Barbourula kalimantanensis is the only member of the family Bombinatoridae occurring on the island of Borneo. The species was first described in 1978 by Iskandar in Kalimantan and, until recently, was known from only two specimens. A second species, B. busuangensis, was found in the Palawan island group of the Philippines.

Barbourula kalimantanensis is a peculiar frog. The adults reach approximately 70 mm snout-vent length. Although it belongs to an archaic family characterized by numerous primitive anatomical traits, it also displays pronounced adaptations to an aquatic lifestyle in fast-flowing streams such as not only foot but also hand webbing, a flat streamlined body, and strong hindlimbs with large foot area. The species is nocturnal, hiding beneath rocks and boulders during the day, which—combined with its restricted distribution—helps explain why so little is known about its biology.

Its reproductive mode, as well as most aspects of its ecology and physiology, remain unknown. However, new published information on the reproductive biology of B. busuangensis (see information here) provides important clues, and it is highly likely that B. kalimantanensis shares a similar reproductive mode unless future evidence indicates otherwise.