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.
Tetragonoceras is an extinct prehistoric nautiloid genus from the nautilid family Tetragonoceratidae that lived during the Middle Devonian, found in Canada.
Strophiceras is an extinct genus of cephalopods from the Order Nautilida, which includes, in a separate family, Nautilus and Allonautilus.
Homaloceras is an extinct nautiloid cephalopod from the Middle Devonian with a strongly curved shell, included in the nautilid family Centroceratidae.
Ankyloceras is a genus of Early Devonian cephalopods included in the oncocerid family Karoceratidae. The type species, Ankyloceras nesnayamiense named by Zhuravleva, 1974, comes from Nova Zemlya in Russia. Other species have been found in Japan, Morocco, and Russia.
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 Pacifiic. Valhalites belongs to the Koninckioceratidae, a family in the Tainoceratacea, a nautilid superfamily.
Streptoceras is a genus in the extinct oncocerid family Acleistoceratidae that plied the shallow sea floor from the Middle Silurian to the Middle Devonian. Streptoceras is characterized by a shell that is large but short in proportion (breviconic) with the ventral profile convex and dorsal profile concave in the posterior part, convex over the body chamber, then concave toward the front, like Amphycertoceras, but with a triangular shaped aperture. Streptoceras is found in the Middle Silurian of North America, in Ontario.
Shuranoceras is a genus in the extinct oncocerid family Karoceratidae that plied the shallow sea floor from the Early Silurian to the Early Devonian. Shuranoceras is characterized by a smooth, compressed, slowly enlarging orthoconic shellwith a ventral submarginal siphuncle composed of complex segments. Shuranoceras was found in middle Silurian strata in Ferghana, central Asia.
Mericoceras is an extinct nautiloid cephalopod that lived during the Late Devonian and possible as early as the Silurian.
Parasphaerorthoceras is an extinct orthocerid genus, a nautiloid cephalopod, that lived in what would be Europe and north Africa during the Silurian from 422.9—418.1 mya, having existed for approximately 4.8 million years.
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.
Trochoceras is a genus of trochoidally coiled nautiloid cephalopods placed in the nautilid family Rutoceratidae that lived during the Middle and Late Devonian in what is now central Europe.
Bojoscutellum is a genus of trilobites in the order Corynexochida family Styginidae.
Inversoceras is a genus of cephalopods in the order Oncocerida and the family Trimeroceratidae. These mollusks were fast-moving nektobenthic carnivores. They lived in the Silurian period, from the Lower Wenlock age to the Ludlow age.
Peismoceras is a genus of fossil Cephalopoda in the family Lechritrochoceratidae.
Adeloceras is a genus of Mississippian to Lower Permian nautiloid cephalopods included in the nautilid superfamily Aipocerataceae along with genera like Aipoceras, Asymptoceras, and Solenochilus.
Aktjubocheilus is a genus of oncocerid nautiloids from the Upper Devonian included in the Acleistoceratidae, a family characterized by depressed, or rarely compressed, exogastric brevicones and cyrtocones.
Balashovia is a genus of oncocerid nautiloids from the Middle Devonian,, included in the Archiacoceratidae, a family characterized by compressed, exogastric, cyrtocones with a large, actinosiphonate, dorsal siphuncle.
Germanonautilus is a cephalopod genus included in the nautilid family Tainoceratidae, found widespread in the Triassic of North America, Europe, Asia, and north Africa. The shell is a moderately involute nautilicone ; whorl section subquadrate to trapezoidal, widest across the umbilical shoulders, flanks flattened and ventrally convergent, venter flat and wide, dorsum narrowly and deeply impressed. The suture is with broad and deep lateral lobes and a shallow ventral lobe. The siphuncle is central and nummuloidal, composed of expanded segments that give a beaded appearance. Its color is usually brown-grey.
