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Scytodoidea
Scytodoidea is a taxon of araneomorph spiders, at the rank of superfamily. It contains four families: * Drymusidae * Periegopidae * Scytodidae * Sicariidae Phylogeny The monophyly of the group has been confirmed in morphological studies. One hypothesis for the relationships of the four families is shown in the following cladogram: Earlier studies agree in placing the Sicariidae as the most basal family, but reverse the positions of Drymusidae and Scytodidae. Scytodoidea is placed within the haplogyne The Haplogynae or haplogynes are one of the two main groups into which araneomorph spiders have traditionally been divided, the other being the Entelegynae. Morphological phylogenetic studies suggested that the Haplogynae formed a clade; more rece ... clade of araneomorph spiders, as one of the more derived clades. References {{Taxonbar, from=Q54911 Arachnid superfamilies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scytodoidea
Scytodoidea is a taxon of araneomorph spiders, at the rank of superfamily. It contains four families: * Drymusidae * Periegopidae * Scytodidae * Sicariidae Phylogeny The monophyly of the group has been confirmed in morphological studies. One hypothesis for the relationships of the four families is shown in the following cladogram: Earlier studies agree in placing the Sicariidae as the most basal family, but reverse the positions of Drymusidae and Scytodidae. Scytodoidea is placed within the haplogyne The Haplogynae or haplogynes are one of the two main groups into which araneomorph spiders have traditionally been divided, the other being the Entelegynae. Morphological phylogenetic studies suggested that the Haplogynae formed a clade; more rece ... clade of araneomorph spiders, as one of the more derived clades. References {{Taxonbar, from=Q54911 Arachnid superfamilies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drymusidae
Drymusidae is a family of araneomorph spiders first described by Eugène Simon in 1893, and elevated to family status by Pekka T. Lehtinen in 1986. Genera , the World Spider Catalog accepts the following genera: *''Drymusa ''Drymusa'' is a genus of false violin spiders that was first described by Eugène Simon in 1892. They physically resemble violin spiders (''Loxosceles''), but their bites are not believed to be medically significant. Originally placed with t ...'' Simon, 1892 — Caribbean, Costa Rica, South America *'' Izithunzi'' Labarque, Pérez-González & Griswold, 2018 — South Africa References Araneomorphae families {{araneomorphae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxon
In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in '' Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araneomorphae
The Araneomorphae (also called the Labidognatha) 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 of living spiders. Distinguishing characteristics Most spider species are Araneomorphae, which have fangs that face towards each other, increasing the orientations they can employ during prey capture. They have fewer book lungs (when present), and the females typically live one year. The Mygalomorphae have 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 four pairs of book lungs, and the females often live many years. Image:Atrax robustus.jpg, This ''Atrax robustus'' shows the orientation of Myglamorphae fangs. Image:C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. , 50,356 spider species in 132 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel, however, as there is currently neither paleontological nor embryological evidence that spiders ever had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxonomic Rank
In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in an ancestral or hereditary hierarchy. A common system consists of species, genus, family, order, class, phylum, kingdom, domain. While older approaches to taxonomic classification were phenomenological, forming groups on the basis of similarities in appearance, organic structure and behaviour, methods based on genetic analysis have opened the road to cladistics. A given rank subsumes under it less general categories, that is, more specific descriptions of life forms. Above it, each rank is classified within more general categories of organisms and groups of organisms related to each other through inheritance of traits or features from common ancestors. The rank of any ''species'' and the description of its ''genus'' is ''basic''; which means that to identify a particular organism, it is usually not necessary to specify ranks other than these first two. Consider a parti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family ( la, familia, plural ') is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, but in plants, they can be characterized on the basis of both vegetative and reproductive features of plant species. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periegopidae
''Periegops'' is a genus of spiders with six eyes instead of the usual eight. It is the only genus in its family (Periegopidae) and has three described species. It was long considered to be members of Sicariidae or Segestriidae until Raymond Forster elevated them to the family level in 1995. Taxonomy ''Periegops'' was first described in 1893 by Eugene Simon from a specimen of ''P. hirsutus'' (A synonym of ''P. suterii'').Simon, E. (1893a). ''Histoire naturelle das araignées''. Paris 1, 257-488. doi:10.5962/bhl.title.51973 Description This genus of spider has only six eyes, as opposed to eight, which is typical for spiders. Body length varies from 5.9mm to 10mm depending on species and sex. Carapace is an orange colour and is darker on the anterior side. Abdomen is brown or creamy brown and usually have a chevron pattern. The family can be distinguished by the pattern of eye positions, which are in three clusters of two eyes. Species , the World Spider Catalog The World S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scytodidae
Spitting spiders (Scytodidae) is a family of araneomorph spiders first described by John Blackwall in 1864. It contains over 250 species in five genera, of which ''Scytodes'' is the best-known. Description Like recluse spiders and coneweb spiders, they have six eyes arranged in three pairs and are haplogyne, meaning they have less complex female genitalia. They differ from these families in having a dome-shaped carapace and in their characteristic flecked pattern of spots. Hunting technique Scytodidae catch their prey by spitting a fluid that congeals on contact into a venomous and sticky mass. The fluid contains both venom and spider silk in liquid form, though it is produced in venom glands in the chelicerae. The venom-laced silk both immobilizes and envenoms prey such as silverfish. In high-speed footage the spiders can be observed swaying from side to side as they "spit", catching the prey in a criss-crossed "Z" pattern; it is criss-crossed because each of the chelicera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sicariidae
Sicariidae is a family of six-eyed venomous spiders known for their potentially necrotic bites. The family consists of three genera and about 160 species. Well known spiders in this family include the brown recluse spider and the six-eyed sand spider. Description '' Loxosceles'', commonly known as "recluse spiders" or "violin spiders", is distributed nearly worldwide in warmer areas. '' Hexophthalma'' and '' Sicarius'', commonly known as "sand spiders" or "assassin spiders", live in the deserts of southern Africa and South to Central America, respectively. They are known for their self-burying behavior and the ability to go for long periods without food or water. All members have six eyes arranged in three groups of two (dyads). Violin spiders are usually brownish with a darker brown characteristic violin marking on the cephalothorax. They are also haplogyne, meaning the females possessing unsclerotised genitals. ''Hexophthalma'' and ''Sicarius'' resemble crab spiders and l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyly
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic groups are typically characterised by shared derived characteristics ( synapomorphies), which distinguish organisms in the clade from other organisms. An equivalent term is holophyly. The word "mono-phyly" means "one-tribe" in Greek. Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic group'' consists of all of the descendants of a common ancestor minus one or more monophyletic groups. A '' polyphyletic group'' is characterized by convergent features or habits of scientific interest (for example, night-active primates, fruit trees, aquatic insects). The features by which a polyphyletic group is differentiated from others are not inherited from a common ancestor. These definitions have tak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
