翼手類

We analysed the karyotype of the Eastern barbastelle, Barbastella leucomelas darjelingensis for the first time, based on the preparation from bone marrow cell of a male specimen which is collected from Omogo-Valley, Mt. Ishizuchi, Ehime Prefecture, on 17th June, 1971. The diploid number (2n) was 32 and fundamental number (FN) 50. The autosomes consisted of a series of 10 pairs of metacentric and submetacentric chromosomes graded in size from large to small, and five pairs of small acrocentric chromosomes. As to the sex chromosomes, the X chromosome was medium-sized and submetacentric, and the Y was a small acrocentric chromosome (Figs. 1 and 2). The karyotype of B. leucomelas was identical to that of B. barbastellus from Europe. It is recognized in general that little karyotypic variation is found within a given genus in bats. Our finding confirmed this understanding. With regard to the phylotaxonomic position of Barbastella, Tate (1942) has included this genus in the Pipistrelloid subgroup of the group Pipistrellini judging from the dental and cranial characters, and he has positioned the group Plecotini in the group Myotini. However, a comparison of the karyotype of Barbastella (2n=32, FN=50) with those of the Plecotini (2n=32 or 30, FN=50 or 52), as shown in Table 1, suggested that it is extremely similar to those of Plecotus (Plecotus). On the other hand, we believe that the affinity among Barbastella, the Pipistrellini and the Myotini is remote because of the considerable degree of karyotypic diversity among them. For example, in the Pipistrellini the chromosome number of Pipistrellus abramus (Pipistrelloid subgroup) is 2n=26, FN=42 and that of Vespertilio orientalis (Eptesicoid subgroup) is 2n=38, FN= 50; in the Myotini those of some species belonging to the genus Myotis are 2n=44, FN= 50. Taking these data into consideration, it is likely that Barbastella is more closely related to the genera of the Plecotini than it is to the Pipistrelloid genera of the Pipistrellini. Therefore, we support the opinion of Bovey (1949b) in that Barbastella should be excluded from the Pipistrellini and then included in the Plecotini, and agree with the proposal of Williams, Druecker and Black (1970) in that the Plecotini should be separated from the Myotini.