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Grypoceras
''Grypoceras'' is a coiled nautiloid cephalopod from the Triassic of western North America, southern Asia, and Europe that belongs to the nautilid family Grypoceratidae. Named by Alpheus Hyatt Alpheus Hyatt (April 5, 1838 – January 15, 1902) was an American zoologist and palaeontologist. Biography Alpheus Hyatt II was born in Washington, D.C. to Alpheus Hyatt and Harriet Randolph (King) Hyatt. He briefly attended the Maryla ... in 1883, the shell of ''Grypoceras'' is essentially involute with a subtriangular cross section, widest across the umbilical shoulders, with flanks fairing toward a narrow flattened venter. Sutures on flanks are with smooth, deep lobes and with shallow ventral lobes. The earlier, related '' Domatoceras'' is evolute, with a more quadrate whorl section. '' Gryponautilus'', from the Upper Triassic, is more strongly involute and has a sharply keeled venter. References * Bernhard Kummel, 1964, Nautiloidea-Nautilida. Treatise on Invertebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grypoceratidae
Grypoceratidae is the longest-lived family of the Trigonoceratoidea, or of the near equivalent Centroceratina; members of the Nautilida from the Upper Paleozoic and Triassic.Kummel,B. 1964. Nautiloidea-Nautilida, Treatise on Invertebrate Paleontology Part K, Teichert and Moore (eds) Geological Society of America and University of Kansas Press. Diagnosis The Grypoceratidae are characterized by evolute to involute shells that may have some modification to the venter (the outer rim) varying from flattened to subangular, or bearing a keel. Most are smooth but some have nodes or carinae (auxiliary keels). Sutures generally have distinct ventral and lateral lobes but in some, a ventral saddle. Whorl sections are generally compressed but may be subquadrate to subtrapezoidal or coronate (heart shaped), or slightly depressed dorso-ventrally.Flower 1950;Flower and Kummel, A Classification of the Nautiloidea, Journal of Paleontology Vol 24, no.5, pp 604–616, Sept 1950. Phylogeny and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gryponautilus
''Gryponautilus'' is a genus of Upper Triassic nautilids (''generally coiled nautiloid cephalopods'') belonging to the trigonoceratacean family Grypoceratidae, characterized by involute, inflated shells, which at maturity develop narrowly rounded keel-like venters. Venters on inner whorls are truncated and broadly convex to concave. Immature forms bear a resemblance to ''Grypoceras ''Grypoceras'' is a coiled nautiloid cephalopod from the Triassic of western North America, southern Asia, and Europe that belongs to the nautilid family Grypoceratidae. Named by Alpheus Hyatt Alpheus Hyatt (April 5, 1838 – January ...''. References * Prehistoric nautiloid genera {{paleo-nautiloidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of archo ... [...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] |
Nautilida
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. Classification and phylogeny Current classification The current classification of the Nautilida, in prevalent use, is that of Bernhard Kummel (Kummel 1964) in the Treatise which divides the Nautilida into five superfamilies, the Aipocerataceae, Clydonautilaceae, Tainocerataceae, and Trigonocerataceae, mostly of the Paleozoic, and the later Nautilaceae. These include 22 families and some 165 or so genera (Teichert and Moore 1964) Other concepts Shimansky 1962 (in Kummel 1964) divided the Nautilida into five suborders, the mostly Paleozoic Centroceratina, Liroceratina, Rutoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpheus Hyatt
Alpheus Hyatt (April 5, 1838 – January 15, 1902) was an American zoologist and palaeontologist. Biography Alpheus Hyatt II was born in Washington, D.C. to Alpheus Hyatt and Harriet Randolph (King) Hyatt. He briefly attended the Maryland Military Academy and Yale University, and after graduating from Harvard University in 1862, he enlisted as a private in the Massachusetts Volunteer Infantry for the Civil War, emerging with the rank of captain. After the war he worked for a time at the Essex Institute (now the Peabody Essex Museum in Salem, Massachusetts. He and a colleague founded ''American Naturalist'' and Hyatt served as editor from 1867 to 1870. He became a professor of paleontology and zoology at Massachusetts Institute of Technology in 1870, where he taught for eighteen years, and was professor of biology and zoology at Boston University from 1877 until his death in 1902. He also served as curator of the Boston Society of Natural History, where his longtime a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domatoceras
''Domatoceras'' is a nautiloid genus and member of the Grypoceratidae from the Pennsylvanian and Permian with a wide spread distribution. The shell of ''Domatoceras'' is evolute, coiled with whorls touching but not overlapping, some growing to be moderately large. Whorl section subquadrate, higher than wide. Sides essentially straight to slightly bowed and slightly convergent on a broad slightly arched venter on the outer rim. Shoulder are narrow but rounded. Chambers are short but lengthen slightly before the mature living chamber, septa close spaced, sutures form broad shallow lateral and ventral lobes and sharp ventro-lateral saddles. The dorsum in slightly impressed (indented) where it rides over the previous whorl. The 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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