This species is known from Serra do Mar in the state of São Paulo, in Brazil, from about 800m asl.
Habitat and Ecology
This species is found under, or on top of, rocks in or next to small forest streams in primary and secondary forest. It presumably has larvae that are found on rocks that are covered with a film of running water, either on exposed rocks in or next to streams, like other members of the genus.
This is a reasonably common species; however, there has been an unexplained decline over its whole range recently. It was once common in Boracéia, but has been considered locally extinct there since 1988.
There is a steel works on the coast that pollutes the water, which might be affecting local populations. The reason for the observed decline is currently unknown, but chytridiomycosis cannot be ruled out.
The range of the species includes a few protected areas. Further research into the cause of the recent declines is needed.
This species was removed from the synonymy of Cycloramphus asper by Heyer (1983).
Vanessa Verdade, Ronald Heyer 2004. Cycloramphus semipalmatus. In: IUCN 2014