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Crustaceans Of The Eastern Pacific Ocean
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 their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Podocopa
The Podocopa are a subclass of ostracods. Members of the subclass Podocopa can be differentiated from the other subclass of ostracods (Myodocopa) by the morphology of the second antenna: the Podocopa have a relatively long endopod, whereas the Myodocopa have a relatively long exopod. The seventh limb of the Podocopa has a variety of forms or is absent, but is never an annulated worm-like limb (as seen in some Myodocopa). Taxonomy The following orders and unplaced families are recognised in the subclass Podocopa: * Order Palaeocopida * Order Platycopida * Order Podocopida The Podocopida are an order of ostracods in the subclass Podocopa. It is the most diverse of the four orders of ostracods, and also has a rich fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trac ... * Unplaced families ** Family † Pachydomellidae Berdan & Sohn, 1961 ** Family † Rectellidae Neckaya, 1966 ** Family † Rectonariidae Gruendel, 1962 Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
