Morphological discrimination of the Ryukyu spiny rat (genus Tokudaia) between the islands of Okinawa and Amami Oshima, In the Ryukyu Islands, southern Japan

( Max 2000 Items )
URI http://shark.lib.kagawa-u.ac.jp/kuir/metadata/1662
Title
Morphological discrimination of the Ryukyu spiny rat (genus Tokudaia) between the islands of Okinawa and Amami Oshima, In the Ryukyu Islands, southern Japan
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Description

Thirty-eight museum specimens of the Ryukyu spiny rat, belonging to the genus Tokudaia 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 Tokudaia osimensis (Abe, 1933) while that of Okinawa should be known as Tokudaia muenninki (Johnson, 1946).

Author
著者 Kaneko Yukibumi
著者(ヨミ) カネコ ユキブミ
著者(別表記) 金子 之史
Publication Title
Mammal Study
Volume
26
Issue
1
Start Page
17
End Page
33
Publisher
Mammalogical Society of Japan
Published Date
2001
NCID
AA11185060
Resource Type
Journal Article
Language
eng
Rights
copyright(C) 2001 日本哺乳類学会
Text Version
publisher
Set
香川大学
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