Rhinolophus pumilus, K. Andersen, 1905

Burgin, Connor, 2019, Rhinolophidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 280-332 : 311

64 . Okinawa Horseshoe Bat

Rhinolophus pumilus

French: Rhinolophe d'Okinawa / German: Okinawa-Hufeisennase I Spanish: Herradura de Okinawa

Other common names: Okinawa Little Horseshoe Bat

Taxonomy. Rhinolophus comutus pumilus K. Andersen, 1905 ,

“ Loo-choo Islands ,” Okinawa Prefecture, Japan .

Rhinolophus pumilus is included in the pusillus species group and appears to be sister species to. comutus. Echolocation frequency of. pumilus is higher than in. cornutus , but this increase follows the generally increasing cline in the echolocation frequency within R comutus from north to south. Nevertheless, based on unpublished genetic data collected by K. Armstrong, A pumilus is tentatively treated as a species here, but an in-depth study is urgently needed; the probably extinct taxon miyakonis from Miyako Island, occasionally treated as subspecies of A pumilus , is here treated as a synonym. Monotypic.

Distribution. S Japan, Okinawa Is, Iheyajima (one record in 1992), Tokashikijima (one record in 1978), Kumejima, Miyakojima (probably extinct after 1971), and Irabu Is.

Descriptive notes. Head—body 36-43- 3 mm, ear 19- 1 mm (average), hindfoot 8- 6 mm (average), forearm 38-40- 5 mm. The Okinawa Horseshoe Bat is similar to the Little Japanese Horseshoe Bat (. cornutus ). Pelage is woolly and glossy and the dorsal pelage is medium brown (bases of hair being lighter) whereas the ventral pelage is similar but paler (darker than the Littlejapanese Horseshoe Bat). Ears are moderate-sized. Noseleaf has a concave-sided lancet; connecting process is subtriangular and curved with a slightly concave or straight anterior margin; sella is pandurate, being constricted above the middle, and has a broadly rounded tip; horseshoe is not very broad but broader than in the Littlejapanese Horseshoe Bat (7- 2 mm), with no lateral leaflets, and short, narrow median emargination. Lower lip has three mental grooves. Baculum averages 4- 2 mm long and has a very deep dorsal notch on basal cone with small ventral notch; shaft is nearly cylindrical and is bent on distal one-half. Skull is long (longer than in the Littlejapanese Horseshoe Bat) and narrow, and zygomatic width is subequal to mastoid width; anterior median swellings are small and subcircular; posterior compartments are moderate in size; rostral profile slopes gently posteriorly or is rarely almost straight; sagittal crest is weakly to moderately developed; frontal depression varies from moderate to fairly deep; supraorbital crests are conspicuous but not generally sharp. P2 is minute and completely external to tooth row (occasionally absent); P3 is medium-sized to small and is external to tooth row. Dental formula is the usual of 32 teeth for the genus or only 30 teeth when an upper premolar is missing. Chromosomal complement has 2n = 62 and FNa = 60.

Habitat. Woodland habitats.

Food and Feeding. The Okinawa Horseshoe Bat is insectivorous.

Breeding. The species appears to exhibit restricted seasonal monoestry and has been observed breeding in November to January. Females give birth to a single young from May to June.

Activity patterns. The Okinawa Horseshoe Bat forages during the night and roosts by day in natural caves, abandoned mines, and bomb shelters. Search call shape is FM/ CF/ FM. On northern Okinawajima, males had peak frequencies of 105-6—110-9 kHz (mean of 108-2 kHz) whereas females had 107-7—113 kHz (mean of 110-6 kHz). Peak frequencies on southern Okinawajima were even higher, with males at 112-8— 119-3 kHz (mean of 116 kHz) and females at 104-6—120-1 kHz (mean of 117-4 kHz). Females had significantly higher average frequencies than males on Okinawajima.

Movements, Home range and Social organization. The Okinawa Horseshoe Bat roosts to colonies.

Status and Conservation. Not assessed as a separate species on The IUCN Red List, where it is included under the Least Horseshoe Bat ( pusillus } as Least Concern. Listed as endangered in theJapanese Red List. The Okinawa Horseshoe Bat probably became extinct on Miyako c.40 years ago and on Irabu c.15 years ago, although more intensive surveys are needed to confirm this. Population on Kumejima has experienced declines. The species appears to be threatened by habitat destruction and by disturbances related to tourism in the Ryukyu Islands .

Bibliography. Ando et al. (1980c), Chen Shiangfan etal. (2006), Fukui etal. (2009), Hutson, Kingston & Walston (2008), Li Gang etal. (2006), Ohdachi et al. (2015), WuYi, Motokawa et al. (2012),Yoshino etal. (2006), Yoshiyuki (1989), 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};

Distribution. S Japan , Okinawa Is, Iheyajima (one record in 1992), Tokashikijima (one record in 1978), Kumejima, Miyakojima (probably extinct after 1971), and Irabu Is.