The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species. All told, between 22 and 34 families and 165 to 184 genera have been recognised, making this the largest order of the subclass Nautiloidea.
The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian, in which the connecting rings are thin and siphuncle segments are variably expanded. At present the order consists of some 16 families, a few of which, such as the Oncoceratidae, Brevicoceratidae, and Acleistoceratidae contain a fair number of genera each while others like the Trimeroceratidae and Archiacoceratidae are represented by only two or three.
The Rutocertina is one of only three suborders in Shimankiy's (1957) classification of the Nautilida, the other two being the Lirocerina and Nautilina. Genera in the Rutocerina are redistributed in the Rutoceratina, Tainoceratina, and Centroceratina. The Lirocerina is redefined as the Liroceratina, and Nautilina.remains as is. In general terms these are similar to the simpler classification proposed by Kümmel 1964, wherein the Nautilida is divided into five superfamilies, the Tainocerataceae, Trigonocerataceae, Clydonautilacea, Aipocerataceae, and Nautilaceae. Shimanskiy's classification involves 34 families, Kümmel's only twenty-seven.
Lamellorthoceratidae is a family of fossil orthoceratoids in the Orthocerida, defined by Curt Teichert in 1961. The lamellorthoceratids are placed in the superfamily Orthocerataceae in the Treatise on Invertebrate Paleontology.
Endolobus is an extinct genus from the nautiloid order, Nautilida. Nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species, including Nautilus. Endolubus is included in the family Koninckioceratidae which is part of the superfamily Tainoceratoidea.
Tetrapleuroceras is an extinct prehistoric nautiloid from the Lower Permian of the Urals in Russia. Nautilids are a type of nautiloid, a subclass of shelled cephalopods that were once diverse and numerous but now only represented by Nautilus and Allonautilus
Valhallites is an extinct genus in the nautiloid order Nautilida which includes the living Nautilus found in the tropical western Pacific Ocean. Valhalites belongs to the Koninckioceratidae, a family in the Tainoceratoidea, a nautilid superfamily.
The Tainoceratoidea are a superfamily in the cephalopod order Nautilida characterized by straight to loosely coiled shells, generally to a degree such that the width is greater than the height, to quadrate whorl section. Many bore spines, ribs, frills, wings, or nodes. In early forms, the siphuncle is generally near ventral, but more variable in advanced forms.
Baltoceratidae is an extinct family of orthoconic cephalopods belonging to the subclass Nautiloidea endemic to what would be Asia, Australia, Europe, North America, and South America during the Ordovician living from about 480–460 mya, existing for approximately 20 million years.
Solenochilus, type genus of the Solenochilidae is an extinct cosmopotilian nautilid from the Lower Pennsylvanian to the Lower Permian with a rapidly expanding, coiled globular shell with few whorls, from which prominent spines extend laterally from the umbilical area at maturity. Solenochilus is derived from the Upper Mississippian Acanthonautilus, principally through evolutionary changes in the siphuncle.
The Clydonautiloidea are a superfamily within the nautiloid order Nautilida characterized by smooth, generally globular, shells with nearly straight sutures, in early forms, but developing highly differentiated sutures in some later forms. Where known, the siphuncle tends to be central to subcentral.
The Trigonoceratoidea are a superfamily within the Nautilida that ranged from the Devonian to the Triassic, thought to have contained the source for the Nautilaceae in which Nautilus is found.
Rutoceratidae is a family of prototypical nautilids, derived probably from either Brevicoceratidae or Acleistoceratidae of the order Oncocerida early in the Devonian. Rutoceratidae comprise a family within the oncocerid superfamily Tainocerataceae They are generally characterized by cyrtoconic and gyroconic shells, commonly with spines, nodes, or frills, although some included genera are almost orthoconic, and a commonly empty, tubular ventral siphuncle.
Grypoceratidae is the longest-lived family of the Trigonoceratoidea, or of the near equivalent Centroceratina; members of the Nautilida from the Upper Paleozoic and Triassic.
The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous (Mississippian) to the Early Permian.
The Centroceratidae is the ancestral family of the Trigonoceratoidea and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida
Pleuronautilus is a nautiloid genus; family Tainoceratidae, order Nautilida.
The Rhiphaeoceratidae are a small family of nautilids included in the superfamily Tainoceratoidea that comprises four very similar genera. These genera are characterized by a perforate umbilicus and little more than a single evolute coil. Whorl sections are oval, subquadrate, or subtrapezoidal. Sutures bend forward on the outer rim, forming wide shallow ventral saddles and dip strongly to the rear on the inner rim, forming deep dorsal lobes.
The Aipoceratidae are a small family of Carboniferous nautilids which have smooth shells and loosely coiled to faintly impressed whorls and in which the aperture may be modified at maturity. The Aipoceratidae include the Lower Carboniferous Aipoceras and Asymptoceras, and Librovitschiceras from the Upper Carboniferous. The Solenochilidae are closely related.
Solenochilidae is a small family of Carboniferous and Early Permian nautilids, similar and related to the Aipoceratidae that comprises genera with whorls in contact and which develop laterally projecting umbilical spines by maturity. The included genera Solenochilus and Acanthonautilus are quite similar in external form but differ in their siphuncles. Those of Solenochilus have more strongly inflated siphuncle segments and more tightly curved septal necks.
