Rhinolophus chaseni, Sanborn, 1939

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

58 . Indochinese Horseshoe Bat

Rhinolophus chaseni

French: Rhinolophe de Chasen / German: Chasen-Hufeisennase / Spanish: Herradura de Chasen

Taxonomy. Rhinolophus chaseni Sanborn, 1939 ,

“ Pulo [= Island] Condore, off the southeast coast of Cochin-China [= southern Vietnam].”

Currendy included in the megaphyUus species group, although this is questionable, based on genetic data; further research is required, with larger sample sizes, to determine the placement of this species. Rhinolophus chaseni was previously treated as a subspecies of R bomeensis but is now recognized as a distinct species, based on genetic and morphological differences. Populations throughout much of mainland South-east Asia are attributed to this species, although Peninsular Malaysian specimens are tentatively placed in R bomeensis until the population is tested genetically. Monotypic.

Distribution. Thailand, Laos, Vietnam (including Con Son in Con Dao Is), and Cambodia.

Descriptive notes. Head-body 48-60 mm, tail 20-32 mm, ear 15- 9-22 mm, hindfoot 6- 4—10 mm, forearm 40- 7-49 mm; weight 5-7-14- 5 g. Island individuals are much smaller than those of the mainland but there is litde genetic variability between them. Pelage is uniformly dark brown to dark grayish brown dorsally, being very slighdy paler ventrally; no orange morph has been recorded. Ears are of medium size. Noseleaf has a somewhat shortened hastate lancet (nearly cuneate); connecting process is rounded; sella is relatively tall, slightly convex in front view, and lacks basal folds; intemarial cup is not expanded; horseshoe is of medium width, does not completely cover muzzle, has deep median emargination, and visible lateral leaflets. Lower lip has three mental grooves. Skull is relatively robust but small (zygomatic width larger than mastoid width), median nasal swellings are smaller and less inflated than in the Malayan Horseshoe Bat (. malayanus ), and lateral swellings are much larger. P2 is reduced but within tooth row, separating C1 and P4; P is moderate to small in size and usually completely displaced labially, allowing P2 and P4 nearly to touch.

Habitat. Recorded mainly from tropical forest habitats, both primary and secondary, at elevations from sea level up to 530 m. Also commonly found in dry dipterocarp forests and disturbed areas with agricultural fields.

Food and Feeding. Indochinese Horseshoe Bats are insectivorous. They forage by aerial-hawking and probably by gleaning from the ground or vegetation.

Breeding. Breeding season in October and females probably give birth from mid- to late April to late May. Litter size is a single young.

Activity patterns. The Indochinese Horseshoe Bat is nocturnal and probably uses primarily caves and hollow trees for day roosts, although it has also been recorded in drainage pipes. Call shape is FM/CF/FM and the peak F has been recorded at 77-5-78-5 kHz in Laos; and at 80 kHz in Tay Ninh and 102 kHz on Con Son Island in Vietnam.

Movements, Home range and Social organization. Indochinese Horseshoe Bats roost in colonies.

Status and Conservation. Not assessed on The IUCN ed List as a species separate from the Bornean Horseshoe Bat ( R. borneensis ), which is classified as Least Concern. The Indochinese Horseshoe Bat seems to have a wide distribution and is common in certain regions (e.g. southern Vietnam). However, it is possibly threatened by roost disturbance and general habitat destruction. Further research into the species’ full distribution and its ecology is needed.

Bibliography. Abramov et al. (2018), Borisenko & Kruskop (2003), Csorba et al. (2003), Dang Ngoc Can et al. (2008), rancis (2008a), Francis et al. (2010), Kruskop (2010b, 2011, 2013 a, 2014), Lim et al. (2017), Matveev (2005), Thomas et al. (2013).

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. Thailand , Laos , Vietnam (including Con Son in Con Dao Is), and Cambodia .