Temporal changes in the geographic distribution of two clam species Meretrix lusoria and M. petechialis along the coast of Japan and South Korea

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• 作者：Shin’ichi Sato ; Yoshitaka Kaneko ; Hiroshi Torii ; Jae-Sang Hong
• 关键词：Key wordsextant and fossil shells ; Japan ; Meretrix lusoria ; Meretrix petechialis ; shell morphology ; South Korea
• 刊名：Ocean Science Journal
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：51
• 期：3
• 页码：455-463
• 全文大小：1,663 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geosciences
  Oceanography
  Waste Water Technology, Water Pollution Control, Water Management and Aquatic Pollution
  
• 出版者：Korean Ocean Research and Development Institute (KORDI) and the Korean Society of Oceanography, co-p
• ISSN：2005-7172
• 卷排序：51

文摘

The objectives of this study were to distinguish fossil specimens of Meretrix (Bivalvia, Veneridae) using discriminant score and multivariate analysis, and to examine temporal changes in the geographical distributions of M. lusoria and M. petechialis in Japan and South Korea. Fossil shells of Meretrix were collected from Miyagi, Fukui, Aichi and Kumamoto in Japan, and Gimhae, Seosan, Siheung and Ganghwa-do in South Korea. The outside of the right valve was photographed with a digital camera, and ten characteristics of the shell morphology, such as shell height and shell length, were measured using image analysis software and a digital slide caliper. The discriminant score and multivariate analysis of the shell morphology identified all of the examined fossils as M. lusoria, while living individuals collected from the western coast of South Korea were identified as M. petechialis. These results suggest that the fossil shells excavated from the western coast of South Korea are a different species from the living individuals collected from the same areas. Radioactive carbon isotopic results revealed that the ages of the four fossil shells collected from tidal flats in Ganghwa-do ranged between 3,270 ± 30 and 1,830 ± 30 Cal BP. These results suggest that M. lusoria inhabited the western coast of South Korea until at least 2,000 years ago, but was replaced by M. petechialis during the last 2,000 years. Therefore, we propose that either M. petechialis spats were introduced artificially, or planktonic larvae migrated naturally from China to the western coast of South Korea during the last 2,000 years.