The diversity, distribution, ecology and reproductive biology of the New Guinean anuran amphibians are still poorly known. Recent fieldwork in the western part of New Guinea (Papua, Province of Indonesia, formerly West Irian or Irian Jaya) has documented many new species and revealed derived reproductive modes in some taxa. These strategies are all associated with the liberation of early developmental stages from permanent water. Litoria cf. havina attach comparatively few eggs on the leaves of shrubs or herbs above the water surface. Larvae of Litoria arfakiana have strongly reduced jaws, and at least some older individuals occupy semiterrestrial habitats. Oreophryne clamata deposits its eggs on leaves c. 2 m above the ground, making it the third species known to have arboreal eggs in this speciose genus. In addition to guarding terrestrial eggs, a male of Oreophryne cf. wapoga transported juveniles on its back. The same behaviour was observed in a species of Callulops (the first case in the subfamily Asterophryinae, family Microhylidae), which is here described as new to science. This new species is closely related to C. eurydactylus and was found in lower montane tropical rainforest at the base of the Wandammen Peninsula. Despite having unusually large terminal discs on the fingers and toes for its genus, it was never found climbing on vegetation. Its terrestrial eggs are probably guarded by the male parent and hatchlings are carried around by the male for some days. Through this paternal care, the offspring have a greater chance of survival than do unattended eggs and froglets, and guarding males have, in this way, a greater genetic fitness than males who do not provide this care. It may be supposed that the latter fact was chiefly responsible for the evolution of paternal care in frogs.