Saw-shelled turtle

Saw-shelled turtle
Not evaluated (IUCN 3.1)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Family: Chelidae
Subfamily: Chelodininae
Genus: Myuchelys
Species: M. latisternum
Binomial name
Myuchelys latisternum
(Gray, 1867)[1]
Synonyms[2]
  • Elseya latisternum Gray, 1867
  • Euchelymys spinosa Gray, 1871
  • Elseya latisternon Gray, 1871 (ex errore)
  • Elseya spinosa Gray, 1872
  • Emydura latisternum Boulenger, 1889
  • Elseya latisternum latisternum Blackmore, 1969

The saw-shelled turtle, Myuchelys latisternum, is a species of turtle in the Chelidae family endemic to Australia, ranging along rivers and streams and connected swamps and lagoons from coastal Cape York Peninsula to northern New South Wales, with populations also noted as far south as Newcastle - (Williams River Catchment site of the former Tilligra Dam). They are thought to have been introduced to Lake Eacham in the Atherton Tablelands. Other common English names are: serrated snapping turtle or common sawshell turtle.[3][4]

Description

The female is considerably larger than the male, with a carapace up to 28 cm long compared to the males which rarely get longer than about 18 cm. The carapace is roughly oval and broad at the rear.[3][4] They are not usually aggressive, but can bite fiercely. They can also emit a strong smell.[4]

The shell has marginal serrations which are the reason for its common name. It retains some of these serrations throughout its life. "The head shield extends down the side of the head to just above the tympanum, and the top of the neck has prominent pointed tubercules (many of these with an apical sensory pit)."[4]

The carapace is mainly brown to dark brown, commonly with some dark blotches. The plastron (underside) is yellowish. The head is large with a projecting snout and a horny plate on the top. The neck can fold sideways. The feet are webbed and also clawed. Hatchlings have serrated hind legs which become smooth as they mature.[5]

Nomenclatural history

Myuchelys latisternum (Gray, 1867) (common sawshell turtle)

follows that of Gray (1872a) and Boulenger (1889).[6]

The combination Wollumbinia latisternum (Gray, 1867) Wells, 2007, was declared unpublished and hence unavailable for use by Georges & Thomson, 2010.[8]

Nesting

The females nest from September to December. They can have three to four clutches in one season of 9 to 36 eggs which hatch before winter in about 60 days, with the incubation period shortened in southern regions.[4] The eggs are variably described as either "hard-shelled (34 X 22 mm)",[3] or as small and "flexible-shelled".[4]

Feeding habits

The saw-shelled turtle is carnivorous and feeds on fish, tadpoles, frogs, and aquatic insects, and is one of the few native Australian animals successful in preying on the introduced and very poisonous cane toad (Bufo marinus).[3] Toads too large to swallow whole are first shredded with their front claws.[4]

Behaviour

Like many other aquatic turtles, the saw-shelled turtle is able to obtain oxygen from water through skin, cloaca, and buccopharyngeal cavity, thus extending its ability to stay under water for prolonged periods.[9]

References

  1. 1 2 Gray, J.E. 1867. Description of a new Australian tortoise. Annals and Magazine of Natural History. 3(20):43-45
  2. ↑ Fritz Uwe; Peter Havaš (2007). "Checklist of Chelonians of the World". Vertebrate Zoology. 57 (2): 329. ISSN 1864-5755. Archived from the original (PDF) on 2010-12-17. Retrieved 29 May 2012.
  3. 1 2 3 4 Ryan, Michelle, General Editor. (2000). Wildlife of Tropical North Queensland: Cooktown to Mackay. Queensland Museum. ISBN 0-7242-9349-3.
  4. 1 2 3 4 5 6 7 Ehmann, Harold (1992). Encyclopedia of Australian Animals: Reptiles. Angus&Robertson. ISBN 0-207-17379-6 (Reptiles)
  5. ↑ Elseya latisternum
  6. ↑ Gray, J.E. 1871. On Euchelymys a new genus and two new species of Australian freshwater tortoises. Annals and Magazine of Natural History. (4)8:117-118.
  7. ↑ 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.
  8. ↑ Georges, A. & Thomson, S. 2010. Diversity of Australasian freshwater turtles, with an annotated synonymy and keys to species. Zootaxa 2496: 1–37.
  9. ↑ King, Peter; Heatwole, Harold (1994). "Partitioning of aquatic oxygen uptake among different respiratory surfaces in a freely diving pleurodiran turtle, Elseya latisternum". Copeia. 1994: 802–806. doi:10.2307/1447197. JSTOR 1447197.
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