Halosarpheia unicellularis sp. nov. is described from decayed attached wood of Avicennia marina collected from two mangrove sites in the Red Sea, Egypt. The ascomycete is compared with other marine taxa having ascospores with polar
unfurling appendages. It is also compared with other marine genera with oval, round or ellipsoid, hyaline, unicellular ascospores, but for which appendages have not been reported. Molecular data confirms the assignment of the fungus to Halosarpheia which forms a clade with the type species Halosarpheia fibrosa.