An overview of the Brazilian Atlantic Forest species of Pachythone Bates (Lepidoptera: Riodinidae), with the description of a new species and an updated checklist of Pachythonina

The taxonomy of the Brazilian Atlantic Forest endemic species belonging to the Neotropical metalmark genus Pachythone Bates, 1868 is revised. A new endemic species is described, Pachythone gagarini Dolibaina & Dias, sp. nov., based on historical specimens from a single locality in Rio de Janeiro state. Adults and genitalia of the new species are illustrated and described in detail. Pachythone palades Hewitson, (1873) and P. pasicles Hewitson, (1873), described from females and males, respectively, and regarded as two distinct species since their descriptions, are here recognized as a single species, the former being considered a junior subjective synonym of the latter (syn. nov.). Lectotypes are designated for both P. palades and P. pasicles. Pachythone sumare Callaghan, 1999, so far known from its type locality in Rio de Janeiro state, is here reported from Joinville, Santa Catarina, which extends its occurrence 700 km southwards. Lastly, an updated checklist for the recently proposed subtribe Pachythonina is given.