A new species in the genus Lobothallia (Megasporaceae, lichenized ascomycetes), from Margalla Hills, Pakistan, is described and illustrated here under the name Lobothallia densipruinosa. It is characterized by contiguous, clustered, densely pruinose dark olive apothecia, conidia 6-10 µm long, and large areoles and lobes. Phylogenetic analysis based on ITS-nrDNA sequencing placed our species relative to L. pruinosa. Descriptions and images of the new species are provided, as well as a key for the 21 species of Lobothallia known to the world. Keywords: Lichenized ascomycetes; Megasporaceae; molecular systematics.