Rhinolophus rex G. M. Allen, 1923

King horseshoe bat

Rhinolophus paradoxolophus (Bourret, 1951)

Bourret’s horseshoe bat

These taxa appear to be very closely related and there has been some disagreement in the literature regarding whether or not they represent discrete species. For these reasons they are considered together here. Rhinolophus rex has previously been separated from R. paradoxolophus on the basis of small differences in external, cranial and dental measurements with the former considered to be the fractionally larger species. For example, R. paradoxolophus has a forearm length of 50.5–57 mm, R. rex 56.5–63 mm (Csorba et al., 2003). In our surveys, several bats captured in Guangxi had forearm lengths that would classify them as R. paradoxolophus, while our Yunnan bat had a forearm length that fits the measurements for R. rex. Despite these size differences, these bats called at similar call frequencies. Francis (in Eger and Fenton 2003) record- ed R. paradoxolophus at 22–25 kHz in Lao PDR, and hence it appears that the call frequencies used by R. paradoxolophus and R. rex are identical. Eger and Fenton (2003) recorded R. paradoxolophus at 43 kHz in China, but presumably measured the third harmonic of a signal with a fundamental at about 14 kHz. We consider that the small differences in body size are inadequate descriptors of taxonomic distinctiveness between R. paradoxolophus and R. rex, and given that their echolocation calls are very similar we suggest they are probably the same taxon. Rhinolophus paradoxolophus occurs at more southerly locations than R. rex, and the forms are probably best recognized as geographical races (subspecies). Because R. rex (1923) was named before R. paradoxolophus (1951) we suggest that the taxa are synonymised under the name R. rex and considered as one species. An account of the biology of R. paradoxolophus is given by Eger and Fenton (2003).

Rhinolophus rex

FA — 51.6–57.3 mm, mass — 10.8–14 g. Four males and 10 females were captured in Guangxi, Guizhou and Yunnan. Rhinolophus rex calls at a very low frequency, FMAXE 23.7–26.4 kHz, with calls dominated by the second harmonic.

Previous records from China (for R. rex): Chongqing, Guangdong, Guangxi, Guizhou, Sichuan and Yunnan (Zhang, 1997; Wang, 2003).

Ecological Notes

This species is restricted to southern provinces where it is only encountered in small numbers in caves. Echolocation calls are audible at close range to the unaided ear.