Two new species of Ancyronyx Erichson, 1847 (Coleoptera: Elmidae) are described from Borneo: A. pulcherrimus (Brunei) and A. reticulatus (Sabah). Habitus views, illustrations of important characters as well as plastron structures of Ancyronyx reticulatus are presented and discussed.
Three species have been recognized in the genus Geoparnus Besuchet, 1978, all collected by sifting ground debris from tropical rainforests of Malaysia. The new species Geoparnus loebli sp. nov. is described; morphological similarities to known species G setifer Besuchet, 1978 and G rhinoceros Kodada, Jach, Ciampor Jr & (Camporova-Zat'ovicova, 2007 are discussed. Habitus of adult, male and female genitalia as well as other diagnostic characters are illustrated.