|
Tetrapulmonate
Tetrapulmonata is a non-ranked supra-ordinal clade of arachnids. It is composed of the extant orders Uropygi (whip scorpions), Schizomida (short-tailed whip scorpions), Amblypygi (tail-less whip scorpions) and Araneae (spiders). It is the only supra-ordinal group of arachnids that is strongly supported in molecular phylogenetic studies. Two extinct orders are also placed in this clade, Haptopoda and Uraraneida. In 2016, a newly described fossil arachnid, ''Idmonarachne'', was also included in the Tetrapulmonata; it has not been assigned to an order. Etymology It receives its name from the presence of paired book lungs occupying the second and third opisthosomal segments, although the posterior pair is absent in Schizomida and most araneomorph spiders. Previous synonyms of this lineage are rejected; "Caulogastra Pocock, 1893" refers to pedicel, which is symplesiomorphic for the lineage and convergent with Solifugae, and "Arachnidea Van der Hammen, 1977" is easily confused wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonotarbid
The Order (biology), order Trigonotarbida is a group of extinct arachnids whose fossil record extends from the late Silurian to the early Permian (Pridoli epoch, Pridoli to Sakmarian).Dunlop, J. A., Penney, D. & Jekel, D. 2020A summary list of fossil spiders and their relatives In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch , version 20.5 These animals are known from several localities in Europe and North America, as well as a single record from Argentina. Trigonotarbids can be envisaged as spider-like arachnids, but without silk-producing spinnerets. They ranged in size from a few millimetres to a few centimetres in body length and had segmented abdomens (opisthosoma), with the dorsal exoskeleton (Tergum, tergites) across the backs of the animals' abdomens, which were characteristically divided into three or five separate plates. Probably living as predators on other arthropods, some later trigonotarbid species were quite heavily armoured and pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Idmonarachne
''Idmonarachne'' is an extinct genus of arachnids, containing one species, ''Idmonarachne brasieri''. It is related to uraraneids and spiders. Fossil A fossil assigned to this genus was found at Montceau-les-Mines, France, in ironstone concretion deposits of Late Carboniferous ( Stephanian) age, about 305–299 million years old. Montceau fossils are generally preserved in such a way that fine details can be observed and three-dimensional analysis is possible. In the case of ''Idmonarachne'', computerized tomography was used to construct a "virtual fossil". Description The total body length of the fossil is around 10.5 mm, with the preserved part of the carapace of the cephalothorax about 5 mm long and the opisthosoma (abdomen) about 6 mm long. The eight walking legs are more-or-less uniform in appearance, with the fourth leg longest at about 8.5 mm and the first shortest at about 6.5 mm. The legs terminate in at least two claws. The two pedipalps are sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uraraneida
Uraraneida is an extinct order of Paleozoic arachnids related to modern Spider, spiders. Two genera of fossils have been definitively placed in this order: ''Attercopus'' from the Devonian of United States and ''Permarachne'' from the Permian of Russia. Like spiders, they are known to have produced silk, but lack the characteristic Spinneret, spinnerets of modern spiders, and retain elongate Telson, telsons. Characteristics The first fossil now placed in the order was found in Gilboa, New York. In 1987, it was initially tentatively placed in the extinct order Trigonotarbida and named ''Gelasinotarbus''? ''fimbriunguis''. Later, partly on the basis of a supposed spinneret (spider), spinneret, it was identified as a spider and named ''Attercopus fimbriunguis''. Further specimens of this species were found, and when examined in detail, along with those assigned to the genus ''Permarachne'', features inconsistent with their placement as spiders were revealed. Silk producing spigots ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Book Lung
A book lung is a type of respiration organ used for atmospheric gas-exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open, ventral-abdominal, air-filled cavity (atrium) and connects with its surroundings through a small opening for the purpose of respiration. Structure and function Book lungs are not related to the lungs of modern land-dwelling vertebrates. Their name instead describes their structure and purpose as a case of convergent evolution. Stacks of alternating air pockets and tissue filled with hemolymph give them an appearance similar to a "folded" book. Their number varies from just one pair in most spiders to four pairs in scorpions. The unfolded "pages" (plates) of the book lung are filled with hemolymph. The folds maximize the surface exposed to air, and thereby maximize the amount of gas exchanged with the environment. In most species, no motion of the plates is needed to facilitate this ki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extant Taxon
Neontology is a part of biology that, in contrast to paleontology, studies and deals with living (or, more generally, '' recent'') organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct. For example: * The Indian elephant (''Elephas maximus'') is an extant species, and the woolly mammoth (''Mammuthus primigenius'') is an extinct species. * The moose (''Alces alces'') is an extant species, and the Irish elk (''Megaloceros giganteus'') is an extinct species. * In the group of molluscs known as the cephalopods, there were approximately 600 extant species and 7,500 extinct species. A taxon can be classified as extinct if it is broadly agreed or certified that no members of the group are still alive. Conversely, an extinct taxon can be reclassified as extant if there are new discoveries of living species (" Lazarus species"), or if previously known extant species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arachnid
