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Perkinsoceras
''Perkinsoceras''is an endocerid genus from the Middle Ordovician (Chazyan) of Champlain Valley established by Flower in 1976, which he added to his Allotrioceratidae based on certain similarities to ''Williamsoceras'' and '' Cacheoceras'' which had been added previously. ''Perkinsoceras'' is characterized by a large ventral siphuncle in broad contact with the ventral margin of the phragmocone -the chambered portion of the shell- which is expanded into a '' Nanno'' type apex, and by a broad longitudinal ventral process about which the endocones are draped. ''Perkinsoceras'' has what have been interpreted as tubules that form where the endocones impinge on the process, a feature also interpreted in ''Williamsoceras'', ''Cacheoceras'' and the distinctly unique ''Allotrioceras ''Allotrioceras'' is a tubular fossil from the Middle Ordovician of the state of New York, collected by Rousseau H. Flower; included by him in the Endocerida and placed in a new family, the Allotriocerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allotrioceratidae
The Allotrioceratidae is a family of Middle Ordovician fossils, established by Rousseau Flower, 1955, originally including ''Allotrioceras'' and '' Mirabilocras'', assigned inferentially to the Endocerida and known only from structures interpreted as siphuncles. Later ''Williamsoceras'', '' Cacheoceras'', and '' Perkinsoceras'' (Flower 1968, 1976) were added. Similar ''Allotrioceras'' and ''Mirabiloceras'', known only from the Chazyan (upper lower Middle Ordovician) of New York, are tubular organisms with complex interiors somewhat resembling that of the Endocerida. The later added ''Williamsoceras'', ''Cacheoceras'', and ''Perkinsoceras'' are true endocerids as indicated by their cylindroid shells, phragmocones, and siphuncles. ''Williamsoceras'' and ''Cacheoceras'' are from the Whiterockian stage (lower lower Middle Ordovian) of Utah. ''Perkinsoceras'', which appeared somewhat later, is from the Chazyan of New York, like ''Allotrioceras'' and ''Mirabilioceras'' but rather di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chazyoceras
''Chazyoceras'' ("Horn of the Chazyan") is a moderately large endocerid included in the Endoceratidae with a ''Nanno'' type apex and a ventral siphuncle with a holochoanitic (where "holo" is entire, and "choan" refers to its funnel-shaped opening) wall, characteristic of the family. The siphuncle swelling at the apex is subtriangular in longitudinal profile. The endocones are of medium length. ''Chazyoceras'' was named by Rousseau Flower in 1958. The genotype is ''Chazyoceras valcourense'' which came from the Middle Chazyan (Lower Middle Ordovician) of Valcour Island on Lake Champlain. ''Chazyoceras'' resembles ''Perkinsoceras'' which Flower included in the Allotrioceratidae - a family which Flower named and included in the Endocerida based on the strange fossil, ''Allotrioceras ''Allotrioceras'' is a tubular fossil from the Middle Ordovician of the state of New York, collected by Rousseau H. Flower; included by him in the Endocerida and placed in a new family, the Allo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Williamsoceras
Williamsoceras is an endocerid that Rousseau Flower (1968) added to his Allotrioceratidae (Flower 1955) on the basis of having a vertical partition within the siphuncle, known as a ventral process, with inter-connecting tubule-like structures along its margin where intercepted by endocones. Three species are named and described (Flower 1968) from the Garden City limestone of Whiterockian age near Logan and northern Utah, including the genotype ''Williamsoceras adnatum''. Two other species come from the Juab limestone (Flower 1976) of near equivalent age in the southern Confusion Range in the Ibex area in western Utah. Description Of the five described species the siphuncle wall and phragmocone are known only from the genotype ''Williamsoceras adnatum''. The other four are known only from pieces of siphuncle which show only internal configurations, but closely resemble that of the genotype. ''Williamsoceras'' is characterized by a ventral process within the siphuncle th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic 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 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 beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed 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 Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animalia
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes, containing animals such as nematodes, arthropods, flatworms, annelids and molluscs, and the deuterostomes, containing the echinoderms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
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 taxon, 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 biology, marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater mollusc, freshwater and Terrestrial molluscs, 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 Taxonomy (biology), taxonomic class (biology), classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurobiology, neurologically advanced of all inve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopoda
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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautiloidea
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 re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocerida
Endocerida is an extinct nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in their siphuncle. Endocerida was a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silurian. Their shells were variable in form. Some were straight (orthoconic), others curved (cyrtoconic); some were long (longiconic), others short (breviconic). Some long-shelled forms like '' Endoceras'' attained shell lengths close to . The related ''Cameroceras'' is anecdotally reported to have reached lengths approaching , but these claims are problematic. The overwhelming majority of endocerids and nautiloids in general are much smaller, usually less than a meter long when fully grown. Morphology Endocerids had a relatively small body chamber as well as a proportionally large siphuncle, which in some genera reached nearly half the shell diameter. This suggests that much of the visceral mass may have been housed within the siphuncle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Champlain Valley
The Champlain Valley is a region of the United States around Lake Champlain in Vermont and New York extending north slightly into Quebec, Canada. It is part of the St. Lawrence River drainage basin, drained northward by the Richelieu River into the St. Lawrence at Sorel-Tracy, Quebec (northeast of Montreal). The Richelieu valley is not generally referred to as part of the Champlain Valley. The Champlain Lake Valley is the most heavily populated region in Vermont, broadly stretching eastward from the lake's shore to the base of the Green Mountains. The state's largest city, Burlington, is located on the lake, and the city's associated suburban communities encompass part of the central section of the valley. Beyond urbanized Chittenden County, however, the valley's landscape is primarily open pasture and row crops, making the Champlain Valley the most productive agricultural region of Vermont. The New York portion of the Champlain Valley includes the eastern portions of Clint ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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