Pleistocene Vertebrate Faunas in the Ryukyu Islands: Their Migration and Extinction.
Pleistocene Vertebrate Faunas in the Ryukyu Islands: Their Migration and Extinction.
复制标题
琉球群岛更新世脊椎动物群：迁徙和灭绝。
DOI：
10.3759/tropics.10.25
复制
发表时间：
2000
期刊：
影响因子：
0.7
通讯作者：
Akio Takahashi
中科院分区：
文献类型：
--
作者：
H. Otsuka;Akio Takahashi
目前对琉球群岛地层水平的研究和对琉球群岛上脊椎动物化石的古生物学分析结果，为动物从琉球大陆迁徙到邻近岛屿的历史和年龄提供了有价值的线索和思考。迄今为止，四个诊断不同的地层水平包含晚中新世至晚更新世脊椎动物化石已在岛上划定。地质和古生物学资料表明，琉球群岛地区曾多次与亚洲大陆相连，每次陆地连接都伴随着大陆特征的陆生脊椎动物的迁徙。在这4个不同地层中发现的化石组合中，已知的2级（早更新世）化石组合出现在早更新世至中更新世琉球群下的浅海沉积中。它们被认为是上新世晚期人子洞动物群的移民（Jin & Zheng, 1998; Huang, 1998； Jin等）。（Iluang et al., 1999）和四川巫山人科动物群（Iluang et al., 1991），均位于中部地区。这个组合可能被认为是最古老的后中新世动物群，可能包括更新世化石和琉球群岛现存的特有陆生脊椎动物动物群的祖先。岛上另一个重要的陆生脊椎动物化石组合物种与琉球群内最新更新世裂缝和洞穴沉积物或同时期的地层沉积物密切相关（Irvel 4）。这些组合被认为是在过去不同的陆地连接时期从亚洲大陆迁移到岛屿的混合动物群。这一层的地界脊椎动物化石包括在更新世末期灭绝的大型哺乳动物（鹿）和巨型乌龟。然而，包括哺乳动物、两栖动物和爬行动物在内的其他动物的后代仍然生活在这些岛屿上，形成了特有的岛屿特有动物群。
Results of present studies on the stratigraphic levels and the paleontological analysis of tenestrial vertebrate fossils in the Ryukyu islands fumish valuable clues and considerations as to the history and age of animal migration from the continent to its neighboring islands. To date, four diagnostically different stratigraphic levels containing Late Miocene to latest Pleistocene vertebrate fossils have been delineated in the islands. Geotogical and paleontological data suggest that the area of the Ryukyu Islands has been repeatedly connected to the Asiatic Continent and each land connection has been followed by migration of characteristic terreshial vertebrates from the continent. Among the fossil assemblages found in these four different stratigraphic levels, those from lrvel 2 @arly Pleistocene) are known to occur in shallow marine deposits underlying the Early to Middle Pleistocene Ryukyu Group. They are considered to be immigrants from either the latest Pliocene Renzidong fauna (Jin & Zheng, 1.998; Huang, 1998; Jin et at., 1999) in Anhui Province or the Wushan hominid fauna (Iluang et al., 1991) in Sichuan Province, both located in Central China, during the second land connection. This assemblage may be regarded as the oldest post-Miocene fauna and might include the ancestors of the Pleistocene fossil and living endemic terrestrial vertebrate faunas of the Ryukyu islands. Another important species of fossil assemblage of terrestrial vertebrates in the islands is closely associated with the latest Pleistocene fissure and cave deposits developed within the Ryukyu Group or coeval tenace deposits (Irvel 4). These assemblages are considered to be mixed faunas that migrated from the Asian mainland to the islands during different periods of land connection in the past. Tenestrial vertebrate fossils from this level include large mammal (deer) and giant tortoise that became extinct at the end of the latest Pleistocene. However, descendants of other animals including mammals, amphibians and reptiles, are still living in the islands forming characteristic insular endemic fauna.