Bats of the Palaearctic Region: A taxonomic and biogeographical review

Although the Palearctic is the largest biogeographic region of the World, its bat fauna consists of mere 109 species (25 genera, 8 families) of which 51 species (5 Rhinolophidae, 46 Vespertilionidae), predominantly linked to the temperate arboreal biomes, can be regarded as its core elements. These numbers are, of course, quite provisional because the knowledge on taxonomy of individual species is often rather incomplete. The patterns of geographic variation and status of local populations have been properly comprehended in eleven species only. This all biases also the current comprehension to faunal dynamics and chorologic diversity of the region. The present biogeographic analyses (based on a total of 29 800 faunal records subdivided into 112 operational biogeographic units) were thus intended to reveal the large scale biogeographic patterns and the major trends. Among others the following were particularly well marked: (1) most of the arboreal elements are characterized by the E-W Palearctic vicariance, some also with the vicariant species in the W-Palearctic eremial zone, (2) besides the gradual latitudinal decrease in species richness and diversity there is an apparent increase in both the characteristics in the latitudinal belt of 40-500 N. This is apparently because (3) the W Palearctic is essentially contributed by the Mediterranean and Afro-eremial elements, by which (4) the species richness and diversity is here much higher that in the corresponding latitudes in both the E Palearctic and Nearctic regions. (5) The tensions along the following polarities were found the most influencing factors modulating the faunal structure: (i) eremial-boreal, (ii) Oriental-Ethiopian, (iii) Mediterranean vs. non Mediterranean.The observed specificities of the Palearctic bat fauna resulted largely from (a) subsequent disappearance of the ancient groups of specialized foragers during the Neogene, (b) increasing the role of an ancient pattern of faunal arrangement centered around the unspecialized foraging (viz., slow aerial hawking), and (c) a massive adaptive divergence modifying it in favour of the groups capable of long-lasting hibernation. The resulting pattern is thus a bit strange: the Palearctic bat fauna is rather poor in comparison either with the original state or with the situation in the neighbouring Paleaotropic regions but, at the same time, it is rather modern and rich in fine modifications and newly rediscovered possibilities within the above mentioned constraints. Because of narrowing the adaptive limits due to these constraints, in the Palearctic bats, a large amount of parallel adaptations in different clades can be expected, as well as a considerable amount of cryptic variation resulting from it, particularly in those clades which succeeded to attain especially well balanced phenotypic design (M. mystacinus group, Pipistrellus, Plecotus a.o.).The paper is supplemented with an annotated checklist of all Palearctic bat species and a list of regional faunal record.