The biogeographical history of giant earthworms of the Metaphire formosae species group (Clitellata: Megascolecidae) in Taiwan and the Ryukyu Archipelago, with the description of a new species from Yonagunijima, Southern Ryukyus
The biogeographical history of giant earthworms of the Metaphire formosae species group (Clitellata: Megascolecidae) in Taiwan and the Ryukyu Archipelago, with the description of a new species from Yonagunijima, Southern Ryukyus
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台湾和琉球群岛Metaphire formosae物种组（Clitellata：Megascolecidae）巨型蚯蚓的生物地理学历史，以及来自琉球南部与那国岛的一个新物种的描述
DOI：
10.1007/s13127-021-00529-5
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发表时间：
2021
影响因子：
1.6
通讯作者：
H. Ota
中科院分区：
文献类型：
--
作者：
Huei;Chih;H. Ota
琉球群岛的非洄游陆生动物具有高度地方性的特点，岛屿群形成了由海峡隔开的独特的生物地理区域。这种地方性是由地质事件造成的复杂的孤立历史和在数百万年的时间内通过陆桥或海洋扩散造成的。然而，对该地区陆生无脊椎动物的动物地理学知之甚少。本文首次从系统地理学的角度研究了台湾与琉球群岛之间的蚯蚓区系，并研究了该地区特有的巨蚯蚓的系统地理学和系统地理学。我们强调了强有力的证据表明，在最西端的龙岛（Yonagunijima）发现的巨型蚯蚓代表了该物种群的一个新成员，并进一步将其描述为一个新物种，系统发育分析和分化时间估计拒绝了M. dunan与其台湾姊妹种M. formosae在晚中新世8 Ma分离的假设。当时台湾和琉球地区被认为是第一次彼此分离，并与欧亚大陆分离。相反，我们的研究结果表明，台湾m.d ormosa物种群内的物种形成发生在5 Ma之后的台湾弧-大陆碰撞期间，而dunan m.d orsa在物种群多样化开始后不久就与其姊妹物种分道扬镳。在台湾，山地物种的分化遵循从北到南的模式，与岛内向南传播的弧-大陆碰撞相一致。
The non-volant terrestrial fauna of the Ryukyu Archipelago is characterized by high endemism with island groups forming distinct biogeographical regions separated by straits. This endemism has resulted from complex histories of insularization caused by geological events and dispersal through land bridges or across the sea during a timeframe of several million years. However, little is known about the zoogeography of terrestrial invertebrates in this region. We presented the first study looking into the earthworm fauna between Taiwan and the Ryukyu Archipelago under a phylogeographical context, and investigated the systematics and phylogeography of the giant earthworms in the Metaphire formosae species group endemic to this region. We highlighted strong evidence supporting that giant earthworms collected from Yonagunijima, the westernmost island of the Ryukyus, represent a new member of the species group, and further described it as a new species, Metaphire dunan sp. nov. Phylogenetic analyses and divergence time estimation rejected the hypothesis that the separation between M. dunan and its Taiwanese sister species, M. formosae , took place 8 Ma in late Miocene, when Taiwan and the Ryukyu region were supposedly first separated from each other and from the Eurasian continent. Instead, our results suggested that the speciation within the M. formosae species group occurred during the arc-continent collision in Taiwan after 5 Ma and M. dunan diverged from its sister species soon after the diversification of the species group had started. In Taiwan, the divergence of mountain-dwelling species followed a north-to-south pattern, consistent with the southward-propagating arc-continent collision on the island.