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The ''Myuchelys'' is a genus of turtles, the Australian saw-shelled turtles, in the family Chelidae. They inhabit the headwaters and tributaries of rivers within their range and this led to the name ''Myuchelys'', which is formed from the Aboriginal word ''myuna'' meaning clear water and the Greek ''chelys'' meaning turtle.〔 They have a short neck and the intergular scute completely separates the gular scutes. They have no alveolar ridge separating them from the snapping turtles of the genus ''Elseya''. The genus currently contains these cryptic small species of freshwater turtles, endemic to eastern and northern Australia: * Saw-shelled turtle, ''Myuchelys latisternum'' Gray, 1867〔Gray, J.E. 1867. Description of a new Australian tortoise. Annals and Magazine of Natural History. 3(20):43-45〕 * Bellinger River snapping turtle, ''Myuchelys georgesi'' Cann, 1997〔Cann, J. 1998a. Georges short-neck turtle. Monitor 9(1):18-23.〕 * Namoi River snapping turtle, ''Myuchelys bellii'' Gray, 1844〔Gray, J. E. 1844. Catalogue of the Tortoises, Crocodiles and Amphibaenians in the Collection of the British Museum. London. Edward Newman. 80pp.〕 ==Taxonomic history== The species ''M. latisternum'' was originally placed in the genus ''Elseya'' by Gray, 1867〔 but ''Elseya'' was redefined by Boulenger, 1889〔Boulenger, G.A. (1889) Catalogue of the Chelonians, Rhynchocephalians, and Crocodiles in the British Museum (Natural History). British Museum, London.〕 to include species defined by the presence of an alveolar ridge. Hence, ''Myuchelys latisternum'' and ''Myuchelys novaeguineae'' were moved to the genus ''Emydura''. In 1967, the two species were placed back in the genus ''Elseya'' by Goode,〔Goode, J. (1967) Freshwater Tortoises of Australia and New Guinea (in the Family Chelidae). Lansdowne Press, Melbourne.〕 where they remained until recently. During the time, the species ''Myuchelys bellii'' was basically lost to knowledge, having been misidentified as a South American species when described by Gray, 1844,〔 and was in the genus ''Phrynops'' until this oversight was corrected by Cann, 1998.〔Cann, J. (1998) Australian Freshwater Turtles. Beaumont Publishing, Singapore.〕 The species ''Myuchelys georgesi'' and ''Myuchelys purvisi'' were initially placed in the genus ''Elseya'', but were identified as belonging to a unique clade along with ''Myuchelys latisternum'' and ''Myuchelys bellii'' using electrophoresis. The first attempt to separate this group into its own genus was the genus ''Euchelymys'' (Gray, 1871),〔Gray, J.E. (1871) On ''Euchelymys'', a new genus and two new species of Australian freshwater tortoises. Annals and Magazine of Natural History (London), Series 4, 8, 117–118.〕 but this name was subsequently synonymised with ''Elseya'' by Boulenger (1889)〔 and the name was made permanently unavailable when Lindholm (1929)〔Lindholm, W.A. (1929) Revidiertes Verzeichnis der Gattungen der rezenten Schildkröten nebst Notizen zur Nomenklatur einger Arten. Zoologischer Anzeiger, 81, 275–295.〕 set ''Euchelymys sulcifera'' (= ''Emydura macquarii'') as the type species, effectively making the name ''Euchelymys'' a junior synonym of ''Emydura''. Another option investigated was the fossil form ''Pelocomastes'', de Vis 1897;〔de Vis, C.W. 1897. The extinct freshwater turtles of Queensland. Annals of the Queensland Museum. 3: 3-7.〕 the species in this genus may have represented an extinct member of the ''latisternum'' group, but this was determined to be incorrect and the name ''Pelocomastes'' is now considered a junior synonym of ''Elseya''.〔Thomson, S. A. 2000 06 30: A Revision of the Fossil Chelid Turtles (Pleurodira) Described by C.W. De Vis, 1897. Memoires of the Queensland Museum 45(2):593-598. Brisbane. ISSN 0079-8835.〕 The genus name ''Wollumbinia'' was erected by Wells, 2007,〔Wells, R.W. (2007) (Some taxonomic and nomenclatural considerations on the Class Reptilia in Australia. A new genus of the Family Chelidae from eastern Australia. ) "Australian Biodiversity Record", 2007(3), 1–12. ISSN: 1325-2992〕 however, this paper was declared to be in breach of the ICZN code defining a valid publication, ICZN Articles 8 and 9 and Recommendation 8D.〔Georges, A. & Thomson, S. 2010. (Diversity of Australasian freshwater turtles, with an annotated synonymy and keys to species. ) Zootaxa 2496: 1–37.〕〔Fritz, U. & Havaš, P. (2007) (Checklist of Chelonians of the World. ) Vertebrate Zoology (Dresden), 57, 149–368.〕 As such this name is not considered valid.〔〔〔Anders G.J. Rhodin, Peter Paul van Dijk, John B. Iverson, and H. Bradley Shaffer. 2010. (Turtles of the World, 2010 Update: Annotated Checklist of Taxonomy, Synonymy, Distribution, and Conservation Status )〕 The genus encompassing these species was named ''Myuchelys'' by Thomson and Georges, 2009.〔 Currently, this arrangement is considered the accepted name for the ''latisternum'' group by the IUCN,〔 multiple taxonomic checklists〔 and by numerous workers in diverse disciplines.〔Fielder D, Vernes K, Alacs E, Georges A (2012) Mitochondrial variation among Australian freshwater turtles (genus ''Myuchelys''), with special reference to the Endangered ''M. bellii''. Endang Species Res 17:63-71〕〔Georges A, Spencer RJ, Welsh M, Shaffer HB, Walsh R, Zhang X (2011) Application of the precautionary principle to taxa of uncertain status: the case of the Bellinger River turtle. Endang Species Res 14:127-134〕 In 2013, Le ''et al''.〔Le, M., Reid, B., N., McCord, W., P., Naro-Maciel, E., Raxworthy, C., J., Amato, G., Georges A., 2013. Resolving the phylogenetic history of the short-necked turtles, genera Elseya and Myuchelys (Testudines: Chelidae) from Australia and New Guinea. ''Molecular Phylogenetics and Evolution''. 68 (2013) 251–258.〕 found that one species was still paraphyletic and proposed a new monophyletic genus to handle this. The Manning River turtle was therefore moved to the genus ''Flaviemys''. 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「Myuchelys」の詳細全文を読む スポンサード リンク
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