| Tetrapleuroceras Temporal range: L Permian | |
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| Genus: | Tetrapleuroceras Shimansky (1957) |
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
Tetrapleuroceras is one of two genera that Shimianky combined as the Neptunoceratidae in 1957, the other being Neptunoceras . The Neptunoceratidae, according to Rousseau Flower (1963) is doubtfully distinct from the Scyphoceratidae, a family from the Lower Permian included in the Aipocerataceae.(Kummel 1964.
The Scyphoceratidae, to which Tetrapleuroceras is assigned (Flower 1963) are cyrtoconic or possibly loosely coiled nautilids with smooth or ribbed shell, generally short phragmocones, and slightly expanded siphuncle segments.
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.
Sholakoceras is an extinct genus of nautiloid cephalopods from the Lower Permian of southern Russia, included in the Tainoceratacean family Rhiphaeoceratidae,(order Nautilida). The shell of Shalakoceras is evolute with a perforate umbilicus. Whorl sections are subquadrate with the ventral and lateral sides flattened and ventral and umbilical shoulders rounded. Lateral areas bear short, slightly oblique ribs. sutures form broad ventral saddles with a slight, shallow lobe, very shallow lateral lobes, and a deep funnel-shaped dorsal lobe.
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.
Permoceras, the sole member of the family Permoceratidae, is a genus of coiled nautiloids with a smooth, compressed involute shell, whorls higher than wide, earlier whorls hidden from view. The venter is rounded as are the ventral and umbilical shoulders, the flanks flattened. The siphuncle is ventrally subcentral. The suture, which is most characteristic, has a deep, narrow pointed ventral lobe and large, asymmetrical pointed lobes on either side.
Jovellania is a genus of extinct prehistoric nautiloids from the order Oncocerida known from the Lower Devonian of Europe. Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.
Kionoceras is an extinct nautiloid cephalopod genus included in the orthocerid family Kionoceratidae with scattered worldwide distribution from the Middle Ordovician to the Lower Permian. Kionoceratids are orthocerids with prominent longitudinal ornamentation on their shells, sometimes augmented by secondary transverse ornamenttion. Orthocerids are, of course, prehistoric nautiloides with generally straight and elongate shells, mostly with central or subcentral siphuncles.
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 Taintocerataceae.
Brevicoceras is an extinct nautiloid genus from the order Oncocerida with wide distribution in the Middle Devonian in Eastern North America, Russia and Morocco. Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.
Permonautilus is an extinct genus of nautilids from the Upper Permian of Russia, named and described by Kruglov in 1933. Permonautilus is an involute, globular, spinose member of the Lirocertidae which are included in the Clydonautilaceae. Whorl sections are broad, with a rounded venter. The umbilicus in the middle of the shell is deep, from which spine-like processes extend laterally in the mature portion near the aperture. The siphuncle in Permonautilus is subcentral, the suture, slightly sinuous.
Titanoceras is an extinct genus in the nautiloid order Nautilida from the Pennsylvanian and Lower Permian of North America and Western Australia.
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.
Tylonautilus is an extinct genus in the nautiloid order Nautilida from the Lower Carboniferous of Europe and Permian of Japan.
Heminautilus is an extinct genus of nautiloids from the nautilacean family Cenoceratidae that lived during the Early Cretaceous. Fossils of Heminautilus have been registered in rocks of Barremian and Aptian age. Nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.
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.
Stearoceras is an extinct genus of prehistoric nautiloids from the Lower Pennsylvanian - Lower Permian with a fair worldwide distribution.(Kümmel 1964)
Triboloceras is the name given to an extinct nautiloid genus from the Lower Carboniferous (Mississippian), included in the nautilid family Trigonoceratidae characterized by an evolute shell bearing longitudinal ribs, with whorls in contact except in the early and very latest growth stages. Chambers are short, sutures tend for form ventral and in some cases dorsal and lateral lobes. The siphuncle is small, tubular, and subcentral.
The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous (Mississippian) to the Early Permian.
Pleuronautilus is a Nautiloid genus; family Tainoceratidae, order Nautilida.
