著者

Kaneko Yukibumi

出版者

日本哺乳類学会

雑誌

Journal of the Mammalogical Society of Japan (ISSN:09141855)

巻号頁・発行日

vol.21, no.1, pp.1-13, 1996-06-01

被引用文献数

2 2

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A study was made of age variation in the size and enamel patterns of the third upper molar of 99 <i>Eothenomys smithii</i> specimens from Japan. No significant age variation was found in either the frequency of the patterns, or the width of the dentine confluent space between the second and the third triangles. Deep lingual reentrant folds, on the posterior loop, appear in specimens where the condylobasal length (CBL) is of 22-24 mm, then the pattern with a shallow reentrant fold increases in frequency in larger CBL classes. The depth of the inner fold showed the same tendency as the changes in the patterns. A significant association, however, between five enamel patterns and age classes, depends on classification according to CBL or body weight. This proved insignificant in five CBL classes, but significant in three CBL or body weight classes. A gradual transition in the age variation of the posterior loop patterns was found among <i>Eothenomys</i> species which have rootless molars throughout life. The simple enamel pattern form significantly increased in frequency with advancing age in <i>E. andersoni</i> and <i>E. shanseius</i>, resembling <i>Clethrionomys glareolus</i> and <i>C. rufocanus</i> ; on the other hand, in <i>E. regulus</i>, <i>E. inez</i>, <i>E. eva</i>, <i>E. chinensis</i>, <i>E. wardi</i>, <i>E. custos</i> and <i>E. proditor</i> no age variation was found on the posterior loop, thus resembling <i>Microtus pennsylvanicus</i>. <i>E. smithii</i> shows a little age variation in the enamel patterns, the variation of which is of an intermediate type.

著者

Kaneko Yukibumi

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.1, pp.31-63, 2002-06-01

被引用文献数

3 8

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I classified about 600 museum specimens of Père David's vole and examined its distribution. In a restricted area of Burma (25.70-26.13°N, 98.13-98.70°E; Myanmar, Area V), 150 individual specimens sampled during the same period could be classified into two groups on the basis of the relationship between the hind foot length (HFL) and tail length (TL): the large (L) and small (S) types. Group L was distributed at altitudes above 2460 m, whereas Group S was found below 2460 m. The distance between the incisor and third upper molar (I-M3) exceeded 14.3 mm in Group L, and was less than 15.2 mm in Group S. Except for young individuals, specimens from Groups L and S from Area V differed in two external and 14 cranial measurements. The molar pattern of the third upper molar ranged from simple to complex types, and varied both within and between Groups L (Types B, C, and D) and S (Types B and C), indicating that it is inadequate as a primary diagnostic character. The relationship between TL and HFL differentiated the groups in Areas III, IV (Yunnan Province, China), VI (India, Thailand, Vietnam, and northern Burma), and VII (the provinces of Zhejiang and Fujian in China, and Taiwan), but did not differentiate them in Areas I (the provinces of Hubei and Guizhou) or II (the provinces of Gansu and Sichuan), where histograms of I-M3 distinguished Groups L and S. Proportional likeness was represented using a ratio diagram; the lines for 11 cranial dimensions distinguished Group L from Group S, indicating that they are two distinct species. Group L was identified as Eothenomys mucronatus (Allen, 1912); it was distributed in Areas II, III, V, and VI. Group S was identified as E. melanogaster (Milne-Edwards, 1872); it was distributed in Areas I, II, IV, V, and VII. The elevations at which E. melanogaster occurred decreased from southwest to northeast, whereas no clear altitudinal tendency was seen in E. mucronatus.

著者

Kaneko Yukibumi

出版者

Mammalogical Society of Japan

雑誌

Mammal study (ISSN:13434152)

巻号頁・発行日

vol.35, no.1, pp.31-55, 2010-03-01

被引用文献数

2

著者

Kaneko Yukibumi

出版者

Mammalogical Society of Japan

雑誌

Mammal study (ISSN:13434152)

巻号頁・発行日

vol.36, no.1, pp.11-22, 2011-03-01

被引用文献数

1

著者

Kaneko Yukibumi Nakata Keisuke Saitoh Takashi STENSETH Nils Chr. BJΦRNSTAD Ottar N.

