First record of Eumastacidae in Rio de Janeiro state, Brazil (Orthoptera, Caelifera)

Eutemnomastax Descamps, 1979 comprises four species and occurs in the states of Espírito Santo, Bahia, Minas Gerais, and Pernambuco. Eutemnomastax burri Descamps, 1982 is recorded for Bahia and Espírito Santo. Herein, we provide the first record of E. burri since its original description, and the first record of the genus and the family Eumastacidae from the state of Rio de Janeiro. We also provide photographs of primary types of E. burri that were destroyed in the fire at the Museu Nacional, and a distribution map for Eutemnomastax species.