This species is known only from the type locality, Sao Lorenco do Sul, in the state of Rio Grande do Sul, Brazil, at approximately 50m asl.
Habitat and Ecology
It occurs in a seasonally inundated habitat, in which its breeding habits are unknown, though it presumably breeds in water by larval development, like other species of its genus.
Its population status is unknown. It is known from only two specimens, which were collected in 1905. Because it was only recently removed from synonymy there have been few recent attempts to locate the species, which might explain the lack of recent records.
Rice farming is possibly a threat to its habitat.
Research to determine the current status of this species is needed. It does not occur in any protected areas.
The species was revalidated by Caramaschi and Cruz (2002).
Paulo Garcia, Magno Vicente Segalla 2004. Melanophryniscus pachyrhynus. In: IUCN 2014