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Wutinoceras
''Wutinoceras'' is a genus of now extinct Nautiloidea, nautiloid cephalopods of the Wutinoceratidae family. It exhibits orthoconic Actinocerida, actinocerids with ventral siphuncles composed of broadly expanded segments.Memoir 2, Studies of the Actinocerida, New Mexico Bureau of Mines and Mineral ResourcesMemoir 19, The First Great Expansion of the Actinoceroids, New Mexico Bureau of Mines and Mineral Resources Distinguishing characteristics ''Wutinoceras'', as with its family the Wutinoceratidae, has a wikt:reticulate, reticulated canal system within the siphuncle, distinguishing it from later forms with arcuate canal systems. Septal necks, components of the siphuncle that project from the back side of the septa, are cyrtochoanitic (outwardly curved) and may be recumbent. Connecting rings are thick, reflective of the ancestral form. Varieties The three varieties of ''Wutinoceras'' are based on the form of the siphuncle, and each contains a number of species. These have not been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wutinoceratidae
The Wutinoceratidae are a family of early Actinocerida, actinocerids defined by Shimazu and Obata in 1938Flower 1976. New American Wutinoceratidae with Review of Actinoceroid Occurrences in Eastern Hemisphere;PartI, Memoir 28; New Mexico Bureau of Mines and Mineral Resources for actinocerids with thick connecting rings and a complex irregular canal system. Actinocerids are generally straight shelled Nautiloidea, nautiloid cephalopods with a siphuncle composed of expanded segments, typically with thin connecting rings, in which the internal deposits are penetrated by a system of canals.Teichert 1964. Actinoceratoidea, Treatise on Invertebrate Paleontology, part K.(Nautiloidea) The Wutinoceratidae include three Genus, genera,Flower 1957. Studies of the Actinoceratida. Memoir 2; New Mexico Bureau of Mines and Mineral Resources, Socorro, NM ''Wutinoceras'', ''Cyrtonybyoceras'', and ''Adamsoceras'', known especially from the early Middle Ordovician (Whiterock Stage, Whiterock stage) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinocerida
The Actinocerida are an order of generally straight, medium to large cephalopods that lived during the early and middle Paleozoic, distinguished by a siphuncle composed of expanded segments that extend into the adjacent chambers, in which deposits formed within contain a system of radial canals and a narrow space along the inner side of the connecting ring known as a paraspatium. (Teichert 1964) Septal necks are generally short and cyrtochoanitic, some being recumbent, some hook shaped. Most grew to lengths of about but some, like the Huroniidae of the Silurian grew significantly larger. Ecology The Actinocerida inhabited shallow to quite deep waters, where they alternated between swimming and lying on the bottom. They were predatory, and able to control their buoyancy to a greater degree than their contemporaries. Derivation The derivation of the Actinocerida remains enigmatic. They first appear late in the Early Ordovician (Cassinian Stage, late Floian) with the Georgin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adamsoceras
''Adamsoceras'' is a genus of actinocerids of the family Wutinoceratidae, with spheroidal siphuncle segments like '' Ormoceras'', but having a reticular canal system like ''Wutinoceras''. Adamsoceras has a slender, gently expanding, orthoconic shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ... that is slightly broader than high, i.e. depressed, with close spaced septa that form ventral lobes and a siphuncle that is near the ventral margin. ''Adamsoceras'' is known from rocks of Whiterockian age (early Middle Ordovician) in Nevada, the Baltic, Tasmania, and Manchuria. It may have been derived from ''Wutinoceras'', or from a common ancestor, and gave rise to ''Ormoceras''. The genotype is ''Adamsoceras isabelae'' from the upper Pogonip Group in Ikes Canyon in the Toquima R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armenoceratidae
The Armenoceratidae are a family of early Paleozoic nautiloid cephalopods belonging to the order Actinocerida.Flower 1957.Studies of the Actinoceratida.; Memoir 2; New Mexico Bureau of Mines and Mineral Resources, Socorro, NM Teichert 1964. Actinoceratoidea, Treatise on Invertebrate Paleontology, part K.(Nautiloidea) The Armenoceratidae, established by Troedsson (1926) are characterized by large, straight, or slightly curved shells and large siphuncles with strongly expanded segments between the septa. Septal necks are short and abruptly recurved along brims. Radial canals in the endosiphuncular canal system are typically arched, curving forward and backward from near the septal foramina (openings) to connect with the parispatium on either side of the middle of each segments. The parispatium is the narrow opening between the inner side of the connecting rings in actinocerids and the internal siphuncular deposits that grow forward and back from the region of the septal ... [...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, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period Megaannum, Ma (million years ago) to the start of the Silurian Period Ma. 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 per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. Phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautiloidea
