Additional records and new species of Hydraena Kugelann, 1794 (Insecta: Coleoptera: Hydraenidae) from Balabac and Palawan, Philippines

Abstract Three new species of the genus Hydraena Kugelann, 1794 of the Philippine Island of Palawan are described in detail, namely H. angelitofelipepunoi sp. n., H. buschietanni sp. n., and H. perpusilla sp. n., along with faunistic records of further species of the genus from previously unexplored areas of Balabac and Palawan. The genital characters of the new species are illustrated by digital line drawings. Photographs of their habitus and type localities are provided. The habitat conditions of their collection sites are assessed and implications of the usefulness of Hydraena species as monitoring organisms for the conservation of vulnerable habitats are briefly discussed. An updated checklist of the Hydraena of Greater Palawan is provided which now comprises 15 described species, of which 13 are endemic to this intra-Philippine island complex.