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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 ... [...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 baro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Their blood is not totally contained in vessels; some circulates in an open cavity known as the haemocoel. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; In: potentially over 90% of the animal life forms on Earth are insects. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans, which recent research has indicated insects are nested within. Nearly all insects hatch f ... [...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 ... [...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 ar ... [...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 ''verteb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proboscis
A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elongated nose or snout. Etymology First attested in English in 1609 from Latin , the latinisation of the Ancient Greek (), which comes from () 'forth, forward, before' + (), 'to feed, to nourish'. The plural as derived from the Greek is , but in English the plural form ''proboscises'' occurs frequently. Invertebrates The most common usage is to refer to the tubular feeding and sucking organ of certain invertebrates such as insects (e.g., moths, butterflies, and mosquitoes), worms (including Acanthocephala, proboscis worms) and gastropod molluscs. Acanthocephala The Acanthocephala or thorny-headed worms, or spiny-headed worms are characterized by the presence of an eversible proboscis, armed with spines, which it uses to pierce a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, like in spinodal decomposition. The concept of diffusion is widely used in many fields, including physics ( particle diffusion), chemistry, biology, sociology, economics, and finance (diffusion of people, ideas, and price values). The central idea of diffusion, however, is common to all of these: a substance or collection undergoing diffusion spreads out from a point or location at which there is a higher concentration of that substance or collection. A gradient is the change in the value of a quantity, for example, concentration, pressure, or temperature with the change in another variable, usually distance. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Respiratory System
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs; in mammals and reptiles these are called alveoli, and in birds they are known as atria. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary ... [...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'' Fabricius, 1794 (> 250 species) * '' Pentanymphon'' Hodgson, 1904 (1 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] |
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”. ''Pycnog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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