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Molluscs
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The number of additional fossil species is estimated between 60,000 and 100,000, and 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. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat, as numerous groups are freshwater mollusc, freshwater and even terrestrial molluscs, terrestrial species. 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, neurologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphioctopus Fangsiao
''Amphioctopus fangsiao'', called webfoot octopus, is a species of octopus, a cephalopod belonging to the genus '' Amphioctopus''. It is found in the Pacific Ocean, including off the coasts of New Zealand as well as in the Yellow Sea and surrounding Chinese shores. It is also commercially fished. Individuals of ''A. fangsiao'' that share genetic similarities by region are distributed throughout the Yellow Sea by size. They can also be infected by parasites in genus '' Aggregata'' and ''Octopicola.'' Name The Chinese name for this octopus is ''fanshao'' (飯蛸), meaning "rice octopus", because its eggs resemble grains of rice. The binomial name ''Amphioctopus fangsiao'' is derived from the Chinese name. Distribution This species occurs in the Philippine Sea, the northwest Pacific and off the coast of Japan ( Osaka Bay). The lifespan of this species is approximately a year, typically spawning in the spring and growing linearly after spawning. In Haizhou Bay in the Yellow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helcionelloida
Helcionelloida is an extinct group of ancient molluscs (phylum Mollusca). These are the oldest known conchiferan molluscs, that is, they had a mineralised shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991. Anatomy These animals were torsion (gastropod), untorted and they had a coiled, cone-shaped shell. The majority of species were small (shells being about two millimeters in length and or diameter). Modern reconstructions depict them as resembling snails. The shells of some genera, particularly ''Yochelcionella'', also possessed a "Snorkel (anatomy), snorkel"-like opening which was most likely used for breathing. 2005 taxonomy The Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), taxonomy of the Gastropoda by Bouchet & Rocroi, 2005Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classification and nomenclator of gastropod families''. Malacologia: International ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rostroconchia
The Rostroconchia is a class of extinct molluscs dating from the early Cambrian to the Late Permian. They were initially thought to be bivalves, but were later given their own class. They have a single shell in their larval stage, and the adult typically has a single, pseudo-bivalved shell enclosing the mantle and muscular foot. The anterior part of the shell probably pointed downward and had a gap from which the foot could probably emerge. Rostroconchs probably lived a sedentary semi- infaunal lifestyle. There were probably more than 1,000 species of members of this class. Approximately 3 dozen genera and an even greater number of species have been described. Generally, rostroconchs are small, less than two centimeters in length, but larger forms, found in United States Devonian limestones, can grow to a length of 15 cm. Morphology and lifestyle Externally, rostroconchs look much like bivalves and rostroconchs probably had an extendable muscular foot, indicated by a ... [...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 iden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudofoveata
Caudofoveata is a small class within the phylum Mollusca, also known as Chaetodermomorpha. The class is often combined with Solenogastres and termed Aplacophora, but some studies have cast doubt on the monophyly of this group. Anatomy Caudofoveata are worm-like molluscs ranging 0.02–10 cm in size, but one species, Chaetoderma felderi, can reach 36.5 cm. The foot is completely absent, and instead of a shell their mantle is covered in calcareous spines called sclerites. Ecology Caudofoveates live by burrowing through soft sediment, and feed by lying vertically in the sediment with just the mouthparts exposed and taking in passing organic detritus. During sexual reproduction, the female produces eggs which are fertilized and brooded, and then the larvae swim freely. Diet Caudofoveates are deposit feeders, or more selective detritivores or predators of foraminifera Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solenogastres
