Southern marsupial mole
Southern marsupial mole[1] | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Infraclass: | Marsupialia |
Order: | Notoryctemorphia |
Family: | Notoryctidae |
Genus: | Notoryctes |
Species: | N. typhlops
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Binomial name | |
Notoryctes typhlops Stirling, 1889.
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Southern marsupial mole range |
The southern marsupial mole (Notoryctes typhlops), also known as the itjaritjari (pronounced [ˈɪɟɐrɪɟɐrɪ]) or itjari-itjari,[3][4] is a mole-like marsupial found in the western central deserts of Australia. It is extremely adapted to a burrowing way of life. It has large, shovel-like forepaws and silky fur, which helps it move easily. It also lacks complete eyes as it has little need for them. It feeds on earthworms and larvae.[5]
History of discovery
Although the southern marsupial mole was probably known by
Nineteenth century scientists believed that marsupials and eutherians had evolved from the same primitive ancestor and were looking for a living specimen that would serve as the missing link. Because the marsupial mole closely resembled the golden moles of Africa, some scientists concluded that the two were related and that they had found the proof. This, however, is not the case, as became obvious by examining better-preserved specimens that had a marsupial pouch.[7] The striking similarities of the two species are, in fact, the result of convergent evolution.
Taxonomy and phylogeny
Although the family
Due to their highly specialized morphology and the fact that notoryctids share many common characteristics with other marsupials, there has been much debate surrounding their
Furthermore, molecular data suggests that Notoryctemorphia separated from other marsupials around 64 million years ago.
Morphology
The southern marsupial mole is small in size, with a head and body length varying from 121 to 159 mm, a tail length of 21–26 mm and a weight of 40-70 g. The body is covered with short, dense, silky fur with a pale cream to white color often tinted by the iron oxides from the soil which gives it a reddish chestnut brown tint. It has a light brownish pink nose and mouth and no
The cone shaped head merges directly with the body, and there is no obvious neck region. The limbs are short and powerful, and digits III and IV of the manus have large spade-like claws. The dentition varies with individuals and, because the molars have a root of only one third of the length, it has been assumed that moles cannot deal with hard food substances.[6] The dorsal surface of the rostrum and the back of the tail have no fur and the skin is heavily keratinized. There is no external evidence of the eyes, and the optic nerve is absent. It does, however, have a pigment layer where the eyes should be, probably a vestige of the retina. Both lachrymal glands and
The external ear openings are covered with fur and do not have a
Adaptations
In an example of
Habitat and distribution
The habitat of the southern marsupial mole is not well known, and is generally based on scattered records. It has been often recorded in sandy dunes or flats, usually where
Behavior
Due to the lack of any field studies regarding the marsupial moles, there is little known about their behavior. Observations of captive animals are limited since most of the moles do not survive much longer than a month after capture.
Surface behavior
It sometimes wanders above the surface where traces of several animals have been found. While most evidence indicates that it does this seldom and moves just a few meters before burrowing back underground, on some occasions multiple tracks were found suggesting that one or more animals have moved above ground for several hours. According to Aboriginal sources, marsupial moles may surface at any time of day, but seem to prefer to do so after rain and in the cooler season.[6]
Captive animals have been observed to feed above ground and then return underground to sleep. Occasionally it has been recorded to suddenly "faint" on the surface without waking up for several hours until disturbed.[16]
Above the ground it moves in a sinuous fashion, using its powerful forelimbs to haul the body over the surface and its hind limbs to push forward. The forelimbs are extended forward in unison with the opposite hind limb. Moles move about the surface with frantic haste but little speed, as one observer once likened it to a "Volkswagen Beetle heaving its way through the sand".[7]
Burrowing behavior
While burrowing, the southern marsupial mole does not make permanent tunnels, but the sand caves in and tunnels back-fill as the animal moves along. For this reason its burrowing style has been compared to "swimming through the sand”". The only way its tunnels can be identified is as a small oval shape of loose sand. Although it spends most of its active time 20-100 cm below the surface, tunneling horizontally or at shallow angles, it sometimes for no apparent reason turns suddenly and burrows vertically to depths of up to 2.5 meters.[17]
Although most food sources are likely to occur at depths of approximately 50 cm from the surface, the temperature of these environments varies greatly from less than 15°C during winter to over 35°C during summer. While one of the captive moles was observed shivering when the temperature dropped under 16°C, it seems probable that moles can select the temperature of their environment by burrowing at different depths.[6]
