Ceratosaurus nasicornis was named by Marsh (1884). Its type specimen is USNM 4735, a skeleton, and it is not a trace fossil. Its type locality is Felch Quarry 1, Garden Park (YPM), which is in a Kimmeridgian/Tithonian channel sandstone/claystone in the Morrison Formation of Colorado.
It was recombined as Megalosaurus nasicornis by Cope (1892).