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Troglobites
A troglobite (or, formally, troglobiont) is an animal species, or population of a species, strictly bound to underground habitats, such as caves. These are separate from species that mainly live in above-ground habitats but are also able to live underground (eutroglophiles), and species that are only cave visitors (subtroglophiles and trogloxenes). Land-dwelling troglobites may be referred to as troglofauna, while aquatic species may be called stygofauna, although for these animals the term ''stygobite'' is preferable. Troglobites typically have evolutionary adaptations to cave life. Examples of such adaptations include slow metabolism, reduced energy consumption, better food usage efficiency, decrease or loss of eyesight (anophthalmia), and depigmentation (absence of pigment in the integument). Conversely, as opposed to lost or reduced functions, many species have evolved elongated antenna and locomotory appendages, in order to better move around and respond to environmental st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troglofauna
Troglofauna are small cave-dwelling animals that have adapted to their dark surroundings. Troglofauna and stygofauna are the two types of subterranean fauna (based on life-history). Both are associated with subterranean environments – troglofauna are associated with caves and spaces above the water table and stygofauna with water. Troglofaunal species include spiders, insects, myriapods and others. Some troglofauna live permanently underground and cannot survive outside the cave environment. Troglofauna adaptations and characteristics include a heightened sense of hearing, touch and smell. Loss of under-used senses is apparent in the lack of pigmentation as well as eyesight in most troglofauna. Troglofauna insects may exhibit a lack of wings and longer appendages. Ecological categories Troglofauna are divided into three main categories based on their ecology: * Troglobionts (or troglobites): species, or populations of species, strictly bound to subterranean habitats. * Troglophi ... [...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] |
Sensory Receptors
Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord. The sensory information travels on the afferent nerve fibers in a sensory nerve, to the brain via the spinal cord. The stimulus can come from ''exteroreceptors'' outside the body, for example those that detect light and sound, or from ''interoreceptors'' inside the body, for example those that are responsive to blood pressure or the sense of body position. Types and function Different types of sensory neurons have different sensory receptors that respond to different kinds of stimuli. There are at least six external and two internal sensory receptors: External receptors External receptors that respond to stimuli from outside the body are called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mimic Cavesnail
The mimic cavesnail, scientific name ''Phreatodrobia imitata'', is a species of very small or minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.Hershler R. & Thompson F. G. (1990). "''Antrorbis breweri'', a new genus and species of hydrobiid cavesnail (Gastropoda) from Coosa River Basin, northeastern Alabama". ''Proceedings of the Biological Society of Washington'' 103(l): 197-204PDF Distribution This species is endemic to the United States. Type locality is Verstraeten Well, Bexar County, Texas. Description The shell has 3.3-3.5 whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral .... The average height of the shell is 1.01-1.03 mm. References Lithoglyphidae Gastropods described in 1986 Taxonomy art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phantom Cave Snail
The phantom cave snail or phantom cavesnail (''Pyrgulopsis texana'') is a species of very small freshwater snail with an operculum, an aquatic gastropod in the family Hydrobiidae. Distribution This species is endemic to the lower Pecos River basin, Texas, the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori .... Genus transfer When originally described in 1935, the phantom cave snail was assigned to the genus ''Cochliopa''. Following a detailed examination of shell and anatomical characteristics along with genetic sequencing it was transferred to the genus ''Pyrgulopsis'' in 2010. References Further reading * Dundee D. S. & Dundee H. A. (1969). "Notes Concerning Two Texas Molluscs, ''Cochliopa texana'' Pilsbry and ''Lyrodes cheatumi'' Pilsbry (Mollusca: Hydrob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cave Physa
A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called ''exogene'' caves. Caves which extend further underground than the opening is wide are called ''endogene'' caves. Speleology is the science of exploration and study of all aspects of caves and the cave environment. Visiting or exploring caves for recreation may be called ''caving'', ''potholing'', or ''spelunking''. Formation types The formation and development of caves is known as ''speleogenesis''; it can occur over the course of millions of years. Caves can range widely in size, and are formed by various geological processes. These may involve a combination of chemical processes, erosion by water, tectonic forces, microorganisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumbling Creek Cavesnail
The Tumbling Creek cavesnail (''Antrobia culveri'') is a species of freshwater cave snail with gills and an operculum, an aquatic gastropod mollusk in the family Amnicolidae.Bouchet, P. (2014). Antrobia culveri Hubricht, 1971. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=729787 on 2015-02-19 ''Antrobia culveri'' is the only species in the genus ''Antrobia''.Kabat A. R. & Hershler R. (1993). "The prosobranch snail family Hydrobiidae (Gastropoda: Rissooidea): review of classification and supraspecific taxa". ''Smithsonian Contributions to Zoology'' 547: 1-94PDF This is an endangered species. The common name refers to Tumbling Creek Cave, a National Natural Landmark, in Taney County, Missouri, US Taxonomy The Tumbling Creek cavesnail was described as a new species by Leslie Hubricht in 1971, from specimens taken by David Culver, Thomas Aley, and Hubricht in 1969 and 1970. ''Antrobia culveri'' is the type species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
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 gastropod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hausera
''Hausera'' is a subterranean genus of planarian from Brazil. It contains only the single species ''Hausera hauseri''. It is the first cave-dwelling member of the suborder Cavernicola to have been observed in South America. Etymology Both the genus and species were named after Josef Hauser, a researcher of freshwater flatworms. Description Specimens are long and wide. The pharynx is long, and along with the gonopore is located in the hindmost third of the body. While it lacks eyes, the head has a pair of ciliated sensory organs approximately 140 µm back from the body's anterior end. The intestine extends into the brain and connects with the reproductive system via a genito-intestinal duct. The testicular follicles are arranged in uneven rows near the margins of the body, and the ovaries are located behind but in proximity to the brain, approximately 0.6 millimeters behind the body's tip. The species is colorless. Range and habitat ''Hausera hauseri'' was found i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flatworm
The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Unlike other bilaterians, they are acoelomates (having no body cavity), and have no specialized circulatory and respiratory organ (anatomy), organs, which restricts them to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion (intake of nutrients) and egestion (removal of undigested wastes); as a result, the food cannot be processed continuously. In traditional medicinal texts, Platyhelminthes are divided into Turbellaria, which are mostly non-parasitic animals such as planarians, and three entirely parasitic groups: Cestoda, Trematoda and Monogenea; however, since the turbellarians have since been prove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypogeal
Hypogeal, hypogean, hypogeic and hypogeous (; ) are biological terms describing an organism's activity below the soil surface. In botany, a seed is described as showing hypogeal germination when the cotyledons of the germinating seed remain non-photosynthetic, inside the seed shell, and below ground.{{cite book, author1=Adrian D. Bell, author2=Alan Bryan, title=Plant Form: An Illustrated Guide to Flowering Plant Morphology, url=https://books.google.com/books?id=SM3khPHXhKEC&pg=PA200, year=2008, publisher=Timber Press, isbn=978-0-88192-850-1, page=200 The converse, where the cotyledons expand, throw off the seed shell and become photosynthetic above the ground, is epigeal germination. In water purification works, the hypogeal (or Schmutzdecke) layer is a biological film just below the surface of slow sand filters. It contains microorganisms that remove bacteria and trap contaminant particles. The terms hypogean and hypogeic are used for fossorial ( burrowing) and troglobitic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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