Saw-shelled turtle

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Saw-shelled turtle
Saw-shelled turtle (Myuchelys latisternum) Daintree.jpg
Daintree rainforest, Queensland
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Pleurodira
Family: Chelidae
Genus: Myuchelys
Species:
M. latisternum
Binomial name
Myuchelys latisternum
(Gray, 1867) [1]
Synonyms [2]
  • Elseya latisternumGray, 1867
  • Euchelymys spinosaGray, 1871
  • Elseya latisternonGray, 1871 ( ex errore )
  • Elseya spinosaGray, 1872
  • Emydura latisternumBoulenger, 1889
  • Elseya latisternum latisternumBlackmore, 1969
Port Douglas, Australia Northern Australian Snapping Turtle (Myuchelys latisternum) (9756835361).jpg
Port Douglas, Australia

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]

Contents

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 Fritz & Havaš 2007. [2] [8]

Reproduction and nesting

Myuchelys latisternum reaches sexual maturity at an SCL of 125–135 mm in males and 182–189 mm in females. Courtship behaviors continue throughout the year but mating is observed during mid January. There is no indication of large congregates of nesting sites, but instead, they are seen in ones or twos at dispersed localities along the watercourse. Nest have been seen in soil as far as 100 m from the water. [9] The females nest from September to December. [10] They can have three to four clutches in one season of 9 to 20 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 × 22 mm)", [3] or as small and "flexible-shelled". [4] Hatchlings from central Queensland measured 30 x 29 mm SCL x carapace width, while hatchlings from northern New South Wales averaged 32.5 × 22.5 mm. [10]

Feeding habits

The saw-shelled turtle is an opportunistic omnivore with a carnivorous preference. It feeds on fish, tadpoles, frogs, bivalves, crustaceans, snails, carrion, and aquatic and terrestrial insects. It is also one of the few native Australian animals successful in preying on the introduced and very poisonous cane toad (Rhinella marina) which is lethal to many freshwater turtles. [3] Toads too large to swallow whole are first shredded with their front claws. [4] They also eat vegetation including fruits, leaves, filamentous algae, and water weed. [10]

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. [11]

Habitat and ecology

Myuchelys latisternum is most often located in headwaters or tributaries of larger rivers in creeks, waterholes, dams, and lakes. However they are a highly adaptable species and have been seen in a variety of landscapes such as savannah woodlands, tropical rainforest, farmland, and semi-urban environments. Can be observed on logs and rocks adjacent to their habitat for basking, it is unknown if this is for thermoregulatory purposes or not. [10]

Related Research Articles

<span class="mw-page-title-main">Chelidae</span> Family of turtles

Chelidae is one of three living families of the turtle suborder Pleurodira, and are commonly called Austro-South American side-neck turtles. The family is distributed in Australia, New Guinea, parts of Indonesia, and throughout most of South America. It is a large family of turtles with a significant fossil history dating back to the Cretaceous. The family is entirely Gondwanan in origin, with no members found outside Gondwana, either in the present day or as a fossil.

<span class="mw-page-title-main">Eastern long-necked turtle</span> Species of turtle

The eastern long-necked turtle is an east Australian species of snake-necked turtle that inhabits a wide variety of water bodies and is an opportunistic feeder. It is a side-necked turtle (Pleurodira), meaning that it bends its head sideways into its shell rather than pulling it directly back.

<i>Chelodina</i> Genus of turtles

Chelodina, collectively known as snake-necked turtles, is a large and diverse genus of long-necked chelid turtles with a complicated nomenclatural history. Although in the past, Macrochelodina and Macrodiremys have been considered separate genera and prior to that all the same, they are now considered subgenera of the Chelodina, further Macrochelodina and Macrodiremys are now known to apply to the same species, hence Chelydera is used for the northern snake-necked turtles.

