The western swamp turtle or western swamp tortoise (''Pseudemydura umbrina'') is a critically endangered species of freshwater

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to a small portion of

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. It is the only member of the genus ''Pseudemydura'' in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

subfamily Pseudemydurinae. It is the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to the subfamily

Chelodininae 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 Ame ...

. As a consequence of the greatly altered habitat in the area in which it occurs near

Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth is ...

, Western Australia, it exists in small fragmented populations, making the species critically endangered.

Taxonomy

The accepted description of the species by

Friedrich Siebenrock Friedrich Siebenrock (20 January 1853, Schörfling am Attersee – 28 January 1925, Vienna) was an Austrian herpetologist. Biography He studied zoology at the Universities of Innsbruck and Vienna, afterwards serving as a demonstrator under ...

was published in 1901. The first specimen of the western swamp tortoise was collected by

Ludwig Preiss Johann August Ludwig Preiss (21 November 1811 – 21 May 1883) was a German-born British botanist and zoologist. Early life Preiss was born in Herzberg am Harz. He obtained a doctorate, probably at Hamburg, then emigrated to Western Australia. ...

in 1839 and sent to Vienna Museum. There it was labelled "New Holland" and was named ''Pseudemydura umbrina'' 1901 by Seibenrock. No further specimens were found until 1953. In 1954, Ludwig Glauert named these specimens ''Emydura inspectata'', but in 1958, Ernest Williams of

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

showed that to be a synonym of ''Pseudemydura umbrina''.

Description

Adult males do not exceed a length of 155 mm or a weight of 550 g. Females are smaller, not growing beyond 135 mm in carapace length or a weight of 410 g. Hatchlings have a carapace length of 24–29 mm and weigh between 3.2 and 6.6 g. The colour of the western swamp turtle varies dependent on age and the environment where it is found. Typical colouration for hatchlings is grey above with bright cream and black below. The colour of adults varies with differing swamp conditions, and varies from medium yellow-brown in clay swamps to almost black with a maroon tinge in the black coffee-coloured water of sandy swamps. Plastron colour is variable, from yellow to brown or occasionally black; often there are black spots on a yellow background with black edges to the

scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...

s. The legs are short and covered in scale-like scutes and the feet have well-developed claws. The short neck is covered with horny

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

s and on the top of the head is a large single scute. It is the smallest chelid found in Australia. The only other species of freshwater turtle occurring in the southwest of Western Australia is the

southwestern snake-necked turtle The oblong turtle (''Chelodina oblonga''), also known commonly as the narrow-breasted snake-necked turtle and the southwestern snake-necked turtle, is a species of turtle in the family Chelidae. The species is endemic to the southwestern part o ...

(''Chelodina oblonga''). It has a neck equal to or longer than its shell, making the two species from south west

easily distinguishable.

Distribution

The western swamp turtle has been recorded only in scattered localities on the

Swan Coastal Plain The Swan Coastal Plain in Western Australia is the geographic feature which contains the Swan River as it travels west to the Indian Ocean. The coastal plain continues well beyond the boundaries of the Swan River and its tributaries, as a geol ...

in Western Australia, from

Perth Airport Perth Airport is an international, domestic and general aviation airport serving Perth, the capital city of Western Australia. It is the fourth busiest airport in Australia measured by passenger movements and falls within the boundaries of ...

northwards to near Pearce Royal Australian Air Force Base in the Bullsbrook locality (roughly parallel with the

Darling Scarp The Darling Scarp, also referred to as the Darling Range or Darling Ranges, is a low escarpment running north–south to the east of the Swan Coastal Plain and Perth, Western Australia. The escarpment extends generally north of Bindoon, to th ...

). Most of this area is now cleared and either

urbanised Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly the ...

, used for

intensive agriculture Intensive agriculture, also known as intensive farming (as opposed to extensive farming), conventional, or industrial agriculture, is a type of agriculture, both of crop plants and of animals, with higher levels of input and output per unit of ag ...

or mined for clay for brick manufacture.

Conservation

The legal status of the species as listed by the Australian federal and state ( W.A.) governments is critically endangered. The IUCN Red List assessed the species as Critically Endangered. The 2007 Red List noted the description as in need of updating. A recovery plan was first published in 1994 and has been updated since, the most recent version is dated 2010. Threatening processes include small, fragmented populations occurring in nature reserves that are smaller than an individual's home range, predation by the introduced red fox ''

Vulpes vulpes The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe and Asia, plus ...

'', changed hydrology due to land-use changes and extraction of groundwater, and reducing rainfall due to climate change. Recovery actions include population monitoring, management of nature reserves, and captive breeding at Perth Zoo and subsequent reintroduction and introduction. This species is notable in conservation history for being the first example of an endangered vertebrate that is being translocated to a distant location (200 kilometers poleward) expressly because of climate change. Public appreciation and assistance is supported by The Friends of the Western Swamp Tortoise.

References

External links

Images at ARKive.org
{{Testudines Reptiles of Western Australia Critically endangered fauna of Australia Pseudemydura Reptiles described in 1901 Turtles of Australia Endemic fauna of Southwest Australia