Notomys alexis Thomas 1922

339.

Spinifex Hopping Mouse

Notomys alexis

French: Notomys alexis / German: Spinifex-Australienhiipfmaus / Spanish: Raton saltador de spinifex

Other common names: Spinefex Hopping Mouse

Taxonomy. Notomys alexis Thomas, 1922,

“35 miles [= 56 km] S. W. of Alroy [Northern Territory, Australia], about 135° 40” E. and 19° 30’ S. Alt. 800° [= 244 m].”

Subspecies exhibit minor morphological differences, and their geographic bounds are not well resolved. Three subspecies currently recognized.

Subspecies and Distribution. N. a. alexis Thomas, 1922 — inland Western Australia and Northern Territory.

N.a.everardensisFinlayson,1940—inlandSouthAustralia.

N. a. reginae Troughton, 1936 — SW Queensland.

Descriptive notes. Head—body 90-115 mm, tail 115-150 mm, ear 21-26 mm, hindfoot 32-36 mm; weight 27-50 g. The Spinifex Hopping Mousehas body form typical of hopping mice, with very long hindfeet, long tail, and large eyes. Tail has brush tip of elongate hairs, although this less pronounced than on most other hopping mice. Pelage is light brown to chestnut above, and gray white below. Both sexes have a throat pouch.

Habitat. Mostly associated with sandy soils, including sand dunes and plains, and typically in areas of hummock grasslands (7riodia [Poaceae] species: “spinifex”), or open woodlands with hummock grass understory. At times of population irruption, the Spinifex Hopping Mouse may occur in a broader range of habitats, including on loamy and (occasionally) clay soils with tussock grasslands. In at least some areas,it prefers more open sites, such as those exposed to recentfire.

Food and Feeding. The Spinifex Hopping Mouse is omnivorous, with seeds and invertebrates typically important food items, but diet also includes other plant material (flowers, stems, foliage, and roots), and fungi. Invertebrates typically comprise a higher proportion of diet than is the case for other hopping mice.

Breeding. The Spinifex Hopping Mouse is an opportunistic breeder, with substantial reproductive output, and almost continuous breeding following periods of good rainfall. Litter sizes vary substantially (1-9 reported in captive colonies), but most common litter size is four. Gestation lasts 32-34 days for non-lactating females, extending to 40 daysif lactating. Females can give birth when ¢.85 days old.

Activity patterns. Spinifex Hopping Mice are nocturnal, sheltering during the day in deep burrow systems. They are terrestrial.

Movements, Home range and Social organization. Social groups may maintain and use several burrows. Spinifex Hopping Mice population undergoes marked fluctuations (“boom-bust”), with increases following periods of above-average rainfall in inland Australia. Social, groups of up to ten individuals communally inhabiting a burrow system. Many individuals may be transient, and capable of dispersal over 10 km or more. A radio-study of a small number of individuals reported longest movement of 2-7 km, and overnight movement of 700 m.

Status and Conservation. Classified as Least Concern on The IUCN Red List. At some sites, commonly recorded in diet of introduced Red Fox (Vulpes vulpes) and feral cats; however, no evidence of broad-scale decline in distribution or ongoing decline in population size.

Bibliography. Dickman, Mahon et al. (1999), Dickman, Wardle et al. (2014), Finlayson (1940), Jackson & Groves (2015), Letnic (2002), Masters (1993), Murray et al. (1999), Paltridge (2002), Thomas (1922b), Troughton (1936c¢), Van Dyck & Strahan (2008), Watts & Aslin (1981).