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Exechocentrus
''Exechocentrus'' is a genus of Madagascan orb-weaver spiders (family Araneidae) first described by Eugène Simon in 1889. It is a bolas-using spider, capturing its prey with one or more sticky drops at the end of a single line of silk rather than in a web. Description Males of the genus are unknown. Females can be distinguished from all other known members of the family Araneidae by the spine-like projections on the cephalothorax. One is centrally placed and extends forwards; three are more-or-less upright. The total body length is . The cephalothorax is yellowish-white with brown lines radiating from the fovea and is about as wide as it is long. The legs are pale yellowish-white with dark brown markings. The abdomen is off white and almost heart-shaped from above. The epigyne has a strongly hardened (sclerotized) lip. The spermathecae are large and ovoid, with short narrow copulatory ducts. Taxonomy The genus ''Exechocentrus'' was erected by Eugène Simon in 1889 for the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exechocentrus Madilina
''Exechocentrus'' is a genus of Madagascan orb-weaver spiders (family Araneidae) first described by Eugène Simon in 1889. It is a bolas-using spider, capturing its prey with one or more sticky drops at the end of a single line of silk rather than in a web. Description Males of the genus are unknown. Females can be distinguished from all other known members of the family Araneidae by the spine-like projections on the cephalothorax. One is centrally placed and extends forwards; three are more-or-less upright. The total body length is . The cephalothorax is yellowish-white with brown lines radiating from the fovea and is about as wide as it is long. The legs are pale yellowish-white with dark brown markings. The abdomen is off white and almost heart-shaped from above. The epigyne has a strongly hardened (sclerotized) lip. The spermathecae are large and ovoid, with short narrow copulatory ducts. Taxonomy The genus ''Exechocentrus'' was erected by Eugène Simon in 1889 for the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exechocentrus Lancearius
''Exechocentrus lancearius'' is a species of spider in the orb-weaver spider family Araneidae, found only in Madagascar. It was initially described from a partial specimen of an adult female. The first description of a complete specimen and its prey-catching behaviour was published in 2012. ''E. lancearius'' is a bolas spider. Rather than using a web, adult females catch their prey by using a line with one or two sticky drops (a "bolas") which they swing. Description The neotype female was described by Scharff and Hormiga in 2012. The total length of the body is 3.9 mm. The cephalothorax is about 2.0 mm long and wide, and the abdomen 2.7 mm long and 3.9 mm wide. (The abdomen overlaps the cephalothorax.) The cephalothorax is pear-shaped and has four spine-like projections, one pointing forwards and three in a triangle behind it. The carapace is yellowish white with a white central stripe and dark brown markings. The sternum is blackish brown. The legs ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolas Spider
A bolas spider is a member of the orb-weaver spider (family Araneidae) that, instead of spinning a typical orb web, hunts by using one or more sticky "capture blobs" on the end of a silk line, known as a " bolas". By swinging the bolas at flying male moths or moth flies nearby, the spider may snag its prey rather like a fisherman snagging a fish on a hook. Because of this, they are also called angling or fishing spiders (although the remotely related genus '' Dolomedes'' is also called a fishing spider). The prey is lured to the spider by the production of up to three sex pheromone-analogues. Bolas spiders have been treated as either the whole or part of either the tribe "Mastophoreae" or Mastophorini, the subfamily Mastophorinae, or the informal group mastophorines. Recent studies show that the genus '' Celaenia'', which does not use a bolas, belongs in the same taxonomic group. Description Bolas spiders are small nocturnal animals with conspicuous outgrowths on the upper ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrtarachninae
Cyrtarachninae is a subfamily of spiders in the family Araneidae (orb-weaver spiders, araneids). The group has been circumscribed in several different ways. It originated as the group Cyrtarachneae, described by Eugène Simon in 1892. The group was later treated at different ranks: as a tribe, both under Simon's name and as Cyrtarachnini, and as the subfamily Cyrtarachninae. Circumscriptions have varied. The broadest circumscription, Cyrtarachninae ''sensu lato'' (''s.l.''), includes three of Simon's original groups, including the bolas spiders (also placed in the tribe Mastophoreae or Mastophorini, or in the subfamily Mastophorinae). Unlike most araneids, members of the subfamily do not construct orb webs, some not using webs at all to capture prey, some using one or more sticky drops on a single line (a bolas), while others construct webs with few widely spaced non-spiral threads, some triangular. Many have been shown to attract prey by producing analogues of insect sex pheromo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orb-weaver Spider
