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Hexaplex Duplex
''Hexaplex duplex'' is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails. Subspecies Both subspecies are now considered synonyms of ''Hexaplex duplex''. *''Hexaplex duplex duplex'' (Röding, 1798) – synonyms: ''Murex eurystomus'' Swainson, 1833; ''Murex hoplites'' Fischer, 1876; ''Murex minima'' Dautzenberg, 1910; ''Murex saxatilis'' Linnaeus (auctt.); ''Purpura duplex'' Röding, 1798 *''Hexaplex duplex canariensis'' (Nordsieck, 1975) – synonyms: ''Murex turbinatus'' Lamarck, 1822; ''Trunculariopsis canariensis'' Nordsieck, 1975 Description The length of the shell varies between . It contains six to eight varices. These are singly spinous, the spines somewhat frondose, those on the shoulder of the whorls usually larger and curved. There are no interstitial ribs. The color of the shell is light yellowish brown, usually more or less pink-banded. The aperture is pink, with three or four darker bands. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod Shell
The gastropod shell is part of the body of a Gastropoda, gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the Aperture (mollusc), aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group. Shell layers The gastropod shell has three major layers secreted by the Mantle (mollusc), mantle. The calcareous central layer, tracum, is typically made of calcium carbonate precipitated into an organic matrix known as c ... [...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. Anatomy Sea snails are a very large group of animals and a very diverse one. 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 when they can move around in the air. These air-breathing species includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropods Described In 1798
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, and land snails and slugs. The class Gastropoda 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 65,000 to 80,000 living snail and slug species. The anatomy, behavior, feeding, and reproduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the east by the Levant. The Sea has played a central role in the history of Western civilization. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccated over a period of some 600,000 years during the Messinian salinity crisis before being refilled by the Zanclean flood about 5.3 million years ago. The Mediterranean Sea covers an area of about , representing 0.7% of the global ocean surface, but its connection to the Atlantic via the Strait of Gibraltar—the narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates the Iberian Peninsula in Europe from Morocco in Africa—is only wide. The Mediterranean Sea e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angola
, national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordinates = , largest_city = capital , official_languages = Portuguese , languages2_type = National languages , languages2 = , ethnic_groups = , ethnic_groups_ref = , ethnic_groups_year = 2000 , demonym = , government_type = Unitary dominant-party presidential republic , leader_title1 = President , leader_name1 = João Lourenço , leader_title2 = Vice President , leader_name2 = Esperança da CostaInvestidura do Pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canary Islands
The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocco. They are the southernmost of the autonomous communities of Spain. The islands have a population of 2.2 million people and they are the most populous special territory of the European Union. The seven main islands are (from largest to smallest in area) Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, and El Hierro. The archipelago includes many smaller islands and islets, including La Graciosa, Alegranza, Isla de Lobos, Montaña Clara, Roque del Oeste, and Roque del Este. It also includes a number of rocks, including those of Salmor, Fasnia, Bonanza, Garachico, and Anaga. In ancient times, the island chain was often referred to as "the Fortunate Isles". The Canary Islands are the southernmost region of Spain, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cape Verdes
, national_anthem = () , official_languages = Portuguese , national_languages = Cape Verdean Creole , capital = Praia , coordinates = , largest_city = capital , demonym = Cape Verdean or Cabo Verdean , ethnic_groups_year = 2017 , government_type = Unitary semi-presidential republic , leader_title1 = President , leader_name1 = José Maria Neves , leader_title2 = Prime Minister , leader_name2 = Ulisses Correia e Silva , legislature = National Assembly , area_rank = 166th , area_km2 = 4033 , area_sq_mi = 1,557 , percent_water = negligible , population_census = 561,901 , population_census_rank = 172nd , population_census_year = 2021 , population_density_km2 = 123.7 , population_density_sq_mi = 325.0 , population_density_rank = 89th , GDP_PPP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Sea
The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; Tigrinya: ቀይሕ ባሕሪ ''Qeyih Bahri''; ) is a seawater inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab el Mandeb strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez (leading to the Suez Canal). It is underlain by the Red Sea Rift, which is part of the Great Rift Valley. The Red Sea has a surface area of roughly 438,000 km2 (169,100 mi2), is about 2250 km (1398 mi) long, and — at its widest point — 355 km (220.6 mi) wide. It has an average depth of 490 m (1,608 ft), and in the central ''Suakin Trough'' it reaches its maximum depth of . The Red Sea also has exten ... [...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 prosobranch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral 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 conical tube, the growth of which is coiled into an overall 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 shell has numerous whorls. When the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frondose
Frondosity (from Latin ''frondōsus'' meaning 'leafy') is the property of an organism that normally flourishes with fronds or leaf-like structures. Many frondose organisms are thalloid and lack the organization of tissues into organs, with the exception of ferns. Frondosity is significant mainly for distinguishing particular types of macroscopic algae, and in paleobotany and paleontology, by analyzing features present in fossil biota. Frondose macroalgae are relevant to the ecology of many marine and coastal ecosystems. Large frondose algae play an important role in the creation and functioning of healthy ecosystems from kelp forests to similar habitats. Yet, in coral reefs, frondose seaweed can be recognized as harmful due to the link between excessive blooms and coastal eutrophication. Ediacaran biota The fossil record from the Ediacaran Period is sparse, as more easily fossilized hard-shelled animals had yet to evolve. Most fossils of the time are only faint impressi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varix (mollusc)
A varix () is an anatomical feature of the shell of certain sea snails, marine gastropod molluscs. Gastropods whose shells have varices are primarily families and species within the taxonomic groups Littorinimorpha and Neogastropoda. The varix is a thickened axial ridge, a subcylindrical protrusion, in the 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, 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 the shell at that point. But in some genera within the family Muricidae, such as ''Chicoreu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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