Saccolaimus saccolaimus Temminck 1838

16. Bare-rumped Sheath-tailed Bat

Saccolaimus saccolaimus

French: Taphien deTemminck /German: Nacktbauch-Glattnasenfreischwanz / Spanish: Tafozo deTemminck

Other common names: Naked-rumped ree-tail Bat, Naked-rumped Pouched Bat, Naked-rumped Sheath-tailed Bat,

Naked-tailed Saccolaimus, Pouch-bearing Tomb Bat, PouchedTomb Bat

Taxonomy. Taphozous saccolaimus Temminck, 1838,

Java, Indonesia.

There are differing opinions regarding taxonomic status of S. saccolaimus in Australia, and clarification is required.. W. De Vis in 1905 first described Australian forms as a full species Taphozous nudicluniatus. Subsequently, it was placed in the genus Saccolaimus based on cranial, dental, and external morphology. R. E. Goodwin in 1979 and.

T. Chimimba and D. J. Kitchener in 1991 synonymized it with Taphozous (= Saccolaimus) saccolaimus. Some authors have considered nudicluniatus to be subspecies of widespread S. saccolaimus , but validity of subspecific status of nudicluniatus has been questioned. Melanesian and Australian populations are referred to subspecies nudicluniatus, and it is not clear if the Northern Territory population is part of the nominate form, although mtDNA studies showed limited differences between Northern Territory and Queensland groups. Five subspecies recognized.

Subspecies and Distribution.

S. s. sacco / awnus Temminck, 1838 — Sumatra andJava.

S. s. affinis Dobson, 1875 — Borneo and offshore islands including Labuan I.

S. s. crassus Blyth, 1844 — S & SE Asia from India (including Great Nicobar I) and Sri Lanka to Indochina and Peninsular Malaysia.

S. s. nudicluniatus De Vis, 1905 - New Guinea (including Yapen and Trobriand Is), Bismarck Archipelago (New Britain I), Solomon Is (Bougainville and Guadalcanal), and N & NE Australia (Top End and NE Queensland); possibly also on Timor I.

S. s. pluto G. S. Miller, 1910 — Philippines (Luzon, Catanduanes, Mindoro, Negros, and Mindanao Is).

Present also in Sulawesi, Moluccas (Halmahera I), Talaud Is, and Ternate I, but subspecies to which these populations belong are unknown. Distribution and boundaries of different subspecies are poorly known.

Descriptive notes. Head—body 88—100 mm, tail 22—35 mm, ear 16-21 mm, hindfoot 15-17 mm, forearm 68-78 mm; weight 40-50 g. Dorsal fur of the Bare-rumped Sheathtailed Bat is reddish brown to dark brown and irregularly flecked with white patches. Venter is white or less frequently dark brown. Rump, legs, and feet are naked. Males have well-developed glandular gular pouch, which is rudimentary in females. Radialmetacarpal wing pouches are poorly developed. Short, broadly rounded ear is heavily ribbed on interior of pinna. Tragus is short, and its margin is semicircular. Wings are long and narrow. There might be white translucent parts on black-pigmented wings. Other exposed body skin including naked legs and feet is reddish, brown, or black. Strong sagittal crest on skull diverges in postorbital region. Upper incisors are minute.

Habitat. Dry woodlands to rainforests from sea level to elevations of c.1200 m. In Australia, the Bare-rumped Sheath-tailed Bat is restricted to forested habitats and frequently occurs in hollow limbs of Eucalyptus alba ( Myrtaceae ) .

Food and Feeding. The Bare-rumped Sheath-tailed Bat preys on insects high over gardens, woodlands, and rainforests. Audible low-frequency echolocation clicks are produced while foraging.

Breeding. In Australia, parturition of Bare-rumped Sheath-tailed Bats occurs at beginning of wet season, and lactation occurs later in wet season (November—April in Northern Territory). Females give birth to one young. Three to four individuals are often found in tree hollows in Australia. Individual spacing is maintained in roosts.

Activity patterns. The Bare-rumped Sheath-tailed Bat roosts in tree hollows, rock crevices, caves, and tombs; between large boulders; and under eaves of houses. Flight path is high and fest during foraging. Bare-rumped Sheath-tailed Bats are alert in roosts, clinging to substrates while supported by thumbs, wrists, and feet. They scurry over roost substrate if disturbed. Echolocation calls are multiharmonic. There is sharp curvilinear downward sweep in frequency at end of long duration calls. Individuals from northern Australia have characteristic frequencies of 19-4-23-4 kHz (mean 20-8 kHz); whereas, in Brunei, frequency bands are 24-5-26-1 kHz. Calls have long durations of 18-25 milliseconds.

Movements, Home range and Social organization. Colonies of Bare-rumped Sheathtailed Bats range from 3-4 individuals to hundreds of individuals. Contextual use of secretions from throat pouches of males is unknown, but they likely are used in social attraction of breeding females.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Bare-rumped Sheath-tailed Bat has a large distribution and presumably large and stable overall population, uses multiple habitats, occurs in protected areas, faces no significant threats, and does not show evidence of declines affecting significant parts of the population. In Australia, it is listed as critically endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act of 1999. It is listed as endangered under the Queensland Nature Conservation Act of 1992. In the Northern Territory, it is listed as data deficient under the Territory Parks and Wildlife Conservation Act of 2000. Surveys to find roosts and echolocation surveys to better understand distribution and foraging behavior would significantly help to increase knowledge of ecology, behavior, and regional population trends.

Bibliography. Bates, Harrison & Muni (1994a, 1994b, 1994c), Bonaccorso (1998), Brosset (1963), Chimimba & Kitchener (1991), Corbet & Hill (1992), De Vis (1905), lannery (1995a, (1995b), Goodwin (1979), Hall, Thomson & Milne (2008), Heaney, Balete et al. (1998), Heaney, Gonzales et al. (1991), Koopman (1984b), Lekagul & McNeely (1977), Milne (2002), Milne, Jackling et al. (2009), Milne, Reardon &Watt (2003), Molur et al. (2002), Sarker & Sarker (2005), Schulz & Thomson (2007), Simmons (2005), Srinivasulu & Srinivasulu (2005).