著者
Kawada Shin-ichiro Harada Masashi Obara Yoshitaka Kobayashi Shuji Koyasu Kazuhiro Oda Sen-ichi
出版者
社団法人日本動物学会
雑誌
Zoological science (ISSN:02890003)
巻号頁・発行日
vol.18, no.7, pp.1003-1010, 2001-09-20
被引用文献数
14 23

A detailed analysis was done on the karyotypes of four species of mole in the genera Euroscaptor and Mogera using a G-banding technique. All four species examined had a chromosome number of 2n = 36, as reported previously. Euroscaptor mizura and M. wogura from Aichi Prefecture had almost the same chromosome constitution and G-banding patterns. These common karyotypes were considered to be equivalent to the hypothetical ancestral karyotype of Mogera, since two distinct genera derived from an ancestor share G-banding homologies. According to this hypothesis, the karyotype of M. imaizumii might have been derived from the ancestral karyotype through pericentric inversion in one pair of acrocentrics, chromosome 11. Two geographically isolated populations of M. tokudae had different karyotypes : the Echigo population had the same karyotype as M. imaizumii, whereas the Sado population had a derivative karyotype that was able to be explained by pericentric inversions in three pairs of acrocentrics, remaining chromosome 11 as subtelocentric. Mogera wogura from South Korea differed considerably in terms of chromosome constitution from the Japanese population of M. wogura. However, we deduced that pericentric and paracentric inversions in four pairs of acrocentrics would explain the karyotype differences between the Japanese and Korean populations. Furthermore, from the morphology of chromosome 11, we can conclude that the Korean mole was derived from primitive M. wogura through four inversions, quite separately from the lineage of M. imaizumii and M. tokudae. Thus, inversion rearrangements appear to have played a major role in the chromosomal evolution of Japanese talpine moles.
著者
Sawada Isamu Koyasu Kazuhiro Shrestha Krishna Chandra
出版者
社団法人日本動物学会
雑誌
Zoological science (ISSN:02890003)
巻号頁・発行日
vol.10, no.1, pp.147-154, 1993-02-15
被引用文献数
2

Two new species of the cestode parasite, Staphylocystis (Staphylocystis) kathmanduensis sp. nov. and S. (S.) trisuliensis sp. nov. are described from the house shrews, Suncus murinus of Kathmandu and Trisuli, respectively. The former is related to, but different from S. (S. ) delicata Sawada et Koyasu, 1991 in the length and number of the rostellar hooks, and the size of the rostellum. The latter is related to, but different from S. (S. ) dsinezumi Sawada et Koyasu, 1990 in the rostellar hooks. The house shrew, Suncus murinus, one kind of the commensal mammals, are widly distributed in Asia and are found infected with a great number of different cestodes. The difference between the two cestode species infecting Suncus murinus collected respectively at Kathamandu and Trisuli is discussed according to the hosts's behavior patterns.
著者
Harada Masashi Ando Akiro Tsuchiya Kimiyuki Koyasu Kazuhiro
出版者
社団法人日本動物学会
雑誌
Zoological science (ISSN:02890003)
巻号頁・発行日
vol.18, no.3, pp.433-442, 2001-04-10
被引用文献数
4 16

Karyotypes of the greater Japanese shrew-mole, Urotrichus talpoides (Talpidae), collected from 57 localities in Japan were studied by conventional, G- and C-band staining techniques to elucidate geographical chromosomal variations, the mechanism of changes in chromosomes, and the distribution patterns of karyotypic races. Shrew-mole samples examined could be divided geographically into two slightly divergent chromosomal forms designated as the western and eastern races. These two karyotypic races had the same diploid number (34) and fundamental number (64), but they had autosomes with different makeups. A comparison of conventional karyotypes showed a distinct intraspecific variation in shape of autosomal pair no. 14 which was classified as subtelocentric in the western race and as metacentric in the eastern race. G- and C-banding analyses revealed that karyotypic variation found in no. 14 pair was involved in pericentric inversion and quantitative changes in constitutive heterochromatin. Intraspecific and geographical variation in chromosomes caused by such karyological events is rare and unique among members of the family Talpidae examined so far. Furthermore, our results demonstrated that the clear boundary between the two parapatric karyotypic races was actually located along the Kurobe-Fuji line in the central part of Honshu, but not along the Owari-Tsuruga isthmian line previously postulated by Tsuchiya (1987,1988). Zoogeographical implications of the boundary of parapatric distribution in U. talpoides are also discussed.
著者
Kawada Shin-ichiro Koyasu Kazuhiro Zholnerovskaya Elena I. ODA Sen-ichi
出版者
日本哺乳類学会
雑誌
Mammal study (ISSN:13434152)
巻号頁・発行日
vol.27, no.2, pp.107-111, 2002-12-01
被引用文献数
2 2

The upper dental formula of the Russian desman Desmana moschata (Linnaeus, 1758) (Insectivora, Talpidae) is considered based on the position of the premaxillary suture (sutura incisiva). From the lateral aspect, this suture extends to the second tooth in the tooth row. From the ventral aspect, the suture connects the common alveolus fossa of the second and third teeth in front of the second tooth on the labial edge and behind it on the lingual edge; consequently, the third tooth in the upper row appears to be derived from the maxilla. Therefore, the upper tooth formula of D. moschata may differ from the traditional fundamental dental formula of eutherian mammals (I3, C1, P4, M3), and consist of two incisors, one canine, five premolars, and three molars (I2, C1, P5, M3). This hypothetical view, however, assumes two changes, a tooth deletion in the incisor row and an addition in the premolar row. The significance of the premaxillary suture and possible pitfalls in using it to define dental formulae are discussed.
著者
Motokawa Masaharu Suzuki Hitoshi Harada Masashi Lin Liang-Kong Koyasu Kazuhiro Oda Sen-ichi
出版者
社団法人日本動物学会
雑誌
Zoological science (ISSN:02890003)
巻号頁・発行日
vol.17, no.4, pp.497-504, 2000-05-20
被引用文献数
5 7

Phylogenetic relationships among the East Asian species of the genus Crocidura (Mammalia, Insectivora, Soricidae) were inferred from the partial sequences (402 base pairs) of the mitochondrial cytochrome b gene. Six species of Crocidura and one representative of another insectivoran genus Suncus were examined. In the neighbor joining tree, four distinct lineages were recognized: C. lasiura from northeastern China and Korea, and C. dsinezumi from the main-islands of Japan; C. attenuata from Taiwan; C. watasei from the Amami and Okinawa Groups, and S. murinus from the Miyako Group; and C. suaveolens from Tsushima and Taiwan, and C. sibirica from Central Asia in Russian territory. All these lineages excluding C. lasiura and C. dsinezumi were also recognized by the maximum parsimony analysis. Clustering of C. watasei with S. murinus suggested the non-monophyly of the genus Crocidura as of the present definition. Biogeographical implications of the present results were also discussed.