Forelimb Morphology of Bats

Abstract

Of the three mammalian orders, which we have investigated, morphological features of chiropterans are considered in the literature most completely. The structure of the musculoskeletal system of particular species and comparisons of different chiropteran groups are discussed in many studies. The earliest anatomical descriptions were already published in the second half of the nineteenth century (Humphry 1869; Macalister 1872), and the golden age of this field has fallen on the second half of the twentieth century (Vaughan 1959(Vaughan , 1966(Vaughan , 1970aJullien 1969;Kovtun 1970Kovtun , 1976Kovtun , 1977Kovtun , 1978Norberg 1970Norberg , 1972Vaughan and Bateman 1970; Walton and Walton 1970a, b;Strickler 1978;Altenbach 1979; Altenbach 1983, 1985;Arganbright 1984;Foehring and Hermanson 1984;Glass and Gannon 1994;Schlosser-Sturm and Schliemann 1995;Schliemann and Schlosser-Sturm 1999; etc.). In the twenty-first century, anatomical studies of the bat locomotorium become scarce (Lopez-González and Polaco 2001; Maniakas and Youlatos 2012). The major efforts were invested in ecological interpretations of morphological features of particular members of the order or in comparison with birds, almost neglecting comparisons with other mammals.Although in the literature dealing with the origin of chiropterans, both tree shrews and colugos are regarded as the nearest relatives and, sometimes, as hypothetical ancestors, studies devoted to the analysis of musculoskeletal system of chiropterans in comparison with members of these orders of Archonta are almost absent. Only a few solitary works are devoted to comparison of flying and gliding mammals and usually consider special cases, for example, the structure and innervation of muscles in the wing membrane of chiropterans and colugos (Thewissen and Babcock 1993) or innervation of the membrane in bats and other mammals (Kovtun 1984;Thewissen and Babcock 1991).To describe the musculature, we dissected six specimens of four bat species 3 ), and Hipposideros larvatus 4 ) of three families (Chiroptera: Pteropodidae, Rhinolophidae, and Hipposideridae). In addition, we studied selected muscles of Lavia frons 5 and Chaerephon pumilus 6 (Chiroptera: Megadermatidae, Molossidae). All specimens were provided by ZMMU.Later in the text, we present generalized descriptions based on our own dissections as well as on published data (Macalister 1872;Vaughan 1959;Norberg 1970Norberg , 1972Kovtun 1978;Strickler 1978; etc.) The joint mobility is described based on the study of the aforementioned syndesmological preparations as well as fresh corpses of bats from the Moscow Region fauna ( Myotis daubentonii, Myotis dasycneme, Plecotus auritus, and Eptesicus nilssoni) and two tropical species ( Rousettus aegyptiacus and Carollia perspicillata). In addition, the movements of the shoulder girdle elements were studied using X-ray video filming of flight of the Egyptian fruit bat ( R. aegyptiacus). To keep it within the video frame, experimenter held the bat flapping wings either by its hindlimbs or b...