Matang narrow-mouthed frog

''Microhyla borneensis'' , also known as the Matang narrow-mouthed frog, is a species of microhylid frog found in the Matang Range in Sarawak, Borneo. It was once the smallest known frog from the Old World . Adult males of this species have a snout-vent length of 10.6–12.8 mm . Tadpoles measure just 3 mm.