Taxonomic status of Atelopus pachyrhynus Miranda-Ribeiro, 1920, redescription of melanophryniscus tumifrons (Boulenger, 1905), and descriptions of two new species of Melanophryniscus from the state of Santa Catarina, Brazil (Amphibia, Anura, Bufonidae)

Atelopus pachyrhynus Miranda-Ribeiro, 1920, currently a synonym of Melanophryniscus tumifrons (Boulenger, 1905), is revalidated through direct comparison of the types. The lectotype for Melanophryniscus pachyrhynus is designated, and the type-locality is restricted to São Lourenço do Sul, State of Rio Grande do Sul, Brazil. Melanophryniscus tumifrons is redescribed and its type-locality is discussed and restricted. Two new species belonging to the M. tumifrons group are described from the State of Santa Catarina, Brazil: Melanophryniscus spectabilis sp.nov. from the Municipality of Nova Teutônia, and Melanophryniscus simplex sp.nov. from Boca da Serra, Municipality of São Joaquim