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Jiagouceras
''Jiagouceras'' is a genus of early primitive cephalopods 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. The siphuncle is close to the ventral margin, with segments expanded into the chambers. ''Jiagouceras'' is found in the Wanwankou member of the Fengshan formation (Early, Middle and Upper Trempealeauan) in northern Anhui Anhui , (; formerly romanized as Anhwei) is a landlocked province of the People's Republic of China, part of the East China region. Its provincial capital and largest city is Hefei. The province is located across the basins of the Yangtze River ..., China. It is similar to '' Paraplectronoceras'' except for having more strongly expanded siphuncular segments and less concave septa. References * Chen Jun-yuan et al., 197Late Cambrian Cephalopods of North China -- Plectronocerida, Protactinocerida (Ord Nov) and Yanhecerida (Ord Nov) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plectronoceratidae
Plectronocerida is a primitive order from which subsequent cephalopod orders are ultimately derived.Curt Teichert, 1988. Main Features of Cephalopod Evolution. The Mollusca Vol. 12 Paleontology and Neontology of Cephalopds; Academic Pres Inc. Occurrence Plectronoceratids are known from the Upper Cambrian (upper Franconian – middle Trempealeauan) of China and North America (Minnesota, Wisconsin). Two families are recognized (Flower, 1964),Flower, Rousseau H. 1964. The Nautiloid Order Ellesmeroceratida (Cephalopoda); Memoir 12, New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico the generally straight to endogastric Plectronoceratidae and the slightly exogastric Balkoceratidae. Diagnostic characters Members of the Plectronocerida are characterized as follows. Shells are generally small, some even tiny, laterally compressed, curved (cyrtochonic) or straight (orthoconic). Most cyrtoconic forms are endogastric, with the ventral side longitudinally concave, or the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trempealeauan
The Trempealeauan is the upper or latest stage of the Upper or Late Cambrian in North America, spanning about 4 million years from about 492.5 to 488.3 m.y.a., equivalent to the Fengshanian of China. The name comes from the Trempealeau Formation, named for the town of Trempealeau in western Wisconsin, located on the Mississippi River. The Trempealeauan follows, or overlies, the Franconian, which is the middle stage of the Upper Cambrian in North America and is followed by the Gasconadian in the Lower Ordovician. Together with the Dresbachian The Dresbachian is a Maentwrogian regional stage of North America, lasting from 501 to 497 million years ago. It is part of the Upper Cambrian and is defined by four trilobite zones. It overlaps with the International Commission on Stratigraphy, IC ... at the bottom, the Trempealeauan and Franconian make up the Croixan Series. References * Chen Jun-yuan & Teichert C, 1983; Cambrian Cephalopods, Geology Vol 11, pp647–650, Nov 1983 * Flowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles (muscular hydrostats) modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology. Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by ''Nautilus'' and ''Allonautilus''. In the Coleoidea, the molluscan shell has been internalized or is absent, whereas in the Nautiloidea, the external shell remains. About 800 living species of cephalopods have been ident ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Cambrian
The Furongian is the fourth and final epoch and series of the Cambrian. It lasted from to million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed 10th stage of the Cambrian. Naming The Furongian was also known as the Cambrian Series 4, and the name replaced the older term Upper Cambrian and equivalent to the local term Hunanian. The present name was ratified by the International Commission on Stratigraphy in 2003. () means 'lotus' in Mandarin and refers to Hunan which is known as the "lotus state". Definition The lower boundary is defined in the same way as the GSSP of the Paibian Stage. Both begin with the first appearance of the trilobite ''Glyptagnostus reticulatus'' around million years ago. The upper boundary is the lower boundary and GSSP of the Tremadocian Stage which is the first appearance of the conodont ''Iapetognathus fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and borders fourteen countries by land, the most of any country in the world, tied with Russia. Covering an area of approximately , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two Special Administrative Regions (Hong Kong and Macau). The national capital is Beijing, and the most populous city and financial center is Shanghai. Modern Chinese trace their origins to a cradle of civilization in the fertile basin of the Yellow River in the North China Plain. The semi-legendary Xia dynasty in the 21st century BCE and the well-attested Shang and Zhou dynasties developed a bureaucratic political system to serve hereditary monarchies, or dyna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endogastric
