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Varuna Litterata
''Varuna litterata'', also known as the river swimming crab or the peregrine crab, is a euryhaline species of crab native to the Indo-Pacific. It is commonly found in slow-moving or almost stagnant fresh or brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...s in estuarine habitats. References Decapods Crustaceans described in 1798 {{crab-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motility, able to move, can Sexual reproduction, reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of Cell (biology), cells, the blastula, during Embryogenesis, embryonic development. Over 1.5 million Extant taxon, living animal species have been Species description, described—of which around 1 million are Insecta, insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have Ecology, complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a Symmetry in biology#Bilate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans ( Remipedia, Cephalocarida, Branchiopoda) are more closely related to insects and the other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese spider crab with a leg span of up to and a mass of . Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) limbs, and by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malacostraca
Malacostraca (from New Latin; ) is the largest of the six classes of crustaceans, containing about 40,000 living species, divided among 16 orders. Its members, the malacostracans, display a great diversity of body forms and include crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, amphipods, mantis shrimp, tongue-eating lice and many other less familiar animals. They are abundant in all marine environments and have colonised freshwater and terrestrial habitats. They are segmented animals, united by a common body plan comprising 20 body segments (rarely 21), and divided into a head, thorax, and abdomen. Etymology The name Malacostraca was coined by a French zoologist Pierre André Latreille in 1802. He was curator of the arthropod collection at the National Museum of Natural History in Paris. The name comes from the Greek roots (', meaning "soft") and (', meaning "shell"). The name is misleading, since the shell is soft only immediately after moulting, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decapoda
The Decapoda or decapods (literally "ten-footed") are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crabs, lobsters, crayfish, shrimp and prawns. Most decapods are scavengers. The order is estimated to contain nearly 15,000 species in around 2,700 genera, with around 3,300 fossil species. Nearly half of these species are crabs, with the shrimp (about 3,000 species) and Anomura including hermit crabs, porcelain crabs, squat lobsters (about 2500 species) making up the bulk of the remainder. The earliest fossil decapod is the Devonian '' Palaeopalaemon''. Anatomy Decapods can have as many as 38 appendages, arranged in one pair per body segment. As the name Decapoda (from the Greek , ', "ten", and , '' -pod'', "foot") implies, ten of these appendages are considered legs. They are the pereiopods, found on the last five thoracic segments. In many decapods, one pair of these "legs" has enlarged pincers, called chelae, with the leg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleocyemata
Pleocyemata is a suborder of decapod crustaceans, erected by Martin Burkenroad in 1963. Burkenroad's classification replaced the earlier sub-orders of Natantia and Reptantia with the monophyletic groups Dendrobranchiata (prawns) and Pleocyemata. Pleocyemata contains all the members of the Reptantia (including crabs, lobsters, crayfish, and others), as well as the Stenopodidea (which contains the so-called "boxer shrimp" or "barber-pole shrimp"), and Caridea, which contains the true shrimp. Anatomy All members of the Pleocyemata are united by a number of features, the most important of which is that the fertilised eggs are incubated by the female, and remain stuck to the pleopods (swimming legs) until the zoea larvae are ready to hatch. It is this characteristic that gives the group its name. Pleocyemata also possess a lamellar gill structure as opposed to the branches found in the Dendrobranchiata. Systematics The cladogram below shows Pleocyemata as the sister clade to Den ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. They first appeared during the Jurassic Period. Description Crabs are generally covered with a thick exoskeleton, composed primarily of highly mineralized chitin, and armed with a pair of chelae (claws). Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to . Several other groups of crustaceans with similar appearances – such as king crabs and porcelain crabs – are not true crabs, but have evolved features similar to true crabs through a process known as carcinisation. Environment Crabs are found in all of the world's oceans, as well as in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varunidae
