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Myriapod Anatomy
Myriapods () are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial. The fossil record of myriapods reaches back into the late Silurian, although molecular evidence suggests a diversification in the Cambrian Period, and Cambrian fossils exist which resemble myriapods. The oldest unequivocal myriapod fossil is of the millipede ''Pneumodesmus newmani'', from the late Silurian (428 million years ago). ''P. newmani'' is also important as the earliest known terrestrial animal. The phylogenetic classification of myriapods is still debated. The scientific study of myriapods is myriapodology, and those who study myriapods are myriapodologists. Anatomy Myriapods have a single pair of antennae and, in most cases, simple eyes. Exceptions are the two classes symphylans and pauropods, and the millipede order Polydesmida and the centipede order Geophilomorpha, which are all eyeless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chilopoda
Centipedes (from New Latin , "hundred", and Latin , " foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', lip, and New Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, an arthropod group which includes millipedes and other multi-legged animals. Centipedes are elongated segmented (metameric) creatures with one pair of legs per body segment. All centipedes are venomous and can inflict painful bites, injecting their venom through pincer-like appendages known as forcipules. Despite the name, centipedes can have a varying number of legs, ranging from 30 to 382. Centipedes always have an odd number of pairs of legs; no centipede has exactly 100. Like spiders and scorpions, centipedes are predominantly carnivorous. Their size ranges from a few millimetres in the smaller lithobiomorphs and geophilomorphs to about in the largest scolopendromorphs. Centipedes can be found in a wide variety of environments. They ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pneumodesmus Newmani
''Pneumodesmus newmani'' is a species of myriapod that lived in the Paleozoic. Its exact age is uncertain; it was originally interpreted as living , in the Late Silurian; however, subsequent research dates it to around 414 million years old, in the Early Devonian (Lochkovian). It is one of the first myriapods, and among the oldest creatures to have lived on land. It was discovered in 2004, and is known from a single specimen from Stonehaven, Aberdeenshire, Scotland. Discovery and naming The fossil of ''P. newmani'' was found by Mike Newman, a bus driver and amateur palaeontologist from Aberdeen, in a layer of sandstone rocks on the foreshore of Cowie, near Stonehaven. The species was later given the specific epithet "''newmani''" in honour of Newman. The holotype is kept in National Museum of Scotland, Edinburgh. The genus name is said to derived from the Greek ''pneumato'', meaning "air" or "breath", in reference to the inferred air-breathing habit. The proper word in ancient G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandible (arthropod)
250px, The mandibles of a bull ant The mandible (from la, mandibula or mandĭbŭ-lum, a jaw) of an arthropod is a pair of mouthparts used either for biting or cutting and holding food. Mandibles are often simply called jaws. Mandibles are present in the extant subphyla Myriapoda (millipedes and others), Crustacea and Hexapoda (insects etc.). These groups make up the clade Mandibulata, which is currently believed to be the sister group to the rest of arthropods, the clade Arachnomorpha (Chelicerata and Trilobita). Unlike the chelicerae of arachnids, mandibles can often be used to chew food. Mandibulates also differ by having antennae, and also by having three distinct body regions: head, thorax and abdomen. (The cephalothorax (or prosoma) of chelicerates is a fusion of head and thorax.) Insects Insect mandibles are as diverse in form as their food. For instance, grasshoppers and many other plant-eating insects have sharp-edged mandibles that move side to side. Most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla (arthropod)
In arthropods, the maxillae (singular maxilla) are paired structures present on the head as mouthparts in members of the clade Mandibulata, used for tasting and manipulating food. Embryologically, the maxillae are derived from the 4th and 5th segment of the head and the maxillary palps; segmented appendages extending from the base of the maxilla represent the former leg of those respective segments. In most cases, two pairs of maxillae are present and in different arthropod groups the two pairs of maxillae have been variously modified. In crustaceans, the first pair are called maxillulae (singular maxillula). Modified coxae at the base of the pedipalps in spiders are also called "maxillae", although they are not homologous with mandibulate maxillae. Myriapoda Millipedes In millipedes, the second maxillae have been lost, reducing the mouthparts to only the first maxillae which have fused together to form a gnathochilarium, acting as a lower lip to the buccal cavity and the mand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod Mouthparts
The mouthparts of arthropods have evolved into a number of forms, each adapted to a different style or mode of feeding. Most mouthparts represent modified, paired appendages, which in ancestral forms would have appeared more like legs than mouthparts. In general, arthropods have mouthparts for cutting, chewing, piercing, sucking, shredding, siphoning, and filtering. This article outlines the basic elements of four arthropod groups: insects, myriapods, crustaceans and chelicerates. Insects are used as the model, with the novel mouthparts of the other groups introduced in turn. Insects are not, however, the ancestral form of the other arthropods discussed here. Insects Insect mouthparts exhibit a range of forms. The earliest insects had chewing mouthparts. Specialisation includes mouthparts modified for siphoning, piercing, sucking and sponging. These modifications have evolved a number of times. For example, mosquitoes (which are flies) and aphids (which are bugs) both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Eye
