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Alvania Novarensis
''Alvania novarensis'' is a species of small sea snail, a marine gastropod mollusk or micromollusk in the family Rissoidae.MolluscaBase eds. (2024). MolluscaBase. Alvania novarensis Frauenfeld, 1867. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=594815 on 2024-01-27 Description The length of the shell attains 2.5 mm. (Described as ''Rissoa (Alvania) trajectus'') The small, white shell is strong, conic-obovate and reticulated. It has a tumid body whorl, a broad round base, a short spire, a few conical whorls, an excavated suture, and a short pear-shaped aperture. Sculpture: Longitudinals — there are on the body whorl about 18 narrow, well-raised, rounded, slightly oblique ribs, which stop abruptly at the periphery. They are not present in the sutural channel, nor almost at all on the base. They are crowded on the earlier whorls, but on the body whorl the flat furrows which part them are wider than the ribs. ... [...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] |
Varix (mollusc)
A varix (: varices) is an anatomical feature of the gastropod shell, shell of certain sea snails, marine (ocean), marine gastropod molluscs. Gastropods whose shells have varices are primarily families and species within the Taxonomy (biology), taxonomic groups Littorinimorpha and Neogastropoda. The varix is a thickened axial ridge, a subcylindrical protrusion, in the Exoskeleton, shell which exists in some families of marine gastropods. It is an important shell character in generic classification. A varix is located at intervals around the Whorl (mollusc), whorl, and is formed by considerable thickening of the outer lip during a resting stage in the growth of the shell. In other words, in gastropods whose shells have varices, the shells are characterised by episodic growth - the shell grows in spurts, and during the resting phase the varix forms. In many gastropod whose shells have varices, for example the Cassinae, the varix is essentially merely a thickening and swelling of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alvania
''Alvania'' is a genus of minute sea snails, marine gastropod mollusks or micromollusks in the family Rissoidae. They form a very diversified group within the Rissoidae family. Description ''Alvania'' as currently used may not be monophyletic. The genus ''Alvinia'' has been synonymized with ''Alvania'', until a consistent phylogenetic scheme emerges for the whole group. , is sometimes considered a separate genus.Gofas, S. (2012). Alvinia Monterosato, 1884. Accessed through: World Register of Marine * At http://www.marinespecies.org/aphia.php?p=taxdetails&id=574680 on 18 June 2012 The genus Alvania comprises species with small shells with heights measuring between 1 mm and 7 mm. Their general shape is ovate-conical, reticulated with axial and spirals elements. They have a continuous peristome. Their coloration is variable. Some species such as '' Alvania sculptilis'' have been named twice with the second naming becoming a junior secondary homonym. However, the genus ''Alv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Australia
Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Australia is Australia's largest state, with a land area of , and is also the List of country subdivisions by area, second-largest subdivision of any country on Earth. Western Australia has a diverse range of climates, including tropical conditions in the Kimberley (Western Australia), Kimberley, deserts in the interior (including the Great Sandy Desert, Little Sandy Desert, Gibson Desert, and Great Victoria Desert) and a Mediterranean climate on the south-west and southern coastal areas. the state has 2.965 million inhabitants—10.9 percent of the national total. Over 90 percent of the state's population live in the South-West Land Division, south-west corner and around 80 percent live in the state capital Perth, leaving the remainder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victoria (state)
Victoria, commonly abbreviated as Vic, is a States and territories of Australia, state in southeastern Australia. It is the second-smallest state (after Tasmania), with a land area of ; the second-most-populated state (after New South Wales), with a population of over 7 million; and the most densely populated state in Australia (30.6 per km2). Victoria's economy is the List of Australian states and territories by gross state product, second-largest among Australian states and is highly diversified, with service sectors predominating. Victoria is bordered by New South Wales to the north and South Australia to the west and is bounded by the Bass Strait to the south (with the exception of a small land border with Tasmania located along Boundary Islet), the Southern Ocean to the southwest, and the Tasman Sea (a marginal sea of the South Pacific Ocean) to the southeast. The state encompasses a range of climates and geographical features from its temperate climate, temperate coa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queensland
Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south, respectively. To the east, Queensland is bordered by the Coral Sea and the Pacific Ocean; to the state's north is the Torres Strait, separating the Australian mainland from Papua New Guinea, and the Gulf of Carpentaria to the north-west. With an area of , Queensland is the world's List of country subdivisions by area, sixth-largest subnational entity; it List of countries and dependencies by area, is larger than all but 16 countries. Due to its size, Queensland's geographical features and climates are diverse, and include tropical rainforests, rivers, coral reefs, mountain ranges and white sandy beaches in its Tropical climate, tropical and Humid subtropical climate, sub-tropical c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Territory
The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regions of Australia. The Northern Territory shares its borders with Western Australia to the west (129th meridian east), South Australia to the south (26th parallel south), and Queensland to the east (138th meridian east). To the north, the Northern Territory looks out to the Timor Sea, the Arafura Sea, and the Gulf of Carpentaria, including Western New Guinea and various other islands of the Indonesian archipelago. The NT covers , making it the third-largest Australian federal division, and List of country subdivisions by area, the 11th-largest country subdivision in the world. It is sparsely populated, with a population of only 249,000 – fewer than half the population of Tasmania. The largest population centre is the capital city of Darw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New South Wales
New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South Australia to the west. Its coast borders the Coral Sea, Coral and Tasman Seas to the east. The Australian Capital Territory and Jervis Bay Territory are Enclave and exclave, enclaves within the state. New South Wales' state capital is Sydney, which is also Australia's most populous city. , the population of New South Wales was over 8.3 million, making it Australia's most populous state. Almost two-thirds of the state's population, 5.3 million, live in the Greater Sydney area. The Colony of New South Wales was founded as a British penal colony in 1788. It originally comprised more than half of the Australian mainland with its Western Australia border, western boundary set at 129th meridian east in 1825. The colony then also includ ... [...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] |
Lip (gastropod)
In the shell of gastropod mollusks (a snail shell), the lip is the free margin of the peristome (synonym: peritreme) or aperture (mollusc), 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 ... [...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] |