Arachnids are arthropods in the Class (biology), class Arachnida () of the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, opiliones, harvestmen, Solifugae, camel spiders, Amblypygi, whip spiders and Uropygi, vinegaroons. Adult arachnids have eight Arthropod leg, legs attached to the cephalothorax. In some species the frontmost pair of legs has converted to a sensory function, while in others, different appendages can grow large enough to take on the appearance of extra pairs of legs. Almost all Extant taxon, extant arachnids are terrestrial animal, 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 110,000 named species, of which 51,000 are species of spiders. The term is derived from the Ancient Greek, Greek word (''aráchnē'', 'spider'), from the myth of the hubristic human weaver Arachne, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solifugae
Solifugae is an Order (biology), order of Arachnid, arachnids known variously as solifuges, sun spiders, camel spiders, and wind scorpions. The order includes more than 1,000 described species in about 147 genus, genera. Despite the common names, they are neither true spiders (order Araneae), nor true scorpions (order Scorpiones). Most species of solifuges live in dry climates and feed opportunistically on ground-dwelling arthropods and other small animals. The largest species grow to a length of , including legs. A number of urban legends exaggerate the size and speed of solifuges, and their potential danger to humans, which is negligible. Etymology The order's name is derived from the Latin ''sol'' meaning "sun" and ''fugere'' meaning "to flee". Put together, it means "those that flee from the sun". These animals have a number of common names, including sun spiders, wind scorpions, wind spiders, red romans, and camel spiders. In Afrikaans, they are known as ''haarskeerders'' ("h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is Cladogram#Homoplasies, homoplasy. The recurrent evolution of flight is a classic example, as flying pterygota, insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas ''homology (biology), homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different trai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symplesiomorphy
In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy all mean a trait shared between species because they share an ancestral species. Apomorphic and synapomorphic characteristics convey much information about evolutionary clades and can be used to define taxa. However, plesiomorphic and symplesiomorphic characteristics cannot. The term ''symplesiomorphy'' was introduced in 1950 by German entomologist Willi Hennig. Examples A backbone is a plesiomorphic trait shared by birds and mammals, and does not help in placing an animal in one or the other of these two clades. Birds and mammals share this trait because both clades are descended from the same far distant ancestor. Other clades, e.g. snakes, lizards, turtles, fish, frogs, all have backbones and none are either birds n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedicel (spider)
The anatomy of spiders includes many characteristics shared with other arachnids. These characteristics include bodies divided into two tagmata (sections or segments), eight jointed legs, no wings or antennae, the presence of chelicerae and pedipalps, simple eyes, and an exoskeleton, which is periodically shed. Spiders also have several adaptations that distinguish them from other arachnids. All spiders are capable of producing silk of various types, which many species use to build webs to ensnare prey. Most spiders possess venom, which is injected into prey (or defensively, when the spider feels threatened) through the fangs of the chelicerae. Male spiders have specialized pedipalps that are used to transfer sperm to the female during mating. Many species of spiders exhibit a great deal of sexual dimorphism. External anatomy Spiders, unlike insects, have only two main body parts ( tagmata) instead of three: a fused head and thorax (called a cephalothorax or prosoma) and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synonym (taxonomy)
In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The Botanical nomenclature, botanical and Zoological nomenclature, zoological codes of nomenclature treat the concept of synonymy differently. * In nomenclature, botanical nomenclature, a synonym is a Binomial nomenclature, scientific name that applies to a taxon that now goes by a different scientific name. For example, Carl Linnaeus, Linnaeus was the first to give a scientific name (under the currently used system of scientific nomenclature) to the Norway spruce, which he called ''Pinus abies''. This name is no longer in use, so it is now a synonym of the current scientific name, ''Picea abies''. * In zoology, moving a species from one genus to another results in a different Binomial nomenclature, binomen, but the name is considered an alternative combination rather than a synonym. The concept of synonymy in zoology is reserved f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araneomorphae
The Araneomorphae (also called the Labidognatha or "true spiders") are an infraorder of spiders. They are distinguishable by chelicerae (fangs) that point diagonally forward and cross in a pinching action, in contrast to the Mygalomorphae (tarantulas and their close kin), where they point straight down. Araneomorphs comprise the vast majority (about 93%) of living spiders. Distinguishing characteristics Most spider species are Araneomorphae, which have chelicerae, fangs that face towards each other, increasing the orientations that they can employ during prey-capture. They have fewer book lungs (when present) – usually one pair – and the females typically live one year. The Mygalomorphae have chelicerae, fangs that face towards the ground, and which are parallel to the long axis of the spider's body, thus they have only one orientation they can employ during prey capture. They have two pairs of book lungs, and the females often live many years. Image:Cheiracanthium pun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
