Rhinolophus pusillus, Temminck, 1834

Burgin, Connor, 2019, Rhinolophidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 280-332 : 313

69 . Least Horseshoe Bat

Rhinolophus pusillus

French: Rhinolophe pusille / German: Kleinste Hufeisennase / Spanish: Herradura de nariz pequena

Taxonomy. Rhinolophus /wsz'ZZws Temminck, 1834 ,

“ Java,” Indonesia .

Rhinolophus pusillus is placed in the pusillus species group. Race blythi is occasionally treated as a separate species, but is best included in R pusiUus for the present until further studies clarify its relationship with other populations of R pusillus . Rhinolophus pusillus, as currently constituted, is paraphyletic with respect to R lepidus , R monticolus , R shortridgei , and R monoceros , and it may well represent a species complex. Distinctions between subspecies are poorly demarcated, as are the respective distributions, and a detailed study is needed to resolve the several issues surrounding this species. Nine subspecies are tentatively recognized.

Subspecies and Distribution.

R.p. pusillus Temminck, 1834 - N Sumatra, N, E & S Borneo (including Banggi I), W Java, and Bali I.

R. p. blythi K. Andersen, 1918 - N India (Uttarakhand, Sikkim, West Bengal, Assam, Meghalaya, and Arunachal Pradesh), Nepal, Bhutan, and SE Bangladesh.

R.p. calidus G. M. Allen, 1923 -SE China (Guizhou, Guangxi, Guangdong, and Fujian, along with a recent record from Beijing area that may represent this subspecies).

R. p. gracilis K. Andersen, 1905 - S India (Andhra Pradesh, Karnataka, Kerala, and Tamil Nadu).

R.p. lakkhanae Yoshiyuki, 1990 - S China (Yunnan), Thailand, Laos, Vietnam (including Cat Ba I), Cambodia, and Peninsular Malaysia (including Tioman I).

R.p. minutillusG. S. Miller, 1906 —Anambas Is (Siantan).

R.p. pagi Tate & Archbold, 1939 — Mentawai Is (North Pagai).

R.p. parcus G. M. Allen, 1928 - Hainan I, China.

R. p. szechwanus K Andersen, 1918 - Myanmar and C China (Sichuan, Guizhou, Hubei, and probably Yunnan).

Descriptive notes. Head-body 30-42 mm, tail 13-26 mm, ear 13—20 mm, hindfoot 6-8 mm, forearm 33-41- 6 mm; weight 3- 3-8 g. Dorsal pelage is dark brown to smoky gray or cinnamon brown, and ventral pelage grayish white or reddish, matching dorsum but paler. Ears are medium-sized. Noseleaf has variable lancet that ranges from elongate with concave sides to short and nearly triangular with parallel sides; connecting process is generally triangular (or hom-shaped, curving forward in some individuals); sella is slightly constricted medially, gradually narrowing to widely rounded tip; horseshoe is relatively wide (6-8 mm) with small median emargination, and lacks lateral leaflets. There are three mental grooves on lower lip. Baculum is very large for horseshoe bat, has distinct but weak dorsal bend at tip and base, roughly cylindrical shaft, thin, rounded, and laterally widened tip, and wide basal cone with deep emargination. Skull is moderately robust (zygomatic breadth is usually subequal to mastoid breadth but can be either slightly larger or smaller); anterior median swellings are very small; posterior swellings are more or less well inflated; rostral profile is nearly straight or slightly sloping posteriorly; sagittal crest is weakly to moderately developed; frontal depression is shallow or nearly straight; supraorbital crests are inconspicuous and low. C1 is moderately long; P2 is well developed and in the tooth row, separating C1 from P4; P3 is minute to mediumsized and usually extruded from the tooth row; P2 and P4 are variably separated or in contact. Chromosomal complement has 2n = 62 and FN = 63 (Hainan) or 64 ( Thailand).

Habitat. A variety of forest habitats at elevations of 200-1370 m, ranging from mature primary forests to disturbed forests.

Food and Feeding. The Least Horseshoe Bat probably forages for insects by perchhunting; it has been observed foraging among clumps of bamboo and small limestone boulders. Five fecal samples in Beijing consisted of Diptera (45% by volume), Lepidoptera (42%), and Coleoptera (13%).

Breeding. Very little is known about its breeding biology, but pregnant females were captured in mid-May, and lactating females in mid-June in Guangxi.

Activity patterns. Least Horseshoe Bats usually roost in caves by day, although roosts have also been recorded in the roofs of bungalows. They emerge from their day roosts to forage through the night, and have been observed leaving their roosts in early evening (18:00 h) in Myanmar, dispersing by 18:30 h. Search call shape is FM/CF/FM, with a peak F of 105-2-109-7 kHz in Beijing and 111-2 kHz in Guangxi, 108-9-114-1 kHz in Cambodia (start frequencies of 95—111 kHz and end frequencies of 95-105 kHz), and 92-5 kHz in Peninsular Malaysia; and a call duration of 20—50 milliseconds (mean of 40 milliseconds) in China and 14-7-34-1 milliseconds in Cambodia (interpulse interval of 18-2-38-6 milliseconds).

Movements, Home range and Social organization. Day roosts vary from a few individuals to thousands. In north-western Thailand, Least Horseshoe Bats were observed roosting in clusters of 55-1500 individuals in a cave.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Least Horseshoe Bat is widespread and appears to be common throughout much of its distribution. However, the species as currently constituted may well comprise a group of several species with smaller distributions; once the taxonomy is clarified further, the conservation status of the different forms may change.

Bibliography. Bates & Harrison (1997), Bates eta/. (2004), Corbet & Hill (1992), Csorba eta/. (2003), Dejtaradol (2009), Francis (2008a), Harada (1985), Hutson, Kingston &Walston (2008), JiangTinglei, Metzner eta/. (2010), Li Gang eta/. (2006), Ma Xin eta/. (2016), Malia (2000), Patawang et al. (2017), Phauk eta/. (2013), Saha et al. (2017a), Sinha (1973), Smith & XieYan (2008), Soisook eta /. (2016), Struebig eta/. (2005), Wei Song eta/. (2012), WuYi & Harada (2005), WuYi, Motokawa, Harada et al. (2012), WuYi, Motokawa, LiYuchun eta/. (2009), Zhang Lin et al. (2018).

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. R.p. pusillus Temminck, 1834 - N Sumatra, N, E & S Borneo (including Banggi I), W Java, and Bali I. R. p. blythi K. Andersen, 1918 - N India (Uttarakhand, Sikkim, West Bengal, Assam, Meghalaya, and Arunachal Pradesh), Nepal , Bhutan , and SE Bangladesh . R.p. calidus G. M. Allen, 1923 -SE China (Guizhou, Guangxi, Guangdong, and Fujian, along with a recent record from Beijing area that may represent this subspecies). R. p. gracilis K. Andersen, 1905 - S India (Andhra Pradesh, Karnataka, Kerala, and Tamil Nadu). R.p. lakkhanae Yoshiyuki, 1990 - S China (Yunnan), Thailand , Laos , Vietnam (including Cat Ba I), Cambodia , and Peninsular Malaysia (including Tioman I). R.p. minutillusG. S. Miller, 1906 —Anambas Is (Siantan). R.p. pagi Tate & Archbold, 1939 — Mentawai Is (North Pagai). R.p. parcus G. M. Allen, 1928 - Hainan I, China . R. p. szechwanus K Andersen, 1918 - Myanmar and C China (Sichuan, Guizhou, Hubei, and probably Yunnan).