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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] |
Triops Australiensis Belly
''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] |
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] |
Lepidurus Apus
''Lepidurus apus'', commonly known as a tadpole shrimp, is a notostracan in the family Triopsidae, one of a lineage of shrimp-like crustaceans that have had a similar form since the Triassic period and are considered living fossils. This species is cosmopolitan, inhabiting temporary freshwater ponds over much of the world, and the most widespread of the tadpole shrimps. Like other notostracans, ''L. apus'' has a broad carapace, long segmented abdomen, and large numbers of paddle-like legs. It reproduces by a mixture of sexual reproduction and self-fertilisation of females. Description ''Lepidurus apus'' grows to in length. Its long abdomen is divided into about 30 segment-like rings, with two long caudal rami or "tails" attached behind the last ring. Between the tails is a projection which distinguishes ''Lepidurus'' from ''Triops'', the other notostracan genus. Its carapace is flat with an average length of , and is attached only at the front, covering up to two thirds of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triops Australiensis
''Triops australiensis'', sometimes referred to as a shield shrimp, is an Australian species of the tadpole shrimp '' Triops''. Distribution ''Triops australiensis'' has a wide distribution across Australia, excluding the northernmost parts of Western Australia, and Queensland. It is also absent from Tasmania in the south, where it is replaced by ''Lepidurus apus''. The two species can be distinguished by the presence of a supra-anal plate between the caudal rami at the end of the abdomen in ''L. apus'', which is lacking in ''T. australiensis''. Biology ''T. australiensis'' inhabits temporary pools of water in the arid regions of the Australian outback. When desiccated pools fill with water, the resting eggs hatch into nauplii, and rapidly develop to adulthood. Reproduction succeeds within a few weeks of hatching. Adults achieve a maximum size of around , which is considered large for a tadpole shrimp. Water chemistry ''Triops australiensis'' can tolerate a pH of 7–9, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepidurus
''Lepidurus'' is a genus of small crustaceans in the order Notostraca (tadpole shrimp). It is the larger of the two extant genera of the tadpole shrimps, the other being ''Triops''. They are commonly found in vernal pools and survive dry periods with the help of long lasting resting eggs. The genus contains the following species: *''Lepidurus apus'' (Linnaeus, 1758) *''Lepidurus arcticus'' (Pallas, 1793) *''Lepidurus batesoni'' Longhurst, 1955 *''Lepidurus bilobatus'' Packard, 1883 *''Lepidurus couesii'' Packard, 1875 *''Lepidurus cryptus'' D. C. Rogers, 2001 *''Lepidurus lemmoni'' Holmes, 1894 *''Lepidurus mongolicus'' Vekhoff, 1992 *''Lepidurus packardi ''Lepidurus packardi'', known by the common name vernal pool tadpole shrimp, is a rare species of tadpole shrimp (Notostraca). Distribution The freshwater crustacean is endemic to California, where it lives in the endangered vernal pool type of ...'' Simon, 1886 References External links * Notostraca Branchiopoda ... [...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] |
Temporary Pool
Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe development of natal amphibian and insect species unable to withstand competition or predation by fish. Certain tropical fish lineages (such as killifishes) have however adapted to this habitat specifically. Vernal pools are a type of wetland. They can be surrounded by many communities/species including deciduous forest, grassland, lodgepole pine forest, blue oak woodland, sagebrush steppe, succulent coastal scrub and prairie. These pools are characteristic of Mediterranean climates, but occur in many other ecosystems. Generation and annual development During most years, a vernal pool basin will experience inundation from rain/precipitation, followed by desiccation from evapotranspiration. These conditions are commonly associated with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod Leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plural ''coxae''), ''trochanter'', ''femur'' (plural ''femora''), ''tibia'' (plural ''tibiae''), ''tarsus'' (plural ''tarsi''), ''ischium'' (plural ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (plural ''patellae''). Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a ''Hox''-gene, could result in parallel gains of leg segments. In arthropods, each of the leg segments ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segmentation (biology)
Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, and Annelida. These three groups form segments by using a "growth zone" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this patterning. Even within these groups, different organisms have different mechanisms for segmenting the body. Segmentation of the body plan is important for allowing free movement and development of certain body parts. It also allows for regeneration in specific individuals. Definition Segmentation is a difficult process to satisfactorily define. Many taxa (for example the molluscs) have some form of serial repetition in their units but are not conventionally thought of as segmented. Segmented animals are tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the creature's body, each of which is in turn composed of multiple segments. The human thorax includes the thoracic cavity and the thoracic wall. It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures. Many diseases may affect the chest, and one of the most common symptoms is chest pain. Etymology The word thorax comes from the Greek θώραξ ''thorax'' "breastplate, cuirass, corslet" via la, thorax. Plural: ''thoraces'' or ''thoraxes''. Human thorax Structure In humans and other hominids, the thorax is the chest region of the body between the neck and the abdomen, along with its internal organs and other contents. It is mostly protected and supported by the rib cage, spi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing house specializing in monographs and scholarly journals. Most are nonprofit organizations and an integral component of a large research university. They publish work that has been reviewed by schola ... in the world. It is also the King's Printer. Cambridge University Press is a department of the University of Cambridge and is both an academic and educational publisher. It became part of Cambridge University Press & Assessment, following a merger with Cambridge Assessment in 2021. With a global sales presence, publishing hubs, and offices in more than 40 Country, countries, it publishes over 50,000 titles by authors from over 100 countries. Its publishing includes more than 380 academic journals, monographs, reference works, school and uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Wiley And Sons
John Wiley & Sons, Inc., commonly known as Wiley (), is an American multinational publishing company founded in 1807 that focuses on academic publishing and instructional materials. The company produces books, journals, and encyclopedias, in print and electronically, as well as online products and services, training materials, and educational materials for undergraduate, graduate, and continuing education students. History The company was established in 1807 when Charles Wiley opened a print shop in Manhattan. The company was the publisher of 19th century American literary figures like James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe, as well as of legal, religious, and other non-fiction titles. The firm took its current name in 1865. Wiley later shifted its focus to scientific, technical, and engineering subject areas, abandoning its literary interests. Wiley's son John (born in Flatbush, New York, October 4, 1808; died in East Orange, New Jer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
