 A number of species assigned to Allosaurus are no longer recognized as valid , for one reason or another . Species " A. <unk> " , seen in <unk> , 1887 , and <unk> , 1912 , is a typographical error for A. fragilis . Marsh 's A. ferox ( 1896 ; not to be confused with his 1884 Labrosaurus ferox , also part of Allosaurus taxonomy ) was coined for a partial skull in a footnote , and has been recognized as a specimen of A fragilis . A. lucaris , another Marsh name , was given to a partial skeleton in 1878 . He later decided it warranted its own genus , Labrosaurus , but this has not been accepted , and A. lucaris is also regarded as another specimen of A. fragilis . Allosaurus lucaris , is known mostly from vertebrae , sharing characters with Allosaurus . Paul and Carpenter stated that the type specimen of this species , YPM 1931 , was from a younger age than Allosaurus , and might represent a different genus . However , they found that the specimen was <unk> , and thus A. lucaris was a nomen dubium . " A. <unk> " , an informally described species coined by Pickering in 1996 , is a <unk> of the A. atrox versus A. fragilis debate using a better specimen to represent the A. atrox form , and has not been recognized . 
