The Aleutian Trench, a canyon-like structure in the deep sea floor that parallels the southern fringe of the Aleutian Islands off Alaska, has only been studied by a few previous expeditions. The trench itself and the adjacent island archipelago both present potential dispersal barriers to marine species, which may shape the regional biogeography. We report new findings on the molluscan fauna of the trench and adjacent regions, from the recent “AleutBio” expedition in summer 2022 on the German research vessel Sonne. We recovered over 4300 individual mollusc specimens representing 212 identified taxa in 7 classes (all living taxonomic classes except Polyplacophora), of which 180 could be assigned to a species-level morphospecies. Highlights from our new material include: one monoplacophoran, the dumbo octopus Grimpoteuthis imperator re-collected for the first time since its description, the deepest record for the large-bodied solenogaster family Neomeniidae at 6612 m, the very rare columbariid gastropod Tropidofusus aequilonius, and new hadal records for several bivalves: Rengea murrayi, Limatula cf. vancouverensis, Neilonella abyssopacifica, Neilonella politissima, Catillopecten squamiformis, Parvamussium pacificum, and Setigloma japonica and the bivalve family Sareptidae. Comparing records from the Bering Sea (3490–3655 m), the north rim of the trench (4220–4641 m), the hadal depths of the trench bottom (6181–7287 m), and the southern rim (4790–5330 m), provides a test of potential barriers to the distributions of species across these regions. Of the species found in the Bering Sea, 63 % are also found in the broader Aleutian Trench region. Similarly, of the mollusc species found on the south rim of the trench, 68 % cross the Aleutian Trench and are found on the north rim and/or in the Bering Sea. The dispersal potential of most mollusc species is apparently not restricted by deep-sea trenches or island chains in the North Pacific.

中文翻译：

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白令海和阿留申海沟深海软体动物的分布模式


阿留申海沟是深海海底的一个峡谷状结构，与阿拉斯加附近的阿留申群岛南部边缘平行，之前只有几次探险队对此进行了研究。海沟本身和相邻的岛屿群岛都对海洋物种构成了潜在的扩散障碍，这可能会塑造区域生物地理学。我们报告了最近 2022 年夏天在德国科考船 Sonne 上进行的“AleutBio”探险中关于海沟和邻近地区软体动物群的新发现。我们回收了 4300 多个单个软体动物标本，代表 7 个类的 212 个已确定的分类群（除 Polyplacophora 外的所有现存分类类），其中 180 个可以归入物种水平的形态物种。我们新材料的亮点包括：一个 monoplacophoran，自描述以来首次重新收集的小飞象章鱼 Grimpoteuthis imperator，在 6612 m 处对大型体型螺线虫科 Neomeniidae 的最深记录，非常罕见的骨灰腹足类 Tropidofusus aequilonius，以及几种双壳类的新 hadal 记录：Rengea murrayi、Limatula cf. vancouverensis、Neilonella abyssopacifica、Neilonella politissima、 Catillopecten squamiformis、Parvamussium pacificum 和 Setigloma japonica 以及双壳类科 Sareptidae。比较白令海 （3490-3655 m）、海沟北缘 （4220-4641 m）、海沟底部的深度 （6181-7287 m） 和南缘 （4790-5330 m） 的记录，可以测试物种在这些地区分布的潜在障碍。在白令海发现的物种中，63% 也分布在更广泛的阿留申海沟地区。 同样，在海沟南缘发现的软体动物物种中，68% 穿过阿留申海沟，分布在北缘和/或白令海。大多数软体动物物种的传播潜力显然不受北太平洋深海沟或岛链的限制。