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Veliger
A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells. Description The veliger is the characteristic larva of the gastropod, bivalve and scaphopod taxonomic classes. It is produced following either the embryonic or trochophore larval stage of development. In bivalves the veliger is sometimes referred to as a D-stage (early in its development) or pediveliger (late in its development) larva. This stage in the life history of these groups is a free-living planktonic organism; this mode of life potentially enhances dispersal to new regions far removed from the adult mollusks that produced the larvae. The general structure of the veliger includes a shell that surrounds the visceral organs of the larva (e.g., digestive tract, much of the nervous system, excretory organs) and a ciliated velum that extends beyond the shell as a single or multi-lobed structure used for swimming and particu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiona Pinnata
''Fiona pinnata'', common name Fiona, is a species of small pelagic nudibranch (sea slug), a marine gastropod mollusk in the superfamily Fionoidea. This nudibranch species lives worldwide on floating objects on seas, and feeds mainly on barnacles, specifically goose barnacles in the genus ''Lepas''. The anatomy of this species is very unusual. It is currently the only named member of the genus ''Fiona'' but a 2016 study showed that this species is a species complex. The family Fionidae was expanded in 2016 to include Tergipedidae, Eubranchidae and Calmidae as a result of a molecular phylogenetics study. Features that are characteristic of the genus ''Fiona'' includeWillan R. C. (1979) "New Zealand locality records for the aeolid nudibranch ''Fiona pinnata'' (Eschscholtz)". ''Tane'' 25: PDF/ref> the similar-looking oral tentacles and rhinophores; the cerata with a membrane and lacking a cnidosac; a dorsal anal opening; a reproductive system with two genital openings; two jaw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prodissoconch
A prodissoconch (meaning first or earliest or original shell) is an embryonic or larval shell which is present in the larva of a bivalve mollusk (clams, scallops, oysters, etc.). (The homologous structure in gastropods (snails) is called the protoconch.) The prodissoconch is often but not always smooth, and has no growth lines. It is sometimes still present and visible in the adult shell, if there has been no erosion of the shell in that area. The structure of the prodissoconch has been widely used as a discriminating feature in bivalve systematics. Position Once the larval bivalve settles and becomes a juvenile, the rest of the shell starts to grow. The earliest part of the shell that formed often shows in the adult shell as a protruding area known as the umbo, at the tip of which is the prodissoconch, assuming it has not been eroded or obscured in some other way. Quite often there is a visible line of demarkation where the prodissoconch ends and the umbo begins, and there ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dreissena Polymorpha
The zebra mussel (''Dreissena polymorpha'') is a small freshwater mussel. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally introduced to numerous other areas and has become an invasive species in many countries worldwide. Since the 1980s, the species has invaded the Great Lakes, Hudson River, and Lake Travis. The species was first described in 1769 by German zoologist Peter Simon Pallas in the Ural, Volga, and Dnieper Rivers. Zebra mussels get their name from a striped pattern commonly seen on their shells, though it is not universally present. They are usually about the size of a fingernail, but can grow to a maximum length around . Shells are D-shaped, and attached to the substrate with strong byssal fibers, which come out of their umbo on the dorsal (hinged) side. Ecology Zebra mussels and the closely related and ecologically similar quagga mussels are filter-feeding organisms; they remove particles from the water column. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc
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 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 phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and 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 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve Anatomy
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 calcium ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nudibranch
Nudibranchs () are a group of soft-bodied marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, such as "clown", "marigold", "splendid", "dancer", "dragon", or "sea rabbit". Currently, about 3,000 valid species of nudibranchs are known.Ocean Portal (2017)A Collage of Nudibranch Colors Smithsonian National Museum of Natural History. Retrieved 17 April 2018. The word "nudibranch" comes from the Latin "naked" and the Ancient Greek () " gills". Nudibranchs are often casually called sea slugs, as they are a family of opistobranchs (sea slugs), within the phylum Mollusca (molluscs), but many sea slugs belong to several taxonomic groups which are not closely related to nudibranchs. A number of these other sea slugs, such as the photosynthetic '' Sacoglossa'' and the colourful Aglajidae, are often confused with nudibranchs. Dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod Anatomy
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, and land snails and slugs. The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian. , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extant with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mollusca, and are the most highly diversified class in the phylum, with 65,000 to 80,000 living snail and slug species. The anatomy, behavior, feeding, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Zoology
The ''Journal of Zoology'' is a scientific journal concerning zoology, the study of animals. It was founded in 1830 by the Zoological Society of London and is published by Wiley-Blackwell. It carries original research papers, which are targeted towards general readers. Some of the articles are available via open access, depending on the author's wishes. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as ... of 2.322, ranking it 36th out of 175 journals in the category "Zoology". From around 1833, it was known as the ''Proceedings of the Zoological Society of London'' (). From 1965 to 1984, it was known as the ''Journal of Zoology: Proceedings of the Zoological Society of London'' (). See also * List o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscera
In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system. An organ's tissues can be broadly categorized as parenchyma, the functional tissue, and stroma, the structural tissue with supportive, connective, or ancillary functions. For example, the gland's tissue that makes the hormones is the parenchyma, whereas the stroma includes the nerves that innervate the parenchyma, the blood vessels that oxygenate and nourish it and carry away its metabolic wastes, and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trochophore
A trochophore (; also spelled trocophore) is a type of free-swimming planktonic marine larva with several bands of cilia. By moving their cilia rapidly, they make a water eddy, to control their movement, and to bring their food closer, to capture it more easily. Occurrence Trochophores exist as a larval form within the trochozoan clade, which include the entoprocts, molluscs, annelids, echiurans, sipunculans and nemerteans. Together, these phyla make up part of the Lophotrochozoa; it is possible that trochophore larvae were present in the life cycle of the group's common ancestor. Etymology The term ''trochophore'' derives from the ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ... (), meaning "wheel", and () — or () —, meaning 'to bear, to carry', b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
