The new genus, Aegis Gómez-Montoya, Rajchenb.& Robledo, is described to accommodate the new species Aegis boa based on morphological data and phylogenetic evidences (ITS -LSU rDNA).It is characterized by a particular monomitic hyphal system with thick-walled, widening, inflated and constricted generative hyphae, and allantoid basidiospores.Phylogenetically Aegis is closely related to Antrodiella aurantilaeta, both species presenting an isolated position within Polyporales into Grifola clade.The new taxon is so far known from Yungas Mountain Rainforests of NW Argentina.