338.

Golden-backed Tree Rat

Mesembriomys macrurus

French: Rat 4 dos roux / German: Goldriicken-Baumratte / Spanish: Rata arboricola de dorso dorado

Other common names: Golden-backed Mesembriomys

Taxonomy. Hapalotis macrura Peters, 1876,

Mermaid Strait, Western Australia, Australia.

Hapalotis bower, described (from Derby, Western Australia) by E. P. Ramsay in 1887, was synonymized with M. macrurus in 1934 by T. Iredale and E. L.G. Troughton, who also recognized the species within Mesembriomys . Monotypic.

Distribution. Formerly widespread across NW Australia, but now confined to rugged areas of the N Kimberley region, Western Australia, and the islands of Augustus, Carlia, Chambers, Cockatoo, Conilurus, Hidden, Jar, Lachlan, Uwins, Wargul Wargul, and Wollaston, off the Kimberley mainland.

Descriptive notes. Head-body 188-245 mm, tail 290-360 mm, ear 23-26 mm, hindfoot 48-52 mm; weight 205-330 g. The Golden-backed Tree Ratis a large and distinctive species of arboreal rat with aslender body, long head and rostrum, and long, shaggy fur. It is much smaller than its closest relative, the Black-footed Tree Rat(M. goudlii). Dorsal pelage is grizzled and mottled grayish yellow with a broad golden-rufous band extending from the crown of the head to the base of the tail following the midline of the back. Ventral pelage is creamy white and sharply demarcated from the dorsum. Ears are very long and brownish black;vibrissae are long and black. Feet are white and broad, with hindfeet being very elongated with long curved claws. Tail is gray for the basal third and white for the rest with a distinctive white terminal tuft. Skull is elongated and large with an inflated and long rostrum, similar to that of the Black-footed Tree Rat. Females have two pairs of inguinal mammae.

Habitat. Occurs mostly in tropical monsoonal rainforest patches, riparian vegetation, Livistona (Arecaceae) palm forests and eucalypt open forests, often in rugged rocky areas. Occasionally reported also as foraging on beaches and coastal vegetation.

Food and Feeding. The Golden-backed Tree Rat has a varied diet, but mostly consumes flowers and fruits, and includes also invertebrates (particularly termites), grass, and foliage.

Breeding. The Golden-backed Tree Rat probably breeds throughout year. Gestation lasts 47 days, unusually long for Australian rodent species. Litter size 1-3, usually two.

Activity patterns. Golden-backed Tree Rats are nocturnal; they den during the day in tree hollows, but also use hollow logs, crevices in scree and among boulders, and sometimes nest in dense foliage. The species is mostly arboreal, but also forages on the ground.

Movements, Home range and Social organization. Home range reported to vary from 0-2 ha to 30 ha, males having larger home ranges than females. Golden-backed Tree Rats are generally solitary. They use multiple densites.

Status and Conservation. Classified as Least Concern by The IUCN Red List. Also listed as vulnerable under Australian legislation. Severe decline across much of the Goldenbacked Tree Rat's range is probably due to habitat degradation from frequent and extensive fire, and predation by feral cats. Current population trends are not known. Presumed extirpated throughout its former range in the Northern Territory, with last confirmed record in 1969, and extirpated in lower-rainfall areas of the Kimberley over the last ¢.100 years. Subfossil records indicate that this murid’s range extended appreciably farther into lower-rainfall areas probably until time of European settlement of Australia.

Bibliography. Abbott & Burbidge (1995), Baynes & McDowell (2011), Bradley et al. (1987), Gibson & McKenzie (2012), Hohnen et al. (2015), Iredale & Troughton (1934), Jackson & Groves (2015), Kitchener et al. (1981), Mc-Kenzie (1981), Ramsay (1887b), Start et al. (2012), Van Dyck& Strahan (2008), Watts & Aslin (1981), Woinarski, Burbidge & Harrison (2014), Woinarski, Pavey et al. (2007), Ziembicki et al. (2013).