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Drillia Tholos
''Drillia tholos'' is a species of sea snail, a marine gastropod mollusk in the family Drilliidae.Sartori, André F. (2015). Drillia tholos Barnard, 1958. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=762247 on 2016-09-10 Description Drillia tholos is a species of marine snail native to Natal, California. Dead Drillia tholos often form shallow marine sediments. The shells attain lengths of 5 mm, its diameter 2 mm, dextrally coiled. Distribution This species occurs in the demersal zone off East London East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. Etymology As in other languages, the word is formed from the f ..., South Africa. References Barnard K.H. (1958), Contribution to the knowledge of South African marine Mollusca. Part 1. Gastropod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. 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. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists 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. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...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] |
Gastropod
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 re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The gas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family ( la, familia, plural ') is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, but in plants, they can be characterized on the basis of both vegetative and reproductive features of plant species. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drilliidae
The Drilliidae are a Taxonomy (biology), taxonomic family (biology), family of small predatory sea snails with high-spired shells. They are classified as marine (ocean), marine gastropod mollusks in the superfamily Conoidea. This family has no subfamilies. It consists of about 30 genera and approximately 500 Recent species. Description The shell is claviform with a tall spire, or squatly conical to biconical. In many species, the siphonal canal is truncated. The aperture (mollusc), aperture is U-shaped with a parietal callus pad. The sculpture of the shell shows prominent axial ribs with a polished surface. Most species have a dorsal varix (mollusc), varix (transverse elevation), except in the genera ''Cymatosyrinx'', ''Elaeocyma'' and ''Splendrillia''. The protoconch can be smooth or very carinate. The ovate operculum (gastropod), operculum has a terminal nucleus. The radula of the species in this family have characteristically five teeth in each row (formula : 1 + 1 + 1 + 1 + ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dextral Coiling
The gastropod shell is part of the body of a 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, 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. The calcareous central layer, tracum, is typically made of calcium carbonate precipitated into an organic matrix known as conchiolin. The outermost layer is the periostra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demersal Zone
The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of the larger profundal zone. Being just above the ocean floor, the demersal zone is variable in depth and can be part of the photic zone where light can penetrate, and photosynthetic organisms grow, or the aphotic zone, which begins between depths of roughly and extends to the ocean depths, where no light penetrates. Fish The distinction between demersal species of fish and pelagic species is not always clear cut. The Atlantic cod (''Gadus morhua'') is a typical demersal fish, but can also be found in the open water column, and the Atlantic herring (''Clupea harengus'') is predominantly a pelagic species but forms large aggregations near the seabed when it spawns on banks of gravel. Two types of fish inhabit the demersal zone: those t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East London, Eastern Cape
East London ( xh, eMonti; af, Oos-Londen) is a city on the southeast coast of South Africa in the Buffalo City Metropolitan Municipality of the Eastern Cape province. The city lies on the Indian Ocean coast, largely between the Buffalo River (Eastern Cape), Buffalo River and the Nahoon River, and hosts the country's only river port. , East London had a population of over 267,000 with over 755,000 in the metropolitan area. History Early history John Bailie, one of the 1820 Settlers, surveyed the Buffalo River (Eastern Cape), Buffalo River mouth and founded the town in 1836. There is a memorial on Signal Hill commemorating the event. The city formed around the only river port in South Africa and was originally known as Port Rex. Later it was renamed London in honour of the capital city of the United Kingdom, hence the name East London. This settlement on the West Bank was the nucleus of the town of East London, which was elevated to city status in 1914. During the early to mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Molluscs Of South Africa
Endemism is the state of a species being found 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 be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drillia
''Drillia'' is a genus of small sea snails, marine gastropod mollusks in the family Drilliidae. General characteristics The shell is turriculated, with an elevated spire, longitudinal ribs, and usually revolving striae. The spiral sculpture of the shell is rather smooth or shows a wide spacing of incised lines. The body whorl is usually short. The columella has a posterior callus. The outer lip is thick, but not varicose, nor dentate within, flexuous, with a well-marked posterior anal sinus near (but not reaching) the suture, and an anterior constriction or sinuosity. The siphonal canal is short, curved and usually narrow. Some species show an interrupted pink banding. The animal has tentacles approaching at their bases and eyes near their extremities. Species Species within the genus ''Drillia'' include: * '' Drillia acapulcana'' (Lowe, 1935) * '' Drillia adusta'' (G.B. I Sowerby, 1834) * † '' Drillia aegyptiaca'' Cossmann, 1901 * ''Drillia aerope'' (Dall, 1919) * ''Drilli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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