Western Swamp Tortoise
Encyclopedia
The western swamp tortoise (Pseudemydura umbrina), also known as the western swamp turtle, is a short-necked freshwater tortoise that monotypically represents the sub-family Pseudemydurinae.
The colour of the western swamp tortoise varies dependent on age and the environment where it is found. Typical coloration 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
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
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 tortoise occurring in the southwest of Western Australia is the Oblong or long-necked tortoise
(Chelodina oblonga). It has a neck equal to or longer than its shell, making the two species easily identifiable.
The first specimen of the western swamp tortoise was collected by Ludwig Preiss
in 1839 and sent to Vienna Museum. There it was labelled New Holland and was named Pseudemydura umbrina 1901 by Seibenrock. No further collection of specimens was recorded until 1953. Glauert in 1954 named these specimens Emydura inspectata but in 1958 Ernest Williams of Harvard University
showed them to be synonyms of P. umbrina, collected by Preiss..
in Western Australia
, from Perth Airport
to near Pearce Royal Australian Air Force Base
in the Bullsbrook
locality. (roughly parallel with the Darling Scarp
). Most of this area is now cleared and either urbanised or used for intensive agriculture.
Threatening factors to population and habitat were assessed as making this species vulnerable to extinction, and described as Critically Endangered
on the 1996 IUCN Red List
. The 2007 Red List notes this as outdated, and the conservation status requires reassessment.
Description
Adult males do not exceed a length of 155mm or a weight of 550g. Females are smaller, not growing beyond 135mm carapace length or a weight of 410g. Hatchlings have a carapace length of 24-29mm and weigh between 3.2 and 6.6g.The colour of the western swamp tortoise varies dependent on age and the environment where it is found. Typical coloration 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
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
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
Tubercle
A tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to....
s and on the top of the head is a large single scute. It is the smallest chelid
Chelidae
The Chelidae are one of the three living families of the turtle suborder Pleurodira and are commonly called the 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...
found in Australia.
The only other species of freshwater tortoise occurring in the southwest of Western Australia is the Oblong or long-necked tortoise
Narrow-breasted Snake-necked Turtle
The narrow-breasted snake-necked turtle or long necked tortoise is a species of turtle in the Chelidae family.It is endemic to the southwestern part of Western Australia....
(Chelodina oblonga). It has a neck equal to or longer than its shell, making the two species easily identifiable.
The first specimen of the western swamp tortoise was collected by Ludwig Preiss
Ludwig Preiss
Johann August Ludwig Preiss was a German-born British botanist and zoologist.Preiss was born in Herzberg am Harz, Germany. 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 collection of specimens was recorded until 1953. Glauert in 1954 named these specimens Emydura inspectata but in 1958 Ernest Williams of Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
showed them to be synonyms of P. umbrina, collected by Preiss..
Distribution
The western swamp tortoise has been recorded only in scattered areas on the Swan Coastal PlainSwan 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 geological and biological zone, one of Western Australia's...
in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
, from Perth Airport
Perth Airport
Perth Airport is an Australian domestic and international airport serving Perth, the capital and largest city of Western Australia. The airport itself is located in the suburb of Perth Airport....
to near Pearce Royal Australian Air Force Base
RAAF Base Pearce
RAAF Base Pearce is the main RAAF base in Western Australia. The base is located in Bullsbrook, north of Perth. It is used for training by the Royal Australian Air Force and the Republic of Singapore Air Force...
in the Bullsbrook
Bullsbrook, Western Australia
Bullsbrook is a suburb of Perth, Western Australia in the outer metropolitan area. It is located with the City of Swan. The original Bullsbrook townsite is located slightly west of the current town, on the 17 km mark of the Midland Railway...
locality. (roughly parallel with the Darling Scarp
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...
). Most of this area is now cleared and either urbanised or used for intensive agriculture.
Threatening factors to population and habitat were assessed as making this species vulnerable to extinction, and described as Critically Endangered
Critically Endangered
Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species' numbers have decreased, or will decrease, by 80% within three generations....
on the 1996 IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. The 2007 Red List notes this as outdated, and the conservation status requires reassessment.