Bull. nut. Hist. Mus. Land. (Zool.) 64(2): 207-21 1 



Issued 26 November 1998 



First records and a new subspecies of 

 Rhinolophus stheno (Chiroptera, 

 Rhinolophidae) from Vietnam. 



GABOR CSORBA 



. 



Department of Zoology, Hungarian Natural History Museum, Baross u. 13. H-1088 Budapest, Hungary 



PAULINA D. JENKINS 



'■'Department of Zoology, The Natural History Museum, Cromwell Road. London SW7 5BD 



Synopsis. The recently discovered populations of Rhinolophus stheno from North Vietnam, along with specimens previously 

 collected in Thailand, are described as a new subspecies. Rhinolophus stheno microglobosus. The median anterior rostral 

 swellings of the new subspecies are notably smaller than those of the nominate subspecies. A morphological and statistical 

 comparison is given between the two subspecies o\ R. stheno, and the closely related R. malayanus. 



INTRODUCTION 



Rhinolophus stheno Andersen, 1905 was originally described from 

 peninsular Malaysia. The known range of the species was later 

 extended to Thailand (Lekagul & McNeely, 1977), Sumatra and 

 Java (Corbet & Hill, 1992; Koopman, 1994) andTioman Island, off 

 the coast of Malaysia (Csorba et al., 1997). Recent expeditions to 

 Vietnam led by British and Hungarian researchers have discovered 

 the first specimens of R. stheno to be recorded from that country. 

 Comparative examination of these specimens with other populations 

 in the collections of The Natural History Museum, London revealed 

 that specimens from Vietnam were most similar to those from 

 Thailand, and that both were sufficiently different from material 

 from Malaysia, Sumatra and Java to represent an undescribed 

 subspecies. 



Andersen ( 1905) considered/?, stheno to belong to \he borneensis 

 subgroup of the simple.x-gwup of Rhinolophus, which Tate & 

 Archbold, 1939 subsequently termed the ferrumequinum-gcoup. 

 Andersen distinguished R. stheno from other members of the 

 borneensis sub-group by the much more projecting anterior nasal 

 swellings of the rostral part of the skull. Lekagul & McNeely (1977) 

 reported that R. stheno resembles R. malayanus Bonhote, 1903 but 

 that the two are separable by a set of external features (body size, 

 shape of lancet and relative proportions of the first and second 

 phalanges of the third digit). Subsequently. McFarlane & Blood 

 (1986) concluded that, although there are no reliable differences 

 between R. stheno and R. malayanus in these features, they are 

 instead distinguishable by supraorbital and rostral characters of the 

 cranium. They suggested that the general similarity of the noseleaf 

 and skull of/?, stheno and R. malayanus implied a closer relationship 

 than formerly supposed. This view was accepted by Corbet & Hill 

 (1992), who continued to group both species in the ferrumequinum 

 group, and keyed the two species on the basis of the shape and size 

 of the anterior and posterior rostral compartments. Bogdanowicz 

 (1992). in a phenetic analysis of the whole family, proposed different 

 group-level classifications for the two species (R. malayanus in the 

 megaphyllus group but R. stheno, with a question mark indicating 

 uncertainty, in the euryotis group). 



Specimens of/?, malayanus and /?. borneensis Peters, 1861 were 



"Address for correspondence. 



© The Natural History Museum, H 



also collected during the recent expeditions, confirming the pres- 

 ence of /?. borneensis in Vietnam (see Hill & Thonglongya, 1972, 

 Corbet & Hill, 1992 and discussion below). In view of the various 

 theories outlined above concerning the relationship between /?. 

 stheno and /?. malayanus, morphological comparisons and a Princi- 

 pal ComponentsAnalysis are given below between the two subspecies 

 of /?. stheno and /?. malayanus. 



MATERIALS AND METHODS 



All available specimens were included in the morphological com- 

 parisons but for the multivariate analysis, which requires the use of 

 complete sets of measurements, the reduced number of specimens is 

 given in parentheses as follows: 12 (8) specimens of /?. s. 

 microglobosus described below. 21 (13) specimens of the nominate 

 subspecies of /?. stheno (from Sumatra, Java and Malaysia) and 14 

 (11) specimens of /?. malayanus (from Thailand and Malaysia). 



External measurements, to the nearest 0. 1 mm. were taken from 

 dry and alcoholic museum specimens using digital calipers. Cranial 

 measurements, to an accuracy of 0.01 mm, were collected using 

 digital calipers and a binocular microscope. Characters for the 

 multivariate analysis included one external and nine cranial meas- 

 urements, as follows, with the abbreviation in parentheses: 



1. forearm length (FA) 



2. greatest skull length (GSL) - measured from the anterior of the 

 canine to the posteriormost part of the occiput; 



3. maxillary toothrow length (MTL) - the crown length from the 

 anterior of the upper canine (C) to the posterior of the third upper 

 molar (M3); 



4. zygomatic width (ZW) - the greatest distance across the zygoma; 



5. mastoid width (MW) - the greatest distance across the mastoid 

 region of the braincase; 



6. mandible length (ML) - the distance from the most posterior 

 portion of the articular process to the anteriormost edge of the 

 alveolus of the first lower incisor (i 1 ); 



7. lower toothrow length (LTL) - the crown length from the 

 anterior of the lower canine (c) to the posterior of the third lower 

 molar (m3); 



8. interorbital width (IW) - the least width of the interorbital 

 constriction: 



