We describe and illustrate Inbiomyia azevedoi, sp. nov., the first species of Inbiomyiidae known from the Atlantic Forest in southeastern Brazil. SEM photos show that the bifurcated labella have on their ventral face rows of scalelike rasping teeth that may be used to graze on green algae, as the gut content of some specimens suggest. A reanalysis of the phylogeny of the genus using Australimyza mcalpineorum as designated outgroup and including I. azevedoi shows that all four groups of species previously proposed for the genus are monophyletic if I. anodonta is removed from the scoliostylus group. Inbiomyia anodonta and I. azevedoi are here transferred to the anemosyris group. In our results with implied weight, I. exul is sister to a clade including all other species of the genus, while the scoliostylus group appears as sister to the clade (mcalpineourum group + anemosyris group).