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Gastropods
Gastropods (), commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and from the land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, land snails and slugs. The class Gastropoda is a diverse and highly successful class of mollusks within the phylum Mollusca. It 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 65,00 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vetigastropoda
Vetigastropoda is a major taxonomic group of sea snails, marine gastropod mollusks that form a very ancient lineage. Taxonomically the Vetigastropoda are sometimes treated as an order, although they are treated as an unranked clade in Bouchet and Rocroi, 2005. Vetigastropods are considered to be among the most primitive living gastropods, and are widely distributed in all oceans of the world. Their habitats range from the deep sea to intertidal zones. Many have shells with slits or other secondary openings. One of their main characteristics is the presence of intersected crossed platy shell structure. Most vetigastropods have some bilateral asymmetry of their organ systems. Description Vetigastropods range in size from approximately 0.08 in (2 mm) long in the case of Scissurelloidea or Skeneoidea, to more than 11.8 in (300 mm) in length, as with the Haliotoidea. External colours and patterns are typically drab, but such groups as the Tricolioidea and some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Slug
Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod mollusks) that, over evolutionary time, have either entirely lost their shells or have seemingly lost their shells due to having a significantly reduced or internal shell. The name "sea slug" is often applied to Nudibranch, nudibranchs and a paraphyletic set of other marine gastropods without apparent Gastropod shell, shells. Sea slugs have an enormous variation in body shape, color, and size. Most are partially translucent. The often bright colors of Coral reef, reef-dwelling species imply that these animals are under constant threat of predators. Still, the color can warn other animals of the sea slug's toxic stinging cells (nematocysts) or offensive taste. Like all Gastropod, gastropods, they have small, razor-sharp teeth called Radula, rad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Snail
Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs to major rivers. The great majority of freshwater gastropods have a gastropod shell, shell, with very few exceptions. Some groups of snails that live in freshwater Respiratory system, respire using gills, whereas Pulmonata, other groups need to reach the surface to breathe air. In addition, some are amphibious and have both gills and a lung (e.g. ''Ampullariidae''). Most feed on algae, but many are detritivores and some are Filter feeding, filter feeders. Freshwater snails are indirectly among the deadliest animals to humans, as they carry parasitic worms that cause schistosomiasis, a disease estimated to kill between 10,000 and 200,000 people annually. There are thousands of known species, and at least 33–38 independent Lineage (evolut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
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] |
Heterobranchia
Heterobranchia, the heterobranchs (meaning "different gill"), is a taxonomic clade of snails and slugs, which includes marine, aquatic, and terrestrial gastropod molluscs. Heterobranchia is one of the main clades of gastropods. Currently Heterobranchia comprises two groups: the opisthobranchs, and the pulmonates. Diversity The two subdivisions of this large clade are quite diverse: * Opisthobranchia are virtually all marine species, some shelled and some not, and comprise about 25 families and 2000 species of the bubble shells, the seaslugs, as well as the sea hares. The internal organs of the opisthobranchs have undergone detorsion (unwinding of the viscera that were twisted during torsion). * The Pulmonata comprises about 20000 species, includes the majority of land snails and slugs, many freshwater snails, and a small number of marine species. The mantle cavity of the Pulmonata is modified into an air-breathing organ. They are also characterized by detorsion a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neritimorpha
Neritimorpha is a clade of gastropod molluscs that contains around 2,000 extant species of sea snails, limpets, freshwater snails, land snails and slugs. This clade used to be known as the superorder Neritopsina. Etymology The clade’s name, Neritimorpha, is from the Ancient Greek νηρίτης (nērī́tēs 'Nerite') and μορφή (morphḗ 'form'). Description Despite their relatively low diversity, with only around 2,000 species, neritomorphs have achieved a remarkable diversity of forms, resembling a smaller-scale version of the diversity achieved by Gastropoda as a whole. Terrestrial lifestyles have evolved at least three separate occasions in neritimorphs: the extinct Dawsonellidae and the extant taxon, extant Helicinidae and Hydrocenidae. Neritimorphs also include the shellless, slug-like ''Titiscania''. In all modern neritomorphs except neritopsids, the inner walls of the protoconch are resorbed. Unlike most other gastropods, neritomorphs typically have calcifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slug
