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Branchiopod
Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca (or Cladocera), Notostraca and the Devonian ''Lepidocaris''. They are mostly small, freshwater animals that feed on plankton and detritus. Description Members of the Branchiopoda are unified by the presence of gills on many of the animals' appendages, including some of the mouthparts. This is also responsible for the name of the group (from the grc, βράγχια, gills, akin to , windpipe; el, πούς, foot). They generally possess compound eyes and a carapace, which may be a shell of two valves enclosing the trunk (as in most Cladocera), broad and shallow (as in the Notostraca), or entirely absent (as in the Anostraca). In the groups where the carapace prevents the use of the trunk limbs for swimming (Cladocera, clam shrimp and the extinct Lipostraca), the antennae are used for locomotion, as they are in the nauplius. Male fairy shrimp have an enlarged pair of antennae with which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anostraca
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are referred to as fairy shrimp. They live in vernal pools and hypersaline lakes across the world, and they have even been found in deserts, ice-covered mountain lakes and Antarctic ice. They are usually long (exceptionally up to ). Most species have 20 body segments, bearing 11 pairs of leaf-like ''phyllopodia'' (swimming legs), and the body lacks a carapace. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces. They are an important food for many birds and fish, and some are cultured and harvested for use as fish food. There are 300 species spread across 8 families. Description The body of a fairy shrimp is elongated and divided into segments. The whole animal is typically long, but one species, '' Branchinecta gigas'' does not reach sexual maturity until it reaches long, and can grow to long. The exoskeleton is thin and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarsostraca
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are referred to as fairy shrimp. They live in vernal pools and hypersaline lakes across the world, and they have even been found in deserts, ice-covered mountain lakes and Antarctic ice. They are usually long (exceptionally up to ). Most species have 20 body segments, bearing 11 pairs of leaf-like ''phyllopodia'' (swimming legs), and the body lacks a carapace. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces. They are an important food for many birds and fish, and some are cultured and harvested for use as fish food. There are 300 species spread across 8 families. Description The body of a fairy shrimp is elongated and divided into segments. The whole animal is typically long, but one species, '' Branchinecta gigas'' does not reach sexual maturity until it reaches long, and can grow to long. The exoskeleton is thin and fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllopoda
Branchiopoda is a class (biology), class of crustaceans. It comprises Anostraca, fairy shrimp, clam shrimp, Diplostraca (or Cladocera), Notostraca and the Devonian ''Lepidocaris''. They are mostly small, freshwater animals that feed on plankton and detritus. Description Members of the Branchiopoda are unified by the presence of gills on many of the animals' appendages, including some of the arthropod mouthparts, mouthparts. This is also responsible for the name of the group (from the grc, βράγχια, gills, akin to , windpipe; el, πούς, foot). They generally possess compound eyes and a carapace, which may be a shell of two valves enclosing the trunk (as in most Cladocera), broad and shallow (as in the Notostraca), or entirely absent (as in the Anostraca). In the groups where the carapace prevents the use of the trunk limbs for swimming (Cladocera, clam shrimp and the extinct Lipostraca), the antenna (biology), antennae are used for locomotion, as they are in the naupliu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplostraca
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, even if several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description They are mostly long, with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notostraca
The order Notostraca, containing the single family Triopsidae, is a group of crustaceans known as tadpole shrimp or shield shrimp. The two genera, ''Triops'' and '' Lepidurus'', are considered living fossils, with similar forms having existed since the Devonian. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. The abdomen is long, appears to be segmented and bears numerous pairs of flattened legs. The telson is flanked by a pair of long, thin caudal rami. Phenotypic plasticity within taxa makes species-level identification difficult, and is further compounded by variation in the mode of reproduction. Notostracans are omnivores living on the bottom of temporary pools and shallow lakes. Description Notostracans are long, with a broad carapace at the front end, and a long, slender abdomen. This gives them a similar overall shape to a tadpole, from which the common name ''tadpole shrimp'' derives. The carapace is dorso-ventrally flat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladocera
