Molecular phylogenetic analyses revealed a high diversity of unrecognized species of Lecanora s.l. in Brazil, with many near-cryptic species that require a combined analysis of morphology, secondary metabolites and molecular sequences for accurate delimitation. In this study, a new species of Lecanora is described which is morphologically close to L. achroa and L. helva. The new species was collected in the Guadalupe environmental protection area, located in the municipality of Barra de Sirinhaém, a mangrove region in the state of Pernambuco in the Brazilian Northeast. Lecanora parachroa sp. nov. agrees with L. achroa in morphological and anatomical features but differs in secondary chemistry, lacking usnic acid and 2′-O-methylperlatolic acid. Molecular data using the ITS barcoding marker suggest that commonly identified species in this group, including L. helva and L. leprosa, are collective taxa, each including several lineages.