The genus Silurus, an important group of catfish, exhibits heterogeneous distribution in Eurasian freshwater systems. This group includes economically important and endangered species, thereby attracting considerable scientific interest. Despite this interest, the lack of a comprehensive phylogenetic framework impedes our understanding of the mechanisms underlying the extensive diversity found within this genus. Herein, we analyzed 89 newly sequenced and 20 previously published mitochondrial genomes (mitogenomes) from 13 morphological species to reconstruct the phylogenetic relationships, biogeographic history, and species diversity of Silurus. Our phylogenetic reconstructions identified eight clades, supported by both maximum-likelihood and Bayesian inference. Sequence-based species delimitation analyses yielded multiple molecular operational taxonomic units (MOTUs) in several taxa, including the Silurus asotus complex (four MOTUs) and Silurus microdorsalis (two MOTUs), suggesting that species diversity is underestimated in the genus. A reconstructed time-calibrated tree of Silurus species provided an age estimate of the most recent common ancestor of approximately 37.61 million years ago (Ma), with divergences among clades within the genus occurring between 11.56 Ma and 29.44 Ma, and divergences among MOTUs within species occurring between 3.71 Ma and 11.56 Ma. Biogeographic reconstructions suggested that the ancestral area for the genus likely encompassed China and the Korean Peninsula, with multiple inferred dispersal events to Europe and Central and Western Asia between 21.78 Ma and 26.67 Ma and to Japan between 2.51 Ma and 18.42 Ma. Key factors such as the Eocene-Oligocene extinction event, onset and intensification of the monsoon system, and glacial cycles associated with sea-level fluctuations have likely played significant roles in shaping the evolutionary history of the genus Silurus.
鲇属鱼类（ Silurus）是鲇鱼类中的一个重要类群，在欧亚大陆的淡水水体中呈不均匀分布模式。由于同时拥有经济物种与珍稀濒危物种，因此吸引了许多不同学科方向的生物学家对鲇属鱼类开展研究。然而，由于缺乏完整的系统发育框架，关于鲇属鱼类多样性的形成机制并未得到很好地解析。该研究结合了来自13个形态物种的89个新获得的和20个先前发表的线粒体全基因组，重建了鲇属鱼类的系统发育关系和生物地理历史，并评估其物种多样性。结果显示，最大似然树和贝叶斯树一致支持鲇属鱼类由八个主要进化分枝组成。物种界定分析在鲇复合物种（ S. asotus complex）和小背鳍鲇（ S. microdorsalis）中分别鉴定了4个和2个分子操作分类单元（MOTUs），表明鲇属鱼类的物种多样性被严重低估。时间校准树发现鲇属鱼类最近的共同祖先出现在约37.61百万年前（Ma），属内不同进化分枝之间的分化时间集中在11.56 Ma至29.44 Ma之间，种内MOTUs之间的分化时间集中在3.71 Ma至11.56 Ma之间。生物地理重建分析支持中国和朝鲜半岛可能是鲇属鱼类的祖先分布区，并认为鲇属鱼类在21.78 Ma和26.67 Ma之间发生了几次向欧洲和中、西亚的扩散事件，在2.51 Ma和18.42 Ma之间发生了多次向日本岛的扩散事件。始新世-渐新世的灭绝事件、季风气候的启动和加强、冰川旋回和与冰期相关的海平面波动等地质事件可能是鲇属鱼类物种多样性形成的重要驱动力。.
Keywords: Ancestral area estimation; Bayesian inferences; Cryptic diversity; Dispersal pathways; Maximum likelihood; Mitogenomes; Sea levels.