Of basins, plains, and trenches: Systematics and distribution of Solenogastres (Mollusca, Aplacophora) in the Northwest Pacific
Of basins, plains, and trenches: Systematics and distribution of Solenogastres (Mollusca, Aplacophora) in the Northwest Pacific
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DOI：
10.1016/j.pocean.2019.102187
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发表时间：
2019-11-01
影响因子：
4.1
通讯作者：
Joerger, Katharina M.
中科院分区：
文献类型：
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作者：
Bergmeier, Franziska S.;Haszprunar, Gerhard;Joerger, Katharina M.
管胃动物（软体动物、无壳动物）是深海底栖软体动物的常见组成部分，但人们对它们在西北太平洋的多样性知之甚少。在这项研究中，我们分析了千岛堪察加生物多样性研究二期远古千岛堪察加海沟探险期间采集的巨蜥的系统学和分布，该探险是在之前对日本海岸浅海区域、鄂霍次克海千岛深海盆地和西北太平洋开放深海平原探险的框架内进行的。这个来自从深渊到深渊带的邻近地区的独特数据集使我们能够首次研究这个被忽视的深海空地的测深和地理分布范围。我们在这些具有分类学挑战性的无板软体动物中应用的物种描述依赖于综合方法，将骨片特征与分子分析相结合。第一个基于两个线粒体标记的分子系统发育研究揭示了与传统系统学的冲突，并表明需要修改至少两个多系家族和多系目“Cavibelonia”。总共 192 个标本可归为 60 个候选物种，这些物种呈现出令人惊讶的丰富的深海动物群，其中包括深渊深处的蜥胃动物的第一批代表。我们发现所研究的区域和深度之间的单生物比例很高，动物区系重叠很少，这表明深海和深渊巨腹动物的多样性并不完全由深海斜坡的源-汇动态决定。相反，有证据表明存在深渊来源种群，支持特有深渊物种甚至可能是深渊物种的存在。我们的分子数据拒绝将堪察加海沟视为巨蜥扩散的不可逾越的障碍，海沟两侧都存在一种物种。值得注意的是，千岛堪察加海沟的一种物种垂直分布延伸超过 6,000 米。总体而言，我们的研究使全球深海巨蜥物种数量增加了一倍多，提供了独特的深渊巨蜥动物群的首次记录，并为这些深海软体动物的分布范围提供了宝贵的见解。
Solenogastres (Mollusca, Aplacophora) form a common part of the benthic malacofauna in the deep sea, but their diversity in the Northwest Pacific is poorly understood. in this study, we analyze the systematics and distribution of Solenogastres sampled during the Kuril-Kamchatka Biodiversity Studies II expedition to the hadal Kuril-Kamchatka Trench, in the framework of previous expeditions to the shallow bathyal areas of the Japanese coast, the abyssal Kuril Basin in the Sea of Okhotsk, and the open abyssal plain of the Northwest Pacific. This unique dataset from adjacent regions extending from bathyal to hadal zones, enables us to study bathymetric and geographic distribution ranges in this neglected deep-sea Glade for the first time. Our applied species delineation in these taxonomically challenging aplacophoran molluscs relies on an integrative approach, combining scleritome characters with molecular analyses. A first molecular phylogenetic study based on two mitochondrial markers reveals conflict with traditional systematics and suggests the need to revise at least two polyphyletic families and the polyphyletic order `Cavibelonia'. In total, 192 specimens could be grouped within 60 candidate species, which present a surprisingly rich abyssal fauna and includes the first representatives of Solenogastres at hadal depths. We found a high proportion of singletons and little faunal overlap between the investigated regions and depths, suggesting that the diversity of the abyssal and hadal Solenogastres is not entirely determined by source-sink dynamics from the bathyal slope. Rather, there is evidence for abyssal source populations, supporting the presence of endemic abyssal and potentially even hadal species. Our molecular data reject the KurilKamchatka Trench as an insurmountable barrier of dispersal for Solenogastres, with one species present at both sides of the trench. Remarkably, one species from the Kuril-Kamchatka Trench shows a vertical distribution extending over more than 6,000 m. Overall, our study more than doubles the global number of solenogaster species from abyssal depths, provides first records of a unique hadal solenogaster fauna and delivers valuable insights into distribution ranges of these deep-sea molluscs.