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distinguish brightness and color. The image perceived by this arthropod eye is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions. Compared with single-aperture eyes, compound eyes have poor image resolution; however, they possess a very large view angle and the ability to detect fast movement and, in some cases, the polarization of light. Because a compound eye is made up of a collection of ommatidia, each with its own lens, light will enter each ommatidium instead of using a single entrance point. The individual light receptors behind each lens are then turned on and off due to a series of changes in the light intensity during movement or when an object in moving, creating a flic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scutigera
''Scutigera'' is a centipede genus in the scutigeromorph (house centipede) family Scutigeridae, a group of centipedes with long limbs and true compound eyes (which were once thought to be secondary, re-evolved "pseudofacetted eyes"). It compose of more than 30 species, including the most common and well-studied ''Scutigera coleoptrata.'' Species Extant species * '' Scutigera aethiopica'' * ''Scutigera argentina'' * '' Scutigera asiatica'' * '' Scutigera buda'' * '' Scutigera carrizala'' * ''Scutigera chichivaca'' * ''Scutigera coleoptrata'' * '' Scutigera complanata'' * '' Scutigera dubia'' * ''Scutigera fissiloba'' * '' Scutigera flavistoma'' * '' Scutigera hispida'' * '' Scutigera linceci'' * ''Scutigera longitarsis'' * ''Scutigera marmorea'' * ''Scutigera melanostoma'' * ''Scutigera nossibei'' * ''Scutigera oweni'' * ''Scutigera oxypyga'' * ''Scutigera parcespinosa'' * ''Scutigera planiceps'' * ''Scutigera poicila'' * ''Scutigera rubrilineata'' * ''Scutigera sanguinea'' * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orders Of Centipedes
The centipedes or Chilopoda are divided into the following orders. Scutigeromorpha The Scutigeromorpha are anamorphic, reaching 15 leg-bearing segments in length. Also known as house centipedes, they are very fast creatures, and able to withstand falling at great speed: they reach up to 15 body lengths per second when dropped, surviving the fall. They are the only centipede group to retain their original compound eyes, within which a crystalline layer analogous to that seen in chelicerates and insects can be observed. They also bear long and multi-segmented antennae. Adaptation to a burrowing lifestyle has led to the degeneration of compound eyes in other orders; this feature is of great use in phylogenetic analysis. The group is the sole extant representative of the Notostigmophora, defined by having a single spiracle opening at the posterior of each dorsal plate. The more derived groups bear a plurality of spiracular openings on their sides, and are termed the Pleurostigmopho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polydesmida
Polydesmida (from the Greek language, Greek ''poly'' "many" and ''desmos'' "bond") is the largest order (biology), order of millipedes, containing approximately 3,500 species, including all the millipedes reported to produce hydrogen cyanide (HCN). Description Members of the order Polydesmida are also known as "flat-backed millipedes", because on most species, each body segment has wide lateral keels known as paranota. These keels are produced by the posterior half (metazonite) of each body ring behind the collum (millipedes), collum. Polydesmids have no eyes, and vary in length from . Many of the larger species show bright coloration patterns which warn predators of their toxic secretions. Adults usually have 20 segments, counting the collum as the first ring and the telson as the last ring. juvenile (organism), Juveniles have from 7 to 19 rings. In species with the usual 20 segments, adult females have 31 pairs of legs, but in adult males, the eighth leg pair (the first leg pai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (biology)
Antennae ( antenna), sometimes referred to as "feelers", are paired appendages used for sensing in arthropods. Antennae are connected to the first one or two segments of the arthropod head. They vary widely in form but are always made of one or more jointed segments. While they are typically sensory organs, the exact nature of what they sense and how they sense it is not the same in all groups. Functions may variously include sensing touch, air motion, heat, vibration (sound), and especially smell or taste. Antennae are sometimes modified for other purposes, such as mating, brooding, swimming, and even anchoring the arthropod to a substrate. Larval arthropods have antennae that differ from those of the adult. Many crustaceans, for example, have free-swimming larvae that use their antennae for swimming. Antennae can also locate other group members if the insect lives in a group, like the ant. The common ancestor of all arthropods likely had one pair of uniramous (unbranched ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Houghton Mifflin Harcourt
Houghton Mifflin Harcourt (; HMH) is an American publisher of textbooks, instructional technology materials, assessments, reference works, and fiction and non-fiction for both young readers and adults. The company is based in the Financial District, Boston, Boston Financial District. It was formerly known as Houghton Mifflin Company, but it changed its name following the 2007 acquisition of Harcourt (publisher), Harcourt Publishing. Prior to March 2010, it was a subsidiary of EMPG, Education Media and Publishing Group Limited, an Irish-owned holding company registered in the Cayman Islands and formerly known as Riverdeep. History Ticknor and Allen, 1832 In 1832, William Ticknor and John Allen purchased a bookselling business in Boston and began to involve themselves in publishing; James T. Fields joined as a partner in 1843. Fields and Ticknor gradually gathered an impressive list of writers, including Ralph Waldo Emerson, Nathaniel Hawthorne, and Henry David Thoreau. The d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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