During field surveys in the Atlantic Forest of Southern Brazil, specimens of a poroid and pileate species of Hymenochaetaceae were found and are described as a new species, Neomensularia meridionalis. . This species is morphologically and phylogenetically (ITS and nLSU) close to Neomensularia crocitincta, , distributed in Central America, Cuba and Jamaica, but can be distinguished by its larger basidiomata, a duplex context featuring a distinct black line, and golden yellow basidiospores. Additionally, an updated identification key for Neomensularia species worldwide is provided.