This
list of nautiloids is a comprehensive listing of all
generaIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
that have ever been included in the subclass
NautiloidNautiloids are a large and diverse group of marine cephalopods belonging to the subclass Nautiloidea that began in the Late Cambrian and are represented today by the living Nautilus. Nautiloids flourished during the early Paleozoic era, where they constituted the main predatory animals, and...
ea, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (
nomina dubiaIn zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
), or were not formally published (
nomina nudaThe phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
), as well as junior synonyms of more established names, and genera that are no longer considered nautiloids.
Most of the listed genera are found in Part K of the
Treatise on Invertebrate PaleontologyThe Treatise on Invertebrate Paleontology published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and...
. Some, added since the year of publication (1964) are found simply in various scientific journals and special publications. The named genera are based on type specimens which are housed in various museums and other academic institutions worldwide, available to interested researchers.
A
- †Acanthonautilus
Acanthonautilus is an extinct genus in the nautilid family Solenochildae from the Upper Mississippian of North America and equivalent strata in Europe, first described by Foord in 1896....
- †Acaroceras
- †Acleistoceras
Acleistoceras is a genus of the oncocerid, nautiloid family Acleistoceratidae that lived in the shallow seas that covered much of North America during the Devonian; living from 409—383.7 mya, existing for approximately .-Taxonomy:...
- †Acrosphaerorthoceras
- †Actinoceras
Actinoceras is the principal and root genus of the Actinoceratidae, a major family in the Actinocerida, that lived during the Middle and Late Ordovician.- Morphology:...
- †Actinomorpha
- †Adamsoceras
Adamsoceras is an actinocerid of the family Wutinoceratidae, with spheroidal siphuncle segments like Ormoceras but having a reticular canal system like Wutinoceras. Adamsoceras has a slender, gently expanding, orthoconic shell that is slightly broader than high, i.e...
- †Adeloceras
- †Adelphoceras
- †Adnatoceras
- †Aethiosolen
Aethiosolen is an orthocerid genus in the family Orthoceratidae with an annulated orthoconic shell.Annuli, transverse elevations on the shell, are broad and of low amplitude with spacings in the range of 4 to 6 mm and height of less than 1 mm. Camerae are short, septal spacing on the...
- †Aethoceras
- †Agrioceras
- †Aigoceras
- †Aipetoceras
- †Aipoceras
- †Akroceras
- †Aktjubocheilus
- †Alaskoceras
- †Albertoceras
- †Alethynoceras
- †Aletoceras
- †Alexandronautilus
- †Allanoceras
- †Alloceras
- Allonautilus
The genus Allonautilus contains two species of nautiluses, which differ significantly in terms of morphology from those placed in the sister taxon Nautilus. Allonautilus is now thought to be a descendant of Nautilus and the latter paraphyletic.-External links:*...
- †Allotrioceras
Allotrioceras is a tubular fossil from the middle Chazyan of New York state, collected by Rousseau H. Flower and included by him in the Endocerida and placed in a new family, the Allotrioceratidae...
- †Allumettoceras
The Tripteroceratidae is a family of depressed, straight to slightly curved longiconic cephalopods from the middle and upper Ordovician with generally flattened venters and suborthochoantic to cyrtochoantitic, empty, siphuncles, tentatively included in the Oncocerida...
- †Almaloceras
- †Alpenoceras
- †Aluveroceras
- †Amphicyrtoceras
- †Amsleroceras
- †Anamesoceras
- †Anaspyroceras
- †Anastomoceras
- †Ancistroceras
Ancistroceras is one of the two ancestral lituitids from the late Early Ordovician . The other being Holmiceras.The shell is weakly annulate, starts off with 1.5 to 2 contiguous or slightly separated whorls followed by a rapidly expanding orthocone with an apical angle of about 30 deg...
- †Andreioceras
- †Anepheloceras
- †Angelinoceras
Angelinoceras is a lituitid from the Middle Ordovician that starts off with a open spiral of about 1.5 strongly compressed whorls followed by an orthoconic section that continues to expand for a length about equal to the diameter of the coiled portion before retaining a more or less consistent...
- †Anglicornus
- †Anglonautlis
- †Anguloceras
- †Anhuiceras
- †Ankyloceras
Ankyloceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Annoceras
- †Anomaloceras
- †Anomeioceras
- †Anonymoceras
- †Anoploceras
Anoploceras is a Middle and Upper Triassic nautiloid included in the Tainoceratidae, known from eastern Europe. The shell is evolute with only a slight overlap of previous whorls. Whorl section is subquadrate, like Pleuronautilus, only depressed. Flanks have conspicuous ribs that may be somewhat...
- †Antacaroceras
- †Anthoceras
Anthoceras is a straight, annulated, proterocamerioceratid from the Lower Ordovician, found in North America, NW Australia, and Siberia. The cross section is circular, the siphuncle moderately large, and marginal...
- †Anthomorpha
- †Antigyroceras
Antigyroceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Antiphragmoceras
- †Antiplectoceras
- †Antonoceras
- †Aphelaeceras
Aphelaeceras is an extinct genus from the nautilid family Trigonoceratidae which is part of the Trigonocerataceae, that lived during the Mississippian Period in the late Paleozoic—a nautiloid cephalopod...
- †Aphetoceras
Aphetoceras is a genus of Tarphycerida cephalopod within the Estonioceratidae; loosely coiled without an impression along the dorsal margin; early whorls barely teaching, separating then diverging in the final mature whorl; weakly ribbed in some. The cross section of Aphetoceras is higher than...
- †Aphractus
- †Aphragmites
- †Aphyctoceras
- †Apioceras
- †Aploceras
- †Apocrinoceras
- †Apogonoceras
- †Apsidoceras
- †Archiacoceras
- †Argocheilus
- †Arionoceras
Arionocerasis an extinct orthocerid genus from the Middle and Upper Silurian, of Europe that is estimated to have lived from 422.9—418.1 mya, existing for approximately .-Taxonomy:...
- †Arkoceras
The Trocholitidae are Tarphycerida with whorls in close contact as with the Tarphyceratidae, but in which the siphuncle, similar in structure, becomes dorsal. The Trocholitidae are derived from the Tarphyceratidae, perhaps from different tarphyceratids....
- †Arkonoceras
- †Armenoceras
Armenoceras is the principal genus of the Armenoceratidae, ranging from the late Whiterockian Stage in the early Middle Ordovician, through the remainder of the period and on into the Upper Silurian....
- †Arpaoceras
- †Arterioceras
- †Arthrophyllum
The Lamellorthoceratidae is a family of fossil nautiloids in the Orthocerida, defined by Curt Teichert in 1961. The lamellorthoceratids are placed in the superfamily Orthocerataceae in the Treatise on Invertebrate Paleontology ....
- †Articheilus
- †Asaphiceras
- †Asbestoceras
- †Ascoceras
- †Askeatonolucidum
Askeatonolucidum is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Astoceras
- †Asymptoceras
- †Athanatoceras
- †Atomoceras
- †Atopoceras
- †Aturia
The Aturiidae constitutes a family of Paleocene to Miocene nautilids , established by Campman in 1857 for Aturia Bronn, 1838, and are included in the superfamily Nautilaceae in Kümmel 1964....
- †Aturoidea
- †Augustoceras
- †Aulaconautilus
- †Aulametacoceras
- †Austinoceras
- †Avilionella
- †Avoceras
B
- †Bactroceras
Bactroceras is a genus of the family Baltoceratidae, orthoceroid cephalapods that lived during the early Middle Ordovician, from about 472—464 mya, existing for approximately 8 million years.-Taxonomy:...
- †Badouceras
- †Baeopleuroceras
- †Bakeroceras
- †Balashovia
- †Balticoceras
Balticoceras is a genus in the Orthocerid family, Orthoceratidae, from the Upper Ordovician of Estonia, closely related to Michelinoceras. Balticoceras is distinguished by its straight shells with a subcircular cross section, broadly flattened ventrally and evenly rounded dorsally, and by its...
- †Baltoceras
Baltoceras is a member of the Ellesmerocerida, included in the family, Baltoceratidae. The shell of Baltoceras is slender with a subcircular cross section, straight transverse sutures, and a large siphuncle in contact with the venter...
- †Bambusoceras
- †Barnesoceras
- †Barrandeoceras
- †Bassleroceras
Bassleroceras is an elongate upwardly curved, exogastric, genus with the venter on the under side more sharply rouned than the dorsum on the upper...
- †Bastindoceras
- †Bateroboceras
- †Bathmoceras
Bathmoceras is a genus of the Ellesmerocerida, placed in the family Bathmoceratidae, in which Furnish and Glenister 1964 also include Eothinceras. Flower 1964 separates the two genera into their respective families which he included in his suborder, CyrtocerininaThe shells of Bathmoceras are rather...
- †Baykonaroceras
- †Beekmanoceras
Beekmanoceras is a small cephalopod from the Middle Canadian of New York with a gyroconic shell in which the siphuncle is on the inner or concave side of the whorl. Furnish and Glenister placed Beekmanoceras in the Trocholitidae ,interpreting the curvature to be exogastastric and the siphuncle to...
- †Belloceras
Belloceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Beloitoceras
- †Bentoceras
- †Bergoceras
- †Bickmorites
Bickmorites is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Bifoveoceras
- †Billingsites
- †Bistrialites
Bistrialites is an involute, globose Clydonautilacean belonging to the Liroceratidae with a reniform whorl section, large funnel shaped umbilcus, smooth surface except for spiral ornament in the region of the umbilical shoulder. Bistrialites comes from the Lower Carboniferous of...
- †Bitaunioceras
Bitaunioceras is a Permian michelinocerin orthocerid with a gradually expanding orthoconic shell with straight transverse sutures and a small, orthochoanitic, subcentral siphuncle....
- †Blakeoceras
Blakeoceras is a nautiloid cephalopod from the Oncocerida family Nothoceratidae with a curved shell that lived in shallow seas from the Silurian to the middle Devonian in what has become Europe....
- †Blastocerina
- †Bodieceras
- †Bodoceras
- †Bogoslovskya
Bogoslovskya is an extinct orthoceroid cephalopod genus that lived in what is now Asia from the Devonian to the Permian.-Taxonomy:Bogoslovskya was named by Zhuravleva...
