The brush-tailed rabbit rat (''Conilurus penicillatus'') is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

in the family

Muridae The Muridae, or murids, are the largest family of rodents and of mammals, containing approximately 1,383 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia. The name Muridae come ...

. It is found in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and

Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

Taxonomy

The brush-tailed rabbit-rat is one of three ''Conilurus'' species that were extant in Australia prior to European colonisation, and represents the sole surviving species of the genus. Two other species, the white-footed rabbit-rat (''C. albipes'') and the Capricorn rabbit-rat (''C. capricornensis''), are now extinct. Morphological analysis established three subspecies of ''C. penicillatus'', of which one is on Papua New Guinea and two are present within Australia: one on the

Tiwi Islands The Tiwi Islands ( tiw, Ratuati Irara meaning "two islands") are part of the Northern Territory, Australia, to the north of Darwin adjoining the Timor Sea. They comprise Melville Island, Bathurst Island, and nine smaller uninhabited islands, wi ...

off the coast of the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

, and another on the Australian mainland.

Description

The brush-tailed-rabbit-rat is a moderately sized murid rodent, weighing from 116 to 216 g with a head-body length of 135 to 227 mm and a tail length of 102 to 235 mm. Typically individuals are coloured grizzled grey or brown on the upper side of the body, and white to cream coloured on the belly. The long tail ends in a slight brush structure with either a black or white tail tip.

Behaviour

The brush-tailed rabbit-rat is a semi-arboreal, nocturnal species that spends some of its time foraging on the ground. Individuals tend to den in trees such as ''

Eucalyptus miniata ''Eucalyptus miniata'', commonly known as the Darwin woollybutt or woolewoorrng, is a species of medium-sized to tall tree that is endemic to northern Australia. It has rough, fibrous, brownish bark on the trunk, smooth greyish bark above. Adult ...

'' and ''

Eucalyptus tetrodonta ''Eucalyptus tetrodonta'', commonly known as Darwin stringybark or messmate, is a species of medium-sized to tall tree that is endemic to northern Australia. It has rough, stringy or fibrous bark on the trunk and branches, lance-shaped leave ...

'', as well as hollow logs on the ground. The species makes use of smaller hollows and hollows that are closer to the ground, than other co-occurring and larger-bodied mammal species such as the

common brushtail possum The common brushtail possum (''Trichosurus vulpecula'', from the Greek for "furry tailed" and the Latin for "little fox", previously in the genus ''Phalangista'') is a nocturnal, semiarboreal marsupial of the family Phalangeridae, native to Austr ...

(''Trichosurus vulpeculus'') and the

black-footed tree-rat The black-footed tree-rat (''Mesembriomys gouldii''), also known as Djintamoonga, is one of two endemic (ecology), endemic Australian rodent species in the genus ''Mesembriomys.'' Both the black-footed tree-rat and its congener, the golden-backe ...

(''Mesembriomys gouldii''). This may make the brush-tailed rabbit-rat more susceptible to predation and destruction by high-intensity savanna fires than these species.

Distribution and decline

The brush-tailed rabbit-rat has a small, poorly known distribution in Papua New Guinea, and a larger distribution within Australia. The species was formerly much more common and widespread than it is currently. On the Australian mainland, the species has substantially declined, with a study in the Northern Territory finding that its extent of occurrence has declined by more than 65%. The same study found that the species is contracting towards geographic areas that are wetter and lower than where it was found historically. Population declines are not limited to the mainland, with one study finding a 64% reduction in trapping success on the Tiwi Islands between the year 2002 and 2015. The species has very few contemporary records from the Western Australian portion of the species distribution, but was formerly known from the Mitchell Plateau region of the Kimberley, with sparse records from other areas (e.g

Prince Regent National Park Prince Regent National Park, formerly the Prince Regent Nature Reserve, is a protected area in the Kimberley region of Western Australia. In 1978 the area was nominated as a UNESCO World Biosphere Reserve. Land The national park covers a tot ...

). In the Northern Territory, there have been no mainland records from outside of the

Cobourg Peninsula The Cobourg Peninsula is located east of Darwin in the Northern Territory, Australia. It is deeply indented with coves and bays, covers a land area of about , and is virtually uninhabited with a population ranging from about 20 to 30 in five ...

in more than ten years. The species was reintroduced to the Darwin region, however this reintroduction attempt failed and the species is also considered extirpated from

Kakadu National Park Kakadu National Park is a protected area in the Northern Territory of Australia, southeast of Darwin. It is a World Heritage Site. Kakadu is also gazetted as a locality, covering the same area as the national park, with 313 people recorded liv ...

(where many vertebrate species have declined despite the 'protected' status of the region). Population genomic analysis of the two Australian subspecies found high levels of differentiation among populations, including between the Tiwi Islands of Bathurst and Melville. The same study showed a substantial reduction in relatedness among individuals over 5 km distances, although significant values of spatial autocorrelation of genotypes persisted for distances of more than 100 km. This suggests that individuals tend to disperse much smaller distances than the co-occurring northern quoll (''Dasyurus hallucatus''), for which significant spatial autocorrelation exists at 500 km. Genetic diversity of the brush-tailed rabbit-rat was found to be highest on Melville Island, followed by Cobourg Peninsula, and lowest on Bathurst Island and at the Mitchell Plateau.

References

Conilurus Mammals of the Northern Territory Mammals of Western Australia Rodents of Australia Mammals described in 1842 Taxonomy articles created by Polbot Rodents of New Guinea {{WesternAustralia-stub