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Bisonocerida
Bisonocerida is an order of Ordovician to Silurian nautiloid Cephalopod, cephalopods. Members of this order were originally placed in the order Endocerida, but later investigation argued that this broad usage of Endocerida was a Polyphyly, polyphyletic assemblage encompassing two different groups of independent origin. Bisonocerida was differentiated from Endocerida in 2012 in order to resolve this issue. Bisonocerids are similar to endocerids in many respects. The siphuncle was broad and positioned ventrally in the shell, which ranged in shape from cyrtoconic brevicones (curved and short) to rare orthoconic longicones (straight and long). The inner surface of the siphuncle contains endosiphuncular deposits, which help distinguish the two orders. In both bisonocerids and endocerids, the endosiphuncular deposits are conical in shape ("endocones"), concreted from the rim of the siphuncle and tapering towards the apex of the shell. Both orders possess simple perforate endocones, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocerida
Endocerida, from Ancient Greek ἔνδον (''éndon''), meaning "inside", and κέρας (''kéras''), meaning "horn", 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiceratoidea
Multiceratoidea is a major subclass or superorder of Paleozoic nautiloid cephalopods. Members of this group can be characterized by nautilosiphonate connecting rings, with an organic inner layer and outer layer of calcitic spherules and blades, similar to the modern nautilus. The earliest-diverging multiceratoids have oncomyarian muscle scars (with numerous small muscle attachments ringing the body chamber), though several orders trend towards a ventromyarian condition (with muscle scar area concentrated at the bottom of the body chamber). Multiceratoid shells are generally short and curled, with a relatively small aperture (opening). Cameral deposits are never found among the multiceratoids, though several orders are known to bear endosiphuncular deposits within their siphuncles. When originally defined in 2013, Multiceratoidea included four nautiloid orders: Ellesmerocerida, Oncocerida, Discosorida, and Ascocerida. The order Tarphycerida was considered a potential member o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautiloid
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] |
Phylogenetic Analysis
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are a phylogenetic tree—a diagram depicting the hypothetical relationships among the organisms, reflecting their inferred evolutionary history. The tips of a phylogenetic tree represent the observed entities, which can be living taxa or fossils. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the taxa represented on the tree. An unrooted tree diagram (a network) makes no assumption about directionality of character state transformation, and does not show the origin or "root" of the taxa in question. In addition to their use for inferring phylogenetic patterns a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swiss Journal Of Palaeontology
The ''Swiss Journal of Palaeontology'' is a biannual open access peer-reviewed scientific journal covering palaeontology and taxonomy published by BioMed Central. It is affiliated with the Swiss Geological Society and a member of the Swiss Academy of Sciences. History The journal was established as ''Schweizerische Paläontologische Abhandlungen'' in 1874 and was published by the Natural History Museum of Basel. In 2011, it was relaunched as the ''Swiss Journal of Palaeontology'' and publisher became BioMed Central. Since 2020 the journal is open access. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2023 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 3.0. References Exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Chamber
The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the body whorl, or last whorl, is the most recently formed and largest whorl (or revolution) of a spiral or helical shell, terminating in the aperture. It is called the "body whorl" because most of the body of the soft parts of the animal fits into this whorl. The proportional size of the body whorl in gastropod shells differs greatly according to the actual shell morphology. For shells in which the rate of whorl expansion of each revolution around the axis is very high, the aperture and the body whorl are large, and the shell tends to be low spired. The shell of the abalone is a good example of this kind of shell. The opposite tendency can sometimes create a high spire with very little whorl increase per revolution. In these instances, e.g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conchiolin
Conchiolins (sometimes referred to as conchins) are complex proteins which are secreted by a mollusc's outer epithelium (the mantle). These proteins are part of a matrix of organic macromolecules, mainly proteins and polysaccharides, that assembled together form the microenvironment where crystals nucleate and grow. This organic matrix also holds and binds to the crystals of aragonite which give such shells their stiffness. The ions necessary to form calcium carbonate are also secreted by the mantle, but it is the tailored environment created by the organic matrix which causes aragonite (rather than calcite) crystals to nucleate, in much the same way that collagen nucleates hydroxyapatite crystals. Conchiolin serves as a relatively flexible, crack-deflecting matrix for the mineral aggregate particles; its strength and the strong bonding of perlucin can in some cases (such as in the formation of nacre) give the finished material an impressive level of toughness. As well ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcareous
Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcareous'' is used as an adjectival term applied to anatomical structures which are made primarily of calcium carbonate, in animals such as gastropods, i.e., snails, specifically in relation to such structures as the operculum (gastropod), operculum, the clausilium, and the love dart. The term also applies to the calcium carbonate Test (biology), tests of, often, more-or-less microscopic Foraminifera. Not all tests are calcareous; diatoms and radiolaria have siliceous tests. The molluscs are calcareous organisms, as are the Calcarea, calcareous sponges (Calcarea), that have spicules which are made of calcium carbonate. Additionally, reef-building corals, or Scleractinia, are calcareous organisms that form their rigid skeletal structure th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellesmerocerida
The Ellesmerocerida is an extinct order of primitive cephalopods belonging to the subclass Nautiloidea with a widespread distribution that lived during the Late Cambrian and Ordovician. Morphology The Ellesmerocerida are characterized by shells that are typically small, some even tiny, with close-spaced septa and relatively large ventral siphuncles. In some genera (e.g. '' Paleoceras''), the septa are uniformly spaced. Shells of ellesmerocerids are typically smooth and compressed and vary in form. They may be breviconic (short) or longiconic (elongate), straight (orthoconic) or curved (cyrtoconic). Cyrtoconic forms are usually endogastric, with longitudinally convex ventral margins. The apeces of straight forms typically have an endogastric curvature. Some may have grown to as much as 15 cm. Siphuncle segments are tubular or concave. Septal necks are short. Connecting rings which may appear layered are thick and typically wedge shaped with their maximum width at or near ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yanhecerida
Yanhecerida is a small order of Late Cambrian (mid- Stage 10) nautiloid cephalopods. They were similar to the more diverse Plectronocerida and Ellesmerocerida, with short shells, closely spaced septa, and diaphragms (partitions) within the siphuncle. Their most distinctive trait is the conical shape of the diaphragms, similar to the endocones which characterize the later nautiloid order Endocerida. While some authors have argued that Yanhecerida should be lumped into Ellesmerocerida, a phylogenetic analysis has maintained that Yanhecerida is a valid clade of early cephalopods closely related to a paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ... Ellesmerocerida (and by extension all post-Cambian cephalopods). References {{Taxonbar, from=Q35135222 Prehistoric na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tissue (biology)
In biology, tissue is an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function. Tissues occupy a Biological organisation#Levels, biological organizational level between cell (biology), cells and a complete organ (biology), organ. Accordingly, organs are formed by the functional grouping together of multiple tissues. The English word "tissue" Morphological derivation, derives from the French word "", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology. Xavier Bichat is considered as the "Father of Histology". Plant histology is Studied Space Shuttle designs, studied in both plant anatomy and Plant physiology, physiology. The classical tools for studying tissues are the Microtome#Applications, paraffin block in which tissue is embedded and then sectioned, the staining, histological stain, and the Microscope, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