- †Bohemites
- †Bolloceras
- †Brachycycloceras
- †Brachydomoceras
- †Bradfordoceras
- †Brevicoceras
Brevicoceras is an extinct prehistoric nautiloid genus from the order Oncocerida with wide distribution in the Middle Devonian in Eastern North America, Russia and Morocco...
- †Bridgeoceras
- †Brodekoceras
- †Broeggeroceras
- †Buchanoceras
- †Buehleroceras
- †Burenoceras
Burenoceras is a genus of small, even tiny, Gasconadian cyrtoconic ellesmeroceratids in which the phragmocone -the chambered portion- is shorter that the living chamber....
- †Buttsoceras
- †Byronoceras
C
- †Calchasiceras
- †Calhounoceras
- †Callaionautilus
- †Calocyrtoceras
- †Cameroceras
- †Campbelloceras
Campbelloceras: a tarphyceratid with a circular whorl section, only slightly impressed, and a siphuncle that is close to the venter in all growth stages. Differs from Tarphyceras in that the rate of expansion is greater, the siphuncle is proportionally largers, and an impression is shallower...
- †Campendoceras
Campendoceras is a proterocameroceratid genus from the Lower Ordovician of NW Australia and possibly Estonia that can be recognized by its slender, weakly endogastric, longiconic and annulate shell and large marginal siphuncle that contains endocones....
- †Campyloceras
- †Capriocornites
- †Carbactinoceras
- †Carinonautilus
- †Carlloceras
- †Carotites
- †Cartersoceras
Cartersoceras is a nautiloid cephalopod genus placed in the Orthocerid family Baltoceratidae, established by Rousseau Flower, 1964, for species formally included in part in Murrayoceras, and in part in "Sacotoceras", which are typical of Murrayoceras in all features except that the siphuncle...
- †Caseoceras
- †Cassinoceras
Cassinoceras is of the nautiloid genus belonging to the endocerid family Piloceratidae that comes from the late Early Ordovician of eastern North America and adjacent terratories....
- †Casteroceras
- †Catastroboceras
- †Catoraphinoceras
- †Catyrephoceras
Lechritrochoceratidae is a family of derived tarphycerids from the middle and upper Silurian, once included in the now largely abandoned Barrandeocerida, which comprise dextrally torticonic genera with costate shells and ventrally displaced siphuncles. Offset coiling in low spired. Rate of...
- †Cayogoceras
- †Cayutoceras
- †Cedarvilleoceras
- †Celox
- †Cenoceras
The genus Cenoceras is a member of the Nautilidae, which in turn makes up part of the superfamily Nautilaceae.Cenoceras is variable in form, depending on species; ranges from evolute to involute, compressed lenticular to globose with rounded to flattened venter and flanks. The suture generally has...
- †Centroceras
- †Centrocyrtoceras
- †Centrocyrtocerina
- †Centrolitoceras
- †Centroonoceras
Centroonoceras is a middle Ordovician cyrtoconic nautiloid cephalopod, otherwise similar to the orthoconic Sactorthoceras and also included in the Sactorthoceratidae...
- †Centrorizoceras
- †Centrotarphyceras
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from Bassleroceras or possibly from some member of the...
- †Chabactoceras
- †Chadwickoceras
- †Charactoceras
- †Charactocerina
- †Chazyoceras
Chazyoceras is a moderately large endocerid included in the Endoceratidae with a Nanno type apex and a ventral siphuncle with a holochoanitic wall, characteristic of the family. The siphuncle swelling at the apex is subtriangular in longitudinal profile. Endocones are of medium length.Chazyoceras...
- †Chepuloceras
- †Chicagooceras
- †Chidleyenoceras
- †Choanoceras
The Choanoceratidae is a small, mono-generic, family of extinct nautiloid cephalopods in the order Orthocerida that lived in what would be Europe during the middle Silurian from428.2—426.2 mya, existing for approximately .-Taxonomy:...
- †Chouteauoceras
Chouteauceras is an openly coiled, gyroconic, nautiloid cephalopod from the Mississippian of North America belonging to the Nautilid family Trigonoceratidae, and superfamily Trigonocerataceae....
- †Chrysoceras
- †Chuticeras
- †Cimomia
- †Cinctoceras
Mandaloceratidae is a family in the nautiloid cephalopod order, Discosorida, from the Middle and Upper Silurian characterized by essentially straight, breviconic shells, most with a faintly exogastric shape produced by the profile of the body chamber...
- †Clarkesvillia
Clarkesvillia is an upper Ordovician westonocerid genus the differs from Faberoceras in having a more flattened venter and from the later Glyptodendron in having its siphuncle more ventrally located.-references:...
- †Clarkoceras
Clarkoceras is a breviconic ellesmerocerid cephalopod, one of only two genera known to have crossed from the Late Cambrian, Trempealeauan, into the Early Ordovician, Gasconadian...
- †Clathroceras
- †Clelandoceras
- †Cliftonoceras
Cliftonoceras is a barrandeoceroid type tarphycerid from the Uranoceratidae characterized by a smooth gyroconic shell with a rounded dorsum and flattened venter, and by a subvental siphuncle composed of thin connecting rings and necks that are straight ventrally, recumbent dorsally.Cliftonoceras...
- †Clinoceras
- †Clionyssiceras
- †Clitendoceras
Clitendoceras is a member of the Endocerida from the Lower Ordovician with an elongate shell with a slight downward, endogastric, curvature and a siphuncle that lay along the ventral margin. Common for endocerids, the chambers are short and the septa close spaced with sutures sloping forward...
- †Clydonautilus
- †Clymenonautilus
The Syringonautilidae comprise the last of the Trigonocerataceae and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. The Syringonautilidae, itself, is a strictly Triassic family, derived early in the Triassic...
- †Clytoceras
- †Cochlioceras
Cochlioceras is an extinct baltoceratid genus from the lower and middle Ordovician of what are now Europe, the U.S , and China, having existed for approximately 14 million years, from about 478 to 464 mya. -Taxonomy:...
- †Codoceras
- †Coelocyrtoceras
- †Coelogasteroceras
- †Coloceras
- †Columenoceras
- †Comaroceras
- †Condraoceras
Condraoceras is a liroceratid from the Pennsylvanian of North America and Lower Permian of Europe with a compressed, involute, nautiliconic shell; subcircular whorl section; small umbilicus with a rounded shoulder; suture with shallow ventral and lateral lobes; and narrow subcentral...
- †Conocerina
- †Conostichoceras
Conostichoceras is an exogastric, breviconic oncocerid included in the family Nothoceratidae, known from the Middle Devonian of central Europe and Upper Devonian of Australia...
- †Conradoceras
- †Cooperoceras
Cooperoceras is a genus of the Tainoceratidae, which is part of the Tainocerataceae, characterized by and evolute shell with an open, perforate, umbilicus, sinuous ribs at maturity, and recurved hollow spines along the ventro-lateral shoulders. The flanks and venter are flattened, the flanks...
- †Copiceras
- †Coralloceras
- †Corbuloceras
- †Cornuella
Cornuella is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Corysoceras
- †Cosmonautilus
- †Cotteroceras
Cotteroceras is a proterocameroceratid from the Lower Ordovician of North America and Siberia characterized by a long straight and compressed shell with very short camerae and long body chamber. Sutures are straight and oblique, sloping dorsoventrally toward the apex. The siphuncle is large but...
- †Craftonoceras
- †Cranoceras
- †Crateroceras
- †Cryptocycloceras
Bogoslovskya is an extinct genus of actively mobile carnivorous cephalapod that lived in what would be Europe during the Silurian from 422.9—418.7 mya, existing for approximately .-Morphology:...
- †Cryptorthoceras
- †Ctenoceras
- †Cumberloceras
- †Cumingsoceras
Cummingsoceras is a barrandeoceroid genus within the Tarphycerida, included in the family Uranoceratidae. Its shell is a rapidly expanding gyrocone of about 1.5 narrowly separated whorls....
- †Curtoceras
Curtoceras is a genus in the tarphycerid family Trocholitidae found widespread in the late Early and Middle Ordovician of North America and northern Europe. Curtoceras has a shell that is gradually expanded, with half the fully mature body chamber divergent from the preceding volution. Whorl...
- †Cycloceras
Cycloceras is an extinct nautiloid cephalopod genus from the Carboniferous of Western Europe, of unknown affinity with the orthocerida -Taxonomy:...
- †Cyclolituites
- †Cyclopites
- †Cycloplectoceras
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from Bassleroceras or possibly from some member of the...
- †Cyclostomiceras
- †Cymatoceras
- †Cymatonautilus
- †Cyrtactinoceras
- †Cyrthoceratites
Cyrthoceratites is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Cyrtobaltoceras
Cyrtobaltoceras is an extinct cephalopod genus known from the upper Lower Ordovician Fort Cassin Formation at Valcour, N.Y. that's included in the Nautiloid family Baltoceratidae-Taxonomy:...
- †Cyrtoceras
Cyrtoceras is an extinct genus of oncoceridan nautiloid that lived from the middle Ordovician to the middle Devonian, in Africa, Europe, North America, and South America.-Sources:* Fossils by David Ward...
- †Cyrtoceratites
- †Cyrtocerina
- †Cyrtocheilus
- †Cyrtogomphoceras
- †Cyrtogomphus
- †Cyrtonybyoceras
Cyrtonybyoceras is a slightly exogastric member of the Wutinoceratidae, a family of actinocerids and probably derived from an earlier Wutinoceras . The shell of Cyrtonybyoceras is curved slightly upwardly and is slightly compressed. Sutures slope toward the aperture, from the dorsum to the venter...
- †Cyrtorizoceras
- †Cyrtospyroceras
- †Cyrtothoracoceras
D
- †Dakeoceras
Dakeoceras is a simple cyrtoconic ellesmeroceratid genus, all known species of which come from the Lower Canadian of North America....
- †Dalecarlioceras
- †Danaoceras
- †Danoceras
- †Danzikoceras
- †Dasbergoceras
- †Dawsonoceras
- †Dawsonocerina
Dawsonocerina is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Deckeroceras
- †Deiloceras
- †Deinoceras
- †Deiroceras
- †Deltoceras
- †Deltocymatoceras
- †Deltoidonautilus
- †Dentoceras
- †Desioceras
- †Devonocheilus
Devonocheilus is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Diademoceras
- †Diagoceras
- †Diaphoroceras
- †Diastoloceras
- †Dictyoceras
- †Diestoceras
- †Digenuoceras
- †Diodoceras
- †Diorugoceras
- †Discitoceras
Discitoceras is an extinct genus of nautiloid from the Lower Carboniferous....