<span class="mw-page-title-main">Mary River turtle</span> Species of turtle

The Mary River turtle is an endangered short-necked turtle that is endemic to the Mary River in south-east Queensland, Australia. Although these turtles were known to inhabit the Mary River for nearly 30 years, it was not until 1994 that they were recognised as a new species. There has been a dramatic decrease in their population due to low reproduction rates and an increase of depredation on nests.

<span class="mw-page-title-main">Argentine snake-necked turtle</span> Species of turtle

The Argentine snake-necked turtle, also known commonly as the South American snake-necked turtle is a species of turtle in the family Chelidae. The species is known for the long neck to which its common names refer. Despite appearances, the Argentine snake-necked turtle is probably more closely related to the mata mata than to the Australian snake-necked turtles in the genus Chelodina. H. tectifera is found in northern Argentina, Uruguay, Paraguay, and southern Brazil. Not much is known about it, as it has not been extensively researched. It is a popular pet in the exotic pet trade.

<span class="mw-page-title-main">Big-headed pantanal swamp turtle</span> Species of turtle

The big-headed pantanal swamp turtle or pantanal swamp turtle is a species of turtle in the family Chelidae found in Brazil, Bolivia, Argentina, and Paraguay.

The Namoi River snapping turtle, also commonly known as Bell's turtle, the Namoi River elseya, or Bell's saw-shelled turtle, is a species of turtle in the family Chelidae. The species is endemic to New South Wales, Australia.

<i>Elseya</i> Genus of turtles

Elseya is a genus of large side-necked turtles, commonly known as Australian snapping turtles, in the family Chelidae. Species in the genus Elseya are found in river systems in northern and northeastern Australia and throughout the river systems of New Guinea. They are identified by the presence of alveolar ridges on the triturating surfaces of the mouth and the presence of a complex bridge strut.

<i>Elseya branderhorsti</i> Species of New Guinea turtle

Elseya branderhorsti, also known commonly as Branderhorst's turtle and Branderhorst's snapping turtle, is a species of freshwater turtle in the family Chelidae. The species is endemic to southern New Guinea, in West Papua Indonesia and Western Province of Papua New Guinea. Until recently it has been a confusing species due to its lost holotype and its sympatry with another, undescribed, species. E. branderhorsti is currently listed as Vulnerable on the IUCN RedList in part due to its vulnerability to the Asian turtle trade.

<span class="mw-page-title-main">Bellinger River snapping turtle</span> Species of turtle

The Bellinger River turtle is a species of turtle in the family Chelidae. The species is of moderate size, with a straight-line carapace length to 240 mm (9.4 in) in females, and 185 mm (7.3 in) in males. It is endemic to Australia with a highly restricted distribution to the small coastal drainage of the Bellinger River in New South Wales. In the past the species was considered locally abundant. The species' preferred habitat is the deeper pools of the clear-water upstream reaches of the river, where water flows continuously in most months over a bedrock basement and a stream bed of boulders, pebbles, and gravel. A captive breeding program has been under way since a 2015 virus outbreak came close to wiping out the entire species. Most remaining individuals are currently housed in quarantine, though a small number have been reintroduced to the original habitat.

<span class="mw-page-title-main">New Guinea snapping turtle</span> Species of turtle

The Western New Guinea stream turtle or New Guinea snapping turtle is a species of freshwater turtle in the Chelidae family. It is found in the Bird's Head Peninsula and the Bomberai Peninsula west of Cenderawasih Bay, and on the island of Waigeo of West Papua, Indonesia.

<i>Emydura</i> Genus of turtles

Emydura, the Australian short-necked turtles, are a genus of turtles in the family Chelidae. It was paraphyletic with Elseya. Consequently, it was split into two genera Myuchelys and Elseya by Thomson & Georges, 2009. They can grow quite large, 30 cm or more is not unusual and have a life span of around 20–30 years. They generally do not hibernate as their warmer climate lets them remain active all year round; they also spend more time in the water than other varieties. They are considered omnivore but rely on a constant supply of meat to remain healthy, feeding on basically anything that will fit into their mouth.

