88.

Northern Long-eared Bat

Nyctophilus arnhemensis

French: Nyctophile dArnhem / German: Arnhem-Langohrfledermaus / Spanish: Nictofila de Arnhem

Taxonomy. Nyctophilus arnhemensis D. H. Johnson, 1959,

“Rocky Bay, south of Yirkala, Cape Arnhem Peninsula, Northern Territory, Australia (lat. 12° 16’ S, long. 136° 47' E).”

Nyctophilus arnhemensis is in the bifax species group. It is extremely similar to N. bfax in most morphological characters (although it is smaller) and could potentially be a subspecies of N. bifax, although some morphological data support recognition of the two species as separate. More studies with genetic data are needed to resolve its taxonomy. Monotypic.

Distribution. N coast of Western Australia and Kimberley region (including Bonaparte Archipelago), N Northern Territory (including Tiwi Is, Groote Eylandt, and Sir Edward Pellew Group), and NW Queensland; a specimen was recently recorded from NE Queensland in Cape York, but it needs to be verified.

Descriptive notes. Head-body 40-59 mm, tail 35-641 mm, ear 16-21-5 mm, forearm 33-2-39-9 mm; weight 5-2-9-6 g. The Northern Long-eared Bat has very large ears and unique simple noseleaf consisting of two ridges, one further on muzzle and another immediately above nostrils, with vertical groove in middle and furred trough between them. Dorsal pelage is generally light russet-brown butis occasionally rich dark brown (hairs have dark bases), which shades on side toslightly lighter venter thatis not distinctly different. Face, ears, and wing membranes are medium brown. Rostrum is short and blunt, with ridge across muzzle over nostrils that is moderately developed, consisting of two rounded mounds separated medially by thin vertical groove. Ears are very large and broad, with bluntly rounded tips, horizontal ribbing on inner surfaces, inward curved anterior edges, and smooth posterior edges (ears can fold back at top of thick part of anterior edge); large and furred interauricular band crosses forehead between ears; tragus is small and bluntly rounded attip, being convex on anterior margin. Glans penis is a square-ended cylinder, with flat circular urethral opening on underside near tip. Baculum has moderately thin shaft in dorsal view; tip is deeply bifurcated, and base is strongly bifurcated; in lateral view, baculum is curved downward at base but shaft is straight to pointed tip. Skull is robust; tympanic bullae are small; skull is similar to that of the Eastern Long-eared Bat ( N. bifax) in general morphology; and M? and lower molars are only moderately reduced.

Habitat. Typically wet habitats such as mangrove forests, monsoon forests, rainforest patches, open savanna woodlands, tall open forests, and Melaleuca (Myrtaceae) and Pandanus (Pandanaceae) lined streams, waterholes, and swamps. Northern Longeared Bats are generally found in areas that receive more than 500 mm of rain/year.

Food and Feeding. Northern Long-eared Bats primarily forage by gleaning off the ground and foliage and might also catch prey aerially. They are relatively slow fliers (5 km /h most of the time) but can reach top speeds of 16 km /h. Foraging usually occurs close to and among dense vegetation, and they are highly maneuverable in cluttered areas. Diet in the Top End region consisted largely of termites, water beetles, cockroaches, crickets, and true bugs and occasionally moths and spiders. They reportedly feed on geckos and gecko eggs, but this requires additional verification.

Breeding. Male Northern Long-eared Bats with scrotal testes have been reported in May-November and pregnant females in September—November. Females apparently give birth to twins from late October to February.

Activity patterns. Northern Long-eared Bats roost during the day under bark of large paperbark trees ( Melaleuca), within foliage, and among Pandanus leaves. They have also been reported roosting in houses. They spend the night foraging. Call shape 1s very steep FM sweep, with peak frequencies of 50-52 kHz (mean 50-8 kHz).

Movements, Home range and Social organization. The Northern Long-eared Bat probably roosts in small groups.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Northern Long-eared Bat is widespread and does not seem to face any major threats.

Bibliography. Bullen & McKenzie (2002a), Churchill (2008), Churchill et al. (1984), Flannery (1995b), McKenzie & Churchill (2008), McKenzie, Fontanini et al. (1995), McKenzie, Reardon & Parnaby (2008), Milne (2002), Milne et al. (2016), Parnaby (2009).