Okalia necopinata sp. nov. (Insecta, Coleoptera, Elmidae) from Gunung Mulu National Park in Sarawak (Malaysia)

Okalia necopinata sp. nov., from Sarawak, northwest Borneo, Malaysia, is described and illustrated along with an identifcation key. The standard barcoding fragment of the mitochondrial gene coding for cytochrome c oxidase subunit I (COI) was used together with morphological characters to delimit the taxonomic boundaries of the two known species, which live in shallow streams fowing through dense primary forests in limestone areas in Pahang (West Malaysia) and Sarawak (East Malaysia). The majority of all examined Okalia are fightless. Morphological distinguishing characters are the length of the granulated ffth elytral interval, the elytral and pronotal punctation, the aedeagal morphology, and the distal portion of the ovipositor.