The freshwater mussels (Bivalvia: Unionida) of the biodiversity hotspot Sundaland are experiencing severe anthropogenic threats, whilst their diversity and distribution remain poorly understood. Here, we present the first modern-day data on Unionida diversity and distribution across western Borneo. Mussels were surveyed and collected in the upper Kapuas and Pawan river basins in West Kalimantan, Indonesia, and the Sambas Besar, Sarawak and Batang Sadong river basins in Sarawak, Malaysia. DNA sequencing (COI + 16S + ND1 + 18S + 28S) and morphological analyses were conducted to delineate and identify species, and reconstruct phylogenetic relationships and population genetics. Specimens belonged to six native genera and nine species, of which seven are endemic to Borneo and three are new to science, i.e. Ctenodesma mawonae Zieritz et al., sp. nov., Sarawak basin, and Ctenodesma bersinara Zieritz et al., sp. nov., and Rectidens lauris Zieritz et al., sp. nov., both Pawan basin. The monotypic genera Caudiculatus and Discomya were phylogenetically highly divergent from other known Gonideinae taxa, potentially indicating a separate tribe (for Caudiculatus) and subfamily (for Discomya). In addition, we report new records of the non-native Sinanodonta pacifica Heude, 1878 in the Batang Sadong and Kapuas river basins.

中文翻译：

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婆罗洲西部特有的淡水贻贝（双壳纲：Unionida）多样性很高，并描述了三个新物种


生物多样性热点巽他兰的淡水贻贝（双壳纲：Unionida）正遭受严重的人为威胁，而对其多样性和分布仍知之甚少。在这里，我们展示了关于婆罗洲西部尤尼尼达多样性和分布的第一份现代数据。在印度尼西亚西加里曼丹的Kapuas和Pawan河流域上游以及马来西亚沙捞越州的Sambas Besar、Sarawak和Batang Sadong河流域对贻贝进行了调查和采集。通过 DNA 测序（COI + 16S + ND1 + 18S + 28S）和形态学分析来描述和鉴定物种，并重建系统发育关系和群体遗传学。标本属于六个本地属和九个物种，其中七个是婆罗洲特有的，三个是科学上新发现的，即 Ctenodesma mawonae Zieritz et al., sp.。 nov.，砂拉越盆地，Ctenodesma bersinara Zieritz 等人，sp。 11 月，和 Rectidens lauris Zieritz 等人，sp。十一月，均为帕万盆地。单型属 Caudiculatus 和 Discomya 在系统发育上与其他已知的 Gonideinae 类群高度分化，可能表明有一个单独的部落（Caudiculatus）和亚科（Discomya）。此外，我们还报告了 1878 年在巴塘沙东 (Batang Sadong) 和卡普阿斯 (Kapuas) 河流域发现的非本土 Sinanodonta pacifica Heude 的新记录。