High endemic freshwater mussel (Bivalvia: Unionida) diversity in western Borneo, with description of three new species Author Zieritz, Alexandra School of Geography, University of Noưingham, Noưingham, United Kingdom Alexandra.zieritz@noưingham.ac.uk Author Pfeiffer, John National Museum of Natural History, Smithsonian Institution, Washington, DC, United States Author Rahim, Khairul Adha A. Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia Author Prayogo, Hari Faculty of Forestry, Tanjungpura University, Pontianak, West Kalimantan, Indonesia Author Anwari, Muhammad Sofwan Faculty of Forestry, Tanjungpura University, Pontianak, West Kalimantan, Indonesia Author Diba, Farah Faculty of Forestry, Tanjungpura University, Pontianak, West Kalimantan, Indonesia Author Froufe, Elsa CIIMAR / CIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, Portugal Author Blackwell, Tabitha School of Geography, University of Noưingham, Noưingham, United Kingdom Author Hartikainen, Hanna School of Life Sciences, University of Noưingham, Noưingham, United Kingdom Author Lopes-Lima, Manuel CIBIO / InBIO-Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal text Zoological Journal of the Linnean Society 2024 201 1 15 journal article 302779 10.1093/zoolinnean/zlae076 c10f3f9e-b627-428a-9391-a5cccce91bf2 0024-4082 13738505 BC3D9F3-C30C-439C-AEB6-91446E8B1AAD Rectidens lauris Zieritz et al . , sp. nov. ( Fig. 4 ) Type locality: Sungai Rempangi (Pawan Drainage), 17 km SSW of Randau, Ketapang Regency, West Kalimantan , Indonesia . Type: Holotype , FKH_MFw_x533. Paratype , FKH_MFw_ x519, Sungai Melayu [Pawan Drainage], 18.7km SSW of Randau, Ketapang Regency, West Kalimantan , Indonesia . Material examined: Two lots: FKH_MFw_x533, FKH_MFw_x519. Diagnosis: Morphologically very similar to Rectidens sumatrensis . Description: Shell thin, elongate shell outline; dorsal margin slightly rounded; ventral margin straight; posterior slope slightly biangulate; umbo even with hinge line; periostracum, yellowish/ greenish brown. Psedocardinal teeth, long, thick, one tooth in less valve* two teeth in right valve. Lateral teeth long* curved* two in less valve* one in right valve; Nacre white* with peach tint near the umbo. Soss anatomy unavailable for study. Distribution: Known from only two localities in the Pawan drainage in West Kalimantan % Fig. 5 ). Etymology: Ŋe species is named asser the river catchment of its type locality* i.e. the Laur River basin* and the ethnic group indigenous to this area* i.e. ‘Dayak Laur’.