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Campbelloceras
''Campbelloceras'' is a tarphyceratid nautiloid known from the Lower Ordovician, Upper Canadian Epoch of North America, where it is widespread. ''Campbelloceras'' was named by Ulrich and Foerste in 1936. The shell of ''Campbelloceras'' has a circular whorl section, only slightly impressed, and a siphuncle that is close to the venter in all growth stages. ''Campbelloceras'' differs from ''Tarphyceras'' in that the rate of expansion is greater, the siphuncle is proportionally largers, and an impression is shallower. ''Campbelloceras'' may have given rise to the barrandeocerid '' Plectoceras'' (Plectoceratidae) through simplification of the connecting rings, and to ''Tarphyceras'' through tighter coiling, development of a deeper impression, and reduction in the size of the siphuncle. ''Campbelloceras'' may be conceivably derived from '' Estonioceras'' (Estonioceratidae). The cross section of ''Campbelloceras'' and that of the outer whorl of ''Estonioceras'' are similar, except f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarphyceratidae
The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from ''Bassleroceras'' or possibly from some member of the Estonioceratidae. Tarphyceratids vary in form and siphuncle position. The siphuncle may be subcentral as in ''Centrotarphyceras''; intermediary as in '' Tarphyceras'', or subventral as in '' Campbelloceras''. Cross sections vary. ''Tarphyceras'' and ''Campbelloceras'' are rounded. ''Centrotarphyceras'' is subquadrate with broadly rounded flanks and a slightly rounded venter. ''Eurystomites'' is subquadrate and slightly compressed, with the maximum width closer to the dorsum. ''Pionoceras'' is subrounded and slightly depressed with the maximum width closer to the venter. The dorsal impression in ''Tarphyceras'' and ''Eurystomites'' is broad and deep and in ''Pionoceras'' and ''Centrotarphyceras'', broad an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarphyceras
''Tarphyeras'' is a genus of tarphyceratid with whorls rounded in cross section, having a deeply impressed dorsum and a ventral to subcentral siphuncle, known from the Lower Ord (U Canad) of North America. It differs from '' Campbelloceras'' in that ''Campbelloceras'' is only slightly impressed, from '' Centrotarphyceras'' in that ''Centrotarphyceras'' is subquadrate and has a central siphuncle, and from ''Trocholites'' in that although ''Trocholites'' is subcircular in cross section, the siphuncle is subdorsal. ''Taphyceras'' may be derived from ''Campbelloceras'' through development of tighter coiling and a deeper impression along with a smaller 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 ... that may be further offset from the venter. ''Tarphyceras'' was named by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarphycerida
The Tarphycerida were the first of the coiled cephalopods, found in marine sediments from the Lower Ordovician (middle and upper Canad) to the Middle Devonian. Some, such as '' Aphetoceras'' and '' Estonioceras'', are loosely coiled and gyroconic; others, such as '' Campbelloceras'', '' Tarphyceras'', and '' Trocholites'', are tightly coiled, but evolute with all whorls showing. The body chamber of tarphycerids is typically long and tubular,Furnish and Glenister 1964; Nautiloidea - Tarphycerida; In the ''Treatise on Invertebrate Paleontology'' Vol K; Teichert and Moore, (eds) GSA and U of Kansas Press 1964 as much as half the length of the containing whorl in most, greater than in the Silurian Ophidioceratidae. The Tarphycerida evolved from the elongated, compressed, exogastric Bassleroceratidae, probably ''Bassleroceras'', around the end of the Gasconadian through forms like ''Aphetoceras''. Close coiling developed rather quickly, and both gyroconic and evolute forms are fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plectoceras
''Plectoceras'' is a genus of nautiloids included in the tarphycerid suborder Barrandeocerina that lived during the Middle and Late Ordovician. It has been found widespread in the Middle and Upper Ordovician of North America. ''Plectoceras'' has a coiled, costate shell with a perforate (see-through) umblilcus; whorls are dorsally impressed by end of first volution but loosen in the adult stage with the mature body chamber diverging from the adjacent whorl. Costae (ribs) slope dorso-ventrally toward the apex and sutures are straight or have lateral lobes. The siphuncle is subventral, orthochoanitic with short, straight necks and thin connecting rings. ''Plectoceras'' and its contemporary ''Barrandeoceras'' are both likely derived from the Tarphyceratidae; ''Plectoceras'' with its subventral siphuncle possibly from ''Campbelloceras ''Campbelloceras'' is a tarphyceratid nautiloid known from the Lower Ordovician, Upper Canadian Epoch of North America, where it is widespread. ''Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plectoceratidae
