Amastra Magna
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Amastra Magna
''Amastra magna'' is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Amastridae. ;Subspecies: * ''Amastra magna balteata'' Hyatt & Pilsbry, 1911 * ''Amastra magna magna'' (C. B. Adams, 1851) Description The shell is robust, ovate-conic, and elongate, with a distinct coloration: blackish-brown at the apex, transitioning to reddish-brown on the middle whorls, and ash-colored on the lower whorls. Its surface is adorned with irregular, coarse, and unequal transverse striae, accompanied by closely spaced, arcuate ribs near the apex. Indistinct raised spiral lines are present on the lower portion of the body whorl. The apex is subacute, and the spire is relatively long, featuring gracefully curvilinear outlines. The shell is composed of seven slightly convex whorls with a well-defined, deeply impressed suture. The body whorl is obtusely angular. The aperture is ovate and sharply acute at the upper end, with an extremely thickened deposit ...
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Charles Baker Adams
Charles Baker Adams (January 11, 1814 – January 19, 1853) was an American educator and naturalist. Biography He was born in Dorchester, Massachusetts in 1814, the son of Charles J. Adams and Hannah Baker. He graduated from Phillips Academy in 1830 and Amherst College in 1834 with high honors (having transferred from Yale University to Amherst in 1832), and became an assistant to Edward Hitchcock in the Geological Survey of New York in 1836. In 1837, he became a tutor and a lecturer in geology at Amherst College. He left to become professor of chemistry and natural history at Middlebury College in 1838, remaining in that position through 1847. He served as the first state geologist of Vermont from 1845 through 1848. In 1847, he left Middlebury to become professor of astronomy, zoology, and natural history at Amherst College, a position he retained till his death in 1853, aged 39. He visited the West Indies several times in the interest of science, and wrote on conchology. He was ...
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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 ...
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Lanai
Lānai is the sixth-largest of the Hawaiian Islands and the smallest publicly accessible inhabited island in the chain. It is colloquially known as the Pineapple Island because of its past as an island-wide pineapple plantation. The island's only settlement of note is the small town of Lānai City. The island is 98% owned by Larry Ellison, cofounder and chairman of Oracle Corporation; the remaining 2% is owned by the state of Hawaii or individual homeowners. Lānai has a land area of , making it the 43rd largest island in the United States. It is separated from the island of Molokai by the Kalohi Channel to the north, and from Maui by the Auau Channel to the east. The United States Census Bureau defines Lānai as Census Tract 316 of Maui County. Its total population rose to 3,367 as of the 2020 United States census, up from 3,193 as of the 2000 census and 3,131 as of the 2010 census. As visible via satellite imagery, many of the island's landmarks are accessible only by ...
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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 ...
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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 ...
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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 ...
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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 which a s ...
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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 ...
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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 ...
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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 ...
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Amastridae
Amastridae is a Taxonomy (biology), taxonomic family (biology), family of small, air-breathing, land snails, Terrestrial animal, terrestrial pulmonate gastropod mollusks in the superfamily Pupilloidea.MolluscaBase eds. (2021). MolluscaBase. Amastridae Pilsbry, 1910. Accessed through: World Register of Marine Species at: http://marinespecies.org/aphia.php?p=taxdetails&id=994718 on 2021-02-21 Distribution This family is endemism, endemic to the Hawaiian Islands. Genera ;Subfamily Amastrinae Pilsbry, 1910 * ''Amastra'' H. Adams & A. Adams, 1855 * ''Carelia (gastropod), Carelia'' H. Adams & A. Adams, 1855 * ''Cyclamastra'' Pilsbry & Vanatta, 1905 : synonym of ''Amastra (Cyclamastra)'' Pilsbry & Vanatta, 1905 represented as ''Amastra'' H. Adams & A. Adams, 1855 * ''Kauaia'' Sykes, 1900: synonym of ''Amastra (Kauaia)'' Sykes, 1900 represented as ''Amastra'' H. Adams & A. Adams, 1855 (unaccepted rank) * ''Laminella'' L. Pfeiffer, 1854 * ''Planamastra'' Hyatt & Pilsbry, 1911 * ''Tropidop ...
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Mollusc
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 ...
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