Orb-weaver spiders are members of the spider family (biology), family Araneidae. They are the most common group of builders of spiral wheel-shaped spider web, webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name of the group. Araneids have eight similar eyes, hairy or spiny legs, and no stridulation, stridulating organs. The family has a cosmopolitan distribution, including many well-known large or brightly colored garden spiders. With 3,108 species in 186 genus, genera worldwide, the Araneidae comprise the third-largest family of spiders (behind the Salticidae and Linyphiidae). Araneid webs are constructed in a stereotypical fashion, where a framework of nonsticky spider silk, silk is built up before the spider adds a final spiral of silk covered in sticky droplets. Spider web#Orb web construction, Orb webs are also produced by members of other spider families. The long-jawed orb weavers (Tetragnathidae) were former ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araneidae
Orb-weaver spiders are members of the spider family Araneidae. They are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name of the group. Araneids have eight similar eyes, hairy or spiny legs, and no stridulating organs. The family has a cosmopolitan distribution, including many well-known large or brightly colored garden spiders. With 3,108 species in 186 genera worldwide, the Araneidae comprise the third-largest family of spiders (behind the Salticidae and Linyphiidae). Araneid webs are constructed in a stereotypical fashion, where a framework of nonsticky silk is built up before the spider adds a final spiral of silk covered in sticky droplets. Orb webs are also produced by members of other spider families. The long-jawed orb weavers ( Tetragnathidae) were formerly included in the Araneidae; they are closely related, being part of the superfamily Aran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugène Simon
Eugène Louis Simon (; 30 April 1848 – 17 November 1924) was a French naturalist who worked particularly on insects and spiders, but also on birds and plants. He is by far the most prolific spider taxonomist in history, describing over 4,000 species. Work on spiders His most significant work was ''Histoire Naturelle des Araignées'' (1892–1903), an encyclopedic treatment of the spider genera of the world. It was published in two volumes of more than 1000 pages each, and the same number of drawings by Simon. Working at the Muséum National d'Histoire Naturelle in Paris, it took Simon 11 years to complete, while working at the same time on devising a taxonomic scheme that embraced the known taxa. Simon described a total of 4,650 species, and as of 2013 about 3,790 species are still considered valid. The International Society of Arachnology offers a Simon Award recognising lifetime achievement. The Eocene The Eocene ( ) Epoch is a geological epoch that lasted from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus '' Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa across the Mozambique Channel. At Madagascar is the world's second-largest island country, after Indonesia. The nation is home to around 30 million inhabitants and consists of the island of Madagascar (the fourth-largest island in the world), along with numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from the Indian subcontinent around 90 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, Madagascar is a biodiversity hotspot; over 90% of its wildlife is endemic. Human settlement of Madagascar occurred during or before the mid first millennium AD by Austronesian peoples, presumably arriving on outrigger cano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossary Of Spider Terms
This glossary describes the terms used in formal descriptions of spiders; where applicable these terms are used in describing other arachnids. Links within the glossary are shown . Terms A Abdomen or opisthosoma: One of the two main body parts ( tagmata), located towards the posterior end; see also Abdomen § Other animals Accessory claw: Modified at the tip of the in web-building spiders; used with to grip strands of the web Anal tubercle: A small protuberance (tubercule) above the through which the anus opens Apodeme → Apophysis (plural apophyses): An outgrowth or process changing the general shape of a body part, particularly the appendages; often used in describing the male → Atrium (plural atria): An internal chamber at the entrance to the in female haplogyne spiders B Bidentate: Having two Book lungs: Respiratory organs on the ventral side (underside) of the , in front of the , opening through narrow slits; see also Book lungs Branchial operculum â ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Phylogenetics
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to determine the processes by which diversity among species has been achieved. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree. Molecular phylogenetics is one aspect of molecular systematics, a broader term that also includes the use of molecular data in taxonomy and biogeography. Molecular phylogenetics and molecular evolution correlate. Molecular evolution is the process of selective changes (mutations) at a molecular level (genes, proteins, etc.) throughout various branches in the tree of life (evolution). Molecular phylogenetics makes inferences of the evolutionary relationships that arise due to molecular evolution and results in the construction of a phylogenetic tree. History The theoretical f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
