Water Penny (Sclerocyphon sp.)

This small, very active dark beetle with a slightly dorso-ventrally flattened body is called "water penny" and is from the family Psephenidae. The elytra showed two narrow bands of pale specks. The pronotum which was the same colour as the elytra had a pair of short pale streaks on either side of midline arising from the posterior margin. The lateral margins had pale flecks. The elytra stopped short of the terminal abdominal segments. Head was small with relatively large closely placed eyes. Antennae were segmented.
Legs were thin with feeble tarsi.
The female lays eggs under water. Larvae are aquatic and cling to the under surfaces of rocks in turbulent water courses and scrape off algae from rocks. Adults are terrestrial and live for about 4 weeks. I was lucky to find this one by the garden lights on a warm night.