Borneo Narrow-mouthed Frog
Microhyla malang was classified under the name of M. borneenis for many decades, and the type specimen has now been assigned to what was formerly known as M. nepenthicola. We adopt the taxonomic amendments here for formal reasons, not necessarily endorsing this view.
Microhyla malang is a locally common species of the forest floor in primary or secondary rainforest. Size up to 25 mm snout-vent length in females, males smaller.
Whenever they can, these frogs sit covered under leaf litter and will dart out with huge jumps when disturbed.
Males congregate around pools and form choruses. At dusk, a single male my start a chorus with a series of pleasantly "crackling" notes. More and more other males join the chorus and after a minute or so it ceases, only to start over again after a break of variable length.
Microhyla borneensis reproduces in temporary stagnant pools of various sizes and depths. Tadpoles are mid water column suspension feeders. The mouth is terminal. They lack keratinized mouthparts. The spiracle is medially positioned on the belly. The coloration is characteristic and includes among other features (see image) a white spot and dark cross band at the posterior third of the tail. The tail ends in a sharp, thin flagellum.
If undisturbed tadpoles hover almost motionless in the water column, softly maneuvering by beats of the tail flagellum. At night, we saw them more frequently close to the water surface than during the day.
Tadpoles are fragile and reach a maximum total length of ca. 22 mm.