Myuchelys

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.[2] 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.

Myuchelys
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Pleurodira
Family: Chelidae
Subfamily: Chelodininae
Genus: Myuchelys
Thomson and Georges, 2009[1][2]
Synonyms
  • Flaviemys
    Le, Reid, McCord, Naro-Maciel, Raxworthy, Amato, and Georges, 2013:257[1]

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, 1844[3]
  • Myuchelys georgesi, Bellinger River snapping turtle Cann, 1997[4]
  • Myuchelys latisternum, saw-shelled turtle Gray, 1867[5]
  • Myuchelys purvisi[1]

Taxonomic history

The species M. latisternum was originally placed in the genus Elseya by Gray in 1867[5] but Elseya was redefined by George Albert Boulenger in 1889[6] 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,[7] 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,[3] and was in the genus Phrynops until this oversight was corrected by Cann in 1998.[8] 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.[9]

The first attempt to separate this group into its own genus was the genus Euchelymys (Gray, 1871),[10] but this name was subsequently synonymised with Elseya by Boulenger (1889)[6] and the name was made permanently unavailable when Lindholm (1929)[11] 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;[12] 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.[13]

The genus name Wollumbinia was erected by Wells, 2007,[14] 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.[15][16] As such this name is not considered valid.[15][16][17] The genus encompassing these species was named Myuchelys by Thomson and Georges, 2009.[2] Currently, this arrangement is considered the accepted name for the latisternum group by the IUCN,[17] multiple taxonomic checklists[16] and by numerous workers in diverse disciplines.[18][19] In the ensuing time the name Myuchelys has established usage as defined by the ICZN code, with many research papers using it and almost none using alternatives. It is therefore unlikely to be replaced and would require a decision of the ICZN now to do so.

In 2013, Le et al.[20] 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.[1]

gollark: This is cool at 2x speed.
gollark: Or humans or some other species will beat entropy, hack the universe and stop anything from dying ever.
gollark: I mean, ultimately, long after the last stars burn out, the fuel of giant stars of the bright, early universe we live in having long been exhausted, giving way to red dwarves which will themselves slowly fade to black, the matter in them having decayed (possibly), there will be nothing but slowly evaporating black holes. And eventually even these will vanish, leaving nothing but electromagnetic radiation being slowly redshifted, with no energy gradients able to sustain life.
gollark: Sure!
gollark: I mean, death won't happen forever.

References
  1. Rhodin, Anders G.J.; Inverson, John B.; Roger, Bour; Fritz, Uwe; Georges, Arthur; Shaffer, H. Bradley; van Dijk, Peter Paul (August 3, 2017). "Turtles of the world, 2017 update: Annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status(8th Ed.)" (PDF). Chelonian Research Monographs. 7. ISBN 978-1-5323-5026-9. Retrieved October 4, 2019.
  2. Thomson, S. & Georges, A. (2009) Myuchelys gen. nov. —a new genus for Elseya latisternum and related forms of Australian freshwater turtle (Testudines: Pleurodira: Chelidae) Zootaxa 2053: 32–42.
  3. Gray, J. E. 1844. Catalogue of the Tortoises, Crocodiles and Amphibaenians in the Collection of the British Museum. London. Edward Newman. 80pp.
  4. Cann, J. 1998a. Georges short-neck turtle. Monitor 9(1):18-23.
  5. Gray, J.E. 1867. Description of a new Australian tortoise. Annals and Magazine of Natural History. 3(20):43-45
  6. Boulenger, G.A. (1889) Catalogue of the Chelonians, Rhynchocephalians, and Crocodiles in the British Museum (Natural History). British Museum, London.
  7. Goode, J. (1967) Freshwater Tortoises of Australia and New Guinea (in the Family Chelidae). Lansdowne Press, Melbourne.
  8. Cann, J. (1998) Australian Freshwater Turtles. Beaumont Publishing, Singapore.
  9. Georges, A. & Adams, M. (1992). "A phylogeny for Australian chelid turtles based on allozyme electrophoresis". Australian Journal of Zoology. 40 (5): 453–476. doi:10.1071/zo9920453.
  10. 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.
  11. Lindholm, W.A. (1929) Revidiertes Verzeichnis der Gattungen der rezenten Schildkröten nebst Notizen zur Nomenklatur einger Arten. Zoologischer Anzeiger, 81, 275–295.
  12. de Vis, C.W. 1897. The extinct freshwater turtles of Queensland. Annals of the Queensland Museum. 3: 3-7.
  13. 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.
  14. 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
  15. Georges, A. & Thomson, S. 2010. Diversity of Australasian freshwater turtles, with an annotated synonymy and keys to species. Zootaxa 2496: 1–37.
  16. Fritz, U. & Havaš, P. (2007) Checklist of Chelonians of the World. Archived 2016-01-16 at the Wayback Machine Vertebrate Zoology (Dresden), 57, 149–368.
  17. 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
  18. 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. Endanger Species Res 17:63-71
  19. 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. Endanger Species Res 14:127-134
  20. 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.
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