| Wardoceras Temporal range: L Ordovician (Cassinian) | |
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| Genus: | Wardoceras Hook and Flower, 1977 |
Wardoceras is an extinct nautiloid genus from the late Early Ordovician of Western Utah, assigned to the orthocerid family, Michelinoceratidae
Shells of Wardoceras are smooth and orthoconic, with a circular cross section and small subcentral siphuncle, the segments of which are ventrally straight and dorsally slightly expanded into the camerae. The siphuncle is completely encircled internally by a thin lining that thickens and thins rhythmically so as to slightly thicken just forward of the septal necks, suggesting an origin in annular deposits. Cameral deposits are well developed and are thick, almost filling the ventral portion of the more apical chambers but also found in dorsal chambers as well.
Wardoceras is represented by the type species, Wardoceras orygoforme which is known only from the holotype, a 97mm long portion of a phragmocone 13.5mm in diameter at the anterior end; found 25.9 m (85 ft) above the base of the Wahwah Limestone, section J, Ibex area, Utah.
Wardoceras is named for Jane Shaw Ward, author of the Tajar stories.[ citation needed ] See also Tajaroceras , Rangeroceras , and Veneficoceras
Paraloxoceras is a genus of straight shelled, orthoconic nautiloid cephalopods, 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.
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.
Tienocerasis an orthoceratoid genus from the Permian of China (Hunan). Orthoceratoids are slender conical or near cylindrical, orthoconic, nautiloid cephalopods from the Paleozoic. Nautiloids, which include a number of different extinct orders, were far more diverse and numerous in the past, but are represented today by only two closely related genera.
Homaloceras is an extinct nautiloid cephalopod from the Middle Devonian with a strongly curved shell, included in the nautilid family Centroceratidae.
Pseudactinoceras is an extinct nautiloid cephalopod included in the order Pseudorthocerida and the namesake of the family Pseudactinoceratidae.
Osbornoceras is a genus of Lower Silurian cyrtoconic nautiloid cephalopods known from Ohio and possibly Manitoba, one of five general currently included in the oncocerid family Karoceratidae.
Jovellania is a genus of extinct prehistoric nautiloids from the order Oncocerida known from the Lower Devonian of Europe. Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.
Endolobus is an extinct genus from the nautiloid order, Nautilida. Nautiloids are a subclass of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species, including Nautilus. Endolubus is included in the family Koninckioceratidae which is part of the superfamily Taintocerataceae.
Brevicoceras is an extinct nautiloid genus from the order Oncocerida with wide distribution in the Middle Devonian in Eastern North America, Russia and Morocco. Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.
Ankyloceras is a genus of Early Devonian cephalopods included in the oncocerid family Karoceratidae. The type species, Ankyloceras nesnayamiense named by Zhuravleva, 1974, comes from Nova Zemlya in Russia. Other species have been found in Japan, Morocco, and Russia.
Permonautilus is an extinct genus of nautilids from the Upper Permian of Russia, named and described by Kruglov in 1933. Permonautilus is an involute, globular, spinose member of the Lirocertidae which are included in the Clydonautilaceae. Whorl sections are broad, with a rounded venter. The umbilicus in the middle of the shell is deep, from which spine-like processes extend laterally in the mature portion near the aperture. The siphuncle in Permonautilus is subcentral, the suture, slightly sinuous.
Neocycloceras is an extinct genus of nautiloid 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 saddles and lateral lobes and become more oblique with age. Saddles point forward, lobes to the rear. Dorsal saddles are broad and low but the ventral ones are high and conspicuous. The siphuncle is located between the center and venter and is nummuloidal, composed of rounded expanded segments, the inside of which contains a continuous laminar lining that is thickest in the middle of the segments and thinnest at the septal necks. Neocycloceras has been found in Pennsylvania in North America and in Morocco in north Africa.
Winnipegoceras is an extinct nautiloid genus from the Ordovician belonging to the Order Discosorida.
Ulrichoceras is recognised as the basal cyrtogomphoceratid genus, which is the source for the rest of the Cyrtogomphoceratidae as well as for the Westonoceratidae. The Cyrtogomphoceratidae are endogastric, the Westonoceratidae, exogastric.
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. It is the type genus for the Westonoceratidae
Valhallites is an extinct genus in the nautiloid order Nautilida which includes the living Nautilus found in the tropical western Pacifiic. Valhalites belongs to the Koninckioceratidae, a family in the Tainoceratacea, a nautilid superfamily.
Baltoceratidae is an extinct family of orthoconic cephalopods belonging to the subclass Nautiloidea endemic to what would be Asia, Australia, Europe, North America, and South America during the Ordovician living from about 480–460 mya, existing for approximately 20 million years.
Geisonocerina is an extinct genus from the carnivorous nautiloid cephalopod 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 159 million years.
Macroloxoceras is a large pseuorthocerid from the upper Devonian of Central Colorado and Southern New Mexico with features resembling those found in actinocerids. Pseudorthocerids and actinocerids are extinct nautiloid cephalopods, generally with long straight shells and expanded siphuncle segments filled with organic deposits.
Rangeroceras is an extinct orthoceratoid cephalopod genus that lived in what is now western North America during the latter part of the Early Ordovician.
