The Myuchelys is a genus of turtles, the Australian saw-shelled turtles, in the family Chelidae and subfamily Chelodininae. 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.
Species The genus currently contains these cryptic small species of freshwater turtles, endemic to eastern and northern Australia:
Myuchelys bellii, Namoi River snapping turtle Gray, 1844Gray, J. E. 1844. Catalogue of the Tortoises, Crocodiles and Amphibaenians in the Collection of the British Museum. London. Edward Newman. 80pp. Myuchelys georgesi, Bellinger River snapping turtle Cann, 1997Cann, J. 1998a. Georges short-neck turtle. Monitor 9(1):18-23. Myuchelys latisternum, saw-shelled turtle Gray, 1867 Myuchelys purvisi, Manning River snapping turtle
Taxonomic history The species Myuchelys latisternum was originally placed in the genus Elseya by Gray in 1867 but Elseya was redefined by George Albert Boulenger in 1889 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 J. 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 in 1844, and was in the genus Phrynops until this oversight was corrected by Cann in 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), 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. .
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. this paper was pointed out by Georges and Thomson to be in breach of the ICZN code defining a valid publication, ICZN Articles 8 and 9 and Recommendation 8D.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. 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, a single taxonomic checklist and by numerous workers in diverse disciplines. In the ensuing time the name Myuchelys has established usage as defined by the ICZN code.
In 2013, Le et al. found that one species, purvisi, was still paraphyletic and proposed a new monophyletic genus to handle this; purvisi was therefore moved to the genus Flaviemys. In 2017, the IUCN TTWG following the recommendation of Spinks et al. (2015) placed Flaviemys as a synonymy of Myuchelys.
References