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Pliocene and pleistocene bats of Poland

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The fossil remains of Pliocene and Pleistocene bats from central and southern Poland have been examined, belonging to three families: Rhinolophidae, Miniopteridae and Vespertilionidae. In the material examined, 15 species of bats have been found, six of which being new: Rhinolophus kowalskii Topal, R. wenzensis sp. n., R. cf. macrorhinus Topal, R. hanaki sp. n. R. cf., variabilis Topal, R. neglectus Heller, Rhinolophus sp. (mehelyi?) (Rhinolophidae); Miniopterus approximatus sp. n. (Miniopteridae); Eptesicus kowalskii sp. n., E. mossoczyi sp. n., E. cf. serotinus (Schreber), E. nilssoni (Keyserling et Blasius), Barbastella cf. schadleri Wettstein-Westersheim, Plecotus rabederi sp. n., P. cf. abeli Wettstein-Westersheim (Vespertilionidae). The material comes from then localities. The Pliocene faunas showed a high share of thermophilous species of the families Rhinolophidae and Miniopteridae. The deterioration of the climate towards the close of the Pliocene brought about a decline in thermophilous forms. The faunas of the middle Pleistocene show a complete absence of thermophilous species, while the share of forest and boreal species increases. It has been shown that from the early Pliocene onwards, changes which appear to be evolutionary trends have continued to take place in skull structure. Some of these trends were analysed, and they were found to consist mainly in the reduction of the splanchnocranium: shortening of the palate and of the premolar toothrows (both in the maxilla and the mandible). Postdental part of the mandible becomes shorter.
We used a non-invasive TOBEC method (Total Body Electric Conductivity) to estimate lean body mass and fat content in mouse-eared bats Myotis myotis (Borkhausen, 1797) hibernating in Poznań Forts (W Poland) and in a semi-natural cave-mine Miedzianka (SE Poland). In December, fat content averaged 5.5 g in females (body mass = 29.4 g) and 5.3 g in males (body mass = 28.4 g). At the end of hibernation (April), fat content averaged 2.2 g in females (body mass = 25.6 g) and 1.4 g in males (body mass = 23.7 g). Fat content did not differ between the localities either in December or in April, but the pattern of changes of fat content was different. We calculated the rate of energy expenditure in hibernating bats using two methods, based on independent samples (fat content in first-time captured individuals) and based on paired observations (changes of fat content in re-captured individuals), and discussed problems associated with the two approaches. Both methods show that the bats need about 4.9 g of fat (191 kJ) to sustain a 165-day hibernation. However, the rate of fat usage varied considerably between the sites and hibernation phase. Although the average amount of fat remaining in April would be sufficient to support at least six more weeks of hibernation, the level of reserves was close to zero in some individuals.
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