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, even if several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description They are mostly long, with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipostraca
''Lepidocaris rhyniensis'' is an extinct species of crustacean. It is the only species known from the order Lipostraca, and is the only abundant animal in the Pragian-aged Rhynie chert deposits. It resembles modern Anostraca, to which it is probably closely related, although its relationships to other orders remain unclear. The body is long, with 23 body segments and 19 pairs of appendages, but no carapace. It occurred chiefly among charophytes, probably in alkaline temporary pools. Biostratigraphy and taxonomy All the known specimens of ''Lepidocaris rhyniensis'' have been excavated from the Rhynie chert deposits in Aberdeenshire, Scotland, which is a famous ', or site of exceptional preservation. ''Lepidocaris'' is the only abundant animal in the deposits, and is likely to be responsible for many of the frequent coprolites found in the rocks. ''Lepidocaris'' was first described by D. J. Scourfield in a 1926 paper in the ''Philosophical Transactions of the Royal Society B'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepidocaris
''Lepidocaris rhyniensis'' is an extinct species of crustacean. It is the only species known from the order Lipostraca, and is the only abundant animal in the Pragian-aged Rhynie chert deposits. It resembles modern Anostraca, to which it is probably closely related, although its relationships to other orders remain unclear. The body is long, with 23 body segments and 19 pairs of appendages, but no carapace. It occurred chiefly among charophytes, probably in alkaline temporary pools. Biostratigraphy and taxonomy All the known specimens of ''Lepidocaris rhyniensis'' have been excavated from the Rhynie chert deposits in Aberdeenshire, Scotland, which is a famous ', or site of exceptional preservation. ''Lepidocaris'' is the only abundant animal in the deposits, and is likely to be responsible for many of the frequent coprolites found in the rocks. ''Lepidocaris'' was first described by D. J. Scourfield in a 1926 paper in the '' Philosophical Transactions of the Royal Society B ... [...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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clam Shrimp
Clam shrimp are a group of bivalved branchiopod crustaceans that resemble the unrelated bivalved molluscs. They are extant and also known from the fossil record, from at least the Devonian period and perhaps before. They were originally classified in the former order Conchostraca, which later proved to be paraphyletic and was subsumed into the superorder Diplostraca. Clam shrimp now make up three of the seven orders in Diplostraca, Cyclestherida, Laevicaudata, and Spinicaudata, in addition to the fossil family Leaiidae. Characteristics Both valves of the shell are held together by a strong closing muscle. The animals react to danger by contracting the muscle, so that the valves close tightly and the crustacean, as if dead, lies motionlessly at the bottom of the pool. In most species the head is dorsoventrally compressed. The sessile compound eyes are close together and located on the forehead; in the genus ''Cyclestheria'' they are truly fused. In front of them is a simple n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triops
''Triops'' is a genus of small crustaceans in the order Notostraca (tadpole shrimp). The long-lasting resting eggs of several species of ''Triops'' are commonly sold in kits as a pet. The animals hatch upon contact with fresh water. Most adult-stage ''Triops'' have a life expectancy of up to 90 days and can tolerate a pH range of 6–10. In nature, they often inhabit temporary pools. Relatives and fossil record The genus ''Triops'' can be distinguished from the only other living genus of Notostraca, ''Lepidurus'', by the form of the telson (the end of its 'tail'), which bears only a pair of long, thin caudal extensions in ''Triops'', while ''Lepidurus'' also bears a central platelike process. Only 24 hours after hatching they already resemble miniature versions of the adult form. ''Triops'' are sometimes called "living fossils", since fossils that have been attributed to this genus have been found in rocks hundreds of millions of years old. However, careful analysis of these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nauplius (larva)
Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a ecdysis, moult, in which the hard exoskeleton is shed to allow the animal to grow. The larvae of crustaceans often bear little resemblance to the adult, and there are still cases where it is not known what larvae will grow into what adults. This is especially true of crustaceans which live as benthic adults (on the sea bed), more-so than where the larvae are planktonic, and thereby easily caught. Many crustacean larvae were not immediately recognised as larvae when they were discovered, and were described as new genera and species. The names of these genera have become generalised to cover specific larval stages across wide groups of crustaceans, such as ''zoea'' and ''nauplius''. Other terms described forms which are only found in particular groups, such as the ''glaucothoe'' of hermit crabs, or the ''phyllosoma'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
