Petractis nodispora is described as a new species, characterized by an endolithic thallus with Trentepohlia as photobiont, immersed apothecia, 3-septate, halonate ascospores, and very distinctive multicellular conidia. Nuclear ribosomal SSU and LSU sequences show that it is closely related to P. luetkemuelleri, but its relationship to the type species of Petractis, P. clausa, is unclear.