Diet
Little is known about the southern marsupial mole's diet, and all information is based on the gut content of preserved animals and on observations made on captive specimens. All evidence seems to suggest that the mole is mainly insectivorous, preferring insect eggs, larvae and pupae to the adults.[18] Based on observations made on captive animals, it seems that one of the favorite food choices was beetle larvae, especially Scarabaeidae.[16] Because burrowing requires high energy expenditure it seems unlikely that the mole searches for its food in this prey impoverished environment, and suggests that it probably feeds within nests. It has been also recorded to eat adult insects, seeds and lizards. Below the desert sands of Australia, the marsupial mole searches for burrowing insects and small reptiles. Instead of building a tunnel, it "swims" through the ground, allowing the sand to collapse behind it.[6]
Social behavior
There is little known about the social and reproductive behavior of these animals, but all evidence seems to suggest that it leads a solitary life. There are no traces of large burrows where more than one individual might meet and communicate. Although it is not known how the male locates the female, it is assumed that they do so using their highly developed olfactory sense.[13]
The fact that the middle ear seems to be morphologically suited for capturing low frequency sounds, and that moles produce high pitched vocalizations when handled, indicates that this kind of sound that propagates more easily underground may be used as a form of communication.[6]
Human interactions
The southern marsupial mole was known for thousands of years to Australia’s Indigenous people and was part of their mythology. It was associated with certain sites and dreaming trails such as Uluru and the Anangu-Pitjantjatjara Lands. They were regarded with sympathy, probably due to its harmless nature, and were only eaten during hard times. Aboriginal people have good tracking skills and generally cooperate with researchers in teaching them these skills and help finding specimens. Their involvement is instrumental in gathering information about the species’ habitat and behavior.[6]
Historical records suggest that the southern marsupial mole was relatively common in the late 19th century and early 20th century. There was a large trade in marsupial mole skins in the Finke River region between 1900 and 1920. Large numbers of aborigines arrived at the trading post with 5-6 pelts each for sale to trade for food and other commodities. It is estimated that hundreds to several thousand skins were traded at these meetings, and that at the time the mole was relatively common.[7]
Conservation status
So little is known about the southern marsupial mole that it is difficult to assess its exact distribution and how it varied over the last decades. However circumstantial evidence suggests that their numbers are dwindling. Although the decreasing acquisition rate is difficult to interpret due to the chance nature of the findings, there are reasons for concern. About 90% of medium-sized marsupials in arid Australia have become threatened due to cat and fox predation. A recent study indicates that remains of marsupial moles have been found in 5% of the cats and foxes faecal pellets examined.[19] Moles are also sensitive to changes in the availability of their food caused by changing fire regimes and the impact of herbivores. The southern marsupial mole is currently listed as endangered by the IUCN.[2] Efforts to protect this species focus on advocating for maintaining a healthy population of moles to better understand their biology and behavior, and for conducting field studies to monitor the species distribution and abundance with the help of Aborigines.[6]
References
- OCLC 62265494.
- ^ . Retrieved 13 November 2021.
- ^ "Southern Marsupial Mole (Notoryctes typhlops)". Threatened species & ecological communities. Australian Government Department of the Environment and Energy. Retrieved 18 February 2019.
- ^ "Notoryctes typhlops — Itjaritjari, Southern Marsupial Mole, Yitjarritjarri". Species Profile and Threats Database. Australian Government Department of the Environment and Energy. Retrieved 18 February 2019.
- ^ Whitfield, Philip (1998). The Simon & Schuster Encyclopedia of Animals. New York: Marshall Editions Development Limited. p. 25.
- ^ ISBN 9780643066342.
- ^ a b c d Johnson, Ken (1991). "The mole who comes from the sun". Wildlife Australia. Spring: 8–9.
- ^ Gott, M. (1988). "A Tertiary marsupial mole (Marsupialia: Notoryctidae) from Riversleigh, northeastern Australia and its bearings on notoryctemorphian phylogenetics". Honours Thesis, University of Sydney, NSW.
- PMID 4447497.
- .
- doi:10.1071/ZO96030.)
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: CS1 maint: multiple names: authors list (link - ^ a b Thompson, Graham (2000). "Blind Diggers in the Desert". Nature Australia. 26: 26–31.
- ^ a b c Johnson, Ken; Walton, Dan (1987). D.W. Walton (ed.). Fauna of Australia v 1B Mammalia. Canberra: Australian Government Publishing Service. pp. 591–603.
- ^ "Facts Sheet - Southern Marsupial Mole". Department of the Environment, Water, Heritage and the Arts. Retrieved 2009-05-01.
- doi:10.1071/AM00115.
- ^ S2CID 254727412.
- ^ K.A. Johnson (1998). Ronald Strahan (ed.). The mammals of Australia. Sydney: New Holland Publishers Pty Ltd. pp. 409–11.
- S2CID 254709786.
- doi:10.1071/AM98427.