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Oligochaetes
Oligochaeta () is a subclass of animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadrile earthworms (some of which are semiaquatic or fully aquatic), and freshwater or semiterrestrial microdrile forms, including the tubificids, pot worms and ice worms ( Enchytraeidae), blackworms ( Lumbriculidae) and several interstitial marine worms. With around 10,000 known species, the Oligochaeta make up about half of the phylum Annelida. These worms usually have few setae (chaetae) or "bristles" on their outer body surfaces, and lack parapodia, unlike polychaeta. Diversity Oligochaetes are well-segmented worms and most have a spacious body cavity (coelom) used as a hydroskeleton. They range in length from less than up to in the 'giant' species such as the giant Gippsland earthworm (''Megascolides australis'') and the Mekong worm (''Amynthas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic, Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Worm
Ice worms (also written as ice-worms or iceworms) are enchytraeid annelids of the genus ''Mesenchytraeus''. The majority of the species in the genus are abundant in gravel beds or the banks of riverine habitats, but the best-known members of the genus are found in glacial ice. They include the only annelid worms known to spend their entire lives in glacial ice, and some of the few metazoans to complete their entire life cycle at conditions below . They were discovered in a wide range of environments, which include level snowfields, steep avalanche cones, crevasse walls, glacial rivers and pools, and hard glacier ice. These organisms are unique in that they can simply move between tightly packed ice crystals. They utilize setae, which are small bristles found on the outside of their bodies, to grip the ice and pull themselves along. The genus contains 77 species, including the North American glacier ice worm ('' Mesenchytraeus solifugus'') and the Yosemite snow worm ('' Mesenchy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megascolecidae
The Megascolecidae is a taxonomic family of earthworms which is native to Madagascar, Australia, New Zealand and both South East Asia and North America. All species of Megascolecidae belong to the Clitellata class. Megascolecidae are a large family of earthworms and they can grow up to 2 meters in length. The intercontinental distribution of Megascolecidae helps in favouring the Continental Drift theory.Reynolds, J.W. 1995. The distribution of earthworms (Annelida, Oligochaeta) in North America. Pp. 133- 153 In: Mishra, P.C., N. Behera, B.K. Senapati and B.C. Guru (eds.). Advances in Ecology and Environmental Sciences. New Delhi: Ashish Publishing House, 651 pp. The distinctive feature that differs Megascolecidae from other earthworm families is their large size in comparison with other earthworm families. They are an essential part of maintaining soil structure, minor carbon sequestration, and maintaining terrestrial ecosystem balance. Megascolecidae is one of many families Anne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumbricidae
The Lumbricidae are a family of earthworms. About 33 lumbricid species have become naturalized around the world, but the bulk of the species are in the Holarctic region: from Canada (e.g. ''Bimastos lawrenceae'' on Vancouver Island) and the United States (e.g. ''Eisenoides carolinensis'', ''Eisenoides lonnbergi'' and most ''Bimastos'' spp.) and throughout Eurasia to Japan (e.g. ''Eisenia japonica'', ''E. koreana'' and ''Helodrilus hachiojii''). An enigmatic species in Tasmania is ''Eophila eti''. Currently, 670 valid species and subspecies in about 42 genera are recognized. This family includes the majority of earthworm species well known to Europeans. Genera The family consists of the following genera: * ''Allolobophora'' Eisen, 1874 * '' Alpodinaridella'' Mršić, 1987 * ''Aporrectodea'' Orley, 1885 * ''Bimastos'' Moore, 1893 * '' Castellodrilus'' Qiu & Bouché, 1998 stat. nov. * '' Cataladrilus'' Qiu & Bouché, 1998 * '' Cernosvitovia'' Omodeo, 1956 * '' Creinella'' Mrši ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossoscolecidae
The Glossoscolecidae are a large family of earthworms (annelids) which has native representatives in South and Central America. The species '' Pontoscolex corethrurus'' has a circumtropical distribution. They are found mostly in forest, but one species of earthworms lives primarily in coastal beach sand. The earthworms in this family can reach up to 2 m in length. Selected genera * '' Andiorrhinus'' * ''Diaguita The Diaguita people are a group of South American indigenous people native to the Chilean Norte Chico and the Argentine Northwest. Western or Chilean Diaguitas lived mainly in the Transverse Valleys which incised in a semi-arid environment. E ...'' * '' Enantiodrilus'' * '' Eurydame'' * '' Fimoscolex'' * '' Glossodrilus'' * '' Glossoscolex'' * '' Holoscolex'' * '' Rhigiodrilus'' * '' Urochaeta'' * '' Pontoscolex'' References Haplotaxida Annelid families {{Annelid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mekong Worm
''Amynthas mekongianus'', the Mekong worm or Mekong giant earthworm, previously known as ''Megascolex mekongianus'', is a species of earthworm in the family Megascolecidae. It is native to the vicinity of the River Mekong in southeastern Asia and may have more than 500 segments and grow to a length of . Description The Mekong giant earthworm may grow to a length of up to . Compared to their great length, these worms are relatively slender. The type specimen was one metre long and wide at the broadest point (segment 5). It had 370 segments and was a greyish colour, rather paler on the ventral surface. The prostomium was poorly preserved. The second segment had 46 setae (bristles) in an incomplete ring with a gap on the ventral surface. Segments 3 to 25 bore about 100 setae each, arranged in a complete ring. The male pores were on segment 17, but this specimen was immature and lacked a clitellum. Distribution and habitat The type specimen was recorded as being from "Ban Leum on M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Gippsland Earthworm
