Shuranoceras

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Shuranoceras
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Nautiloidea
Order:
Oncocerida
Family:
Karoceratidae
Genus:
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, slowly enlarging orthoconic shellwith a ventral submarginal siphuncle composed of complrex segments. Shuranoceras was found in middle Silurian strata in Ferghana, central Asia.

Oncocerida order of molluscs

The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian, in which the connecting rings are thin and siphuncle segments are variably expanded. At present the order consists of some 16 families, a few of which, such as the Oncoceratidae, Brevicoceratidae, and Acleistoceratidae contain a fair number of genera each while others like the Trimeroceratidae and Archiacoceratidae are represented by only two or three.

In the geological timescale, the Llandovery epoch occurred at the beginning of the Silurian period. The Llandoverian epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up of ecosystems.

The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 419.2 million years ago (Mya), to the beginning of the Carboniferous, 358.9 Mya. It is named after Devon, England, where rocks from this period were first studied.

Oncocerids (Order Oncocerida) were Nautiloid cephalopods that lived during the early part of the Paleozoic Era. They are closely related to the Nautilids that include the living Nautilus , but on a different evolutionary branch

The PaleozoicEra is the earliest of three geologic eras of the Phanerozoic Eon. It is the longest of the Phanerozoic eras, lasting from 541 to 251.902 million years ago, and is subdivided into six geologic periods : the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era.

Nautilida Order of cephalopods

The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species. All told, between 22 and 34 families and 165 to 184 genera have been recognised, making this the largest order of the subclass Nautiloidea.

Nautilus family of molluscs

The nautilus is a pelagic marine mollusc of the cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina.

See also

Related Research Articles

Jangziceras is a genus of fossil nautiloid cephalopods 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. Its description falls within the characters of the Orthocerida.

Pseudobrevicoceras is an extinct genus of nautilitoid cephalopods in the order Oncocerida. The familial position is undetermined.

Octamerella is an extinct genus of prehistoric nautiloids from the oncocerid family Hemiphragmoceratidae that lived in what is now Europe and North America during the Middle Silurian.

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.

<i>Kionoceras</i> genus of molluscs (fossil)

Kionoceras is an extinct nautiloid cephalopod genus included in the orthocerid family Kionoceratidae with scattered worldwide distribution from the Middle Ordovician to the Lower Permian. Kionoceratids are orthocerids with prominent longitudinal ornamentation on their shells, sometimes augmented by secondary transverse ornamenttion. Orthocerids are, of course, prehistoric nautiloides with generally straight and elongate shells, mostly with central or subcentral siphuncles.

Antigyroceras is a genus of nautiloids in the order Discosorida, known from central Asia, that lived during Late Silurian and Early Devonian times. It is contemporary with the discosorid Endoplectoceras

Zittelloceras is an extinct genus of nauiloids 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.

Streptoceras is a genus in the extinct oncocerid family Acleistoceratidae that plied the shallow sea floor from the Middle Silurian to the Middle Devonian. Streptoceras is characterized by a shell that is large but short in proportion (breviconic) with the ventral profile convex and dorsal profile concave in the posterior part, convex over the body chamber, then concave toward the front, like Amphycertoceras, but with a triangular shaped aperture. Streptoceras is found in the Middle Silurian of North America,in Ontario.

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 25.3 million years.

<i>Inversoceras</i> genus of molluscs

Inversoceras is a genus of cephalopods in the order Oncocerida and the family Trimeroceratidae. These mollusks were fast-moving nektobenthic carnivores. They lived in the Silurian period, from the Lower Wenlock age to the Ludlow age.

Aktjubocheilus is a genus of oncocerid nautiloids from the Upper Devonian included in the Acleistoceratidae, a family characterized by depressed, or rarely compressed, exogastric brevicones and cyrtocones.

Balashovia is a genus of oncocerid nautiloids from the Middle Devonian,, included in the Archiacoceratidae, a family characterized by compressed, exogastric, cyrtocones with a large, actinosiphonate, dorsal siphuncle.

Tetrameroceras is a genus of short, essentially straight, breviconic, nautiloid cephalopods from the middle and Upper Silurian of Europe and North America included in the oncocerid family Hemiphragmoceraidae.

Wadeoceras is a genus of nautiloids included in the Polyelasmoceratidae, a family of oncocerids living from the Middle Silurian to the Late Devonian.

Karoceras is a genus of oncocerid nautiloids that lived during the Silurian and possibly Early Devonian, type genus for the Karoceratidae. The shell is a compressed, exogastric cyrtocone, section sub ovoid. The siphuncle is ventral, near the outer, externally convex curvature. Septal necks flair outwardly, segments are inflated ventrally and are straight dorsally, a character of the family.

Polyelasmoceratidae is a family of oncocerid nautiloids characterized by rapidly expanding endogastrically curved shells, curved such that the ventral side is longitudinally concave. In cross section shells are typically tear-drop in shape to subtriangular. The siphuncle is typically nummuloidal, like a string of beads, with outwardly flared septal necks, and located between the center and the venter. Most contain radially lamellar actinosiphonate deposits.

Maelonoceras is a Late Ordovician - early Silurian oncocerid found in Ontario.

<i>Lorieroceras</i>

Lorieroceras lorieri is an extinct oncocerid nautilitoidean cephalopod belonging to the family Nothoceratidae. Fossils are found in Lower Devonian marine strata of France. Its shell is unusual among nautiloids in that it is a loosely coiled, turban-shaped helix that is sinistrally coiled.

References

    The 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 extant invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, genera with no fossil record whatsoever have just a very brief listing.


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