Rhinolophus trifoliatus, Temminck, 1834

Burgin, Connor, 2019, Rhinolophidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 280-332 : 328

98 .

Trefoil Horseshoe Bat

Rhinolophus trifoliatus

French: Rhinolophe à trèfle / German: Kleeblatt-Hufeisennase / Spanish: Herradura de trébol

Taxonomy. Rhinolophus trifoliatus Temminck, 1834 ,

Bantam , Westjava , Indonesia .

Rhinolophus trifoliatus is placed in the trifoliatus species group. It appears to be close to R.sedulus . Four subspecies are recognized.

Subspecies and Distribution. R. t. trifoliatus Temminck, 1834 — Sumatra, Belitung I, Borneo, WJava, and Banta I. R. t. edax K. Andersen, 1918 - NE India (two records in West Bengal and Assam), S China (one record in Guizhou), S Myanmar, C & S Thailand, Peninsular Malaysia, and Singapore. R. t. niasensis K. Andersen, 1906 — Nias I. R. t. solitarius K Andersen, 1905 - Bangka I.

Descriptive notes. Head—body 514- 65 mm, tail 25- 5—38 mm, ear 21- 8—28 mm, hindfoot 8—13 mm, forearm 45—57 mm; weight 10-20 g. Fur is long and woolly; dorsal and ventral pelage is pale buffy brown to brownish gray, appearing almost grayish white in some individuals. Ears are moderately long and yellow or yellowish brown, at base or up to tip. Noseleaf is yellow or yellowish brown, with a long lancet that is slightly emarginateti below the tip; connecting process is low and rounded; sella is narrow and has large circular lateral lappets at base; horseshoe is relatively wide (10-5—12- 4 mm) and has a moderate median emargination. Lower lip has one mental groove. Skull is heavy and robust (zygomatic width is much wider than mastoid width); anterior median swellings are relatively well inflated but do not reach anteriorly to border ofnasal orifice; posterior swellings are reduced; frontal depression is deep to very deep and narrow; supraorbital crests are high with sharp ridges; sagittal crest is very high anteriorly but flattens posteriorly. C1 is massive and short; P2 is small to medium-sized, and within tooth row or occasionally slighdy extruded from it; C1 and P4 are separated; P is small to minute, and extruded to variable extent from tooth row, or sometimes absent; P2 and P4 vary from being in contact to well separated, depending on the position or absence of the P3. Dental formula is typical of 32 teeth or 30 when lower premolar is missing. Chromosomal complement has 2n = 32 and FNa = 60 (Peninsular Malaysia).

Habitat. Typically found in primary and secondary tropical moist forest, generally in lowland areas. Known from dense evergreen forests in southern Myanmar, and can be found in most forest types in Borneo, including mangroves, and is common in heath forest. In Singapore, the species was acoustically recorded only from primary forest, although a female was found roosting in secondary forest Recorded from sea level up to 1800 m.

Food and Feeding. Trefoil Horseshoe Bats appear to hunt insects by fly-catching. The low wing loading and aspect ratio of the wings indicate that the species is a slow but maneuverable flier.

Breeding. The Trefoil Horseshoe Bat is thought to breed once a year, although it may breed at any time of the year. In Krau, Peninsular Malaysia, the species apparently breeds year-round, but most births occur early in the year.

Activity patterns. The Trefoil Horseshoe Bat roosts under leaves, commonly palm leaves, in the forest understory. Call shape is FM/CF/FM, with a peak F frequency of 53-1 kHz and duration of 44-5 milliseconds recorded in Singapore, 50—53-5 kHz from peninsular Thailand, and 53 kHz from Peninsular Malaysia.

Movements, Home range and Social organization. Trefoil Horseshoe Bats roost singly, and are thought to be solitary.

Status and Conservation. Classified as Least Concern on The IUCNed List. The Trefoil Horseshoe Bat appears to be common where favorable habitat exists. The species is threatened by deforestation resulting from logging and agricultural expansion. Tourism-related activities are also thought to be a significant threat to the species.

Bibliography. Bates & Harrison (1997), Csorba eta/. (2003), rancis (2008 a), Hutson, Kingston, rancis, Molur & Srinivasulu (2008), Kingston (2013), Kingston, rancis et al. (2003), Kingston, Jones et al. (2000), Kingston, Lim & Zubaid (2006), Lane et al. (2006), Molur et al. (2002), Phillipps & Phillipps (2016), Pottie et al. (2005), Sinha (1973), Smith & XieYan (2008), Soisook, Niyomwan et al. (2010), Soisook, Struebig et al. (2015), Srinivasulu & Srinivasulu (2012), Tingga et al. (2012), Volleth et al. (2015), Zhang Lin et al. (2018).

Figures

On following pages: 94. Thomas's Horseshoe Bat (Rhinolophus thomasi); 95. Lesser Horseshoe Bat (Rhinolophus hipposideros); 96. rancis's Woolly Horseshoe Bat (Rhinolophus trancisi); 97. Lesser Woolly Horseshoe Bat (Rhinolophus sedulus); 98. Trefoil Horseshoe Bat (Rhinolophus trifoliatus); 99. Northern Woolly Horseshoe Bat (Rhinolophus perniger); 100. Selangor Woolly Horseshoe Bat (Rhinolophus luctoides); 101. Malaysian Woolly Horseshoe Bat (Rhinolophus mono); 102. Great Woolly Horseshoe Bat (Rhinolophus luctus); 1.03. Beddome's Woolly Horseshoe Bat (Rhinolophus beddomei); 104. Formosan Woolly Horseshoe Bat (Rhinolophus formosaë); 105. Thailand Horseshoe Bat (Rhinolophus thailandensis); 106. Dobson's Horseshoe Bat (Rhinolophus yunanensis); 107. Chiew Kwee's Horseshoe Bat (Rhinolophus chiewkweeae); 108. Pearson's Horseshoe Bat (Rhinolophus pearsonii); 109. Mitred Horseshoe Bat (Rhinolophus mitratus).

Subspecies and Distribution. R. t. trifoliatus Temminck, 1834 — Sumatra, Belitung I, Borneo, WJava, and Banta I. R. t. edax K. Andersen, 1918 - NE India (two records in West Bengal and Assam), S China (one record in Guizhou), S Myanmar, C & S Thailand , Peninsular Malaysia , and Singapore . R. t. niasensis K. Andersen, 1906 — Nias I. R. t. solitarius K Andersen, 1905 - Bangka I.