Rhinolophus macrotis Blyth, 1844

Zhang, Libiao, Jones, Gareth, Zhang, Jinshuo, Zhu, Guangjian & Parsons, Stuart, 2009, Recent surveys of bats (Mammalia: Chiroptera) from China. I. Rhinolophidae and Hipposideridae, Acta Chiropterologica 11 (1), pp. 71-88 : 77-78

Rhinolophus macrotis Blyth, 1844

Big-eared horseshoe bat

Rhinolophus siamensis Glydenstolpe, 1917

Thai horseshoe bat

We consider these taxa together because their distinctiveness from each other has long been questioned. Rhinolophus siamensis was formerly included in R. macrotis , but was recently considered as a distinct taxon on the basis of its smaller size and higher echolocation call frequency ( Francis et al., 1999; Hendrichsen et al., 2001). Indeed, Simmons (2005) treats R. siamensis as a distinct species. It was first described (as a subspecies of R. macrotis ) from north-west Thailand ( Gyldenstolpe, 1917), and is sympatric with the larger R. macrotis in Vietnam and Lao PDR (Csorba et al., 2003). A paratype specimen of R. siamensis has a forearm length of 37.1 mm, whereas R. macrotis can reach 48 mm (Csorba et al., 2003). Heller and Helversen (1989) and Kingston et al. (2000) reported that R. macrotis in Malaysia calls at 48 kHz (FA 46.5 mm and 45.5 mm, respectively), which is close to values from the large bats typical of this species in China. We have found typical R. macrotis and a smaller form (that fits with descriptions of R. siamensis ) in sympatry (even in the same cave) in Guangxi, supporting their status as separate species. Detailed analyses of genetic and call frequency variation of these taxa are currently underway (authors’ unpublished data) to clarify their taxonomic status, and to determine whether one does indeed correspond to R. siamensis and whether additional cryptic species may be present. Sun et al. (2008) identified a ‘new’ cryptic species of R. macrotis from Jianxi, though on the basis of body size and call frequency we believe that their ’new’ small species is probably R. siamensis . Wu et al. (2008) described a new, small cryptic species in the R. macrotis group from Guangdong, Guangxi and Jiangxi, which they named R. huananus . The forearm length of this bat was 39.3–43.1 mm, and hence overlapped with that found by Sun et al. (2008). Although Wu et al. (2008) argued that the body size of R. huananus was intermediate between that of R. siamensis and R. macrotis , they were not able to examine any specimens of the former. Francis (2008) gives the forearm length of R. siamensis in Thailand as 38–42 mm. We therefore believe that R. huananus may be a synonym of R. siamensis , and until further evidence is forthcoming we consider the large and small bats in the R. macrotis group in China as R. macrotis and R. siamensis , respectively.

Our criteria for separation of R. macrotis and R. siamensis are conservative because they are based on individuals where both call frequency and forearm length were recorded — we have found no overlap in either parameter between the taxa. Bats with FA> 46 mm and FMAXE <55 kHz were assigned to R. macrotis . If FA <46 mm and

FMAXE> 58 kHz then bats were assigned to R. siamensis .

Rhinolophus macrotis

FA — 46.9–49.9 mm (n = 5), mass — 8.7–9.4 g (n = 4). Two males and four females typical of R. macrotis were caught from Beijing, Guangxi and Sichuan. The echolocation calls ranged in FMAXE from 47.2–53.9 kHz.

Previous records from China (for all bats identified as R. macrotis — may include records of R. siamensis because this species was not previously considered distinct): Fujian, Guangdong, Guangxi, Guizhou, Jiangxi, Sichuan, Shaanxi, Yunnan and Zhejiang ( Zhang, 1997; Wang, 2003).

Ecological Notes

The species is relatively uncommon, and always found in small numbers. Records are widespread, extending north to Beijing from subtropical regions of China. All bats were captured in caves.

Rhinolophus siamensis

FA — 39.2–45.4 mm (n = 22), mass — 5.5–6.4 g (n = 10). Thirty-seven bats (14 ♂♂ and 23 ♀♀) could be readily assigned to this taxon, and there was no overlap with either forearm length or FMAXE of the larger R. macrotis . Echolocation calls had FMAXE ranging from 60.0–69.3 kHz (n = 22). Recorded from Fujian, Guangxi, Guizhou, Jiangxi, and Yunnan

Ecological Notes

Rhinolophus siamensis appears to be widespread in southern China, and was recorded more frequently than R. macrotis , which may extend further northwards given the new record from Beijing. The two species were sympatric (even found in the same cave) in Guangxi. Rhinolophus siamensis was previously recorded from Yunnan according to Smith and Xie (2008). All records were from caves.