167.

Inland Broad-nosed Bat

Scotorepens balstoni

French: Sérotine de Balston / German: Balston-Breitnasenfledermaus / Spanish: Scotorepo de Balston

Other common names: \ Western Broad-nosed Bat

Taxonomy. Scoteinus balstoni Thomas, 1906,

“Laverton, West Australia.”

Two subspecies of S. balston: are normally recognized ( balstoni and influatus), but no subspecies are recognized here, although S. balstoni might represent a species complex. Monotypic.

Distribution. Most of Australia except N Australia, Cape York Peninsula, and E & S coasts.

Descriptive notes. Head-body 42.2-59-7 mm, tail 29-41-7 mm, ear 10-7-14-1 mm, forearm 32—40-5 mm; weight 6-3-14 g. Forearm size increases from west to east and from south to north. There is a larger form in northern inland Queensland (previously known as subspecies influatus). Dorsal pelage ranges from dark brown to pale sandy (most commonly light grayish brown; hairs markedly bicolored with pale bases); ventral pelage is lighter (most commonly pale brown). Ears are relatively slender and subtriangular, anterior edge being smoothly convex with rounded tip; tragus is evenly curved upward, with concave anterior edge, moderately convex posterior edge, and rounded tip. Muzzle is broad, with square shape and inflated glands on either side; nostrils are simple and rounded, diverging from one another. Bare parts offace, ears, and membranes are dark brown. Wings attach at base offifth toe, and uropatagium extends from long calcar to tail tip; calcar stretches about halfway to tail and has small calcaneal lobe. Glans penis has up to 22 spines on head, mainly in two long rows. Baculum is short (2-4-3 mm), with relatively robust shaft that is straight in lateral view; distal head is bifurcated, with two short narrow prongs behind which shaft enlarges into moderately wide lateral flanges; base is broad, and posterior edge is square in line with shaft. Skull is moderately elongated, with relatively narrow rostrum; cranium is flattened in that lateral profile rises only slightly against that of rostrum;sagittal and lambdoidal crests are moderately developed, forming moderate occipital helmet; anterior palatal notch is semicircular, usually ending at mid-point of P* (occasionally to posterior edge of C'); I* is unicuspid and does not touch C'; P* is one-halfto two-thirds the height of C' and touchesit; lower incisors are tricuspid; and P,is small and less than one-half the height of P,. Chromosomal complement has 2n = 30 and FN = 48 in New South Wales.

Habitat. Arid and semiarid habitats throughout inland Australia, often in association with water, along river red gum lined waterways, open woodlands, shrublands, mallee, and grasslands at elevations of 40-480 m in Victoria.

Food and Feeding. Insectivorous. Stomachs from northern parts of the distribution contained cockroaches, termites, crickets, cicadas, bugs, beetles,flies, moths, and ants. In Victoria, diets contained mostly beetles (45% by volume), ants, bugs, moths,flies, and grasshoppers. Foraging is achieved using echolocation in continuousflight c. 15 m aboveground, with rapid diversions to pursue prey. Foraging mainly occurs between trees, not above tree canopies, and at edges of forests, venturing into open areas.

Breeding. In the southern distribution, Inland Broad-nosed Bats mate in April-May, with one young or twins born in mid-November. In northern distributional areas, mating occurs in September, often with twins born, sometimestriplets. Young are well developed and withoutfur at birth. They use recurved milk teeth to secure themselves to their mothers. Young remain attached to the mother until they are c.10 days old and are vocal when not suckling. By this stage, they weigh c. 4 g and are left behind in the roost when their mothers forage at night. Eyes open and fur grows by the time they are 15 days old. After 30 days, they exercise their wings and then go on to forage independently.

Activity patterns. Inland Broad-nosed Bats roost in tree hollows and roofs of buildings and under metal caps of power poles during the day and forage over woodlands and water at night. They start foraging earlier than most other species of bats, usually beginning just at dusk. Flight speeds are 12-21 km/h. Flight efficiency results from a streamlined head, silky fur texture, and small maneuver-enhancing shaped ears. They can enter torpor during the day to conserve energy. In New South Wales, they entered torpor during 70-6% of days for c.7 hours/day, and 29-4% of individuals rewarmed daily using entirely passive rewarming. Call shape is steep FM/QCF sweep, with characteristic frequencies recorded at 34-1-38-7 kHz in Western Australia and 28-34 kHz in New South Wales.

Movements, Home range and Social organization. Inland Broad-nosed Bats roost in colonies of up to 45 individuals. They have been recorded sharing tree hollows and house roosts with free-tailed bats (Ozimops sp.).

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Baverstock et al. (1987), Bondarenco et al. (2016), Bullen & McKenzie (2009), Burbidge et al. (2014), Churchill (2008), Kitchener & Caputi (1985), Lumsden & Bennet (1995), Menkhorst (1996), Parnaby (2008b), Pennay & Lumsden (2008c), Reardon & Flavel (1991), Richards & Hall (2012), Volleth &Tidemann (1991).