- †Discoactinoceras
- †Discoceras
Discoceras, a member of the Trocholitidae in the Tarphycerida, not to be confused with Discosorus.Discoceras is characterized by closely coiled, gradually expanding shells with a subquadrate cross section, that may be ribbed or smooth. The sides are broadly rounded; the venter wide and slightly...
- †Discosorus
Discosorus , a genus of the Discosorida and member of the family Discosoratidae. Not to be confused with Discoceras. Discosorus consists of rapidly expanding endogastric brevicones, mostly known from isolated siphuncles composed of broadly expanded segments that increase rapidly in size. Septal...
- †Dnestroceras
- †Doleroceras
- †Dolorthoceras
- †Domatoceras
- †Dongshanoceras
- †Dowlingoceras
- †Drakonoceras
- †Duerleyoceras
- †Dunleithoceras
- †Dwightoceras
- †Dynatoceras
- †Dyscritoceras
- †Dzhinsetoceras
E
- †Eburoceras
- †Ecdyceras
- †Ectenoceras
- †Ectenolites
Small, slender, cylindrial members of the Ellesmeroceratidae that resemble small but proportionally narrower Ellesmeroceras. Septa, as typical for ellesmerocerids, are close spaced with shallow lobes on either flank. The body chamber is proportionally long, the shell itself slightly compressed...
- †Ectocycloceras
The Protcycloceratidae is an extinct family of slender, commonly annulate, members of the cephalopod order Ellesmerocerida that lived during the Early Ordovician...
- †Ectocyrtoceras
- †Edaphoceras
Edaphoceras is koninckioceratid genus and nautilid from the Mississippian of North America, named by Hyatt, 1884, with depressed whorls just in contact. The shell, as typical for the family, is evolute; whorl section is fusiform with broadly rounded venter and dorsum meeting at a narrow angle on...
- †Edenoceras
- †Ehlersoceras
Genera within the Oncoceratidae, a family within the nautiloid order Oncocerida are found in a few basic and distinct forms. among which are those that are slender in proportion. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are...
- †Eichwaldoceras
- †Eifeloceras
- †Ekwanoceras
- †Elaphoceras
- †Eldroceras
- †Eleusoceras
- †Elkanoceras
- †Ellesmeroceras
- †Ellinoceras
Ellinoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-See also:* Nautiloid** List of nautiloids...
- †Elpisoceras
- †Elrodoceras
- †Encoiloceras
Encoiloceras is a Tainoceratid genus, a nautiloid cephalopod in the order Nautilida that has been found in Upper Triassic sediments in the Alps and Hungary....
- †Endoceras
Endocerida is an extinct nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in its siphuncle.Endocerida comprises a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silurian . Their shells varied in form...
- †Endocycloceras
The Protcycloceratidae is an extinct family of slender, commonly annulate, members of the cephalopod order Ellesmerocerida that lived during the Early Ordovician...
- †Endodiscosorus
- †Endolobus
Endolobus is an extinct genus from the nautiloid order, Naulilida which includes Nautilus found living today. Endolubus is ncluded in the family Koninckioceratidae which is part of the superfamily Taintocerataceae...
- †Endoplanoceras
- †Endoplectoceras
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian...
- †Endorioceras
Endorioceras is an extinct genus of actively mobile carnivorous cephalapod of the family Baltoceratidae that lived in what would be North America during the Ordovician from 490—479 mya, existing for approximately .-Taxonomy:...
- †Endostokesoceras
- †Engorthoceras
Engorthoceratidae is a small family of Devonian orthocerids found in eastern North America , containing only the genus Engorthoceras.-Taxonomy:...
- †Enoploceras
Enoploceras is a Tainoceratid genus, a nautiloid cephalopod in the order Nautilida, known from Triassic sediments in Europe, India, Timor, and the state of Idaho....
- †Entimoceras
- †Eoclarkoceras
- †Eocyckistomiceras
- †Eocyrtoceras
- †Eodiaphragmoceras
- †Eoectenolites
- †Eorizoceras
The Graciloceratidae is a family of nautiloid cephalopods from the Middle and Upper Ordovician belonging to the Oncocerida, characterized by exogastric cyrtocones that expand slightly or moderately and have thin walled, orthochoantic marginal or subventral, tubular siphuncles The Graciloceratidae...
- †Eosomichelinoceras
Eosomichelinoceras is an extinct genus from the actively mobile carnivorous cephalapod family Baltoceratidae that lived in what would be Asia and South America during the Ordovician from 468—449 mya, existing for approximately .-Taxonomy:...
- †Eothinoceras
- †Eotrimeroceras
- †Eotripteroceras
Eotripteroceras is a smooth-shelled michelinocerin orthocerid from the middle Ordovician of the state of New York.The shell of Eotripteroceras is a depressed orthocone with the underside flatter than the upper . The siphuncle is below the center -as viewed in horizontal orientation- and is...
- †Ephippioceras
Ephippioceratidae is a family of clydonatilacean nautilids with shells as in the Liroceratidae but with sutures that have deep ventral and dorsal saddles...
- †Ephippiorthoceras
- †Epicymatoceras
- †Epidomatoceras
- †Epistroboceras
- †Eremoceras
- †Eridites
Eridites is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Eskimoceras
- †Esopoceras
- †Estonioceras
Estonioceras is an extinct genus of tarphyceridan nautiloid from the Ordovician of Europe.-Sources:* Dinosaur Encyclopedia by Jayne Parsons* Fossils by David Ward-External links:* in the Paleobiology Database...
- †Euciphoceras
- †Eucymatoceras
- †Eudoceras
Eudoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Euloxoceras
- †Euryrizoceras
- †Eurystomites
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from Bassleroceras or possibly from some member of the...
- †Eushantungoceras
- †Eusthenoceras
- †Eutrephoceras
- †Evlanoceras
- †Exochoceras
- †Exocyrtoceras
F
- †Faberoceras
Faberoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Fayettoceras
- †Flowerites
- †Floweroceras
- †Foersteoceras
- †Folioceras
Folioceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Foordiceras
- †Franklinoceras
Franklinoceras is an extinct cephalopod genus from the nautiloid order, Discosorida. Nautiloids comprise a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species....
- †Fremontoceras
- †Fusicoceras
G
- †Galtoceras
- †Gangshanoceras
- †Garryoceras
Garryoceras is an extinct genus, probably from the actively mobile carnivorous cephalapod order Orthocerida, that lived in what would be North America during the Late Ordovician, from 460.5—443.7 mya, existing for approximately .-Taxonomy:...
- †Gasconsoceras
- †Gaspocyrtoceras
- †Geisonoceras
- †Geisonocerina
Geisonocerina is an extinct genus from the carnivorous nautiloid cephalapod order Orthocerida that lived in what would be North America, Europe, and Asia during the Ordovician through Permian from 449—290 mya, existing for approximately .-Taxonomy:...
- †Geisonoceroides
- †Geitonoceras
- †Georgina
- †Germanonautilus
- †Glenisteroceras
- †Glossoceras
- †Glyptodendron
Glyptodendron is a Lower Silurian westonocerid characterized by compressed cyrtocones with a narrowly rounded dorsum and greatest width in the ventrolateral region. Sutures slope forward from the dorsum which is on the longitudinally concave side. The siphuncle is slightly ventral from the center....
- †Goldringia
- †Gomphoceras
- †Gonatocyrtoceras
- †Gonioceras
Gonioceras is an actinocerid with a broad, low shell; flattened ventrally, convexly rounded dorsally; top and bottom meeting at an acute angle along the sides. In most the shell is rather thin, especially along the lateral portion. The aperture is contracted...
- †Gonionaedyceras
The Naedyceras group is made up of three similar and closely related genera, Naedyceras, Gonionaedyceras, and Gyronaedyceras; three gyroconic members of the Brevicoceratidae, within the nautiloid order Oncocerida....
- †Gonionautilus
Gonionautilidae is a family in the nautilid superfamily Clydonautiliaceae that contains only the genus Gonionautilus, known from the Upper Triassic of Europe and North America....
- †Gorbyoceras
- †Gordonoceras
- †Gorgonoceras
The Lamellorthoceratidae is a family of fossil nautiloids in the Orthocerida, defined by Curt Teichert in 1961. The lamellorthoceratids are placed in the superfamily Orthocerataceae in the Treatise on Invertebrate Paleontology ....
- †Gouldoceras
- †Graciloceras
The Graciloceratidae is a family of nautiloid cephalopods from the Middle and Upper Ordovician belonging to the Oncocerida, characterized by exogastric cyrtocones that expand slightly or moderately and have thin walled, orthochoantic marginal or subventral, tubular siphuncles The Graciloceratidae...
- †Graftonoceras
- †Greenlandoceras
Greenlandoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Grimsbyoceras
- †Grypoceras
- †Gryponautilus
- †Grzegorzewskia
- †Guangyuanoceras
- †Guangyuanoceroides
- †Gyroceras
Gyroceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Gyronaedyceras
The Naedyceras group is made up of three similar and closely related genera, Naedyceras, Gonionaedyceras, and Gyronaedyceras; three gyroconic members of the Brevicoceratidae, within the nautiloid order Oncocerida....
- †Gzheloceras
H
- †Hadoceras
The Tripteroceratidae is a family of depressed, straight to slightly curved longiconic cephalopods from the middle and upper Ordovician with generally flattened venters and suborthochoantic to cyrtochoantitic, empty, siphuncles, tentatively included in the Oncocerida...
- †Halloceras
Halloceras is a gyroconic rotoceratid from the Lower Devonian of North America, with a subtriangular whorl section, narrow dorsum , divergent flanks, and broad, rounded venter , frills at various growth points, suture with shallow ventral and lateral lobes, and a small siphuncle near the...
- †Hardmanoceras
Hardmanoceras is a Tarphycerid genus belonging to the Trochilidae from the upper Lower Ordovician to possibly the lower Middle Ordovician, found in Western Australia. Hardmanoceras is like Discoceras but prominently ribbed and with a depressed whorl section. The body, or living, chamber is long,...
- †Harrisoceras
- †Haruspex
In Roman and Etruscan religious practice, a haruspex was a man trained to practice a form of divination called haruspicy, hepatoscopy or hepatomancy. Haruspicy is the inspection of the entrails of sacrificed animals, especially the livers of sacrificed sheep and poultry...
