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北海道大学水産科学研究彙報 = Bulletin of Fisheries Sciences, Hokkaido University >
第62巻 第1号 >
胎子期におけるトド (Eumetopias jubatus) の成長様式と形態的特徴
Title: | 胎子期におけるトド (Eumetopias jubatus) の成長様式と形態的特徴 |
Other Titles: | Allometric growth and morphology of Steller sea lion fetuses |
Authors: | 條野, 真奈美1 Browse this author | 小林, 由美2 Browse this author | 浅沼, 武敏3 Browse this author →KAKEN DB | 坪田, 敏男4 Browse this author →KAKEN DB | 桜井, 泰憲5 Browse this author →KAKEN DB |
Authors(alt): | Jono, Manami1 | Kobayashi, Yumi2 | Asanuma, Taketoshi3 | Tsubota, Toshio4 | Sakurai, Yasunori5 |
Keywords: | Allometric growth | Eumetopias jubatus | External morphology | Fetus | MRI |
Issue Date: | 28-Mar-2012 |
Publisher: | 北海道大学大学院水産科学研究院 |
Journal Title: | 北海道大学水産科学研究彙報 |
Journal Title(alt): | Bulletin of Fisheries Sciences, Hokkaido University |
Volume: | 62 |
Issue: | 1 |
Start Page: | 1 |
End Page: | 7 |
Abstract: | In precocial species, fetuses often show adaptation to their particular environments. We investigated growth and morphology of 11 fetuses of Steller sea lion (Eumetopias jubatus), a highly precocial animal. The specimens were collected around Hokkaido, Japan in 2006-2008. Body length was found to increase gradually with gestational period, while body weight rapidly increased after the middle period (81-160 days) of gestation. Positive allometric growth indicating tachyauxesis was found only in the four limbs. This noteworthy limb development may indicate adaptation to postnatal movements on shore and in the water. The fur, which developed fully by birth, confirmed the importance of thermoregulation. MRI images suggested a progressive status of ossification, leading us to surmise that bone development occurs during the early (<80 days) and middle periods of gestation. We presume that shapes of internal organs are determined for the most part during early gestation, although the period will vary from one organ to another. |
Type: | bulletin (article) |
URI: | http://hdl.handle.net/2115/49086 |
Appears in Collections: | 北海道大学水産科学研究彙報 = Bulletin of Fisheries Sciences, Hokkaido University > 第62巻 第1号
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