pseudoceratites

from The Century Dictionary.

• An artificial group of ammonoid cephalopod genera with ceratitoid sutures found in Cretaceous rocks, comprising the retrogressive descendants of earlier, more complex Jurassic and Cretaceous types. Among the American genera included in this group may be mentioned Placenticeras, Sphenodiscus, Engonoceras, and Metengonoceras.