- †Haydenoceras
- †Hebetoceras
- †Hecatoceras
Hectoceras is a genus in the nautiloid cephalopod order Discosorida from the Upper Ordovician of Australia , known from a few isolated siphuncle specimens....
- †Hedstroemoceras
- †Helenites
- †Heloceras
- †Hemibeloitoceras
- †Hemichoanella
The Genus Hemichoanella is a small, extinct, orthoconic nautiloid cephalopod from the Lower Ordovician of Western Australia assigned to the orthoceratoid family, Baltoceratidae....
- †Hemicosmorthoceras
Geisonocerina is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be present day Europe during the Silurian to Devonian from 422.9—412.3 mya, existing for approximately .-Taxonomy:...
- †Hemiliroceras
- †Heminautilus
Heminautilus is an extinct Nautiloid genus from the nautilacean family Cymatoceratidae that lived during the early Cretaceous....
- †Hemiphragmoceras
- †Heracloceras
- †Hercoceras
- †Hercocyrtoceras
- †Hercoglossa
- †Hercoglossoceras
- †Herkimeroceras
- †Hesperoceras
Hesperoceras is an orthocerid cephalopod belonging to the subfamily Michelinoceratinae which comes from the lower Mississippian of New Mexico...
- †Hexagonites
Hexagonites is an extinct genus from the nautiloid order, Naulilida which includes the genus Nautilus found living in the tropical western Pacific. Hexagonites is included in the Family Tainoceratidae which makes up part of the superfamily Tainocerataceae Hexagonites is based on an incomplete,...
- †Hexameroceras
- †Hindeoceras
- †Hipparionoceras
- †Hiregiroceras
- †Hoeloceras
Hoeloceras is an extinct orthoconic nautiloid cephalopod from the upper Ordovician, generally included in the Actinocerida.Nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a couple of genera, Nautilus and Allonautilus.Hoeloceras,...
- †Holconautilus
Holconautilus is a Nautiloid genus from the family Tainoceratidae and order Nautilida, named by Mojsisovics, 1902, and known from Upper Triassic sediments in Europe and E Indies...
- †Holmiceras
Holmiceras is one of two ancestral lituitids from the late Early Ordovician . The other being Ancistroceras.Holmiceras begins with about 1.5 to 2 loosely coiled whorls followed by a rapidly expanding orthocone, much like Ancistroceras except for the apical whorls and that Holmiceras is known only...
- †Homaloceras
Homaloceras is an extinct nautiloid cephalopod from the Middle Devonian with a strongly curved shell, included in the nautilid family Centroceratidae....
- †Homoadelphoceras
- †Huaiheceras
- †Huanghuachangoceras
- †Huiaihecerina
- †Hunanoceras
- †Hunyuenoceras
- †Huronia
Huronia is an actinocerid genus included in the Huroniidae along with Discoactinoceras and Huroniella,. Huronia is characterized by long siphuncle segments with the free part of the connecting rings only slightly inflated and by a narrow central canal and strongly curved radial canals located in...
- †Huroniella
Huroniella is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Hysteroceras
I
- †Inclytoceras
- †Indonautilus
- †Inversoceras
J
- †Jangziceras
Jangziceras is a fossil nautiloid cephalopod from the Middle Silurian of southern China belonging to the Orthocerida incertae sedis, its familial association undetermined. The type is Jangziceras sichuanense Lai Chai-Geen...
- †Jaregoceras
- †Jasperoceras
The Trocholitidae are Tarphycerida with whorls in close contact as with the Tarphyceratidae, but in which the siphuncle, similar in structure, becomes dorsal. The Trocholitidae are derived from the Tarphyceratidae, perhaps from different tarphyceratids....
- †Jiagouceras
Jiagouceras is an early primitive cephalopod from the Upper Cambrian of China, assigned to the Plectronoceratidae. The shell is small, nearly straight with a slight endogastric curvature and compressed cross section...
- †Joachimoceras
Jaochimoceras is an orthoceroid cephalopod from the Silurian of Central Europe named by Baskov, 1960, and included in the Geisonoceratidae...
- †Joldagiroceras
- †Jolietoceras
Jolietoceras is a compressed, annulate, lituiconic nautiloid included in the derived Tarphycerid family, Uranoceratidae. The shell is gyroconic in the early stae, becoming straight and more rapidly expanded in the later. Sutures are straight and transverse...
- †Jonesoceras
- †Jovellania
Jovellania is an extinct prehistoric nautiloid genus 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.Jovellania was named...
- †Juvavionautilus
The Syringonautilidae comprise the last of the Trigonocerataceae and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. The Syringonautilidae, itself, is a strictly Triassic family, derived early in the Triassic...
K
- †Kadaroceras
- †Kallholnoceras
- †Karadzharoceras
- †Karoceras
- †Katageioceras
- †Kayoceras
- †Kentlandoceras
- †Keraiaceras
- †Kiaeroceras
- †Kijoceras
- †Kyminoceras
The Protcycloceratidae is an extinct family of slender, commonly annulate, members of the cephalopod order Ellesmerocerida that lived during the Early Ordovician...
- †Kinaschukoceras
- †Kindleoceras
- †Kionoceras
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...
- †Kitatites
- †Kladisoceras
- †Knightoceras
- †Kobyashiceras
Kobyashiceras is an extinct genus in the cephalopod order Actinocerida, from Lower Devonian marine sediments in Japan. The type and sole included species is Kobayashiceras gifuense. The generic name honors the late Dr. Teiichi Kobayashi who contributed greatly to the study of Paleozoic cephalopods...
- †Kochoceras
- †Konglungenoceras
- †Kophinoceras
- †Kosovoceras
Kosovoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Kotelnyoceras
- †Krykyloceras
- †Kummeloceras
- †Kundoceras
The Graciloceratidae is a family of nautiloid cephalopods from the Middle and Upper Ordovician belonging to the Oncocerida, characterized by exogastric cyrtocones that expand slightly or moderately and have thin walled, orthochoantic marginal or subventral, tubular siphuncles The Graciloceratidae...
- †Kyminoceras
L
- †Lambeoceras
Lambeoceras is a rather large actinocerid with a convexly lenticular cross section from the Upper Ordovician of North America, and the sole representative of the family Lambeoceratidae.-Morphological Description:...
- †Lamellorthoceras
The Lamellorthoceratidae is a family of fossil nautiloids in the Orthocerida, defined by Curt Teichert in 1961. The lamellorthoceratids are placed in the superfamily Orthocerataceae in the Treatise on Invertebrate Paleontology ....
- †Landeroceras
Landeroceras is a straight shelled cyrtogomphoceratid from the Middle Ordovician Big Horn dolomite of Wyoming.The shell of Landeroceras is a subcylindrical brevicone with the siphuncle on one side, determined as ventral. Siphuncle segments are short and well expanded into the chambers...
- †Laumontoceras
Laumonttoceras is a genus in oncocerid family Jovellaniidae from the lower Devonian of Europe characterized by uncompressed, moderately expanding, orthocones with a central siphuncle composed of cylindrical segments that are slightly contracted at the septal openings and which contain discrete,...
- †Laureloceras
Laureloceras is a genus of slender, smooth-shelled, cyrtoconic or gyroconic barrandeoceratids from the Middle Silurian of N Am. . Sutures are transverse but may form broad lateral lobes. The siphuncle is subventral - close to the convex side; necks are straight, connecting rings slightly expanded...
- †Lavaloceras
- †Lawrenceoceras
- †Lechritrochoceras
Lechritrochoceratidae is a family of derived tarphycerids from the middle and upper Silurian, once included in the now largely abandoned Barrandeocerida, which comprise dextrally torticonic genera with costate shells and ventrally displaced siphuncles. Offset coiling in low spired. Rate of...
- †Leonardoceras
- †Leuroceras
- †Leurocycloceras
Leurocycloceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be North America, Europe, and Asia during the Silurian from 443.7—418.7 mya, existing for approximately .-Morphology:...
- †Leurorthoceras
- †Leurotrochoceras
Lechritrochoceratidae is a family of derived tarphycerids from the middle and upper Silurian, once included in the now largely abandoned Barrandeocerida, which comprise dextrally torticonic genera with costate shells and ventrally displaced siphuncles. Offset coiling in low spired. Rate of...
- †Levisoceras
Levisoceras is an early Ordovician ellesmerocerid cephalopod.- Morphology :Levisoceras is a distinctive ellesmeroceratid that combines rapid expansion a strong endogastric curvature. The cross section is compressed with the height increasing more rapidly than the width. The siphuncle is ventral and...
- †Librovitschiceras
- †Linstroemoceras
- †Liroceras
Liroceras is the type genus of the clydonautiliacean family, Liroceratidae, and is characterized by a rapidly expanding, subglobular, nautiliconic shell with a reniform whorl section, small umbilicus, essentially straight sutures, and a siphuncle with a variable but not marginal position.Liroceras...
- †Lispoceras
- †Litoceras
Litoceras is a trocholitid genus that has been found the Lower and early Middle Ordovician of Newfoundland. Whorls in Litoceras have a broadly rounded cross section with the width greater than the height and somewhat resembles the tarphyceratid Pionoceras from the same time, except for the...
- †Litogyroceras
- †Lituites
Lituites is an extinct nautiloid genus from the Middle Ordovician and type for the Lituitidae, a tarphycerid family that in some more recent taxonomies has been classified with the orthocerids and listed under the order Lituitida...
- †Llanoceras
- †Lobendoceras
Lobendoceras is a proterocameraceratid with a rather large, moderately expanded, straight shell with a large marginal siphuncle in which sutures have a broad, deep, ventral lobe and septal necks are subholochoanitic to holochoanitic....
- †Loganoceras
Genera within the Oncoceratidae, a family within the nautiloid order Oncocerida are found in a few basic and distinct forms. among which are those that are slender in proportion. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are...
- †Lophoceras
Lophoceras is a Nautilid genus belonging to the tainoceratacean family, Koninckioceratidae, found in Lower Carboniferous sediments in Europe, and named by Hyatt, 1893. The shell of Lophoceras is evolute, large, with a slight impressed zone on the inner rim...
- †Lopingoceras
- †Lorieroceras
- †Lowoceras
- †Loxoceras
- †Lunanoceras
- †Lychnoceras
- †Lyckholmoceras
- †Lyecoceras
- †Lyrioceras
- †Lysagoroceras
- †Lysagoroceras
M
- †Maccoyoceras
- †Macrodomoceras
- †Macroloxoceras
Macroloxoceras is a large pseuorthocerid from the upper Devonian of Central Colorado and Southern New Mexico with features resembling those found inactinocerids....
