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Pylochelidae
The Pylochelidae are a family of hermit crabs. Its members are commonly called the 'symmetrical hermit crabs'. They live in all the world's oceans, except the Arctic and the Antarctic, at depths of . Due to their cryptic nature and relative scarcity, only around 60 specimens had been collected before 1987, when a monograph was published detailing a further 400. Description Unlike other hermit crabs, pylochelid hermit crabs are not markedly asymmetrical, with a straight body and equal numbers of appendages on both sides. This characteristic, together with the partial calcification of the abdomen (which is soft in other hermit crabs) led Edward J. Miers, when describing the first species, to consider it to represent a transition between hermit crabs and "Macrura" (long-tailed decapods, such as lobsters and shrimp). Correspondingly, pylochelid hermit crabs do not usually inhabit gastropod shells, but instead withdraw into decayed pieces of wood, stones, tusk shells (especially De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pylochelidae (MNHN-IU-2013-2380)
The Pylochelidae are a family (biology), family of hermit crabs. Its members are commonly called the 'symmetrical hermit crabs'. They live in all the world's oceans, except the Arctic and the Antarctic, at depths of . Due to their crypsis, cryptic nature and relative scarcity, only around 60 specimens had been collected before 1987, when a monograph was published detailing a further 400. Description Unlike other hermit crabs, pylochelid hermit crabs are not markedly asymmetrical, with a straight body and equal numbers of appendages on both sides. This characteristic, together with the partial calcification of the abdomen (which is soft in other hermit crabs) led Edward J. Miers, when describing the first species, to consider it to represent a transition between hermit crabs and "Macrura" (long-tailed Decapoda, decapods, such as lobsters and shrimp). Correspondingly, pylochelid hermit crabs do not usually inhabit gastropod shells, but instead withdraw into decayed pieces of wood, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermit Crab
Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an asymmetric abdomen concealed by a snug-fitting shell. Hermit crabs' soft (non-calcified) abdominal exoskeleton means they must occupy shelter produced by other organisms or risk being defenseless. The strong association between hermit crabs and their shelters has significantly influenced their biology. Almost 800 species carry mobile shelters (most often calcified snail shells); this protective mobility contributes to the diversity and multitude of crustaceans found in almost all marine environments. In most species, development involves metamorphosis from symmetric, free-swimming larvae to morphologically asymmetric, benthic-dwelling, shell-seeking crabs. Such physiological and behavioral extremes facilitate a transition to a sheltered ... [...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] |
Adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by change in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations that interlock with those of the oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claw
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus for gripping a surface as they walk. The pincers of crabs, lobsters and scorpions, more formally known as their chelae, are sometimes called claws. A true claw is made of a hard protein called keratin. Claws are used to catch and hold prey in carnivorous mammals such as cats and dogs, but may also be used for such purposes as digging, climbing trees, self-defense and grooming, in those and other species. Similar appendages that are flat and do not come to a sharp point are called nails instead. Claw-like projections that do not form at the end of digits but spring from other parts of the foot are properly named spurs. Tetrapods In tetrapods, claws are made of keratin and consist of two layers. The unguis is the harder external layer, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Department Of The Environment, Water, Heritage And The Arts
The Department of the Environment, Water, Heritage and the Arts was an Australian Government department that existed between December 2007 and September 2010. Scope Information about the department's functions and/or government funding allocation could be found in the Administrative Arrangements Orders, the annual Portfolio Budget Statements and in the department's annual reports. According to the Administrative Arrangements Order (AAO) made at the department's establishment, the department dealt with: *Environment protection and conservation of biodiversity *Air quality *National fuel quality standards *Land contamination *Meteorology *Administration of the Australian Antarctic Territory, and the Territory of Heard Island and McDonald Islands *Natural, built and movable cultural heritage *Environmental research *Water policy and resources *Cultural affairs, including support for the arts **There was a domestic Return of Indigenous Cultural Property (RICP) program run by DEWHA, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Faunal Directory
The Australian Faunal Directory (AFD) is an online catalogue of taxonomic and biological information on all animal species known to occur within Australia. It is a program of the Department of Climate Change, Energy, the Environment and Water of the Government of Australia. By May 12, 2021, the Australian Faunal Directory has collected information about 126,442 species and subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species .... It includes the data from the discontinued ''Zoological Catalogue of Australia'' and is regularly updated. Started in the 1980s, it set a goal to compile a "list of all Australian fauna including terrestrial vertebrates, ants and marine fauna" and create an "Australian biotaxonomic information system".''Commonwealth Record'', Volume 5, Issues 26-34, p. 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mangrove
A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several plant families. They occur worldwide in the tropics and subtropics and even some temperate coastal areas, mainly between latitudes 30° N and 30° S, with the greatest mangrove area within 5° of the equator. Mangrove plant families first appeared during the Late Cretaceous to Paleocene epochs, and became widely distributed in part due to the plate tectonics, movement of tectonic plates. The oldest known fossils of Nypa fruticans, mangrove palm date to 75 million years ago. Mangroves are salt-tolerant trees, also called halophytes, and are adapted to live in harsh coastal conditions. They contain a complex salt filtration system and a complex root system to cope with saltwater immersion and wave action. They are ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bamboo
Bamboos are a diverse group of evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family. The origin of the word "bamboo" is uncertain, but it probably comes from the Dutch or Portuguese language, which originally borrowed it from Malay or Kannada. In bamboo, as in other grasses, the internodal regions of the stem are usually hollow and the vascular bundles in the cross-section are scattered throughout the stem instead of in a cylindrical arrangement. The dicotyledonous woody xylem is also absent. The absence of secondary growth wood causes the stems of monocots, including the palms and large bamboos, to be columnar rather than tapering. Bamboos include some of the fastest-growing plants in the world, due to a unique rhizome-dependent system. Certain species of bamboo can grow within a 24-hour period, at a rate of almost an hour (equivalent to 1 mm every 90 seco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin Of Marine Science
The ''Bulletin of Marine Science'' is a peer-reviewed scientific journal published by the Rosenstiel School of Marine and Atmospheric Science of the University of Miami. The journal was established in 1951 as the ''Bulletin of Marine Science of the Gulf and Caribbean'' and obtained its current name in 1965. All content is available electronically, and for issues older than three years, free of charge. Scope The ''Bulletin of Marine Science'' covers marine biology, ecology, biological oceanography, fisheries management, marine policy, marine geology, marine geophysics, marine chemistry, atmospheric chemistry, meteorology Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did no ..., and physical oceanography. References External links * {{Official website, http://bullmarsci.o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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