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Barrandeocerina
The Barrandeocerina comprise a suborder of Early Paleozoic nautiloid cephalopods, primitively coiled but later forms may be cyrtoconic, gyroconic, torticonic, and even breviconic, all having empty siphuncles with thin connecting rings. The Barrandeocerina were originally defined as a separate order by Rousseau Flower (Flower and Kummel, 1950), but since then have been united within the Tarphycerida as a suborder (Teichert 1988). Derivation is from the Tarphyceratidae. In early forms the siphuncle is central or subcentral, orthochoanitic (septal necks short and straight), and thin, with tubular segments. Later forms include those with cyrtochoanitic septal necks (curved outward) and segments that may be slightly to strongly expanded into the chambers. Taxonomy Six families are included in the Barrandeocerina, (ex Barrandeocerida). : Barrandeoceratidae M Ord-M Dev :Plectoceratidae M-U Ord :Apsidoceratidae M-U Ord : Uranoceratidae U Ord-M Sil : Lechritrochoceratidae M-U Si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apsidoceratidae
The Apsidoceratidae is a family of Middle and Upper Ordovician Barrandeocerina, (a suborder of tarphycerids), characterized by curved or coiled, smooth, transversely marked, or laterally costate shells, with a conspicuous hyponomic sinus. Early whorl sections tend to be subtriangular; become broader and dorsally impressed in closely coiled forms. Sutures are with lateral lobes in primitive forms but are without lateral lobes, but with ventral lobes in more advanced species with broader sections. Siphuncles are between the center and ventral margin, but not close to either. Genera remaining in the Apsidoceratidae include: :'' Apsidoceras'' :'' Charactoceras'' :'' Charactocerina'' :'' Deckeroceras'' :'' Fremontoceras'' :'' Wilsonoceras'' '' Chidleyenoceras'', previously assigned, tentatively, to the Apsidoceratidae has been reassigned (Flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nephriticeratidae
The Nephriticeratidae is a family of early Paleozoic (''E-M Dev'') nautilod cephalopods included in the Barrandeocerina The Barrandeocerina comprise a suborder of Early Paleozoic nautiloid cephalopods, primitively coiled but later forms may be cyrtoconic, gyroconic, torticonic, and even breviconic, all having empty siphuncles with thin connecting rings. The Bar ... (a suborder of tarphycerids ''sensu lato''), distinguished by mostly cyrtoconic as well as gyroconic, sepenticontic, and sinstrally torticonic shells with large, typically straight necked (orthchoanitic) siphuncles. As for the suborder, connecting rings are thin. Derivation The earliest genus included in the Nephriticeraatidae is the sinistrally torticconic '' Sphyradoceras'', which comes from the Lower Devonian Schoharie Formation of New York. It is in fact the only torticonic genus in the family and the only genus known from the Barrandeocerina from the Lower Devonian. The early stage of ''Sphyradoceras'' is ... [...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] |
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] |
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] |
Mollusc Suborders
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The gastropods (s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Nautiloids
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lituitidae
The Lituitidae are a family of evolved Tarphycerida, tarphycerids characterized by a long orthoconic section that follows a coiled juvenile portion at the apex, along with a generally tubular siphuncle, which like that of the Tarphycerida, barrandeocerids is composed of thin connecting rings. Taxonomic position Flower and Kummel (1950) included the Lituitidae in the Barranderocerida which are now included in the Tarphycerida as a number of derived families. Furnish and Glenister (1964)Furnish & Glenister, 1964, Nautiloidea -Tarphycerida. Treatise on Invertebrate Paleontology Part K removed the Lituitidae to the Tarphycerida on the basis of observed similarities in the structure of the siphuncle. Other taxonomies, e.g. Dzik (1981) include the Lituitidae in the Orthocerida partly on the basis of the subcentral siphuncle and thin connecting rings, on the misconception that ''Rhynchorthoceras'' is ancestral. Classification The Lituitidae comprise two basic groups, based on general f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lechritrochoceratidae
Lechritrochoceratidae is a family of derived tarphycerids from the middle and upper Silurian, once included in the now largely abandoned Barrandeocerida. Description Lechritrochoceratidae comprise dextrally torticonic genera with costate shells and ventrally displaced siphuncles. Offset coiling in low spired. Rate of expansion and coarseness of costae vary, genus to genus. Costae are generally narrow and sharp with wide areas between and slant dorso-ventrally toward the apex. Genera Six genera have been described: References * Sweet, Walter C. 1964. Nautiloidea -Barrandeocerida. Treatise on Invertebrate Paleontology, Part K. Geological Soc. of America and Univ of Kansas press. Lechritrochoceratidae -Paleodb {{Taxonbar, from=Q6511659 Nautiloids Prehistoric nautiloid families Silurian first appearances Silurian extinctions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranoceratidae
The Uranoceratidae is a family of Silurian barrandeoceroids that tend to become uncoiled with age and in which siphuncle segments tend to be expanded into the camerae.Flower, R.H. & Kummel, B. 1950. A Classification of the Nautiloidea. Journal of Paleontology vol 24, no.5, pp604–616, Sept 1950. Description Shells of uranoceratids are gyroconic. Early stages of a few species are annulated. Later stages of all are smooth or faintly striated or cancellated.Sweet, Walter C, 1964. Nautiloidea - Barrandeocerida, in Treatise on Invertebrate Paleontology, Part K, Geol Soc of America, Teichert & Moore(eds). In many, septal In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ... necks are straight, but in others recumbent on one side or the other. Connecting rings are thin. Derivation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barrandeoceratidae
The Barrandeoceratidae is a family of coiled nautiloids included in the Tarphycerida (''sensu lato'') that lived from the Middle Ordovician to the Middle Devonian, characterised by mostly compressed shells with a subcentral siphuncle composed of thin-walled segments that may become secondarily ventral.(Flower and Kummel 1950, Sweet 1964). The Barrandeoceratidae are derived from the tarphyceratid genus, ''Centrotarphyceras'' through '' Barrandeoceras'' (Flower 1984), and is the source for the Uranoceratidae and Nephriticeratidae. These three families form the barrandeoceratid group. Sometimes a fourth family, the Bickmoritidae, is added, based on the genus ''Bickmorites''. Genera (Flower 1984) include '' Barrandeoceras'', '' Centrocyrtoceras'', '' Paquettoceras'', '' Savageoceras'', '' Gasconsoceras'', ''Haydenoceras'', and '' Paraplectoceras''; and if included, '' Bickmorites''. ''Avilionella'' and ''Laureloceras'', included in the Barrandeocerida in the ''Treatise on Invert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
