Abstract
The family Microstigmatidae is composed of two subfamilies, Microstigmatinae and Micromygalinae, seven genera and 16 species. Micromygalinae is monotypic, comprising the species Micromygalediblemma Platnick & Forster, 1982 from Panama. A new genus, Tonton is described as a new member of the Micromygalinae. Masteriaemboaba Pedroso, Baptista & Bertani, 2015, is transferred to the new genus and six new species from Brazil are described and attributed to Tonton gen. n.: the type species, T.itabirito sp. n., T.queca sp. n., T.matodentro sp. n. and T.sapalo sp. n., all from the state of Minas Gerais; T.ipiau sp. n. from the state of Bahia and T.quiteria sp. n. from the state of Maranhão. Among the cavernicolous species, only T.itabirito sp. n. is considered troglobitic by the total absence of eyes.