Bettongia tropica, Wakefield, 1967

Russell A. Mittermeier & Don E. Wilson, 2015, Potoroidae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 600-628 : 627

5.

Northern Bettong

Bettongia tropica

French: Bettong du Nord / German: Nordliches Blrstenrattenkanguru / Spanish: Betong septentrional

Other common names: Brush-tailed Bettong, Tropical Bettong

Taxonomy. Bettongia tropica Wakefield, 1967 ,

“ Mount Spurgeon , 3700 feet, northeastern Queensland,” Australia.

Whether this taxon represents a full species or is a subspecies of B. penicillata has been a matter of dispute; a comprehensive comparison of B. tropica with eastern B. penicillata has not yet been made and should be a priority for future research. Generally, it is now treated as a distinct species. A genetic study revealed well-differentiated northern and southern mtDNA clades within B. tropica , with admixture in the Lamb Range population. Monotypic.

Distribution. Mt Windsor Tableland, Mt Carbine Tableland, Lamb Range, and Coane Range, in NE Queensland.

Descriptive notes. Head—body 29.5-43.2 cm,tail 26.8-35 cm; weight 0.9-1.4 kg. Gray, grizzled with white, dorsally, paler ventrally. Limbs paler than body. Partial dark eye-ring in some specimens. Tail paler ventrally and darkens distally, with a dark dorsal crest toward tip; a white tail tip is occasionally present. Diploid chromosome numberis 22.

Habitat. Grassy open eucalypt woodland and forest adjacent to rainforest; on granitic soils, from 400 m to 1200 m elevation, mostly above 800 m.

Food and Feeding. Mycophagous, feeding primarily on hypogeal (truffle-like) fungi obtained by digging with the strongly clawed forepaws. Fungi make up 30% to more than 60% of the diet throughout the year. Roots, tubers, underground parts of grasses, seeds, and invertebrates are also eaten. Seasonal and geographical variation in diet reflects differing availability of fungi.

Breeding. Females reach sexual maturity at about ten months and males at c.15 months. Females breed continuously, producing a single young per pregnancy and up to three young per year. They exhibit embryonic diapause and usually mate within 24 hours of having given birth. The estrous cycle is 21-23 days and gestation is 20-23 days. Following birth, the young spends c¢.3-5 months in the pouch and is weaned at 5-5-6 months. The mating system appears mixed, with evidence of both promiscuity and serial monogamy.

Activity patterns. Nocturnal; spends daylight hours alone in a well-camouflaged nest constructed in a shallow depression dug under dense vegetation, close to fallen trees, or in the open. Nests are ovoid, have a single entrance, are composed of grass and other vegetation, and lined with fine plant material. Up to three nests may be used by the same individual, with each rarely used for more than two days in succession. Nests tend to be clustered within a small area (10 ha for males, 5 ha for females) of the home range. Afterfire, these bettongs may use boulderpiles, fallen trees, or hollow logs for shelter. They emerge after sunset to forage widely and relatively evenly through their home range, returning to a nest before dawn.

Movements, Home range and Social organization. Solitary. Home ranges average 59 ha (19-138 ha) and are similar for males and females. Smaller core nesting areas, averaging 5-5 ha for females and 10 ha for males, are maintained within the home ranges. Dispersal appears to be male-biased, young females settling close to their mother, and young males dispersing a short distance away (average 1-3 km).

Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red List. Listed also as endangered in Australia. The Northern Bettong has a naturally restricted and highly fragmented distribution, making it especially vulnerable to stochastic events. Populations at Mt Windsor Tableland, Mt Carbine Tableland, and the Coane Range are only small. Most populations are known to have declined and some now appear to be extinct; this species formerly occurred also near Ravenshoe and farther south, in Dawson Valley near Rockhampton. The threats to the Northern Bettong are uncertain, but include loss of habitat due to invasion ofits preferred eucalypt forest/woodland by rainforest as a result of a reduction in fire frequency. Climate change may also be reducing the availability of truffle-like fungi. The impact ofcattle grazing, introduced predators such as Red Fox (Vulpes vulpes), and competitors such as feral pigs is unclear, but may well be significant. Most remaining habitat has been incorporated into protected areas and a Recovery Plan has been prepared. A trial reintroduction near Ravenshoe was unsuccessful. A captive population established in 1996 has now been disbanded.

Bibliography. Bateman et al. (2011), Burnett & Winter (2008g), Claridge et al. (2007), Dennis (2001, 2012), Hayman (1989), Johnson, C.N. & Mcllwee (1997), Johnson, PM. (2003), Johnson, PM. & Delean (2001), Pope, Estoup & Moritz (2000), Pope, Vernes et al. (2012), Seebeck et al. (1989), Smith (1998), Vernes & Pope (2001a, 2001b), Wakefield (1967), Winter, Johnson & Vernes (2008), Woinarski et al. (2014bn).

Figures

1. Rufous Bettong (Aepyprymnus rufescens), 2. Burrowing Bettong (Bettongia lesueur), 3. Eastern Bettong (Bettongia gaimardi), 4. Brush-tailed Bettong (Bettongia penicillata), 5. Northern Bettong (Bettongia tropica), 6. Long-footed Potoroo (Potorous longipes), 7. Long-nosed Potoroo (Potorous tridactylus), 8. Gilbert's Potoroo (Potorous gilbertii)

Distribution. Mt Windsor Tableland, Mt Carbine Tableland, Lamb Range, and Coane Range, in NE Queensland.