Rhinolophus borneensis, Peters, 1861

Burgin, Connor, 2019, Rhinolophidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 280-332 : 309-310

60 . Bornean Horseshoe Bat

Rhinolophus borneensis

French: Rhinolophe de Bornéo / German: Borneo-Hufeisennase / Spanish: Herradura de Borneo

Taxonomy. Rhinolophus borneensis Peters, 1861 ,

“ Labuan [Island], Borneo ,” Malaysia .

Traditionally included in the megaphyllus species group, but this needs to be investigated further using genetic techniques, as A borneensis seems to be sister to a clade containing members of the pusillus species group. All mainland South-east Asian populations are here considered to belong to A chaseni , while Indonesian populations are tentatively included in A borneensis .

The identity of Peninsular Malaysian populations is uncertain as no genetic data have been used for testing, so they are here listed under this species, pending further studies. This species may represent a species complex. Three subspecies are recognized.

Subspecies and Distribution.

. b. borneensis Meters, 1861 — Borneo, as well as nearby Banggi, Labuan, and Karimata Is.

R. b. importunus Chasen, 1939 — C & SWJava, including Nusakambanagan I off S Java.

. b. spadix G. S. Miller, 1901 — South Natuna Is.

Taxonomic identity of specimens collected in NW Peninsular Malaysia is uncertain. Also, either this species or the Sulawesi Horseshoe Bat (. celebensis ) was recently captured in Lampung Province, Sumatra, but in that study the two species were not differentiated.

Descriptive notes. Tail 21-26 mm, ear 17-19 mm, forearm 40-44 mm; weight 7-8- 5 g. Dorsal pelage is dark brown (brown morph) to bright reddish brown (orange morph), while ventral pelage is paler. Ears are medium-sized and brown; noseleaf too is brown. Noseleaf has moderately long, nearly cuneate lancet; connecting process is high and rounded, higher than sella; sella is narrow with slight constriction above midpoint and parallel or nearly parallel lateral margins; horseshoe is wide (c.8- 7 mm), nearly covers whole muzzle, has a relatively deep median emargination, and has visible lateral leaflets. Lower lip has three mental grooves. Skull is small but relatively robustly built (zygomatic width generally larger than mastoid width, occasionally subequal); zygomatic arch is highly arched; anterior median swellings are bulbous and longer than they are wide; lateral and posterior swellings are well developed; sagittal crest is weakly to moderately developed; frontal depression is moderately developed; supraorbital ridges are prominent and more or less sharp. P2 is reduced but almost always within tooth row, separating C1 and P4; P3 is moderate to small in size and usually completely displaced labially, nearly always allowing P2 and P4 to touch (rarely slightly separated).

Habitat. Primary and secondary tropical forests at elevations from sea level up to C. 1000 m. Recorded in dipterocarp forest in Sarawak, Borneo.

Food and Feeding. The Bornean Horseshoe Bat feeds on insects and uses perches to feed on once the insect is captured.

Breeding. No information.

Activity patterns. Bornean Horseshoe Bats are nocturnal, foraging at night and roosting during the day. They are known to roost in cave systems in Borneo as well as in hollow bamboos and trees, among young leaves of bananas, and in rock crevices. Call shape is FM/CF/FM and the peak F has been recorded at 81-8 kHz in Sabah, Borneo.

Movements, Home range and Social organization. Bornean Horseshoe Bats are known to roost in large colonies of several hundred individuals.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Bornean Horseshoe Bat has a wide distribution and is considered common at least in Borneo, which comprises most of its range. It is rare in some regions, especially in Java. Populations are probably most threatened by habitat loss and fragmentation due to deforestation and agricultural expansion.

Bibliography. Corbet & Hill (1992), Csorba, Fuisz & Kelen (1997), Csorba, Ujhelyi & Thomas (2003), Francis et al. (2010), Hall (1996), Huang, J. C.C. et al. (2014), Hutson, Kingston & rancis (2008a), Kruskop (2011), Lim et al. (2017), Mohd-Azlan et al. (2008), Rahman et al. (2011).

Figures

On following pages: 52. Eastern Horseshoe Bat (Rhinolophus megaphyllus}; 53. Insular Horseshoe Bat (Rhinolophus keyensis}; 54. Yellow-faced Horseshoe Bat (Rhinolophus virgo}; 55. Madura Horseshoe Bat (Rhinolophus madurensis}; 56. Sulawesi Horseshoe Bat (Rhinolophus celebensis}; 57. Robinson's Horseshoe Bat (Rhinolophus robinsoni); 58. Indochinese Horseshoe Bat (Rhinolophus chasem); 59. Anamban Horseshoe Bat (Rhinolophus nereis}; 60. Bornean Horseshoe Bat (Rhinolophus borneensis); 61. Malayan Horseshoe Bat (Rhinolophus malayanus}; 62. Acuminate Horseshoe Bat (Rhinolophus acuminatus}; 63. Acuminate Horseshoe Bat (Rhinolophus acuminatus}; 64. Little Japanese Horseshoe Bat (Rhinolophus cornutus}; 65. Yaeyama Horseshoe Bat (Rhinolophus perditus}; 66. Mountain Horseshoe Bat (Rhinolophus monticolus}; 67. Shortridge's Horseshoe Bat (Rhinolophus shortridgei}; 68. Formosan Horseshoe Bat (Rhinolophus monoceros}; 69. Least Horseshoe Bat (Rhinolophus pusillus}; 70. Little Nepalese Horseshoe Bat (Rhinolophus subbadius}; 71. Convex Horseshoe Bat (Rhinolophus convexus}; 72. Andaman Horseshoe Bat (Rhinolophus cognatus}; 73. Glossy Horseshoe Bat (Rhinolophus refulgens}; 74. Blyth's Horseshoe Bat (Rhinolophus lepidus};

Subspecies and Distribution. . b. borneensis Meters, 1861 — Borneo, as well as nearby Banggi, Labuan, and Karimata Is. R. b. importunus Chasen, 1939 — C & SWJava, including Nusakambanagan I off S Java. . b. spadix G. S. Miller, 1901 — South Natuna Is. Taxonomic identity of specimens collected in NW Peninsular Malaysia is uncertain. Also, either this species or the Sulawesi Horseshoe Bat (. celebensis ) was recently captured in Lampung Province, Sumatra, but in that study the two species were not differentiated.