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Uraraneida
Uraraneida is an extinct order of arachnids, known from fossils of Middle Devonian, Permian and possibly Cretaceous age. 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. In 2018, a third genus ''Chimerarachne'', from the Cretaceous of Myanmar was proposed to belong to this group, but this placement is disputed. When the first fossils were found, they were identified as spiders, but now constitute the Uraraneida, a separate but closely related group. 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, it was identified as a spider and named ''Attercopus fimbriunguis''. Further specimens of this species were found, and when examined in detail, along with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araneida
Araneida is a subgroup of Tetrapulmonata. It was originally defined by Jörg Wunderlich in 2015 as a subgroup of Araneae, including all true spiders, with Wunderlich also including Uraraneida within Araneae., cited in Araneida was redefined by Wunderlich in 2019 to include all modern spiders (Araneae), as well as Chimerarachnida, but excluding Uraraneida. Chimerarachnida and Araneae both possess spinnerets A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and are ..., which are absent in Uraraneida. Uraraneida and Araneida are grouped together in the clade Serikodiastida.Wunderlich, J. 2019What is a spider?Beiträge zur Araneologie 12: 1–32. See also * Araneidae References Spiders Arthropod suborders {{spider-stub ... [...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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapulmonata
Tetrapulmonata is a non-ranked supra-ordinal clade of arachnids. It is composed of the extant orders Thelyphonida (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 co ... [...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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chimerarachne
''Chimerarachne'' is a genus of extinct arachnids, sometimes considered as spider itself,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 containing a single species ''Chimerarachne yingi''. Fossils of ''Chimerarachne'' were discovered in Burmese amber from Myanmar which dates to the mid-Cretaceous, about 100 million years ago. Its classification is disputed, either belonging to Uraraneida a group otherwise known from the Devonian to Permian, or a separate clade closer to spiders. Since the earliest spider fossils are from the Carboniferous, either answer results in an at least a 170 myr ghost lineage with no fossil record, making it a Lazarus taxon. The size of the animal is quite small, being only in body length, with the tail being about in length. These fossils resemble spiders in having two of their key defining features: spinne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attercopus
''Attercopus'' is an extinct genus of arachnids, containing one species ''Attercopus fimbriunguis'', known from flattened cuticle fossils from the Panther Mountain Formation in Upstate New York. It is placed in the extinct order Uraraneida, spider-like animals able to produce silk, but which lacked true spinnerets and retained a segmented abdomen bearing a flagellum-like tail resembling that of a whip scorpion. They are thought to be close to the origins of spiders. Its name is taken from the English dialect word ''attercop'' ("spider"), which came from '' ang, attorcoppa'' ("poison-head"), from '' ang, ator'' ("poison"), itself drawn from the Proto-Germanic ''*aitra-'' ("poisonous ulcer") and ''kopp-'' ("head"). An important Early Devonian (about ) fossil example from Gilboa, New York, was originally described as a member of the extinct order Trigonotarbida and named ''Gelasinotarbus? fimbriunguis''. It was later assigned to a new genus ''Attercopus'' and reinterpreted as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permarachne
''Permarachne'' is an extinct genus of arachnids containing the single species ''Permarachne novokshonovi'' from the Permian (Kungurian) of Russia, found in the Koshelevka Formation near the town of Suksun in Perm Krai. It is closely related to modern spiders but unlike them, it has a long thin tail, similar to its relative '' Attercopus'', it is known from the mostly complete holotype PIN 4909/12. It is about 1 cm in size. It initially was thought to be a spider, but is now thought to form a clade with at least its close relative ''Attercopus'', forming the grouping Uraraneida Uraraneida is an extinct order of arachnids, known from fossils of Middle Devonian, Permian and possibly Cretaceous age. Two genera of fossils have been definitively placed in this order: ''Attercopus'' from the Devonian of United States and '' .... References Permian arthropods Prehistoric arachnid genera {{permian-animal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Clade analysis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the ICS geologic timescale, the younger of two subperiods (or upper of two subsystems) of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-productive beds of this age are widespread. The division between Pennsylvanian and Mississippian comes from North American stratigraphy. In North America, where the early Carboniferous beds are primarily marine limestones, the Pennsylvanian was in the past treated as a full-fledged geologic period between the Mississippian and the Permian. In parts of Europe, the Mississippian and Pennsylvanian are one more-or-less continuous sequence of lowland continental deposits and are grouped t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous'' means "coal-bearing", from the Latin '' carbō'' ("coal") and '' ferō'' ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial animal life was well established by the Carboniferous Period. Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, became pentadactylous in and diversified during the Carboniferous, including early amphibian lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian Arachnids
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