The giant Gippsland earthworm, ''Megascolides australis'', is one of Australia's 1,000 native earthworm species. Description These giant earthworms average long and in diameter and can reach in length; however, their body is able to expand and contract making them appear much larger. On average they weigh about . They have a dark purple head and a blue-grey body, and about 300 to 400 body segments. Ecology They live in the subsoil of blue, grey or red clay soils along stream banks and some south- or west-facing hills of their remaining habitat which is in Gippsland in Victoria, Australia. These worms live in deep burrow systems and require water in their environment to respire. They have relatively long life spans for invertebrates and can take 5 years to reach maturity. They breed in the warmer months and produce egg capsules that are to in length which are laid in their burrows. When these worms hatch in 12 months they are around long at birth. Unlike most earthw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroskeleton
A hydrostatic skeleton, or hydroskeleton, is a flexible skeleton supported by fluid pressure. Hydrostatic skeletons are common among simple invertebrate organisms. While more advanced organisms can be considered hydrostatic, they are sometimes referred to as hydrostatic for their possession of a hydrostatic organ instead of a hydrostatic skeleton. A hydrostatic organ and a hydrostatic skeleton may have the same capabilities, but they are not the same. Hydrostatic organs are more common in advanced organisms, while hydrostatic skeletons are more common in primitive organisms. As its name suggests, containing hydro meaning "water", being hydrostatic means that the skeleton or organ is fluid-filled. As a skeletal structure, it possesses the ability to affect shape and movement, and involves two mechanical units: the muscle layers and the body wall. The muscular layers are longitudinal and circular, and part of the fluid-filled coelom within. Contractions of the circular muscles leng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Cavity
A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and the dorsal body cavity. In the dorsal body cavity the brain and spinal cord are located. The membranes that surround the central nervous system organs (the brain and the spinal cord, in the cranial and spinal cavities) are the three meninges. The differently lined spaces contain different types of fluid. In the meninges for example the fluid is cerebrospinal fluid; in the abdominal cavity the fluid contained in the peritoneum is a serous fluid. In amniotes and some invertebrates the peritoneum lines their largest body cavity called the coelom. Mammals Mammalian embryos develop two body cavities: the intraembryonic coelom and the extraembryonic coelom (or chorionic cavity). The intraembryonic coelom is lined by somatic and sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychaeta
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm (''Arenicola marina'') and the sandworm or clam worm ''Alitta''. Polychaetes as a class are robust and widespread, with species that live in the coldest ocean temperatures of the abyssal plain, to forms which tolerate the extremely high temperatures near hydrothermal vents. Polychaetes occur throughout the Earth's oceans at all depths, from forms that live as plankton near the surface, to a 2- to 3-cm specimen (still unclassified) observed by the robot ocean probe ''Nereus'' at the bottom of the Challenger Deep, the deepest known spot in the Earth's oceans. Only 168 species (less than 2% of all polychaetes) are known fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapodium
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed lateral outgrowths that bear the chaetae. In several groups of sea snails and sea slugs, 'parapodium' refers to lateral fleshy protrusions. __TOC__ Annelid parapodia Most species of polychaete annelids have paired, fleshy parapodia which are segmentally arranged along the body axis. Parapodia vary greatly in size and form, reflecting a variety of functions, such as gas exchange, anchorage, protection and locomotion. General description Parapodia in polychaetes can be uniramous (consisting of one lobe or ramus) but are usually biramous (two lobes or rami). In the latter case, the dorsal lobes are called notopodia and the ventral lobes neuropodia. Both neuropodia and notopodia may possess a bundle of chaetae (neurochaetae and notocha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seta
In biology, setae (singular seta ; from the Latin word for " bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. They help, for example, earthworms to attach to the surface and prevent backsliding during peristaltic motion. These hairs make it difficult to pull a worm straight from the ground. Setae in oligochaetes (a group including earthworms) are largely composed of chitin. They are classified according to the limb to which they are attached; for instance, notosetae are attached to notopodia; neurosetae to neuropodia. Crustaceans have mechano- and chemosensory setae. Setae are especially present on the mouthparts of crustaceans and can also be found on grooming limbs. In some cases, setae are modified into scale like structures. Setae on the legs of krill and other small crustaceans help them to gather phytoplankton. It captures them and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
