Rhinolophus perditus, K. Andersen, 1918

Burgin, Connor, 2019, Rhinolophidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 280-332 : 311-312

65 . Yaeyama Horseshoe Bat

Rhinolophus perditus

French: Rhinolophe des Yaeyama / German: Yaeyama-Hufeisennase I Spanish: Herradura de Yaeyama

Other common names: Lost Horseshoe Bat, Ryukyu Horseshoe Bat, Yaeyama Little Horseshoe Bat; Imaizumi's Horseshoe Bat (imaizumii)

Taxonomy. Rhinolophus perditus K. Andersen, 1918 ,

“ Ishigaki, southern Liu-Kiu [= Ryukyu Islands] /’ Japan .

Rhinolophus perditus is included in the pusillus group. It is occasionally treated as a subspecies or synonym of R. comutus , but it is morphologically distinguishable from R. comutus occurring allopatrically on other Ryukyu Islands, and can also be differentiated based on echolocation. There are differing opinions regarding the taxonomic position of R. imaizumii in relation to R.perditus . The two taxa are morphologically distinguishable based on craniodental morphometries, but no genetic data have yet been shown to differentiate them; they have variously been treated as distinct species or as a single species, R.perditus (including imaizumii as ajunior synonym). It is possible that both may occur on some of the islands, lending to potential further confusion, but this has not yet been proven. Until a focused study using both genetic and morphological data is undertaken, the two taxa are considered subspecies under R.perditus . Two subspecies are tentatively recognized.

Subspecies and Distribution.

R.p. perditus K. Andersen, 1918 - Yaeyama Is (Ishigakijima and Taketomi), Ryukyu Is.

R.p. imaizumii Hill & Yoshiyuki, 1980 — Yaeyama Is (Iriomotejima and Kohamajima), Ryukyu Is.

Descriptive notes. Head-body 39-47- 8 mm, tail 18-1-26- 1 mm, ear 17-9-18- 9 mm, hindfoot 8- 4—9 mm, forearm 40- 3—43 mm. The Yaeyama Horseshoe Bat is similar to the Littlejapanese Horseshoe Bat (. cornutus ). Subspecies imaizumii is larger than perditus and the two taxa do not overlap in craniodental morphometries. Pelage is woolly and glossy, dorsal pelage being bright brown (base of hairs light beige), ventral pelage similar but paler and creamier brown. Ears are moderate-sized. Noseleaf has a slightly concave-sided lancet; connecting process is hom-like, curved anteriorly, narrow, and slender; sella has a broad base with a slightly constricted center and a rounded, anteriorly deflected tip; horseshoe is not very broad (7- 3 mm), with no lateral leaflets, and a short, narrow median emargination. Lower lip has three mental grooves. Baculum is 4-2-4- 4 mm long and has a very deep dorsal notch on the basal cone with a small ventral notch; shaft is nearly cylindrical and is bent on the distal one-half. Skull is similar to that of the LittleJapanese Horseshoe Bat but can be distinguished based on craniodental measurements; skull is long and narrow, and zygomatic width is slighdy greater than ( imaizumii ) or subequal to ( perditus ) mastoid width; anterior median swellings are small and subcircular; posterior compartments are moderate in size; rostral profile slopes posteriorly; sagittal crest is weakly to moderately developed; supraorbital crests are weak; frontal depression is shallow. Dental distinctions between subspecies are small but present; imaizumii has a higher crown portion of C1 compared to perditus , this being comparatively stout in perditus , C-M3 tooth row is slightly shorter in perditus but zygomatic width is greater than in imaizumii ; P2 and P3 are within the tooth row in perditus but both are extruded from the tooth row internally in imaizumii . Chromosomal complement has 2n = 62 and FNa = 60.

Habitat. Forested habitats.

Food and Feeding. The Yaeyama Horseshoe Bat feeds on arthropods. Study of wing morphology showed that the species is suspected to forage in cluttered spaces. It has been recorded feeding largely on Lepidoptera, Coleoptera , Hymenoptera , and Diptera , although it also occasionally takes Orthoptera, Neuroptera, Trichoptera , and Araneae . Presence of Araneae in the diet indicates that the species probably also gleans prey off foliage.

Breeding. The Yaeyama Horseshoe Bat exhibits restricted seasonal monoestry; females form maternity colonies in May, and give birth to a single young around this time.

Activity patterns. Yaeyama Horseshoe Bats are active throughout the year, but probably hibernate through the winter with regular bouts of arousal to forage. They roost in caves, abandoned mines, and bomb shelters during the day and forage by night. Search call shape is FM/CF/ FM with a peak F recorded at 96-98 kHz on Ishigakÿima and 92-93 kHz on Iriomotejima.

Movements, Home range and Social organization. The Yaeyama Horseshoe Bat roosts in colonies and females can form maternity colonies with over 1000 individuals while raising young. This species frequently roosts with the Ryukyu Long-fingered Bat (Miniopterusfuscus) in caves.

Status and Conservation. Not assessed as a separate species on TheIUCNed List, where it is included under the Least Horseshoe Bat (pusiUus) as Least Concern. Listed as endangered in the Japanese Red List. Several caves for breeding and hibernating are known to exist on Ishigakÿima Island. However, in recent years, deforestation, roost destruction and tourism activities are creating serious problems for the island bat population. As a consequence, conservation measures need to be established immediately.

Bibliography. Ando eta /. (1980c), Chen Shiangfan eta/. (2006), Fukui eta/. (2009), Hill & Yoshiyuki (1980), Hutson, Kingston & Walston (2008), Li Gang eta/. (2006), Ohdachi eta/. (2015), WuYi, Motokawa eta/. (2012), Yoshiyuki (1989), Zhang Lin eta/. (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. perditus K. Andersen, 1918 - Yaeyama Is (Ishigakijima and Taketomi), Ryukyu Is. R.p. imaizumii Hill & Yoshiyuki, 1980 — Yaeyama Is (Iriomotejima and Kohamajima), Ryukyu Is.