Notoryctes caurinus
States and territories: North-western Western Australia and possibly far western Northern Territory in the western Tanami Desert area.
Regions: This species has been found in the Great Sandy, Little Sandy and Gibson Deserts of north-western Western Australia (Langford & Pavey 2002, Benshemesh and Aplin 2008).
Habitat: Sandy desert regions, underground signs are most common on well vegetated dunes (Benshemesh 2004).
Habit: Mostly underground, about 20 to 60 cm below the ground surface, moving about by digging back-filled tunnels in search of prey (Benshemesh 2008).
Avg. body weight: As for the southern marsupial mole, body weight range 40–70 g (Benshemesh & Aplin 2008).
Activity pattern: Unknown.
Diet: Unknown, but suspected to be similar to the southern marsupial mole.
Breeding: Unknown, but may be similar to the southern marsupial mole.
Description
The marsupial moles have specialised adaptations that have evolved in response to the species' burrowing lifestyle (Langford & Pavey, 2002). Their eyes are vestigial and hidden under the skin, their ears are reduced to a simple opening beneath the fur on either side of the head, and their conical shaped noses are covered with a tough, horny shield to protect against the sand. To burrow through the sand, the third and fourth digits of the forefoot are enlarged and possess large shovel-like claws for digging. They have a short, hard and leathery tail that is marked by distinct rings, ending in a horny ‘knob’. The colouration of the fur can vary from near white through pinkish to rich golden red.
Given the similarity in appearance between southern and northern marsupial moles and the lack of reported information about the species’ biology, discerning the ranges of the two marsupial mole species is difficult. Recent work suggests that the edges of the distributions of the two species exists somewhere in the Tanami Desert, with the southern marsupial mole occurring in the east and the northern marsupial mole in the western Tanami, but it remains uncertain whether these forms are sympatric (Benshemesh 2004).
Survey methods
The most efficient method of surveying for marsupial moles is to count the number of tunnels underground (Benshemesh 2005). A summary of the technique is provided below, and detailed in Section 3.2.7 (note that the surveyor should consult J Benshemesh for advice prior to conducting any surveys):
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survey trenches should be dug approximately 80 centimetres deep, 120 centimetres long and 40 centimetres wide
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the trench should be dug with caution, and the use of mechanical equipment should be avoided
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digging should cease if marsupial moles are observed
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trenches should be allowed to dry for between three to five days (few tunnels will be apparent until the soil is adequately dry)
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the tunnels will appear as circular or oval shapes, usually larger than 25 millimetres but depending on the angle made with the trench wall
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trenches should be dug at three levels on the dune: near the crest, mid slope, and at the base of the dune, positioned less than 1 km apart
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in suitable habitat two to six tunnels are usually found per square metre of vertical trench face.
Valuable information can also be obtained recording tracks, and photographs should be taken for confirmation by an expert, particularly in areas of uncertainty between the known ranges of the two species (Benshemesh 2004).
Other techniques that could be employed in areas up to 5 hectares in size, but are less reliable and efficient, include:
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daytime searches for potentially suitable habitat resources, such as sandy soil in the central desert regions (description of technique and recommended effort outlined in Section 3.1)
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early morning (that is, before the sun is too high, making tracks hard to discern, and before a breeze disturbs track definition) searches for signs of activity, particularly for tracks (photographs should be taken for confirmation by an expert) or individuals that may be observed on the surface following rain or during cold weather (description of technique and recommended effort outlined in Section 3.2). Any person undertaking track searches need to have experience at tracking and identifying small mammal track signs in arid desert country
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collection of predator scats, owl casts or remains, targeting predatory bird and mammal nests and dens (description of technique and effort outlined in Section 3.2.3). Marsupial moles can be identified to genus from hair samples (see Table 2, Section 3.3.7), or to species if genetic techniques are used.
Similar species in range
The taxonomy of the Notoryctes is unclear, with a suggestion that there may be one or more currently undescribed species. Currently two species of marsupial moles are recognised: the southern marsupial mole Notoryctes typhlops and the northern marsupial mole Notoryctes caurinus. The two species are thought to have an overlap in distribution; however, this has not currently been demonstrated. Although the two species can be separated genetically, they are difficult to separate morphologically. Characters used include the slightly smaller size, the narrower and shorter snout, the lack of anterior molars and the remaining cheek teeth are smaller and simpler in structure in northern marsupial moles (Benshemesh 2008, Benshemesh & Aplin 2008). In addition, the tracks have been reported to be distinct between the two species (Benshemesh & Aplin 2008). Langford and Pavey (2002), in their description of the southern marsupial mole, refer to ‘morphometric and dental studies’ as the basis for the separation of the southern marsupial mole from the Great Sandy and Gibson Deserts from the northern species. Since distinguishing the species in the field may not be possible, identification is likely to require a hair sample, provided that the appropriate permission and licensing has been granted by the relevant state or territory government organisations.
Benshemesh, J. 2004. Recovery Plan for Marsupial Moles Notoryctes typhlops and N. caurinus. 2005 – 2010. Northern Territory Department of Infrastructure, Planning and Environment, Alice Springs.
Benshemesh, J. 2005. Manual for Marsupial Mole survey and Monitoring by Trenches, Version 1.0. Report to Anangu-Pitjantjatjara Land Management and the Department of Heritage and Environment (SA).
Benshemesh, J. and Aplin, K.P. 2008. Kakarratul Notoryctes caurinus. In ‘The Mammals of Australia’ (Eds. S. Van Dyck and R. Strahan) pp. 410 – 412 (Reed New Holland: Sydney).
Langford, D. and Pavey, C. 2002. Threatened species of the Northern Territory - Southern Marsupial Mole Notoryctes typhlops. Available from: www.nt.gov.au/nreta/wildlife/animals/threatened/pdf/mammals. Accessed 2010-03-22 T11:45:45.
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