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Pycnogonid
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] |
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] |
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] |
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] |
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] |
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] |
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] |
Muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle tissue, and are often known as muscle fibers. The muscle tissue of a skeletal muscle is striated – having a striped appearance due to the arrangement of the sarcomeres. Skeletal muscles are voluntary muscles under the control of the somatic nervous system. The other types of muscle are cardiac muscle which is also striated and smooth muscle which is non-striated; both of these types of muscle tissue are classified as involuntary, or, under the control of the autonomic nervous system. A skeletal muscle contains multiple fascicles – bundles of muscle fibers. Each individual fiber, and each muscle is surrounded by a type of connective tissue layer of fascia. Muscle fibers are formed from the fusion of developmental myoblasts in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diverticulum (mollusc)
As applied to mollusks, the New Latin term diverticulum is an anatomical feature. The term is most often encountered in the plural form as "diverticula", "hepatic diverticula", or "digestive diverticula", which are anatomical terms for organs which are visible from the outside of the body in a clade of sea slugs known as aeolid nudibranchs, marine opisthobranch gastropod molluscs. The term is also applied to mollusk anatomy in other contexts: land slugs such as ''Lehmannia marginata'' have a caecal diverticuluand there is also a diverticulum in the stomach of certain Bivalviabr> Description and functions In the Aeolidida Individual animals within the nudibranch clade Aeolidida have an array of long protruding structures called cerata on their dorsal surface. Located within the cerata of these nudibranchs are hepatic diverticula, which are an outgrowth of the digestive gland or hepatopancreas of the animal. The cerata are translucent, and thus the contents of the diverticula are e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate subphylum Vertebrata. Familiar examples of invertebrates include arthropods, mollusks, annelids, echinoderms and cnidarians. The majority of animal species are invertebrates; one estimate puts the figure at 97%. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata. Invertebrates vary widely in size, from 50 μm (0.002 in) rotifers to the 9–10 m (30–33 ft) colossal squid. Some so-called invertebrates, such as the Tunicata and Cephalochordata, are more closely related to vertebrates than to other invertebrates. This makes the invertebrates paraphyletic, so the term has little meaning in taxonomy. Etymology The word "invertebrate" comes from the Latin word ''vertebra'', whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
