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Rhynchobdellida
Rhynchobdellida (from the Greek ''rhynchos'', mouth, and ''bdellein'', sucking), the jawless leeches or freshwater leeches, are an order of aquatic leeches. Despite the common name "freshwater leeches", species are found in both sea and fresh water. They are defined by the presence of a protrusible proboscis instead of jaws, and having colourless blood. They move by "inchworming" and are found worldwide. The order contains 110 species, divided into 41 genera and three families. Members of the order range widely in length, usually between 7 and 40 mm. They are hermaphrodite. The order is not monophyletic. Appearance and eating habits Instead of jaws and teeth, Rhynchobdellidae have protrusible proboscises, which they use to penetrate the host's skin. Mouths of Rhynchobdellidae species are small holes from which the proboscis can be protruded. The proboscis then sucks out the desired bodily fluid from the host: usually blood or coelomic fluid in the case of invertebrate vict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leech
Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodies that can lengthen and contract. Both groups are hermaphrodites and have a clitellum, but leeches typically differ from the oligochaetes in having suckers at both ends and in having ring markings that do not correspond with their internal segmentation. The body is muscular and relatively solid, and the coelom, the spacious body cavity found in other annelids, is reduced to small channels. The majority of leeches live in freshwater habitats, while some species can be found in terrestrial or marine environments. The best-known species, such as the medicinal leech, ''Hirudo medicinalis'', are hematophagous, attaching themselves to a host with a sucker and feeding on blood, having first secreted the peptide hirudin to prevent the blood from c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arhynchobdellida
Arhynchobdellida, the proboscisless leeches, are a monophyletic order of leeches. They are defined by the lack of the protrusible proboscis that defines their sister taxon, the Rhynchobdellida.Uttam, Suneha, and Seema Langer.Distribution and Identification key for species of freshwater leech genus Erpobdella Blainville, 1818 (Hirudinida: Arhynchobdellida: Erpobdelliformes: Erpobdellidae)."/ref> Arhynchobdellida is a diverse order, comprimising both aquatic and terrestrial, besides sanguivorous and predatory, leeches. The order is divided into two suborders, Erpobdelliformes and Hirudiniformes (sometimes also called the Pharyngobdelliformes and Gnathobdelliformes, respectively). Taxonomy Historically, the Arhynchobdellida were split into two orders, the Gnathobdellida and the Pharyngobdellida. The Gnathobdellida were jawed and carnivorous of parasitic while the Pharyngobdellida were jawless and carnivorous. Current taxonomy accepts the order Arhynchobdellida and divides into t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozobranchidae
Turtle leeches are a genus, ''Ozobranchus'', of leeches (Hirudinea) that feed exclusively on the blood of turtles.Hutchins, Michael, ed., et al. ''Grzimek's Animal Life Encyclopedia''. Vol. 2. Detroit: Gale, 2003. 978-0-7876-5362-0. pp. 75-83. Only two species – ''Ozobranchus margoi'' and ''Ozobranchus branchiatus'' – are found in the Atlantic coast of the United States and the Gulf of Mexico. Little is known about these leeches due to difficulties in studying their sea turtle hosts.McGowin, Audrey E., et al. "Genetic barcoding of marine leeches (''Ozobranchus'' spp.) from Florida sea turtles and their divergence in host specificity." ''Molecular Ecology Resources'' 11.2 (2011): 271-278. Physiology Species of ''Ozobranchus'' spp. can be very small (down to a few millimeters in length), making them morphologically difficult to distinguish. ''Ozobranchus margoi'' and ''Ozobranchus branchiatus'' are the most anatomically documented. According to researchers from the University ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozobranchus Jantseanus Cropped