- †Madiganella
- †Maelonoceras
- †Magdoceras
- †Mahoningoceras
- †Mandaloceras
Mandaloceratidae is a family in the nautiloid cephalopod order, Discosorida, from the Middle and Upper Silurian characterized by essentially straight, breviconic shells, most with a faintly exogastric shape produced by the profile of the body chamber...
- †Manitoulinoceras
- †Manjoceras
- †Mariceras
- †Mcqueenoceras
Mcqueenoceras is an early endocerid, a nautilus from the Ordovician period similar in overall form to Clitendoceras, from which it may have been derived. It lived during the later stages of the lower Ordovician. McQueenoceras, like Clitendoceras, has ventral siphuncle but the endocones are thicker...
- †Mecynoceras
- †Megadisocosorus
- †Megaglossoceras
Ephippioceratidae is a family of clydonatilacean nautilids with shells as in the Liroceratidae but with sutures that have deep ventral and dorsal saddles...
- †Megaloceras
- †Meikeloceras
- †Meitanoceras
- †Meloceras
- †Meniscoceras
Meniscoceras is a straight and slender Chazyan endocerid described by Rousseau Flower in 1941 The genus was originally included in the Proterocameroceratidae but later placed with its predecessor, Najaceras, in the Najaceratidae.The siphuncle in Mensicoceras is large with short septal necks and...
- †Menuthionautlis
- †Mericoceras
Mericoceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Europe during the Silurian to Devonian from 428.2—412.3 mya, existing for approximately .-Morphology:...
- †Mesaktoceras
- †Mesnaquaceras
- †Mesoceras
Mesoceras is a mid Silurian discosorid from central Europe named by Barrande in 1877, with a short, anteriorly contracted body chamber and an aperture that is a long transverse slit. . The cross section is slightly oval with the dorso-ventral dimension slightly less than the lateral...
- †Mesochasmoceras
- †Metabaltoceras
Microbaltoceras is an extinct genus of actively mobile carnivorous cephalapod of the family Baltoceratidae, essentially a Nautiloid, that lived in what would be North America during the Ordovician from 490—466 mya, existing for approximately .-Taxonomy:...
- †Metacoceras
Metacoceras is a nautilitoid cephalopod from the Upper Carboniferous and Permian, the shell of which is moderately evolute with a subquadrate whorl section, bearing nodes on the ventral or umbilical shoulders or both, but otherwise smooth. The siphuncle is small, subcentral and orthochoanitic...
- †Metactinoceras
- †Metaphragmoceras
- †Metarizoceras
- †Metarmenoceras
- †Metaspyroceras
- †Metastromatoceras
- †Metephippiorthoceras
- †Metrioceras
Metrioceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Miamoceras
- †Michelinoceras
Michelinoceras is the oldest known genus of the Michelinocerida, more commonly known as the Orthocerida, characterized by long, slender, nearly cylindrical orthocones with a circular cross section, long camerae, very long body chambers, and a central or near central tubular siphuncle free of...
- †Microbaltoceras
Microbaltoceras is an extinct genus of actively mobile carnivorous cephalapod of the family Baltoceratidae, essentially a Nautiloid that lived in what would be North America during the Ordovician from 490—479 mya, existing for approximately ....
- †Micronoceras
- †Millkoninckioceras
- †Mimolychnoceras
- †Minganoceras
- †Mitorthoceras
- †Mitroceras
- †Mixosiphonoceras
- †Mjandymoceras
- †Mnemoceras
- †Mojscaroceras
- †Mongoceras
Mongoceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Asia during the Silurian from 443.7—428.2 mya, existing for approximately .-Morphology:...
- †Monocyrtoceras
- †Monogonoceras
- †Monomuchites
- †Montyoceras
- †Mooreoceras
- †Moreauoceras
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from Bassleroceras or possibly from some member of the...
- †Mosquoceras
- †Mstikhinoceras
- †Muiroceras
- †Multicameroceras
- †Murchisoniceras
Murchisoniceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Europe during the Silurian from 418.7—412.3 mya, existing for approximately .-Morphology:...
- †Muriceras
- †Murrayoceras
Murrayoceras is a nautilid cephalopod included in the orthocerid family Baltoceratidae, wide spread in the Middle Ordovician of North America, characterized by a depressed orthoconic shell with a subtriangular cross section and flattened venter and a proportionally large verntral siphuncle, 0.15...
- †Myloceras
- †Mysterioceras
N
- †Naedyceras
The Naedyceras group is made up of three similar and closely related genera, Naedyceras, Gonionaedyceras, and Gyronaedyceras; three gyroconic members of the Brevicoceratidae, within the nautiloid order Oncocerida....
- †Najaceras
Najaceras is a genus of straight, slender endocerid known only from the Whiterockian age Oil Creek Limestone of Oklahoma, introduced and named by Rousseau Flower in 1971 and further described by him in 1976....
- †Nanno
- †Nassauoceras
Nassauoceras is a tetragonoceratid nautiloid from the Middle Devonian of Europe, the shell of which is evolute with a wide, deep umbilucus, slight dorsal impression, low arched venter, rounded ventral shoulders, and flanks that converge dorsally so as to produce a subtrigonal whorl section. Nodes...
- †Nautiloceras
Nautiloceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- Nautilus
Nautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...
- †Nebroceras
- †Neobistrialites
- †Neoceras
- †Neocycloceras
Neocycloceras is an extinct nautiloid genus included in the Pseudorthocerida that lived during the Late Devonian and Mississippian . Neoclycloceras is characterized by a slender, generally circular shell with slightly oblique,sinuous surficial annulations. Its sutures have dorsal and ventral...
- †Neocymatoceras
- †Neodiscosorus
- †Neodomatoceras
- †Neorthoceras
- †Neosichuanoceras
Neosichuanoceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Asia during the Silurian from 436.0—428.2 mya, existing for approximately .-Taxonomy:...
- †Nephriticeras
- †Nephriticerina
- †Neptunoceras
Neptunoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Neumatoceras
- †Nikenautilus
- †Nipageroceras
- †Nothoceras
- †Notocycloceras
The Protcycloceratidae is an extinct family of slender, commonly annulate, members of the cephalopod order Ellesmerocerida that lived during the Early Ordovician...
- †Nucites
- †Nybyoceras
Nybyoceras is an actinocerid genus assigned to the Armenoceratidae and similar to Armenoceras except for having a siphuncle close to the ventral side of the shell.-Morphology:...
O
- †Octamerella
Octamerella is an extinct prehistoric nautiloidgenus from the oncocerid family Hemiphragmoceratidae that lived in what is now Europe and North America during the Middle Silurian....
- †Oelandoceras
- †Offleyoceras
- †Ogygoceras
- †Ohioceras
Ohioceras is an extinct suborthochonic nautiloid from the Silurian of Ohio belonging to the orthoceroid family Kionoceratidae.Ohioceras is characterized by a slightly curved longiconic shell with a circular to slightly depressed cross section. The surface is lined with broad, low, longitudinal ribs...
- †Oligoceras
- †Oncoceras
- †Oneotoceras
- †Onyxites
- †Oocerina
Genera within the Oncoceratidae, a family within the nautiloid order Oncocerida are found in a few basic and distinct forms. among which are those that are slender in proportion. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are...
- †Oonoceras
Genera within the Oncoceratidae, a family within the nautiloid order Oncocerida are found in a few basic and distinct forms. among which are those that are slender in proportion. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are...
- †Ophidioceras
Ophidioceras is an alternate name for the Tarphycerid genus Ophioceras, which is known from the Upper Silurian of Europe and North America....
- †Ophioceras
- †Ophionautilus
Ophionautilus is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Oratoceras
- †Ordosoceras
- †Ormoceras
Ormoceras is an actinocerid genus of the family Ormoceratidae which is found in North America from the late Chazyan though the early Cincinnatian of the Middle and Upper Ordovician, but continued through the Devonian worldwide....
- †Orthoceras
Orthoceras is a genus of extinct nautiloid cephalopod. This genus is sometimes called Orthoceratites. Note it is sometimes misspelled as Orthocera, Orthocerus or Orthoceros ....
- †Orthocycloceras
Orthocycloceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Europe during the Silurian to Devonian from 428.2—412.3 mya, existing for approximately .-Morphology:...
- †Orthonybyoceras
- †Osbornoceras
Osbornoceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Ovoceras
- †Ovocerina
Mandaloceratidae is a family in the nautiloid cephalopod order, Discosorida, from the Middle and Upper Silurian characterized by essentially straight, breviconic shells, most with a faintly exogastric shape produced by the profile of the body chamber...
- †Oxfordoceras
- †Oxygonioceras
Oxygonioceras is a genus in the Oncocerid family, Brevicoceratidae, from the Middle Silurian of North America and Europe.Oxygonioceras, named by Foeste, 1925, has a loosely coiled, dextrally torticonic shell with a rounded dorsum on the inside of the spiral and an angular or subangular venter on...
- †Oxynautilus
The Syringonautilidae comprise the last of the Trigonocerataceae and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. The Syringonautilidae, itself, is a strictly Triassic family, derived early in the Triassic...
P
- †Pachendoceras
- †Pachtoceras
- †Pakrioceras
- †Palaeocycloceras
Palaeocycloceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Asia during the Silurian from 490—460.5 mya, existing for approximately .-Morphology:...
- †Palaskensis
- †Palelialia
Palelialia is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Palmeroceras
- †Pancornus
Pancornus is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Pantoioceras
- †Paquettoceras
- †Paracenoceras
- †Paracleistoceras
- †Paraconradoceras
- †Paractinoceras
- †Paracyclostomiceras
- †Paracymatoceras
- †Paradakeoceras
Paradakeoceras is an early Ordovician cephalopod belonging to the nautiloid order Ellesmerocerida.- Morphology :The shell of Paradakeoceras is an expanding endogastric cyrtocone with the siphuncle situated near the shell's concave margin....
- †Paradiscoceras
- †Paradnatoceras
Paradnatoceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Asia during the Ordovician from 479—460.5 mya, existing for approximately .-Morphology:...
- †Paradomatoceras
- †Parakionoceras
Parakionoceras is an extinct nautiloid that lived during the Silurian and Devonian in what is now Europe; included in the orthoceratoid family Kionoceratidae in the Treatise part K, 1964 but removed to the Arionoceratidae in Kröger 2008....
