sentences:  Tornoceratids are subdiscoidal goniatitids with biconvex growth lines and sutures that form 6 to 10 lobes, the ventral one undivided, the lateral ones originating as subdivisions of external and internal lateral saddle.They are derived from the Anarcestida.Tornoceratidae as now understood is essentially the Tornoceratidae of Arthaber (1911) described in the American Treatise on Invertebrate Paleontology, Part L, revised to include three subfamilies, the Tornoceratinae, Aulatornoceratinae, and Falcitornoceratinae.