349.

Kakadu Pebble Mouse

Pseudomys calabyi

French: Pseudomys de Calaby / German: Calaby-Australienmaus / Spanish: Raton de guijarros de Kakadu

Other common names: Calaby’s Mouse, Kakadu Pebble-mound Mouse, Kakadu Pebble-mound Pseudomys

Taxonomy. Pseudomys laborifex calabyi Kitchener & Humphreys, 1987,

Uranium Development Project Falls, Northern Territory, Australia.

Pseudomys calabyi was elevated to species status by A. K. Lee in 1995, this being followed in subsequent treatments. It forms a natural grouping with other pebble mice that may merit generic distinction from Pseudomys . Monotypic.

Distribution. Restricted to a small range

within the monsoon tropics of N Northern Territory, Australia, with almost all records from Kakadu and Litchfield National Parks.

Descriptive notes. Head-body 68-95 mm, tail 64-94 mm, ear 12-14 mm, hindfoot 16-19 mm; weight 12-20 g. A small mouse, without marked distinctive features in external morphology. The Kakadu Pebble Mouse is gray brown above, tinged rufous on flanks, and white below.

Habitat. Known only from tropical savanna woodlands and open forests, especially those dominated by Eucalyptus and Corymbia (both Myrtaceae). At finer scale, occurs mostly on hills and in environments with extensive ground cover of gravel, small stones, and pebbles.

Food and Feeding. Limited available information suggests that the Kakadu Pebble Mouse feeds mainly on seeds, especially of grass species.

Breeding. The Kakadu Pebble Mouse probably breeds repeatedly through much of the dry season (March—November).

Activity patterns. The Kakadu Pebble Mouse is terrestrial and nocturnal. It shelters during day in burrow systems, around which it constructs small mounds of pebbles. Individuals spend much time arranging collections of pebbles around burrow entrances, moving pebbles by carrying them in the mouth.

Movements, Home range and Social organization. Kakadu Pebble Mice are social, with many individuals using the same burrow systems.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Kakadu Pebble Mouse is not listed as threatened under Australian legislation. Status poorly resolved, but the available limited information suggests ongoing decline across its small range, even within conservation reserves. Estimated extent of occurrence is 23,000 km? and area of occupancy 128 km?®, but these values may somewhat understate true range, given limited survey across potential range. Declines probably due to current regime of frequent and extensive fire, and predation by feral cats.

Bibliography. Breed & Ford (2007), Ford (2006), Ford & Johnson (2007), Jackson & Groves (2015), Kitchener & Humphreys (1987), Lee (1995), Russell-Smith et al. (2014), Van Dyck& Strahan (2008), Woinarski (1992), Woinarski, Armstrong et al. (2010), Woinarski, Burbidge & Harrison (2014), Woinarski, Legge et al. (2011), Ziembicki (2015).