Recent investigations of East Asian freshwater mussel genera Nodularia, Middendorffinaia and Inversiunio confirmed validity of the taxa, while their composition and taxonomic uncertainty concerning classification of these genera within a specific subfamily are still in question. The aim of the present study is to clarify the taxonomy and systematics of Nodularia and Middendorffinaia genera from the Russian Far East and Inversiunio from Japan, using a multiple dataset approach that combines morphology of glochidia, detailed conchological analyses with morphometry of adult and glochidial shells, and a molecular technique involving COI barcoding marker. As a result, three genetically distinct and highly divergent lineages were recognized confirming the existence of three distinct genera. The existence of five Nodularia species in Southeast Asia is shown. One of the sequences is shown to be incorrectly assigned to N. jourdyi, while in fact it also represents N. douglasiae, according to the BIN system. Existence of a single Nodularia species, namely N. douglasiae, and a single Middendorffinaia species, namely M. mongolica, in the Russian Far East is supported. We conclude that so-called comparatory species Nodularia amurensis, N. schrencki, and N. vladivostokensis are junior synonyms of the species Nodularia douglasiae; the comparatory species Middendorffinaia ussuriensis and M. dulkeitiana are junior synonyms of the species Middendorffinaia mongolica. Within Inversiunio specimens from Japan four species were recognized based on types of glochidial microsculpture of shells and genetic data. Gene sequences of Inversiunio verrucosus, endemic to the Seomjingang River basin in South Korea, and I. yanagawensis from Kyushu Island in Japan are very similar and they can be regarded as the same species, with Inversiunio verrucosus as a junior synonym of Inversiunio yanagawensis. Mussels from Honshu Island first referred to I. yanagawensis are shown to be a separate species.

中文翻译：

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来自东南亚的结节菌属、Middendorffinaia 属和 Inversiunio 属（双壳类：Unionidae）的分类地位：形态计量学、遗传学和 GenBank 数据

最近对东亚淡水贻贝属 Nodularia、Middendorffinaia 和 Inversiunio 的调查证实了该类群的有效性，而它们的组成和在特定亚科内对这些属进行分类的不确定性仍然存在问题。本研究的目的是阐明来自俄罗斯远东的 Nodularia 和 Middendorffinaia 属以及来自日本的 Inversiunio 的分类学和系统学，使用多数据集方法，该方法结合了钩端藻的形态、详细的贝壳学分析以及成年和钩端壳的形态测量学，以及涉及 COI 条形码标记的分子技术。结果，识别出三个遗传上不同且高度不同的谱系，证实了三个不同属的存在。图中显示了东南亚存在五种结节藻。根据 BIN 系统，其中一个序列被错误地分配给 N. jourdyi，而实际上它也代表 N. douglasiae。支持在俄罗斯远东地区存在单个 Nodularia 物种，即 N. douglasiae 和单个 Middendorffinaia 物种，即 M. mongolica。我们得出结论，所谓的比较种 Nodularia amurensis、N. schrencki 和 N. vladivostokensis 是 Nodularia douglasiae 物种的次要同义词；比较物种 Middendorffinaia ussuriensis 和 M. dulkeitiana 是 Middendorffinaia mongolica 物种的次要同义词。在来自日本的 Inversiunio 标本中，根据贝壳的钩针微雕类型和遗传数据，识别出四个物种。Inversiunio verrucosus的基因序列，韩国 Seomjingang 河流域特有的 I. yanagawensis 与日本九州岛的 I. yanagawensis 非常相似，可以视为同一物种，其中 Inversiunio verrucosus 是 Inversiunio yanagawensis 的低级同义词。来自本州岛的贻贝首先被称为 I. yanagawensis 被证明是一个单独的物种。