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Microtis (gastropod)
''Microtis'' is a genus of sea snails, marine gastropod mollusks in the family Trochidae, the top snails.Bouchet, P. (2012). ''Microtis'' H. Adams & A. Adams, 1850. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=512300 on 2012-11-23 Description The spiral shell is suborbicular and depressed. It has two tuberculated ridges. The spire is slightly projecting. The aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ... is very large, and wider than long. Its interior is pearly within. The columellar margin is spiral and visible as far as the apex of the spire. There is no operculum. Species Species within the genus ''Microtis (gastropod)'' include: * '' Microtis tuberculata'' A. Adams, 1850 The following species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columella (gastropod)
The columella (meaning "little column") or (in older texts) pillar is a central anatomical feature of a coiled snail shell, a gastropod shell. The columella is often only clearly visible as a structure when the shell is broken, sliced in half vertically, or viewed as an X-ray image. The columella runs from the apex of the shell to the midpoint of the undersurface of the shell, or the tip of the siphonal canal in those shells which have a siphonal canal. If a snail shell is visualized as a cone of shelly material which is wrapped around a central axis, then the columella more or less coincides spatially with the central axis of the shell. In the case of shells that have an umbilicus, the columella is a hollow structure. The columella of some groups of gastropod shells can have a number of plications or folds (the columellar fold, plaits or plicae), which are usually visible when looking to the inner lip into the aperture of the shell. These folds can be wide or narrow, promine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Pacific Ocean
South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþaz'' ("south"), possibly related to the same Proto-Indo-European root that the word ''sun'' derived from. Some languages describe south in the same way, from the fact that it is the direction of the sun at noon (in the Northern Hemisphere), like Latin meridies 'noon, south' (from medius 'middle' + dies 'day', cf English meridional), while others describe south as the right-hand side of the rising sun, like Biblical Hebrew תֵּימָן teiman 'south' from יָמִין yamin 'right', Aramaic תַּימנַא taymna from יָמִין yamin 'right' and Syriac ܬܰܝܡܢܳܐ taymna from ܝܰܡܝܺܢܳܐ yamina (hence the name of Yemen, the land to the south/right of the Levant). Navigation By convention, the ''bottom or down-facing side'' of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Australia
The unofficial geographic term Northern Australia includes those parts of Queensland and Western Australia north of latitude 26° and all of the Northern Territory. Those local government areas of Western Australia and Queensland that lie partially in the north are included. Although it comprises 45% of the total area of Australia, Northern Australia has only 5% of the Australian population (1.3 million in 2019). However, it includes several sources of Australian exports, being coal from the Great Dividing Range in Queensland/New South Wales and the natural gas and iron ore of the Pilbara region in WA. It also includes major natural tourist attractions, such as Uluru (Ayers Rock), the Great Barrier Reef and the Kakadu National Park. Geography and climate Almost all of Northern Australia is a huge ancient craton that has not experienced geological upheaval since the end of the Precambrian. The only exception to this generalisation is the Wet Tropics of northern Queenslan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stomatolina Rubra
''Stomatolina rubra'', common name the red stomatolina, is a species of small sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. Description The size of the shell varies between 8 mm and 18 mm. The depressed, rather thin shell has a small, conical spire. It is reddish brown, lighter beneath, or variously variegated. The surface is covered with close fine hair-like spiral striae, and with two low keels above the periphery, the upper one nodose. There is a series of short folds below the suture. The whorls of the spire contain a beaded carina. The wide body whorl is depressed, flattened above, convex below, and impressed at the axis. The large aperture is rounded, very oblique, and iridescent within. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microtis Tuberculata
''Microtis tuberculata'' is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.Bouchet, P. (2012). ''Microtis tuberculata''. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=547310 on 2012-11-23 Description The size of the shell varies between 9 mm and 20 mm. The shell is much depressed, the spire reaches only a trifle above the body whorl. The colour is variable; in both specimens a greenish-grey colour predominates. In the largest one, the top whorls are variegated with crimson and a large patch of the same colour occupies the upper part of the body whorl, near the aperture. The upper part is covered by microscopic spiral rows of darker arrowhead-shaped spots, the basal part is more yellowish. The shell contains about 3½ whorls. The last whorl increases rapidly. They are very convex, with a deep suture, and short subsutural folds. The sculpture consists of a keel a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (gastropod)
The operculum (; ) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails; the structure is found in some marine and freshwater gastropods, and in a minority of terrestrial gastropods, including the families Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae, Pomatiidae, etc. The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. Many families have opercula that are reduced in size, and which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apex (mollusc)
In anatomy, an apex ( adjectival form: apical) is part of the shell of a mollusk. The apex is the pointed tip (the oldest part) of the shell of a gastropod, scaphopod, or cephalopod. The apex is used in end-blown conches. Gastropods The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod. The apex is the first-formed, and therefore the oldest, part of the shell. To be more precise, the apex would usually be where the tip of the embryonic shell or protoconch is situated, if that is still present in the adult shell (often it is lost or eroded away). Coiled gastropod shells The phrase apical whorls, or protoconch, means the whorls that constitute the embryonic shell at the apex of the shell, especially when this is clearly distinguishable from the later whorls of the shell, otherwise known as the teleoconch. Comparison of the apical part and the whole shell of '' Otukaia kiheiziebisu'': File:Calliostoma kiheiziebisu apex.png File:Calli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc. The term ''aperture'' is used for the main opening in gastropod shells, scaphopod shells, and also for '' Nautilus'' and ammonite shells. The word is not used to describe bivalve shells, where a natural opening between the two shell valves in the closed position is usually called a '' gape''. Scaphopod shells are tubular, and thus they have two openings: a main anterior aperture and a smaller posterior aperture. As well as the aperture, some gastropod shells have additional openings in their shells for respiration; this is the case in some Fissurellidae (keyhole limpets) where the central smaller opening at the apex of the shell is called an orifice, and in the Haliotidae (abalones) where the row of respiratory openings in the shell are also called orifices. In gastropods In some pros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Snail
Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the absence of a visible 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 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'') are sometimes considered to be sea snails and sometimes listed as land snails A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known .... Anatomy Sea snails are a very large group o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spire (mollusc)
A spire is a part of the coiled shell of molluscs. The spire consists of all of the whorls except for the body whorl. Each spire whorl represents a rotation of 360°. A spire is part of the shell of a snail, a gastropod mollusc, a gastropod shell, and also the whorls of the shell in ammonites, which are fossil shelled cephalopods. In textbook illustrations of gastropod shells, the tradition (with a few exceptions) is to show most shells with the spire uppermost on the page. The spire, when it is not damaged or eroded, includes the protoconch (also called the nuclear whorls or the larval shell), and most of the subsequent teleoconch whorls (also called the postnuclear whorls), which gradually increase in area as they are formed. Thus the spire in most gastropods is pointed, the tip being known as the " apex". The word "spire" is used, in an analogy to a church spire or rock spire, a high, thin, pinnacle. The "spire angle" is the angle, as seen from the apex, at wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Register Of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the information, which is gathered from the primary scientific literature as well as from some external regional and taxon-specific databases. WoRMS maintains valid names of all marine organisms, but also provides information on synonyms and invalid names. It is an ongoing task to maintain the registry, since new species are constantly being discovered and described by scientists; in addition, the nomenclature and taxonomy of existing species is often corrected or changed as new research is constantly being published. Subsets of WoRMS content are made available, and can have separate badging and their own home/launch pages, as "subregisters", such as the ''World List ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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