- †Paraloxoceras
Paraloxoceras is a straight shelled, orthoconic, nautiloid cephalopod, now extinct, that lived during the Early Carboniferous. Fossils have been found in Europe and central Asia; the type, P. konincki, named by Flower, came from Belgium....
- †Paramecynoceras
- †Parametacoceras
- †Paramooreoceras
- †Paranautilus
Paranautilus is a genus of the Nautiloid family Liroceratidae with a very involute, moderately globular, smooth shell. The venter, at the outer rim, is arched, grading into broadly convex flanks. The dorsom, on the inner rim, is deeply impressed. Septa a close spaced, with slightly sinuous sutures...
- †Parapalaeoceras
- †Paraphragmites
- †Paraplectronoceras
Paraplectronoceras is a very early nautiloid from the middle Late Cambrian, named by Chen and Qi, 1979, type species Paraplectronoceras pyriforme, for small, endogastrically curved forms found in the upper Yenchou and Wanwankou members of the Fengshan Formation of northeastern China.The shell of...
- †Pararhiphaeoceras
- †Pararineceras
- †Parascoceras
- †Parasphaerorthoceras
Parasphaerorthoceras is an extinct orthocerid cephalapod genus, a nautiloid, that lived in what would be Europe and north Africa during the Silurian from 422.9—418.1 mya, having existed for approximately .-Taxonomy:...
- †Parastenopoceras
- †Paratrematoceras
- †Parawestonoceras
- †Parevlanoceras
- †Paroocerina
Genera within the Oncoceratidae, a family within the nautiloid order Oncocerida are found in a few basic and distinct forms. among which are those that are slender in proportion. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are...
- †Parormoceras
- †Parryoceras
- †Pectinoceras
- †Peismoceras
Lechritrochoceratidae is a family of derived tarphycerids from the middle and upper Silurian, once included in the now largely abandoned Barrandeocerida, which comprise dextrally torticonic genera with costate shells and ventrally displaced siphuncles. Offset coiling in low spired. Rate of...
- †Pelagoceras
- †Pentameroceras
Pentameroceras is a straight to slightly exogastric breviconic oncocerid from the middle Silurian of North America and Europe belonging to the Trimeroceratidae....
- †Perimecoceras
Perimecoceras is a nothoceratid, nautilitoid order oncocerida, with a slowly expanding, compressed, cyrtoconic shell, known from the Upper Silurian of central Europe....
- †Perioidanoceras
- †Peripetoceras
Peripetoceras is a genus in the Clydonautilacean family, Liroceratidae. It can be recognized by its smooth, involute shell with a deep small umbilicus with rounded shoulders and steep convex wall; whorl section with flattened venter, rounded ventral shoulders and convergent slightly convex flanks;...
- †Permoceras
Permoceras, the sole member of the Permoceratidae, is a coiled nautiloid with a smooth, compressed involute shell, whorls highter 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...
- †Permodomatoceras
- †Permonautilus
Permonautilus is an extinct nautilid 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...
- †Perunautilus
- †Petryoceras
- †Phacoceras
- †Phaedrysmocheilus
- †Phloioceras
- †Phragmoceras
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian...
- †Phragmocerina
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian...
- †Phthanoncoceras
- †Physioceras
- †Pictetoceras
- †Piersaloceras
The Graciloceratidae is a family of nautiloid cephalopods from the Middle and Upper Ordovician belonging to the Oncocerida, characterized by exogastric cyrtocones that expand slightly or moderately and have thin walled, orthochoantic marginal or subventral, tubular siphuncles The Graciloceratidae...
- †Pilotoceras
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from Bassleroceras or possibly from some member of the...
- †Pionoceras
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from Bassleroceras or possibly from some member of the...
- †Piratoceras
- †Plagioceras
- †Plagiostomoceras
Plagiostomoceras is an orthocerid cephalopod from the lower Paleozoic of Europe and Australia.Shells of Plagiostomoceras are long slender orthocones with circular to slightly depressed cross sections. Sutures are straight or slightly oblique and may have faint lateral lobes. The siphuncle is...
- †Planetoceras
- †Platyconoceras
- †Plectoceras
- †Plectolites
- †Pleuronautilus
Pleuronautilus is a Nautiloid genus; family Tainoceratidae, order Nautilida. The shell is evolute, discoidal; whorl section subquadrade, flanks generally straight but may converge toward the venter. Inner flanks have course ribbing, outer have rows of nodes. Sutures have shallow ventral,...
- †Pleuroncoceras
- †Pleurorthoceras
Pleurorthoceras is an orthocerid cephalopod from the Upper Ordovician of North America . The shell externally is like that of Michelinoceras in being long and slender with a circular cross section. It differs in having a subcentral siphuncle with somewhat inflated segments.-References:* Sweet,...
- †Plicatoceras
- †Plummeroceras
- †Podoliceras
- †Polydesmia
- †Polyelasmoceras
- †Polygrammoceras
Polygrammoceras is an orthoconic nautiloid that lived during the period from the middle Ordovician to the early Devonian in what is now North America and Eurasia....
- †Poterioceras
- †Poteriocerina
- †Potoceras
- †Pristeroceras
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian...
- †Probillingsites
- †Proclydonautilus
- †Procymatoceras
- †Projovellania
Projovellania is an extinct nautiloid cephalopod belonging to the oncocerid family Jovellaniidae found in mid Silurian sediments in Europe. The shell is a longiconic cyrtocone, like that of Jovellania or Mixosiphonoceras, except for being compressed rather than depressed.- References :* Sweet W.C....
- †Proteoceras
- †Proterocameroceras
Proterocameroceras is an early Endocerid from the upper Lower Ordovician belong to the Proterocameroceratidae, characterized by a rather large, straight, longiconic shell, short chambers, generally straight sutures, and large ventral siphuncle with short septal necks, thick complex connecting...
- †Protobactrites
Protobactrites is an extinct nautiloid cephalapod belonging to the Orthoceratoidea that lived in what would be Europe and Asia during the Ordovician and Silurian from 466–421.3 mya, existing for approximately .-Taxonomy:...
- †Protocycloceras
The Protcycloceratidae is an extinct family of slender, commonly annulate, members of the cephalopod order Ellesmerocerida that lived during the Early Ordovician...
- †Protokionoceras
- †Protophragmoceras
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian...
- †Pselioceras
- †Pseudactinoceras
Pseudactinoceras is an extinct nautiloid cephalopod included in the order Pseudorthocerida and the namesake of the family Pseudactinoceratidae .-Description:...
- †Pseudaganides
- †Pseudancistroceras
- †Pseudaturoidea
- †Pseudendoceras
- †Pseudobolloceras
- †Pseudobrevicoceras
Pseudobrevicoceras is an extinct nautilitoid cephalopod genus in the order Oncocerida. The familial position is undetermined.Externally Pseudobrevicoceras resembles Brevicoceras, an oncocerid in the Brevicoceratidae, in having a curved, expanded, breviconic phragmocone with straight, transverse...
- †Pseudocatastroboceras
- †Pseudocenoceras
- †Pseudocycloceras
- †Pseudocyrtoceras
- †Pseudogomphoceras
Mandaloceratidae is a family in the nautiloid cephalopod order, Discosorida, from the Middle and Upper Silurian characterized by essentially straight, breviconic shells, most with a faintly exogastric shape produced by the profile of the body chamber...
- †Pseudokionoceras
- †Pseudonautilus
- †Pseudophacoceras
- †Pseudophragmoceras
- †Pseudorthoceras
- †Pseudostenopoceras
- †Pseudotemnocheilus
- †Pseudotemperoceras
Pseudotemperoceras is an extinct nautiloid cephalapod belonging to the Orthocerida from the far eastern part of the Russian Federation that lived during the Triassic from 249.7—245 mya, existing for approximately .-Taxonomy:...
- †Pseudotitanoceras
- †Psiaoceras
- †Ptenoceras
- †Ptyssoceras
- †Purmanarcoceras
- †Pycnoceras
- †Pyramidoceras
- †Pythonoceras
Q
- †Quebecoceras
Quebecoceras is an extinct genus from the nautiloid order Ellesmerocerida that lived during the Gasconadian Stage at the beginning of the Early Ordovician....
R
- †Radoceras
Radoceras is an extinct prehistoric nautiloid genus from the Paleozoic included in the order Discosorida-References:* * Sepkoski, J.J. Jr. 2002. A compendium of fossil marine animal genera. D.J. Jablonski & M.L. Foote . Bulletins of American Paleontology 363: 1–560....
- †Ramussenoceras
- †Rangeroceras
Rangeroceras is an extinct nautiloid cephalopod genus that lived in what is now western North America during the latter part of the Early Ordovician....
- †Raphanites
- †Rasmussenoceras
The Tripteroceratidae is a family of depressed, straight to slightly curved longiconic cephalopods from the middle and upper Ordovician with generally flattened venters and suborthochoantic to cyrtochoantitic, empty, siphuncles, tentatively included in the Oncocerida...
- †Rayonnoceras
Rayonnoceras is an extinct cephalopod genus that lived around 325 million years ago during the Carboniferous which although resemble earlier actinocerids are now though to belong to the Pseudorthocerida...
- †Rectseptoceras
- †Redpathoceras
- †Reedsoceras
Reedsoceras is a large member of the discosorid family Westonoceratidae from the middle and upper Ordovician of North America....
- †Reticycloceras
- †Rhabdiferoceras
Rhabdiferoceras is an extinct orthocerid genus belonging to the Baltoceratidae that lived in what would be North America during the Cassinian Stage at the end of the Early Ordovician, existing for approximately two million years from about 474 -472 mya....
- †Rhabdites
Rhabdites is an extinct orthocerid genus, a kind of straight-shelled nautiloid cephalopod.-References:* -Paleobio database.* Sepkoski, J.J. Jr. 2002. A compendium of fossil marine animal genera. Bulletins of American Paleontology 363: 1–560....
- †Rhadinoceras
- †Rhiphaeoceras
- †Rhiphaeonautilus
- †Rhipsites
- †Rhomboceras
- †Rhomboceras
- †Rhynchoceras
- †Rhynchorthoceras
Rhynchorthoceras is a Middle Ordovician genus characterized by a rapidly expanded, weakly annulate orthocone, like the orthoconic section of Ancistroceras, but with only a curved, cyrtoconic apex instead of juvenile whorls....
