Wyulda squamicaudata, Alexander, 1919

Russell A. Mittermeier & Don E. Wilson, 2015, Phalangeridae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 456-497 : 484-485

5.

Scaly-tailed Possum

Wyulda squamicaudata

French: Phalanger a queue écailleuse / German: Schuppenschwanzkusu / Spanish: Cuscus de cola espinosa

Other common names: Scaly-tailed Phalanger, Wyulda

Taxonomy. Wyulda squamicaudata Alexander, 1919 ,

“ Violet Valley Station , via Wyndham [= East Kimberley region],” Western Australia, Australia.

This species is monotypic.

Distribution. NW Australia, patchily across the Kimberley region in Western Australia, from Kalumburu in the N to North Derby in the S, including Bigge and Boongaree Is. The species was recently confirmed to occur in the East Kimberley (Cockburn Ranges) for the first time since its initial scientific discovery in 1917.

Descriptive notes. Head-body 30-47 cm, tail 28-30 cm; weight 0.9-2 kg. The Scalytailed Possum is a small, stocky possum with the upperparts uniformly gray, flecked with brown, an indistinct dorsalstripe on head and back, rufous brown patch on dorsal surface of rump and distal tail, and cream-colored under parts. It has very small ears compared with species in the related genus Trichosurus . The Scaly-tailed Possum differs from all phalangerids in having a distinctive tail that is dorsally and ventrally naked beyond its proximal base, white-tipped for distal one-third), and covered in coarse, rasp-like scales—origin of its common and scientific names. The Scaly-tailed Possum has small claws, with greatly enlarged fleshy apical pads on the fingers. Itis also unique among phalangerids in that it appears to lack sternal and paracloacal glands. Skull of the Scaly-tailed Possum differs from species of Trichosurus in that large upper premolar is elongated vertically and is longer than first molar, and upper molars are more square rather than rectangular in shape.

Habitat. Open woodlands, closed forest, and vine thickets where boulders and rock piles offer shelter.

Food and Feeding. The Scaly-tailed Possum primarily feeds in trees on leaves, flowers, and nuts of plants of the myrtle family including Xanthostemon eucalyptoides , X. paradoxus, Eucalyptus spp. , and Planchonia careya ( Lecythidaceae ). It will also come to the ground to forage on flowers, seeds, and stems of the perennial herb Trachymene didiscoides ( Apiaceae ). Captive Scaly-tailed Possums have been observed to habitually hide small caches of food such as nuts, and they also eat fruits and insects. When feeding on foliage, they use both paws to pull leaves attached to branches toward the mouth, with segments of leaves being cut by incisors then pushed back to molars to be chewed.

Breeding. Female Scaly-tailed Possums give birth to a single young in the dry season in March-August, which leave the pouch after 150-210 days but can continue to suckle until ¢.250 days of age. Some young achieve one-half of adult size by December or January, but they are not sexually mature until c.2 years of age.

Activity patterns. The Scaly-tailed Possum is nocturnal, resting during the day alone in one of several dens (up to 500 m apart) within rocky piles, sunken rock piles, under large rock slabs, or in underground rock crevices. In some locations, they are sympatric with the Rock Ring-tailed Possum ( Petropseudes dahlit ) and may compete for den sites. At night Scaly-tailed Possums are solitary and forage alone. They are agile climbers that can leap 1 m between branches and use their prehensile tails to grasp tree branches, allowing them to hang vertically in the air while feeding on foliage located below.

Movements, Home range and Social organization. Mean home range of the Scalytailed Possum is c.1 ha (range 0-03-2 ha), with densities of 2-3—4-6 ind/ha. Their call is a chittering, chirping noise. When agitated, they show aggression by continuously moving their tails side to side through the air in a “tail-wag” motion.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. Very little is known about conservation status of the Scaly-tailed Possum. Major threats may be historically changed fire regimes and predation by introduced domestic and feral cats. Proposed mining activity could affect the Scaly-tailed Possum on the Mitchell Plateau.

Bibliography. Alexander (1919), Burbidge & Webb (2008), Doody et al. (2012), Fry (1971), Humphreys et al. (1984), McKnight (2008g), Runcie (1999), Woinarski et al. (2014bv).

Figures

1. Common Brush-tailed Possum (Trichosurus vulpecula), 2. Coppery Brush-tailed Possum (Trichosurus johnstonii), 3. Short-eared Brush-tailed Possum (Trichosurus caninus), 4. Mountain Brush-tailed Possum (Trichosurus cunningham), 5. Scaly-tailed Possum (Wyulda squamicaudata), 6. Common Bear Cuscus (Aulurops ursinus), 7. Talaud Bear Cuscus (Aulurops melanotis), 8. Mountain Bear Cuscus (Aulurops furvus), 9. Small Sulawesi Cuscus (Strigocuscus celebensis), 10. Small Sangihe Cuscus (Strigocuscus sangirensis)

Distribution. NW Australia, patchily across the Kimberley region in Western Australia, from Kalumburu in the N to North Derby in the S, including Bigge and Boongaree Is. The species was recently confirmed to occur in the East Kimberley (Cockburn Ranges) for the first time since its initial scientific discovery in 1917.