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Brachiopods
Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection. Two major categories are traditionally recognized, articulate and inarticulate brachiopods. The word "articulate" is used to describe the tooth-and-groove structures of the valve-hinge which is present in the articulate group, and absent from the inarticulate group. This is the leading diagnostic skeletal feature, by which the two main groups can be readily distinguished as fossils. Articulate brachiopods have toothed hinges and simple, vertically-oriented opening and closing muscles. Conversely, inarticulate brachiopods have weak, untoothed hinges and a more complex system of vertical and oblique (diagonal) muscles used to keep the two valves aligned. In many brachiopods, a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halkieria
The halkieriids are a group of fossil organisms from the Lower to Middle Cambrian. Their eponymous genus is ''Halkieria'' , which has been found on almost every continent in Lower to Mid Cambrian deposits, forming a large component of the small shelly fossil assemblages. The best known species is ''Halkieria evangelista'', from the North Greenland Sirius Passet Lagerstätte, in which complete specimens were collected on an expedition in 1989. The fossils were described by Simon Conway Morris and John Peel in a short paper in 1990 in the journal ''Nature''. Later a more thorough description was undertaken in 1995 in the journal ''Philosophical Transactions of the Royal Society of London'' and wider evolutionary implications were posed. The group is sometimes equated to Sachitida, although as originally envisaged, this group includes the wiwaxiids and is thus equivalent to the Halwaxiida. History of discovery Armor plates called "sclerites" had long been known as elements of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchonelliform
Rhynchonelliformea is a major subphylum and clade of brachiopods. It is equivalent to the former class Articulata, which was used previously in brachiopod taxonomy. Articulate brachiopods have many anatomical differences relative to "inarticulate" brachiopods of the subphyla Linguliformea and Craniformea. Articulates have hard calcium carbonate shells with tongue-and-groove hinge articulations (hence the name) and separate sets of simple opening and closing muscles. The name, Rhynchoelliformea, which replaces Articulata, which is also a class of crinoids, comes from the family Rhynchonellidae, which however is no more representative of articulate brachiopods than any other group such as spirifers or strophomenids. It just happens to be the name chosen, based on an included taxon. The main difference between the Rhynchonelliformea described in the Treatise Part H, revised 2000/2007, and the Articulata of the Treatise part H, 1965, lies in the groups included, their taxonomic po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchonelliformea
Rhynchonelliformea is a major subphylum and clade of brachiopods. It is equivalent to the former class Articulata, which was used previously in brachiopod taxonomy. Articulate brachiopods have many anatomical differences relative to "inarticulate" brachiopods of the subphyla Linguliformea and Craniformea. Articulates have hard calcium carbonate shells with tongue-and-groove hinge articulations (hence the name) and separate sets of simple opening and closing muscles. The name, Rhynchoelliformea, which replaces Articulata, which is also a class of crinoids, comes from the family Rhynchonellidae, which however is no more representative of articulate brachiopods than any other group such as spirifers or strophomenids. It just happens to be the name chosen, based on an included taxon. The main difference between the Rhynchonelliformea described in the Treatise Part H, revised 2000/2007, and the Articulata of the Treatise part H, 1965, lies in the groups included, their taxonomic po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linguliformea
Linguliformea is a subphylum of inarticulate brachiopods. These were the earliest of brachiopods, ranging from the Cambrian into the Holocene. They rapidly diversified during the Cambrian into the Ordovician, but most families became extinct by the end of the Devonian. The articulation in these brachiopods is lacking. These brachiopods have adductor and oblique muscles, but no diductor muscles. The anus is located at the side of the body. The pedicle is a hollow extension of the ventral body wall. Posterior body wall separates dorsal and ventral mantles. The shells are usually made up of apatite (calcium phosphate), however rare cases have calcite or aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including prec ... shells. See also * References Brachiopod taxonomy Paleozoic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linguliform