- †Richardsonoceras
Genera within the Oncoceratidae, a family within the nautiloid order Oncocerida are found in a few basic and distinct forms. among which are those that are slender in proportion. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are...
- †Rineceras
Rhineceras is an extinct genus from the nautilid family Trigonoceratidae which is part of the Trigonocerataceae, that lived during the Mississippian Period in the late Paleozoic....
- †Ringoceras
The Graciloceratidae is a family of nautiloid cephalopods from the Middle and Upper Ordovician belonging to the Oncocerida, characterized by exogastric cyrtocones that expand slightly or moderately and have thin walled, orthochoantic marginal or subventral, tubular siphuncles The Graciloceratidae...
- †Rioceras
Rioceras is an extinct orthocerid cephalapod genus of the family Baltoceratidae that lived in what would be North America during the Early Ordovician from 480—472 mya, existing for approximately 8 million years.-Taxonomy:...
- †Rizoceras
- †Robsonoceras
- †Romingoceras
Genera within the Oncoceratidae, a family within the nautiloid order Oncocerida are found in a few basic and distinct forms. among which are those that are slender in proportion. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are...
- †Ropaloceras
- †Roussanoffoceras
- †Rudolfoceras
The Protcycloceratidae is an extinct family of slender, commonly annulate, members of the cephalopod order Ellesmerocerida that lived during the Early Ordovician...
- †Ruedemannoceras
- †Ruthenoceras
Ruthenoceras is a conical Cambrian fossil originally classified as a cephalopod, but which is too poorly preserved for a classification to be upheld....
- †Rutoceras
S
- †Sactoceras
Sactoceras is an extinct nautiloid cephalopod that lived during the Ordovician and Silurian in what would become North America, Europe, and Asia.-Taxonomy:...
- †Sactorthoceras
Sactorthceras is an orthoceratoid genus known from the Middle Ordovician of eastern North America , Norway and Korea and is the type genus of the Sactorthoceratidae....
- †Saffordoceras
Genus Saffordoceras is an actinoceratid from the Middle Ordovician, found in eastern North America, characterized by a flattened venter; sutures with broad, deep ventral lobes and narrow lateral saddles; and subventral siphuncle with segments decreasing from about 0.3 to less than 0.2 the shell...
- †Savageoceras
The genus Savageoceras is a barrandeoceratid first known from the Middle Silurian of Illinois consisting of rapidly enlarging, depressed cyrtocones with a trapazoidal section; ventral side wider and flatter than dorsal; sides converging on dorsum. Sutures have slight lateral and ventral lobes and...
- †Sceptrites
Sceptrites is an orthoceratoid genus contained within the pseudorthocerid family Spyroceratidae known by its slightly compressed, possibly endogastrically curved, cyrtoconic shell. Sceptrites has been found in Devonian sediments in Ohio and N.Y...
- †Schroederoceras
- †Schuchertoceras
- †Scofieldoceras
- †Scyphoceras
- †Seelyoceras
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from Bassleroceras or possibly from some member of the...
- †Selenoceras
Selenoceras is an extinct nautiloid genus named by Zhuravleva , assigned to the Discosorida. Discosorids constitute an order of shelled cephalopods with siphuncle segments that are zoned longitudinally and connecting rings that typicallly wrap around the septal necks, re-enforcing the septal...
- †Selkirkoceras
- †Shamattawaceras
- †Shantungendoceras
Shantungendoceras is a conical Tremadocian fossil originally classified as a cephalopod, but which is too poorly preserved for a classification to be upheld....
- †Shideleroceras
- †Shikhanoceras
- †Sholakoceras
Sholakoceras is an extinct nautiloid cephalopod from the Lower Permian of southern Russia, included in the Tainoceratacean family Rhiphaeoceratidae,. The shell of Shalakoceras is evolute with a perforate umbilicus. Whorl sections are subquadrate with the ventral and lateral sides flattened and...
- †Shumardoceras
- †Shuranoceras
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, slowely enlarging orthoconic shellwith a ventral submarginal siphuncle composed of complrex...
- †Siberioceras
Siberioceras is an extinct orthocerid genus of uncertain affinity defined by Zhuravleva . Orthocerids are prehistoric shelled cephalopods included in the mostly orthoconic nautiloid superorder Orthoceratoidea.-References:...
- †Siberionautilus
- †Sibyllonautilus
- †Sichuanaceras
- †Sigmocycloceras
Sigmocycloceras is a nautiloid cephalopod discovered in the Middle Ordovician of Korea, said to be similar to Sactorthoceras, and included in the Sactorthoceratidae, but unique in being longitudinally sigmoid and sculpted with transverse annuli....
- †Simardoceras
Simardoceras is a genus in the discosorid family Westonoceratidae from the Middle Ordovician of Quebec.The shell of Simardoceras is a moderately expanding exogastric cyrtocone, said to resemble a rather large Oncoceras, but with a siphuncle that is definitely discosorid. The venter is almost...
- †Simorthoceras
- †Simplicioceras
- †Sinclairoceras
Sinclairoceras is a nautiloid cephalopod in the discosorid family Westonoceratidae from the Middle Ordovician Simard Limestone of Quebec. The shell is a compressed exogastric brevicone with venter narrowly and dorsum broadly rounded. The dorsum, at the upper surface, is only slightly concave...
- †Sinoceras
Sinoceras is an extinct nautilid genus from China included in the family Orthoceratidae that lived during the period from perhaps the middle Ordovician to as late as perhaps the Devonian....
- †Sinolebetoceras
- †Slocomoceras
- †Smileoceras
Smileoceras is an extinct prehistoric nautiloid genus named by Zhurableva, 1972, included in the Discosorida.-References:*...
- †Smithvilloceras
- †Soakinautilus
- †Solenochilus
Solenochilus, type genus of the Solenochildae 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...
- †Somalinautilus
- †Sophoceras
- †Spanioceras
Spanioceras is an extinct nautiloid cephalopod genus belonging to the order Oncocerida, which is thought to have given rise to the Nautilida which includes the living Nautilus.-References:*...
- †Sphooceras
- †Sphyradoceras
- †Spondeioceras
- †Spyroceras
Spyroceras is pseudorthocerid genus from the Devonian of North America and Europe, defined by Hyatt in 1884. Pseudorthocerids are a kind of orthocertaoid, a taxonomic group within the Nautiloidea...
- †Stagonites
- †Standardoceras
- †Staufferoceras
- †Stearoceras
Stearoceras is an extinct prehistoric nautiloid genus from the Lower Pennsylvanian - Lower Permian with a fair worldwide distribution....
- †Stemtonoceras
- †Stenogomphoceras
- †Stenopoceras
- †Stenzeloceras
- †Stereoplasmoceras
- †Stereospyroceras
- †Stereotoceras
Stereotoceras is a Middle_ and Upper Devonian genus in the oncocerid family Brevicoceratidae that formed a smooth, depressed, gyroconic shell with the dorsum much flatter that the venter. Sutures are straight ventrally but have dorsal lobes. Growth lines outline a ventral hyponomic sinus but are...
- †Sthenoceras
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian...
- †Stokesoceras
- †Stolbovoceras
- †Strandoceras
Strandoceras is a stronly curved cyrtogomphoceratid with a laterally compressed cross section from the middle and upper Ordovician of Northern Europe; Estonia, Norway, the U.K....
- †Streptoceras
Streptoceras is a genus in the extinct oncocerid family Acleistoceratidae that plied the shallow sea floor from the Middle Silurian to the Middle Devonian...
- †Striacoceras
- †Strionautilus
- †Strobiloceras
- †Stroboceras
Stroboceras is an extinct nautiloid named by Hyatt in 1884 that's included in the nautilid family Trigonoceratidae; the group that have rise to the Nautilidae which includes the living Nautilus....
- †Stroggyloceras
- †Stromatoceras
- †Strophiceras
Strophiceras is an extinct cephalopod genus from the Order Nautilida, which includes, in a separate family, Nautilus and Allonautilus....
- †Styrionautilus
- †Subclymenia
- †Subspyroceras
- †Subvestinautilus
Subvestinautilus is an evolute koninckioceratid genus, order Nautilida, with a depressed, trapezoidal whorl section. The venter is broadly rounded, ventrolateral shoulders sharply rounded, flanks flattened and converging toward a narrow rounded dorsum. In early growth stages a keel forms on the...
- †Suttonoceras
- †Sycoceras
- †Synetoceras
- †Syringoceras
The Syringonautilidae comprise the last of the Trigonocerataceae and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. The Syringonautilidae, itself, is a strictly Triassic family, derived early in the Triassic...
- †Syringonautilus
The Syringonautilidae comprise the last of the Trigonocerataceae and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. The Syringonautilidae, itself, is a strictly Triassic family, derived early in the Triassic...
- †Syrionautilus
- †Syrreghmatoceras
- †Systrophoceras
Lechritrochoceratidae is a family of derived tarphycerids from the middle and upper Silurian, once included in the now largely abandoned Barrandeocerida, which comprise dextrally torticonic genera with costate shells and ventrally displaced siphuncles. Offset coiling in low spired. Rate of...
T
- †Tainionautilus
Tainonautilus is an extinct coiled cephalopod that lived during the Permian and Early Triassic which is included in the nautiloid family Tainoceratidae....
- †Tainoceras
Tainoceras is an extinct coiled cephalopod that live during the later part of the Paleozoic and Triassic, that belongs to the nautiloid family Tainoceratidae....
- †Tajaroceras
Tejaroceras is an extinct slender cephalopod from the uppermost Lower Ordovician of western North America, belonging to the Orthocerid family Troedssonellidae....
- †Talattoceras
- †Tambegiroceras
- †Tanchiashanites
- †Tanycameroceras
- †Taoqupoceras
- †Tarphyceras
Tarphyeras is a genus of tarphyceratid with whorls rounded in cross section, having a deeply impressed dorsum and a ventral to subcentral siphuncle, known from the Lower Ord of North America...
- †Tartaroceras
- †Taskanoceras
- †Taxyceras
- †Teichertia
- †Teichertoceras
Teichertoceras is a discosorid genus in the family Westonoceratidae characterized by an endogastric curvature to the early portion of the phragmocone....
- †Temnocheilus
- †Temperoceras
Temperoceras is an orthoconic nautiloid cephalopod named by Barskov in 1960 that lived in what is now north Africa, Europe, and Asia during the early Paleozoic.-Taxonomy:...