Slug, or land slug, is a common name for any apparently shell-less Terrestrial mollusc, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semi-slugs (this is in contrast to the common name ''snail'', which applies to gastropods that have a coiled shell large enough that they can fully retract their soft parts into it). Various Taxonomy (biology), taxonomic families of land slugs form part of several quite different evolutionary lineages, which also include snails. Thus, the various families of slugs are not closely related, despite the superficial similarity in overall body form. The shell-less condition has arisen many times independently as an example of convergent evolution, and thus the category "slug" is Polyphyly, polyphyletic. Taxonomy Of the six orders of Pulmonata, two – the Onchidiacea and Soleoli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Snail
Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the absence of a visible Gastropod shell, shell. Definition Determining whether some gastropods should be called sea snails is not always easy. Some species that live in brackish water (such as certain Neritidae, neritids) can be listed as either freshwater snails or marine snails, and some species that live at or just above the high tide level (for example, species in the genus ''Truncatella (gastropod), Truncatella'') are sometimes considered to be sea snails and sometimes listed as land snails. Anatomy Sea snails are a very large and diverse group of animals. Most snails that live in salt water respire using a gill or gills; a few species, though, have a lung, are intertidal, and are active only at low tide w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snail
A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastropoda that have a coiled gastropod shell, shell that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails. Gastropods that naturally lack a shell, or have only an internal shell, are mostly called ''slugs'', and land snails that have only a very small shell (that they cannot retract into) are often called ''semi-slugs''. Snails have considerable human relevance, including Snails as food, as food items, as pests, and as vectors of disease, and their shells are used as decorative objects and are incorporated into jewellery. The snail has also had some cultural significance, tending t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patellogastropoda
The Patellogastropoda, common name true limpets and historically called the Docoglossa, are members of a major phylogenetic group of marine (ocean), marine gastropods, treated by experts either as a clade or as a taxonomic Order (biology), order. The clade Patellogastropoda is deemed monophyletic based on phylogenetic analysis. Taxonomy Patellogastropoda was proposed by David R. Lindberg, 1986, as an order, and was later included in the subclass Eogastropoda Ponder & Lindberg, 1996. 2005 taxonomy Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), Bouchet & Rocroi, 2005 designated Patellogastropoda, true limpets, as a clade, rather than as a taxon, but within included superfamilies and families as listed below. Families that are exclusively fossil are indicated with a dagger †: * Superfamily Patelloidea ** Family Patellidae * Superfamily Nacelloidea ** Family Nacellidae * Superfamily Lottioidea ** Family Lottiidae ** Family Acmaeidae Forbes, 1850 *** subfamily Acmaeinae For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of '' Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before prin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caenogastropoda
Caenogastropoda is a taxonomic subclass of molluscs in the class Gastropoda. It is a large diverse group which are mostly sea snails and other marine gastropod mollusks, but also includes some freshwater snails and some land snails. The subclass is the most diverse and ecologically successful of the gastropods. Caenogastropoda contains many families of shelled marine molluscs – including the periwinkles, cowries, wentletraps, moon snails, murexes, cone snails and turrids – and constitutes about 60% of all living gastropods. Biology The Caenogastropoda exhibit torsion, and thus are included in what was previously called the Streptoneura (meaning ''twisted nerves''), also known as Prosobranchia (meaning ''gills forward''). Specifically, they are characterized by having only a single auricle in the heart and a single pair of gill leaflets, and are equivalent to the Monotocardia or Pectinibranchia of older authors. Taxonomy The taxon Caenogastropoda was fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
