Аннотация:In the spring of 1999 the author took part in the biological expedition of Joint Russian and Vietnamese Tropical center in Ke Bang limestone area (Minh Hoa district, Quan Binh province, Vietnam). The work took place from 17 March to 28 April in the vicinity of Yen Hop, Ban On and Mo-O villages. The work was composed of several aspects, including visual and audile observations, searching for day roosts, collection of bats and bat parasites. Collected specimens were fixed in 75% alcohol or prepared as skin & skull and now most of them are deposed in the collection of Zoological museum of Moscow state university.
On the observed territory we found the bat community to be composed of at least 21 bat species, representing 5 families from both suborders. The identification of some specimens is not definitive, dew to insufficient level of available manuals, and needs investigation of additional material. At least for 4 species records in Central Vietnam were made for the first time, confirmed by voucher specimens. The known distribution ranges of a number of others was extended as result of our work.
Despite that both subfamilies of Pteropodidae were represented, macroglossines (Macroglossus sobrinus and Eonycteris spelaea) were more abundant than pteropodines, which is quite uncommon. Only one specimen of the otherwise numerous Pteropodinae member — Cynopterus sphinx — was captured. Probably, this situation is connected with some local migrations. Complex landscape gives no abilities to observe a more wide area in such time ranks.
Five species of Hipposideridae were captured, one of which, Hipposideros lylei, was not previously recorded from Vietnam. Roost behavior of H. armiger, H. lylei, H. pomona and H. cineraceus was observed in two limestone caves. Hipposideros larvatus specimen, collected in primary forest, is distinctly smaller than geographic forms of this species, known to Annam.
Among the captured species of Rhinolophidae findings of Rhinolophus paradoxolophus noticeably extends it’s known distribution area to south. This unique creature was captured in primary forest in ornithological mist-net, put in relatively dense growth. All captured small Rhinolophidae represent the «ferrumequinum» group. At least three species of this group were found, identified as Rh. malayanus, Rh. thomasi and Rh. sinicus, amongst which the latter one was found in Central Vietnam for the first time. In the primary forest the most common rhinolophid species was Rh. pearsoni. The Rh. pusillus species group, common in tropical Asia, was not found.
Three individuals, observed during one week in the limestone cave near Yen Hop, were identified as Megaderma lyra. If the identification is proper, this record extends the species' known distribution in Vietnam by 200-300 km southward.
From Vespertilionidae five species were captured: Myotis siligorensis, Myotis annamiticus, Hypsugo pulveratus, Scotomanes ornatus and Murina cyclotis. In Ke Bang in the season of observations Vespertilionidae seemed to be closely connected with riparian or near riparian habitats. Capturing of female of Hypsugo pulveratus representing the first record of this species from Annam territory. Big-footed mouse-eared bats, which were relatively common on the observed territory, are representatives of new species, Myotis ammamiticus, which has closest affinities in central Himalayan mountains. The two other species of plain-nosed bats were not captured but only observed: Ia io and Scotophilus sp.
The general composition of bat fauna distinctly shows the influence upon it of limestone habitats. The ratio of vespertilionid and non-vespertilionid species of insectivorous bats, typically subequal in Old World tropics, is noticeably shifted towards the domination non-Vespertilionidae representatives. Niches of aerial foragers, as serotines and pipistrelles, are occupied by large Hipposideros and some Rhinolophus. This situation is probably connected with presence in many parts of Ke Bang (i.e. in surroundings of second camp of expedition) of only seasonal water flows, and also with karst cavities as main type of roosts, which are attractive to many of rhinolophoides, but not to Vespertilionidae. In any case, the unique bat fauna of Ke Bang limestones needs further investigation, covering more spacious territory and various seasons of year.