Nautiloids are a group of cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and species rich, 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). No orthoconic and only a handful of 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-desce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symmetry, bilateral body symmetry, a prominent head, and a set of cephalopod arm, arms or tentacles (muscular hydrostats) modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt Cephalopod ink, 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 taxon, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by ''Nautilus (genus), Nautilus'' and ''Allonautilus''. In the Coleoidea, the molluscan shell has been internalized or is absent, where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthoconic
An orthocone is the long, cone-shaped shell belonging to several species of ancient nautiloid cephalopod—the prehistoric ancestors of today's marine cephalopod mollusks, including the cuttlefishes, nautiluses, octopuses and squids.; During the 18th and 19th centuries, all such shells discovered were given the "catch-all" name ''Orthoceras'', thus creating a wastebasket taxon. However, it is now known that many species, genera and families of nautiloids developed or retained this form of shell. An orthocone, loosely, may be thought of as a nautiloid shell, albeit somewhat larger and with a cone-shaped, straight formation as opposed to the nautiloid's coiled, curled shape. It was previously believed that these represented the most primitive form of nautiloid, however, it is now known that the earliest nautiloids had shells that were slightly curved. An orthoconic form evolved several times among cephalopods, and, among nautiloid cephalopods, is prevalent among the ellesmerocerids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphuncle
The siphuncle is a strand of biological tissue, tissue passing longitudinally through the mollusc shell, shell of a cephalopod mollusc. 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 Septum (cephalopod), septa (walls) dividing the Camera (cephalopod), 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 Siphon (mollusc), 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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticulate
Reticulation is a net-like pattern, arrangement, or structure. Reticulation or Reticulated may refer to: * Reticulation (single-access key), a structure of an identification tree, where there are several possible routes to a correct identification * A coloration pattern of some animals (e.g. the reticulated giraffe) * An arrangement of veins in a leaf, with the veins interconnected like a network * The endoplasmic reticulum within a cell, often resembling a net * A phylogenetic network A phylogenetic network is any graph used to visualize evolutionary relationships (either abstractly or explicitly) between nucleotide sequences, genes, chromosomes, genomes, or species. They are employed when reticulation events such as hybridi ..., the result when hybrid speciation, introgression and paraphyletic speciation is applied to a phylogenetic tree * Reticulated water (Australia, South Africa), water from a piped network rather than from a bore or well, see: wiktionary:reticulated w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manchuria
Manchuria is a historical region in northeast Asia encompassing the entirety of present-day northeast China and parts of the modern-day Russian Far East south of the Uda (Khabarovsk Krai), Uda River and the Tukuringra-Dzhagdy Ranges. The exact geographical extent varies depending on the definition: in the narrow sense, the area constituted by three Chinese provinces of Heilongjiang, Jilin, and Liaoning as well as the eastern Inner Mongolian prefectures of China, prefectures of Hulunbuir, Hinggan League, Hinggan, Tongliao, and Chifeng; in a broader sense, historical Manchuria includes those regions plus the Amur river basin, parts of which were ceded to the Russian Empire by the Manchu-led Qing dynasty during the Amur Annexation of 1858–1860. The parts of Manchuria ceded to Russia are collectively known as Outer Manchuria or Russian Manchuria, which include present-day Amur Oblast, Primorsky Krai, the Jewish Autonomous Oblast, the southern part of Khabarovsk Krai, and the easter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
