Simpson 1900 – Asia
Type Species: Unio prolongatus Drouet, 1894
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6 Currently Recognized Taxa
1. Rectidens lingulatus lingulatus (Drouet & Chaper, 1892)
2. Rectidens lingulatus prolongatus (Drouet, 1894)
3. Rectidens sumatrensis sumatrensis (Dunker, 1852)
4. Rectidens sumatrensis gracilis (Strubell, 1897)
5. Rectidens sumatrensis pressirostris (Martens, 1900)
6. Rectidens sumatrensis perakensis (Morgan, 1885)