Pleuronautiloidea Hyatt 1900

Superfamily Pleuronautiloidea Hyatt, 1900 Diagnosis Superfamily of the suborder Tainoceratina with a discoidal, subinvolute to subevolute conch. Whorl profile in phylogenetically early species subquadrate with distinct ventrolateral shoulder and distinct umbilical margin. Derived species show a variation of modifications including trapezoidal, inverted trapezoidal or hexagonal whorl profiles with a less angular ventrolateral shoulder and umbilical margin. Whorl overlap is always very small. Sculpture in phylogenetically early species with transverse ribs and ventrolateral nodes, in derived species often with ribs and several rows of nodes. Septa simply domed, in derived species with a dorsal inflexion that produces an annular process. Suture line with broadly rounded lateral lobe and shallow lobe or low saddle on the venter (from Korn 2025). Included families Pleuronautilidae Hyatt, 1900 (Permian to Triassic); Gzheloceratidae Ruzhencev & Shimansky, 1954 (Carboniferous to Permian); Mosquoceratidae Ruzhencev & Shimansky, 1954 (Carboniferous to Permian); Aktubonautilidae Ruzhencev & Shimansky, 1954 (Permian); Rhiphaeoceratidae Ruzhencev & Shimansky, 1954 (Permian); Metacoceratidae Korn, 2025 (Carboniferous to Permian); Foordiceratidae Korn, 2025 (Permian). Remarks A detailed discussion of the superfamily Pleuronautiloidea has been given by Korn (2025).