Reproductive traits of the Ryukyu long-furred rat (Diplothrix
legata) on Okinawa-jima Island |
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| Authors: | Tsukasa OKANO Katsuhi NAKATA Yumiko NAKAYA Takashi NAGAMINE Manabu ONUMA |
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| Affiliation: | 1)Ecological Genetics Analysis Section, Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, 16–2 Onogawa, Tsukuba, Ibaraki 305–8506, Japan;2)Yambaru Wildlife Conservation Center, 263–1 Hiji, Kunigami, Okinawa 905–1413, Japan;3)Conservation & Animal Welfare Trust, 308–7–205 Maehara, Uruma, Okinawa 904–2235, Japan |
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| Abstract: | The Ryukyu long-furred rat, Diplothrix legata, is a large rodentdistributed only on Amami-ohshima Island, Tokuno-shima Island and Okinawa-jima Island,Japan. This animal is endangered as a result of deforestation, predation by introducedcarnivores and mortality caused by vehicles. We performed theriogenological examinationsof 32 male and 25 female Ryukyu long-furred rats carcasses collected from wild populationson northern Okinawa-jima Island from December 2005 to September 2013. Adult males hadremarkably large preputial glands. Seminiferous diameter of adult was significantly small(136 ± 28 µm, n=8) from April to August. Numerous spermatozoa wereobserved from September through February, and seminiferous diameter was significantlylarge (216 ± 27 µm, n=12) during this time in adults; testes lengthchanged in a similar pattern. These findings indicate that the mating season may occurfrom September through February. Size (body length) at sexual maturity was estimated to be>560 mm in both sexes. From observation of corpora lutea and placental scars, littersize was estimated to range from 2 to 12 (average=6, n=4). These results providefundamental knowledge that will be beneficial for in situ and exsitu conservation of this rare species. |
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| Keywords: | Diplothrix legata reproductive organ Ryukyu long-furred rat seasonal change seminiferous tubule |
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