Dahl's toad-headed turtle is a medium-sized species of side-necked turtle in the family Chelidae. This critically endangered freshwater turtle is endemic to northern Colombia, where it lives in small pools, streams, and swamps, but aestivates on land.

<span class="mw-page-title-main">Vanderhaege's toad-headed turtle</span> Species of turtle

Vanderhaege's toad-headed turtle is a species of turtle in the family Chelidae. The species is endemic to South America.

<span class="mw-page-title-main">Fitzroy River turtle</span> Species of turtle

The Fitzroy River turtle is a species of freshwater turtle in the family Chelidae. It is the only surviving member of the genus Rheodytes, the other member being the extinct form Rheodytes devisi. The species is endemic to south eastern Queensland, Australia and only found in tributaries of the Fitzroy River.

<i>Myuchelys</i> Genus of turtles

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.

<i>Elseya albagula</i> Species of turtle

Elseya albagula, commonly known as the white-throated snapping turtle, is one of the largest species of chelid turtles in the world, growing to about 45 cm (18 in) carapace length.

<span class="mw-page-title-main">Gulf snapping turtle</span> Species of turtle

The Gulf snapping turtle or Lavaracks' turtle is a large species of freshwater turtle in the sidenecked family Chelidae. The species is endemic to northern Australia in northwest Queensland and northeast Northern Territory. The species, similar to other members of the Australian snapping turtles in genus Elseya, only comes ashore to lay eggs and bask. The Gulf snapping turtle is a herbivore and primarily consumes Pandanus and figs.

<i>Elseya dentata</i> Species of turtle

Elseya dentata, the northern snapping turtle, is a large aquatic turtle found throughout many rivers in northern Western Australia and the Northern Territory. It is one of three species in the nominate subgenus Elseya.

<i>Chelodina burrungandjii</i> Species of turtle

Chelodina (Chelydera) burrungandjii, the sandstone snake-necked turtle or Arnhem Land long-necked turtle, is a medium-sized turtle reaching carapace lengths of 316 mm. The species is found in the sandstone plateaus and escarpments and the plunge pools of Arnhem Land of the Northern Territory. The species had been long recognised as valid. However, it had been difficult to research due to the remoteness of its habitat. Efforts to breed this species in captivity had been largely unsuccessful, until National Aquarium Herpetologist Matthew Benedict lead a successful breeding project in 2021. The species occurs in proximity to Chelodina rugosa, to which it is closely related. For the most part the two species are parapatric in distribution. However, they do come together in limited locations such as plunge pools at the base of the escarpments. In these areas there is hybridization between the species.

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. 1 2 Fritz Uwe; Peter Havaš (2007). "Checklist of Chelonians of the World". Vertebrate Zoology. 57 (2): 329. doi: 10.3897/vz.57.e30895 . ISSN   1864-5755. S2CID   87809001.
  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. Freeman, Alastair and John H. Cann. “Myuchelys latisternum (Gray 1867) – Sawshelled Turtle, Saw-Shell Turtle.” (2014).{{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  10. 1 2 3 4 Rhodin, Anders; Pritchard, Peter; van Dijk, Peter Paul; Saumure, Raymond; Buhlmann, Kurt; Iverson, John; Mittermeier, Russell, eds. (2014-01-15). Conservation Biology of Freshwater Turtles and Tortoises (First ed.). Chelonian Research Foundation. doi:10.3854/crm.5.073.latisternum.v1.2014. ISBN   978-0-9653540-9-7.
  11. King, Peter; Heatwole, Harold (1994). "Partitioning of aquatic oxygen uptake among different respiratory surfaces in a freely diving pleurodiran turtle, Elseya latisternum". Copeia. 1994 (3): 802–806. doi:10.2307/1447197. JSTOR   1447197.