- †Tetragonoceras
Tetragonoceras is an extinct prehistoric nautiloid genus from the nautilid family Tetragonoceratidae that lived during the Middle Devonian, found in Canada....
- †Tetrameroceras
- †Tetranodoceras
- †Tetrapleuroceras
Tetrapleuroceras is an extinct prehistoric nautiloid from the Lower Permian of the Urals in Russia.Tetrapleuroceras is one of two genera that Shimianky combined as the Neptunoceratidae in 1957, the other being Neptunoceras...
- †Thaymastoceras
- †Therioceras
- †Theskeloceras
- †Thoracoceras
Thoracoceras is an extinct orthocerid genus from the family Kionoceratidae characterized by orthoconic shells marked by prominent longitudinal rounded grooves separated by angular ridges, each which has a single row of blunt spines along its apex, and having a small submarginal...
- †Threaroceras
- †Thrincoceras
- †Thuringionautilus
Thuringionautilus is a large, moderately involute, nautiloid from the nautilid family Tainoceratidae. The whorl section is subquadrate, flanks slightly convex, venter broad with a median furrow. Ventral shoulders, narrowly rounded to subangular; umbilical shoulders, broadly rounded. Longitudinal...
- †Tienoceras
Tienocerasis an extinct orthoceratoid genus from the Permian of China . Orthoceratoids are slender conical or near cylindrial, orthoconic, nautiloid cephalopods from the Paleozoic...
- †Tirolonautilus
- †Titanoceras
Titanoceras is an extinct genus in the nautiloid order Nautilida from the Pennsylvanian and Lower Permian of North America and Western Australia....
- †Tithonoceras
Tithonoceras is a genus of nautiloid cephalopod from the Upper Jurassic found in the Crimea, belonging to the nautilacean family Paracenoceratidae....
- †Tofangoceras
- †Tomponautilus
- †Torquatoceras
- †Trachynautilus
- †Tragoceras
- †Trematoceras
Trematoceras is an orthoconic nautiloid cephalopod from the Upper Triassic of Europe and Asia named by Eichwald in 1851.-Taxonomy:Trematoceras is included in the Michelinoceratinae, a subfamily of the Orthoceratidae-Morphology:...
- †Trematodiscus
- †Tretoceras
Tretoceras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Europe during the Ordovician and Silurian from 466—460.5 mya, existing for approximately .-Taxonomy:...
- †Triboloceras
Triboloceras is the name given to an extinct nautiloid genus from the Lower Carboniferous , 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,...
- †Trigonoceras
Trigonoceras is an extinct prehistoric nautiloid genus from the nautilid family Trigonoceratidae that lived during the Early Carboniferous in what is now western Europe....
- †Trilacinoceras
- †Trimeroceras
- †Tripleuroceras
- †Triplooceras
- †Tripteroceras
The Tripteroceratidae is a family of depressed, straight to slightly curved longiconic cephalopods from the middle and upper Ordovician with generally flattened venters and suborthochoantic to cyrtochoantitic, empty, siphuncles, tentatively included in the Oncocerida...
- †Tripterocerina
The Tripteroceratidae is a family of depressed, straight to slightly curved longiconic cephalopods from the middle and upper Ordovician with generally flattened venters and suborthochoantic to cyrtochoantitic, empty, siphuncles, tentatively included in the Oncocerida...
- †Tripteroceroides
Tripteroceroides is a pseudorthocerid from the Lower Carboniferous belonging to the family Spyroceratidae . Pseudorthocerids are nautiloid cephalopods with expanded siphuncle segments included in the superorder Orthoceratoidea....
- †Trispectes
Trispectes is an extinct prehistoric nautiloid genus belonging to the Orthocerida, a variety of mostly straight-shelled cephalopods.-References:* *...
- †Tritonoceras
- †Trochoceras
Trochoceras is a trochoidally coiled nautiloid cephalopod placed in the nautilid family Rutoceratidae that lived during the Middle and Late Devonian in what is now central Europe....
- †Trochodictyoceras
Lechritrochoceratidae is a family of derived tarphycerids from the middle and upper Silurian, once included in the now largely abandoned Barrandeocerida, which comprise dextrally torticonic genera with costate shells and ventrally displaced siphuncles. Offset coiling in low spired. Rate of...
- †Trocholites
Trocholites is a tarphycerid genus in the fa mily Trocholitidae from the Middle and Upper Ordovician with a gradually expanding, weakly ribbed shell; whorls in contact, dorsum slightly impressed; cross section depressed, venter and sides rounded; siphuncle close to but not at the dorsal margin.The...
- †Trocholitoceras
The Trocholitidae are Tarphycerida with whorls in close contact as with the Tarphyceratidae, but in which the siphuncle, similar in structure, becomes dorsal. The Trocholitidae are derived from the Tarphyceratidae, perhaps from different tarphyceratids....
- †Troedssonella
- †Troedssonoceras
- †Troostoceras
- †Tshingizoceras
- †Tubiferoceras
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian...
- †Tumidoceras
- †Tumidonautilus
- †Tunguskoceras
- †Turnoceras
Turnoceras is Devonian cephalopod belonging to the oncocerid family Nothoceratidae. Its shell is a broadly expanding exogastric cyrtocone with a flattened dorsum -on the inner concave side, unconstricted aperture, no hyponimic sinus, and ventral siphuncle -on the outer, convex side- composed of...
- †Turoceras
- †Tuyloceras
- †Tylodiscoceras
- †Tylonautilus
Tylonautilus is an extinct genus in the nautiloid order Nautilida from the Lower Carboniferous of Europe and Permian of Japan.Tylonautilus has a coiled shell with a subquadrate whorl section, evolutely coiled with all whorls showing...
- †Tylorthoceras
- †Tyrioceras
U
- †Ukhtoceras
- †Uloceras
- †Ulrichoceras
Ulrichoceras is recognised as the basal cyrtogomphoceratid genus, which is the source for the rest of the Cyrtogomphoceratidae as well as for the Westonoceratidae...
- †Umbeloceras
Mandaloceratidae is a family in the nautiloid cephalopod order, Discosorida, from the Middle and Upper Silurian characterized by essentially straight, breviconic shells, most with a faintly exogastric shape produced by the profile of the body chamber...
- †Ungulites
Ungulites is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Uralorthoceras
- †Uranoceras
Uranoceras is a barrandeocerid genus from the Middle Silurian belonging to the family Uranoceratidae, characterized by its loosely coiled, gyroconic shell of 1.5 to 2 subquadrate whorls....
- †Urtasymoceras
V
- †Valcouroceras
- †Valhallites
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 Koninkioceratidae, a family in the Tainoceratacea, a nautilid superfamily...
- †Valhalloceras
- †Vasalemmoceras
- †Vassaroceras
- †Vaupelia
- †Venatoroceras
- †Veneficoceras
Veneficoceras is a member of the rod-bearing Baltoceratidae, an extinct cephalopod family with characteristics of the orthoceratoid Dissidocerida, found in Cassinianage, Lower Ordovician, limestone in western Utah....
- †Ventroloboceras
- †Vericeras
Vericeras is an extinct genus of actively mobile carnivorous cephalapod, essentially a Nautiloid, that lived in what would be Europe during the Silurian from 421—418.7 mya, existing for approximately .-Morphology:...
- †Verticoceras
- †Vertorhizoceras
- †Vespoceras
Mandaloceratidae is a family in the nautiloid cephalopod order, Discosorida, from the Middle and Upper Silurian characterized by essentially straight, breviconic shells, most with a faintly exogastric shape produced by the profile of the body chamber...
- †Vestinautilus
- †Virgaloceras
- †Virgoceras
W
- †Wadeoceras
- †Walcottoceras
- †Wardoceras
Wardoceras is an extinct nautiloid genus from the late Early Ordovician of Western Utah, assigned to the orthocerid family, Michelinoceratidae...
- †Weberoceras
- †Weishanhuceras
- †Welleroceras
- †Wellsoceras
Wellsoceras is a tetragonoceratid that starts off with an evolute shell in which whorls are in contact, but has a mature living chamber that diverges and becomes free. The whorl section is slightly wider than high and is faintly subquadrangular. Flanks are slightly convex and tend to comverge...
- †Westonoceras
Westonoceras is an extinct nautiloid genus from the Discosorida that lived during the Middle and Late Ordovician that has been found in North America, Greenland, and Northern Europe...
- †Whiteavesites
- †Whitfieldoceras
- †Wichitoceras
The Trocholitidae are Tarphycerida with whorls in close contact as with the Tarphyceratidae, but in which the siphuncle, similar in structure, becomes dorsal. The Trocholitidae are derived from the Tarphyceratidae, perhaps from different tarphyceratids....
- †Williamsoceras
Williamsoceras is an endocerid that Rousseau Flower added to his Allotrioceratidae on the basis of having a vertical partition within the siphuncle, known as a ventral process, with inter-connecting tubule-like structures along its margin where intercepted by endocones...
- †Wilsonoceras
- †Winnipegoceras
Winnipegoceras is an extinct nautiloid genus from the Ordovician belonging to the Order Discosorida.-Phylogeny:Winnipegoceras is included in the discosorid family Westonoceratidae and is derived from Westonoceras...
- †Wissenbachia
Wissenbachia is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
- †Wolungoceras
- †Woosteroceras
- †Worthenoceras
- †Wutinoceras
Wutinoceras, orthoconic actinocerids with ventral siphuncles composed of broadly expanded segments.and the type genus of the Wutinoceratidae. -Distinguishing Characters:...
X
- †Xainzanoceras
Xainzanoceras, defined by Chen, 1987, is a nautiloid cephalopod from the Upper Ordovician of China, assigned to the tarphyceratid family Lituitidae. The type, Xainzanoceras xizangense Chen resembles the ophidioceratid genus Ophioceras...
- †Xenoceras
- †Xenocheilus
- †Xiaoshaoceras
Y
- †Yakutionautilus
Yakutionautilus is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
Z
- †Zeehanoceras
- †Zerashanoceras
- †Zhuibianoceras
- †Zhuralevia
- †Zittelloceras
Zittelloceras is an extinct nauiloid genus from the order Oncocerida which are among a large group of once diverse and numerous shelled cephalopods, now represented by only a handful of species....
- †Zooceras
Zooceras is an extinct genus of prehistoric nautiloid. The nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species.-References:...
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