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Pycnogonida
Sea spiders are marine arthropods of the order Pantopoda ( ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (; named after ''Pycnogonum'', the type genus; with the suffix '). They are cosmopolitan, found in oceans around the world. The over 1,300 known species have legs ranging from to over . Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters. Although "sea spiders" are not true spiders, or even arachnids, their traditional classification as chelicerates places them closer to true spiders than to other well-known arthropod groups, such as insects or crustaceans. This is in dispute, however, as genetic evidence suggests they may be the sister group to all other living arthropods. Description Sea spiders have long legs in contrast to a small body size. The number of walking legs is usually eight (four pairs), but the family Pycnogonidae hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pycnogonida Nymphon S Sars
Sea spiders are marine arthropods of the order Pantopoda ( ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (; named after '' Pycnogonum'', the type genus; with the suffix '). They are cosmopolitan, found in oceans around the world. The over 1,300 known species have legs ranging from to over . Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters. Although "sea spiders" are not true spiders, or even arachnids, their traditional classification as chelicerates places them closer to true spiders than to other well-known arthropod groups, such as insects or crustaceans. This is in dispute, however, as genetic evidence suggests they may be the sister group to all other living arthropods. Description Sea spiders have long legs in contrast to a small body size. The number of walking legs is usually eight (four pairs), but the family Pycnogonidae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Spider
Sea spiders are marine arthropods of the order Pantopoda ( ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (; named after ''Pycnogonum'', the type genus; with the suffix '). They are cosmopolitan, found in oceans around the world. The over 1,300 known species have legs ranging from to over . Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters. Although "sea spiders" are not true spiders, or even arachnids, their traditional classification as chelicerates places them closer to true spiders than to other well-known arthropod groups, such as insects or crustaceans. This is in dispute, however, as genetic evidence suggests they may be the sister group to all other living arthropods. Description Sea spiders have long legs in contrast to a small body size. The number of walking legs is usually eight (four pairs), but the family Pycnogonidae hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pycnogonidae
Pycnogonidae is a family of sea spiders. Characteristics Most sea spiders in the class Pycnogonida have appendages on the anterior end of the body called chelifores which are used for gathering food and palps which bear sensory organs. Members of the family Pycnogonidae have neither of these, instead using their proboscis to suck juices from their prey. On the first segment of the trunk of male family members there are ovigerous legs on which the larvae are carried. The females do not have these appendages. Like most sea spiders, all species in this family have four pairs of legs, except for three species (''Pentapycnon bouvieri'', ''P. charcoti'', and ''P. geayi'') with five pairs. Genera The World Register of Marine Species lists the following genera: *'' Pentapycnon'' Bouvier, 1910 *''Pycnogonum ''Pycnogonum'' is a genus of sea spiders in the family Pycnogonidae. It is the type genus of the family. Etymology The generic name literally means “dense knees”. ''Pycnogo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelicerates
The subphylum Chelicerata (from New Latin, , ) constitutes one of the major subdivisions of the phylum Arthropoda. It contains the sea spiders, horseshoe crabs, and arachnids (including harvestmen, scorpions, spiders, solifuges, ticks, and mites, among many others), as well as a number of extinct lineages, such as the eurypterids (sea scorpions) and chasmataspidids. The Chelicerata originated as marine animals in the Middle Cambrian period; the first confirmed chelicerate fossils, belonging to ''Sanctacaris'', date from 508 million years ago. The surviving marine species include the four species of xiphosurans (horseshoe crabs), and possibly the 1,300 species of pycnogonids (sea spiders), if the latter are indeed chelicerates. On the other hand, there are over 77,000 well-identified species of air-breathing chelicerates, and there may be about 500,000 unidentified species. Like all arthropods, chelicerates have segmented bodies with jointed limbs, all covered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pycnogonum
''Pycnogonum'' is a genus of sea spiders in the family Pycnogonidae. It is the type genus of the family. Etymology The generic name literally means “dense knees”. ''Pycnogonum'' combines the prefix ' (from ‘dense’ in Greek) with the Greek word for "knee": (). Characteristics Members of the genus ''Pycnogonum'' have squarish bodies with a tough integument and a few hairs. The cephalon (the anterior end of the body which is fused with the first segment of the trunk) has a long smooth proboscis and a low tubercle on which the eyes are set. There are no chelicerae or palps and these sea spiders use their proboscis to suck juices from their prey. On the first segment of the trunk of males there are small ovigerous legs with nine segments. The larvae are carried around by the males on these appendages. The four pairs of ambulatory legs are short but strong, with well-developed terminal claws. The genital openings are on the second segment of the posterior pair of legs. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arthropod cuticle, cuticle made of chitin, often Mineralization (biology), 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 exoskeleton, 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 Organ (anatomy), organs; it has an open circulatory system. Like their exteriors, the internal or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colossendeidae
