It is endemic to southern Brazil and only known from its type series collected in 1911 from near Casa Ypiranga (or Ipiranga) along the Curitiba–Paranaguá railway, in the Serra do Mar, Paraná state.

[3] The specific name duseni honors Per Dusén, Swedish naturalist who collected the type series.

Two male syntypes at the Swedish Museum of Natural History measure 31–33 mm (1.2–1.3 in) in snout–vent length.

[3] The type series was collected from crevices and cracks in the vertical cliffs at about 600 m (2,000 ft) above sea level.

Larval ecology is unknown, but if similar to other Cycloramphus, the larvae live on rocks in the splash zones of streams in rocky areas in and around forest.