Acrobates pygmaeus (Shaw, 1793)

Russell A. Mittermeier & Don E. Wilson, 2015, Acrobatidae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 574-591 : 590

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Narrow-toed Feather-tailed Glider

Acrobates pygmaeus

French: Acrobate pygmée / German: SchmalfulR-Federschwanz-Gleitbeutler / Spanish: Falangero de cola plumosa de dedos estrechos

Other common names: Dusky Feathertail Glider, Feathertail Glider, Feathertailed Glider, Flying Mouse, Pygmy Glider, Pygmy Gliding Possum, Pigmy Phalanger

Taxonomy. Didelphis pygmea Shaw, 1794,

“New Holland.” Restricted by T. Iredale and E. Le G. Troughton in 1934 to “ Sydney, New South Wales.”

Until recently, Acrobates was regarded as monotypic and without clearly defined subspecies or geographical variants. Nevertheless, a recent morphological and molecular study revealed the presence of two well-differentiated species of Acrobates with extensive geographical overlap. Monotypic.

Distribution. SE Australia, from the McPherson and Border ranges in SE Queensland, S to Victoria and SE South Australia; it is absent from the coastal drainages of the Great Dividing Range, S at least to the Wallamba River, and W of the Great Dividing Range in New South Wales (but it probably occurs to the limit of tree growth on the Southern Tableland), and from the inland draining catchments of the Murray Basin in Victoria.

Descriptive notes. Head-body 5-7 cm (maximum 7-7 cm), tail 6.7-5 cm (maximum 8-1 cm); weight 8-12 g (maximum 18-5 g for males, 18 g for non-lactating females, and 21 g for females carrying pouch young). Tail length-to-head-body length ratio is usually 0-9-1-2. Male-biased sexual size dimorphism means that males are, on average, c.10% larger than females. Head-body length of males shows a step-wise decrease from south to north, in general accordance with Bergman’s Rule. Females show no latitudinal variation in body length; hence, degree of male-biased sexual dimorphism is greatest in the south and minimal in the north. Variation in relative tail length is primarily related to individual age (younger individuals have proportionally shorter tails), and there are no clear patterns of geographical variation. Dorsal fur is essentially brown over dark gray but in various shades, ranging from a chestnut brown to a plum brown. Fur on patagium, outer surfaces of limbs, and crown of head is the same color as on the back. Undersurface is white to cream, usually over slate gray but sometimes same color as base in whole or on chest only. Ears and digits are sparsely furred. Tail is furred ventrally to within 1-2 mm of tip, lacking a prehensile section. Tail hair fringe usually has a conspicuous 1-2 mm cream emargination. The Narrow-toed Feather-tailed Glider and the Broad-toed Feather-tailed Glider (A. frontalis) are remarkably similar in body size, general proportions, fur texture, coloration, and patterning. The most important diagnostic features of the Narrow-toed Feather-tailed Glider are: apical toe pads on all manal (hand) digits and pedal (foot) digits four and five rounded, about subequal in length and width, and with weak distal grooves; two distinct raised pads at the base of hallux, both striate; tail furred ventrally to near the tip, ending in a small nubbin of naked skin; tail more often with conspicuous 1-2 mm wide pale margin around tail fringe; and ventral fur on abdomen and chest usually gray-based with cream tipping (some individuals have entirely cream or white fur on throat and upper chest).

Habitat. Forested and wooded landscapes of south-eastern Australia, including open and closed forests, woodlands, and heaths, from near seal level to at least 1200 m in elevation. The Narrow-toed Feather-tailed Glider is regionally sympatric with the Broadtoed Feather-tailed Glider over most of its distribution, and museum locational data are suggestive of actual syntopy in numerous areas.

Food and Feeding. Most field studies of feather-tailed gliders have been carried out in parts of south-eastern Australia where the two species occur in actual or potential sympatry. Previous failure to distinguish the two species means that it is not possible to attribute information on food and feeding gathered during these studies either to the Narrow-toed Feather-tailed Glider or the Broad-toed Feather-tailed Glider.

Breeding. There is no information available for this species.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Recently collected museum voucher specimens of the Narrow-toed Feather-tailed Glider document its continued survival across large parts of its distribution and its occurrence in numerous protected areas.

Bibliography. Iredale & Troughton (1934), Troughton (1967).

Figures

Plate 33 Species Accounts

Distribution. SE Australia, from the McPherson and Border ranges in SE Queensland, S to Victoria and SE South Australia; it is absent from the coastal drainages of the Great Dividing Range, S at least to the Wallamba River, and W of the Great Dividing Range in New South Wales (but it probably occurs to the limit of tree growth on the Southern Tableland), and from the inland draining catchments of the Murray Basin in Victoria.