The Varunidae are a family of thoracotrematan crabs. The delimitation of this family, part of the taxonomically confusing Grapsoidea, is undergoing revision. For a long time, they were placed at the rank of subfamily in the Grapsidae, but they appear to be closest to '' Macropthalmus'' and the Mictyridae, which are usually placed in the Ocypodoidea. It may thus be better to merge the latter superfamily with the Grapsoidea, retaining the latter name as it is older. That notwithstanding, the revision of the Grapsoidea (in the narrow but apparently still paraphyletic sense) is also not fully completed, as many taxa remain to be restudied. Already, several former Grapsidae genera have been moved to the Varunidae, and others are tentatively placed here pending detailed study. Among the most noteworthy of these is the Chinese mitten crab, ''Eriocheir sinensis''. The genus ''Xenograpsus'', formerly included in the Varunidae, is now placed in its own family, the Xenograpsidae. The foll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varuna (crab)
Varuna (; sa, वरुण, ) is a Hindu god, associated with the sky, oceans and water. In the '' Vedic scriptures'', he is paired with the god Mitra and is the lord of Ṛta (justice) and Satya (truth). Varuna is also mentioned as an Aditya, the sons of the goddess Aditi. In the later Hindu texts like the '' Puranas'', Varuna is also a Dikpala or guardian of the western direction. He is depicted as a youthful man, mounted on Makara (crocodile) and holding a Pasha (noose, rope loop) and a pitcher in his hands. He has multiple wives and fathered many children, including the Vedic sage Vasishtha. He is also mentioned in the Tamil grammar work ''Tolkāppiyam'', as Kadalon the god of sea and rain. He is found in Japanese Buddhist mythology as Suiten. He is also found in Jainism. Etymology In Hindu tradition, the theonym ''Váruṇa'' (Devanagari: वरुण) is described as a derivation from the verbal root ''vṛ'' ("to surround, to cover" or "to restrain, bind") by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johan Christian Fabricius
Johan Christian Fabricius (7 January 1745 – 3 March 1808) was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: insects, arachnids, crustaceans and others. He was a student of Carl Linnaeus, and is considered one of the most important entomologists of the 18th century, having named nearly 10,000 species of animals, and established the basis for the modern insect classification. Biography Johan Christian Fabricius was born on 7 January 1745 at Tønder in the Duchy of Schleswig, where his father was a doctor. He studied at the gymnasium at Altona and entered the University of Copenhagen in 1762. Later the same year he travelled together with his friend and relative Johan Zoëga to Uppsala, where he studied under Carl Linnaeus for two years. On his return, he started work on his , which was finally published in 1775. Throughout this time, he remained dependent on subsidies from his father, who worked as a consultant at Frederiks Hos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the molly (''Poecilia sphenops'') which can live in fresh water, brackish water, or salt water. The green crab ('' Carcinus maenas'') is an example of a euryhaline invertebrate that can live in salt and brackish water. Euryhaline organisms are commonly found in habitats such as estuaries and tide pools where the salinity changes regularly. However, some organisms are euryhaline because their life cycle involves migration between freshwater and marine environments, as is the case with salmon and eels. The opposite of euryhaline organisms are stenohaline ones, which can only survive within a narrow range of salinities. Most freshwater organisms are stenohaline, and will die in seawater, and similarly most marine organisms are stenohaline, and cannot live in fresh water. Osmoregulation Osmoregulation is the active process by which an organism maintains its level of water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indo-Pacific
The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia. It does not include the temperate and polar regions of the Indian and Pacific oceans, nor the Tropical Eastern Pacific, along the Pacific coast of the Americas, which is also a distinct marine realm. The term is especially useful in marine biology, ichthyology, and similar fields, since many marine habitats are continuously connected from Madagascar to Japan and Oceania, and a number of species occur over that range, but are not found in the Atlantic Ocean. The region has an exceptionally high species richness, with the world's highest species richness being found in at its heart in the Coral Triangle, and a remarkable gradient of decreasing species richness radiating outward ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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