The Plectoceratidae is a family of tarphycerids in the suborder Barrandeocerina established as a place for the genus '' Plectoceras''; defined (Sweet 1964) simply as coiled, costate barrandeocerids with subcentral adult siphuncle. According to Sweet, in the original ''Treatise'' Part K, the Plectoceratidae included only ''Plectoceras''. Flower, 1984, however added six other genera, two new and four removed from both the Barrandeoceratidae and Apsidoceratidae. Genera according to Flower, 1984 are: '' Plectoceras'' Hyatt -type genus '' Avilionella'' -removed from Barradeoceratidae '' Bodeiceras'', Flower 1984. added '' Chidleyenoceras'' - removed from the Apsidoceratidae '' Metaplectoceras'', Flower (?synonym for Plectoceras) '' Laureloceras'' Flower 1957, removed from Barrandeoceratidae '' Laurelplecoceras'' Flower 1984 -added According to Flower, 1984, ''Plectoceras'', and therefore the Plectoceratidae, is derived from the Tarphyceratid genus '' Campbelloceras'' while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautiloid
Nautiloids are a group of marine cephalopods ( Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and speciose, with over 2,500 recorded species. They flourished during the early Paleozoic era, when they constituted the main predatory animals. Early in their evolution, nautiloids developed an extraordinary diversity of shell shapes, including coiled morphologies and giant straight-shelled forms ( orthocones). Only a handful of rare coiled species, the nautiluses, survive to the present day. In a broad sense, "nautiloid" refers to a major cephalopod subclass or collection of subclasses (Nautiloidea ''sensu lato''). Nautiloids are typically considered one of three main groups of cephalopods, along with the extinct ammonoids (ammonites) and living coleoids (such as squid, octopus, and kin). While ammonoids and coleoids are monophyletic clades with exclusive ancestor-descendant rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Celtic Britons, Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same Rock (geology), rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed Stratum, strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Union of Geological Sciences, Intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Epoch
The Canadian is the Lower or Early Ordovician in North America. The term is common in the older literature and has been well understood for more than a century. However it has no official recognition by the International Commission on Stratigraphy (ICS) and has been superseded by the more recently defined Ibexian series of western Utah. Background Dana introduced the Canadian as the name for a system separated from the rest of the Ordovician (Weller 1980), then known as the Lower Silurian, and referred to the rest of the Lower Silurian as the Trenton System. At that time the Ordovician had not yet been recognized. Later Ulrich redefined the Canadian as roughly equivalent to the Beekmantown strata of the Lower Ordovician. Flower (1957 p. 17) felt that recognition of the Canadian as a separate system would greatly solve problems in Early Paleozoic stratigraphy. As such, faunas in limestones of Canadian age are uniformly widespread and set off sharply from black shale graptolite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Estonioceras
''Estonioceras'' is an extinct genus of tarphyceridan nautiloids from the Ordovician of Europe. Sources * ''Dinosaur Encyclopedia'' by Jayne Parsons * ''Fossils'' (Smithsonian Handbooks) by David Ward External links''Estonioceras''in the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pale ... Prehistoric nautiloid genera Ordovician cephalopods of Europe Fossil taxa described in 1883 {{paleo-Nautiloidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estonioceratidae
The Estonioceratidae are a family of loosely coiled tarphycerids in which the inner side of the whorls, which forms the dorsum, is rounded or flat with no impression, and in which the siphuncle, composed of thick tubular segments, is located ventrally. The Estonioceratidae seem to form a link between the ancestral Bassleroceratidae and the more tightly coiled Tarphyceratidae The Tarphyceratidae are tightly coiled, evolute Tarphycerida with ventral siphuncles. The dorsum is characteristically impressed where the whorl presses against the venter of the previous. The Tarphyceratidae are derived from ''Bassleroceras'' or ....Furnish, W. M, and Glenister, Brian F. 1964. Nautiloidea – Tarphycerida; Treatise on Invertebrate Paleontology, Part K, Geol. Soc. of America, Teichert and Moore (eds.) References {{Taxonbar, from=Q16965822 Cephalopod families Nautiloids Ordovician cephalopods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treatise On Invertebrate Paleontology
The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') 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 (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing. Publication of the decades-long ''Treatise on Invertebrate Paleontology'' is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post-Paleozoic era caenogastropods (a molluscan group including the whelk and Common periwinkle, periwinkle). Furthermore, every so often, previously published volumes of the ''Treatise'' are revised. Evolution of the proje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
