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Amastra Pullata
''Amastra pullata'' is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Amastridae. ;Subspecies: * ''Amastra pullata pullata'' (Baldwin, 1895) * ''Amastra pullata subnigra'' Hyatt & Pilsbry, 1911 (description: Similar to the preceding species but smaller, the upper portion of the spire is purplish-brown. The undercuticle is orange or pale yellow, partially visible beneath a more or less deciduous blackish outer layer) * ''Amastra pullata umbrosa'' (Baldwin, 1895) Description The length of the shell attains 23 mm, its diameter 11.5 mm. (Original description) The shell contains 7 whorls. The shell is dextral, imperforate, and solid, with an elongately ovate shape. Its surface is lusterless, adorned with irregular, closely spaced growth striae, while the whorls of the protoconch are finely and radially sulcated. The shell's color is light brown, covered by a fugacious black epidermis that is dense on the body whorl but spars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...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 (bivalve), 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 (mollusc), apex of the shell is called an orifice, and in the Haliotidae (abalone) where the row of respiratory openings in the shell are also called orifices. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molokai
Molokai or Molokai ( or ; Molokaʻi dialect: Morotaʻi ) is the fifth most populated of the eight major islands that make up the Hawaiian Islands archipelago in the middle of the Pacific Ocean. It is 38 by 10 miles (61 by 16 km) at its greatest length and width with a usable land area of , making it the fifth-largest in size of the main Hawaiian Islands and the 27th largest island in the United States. It lies southeast of Oʻahu across the wide Kaʻiwi Channel and north of Lānaʻi, separated from it by the Kalohi Channel. The island's agrarian economy has been driven primarily by cattle ranching, pineapple production, sugarcane production and small-scale farming. Tourism comprises a small fraction of the island's economy, and much of the infrastructure related to tourism was closed and barricaded in the early 2000s when the primary landowner, Molokai Ranch, ceased operations due to substantial revenue losses. In Kalawao County, on the Kalaupapa Peninsula on the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only state not on the North American mainland, the only state that is an archipelago, and the only state in the tropics. Hawaii consists of 137 volcanic islands that comprise almost the entire Hawaiian Islands, Hawaiian archipelago (the exception, which is outside the state, is Midway Atoll). Spanning , the state is Physical geography, physiographically and Ethnology, ethnologically part of the Polynesian subregion of Oceania. Hawaii's ocean coastline is consequently the List of U.S. states and territories by coastline, fourth-longest in the U.S., at about . The eight main islands, from northwest to southeast, are Niihau, Niihau, Kauai, Kauai, Oahu, Oahu, Molokai, Molokai, Lanai, Lānai, Kahoʻolawe, Kahoolawe, Maui, and Hawaii (island), Hawaii, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or b ... [...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 (mollusc), 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 (mollusc), aperture of the shell. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peristome (gastropod)
In the shell of gastropod mollusks (a snail shell), the lip is the free margin of the peristome (synonym: peritreme) or aperture (the opening) of the gastropod shell. In dextral (right-handed) shells (most snail shells are right-handed), the right side or outer side of the aperture is known as the outer lip (''labrum''). The left side of the aperture is known as the inner lip or columellar lip (''labium'') if there is a pronounced lip there. In those species where there is no pronounced lip, the part of the body whorl that adjoins the aperture is known as the parietal wall. The outer lip is usually thin and sharp in immature shells, and in some adults (e.g. the land snails ''Helicella'' and ''Bulimulus''). However, in some other land snails and in many marine species the outer lip is ''thickened'' (also called ''callused''), or ''reflected'' (turned outwards). In some other marine species it is curled inwards (''inflected''), as in the cowries such as ''Cypraea''. It can also be e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apex (mollusc)
In anatomy, an apex (adjectival form: apical) is part of the mollusc shell, 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 conch (instrument), conches. Gastropods The word "apex" is most often used to mean the tip of the spire (mollusc), 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:Cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Whorl
The body whorl is part of the morphology (biology), morphology of the gastropod shell, shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the body whorl, or last whorl, is the most recently formed and largest Whorl (mollusc), whorl (or revolution) of a spiral or Helix, helical Gastropod shell, shell, terminating in the Aperture (mollusc), aperture. It is called the "body whorl" because most of the body of the soft parts of the animal fits into this whorl. The proportional size of the body whorl in gastropod shells differs greatly according to the actual shell morphology. For shells in which the rate of whorl expansion of each revolution around the axis is very high, the aperture and the body whorl are large, and the shell tends to be low Spire (mollusc), spired. The shell of the abalone is a good example of this kind of shell. The opposite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Snail
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 molluscs, terrestrial gastropod mollusks that have gastropod shell, shells (those without shells are known as slugs). However, it is not always easy to say which species are terrestrial, because some are more or less amphibious between land and fresh water, and others are relatively amphibious between land and salt water. Land snails are a Polyphyly, polyphyletic group comprising at least ten independent evolutionary transitions to terrestrial life (the last common ancestor of all gastropods was marine). The majority of land snails are pulmonates that have a lung and breathe air. Most of the non-pulmonate land snails belong to lineages in the Caenogastropoda, and tend to have a gill and an operculum (gastropod), operculum. The largest clade of non-pulmonate land snails is the Cyclophoroidea, with more than 7,0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoconch
A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called "nucleus". The protoconch may sometimes consist of several whorl (mollusc), whorls, but when this is the case, the whorls show no growth lines. The whorls of the adult shell, which are formed after the protoconch, are known as the teleoconch. The teleoconch starts forming when the larval gastropod becomes a juvenile, and the protoconch may dissolve. Quite often there is a visible line of demarcation where the protoconch ends and the teleoconch begins, and there may be a noticeable change in Sculpture (mollusc), sculpture, or a sudden appearance of sculpture at that point. In some gastropod groups (such as the Architectonicidae), the teleoconch whorls spiral in the opposite direction to the protoconch. In those cases, the shell is called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral or whorled growth of a mollusc shell. A spiral configuration of the shell is found in numerous gastropods, but it is also found in shelled cephalopods including ''Nautilus'', ''Spirula'' and the large extinct subclass of cephalopods known as the ammonites. A spiral shell can be visualized as consisting of a long Cone (geometry), conical tube, the growth of which is coiled into an overall Helix, helical or planispiral shape, for reasons of both strength and compactness. The number of whorls which exist in an adult shell of a particular species depends on mathematical factors in the geometric growth, as described in D'Arcy Wentworth Thompson's classic 1917 book ''On Growth and Form'', and by David Raup. The main factor is how rapidly the conical tube expands (or flares-out) over time. When the rate of expansion is low, such that each subsequent whorl is not that much wider than the previous one, then the adult s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