Linguliformea is a subphylum of inarticulate brachiopods. These were the earliest of brachiopods, ranging from the Cambrian into the Holocene. They rapidly diversified during the Cambrian into the Ordovician, but most families became extinct by the end of the Devonian. The articulation in these brachiopods is lacking. These brachiopods have adductor and oblique muscles, but no diductor muscles. The anus is located at the side of the body. The pedicle is a hollow extension of the ventral body wall. Posterior body wall separates dorsal and ventral mantles. The shells are usually made up of apatite (calcium phosphate), however rare cases have calcite or aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pre ... shells. See also * References Brachiopod taxonomy Paleo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Craniida
The Craniidae are a family of brachiopods, commonly known as lamp shells. Although it belongs to a subdivision called the inarticulata which have shells where the mineral content consist of calcium phosphate, the Craniidae have shells that consist of calcium carbonate. Other special characteristics of this family are that no outgrowths are developed to form a hinge between both valves, nor is there any support for the lophophore. As adults, craniids either lived free on the ocean floor or, more commonly, were attached to a hard object with all or part of the ventral valve. In craniids, a pedicle is not known from any development stage. They are the only members of the order Craniida and the monotypic suborder Craniidina and superfamily Cranioidea; consequently, the latter two taxa are presently redundant and not used very often. ''Valdiviathyris'' and ''Neoancistrocrania'' were sometimes separated in a family Valdiviathyrididae but this has turned out to be unjustified. Most Cra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedicle
Pedicle or pedicel may refer to: Human anatomy *Pedicle of vertebral arch, the segment between the transverse process and the vertebral body, and is often used as a radiographic marker and entry point in vertebroplasty and kyphoplasty procedures *Pedicle of a skin flap (medicine) *Hilum of kidney, also called the renal pedicle *Pedicel, a foot process of a renal podocyte Animal anatomy * Pedicle in brachiopods, a fleshy line used to attach and anchor brachiopods and some bivalve mollusks to a substrate *Pedicle (cervidae), the attachment point for antlers in cervids * Pedicel (antenna), the second segment of the antenna in the class Insecta, where the Johnston's organ is found * Pedicel or petiole (insect), the stem formed by a restricted abdominal segment which connects the thorax with the gaster (the remaining abdominal segments) in the suborder Apocrita * Pedicel (spider), the narrow segment connecting the cephalothorax with the abdomen Other *Pedicel (botany), the stalk of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terebratalia Transversa
''Terebratalia'' is a genus of brachiopods belonging to the family Terebrataliidae. The species of this genus are found in Northern America and Japan. Species: *'' Terebratalia asanoi'' *'' Terebratalia batequia'' *'' Terebratalia bialata'' *'' Terebratalia coreanica'' *'' Terebratalia gouldi'' *'' Terebratalia hayasakai'' *'' Terebratalia pacifica'' *'' Terebratalia radiata'' *'' Terebratalia sendaica'' *'' Terebratalia tisimana'' *''Terebratalia transversa ''Terebratalia'' is a genus of brachiopods belonging to the family Terebrataliidae. The species of this genus are found in Northern America and Japan. Species: *''Terebratalia asanoi'' *''Terebratalia batequia'' *''Terebratalia bialata'' *'' ...'' *'' Terebratalia xanthica'' *'' Terebratula tenuis'' References {{Taxonbar, from=Q3543443 Brachiopod genera Terebratulida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostome
Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's members, although the reverse is typically true of its sister clade, Deuterostomia. Well known examples of protostomes are arthropods, molluscs, annelids, flatworms and nematodes. They are also called schizocoelomates since schizocoely typically occurs in them. Together with the Deuterostomia and Xenacoelomorpha, these form the clade Bilateria, animals with bilateral symmetry, anteroposterior axis and three germ layers. Protostomy In animals at least as complex as earthworms, the first phase in gut development involves the embryo forming a dent on one side (the blastopore) which deepens to become its digestive tube (the archenteron). In the sister-clade, the deuterostomes (), the original dent becomes the anus while the gut eventually tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderm
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single limb. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chordate
A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five synapomorphies include a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, and a post-anal tail. The name “chordate” comes from the first of these synapomorphies, the notochord, which plays a significant role in chordate structure and movement. Chordates are also Bilateral symmetry, bilaterally symmetric, have a coelom, possess a circulatory system, and exhibit Metameric, metameric segmentation. In addition to the morphological characteristics used to define chordates, analysis of genome sequences has identified two conserved signature indels (CSIs) in their proteins: cyclophilin-like protein and mitochondrial inner membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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