The colour of the mouse's pelt is buff brown, darker to blackish at the head. The paws are white beneath and buff above, The underparts are white, up to the throat and mouth. The species resembles the related P. hermannburgensis, the morphology is distinguished by smaller ears, feet and tail. The feet do not exceed 16 millimetres in length.
It is native to and found only in Western Australia, where it lives in pebbly soils in arid tussock grassland and acacia woodland. Like other pebble-mound mice, the western pebble-mound mouse creates its own microhabitat by scattering a mound of pebbles around its burrows. The air temperature around the pebbles warms up faster in the morning than the pebbles themselves, causing the formation of small droplets of dew by condensation.
The vegetation at the preferred habitat, hummock grasslands, is Triodia basedowii, Cassia. Acacia and Ptilotus, and it is associated with eroding sands at natural features which expose small stones (pebbles). The species at the type location were the spinifex Triodia basedowii and T. pungens, Acacia aneura, and Cassia desolata and C. helmsii, these cassias intermittently occur with Eucalyptus gamophylla and E. oleosa at the surrounding gibber plain.
The species occurs as disjunct populations within its range. The range is subject to changes in land use resulting in loss of habitat, and noted as contracting.
According to the 2008 IUCN Red List of Threatened Species, the species is restricted to the non-coastal, central and eastern parts of the Pilbara, Western Australia. It was formerly more widespread.
