 Marsh named a second species , Stegosaurus ungulatus , in 1879 , and finally gave a more detailed description of all the Stegosaurus fossils collected to far the following year . In 1881 , he named a third species Stegosaurus " affinis " , based only on a hip bone . This species is generally agreed to have been inadequately described , and therefore is a nomen nudum ( a name lacking a formal description ) . The specimen was later lost . Marsh continued to collect and examine new Stegosaurus specimens , and in 1887 he named three new species : Stegosaurus stenops , S. duplex , and S. sulcatus . Though it had not yet been completely prepared , the nearly complete and articulated type specimen of Stegosaurus stenops allowed Marsh to complete the first attempt at a reconstructed Stegosaurus skeleton . This first reconstruction , of S. ungulatus with missing parts filled in from S. stenops , was published by Marsh in 1891 . ( In 1893 , Richard Lydekker mistakenly re @-@ published Marsh 's drawing under the label Hypsirhophus ) . 
