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''Nothomyrmecia'', also known as the dinosaur ant or dawn ant, is a rare genus of ants consisting of a single species, ''Nothomyrmecia macrops''. A member of the subfamily Myrmeciinae, two workers were collected in 1931 near the Russell Range from Israelite Bay in Western Australia and Australian entomologist John S. Clark described it in 1934, but doubts surround the presumed discovery site. The ant lives in South Australia, nesting in old-growth mallee woodland and ''Eucalyptus'' woodland. The ant only remained in literature and from two specimens collected until a group of entomologists rediscovered it 46 years later, away from the original site. Due to species' restricted distribution and potential threats to its survival, the IUCN lists the ant as Critically Endangered. Some entomologists have suggested a relationship to the Baltic Eocene fossil ant genus ''Prionomyrmex'' based on morphological similarities, but this interpretation is not widely accepted by the entomological community. The ant is sometimes referred as a living fossil because of its primitive body structure, stimulating several studies on its morphology, behaviour, ecology, and chromosomes. The average length of this species is , and polymorphism does not occur among the castes. A queen will mate with one or more males, and during colony foundation she will hunt for food until the brood have fully developed. Queens are univoltine and only produce a single generation of ants annually. Two queens may find a colony together, but only one will remain once the first generation of workers arrives. Mature colonies are very small, with only 50 to 100 individuals in each nest. Workers are strictly nocturnal and only forage during cold nights, collecting arthropod prey and sweet substances such as honeydew from Hemiptera insects. They are solitary foragers and rely on their vision to navigate, and no evidence suggests that they use chemicals to communicate. Potential predatory threats are restricted to other ants. ==Taxonomy== ''Nothomyrmecia'' was originally discovered by Amy Crocker in December 1931, based on two syntype workers presumably collected near the Russell Range from Israelite Bay in Western Australia.〔 However, entomologist Robert W. Taylor expressed doubt about the original discovery site of the ant, stating the specimens were probably collected from the western end of the Great Australian Bight, south from Balladonia.〔 No precise data as to where Crocker collected the insects she sent to Australian entomologist John S. Clark is available, but the locations Clark provided had no ''Nothomyrmecia'' colonies present. Despite searches, a 2012 report discussing the possible abundance of ''Nothomyrmecia'' in Western Australia did not confirm any sighting of the ant between Balladonia and the Western Australian coastal regions. After decades of Australian and American collectors failing to find ''Nothomyrmecia'', Taylor and his party of entomologists from Canberra found a solitary worker in 1977 at Poochera, southeast of Ceduna, 1300 km (800 mi) from the site of the 1931 discovery.〔 Currently, Poochera is probably the only town in the world with ant-based tourism, stenciling ''Nothomyrmecia'' along the streets. Entomologists dub the ant as the "holy grail" of myrmecology after 46 years of searching for it. John S. Clark described ''Nothomyrmecia'' in 1934 as a new genus of Myrmeciinae, though with some hesitation due to its apparent similarity with the Eocene Baltic amber fossil ''Prionomyrmex'' unknown to him and of which remained only literature descriptions and figures.〔 The type material is currently housed in the National Museum of Victoria in Melbourne. In 1944, British myrmecologist Horace Donisthorpe moved ''Nothomyrmecia'' to the subfamily Ponerinae, suggesting that all bulldog ants are Ponerine. In 1951, Clark proposed the new ant subfamily Nothomyrmeciinae for his ''Nothomyrmecia'', based on morphological differences with the other Myrmeciinae. With this proposal, Clark assigned ''Nothomyrmecia'' to the newly established tribe Nothomyrmeciini. The rediscovery of the species in 1977 confirmed Clark's placement of ''Nothomyrmecia'' in isolated position within the Formicidae was universally accepted by the scientific community until 2000. In 1985, American entomologists George Wheeler and Jeanette Wheeler placed ''Nothomyrmecia'' back into Myrmeciinae, but a 1988 publication transferred it back into its own subfamily. The single waist node and other features such a non-tubulated fourth abdominal segment led scientists to believe that ''Nothomyrmecia'' should be separate from ''Myrmecia'' and retain Clark's original proposal by classifying the ant in its own subfamily, despite many familiar morphological characteristics between the two genera.〔 In 2000, Cesare Baroni Urbani described a new Baltic fossil ''Prionomyrmex'' species. After examining specimens of ''N. macrops'', Baroni Urbani stated that his new species and ''N. macrops'' belonged to the same genus, and the name ''Prionomyrmex'' would replace the name ''Nothomyrmecia'' and the subfamily Nothomyrmeciinae must be called Prionomyrmeciinae. Baroni Urbani states that ''Prionomyrmex'' is a paraphyletic relative to ''Nothomyrmecia'', and the two genera were so morphologically similar that ''Nothomyrmecia'' must be synonymised. In 2003, Dlussky & Perfilieva separated ''Nothomyrmecia'' from ''Prionomyrmex'' on the base of the fusion of an abdominal segment. In the same year Ward & Brady reached the same conclusion as Dlussky & Perfileeva and provided strong support for the monophyly of ''Prionomyrmex'', and in addition, transferred both taxons as distinct genera in the older subfamily Myrmeciinae.〔 Later, Dlussky also refers only to Ward & Brady’s classification.〔 However, Baroni Urbani suggested additional evidence in favour of his former interpretation as opposed to that of Ward & Brady’s arguments. This view, however, is not supported in subsequent relevant papers, which continue to use the classification of Ward & Brady, rejecting that of Baroni Urbani.〔〔 The ant is commonly known as the dinosaur ant or the dawn ant because it is sometimes referred as a living fossil.〔 Its specific epithet, ''macrops'' derives from the Greek words ''makros'' and ''ops'', meaning "long, large" and "eyes". ''Nothomyrmecia'' and a Ponerinae ant, ''Platythyrea tricuspidata'', share the highest number of chromosomes within Hymenoptera, with a diploid chromosome number 92–94. Studies show that all Hymenoptera insects with a 2n above 52 are ants. ''Nothomyrmecia'' ants have dot-like acrocentric chromosomes, but metacentric chromosomes are sometimes present.〔 Genetic evidence suggests that the age of the most recent common ancestor for ''Nothomyrmecia'' and ''Myrmecia'' is 74 million years old, giving a likely origin in the Cretaceous.〔 In the Evans' vespoid scala, ''Nothomyrmecia'' and other primitive ant genera such as ''Amblyopone'' and ''Myrmecia'' exhibit behaviour similar to a clade of soil-dwelling families of vespoid wasps. The following cladogram generated by Archibald and colleagues shows the possible phylogenetic position of ''Nothomyrmecia'' among some ants of the subfamily Myrmeciinae. They suggest that ''Nothomyrmecia'' may be closely related to extinct Myrmeciinae ants such as ''Avitomyrmex'', ''Macabeemyrma'', ''Prionomyrmex'' and ''Ypresiomyrma''. }} }} 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nothomyrmecia」の詳細全文を読む スポンサード リンク
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