Tropidonophis aenigmaticusTropidonophis aenigmaticus, also known commonly as the East Papuan keelback, is a species of snake in the subfamily Natricinae of the family Colubridae. The species is native to Papua New Guinea including Fergusson Island.HabitatThe preferred natural habitats of Tropidonophis aenigmaticus are freshwater wetlands, including near streams in forest, at altitudes from near sea level to.ReproductionTropidonophis aenigmaticus is oviparous.