The species was first described in 1911 by German zoologist Fritz Nieden, who studied a series of specimens collected two years prior.

It is a nocturnal species, emerging from shelters beneath boulders at night to catch prey such as smaller frogs.

The species has been listed as Endangered by the IUCN as it is threatened by habitat loss and possibly the fungal disease chytridiomycosis.

Nieden noted that this species resembles frogs in the genera Arthroleptis and Petropedetes, but cannot be placed in either genus because of significant differences.

Though the exact location where the Martienssen specimen was found is unknown, Nieden believed it is also in the Usambara Mountains.

[2] A paper published in 2005 concluded that the Usambara torrent frog was nested within a clade of Petropedetes species.

[5] Another population from the Nguru Mountains has been found to be a distinct, unnamed species of Arthroleptides in 2013 based on molecular evidence.

[6] The following cladogram shows the position of the Usambara torrent frog among its closest relatives according to Barej et al (2014):[4] A. martiensseni A. sp.

This species is largely restricted to mature forest, especially along rocky montane streams, though it can occur far from water and has been recorded in a tea estate.

In mature individuals, the skin is generally smooth, but younger frogs possess warts arranged in regularly spaced rows down their backs.

[9] A nocturnal animal, the Usambara torrent frog tends to shelter beneath large boulders near streams during the day, emerging at night to feed.

The coloration of the adult provides excellent camouflage against leaf litter, allowing it to blend in and avoid detection from predators and prey.

[5] This species lays its eggs on the wet surfaces of rocks near waterfalls and torrential streams, rather than directly in the water like many other frogs.

Although it remains common within areas with suitable habitat and the population is not severely fragmented, the extent of forest decline in its small range due to the expansion of rural settlements, logging and agriculture is rapidly reducing the amount of suitable habitat, and the siltation of streams may also affect it.

This species may also be threatened by the spread of the pathogenic fungus Batrachochytrium dendrobatidis, which causes the disease chytridiomycosis in infected amphibians and has been recorded in the closely related southern torrent frog.