1. Most of the Bornean endemic freshwater mussel (Unionida) species known to date have not been recorded by science for the past 50 years or more, owing to a lack of research effort and presumed population losses.
2. This study assessed current patterns and recent changes in the diversity and distribution of freshwater mussels in north-eastern Borneo. Physical surveys and interviews were conducted at 24 sites, and anecdotal evidence for current or historical presence of mussels was collected for a further 13 sites.
3. Native species, i.e. Schepmania sp. and Khairuloconcha sahanae gen. & sp. nov., were only found in one small stream of the Kinabatangan River basin within the Gomantong Forest Reserve, whereas the non-native Sinanodonta cf. woodiana was common across the study area.
4. Molecular phylogenetics (five genes) of the native taxa, including comparative material from West Kalimantan and Sarawak, revealed: (i) the presence of a new genus with two new, rare species: Khairuloconcha lunbawangorum sp. nov. in the Limbang River basin and K. sahanae in the Kinabatangan River basin; (ii) that Khairuloconcha and Ctenodesma form the Bornean endemic tribe Ctenodesmini trib. nov.; and (iii) that Schepmania represents another Bornean endemic tribe Schepmaniini trib. nov.
5. Both Khairuloconcha gen. nov. species are known from a single stream each and are apparently restricted to forest stream habitats where they occur at very low densities. Schepmania appears to have a severely contracted range in the Kinabatangan and adjacent basins. We urgently call for full protection of the currently known sites of K. lunbawangorum and K. sahanae, and development of an action plan to save the Bornean freshwater mussel fauna.

中文翻译：

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婆罗洲特有的一个新属和两个新的稀有淡水贻贝（双壳类：Unionidae）物种受到持续栖息地破坏的威胁

1. 由于缺乏研究工作和推测的人口损失，迄今为止已知的大多数婆罗洲地方性淡水贻贝 (Unionida) 物种在过去 50 年或更长时间都没有被科学记录下来。
2. 本研究评估了婆罗洲东北部淡水贻贝的多样性和分布的当前模式和近期变化。在 24 个地点进行了实地调查和访谈，并在另外 13 个地点收集了目前或历史上存在贻贝的轶事证据。
3. 本地物种，即Schepmania sp。和Khairuloconcha sahanae gen。＆sp。11 月，仅在Gomantong森林保护区内的京那巴当岸河流域的一条小溪中发现，而非本地Sinanodonta参见。woodiana在整个研究区域都很常见。
4. 本地分类群的分子系统发育（五个基因），包括来自西加里曼丹和砂拉越的比较材料，揭示了：（i）一个新属的存在和两个新的稀有物种：Khairuloconcha lunbawangorum sp。十一月 在林梦河流域和京那巴当岸河流域的K. sahanae；(ii) Khairuloconcha和Ctenodesma形成婆罗洲地方性部落 Ctenodesmini 部落。十一月；(iii) Schepmania代表另一个婆罗洲特有部落 Schepmaniini 部落。十一月
5. 两个Khairuloconcha gen。十一月 每个物种都来自一条溪流，显然仅限于森林溪流栖息地，在那里它们以非常低的密度出现。Schepmania似乎在京那巴当岸和邻近盆地有一个严重收缩的范围。我们紧急呼吁全面保护目前已知的K. lunbawangorum和K. sahanae 遗址，并制定行动计划以拯救婆罗洲淡水贻贝动物群。