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Siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ''Spirula''. In the case of the cuttlefish, the siphuncle is indistinct and connects all the small chambers of that animal's highly modified shell; in the other cephalopods it is thread-like and passes through small openings in the septa (walls) dividing the camerae (chambers). Some older studies have used the term siphon for the siphuncle, though this naming convention is uncommon in modern studies to prevent confusion with a mollusc organ of the same name. Function The siphuncle is used primarily in emptying water from new chambers as the shell grows. To perform this task, the cephalopod increases the saltiness of the blood in the siphuncle, and the water moves from the more dilute chamber into the blood through osmosis. At the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fengshan Formation
Fengshan may refer to: *Feng Shan, Chinese religious ritual Geographic names People's Republic of China *Fengshan County, Guangxi () ;Subdistricts () *Fengshan Subdistrict, Shanwei, in Cheng District, Shanwei, Guangdong *Fengshan Subdistrict, Fengcheng, Liaoning * Fengshan Subdistrict, Lüliang, in Lishi District, Lüliang, Shanxi * Fengshan Subdistrict, Yuyao, Zhejiang ;Towns Written as "": * Fengshan, Hua'an County, Fujian * Fengshan, Xiaochang County, Hubei Written as "": * Fengshan, Luoyuan County, Fujian * Fengshan, Bobai County, Guangxi * Fengshan, Liucheng County, Guangxi * Fengshan, Guizhou, in Fuquan * Fengshan, Fengning County, Hebei * Fengshan, Shijiazhuang, in Jingxing Mining District, Shijiazhuang, Hebei * Fengshan, Tonghe County, Heilongjiang * Fengshan, Luotian County, Hubei *Fengshan, Jinggu County, Jinggu Dai and Yi Autonomous County, Yunnan * Fengshan, Fengqing County, Fengqing County, Yunnan ;Townships Written as "": *Fengshan Township, Heilongjiang, in H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anhui
Anhui , (; formerly romanized as Anhwei) is a landlocked province of the People's Republic of China, part of the East China region. Its provincial capital and largest city is Hefei. The province is located across the basins of the Yangtze River and the Huai River, bordering Jiangsu to the east, Zhejiang to the southeast, Jiangxi to the south, Hubei to the southwest, Henan to the northwest, and Shandong for a short section in the north. With a population of 63.65 million, Anhui is the 8th most populous province in China. It is the 22nd largest Chinese province based on area, and the 12th most densely-populated region of all 34 Chinese provincial regions. Anhui's population is mostly composed of Han Chinese. Languages spoken within the province include Jianghuai Mandarin, Wu, Hui, Gan and small portion of Zhongyuan Mandarin Chinese. The name "Anhui" derives from the names of two cities: Anqing and Huizhou (now Huangshan City). The abbreviation for Anhui is "" after the histori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraplectronoceras
''Paraplectronoceras'' is a genus of very early nautiloids 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 ''Paraplectronoceras'' is laterally compressed with the dorsal side somewhat more narrowly rounded than the ventral, and is moderately to rapidly expanded. The siphuncle is small, ventral in position, without calcareous deposits. Segments are slightly expanded, pearshaped in early stage. Septal necks are short, curved in early stage, but straight in the adult. Species of ''Paraplectronoceras'' along with another plectronoceratid, ''Lunanoceras longatum'', and the protacinocerid ''Wanwanoveras exigum'' have been found in Liaoning and Shandong provinces, in the lower part of the ''Changia Zone'', which is correlated with the earliest Trempealeauan of North America. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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