 The femur is long, but the very end is not fully preserved.Due to the robusticity of the femur Osborn & Mook in 1921 referred "Amphicoelias latus" to "Camarasaurus supremus", making "C. supremus" the valid name for the material once called "A. latus".The third named "Amphicoelias" species, "A. fragillimus", was known only from a single, incomplete tall neural arch, either last or second to last in the series of back vertebrae.