367.

Central Australian Rock Rat

Zyzomys pedunculatus

French: Zyzomys pédonculé / German: Zentralaustralische Dickschwanzratte / Spanish: Rata de roca de Australia central

Other common names: Central Rock Rat, Macdonnell Range Rock Rat

Taxonomy. Conilurus pedunculatus Waite, 1896,

Alice Springs, Northern Territory, Australia.

Transferred to genus Laomys by H. A. Longman in 1916, the taxon pedunculatus was moved to Zyzomys by J. A. Mahoney and B. J. Richardson in 1988, with latter treatment accepted byall subsequent authors. Monotypic.

Distribution. Australia. Current known distribution is restricted to a few summit and

ridge areas mostly in the Chewings and Heavitree ranges between Ormiston Pound and Ellery Creek, and Mt Edward and Mt Sonder within theW MacDonnell Ranges.

Descriptive notes. Head-body 108-140 mm, tail 110-140 mm, ear 20-23 mm, hindfoot 25-29 mm; weight 70-150 g. The Central Australian Rock Rat has large prominent eyes, long vibrissae, and a tail that is often markedly thickened (with stored fat) at base, lightly furred, and with hairs becoming longer toward tail tip. Part or all of the tail is often missing (presumably shed as a response to attempted predation). Body fur is yellowish brown above, and cream to white on belly.

Habitat. Restricted to rugged rocky areas, and now known only from mountain summits and quartzite ridge tops. Occurs mostly in hummock grasslands and heathlands, including areas long unburnt and recently burnt. Historically, and up to the early 2000s,this species’ distribution, abundance, and habitat range expanded during and immediately following good rainfall years.

Food and Feeding. Central Australian Rock Rats are mostly granivorous, taking seeds from a range of woody shrubs and grasses, including from some plant species that typically become more abundant after recent fire, and hummock grasses of genus Triodia (Poaceae) that seed most abundantly after long periods without fire. They also consume someleaf material and, in drier periods (when seed is less available), some plant stem material; invertebrates are taken occasionally.

Breeding. In high rainfall years, breeding may occur throughout year. In captivity,litter size is 1-4 and sexual maturity is reached at 8-10 months.

Activity patterns. The Central Australian Rock Rat is terrestrial and nocturnal.

Movements, Home range and Social organization. The Central Australian Rock Rat is probably largely sedentary. It now occurs in a small set of isolated and small subpopulations. Populations may increase substantially in and immediately after periods of high rainfall, but then decline severely in lower-rainfall years and after extensive wildfire.

Status and Conservation. CITES Appendix I. Classified as Critically Endangered on The IUCN Red List, on basis of its very small range, few locations, and ongoing decline. Also listed as endangered under Australian legislation. The species’ current area of occupancy may be less than 200 ha and its extent of occurrence less than 1000 km?, It has suffered a catastrophic decline over the last ¢.200 years, having formerly had a patchy distribution (based on relatively few live-trapped specimens and subfossils) that encompassed rocky range areas across much of central Australia and extending to Cape Range in coastal mid-Western Australia. Population is thought to number fewer than 1000 mature individuals, and declining. Historic and ongoing decline probably due mostly to predation by feral cats. May be adversely affected also by extensive wildfire, its preferred fire regime being one that maintains a mosaic of areas that have been recently burnt and long unburnt.

Bibliography. Baynes & Jones (1993), Cole & Woinarski (2002), Edwards (2013a, 2013b), Longman (1916), Mahoney & Richardson (1988), McDonald, Brittingham et al. (2015), McDonald, Griffiths et al. (2015), McDonald, Pavey et al. (2013), McDonald, Stewart et al. (2016), McDonald, Ward et al. (2017), Nano et al. (2003), Parker (1973), Van Dyck & Strahan (2008), Watts & Aslin (1981), Woinarski et al. (2014).