Western swamp turtle (Pseudemydura umbrina)

Also known as: Western short-necked turtle
Synonyms: Emydura inspectata
  
French: Pseudémydure de Perth, Tortue à col court
Spanish: Tortuga Serpentina Occidental
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderTestudines
FamilyChelidae
GenusPseudemydura (1)
SizeMale weight: up to 0.55 kg (2)
Female weight: up to 0.41 kg (2)
Male carapace length: up to 155 mm (2)
Female carapace length: up to 135 mm (2)

Classified as Critically Endangered (CR) on the IUCN Red List 2007 (1).

This small freshwater turtle is the most endangered Australian reptile (3). The flattened carapace appears square from above (2) and varies in colour from yellow-brown to black depending on the area (4). The flattened head is covered by a single large bony plate, or scute (2). Unusually amongst turtles, the female is smaller than the male (4). The plastron, or undershell, of the western swamp turtle is paler than the carapace and extremely broad (2); it often has a pattern of black spots on a yellow background (4). The short legs are covered with bony plates and the feet are clawed (4).

Endemic to Western Australia, this turtle has probably never been very abundant. First discovered in 1839, the species was believed to be extinct until a Perth schoolboy 'rediscovered' the turtle in 1953 (6). At this time the species was restricted to a narrow region of the Swan Coastal Plain near Perth in Western Australia, and today it is found only in two protected sites at the edge of the city: Ellen Brook Nature Reserve, and an introduced population at Twin Swamps (2).

The western swamp turtle inhabits shallow, temporary swamps that are only available after the autumn rains, and which occur on clay or sand-over-clay soils (4).

The western swamp turtle is only active for half the year, spending the dry summer months in a dormant state known as aestivation (4). Within the Ellen Brook Nature Reserve individuals tend to aestivate in holes in the clay soil whilst turtles at Twin Swamps Nature Reserve are more commonly found seeking protection under leaf litter or fallen branches (4). The swamps begin to fill up with water in June and July, when turtles can be found foraging for live food including insect larvae, earthworms and tadpoles (2). As temperatures rise the turtles increase their food intake, putting on excess fat for the months of dormancy to come (4). By November, the swamps are drying out and the turtles leave the water to aestivate through the summer and autumn (4).

Western swamp turtles are unusual in that they only produce one clutch of eggs per year and they are the only turtles to dig a nest with their front, rather than back, flippers (4). In November and early December, three to five hard-shelled eggs are laid into the nest, and are then covered. Eggs will stay in the nest for the summer months; hatchlings emerging the following winter (2). It is thought that western swamp turtles may live for as long as 60 or 70 years (5).

This turtle has always had a restricted distribution; the species depends on marginal habitat and has low reproductive potential (4). Today however, the western swamp turtle is Critically Endangered and the population at Twin Swamps became extinct in 1985 (4). The swamps of this turtles' habitat have been drained and filled in for agricultural purposes, greatly reducing the available range (6). In addition, the population at Twin Swamps in particular, suffered from predation by the introduced red fox (Vulpes vulpes); aestivating individuals protected only by leaf litter are especially vulnerable (6).

The two remaining swamps containing this species were made into nature reserves in 1962, and a captive breeding programme at Perth Zoo has been running since 1988 (6). The captive population has been used to re-establish a viable population of western swamp turtles within the Twin Swamps Reserve (4). A fox-proof fence has been constructed around remaining swamps to provide further protection (4). The Western Swamp Turtle Recovery Plan has been running since 1992, it aims to at least double the population of this rare turtle in 10 years, and to establish a captive population of at least 50 individuals (4).

For more on the western swamp turtle and its conservation see:

Burbidge, A.A. and Kuchling, G. (1994) Western Swamp Tortoise Recovery Plan, Wildlife Management Program No 11. Department of Conservation Land Management, Western Australia. Available at:
www.environment.gov.au/biodiversity/threatened/publications/recovery/swamp-tortoise/index.html

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (June, 2008)
    http://www.iucnredlist.org
  2. Western Australia Department of Conservation and Land Management (September, 2002)
    http://www.environment.gov.au/biodiversity/threatened/publications/recovery/swamp-tortoise/index.html
  3. Ehmann, H. (1992) Encyclopedia of Australian Animals: Reptiles. Collins, Angus & Robertson, HarperCollins, Australia.
  4. Burbidge, A.A. and Kuchling, G. (1994) Western Swamp Tortoise Recovery Plan, Wildlife Management Program No 11. Department of Conservation and Land Management, Western Australia.
  5. Perth Zoo (September, 2002)
    http://www.perthzoo.wa.gov.au
  6. Burbidge, A.A. and Kuchling, G. (1997) Western swamp tortoise recovery plan, January 1998 - December 2002. 2nd edn. Department of Conservation and Land Management, Como, Western Australia.