Turtle leeches are a genus, ''Ozobranchus'', of leeches (Hirudinea) that feed exclusively on the blood of turtles.Hutchins, Michael, ed., et al. ''Grzimek's Animal Life Encyclopedia''. Vol. 2. Detroit: Gale, 2003. 978-0-7876-5362-0. pp. 75-83. Only two species – ''Ozobranchus margoi'' and ''Ozobranchus branchiatus'' – are found in the Atlantic coast of the United States and the Gulf of Mexico. Little is known about these leeches due to difficulties in studying their sea turtle hosts.McGowin, Audrey E., et al. "Genetic barcoding of marine leeches (''Ozobranchus'' spp.) from Florida sea turtles and their divergence in host specificity." ''Molecular Ecology Resources'' 11.2 (2011): 271-278. Physiology Species of ''Ozobranchus'' spp. can be very small (down to a few millimeters in length), making them morphologically difficult to distinguish. ''Ozobranchus margoi'' and ''Ozobranchus branchiatus'' are the most anatomically documented. According to researchers from the University ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piscicolidae
The Piscicolidae are a family of jawless leeches in the order Rhynchobdellida that are parasitic on fish. They occur in both freshwater and seawater, have cylindrical bodies, and typically have a large, bell-shaped, anterior sucker with which they cling to their host. Some of the leeches in this family have external gills, outgrowths of the body wall projecting laterally, the only group of leeches to exchange gases in this way. Worldwide, around 60 genera and 100 species of leeches are in this family, all parasitic on the blood of marine, estuarine, and freshwater fishes. These leeches are less common in the tropics, and more abundant in temperate and polar waters. Taxonomy Historically, the Piscicolidae have been divided into three subfamilies: the Pontobdellinae, characterised by two pairs of pulsatile vesicles on each urosome segment; the Pontobdellinae, characterised by a single pair of pulsatile vesicles on each urosome segment; and the Platybdellinae, with no pulsatile ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Collins (imprint)
HarperCollins Publishers LLC is one of the Big Five English-language publishing companies, alongside Penguin Random House, Simon & Schuster, Hachette, and Macmillan. The company is headquartered in New York City and is a subsidiary of News Corp. The name is a combination of several publishing firm names: Harper & Row, an American publishing company acquired in 1987—whose own name was the result of an earlier merger of Harper & Brothers (founded in 1817) and Row, Peterson & Company—together with Scottish publishing company William Collins, Sons (founded in 1819), acquired in 1989. The worldwide CEO of HarperCollins is Brian Murray. HarperCollins has publishing groups in the United States, Canada, the United Kingdom, Australia, New Zealand, Brazil, India, and China. The company publishes many different imprints, both former independent publishing houses and new imprints. History Collins Harper Mergers and acquisitions Collins was bought by Rupert Murdoch's News Corpo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anesthetic
An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia — in other words, to result in a temporary loss of sensation or awareness. They may be divided into two broad classes: general anesthetics, which result in a reversible loss of consciousness, and local anesthetics, which cause a reversible loss of sensation for a limited region of the body without necessarily affecting consciousness. A wide variety of drugs are used in modern anesthetic practice. Many are rarely used outside anesthesiology, but others are used commonly in various fields of healthcare. Combinations of anesthetics are sometimes used for their synergistic and additive therapeutic effects. Adverse effects, however, may also be increased. Anesthetics are distinct from analgesics, which block only sensation of painful stimuli. Local anesthetics Local anesthetic agents prevent the transmission of nerve impulses without causi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as ''Talitrus saltator''. Etymology and names The name ''Amphipoda'' comes, via New Latin ', from the Greek roots 'on both/all sides' and 'foot'. This contrasts with the related Isopoda, which have a single kind of thoracic leg. Particularly among anglers, amphipods are known as ''freshwater shrimp'', ''scuds'', or ''sideswimmers''. Description Anatomy The body of an amphipod is divided into 13 segments, which can be grouped into a head, a thorax and an abdomen. The head is fused to the thorax, and bears two pairs of antennae and one pair of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non- salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of higher plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive. Fresh wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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