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Trimeroceras
''Trimeroceras'' is a genus of straight oncocerid (Nautilodea, Cephalopoda) from the Silurian ( Telychian to Ludlow) of Europe, China, and North America. Originally classified as a part of '' Gomphoceras'', it is now type for the Trimeroceratidae. It comprises at least five species. ''Trimeroceras bulbosum'' and ''T. cylindricum'' are found across Eurasia, while ''T. ellipticum'' is restricted to Scotland and Wales, and ''T. gilberti'' is only known from two specimens from Indiana. Fossils of the former two have been found in Sichuan, China, as well as in Gotland Gotland (, ; ''Gutland'' in Gutnish), also historically spelled Gottland or Gothland (), is Sweden's largest island. It is also a province, county, municipality, and diocese. The province includes the islands of Fårö and Gotska Sandön to the ..., Sweden and in several localities across the Czech Republic. Another related species, ''Gomphoceras alphaeus'', has been suggested to also belong to ''Trimeroceras''. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gomphoceras
''Gomphoceras'' is a questionable nautiloid cephalopod genus assigned to the Oncocerida. The family to which it might belong is undetermined. ''Gomphoceras'', named by Sowerby in 1839, is generally short but rapidly expanding, straight to slightly endogastric, with a gibbous body chamber such that all sides are convex. The aperture as vertically transverse, with a hyponomic sinus on a low spout-like process and a larger rounded dorsal sinus connetected above. ''Tetrameroceras'' and ''Trimeroceras ''Trimeroceras'' is a genus of straight oncocerid (Nautilodea, Cephalopoda) from the Silurian ( Telychian to Ludlow) of Europe, China, and North America. Originally classified as a part of '' Gomphoceras'', it is now type for the Trimeroceratid ...'', both oncocerids, are similar in general form, but have more complex apertures. References * Oncocerida Paleozoic cephalopods of Europe Paleozoic life of Manitoba Bertie Formation Silurian cephalopods {{paleo-cephalopod-st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimeroceratidae
Trimeroceratidae is a family of molluscs in the order Oncocerida. These molluscs were fast-moving nektobenthic carnivores. They lived in the Silurian period. Distribution Species have been found in Silurian-era strata of Canada (Québec), China, Czechia, Italy, Russia, Sweden, and the United States (Indiana, Wisconsin). Genus * '' Clathroceras'' * '' Eotrimeroceras'' * ''Inversoceras'' * '' Jeppssonoceras'' * '' Patagiumoceras'' * '' Pentameroceras'' * '' Plemeroceras'' * '' Simonssoceras'' * '' Stenogomphoceras'' * '' Trimeroceras'' See also *List of nautiloids This list of nautiloids is a comprehensive listing of all genera that have ever been included in the subclass Nautiloidea, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered in ... ReferencesPaleobiology Database Oncocerida Prehistoric cephalopod families Silurian first appearances Silurian extinctions {{silurian-animal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oncocerid
The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous; one possible member is known from the Early Permian), in which the connecting rings are thin and siphuncle segments are variably expanded (Flower, 1950). 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 (Sweet, 1964). Physical characteristics The shells of oncocerids are primarily somewhat compressed cyrtoconic brevicones. More advanced forms include gyrocones, serpenticones, torticones, and elongate orthocones and cyrtocones, reflective of the different families and genera (Flower, 1950; Sweet, 1964). The siphuncle in the Oncocerida is commonly located at or near the ventral margin. Connecting rings are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telychian
In the geologic timescale, the Telychian is the geologic age, age of the Llandovery Epoch of the Silurian geologic period, Period of the Paleozoic geologic era, Era of the Phanerozoic geologic eon, Eon. The Telychian Age was between 438.5 ± 1.2 million years ago (Ma) and 433.4 ± 0.8 Ma. The Telychian Age succeeds the Aeronian Age and precedes the Sheinwoodian Age. The name of the interval is derived from the Pen-lan-Telych Farm near Llandovery, Powys, Wales. The GSSP is located within the Wormwood Formation. It ended with the Ireviken event. Ireviken event The Ireviken event was the first of three relatively minor extinction events (the Ireviken, Mulde event, Mulde, and Lau event, Lau events) during the Silurian Period. It occurred at the Llandovery epoch, Llandovery/Wenlock epoch, Wenlock boundary (mid Silurian, ). The event is best recorded at Ireviken, Gotland, where over 50% of trilobite species became extinct; 80% of the global conodont species also become extinct in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludlow
Ludlow () is a market town in Shropshire, England. The town is significant in the history of the Welsh Marches and in relation to Wales. It is located south of Shrewsbury and north of Hereford, on the A49 road which bypasses the town. The town is near the confluence of the rivers Corve and Teme. The oldest part is the medieval walled town, founded in the late 11th century after the Norman conquest of England. It is centred on a small hill which lies on the eastern bank of a bend of the River Teme. Situated on this hill are Ludlow Castle and the parish church, St Laurence's, the largest in the county. From there the streets slope downward to the rivers Corve and Teme, to the north and south respectively. The town is in a sheltered spot beneath Mortimer Forest and the Clee Hills, which are clearly visible from the town. Ludlow has nearly 500 listed buildings, including examples of medieval and Tudor-style half-timbered buildings. The town was described by Sir John Betjeman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indiana
Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th state on December 11, 1816. It is bordered by Lake Michigan to the northwest, Michigan to the north, Ohio to the east, the Ohio River and Kentucky to the south and southeast, and the Wabash River and Illinois to the west. Various indigenous peoples inhabited what would become Indiana for thousands of years, some of whom the U.S. government expelled between 1800 and 1836. Indiana received its name because the state was largely possessed by native tribes even after it was granted statehood. Since then, settlement patterns in Indiana have reflected regional cultural segmentation present in the Eastern United States; the state's northernmost tier was settled primarily by people from New England and New York, Central Indiana by migrants fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sichuan
Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the Sichuan Basin and the easternmost part of the Tibetan Plateau between the Jinsha River on the west, the Daba Mountains in the north and the Yungui Plateau to the south. Sichuan's capital city is Chengdu. The population of Sichuan stands at 83 million. Sichuan neighbors Qinghai to the northwest, Gansu to the north, Shaanxi to the northeast, Chongqing to the east, Guizhou to the southeast, Yunnan to the south, and the Tibet Autonomous Region to the west. In antiquity, Sichuan was the home of the ancient states of Ba and Shu. Their conquest by Qin strengthened it and paved the way for Qin Shi Huang's unification of China under the Qin dynasty. During the Three Kingdoms era, Liu Bei's state of Shu was based in Sichuan. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gotland
Gotland (, ; ''Gutland'' in Gutnish), also historically spelled Gottland or Gothland (), is Sweden's largest island. It is also a province, county, municipality, and diocese. The province includes the islands of Fårö and Gotska Sandön to the north, as well as the Karlsö Islands ( Lilla and Stora) to the west. The population is 61,001, of which about 23,600 live in Visby, the main town. Outside Visby, there are minor settlements and a mainly rural population. The island of Gotland and the other areas of the province of Gotland make up less than one percent of Sweden's total land area. The county formed by the archipelago is the second smallest by area and is the least populated in Sweden. In spite of the small size due to its narrow width, the driving distance between the furthermost points of the populated islands is about . Gotland is a fully integrated part of Sweden with no particular autonomy, unlike several other offshore island groups in Europe. Historically there was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Czech Republic
The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The Czech Republic has a hilly landscape that covers an area of with a mostly temperate continental and oceanic climate. The capital and largest city is Prague; other major cities and urban areas include Brno, Ostrava, Plzeň and Liberec. The Duchy of Bohemia was founded in the late 9th century under Great Moravia. It was formally recognized as an Imperial State of the Holy Roman Empire in 1002 and became a kingdom in 1198. Following the Battle of Mohács in 1526, the whole Crown of Bohemia was gradually integrated into the Habsburg monarchy. The Protestant Bohemian Revolt led to the Thirty Years' War. After the Battle of White Mountain, the Habsburgs consolidated their rule. With the dissolution of the Holy Empire in 1806, the Cro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spadix (zoology)
In the field of zoology, a spadix ( ; plural spadices , ) is a secondary sexual characteristic, secondary sexual organ found in some cephalopods and hydrozoans. In the genus ''Nautilus'', the spadix is a composite erectile organ in the male located in the oral region which is composed of four highly modified tentacles and which is paired with a somewhat smaller antispadix that is also composed of four tentacles. The spadix is normally a concealed organ but quickly becomes distended upon the animal's death. The exact function of the spadix and antispadix in ''Nautilus'' is not yet known. See also *Spadix (botany) References Cephalopod zootomy Sex organs {{Animal-anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus
The nautilus (, ) is a pelagic marine mollusc of the cephalopod family Nautilidae. The nautilus is 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''. Though it more specifically refers to species ''Nautilus pompilius'', the name chambered nautilus is also used for any of the Nautilidae. All are protected under CITES Appendix II. Depending on species, adult shell diameter is between 4 and 10 inches. Nautilidae, both extant and extinct, are characterized by involute or more or less convolute shells that are generally smooth, with compressed or depressed whorl sections, straight to sinuous sutures, and a tubular, generally central siphuncle.Kümmel, B. 1964. Nautiloidae-Nautilida, in the Treatise on Invertebrate Paleontology, Geological Society of America and Univ of Kansas Press, Teichert and Moore eds. Having survived relatively u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
