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Argulus Ambystoma
''Argulus ambystoma'' is a species of branchiuran parasitic on Lake Patzcuaro salamanders, sharing that species' very limited range in Lago de Pátzcuaro, Mexico. The male has a total length of 3–4 mm with 2 dark triangular marks on the dorsal surface of the carapace and large dark patches marking the location of the testes. The larger (4–6 mm) female is generally mottled without large dark areas. It lives among the external gills of its neotenous Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compa ... host, only occasionally straying from this hiding place during darkness. This retiring nature may explain why this animal remained undiscovered until recently. References * Freshwater crustaceans of North America Endemic crustaceans of Mexico Crustaceans described in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branchiura
The family Argulidae, whose members are commonly known as carp lice or fish lice, are parasitic crustaceans in the class Ichthyostraca. It is the only family in the monotypic subclass Branchiura and the order Arguloida, although a second family, Dipteropeltidae, has been proposed. Although they are thought to be primitive forms, they have no fossil record. Taxonomy Branchiurans were once thought to be copepods but are now recognised as a separate subclass due to their distinct morphological characteristics.Alan P. Covich, ... D. Christopher Rogers, in Ecology and Classification of North American Freshwater Invertebrates (Third Edition), 2010 There are approximately 170 species in four genera recognised in the family Branchiura. The centres of diversity are the Afrotropical and Neotropical realms. Description Branchiurans have a flattened, oval body, which is almost entirely covered by a broad, oval carapace, four pairs of swimming legs, a pair of anterior compound eyes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Patzcuaro Salamander
The Lake Patzcuaro salamander, locally known as achoque, ''Ambystoma dumerilii'', is a neotenic salamander species. This salamander is found in Lake Pátzcuaro, a high-altitude lake in the Mexican state of Michoacán. This is located in the Mesa Central region of the country, home to many isolated '' Ambystoma'' species. There have been claims that a subspecies is found further inland to the north-east in San Juan del Río, Querétaro, but this is doubtful due to the animal's wholly aquatic nature. ''Dumerilii'' retain their larval characteristics throughout their entire life. This results in adults that have long, heavily filamented external gills, gill slits lined with tooth-like gill rakers, and caudal fins. Patzcuaro salamanders are usually yellowish in color, with a lighter shade on their underbellies. They have large heads and reduced limbs. They are opportunistic suction feeders, and eat many types of invertebrates. Recently, this salamander has been used in research as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lago De Pátzcuaro
__NOTOC__ Lago, which means "lake" in Italian, Portuguese, Spanish and Galician, may refer to: Places *Lago, Calabria, a ''comune'' in the Province of Cosenza, Italy *Lago, Mexico, a municipality zone in the State of Mexico *Lago District, a ''distrito'' in Niassa Province, Mozambique *Lago, Portugal, a ''freguesia'' in the District of Braga *Lago, Asturias, a ''parroquia'' in the ''municipio'' of Allande, Spain *Lago, Texas, a census-designated place *Lagos, Nigeria, the largest city in Nigeria People *Anders Lago, Swedish politician *Ângela Lago (1945–2017), Brazilian children's writer and illustrator *Antonio Lago, Venice-born French motor vehicle manufacturer *Fábio Lago, Brazilian actor *Nais Lago, Italian actress *Virginia Lago (born 1946), Argentine actress Other uses *Lago (Madrid Metro), a station on Line 5 *Talbot-Lago, a type of car *''Lago'', a fictional western town depicted in the film, ''High Plains Drifter'' See also * Lagos (other) * del Lago (dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsum (anatomy)
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carapace
A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron. Crustaceans In crustaceans, the carapace functions as a protective cover over the cephalothorax (i.e., the fused head and thorax, as distinct from the abdomen behind). Where it projects forward beyond the eyes, this projection is called a rostrum (anatomy), rostrum. The carapace is Calcification, calcified to varying degrees in different crustaceans. Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera, ostracods, and Isopoda, isopods, but isopods only have a developed "cephalic shield" carapace covering the head. Arachnids In arachnids, the carapace is formed by the fusion of prosomal tergites into a single Plate (animal anatomy), plate which carries the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testes
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone, whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids of known sizes. Another method is to use cali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (pl. branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamellae (folds) contain blood or coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including mollusks, crustaceans, insects, fish, and amphibians. Semiterrestrial marine animals such as crabs and mudskippers have gill cham ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neotenous
Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compared to other primates. In progenesis or paedogenesis, sexual development is accelerated. Both neoteny and progenesis result in paedomorphism (as having the form typical of children) or paedomorphosis (changing towards forms typical of children), a type of heterochrony. It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders.Schell, S. C. ''Handbook of Trematodes of North America North of Mexico'', 1985, pg. 22 History and etymology The origins of the concept of neoteny have been traced to the Bible (as argued by Ashley M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohio Journal Of Science
The Ohio State University Libraries are the collective libraries of the Ohio State University and its satellite campuses. This system welcomes Ohio State faculty, students, visiting scholars and the general public to study and research. It includes ten libraries located on the Columbus campus, six libraries on the regional campus of the university and nine special collections. The Ohio State University Libraries offer educational resources and services to support readers to research, learn and teach. They can help researchers find and borrow physical and digital materials from articles, journals, databases, books, dissertations, theses, newspapers, streaming videos and images, etc. The Ohio State University libraries hold over six million volumes in traditional library formats and more in electronic information resources. History In 1893, the Ohio State University built the Orton Hall Library, the first library at this university. It holds over 200,000 geologic and topographic m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Crustaceans Of North America
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] |
Endemic Crustaceans Of Mexico
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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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