer S. ungulatus plates have been found , and none articulated , making the arrangement in this species more difficult to determine . However , the type specimen of S. ungulatus preserves two flattened spine @-@ like plates from the tail that are nearly identical in shape and size , but are mirror images of each other , suggesting that at least these were arranged in pairs . 