Colossendeidae is a family of sea spider (class Pycnogonida). Like most sea spiders, all species in this family have four pairs of legs, except for three species (''Decolopoda australis'', ''D. qasimi'', and ''Pentacolossendeis reticulata'') with five pairs and one (''Dodecolopoda mawsoni'') with six pairs. Taxonomy * '' Colossendeis'' Jarzinsky, 1870 (67 species) ** '' Colossendeis acuta'' Stiboy-Risch, 1993 ** '' Colossendeis adelpha'' Child, 1998 ** '' Colossendeis angusta'' Sars, 1877 ** '' Colossendeis aperta'' Turpaeva, 2005 ** '' Colossendeis arcuata'' A. Milne-Edwards, 1885 ** '' Colossendeis australis'' Hodgson, 1907 ** '' Colossendeis avida'' Pushkin, 1970 ** '' Colossendeis belekurovi'' Pushkin, 1993 ** '' Colossendeis bicincta'' Schimkewitsch, 1893 ** '' Colossendeis brevirostris'' Child, 1995 ** '' Colossendeis bruuni'' Fage, 1956 ** '' Colossendeis clavata'' Meinert, 1899 ** '' Colossendeis colossea'' Wilson, 1881 ** '' Colossendeis concedis'' Child, 1995 ** '' Colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arachnid
Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroons. Almost all adult arachnids have eight legs, although the front pair of legs in some species has converted to a sensory function, while in other species, different appendages can grow large enough to take on the appearance of extra pairs of legs. The term is derived from the Greek word (''aráchnē'', 'spider'), from the myth of the hubristic human weaver Arachne, who was turned into a spider. Almost all extant arachnids are terrestrial, living mainly on land. However, some inhabit freshwater environments and, with the exception of the pelagic zone, marine environments as well. They comprise over 100,000 named species, of which 47,000 are species of spiders. Morphology Almost all adult arachnids have eight legs, unlike adult inse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep-sea Gigantism
In zoology, deep-sea gigantism or abyssal gigantism is the tendency for species of invertebrates and other deep-sea dwelling animals to be larger than their shallower-water relatives across a large taxonomic range. Proposed explanations for this type of gigantism include colder temperature, food scarcity, reduced predation pressure and increased dissolved oxygen concentrations in the deep sea. The inaccessibility of abyssal habitats has hindered the study of this topic. Taxonomic range In marine crustaceans, the trend of increasing size with depth has been observed in mysids, euphausiids, decapods, isopods and amphipods. Non-arthropods in which deep-sea gigantism has been observed are cephalopods, cnidarians, and eels from the order Anguilliformes. Examples of deep-sea gigantism include the big red jellyfish, the giant isopod, giant ostracod, the giant sea spider, the giant amphipod, the Japanese spider crab, the giant oarfish, the deepwater stingray, the seven-arm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nymphonidae
Nymphonidae is a family of sea spiders which has representatives in all the oceans. This family contains some 250 species, most of which are found in the genus ''Nymphon''. Nymphonid bodies are between 1 and 15 mm long, the extent between the points of the legs reaching 150 mm. Most species are predators of hydroids. Like most sea spiders, all species in this family have four pairs of legs, except for ''Pentanymphon antarcticum'', which has five pairs, and ''Sexanymphon mirabilis'', which has six pairs. Taxonomy Seven genera are currently recognized:Bamber, R.N., El Nagar, A. & Staples, D. (Eds) (2014). Pycnobase: World Pycnogonida Database. Accessed at http://www.marinespecies.org/pycnobase on 2014-10-30 * '' Boreonymphon'' Sars, 1888 (4 species) * '' Bradypallene'' Kim & Hong, 1987 (1 species) * '' Heteronymphon'' Gordon, 1932 (8 species) * '' Neonymphon'' Stock, 1955 (1 species) * ''Nymphon ''Nymphon'' is a genus of sea spiders in the family Nymphonidae. The speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. , 50,356 spider species in 132 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel, however, as there is currently neither paleontological nor embryological evidence that spiders ever had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre André Latreille
Pierre André Latreille (; 29 November 1762 – 6 February 1833) was a French zoologist, specialising in arthropods. Having trained as a Roman Catholic priest before the French Revolution, Latreille was imprisoned, and only regained his freedom after recognising a rare beetle species he found in the prison, ''Necrobia ruficollis''. He published his first important work in 1796 (), and was eventually employed by the . His foresighted work on arthropod systematics and taxonomy gained him respect and accolades, including being asked to write the volume on arthropods for George Cuvier's monumental work, , the only part not by Cuvier himself. Latreille was considered the foremost entomologist of his time, and was described by one of his pupils as "the prince of entomologists". Biography Early life Pierre André Latreille was born on 29 November 1762 in the town of Brive, then in the province of Limousin, as the illegitimate child of Jean Joseph Sahuguet d'Amarzit, général ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
