Allogynaspis flechtmanni n. gen., n. sp. is described from litter bordering a stream in a forested area of Itatiaia National Park in southeastern Brazil. Although it shares a number of traits with the free-living macrochelid genera Nothrholaspis and Macrholaspis, the new species presents a unique combination of characters that argues against its inclusion in either genus, or in any other recognised macrochelid genus. A dichotomous key that distinguishes Allogynaspis from related macrocheline genera is included in the text.
Keywords: Macrochelidae, Nothrholaspis, Macrholaspis, Geotrupacarus, gnathotectum, epigynal shield, sperm access system, phoresy, Acari.