The Solenogastres (less often referred to as Neomeniomorpha), common name, commonly known as solenogasters, are a class of small, worm-like, shell-less Mollusca, molluscs (Aplacophora), the other class being the Caudofoveata (Chaetodermomorpha).MolluscaBase eds. (2021). MolluscaBase. Solenogastres. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=2094 on 2021-04-14 Some recent literature and recent molecular evidence, indicates that the Aplacophora may be polyphyletic, and therefore some taxonomists may divide Solenogastres and Caudofoveata into separate classes. Morphology In contrast to many other mollusc classes, aplacophorans have no shell, and are instead covered by aragonite, aragonitic sclerites (calcareous wikt:spicule, spicules), which can be solid or hollow. These spicules can be arranged perpendicular to one another within the cuticle to form a skeleton, stick up to form a palisade, or can lie flat against th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halwaxiida
Halwaxiida or halwaxiids is a proposed clade equivalent to the older orders Sachitida He 1980 and Thambetolepidea Jell 1981, loosely uniting scale-bearing Cambrian animals, which may lie in the stem group to molluscs or lophotrochozoa. Some palaeontologists question the validity of the Halwaxiida clade. Definition and members The name "halwaxiid" was formed by combining the names of two members of the proposed group, '' Halkieria'' and '' Wiwaxia''. The group was defined as a set of Early to Mid Cambrian animals that had: a "chain mail" coat of three concentric bands of small armor plates that are called sclerites; in some cases, a small cap-like shell at the front end and in some cases both ends. Some scientists are unhappy with this loose definition, arguing that such traits may have arisen convergently rather than being inherited from a common ancestor. This objection implies that the group may not be monophyletic, and that their similarities are not biologically equivale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halkieriidae
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 (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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littorina Littorea
The common periwinkle or winkle (''Littorina littorea'') is a species of small edible whelk or sea snail, a marine gastropod mollusc that has gills and an operculum, and is classified within the family Littorinidae, the periwinkles. This is a robust intertidal species with a dark and sometimes banded shell. It is native to the rocky shores of the northeastern, and introduced to the northwestern, Atlantic Ocean. Description The shell is broadly ovate, thick, and sharply pointed except when eroded. The shell contains six to seven whorls with some fine threads and wrinkles. The color varies from grayish to gray-brown, often with dark spiral bands. The base of the columella is white. The shell lacks an umbilicus. The white outer lip is sometimes checkered with brown patches. The inside of the shell is chocolate brown. The width of the shell ranges from at maturity, with an average length of . Shell height can reach up to , [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern Taxonomy (biology), taxonomy". Many of his writings were in Latin; his name is rendered in Latin as and, after his 1761 ennoblement, as . Linnaeus was the son of a curate and was born in Råshult, in the countryside of Småland, southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his ' in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acaenoplax
''Acaenoplax'' is an extinct worm-shaped mollusc known from the Coalbrookdale Formation of Herefordshire, England. It lived in the Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ... period. It was a couple of centimetres long and half a centimetre wide, and comprises serially repeated units with seven or eight shells, and rings of 'spines'. Some of its characters are reminiscent of the polychaete worms, and the character combinations do not place it obviously in the stem of any modern mollusc group, but although it was originally interpreted as a polychaete, this position is untenable for a number of reasons. Morphology The organism resembles a bristled worm, but bears a number of shells on its upper surface. The first shell is cap-like, whereas the others are saddl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruditapes Philippinarum
''Ruditapes philippinarum'', the Manila clam, is an edible species of saltwater clam in the family Veneridae, the Venus clams. Common names include Manila clam, Japanese littleneck clam, Japanese cockle, and Japanese carpet shell.Cohen, A.N. 2011''Venerupis philippinarum''.The Exotics Guide: Non-native Marine Species of the North American Pacific Coast. Center for Research on Aquatic Bioinvasions, Richmond, California, and San Francisco Estuary Institute, Oakland, California. Revised September 2011. In Japan, it is known as ''asari''. In Korea, it is known as ''bajirak''. The clam is commercially harvested, and is the second most important bivalvia, bivalve grown in aquaculture worldwide.Cordero, D., et alPopulation genetics of the Manila clam (Ruditapes philippinarum) introduced in North America and Europe.''Scientific Reports'' 7, Article number: 39745. 3 January 2017. Description The shell of ''Ruditapes philippinarum'' is elongate, oval, and sculptured with radiating ribs.Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