出版者

Springer-Verlag Tokyo

雑誌

Researches on population ecology (ISSN:00345466)

巻号頁・発行日

vol.40, no.1, pp.21-37, 1998-06

被引用文献数

21 66

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The biology of the grey-sided vole Clethrionomys rufocanus in Hokkaido, concerning taxonomy, morphology, phylogeny, distribution, and natural history, is reviewed. Applied issues in forest management (damage, control and census) are also historically mentioned. Although Clethrionomys rufocanus of Hokkaido was originally identified as a distinct species, Evotomys (= now Clethrionomys) bedfordiae Thomas, 1905, current literature generally refers to the grey-sided vole of Hokkaido as Clethrionomys rufocanus or as C. rufocanus bedfordiae (in vernacular name, the Bedfordユs red-backed vole). The grey-sided vole is the most common small mammal in Hokkaido. It inhabits open areas as well as forests, and mainly feeds on green plants. The grey-sided vole has a high reproductive potential; litter size: 4-7; gestation period: 18-19 days; maturation age: 30-60 days old. Although spring-born individuals usually attain sexual maturity in their summer-fall of birth, their maturation is sometimes suppressed under high densities. The breeding season is generally from April to October, but with some regional variation. The vole C. rufocanus has a rather specialized diet (folivorous), particularly during winter when it feeds on bamboo grass. Many predators specialize on the grey-sided vole in Hokkaido; even the red fox, which is a typical generalist predator, selectively takes this vole. Damage by volesユ barking used to be sever on forest plantations in Hokkaido. Censuses of small rodents have been carried out for management purpose since 1954.

著者

Kaneko Yukibumi Smeenk Chris

出版者

日本哺乳類学会

雑誌

Mammal study = The Continuation of the Journal of the Mammalogical Society of Japan (ISSN:13434152)

巻号頁・発行日

vol.21, no.2, pp.161-164, 1996-12-01

被引用文献数

1

著者

Kaneko Yukibumi

出版者

日本哺乳類学会

雑誌

Mammal study = The Continuation of the Journal of the Mammalogical Society of Japan (ISSN:13434152)

巻号頁・発行日

vol.26, no.1, pp.17-33, 2001-06-01

被引用文献数

3 5

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Thirty-eight museum specimens of the Ryukyu spiny rat, belonging to the genus <i>Tokudaia</i> Kuroda, 1943 (Rodentia, Muridae), from the islands of Amami Oshima and Okinawa, in the Ryukyu Islands (=the Nansei Islands), southern Japan, were examined and measured. Each specimen was classified into one of five age groups (I-V) determined by the wear of the three upper molars. The spiny rat of Okinawa has on average within age groups III and IV a statistically longer and wider skull and a longer molar row than that of Amami Oshima. However, neither the posterior nor the central parts of the skull length and width differ between the two islands. Against the same size of head and body length (H&BL) or incisor - the third upper molar length (I-M3), the spiny rat of Okinawa has longer I-M3 or narrower zygomatic arches than the spiny rat of Amami Oshima. The Okinawan spiny rat has a wider first upper molar (wM1≥1.9 mm), whereas that of Amami Oshima is wM1≤1.8 mm. The Okinawan spiny rat has the palatine foramen of the skull situated more posteriorly than that of Amami Oshima. These findings indicate conclusively that the spiny rat populations on the two islands of Amami Oshima and Okinawa have distinctly different morphological characteristics, in addition to having different karyotypes, and as such they should be regarded as distinct species. The spiny rat of Amami Oshima should be named as <i>Tokudaia osimensis</i> (Abe, 1933) while that of Okinawa should be known as <i>Tokudaia muenninki</i> (Johnson, 1946).