The new species Aspicilia malvinae is described from the Falkland Islands. It is the first species of Megasporaceae to be discovered on the islands and only the seventh to be reported from South America. It is distinguished from other species of Aspicilia by the unusual secondary metabolite chemistry (hypostictic acid) and molecular sequence data. The collections of the new species support two lichenicolous fungi: Endococcus propinquus s. lat., which is new to the Falkland Islands, and a new species of Sagediopsis with small perithecia and 3-septate ascospores c. 18–20 × 4–5 μm, which is described here as S. epimalvinae. A total of 60 new DNA sequences obtained from species of Megasporaceae (mostly Aspicilia) are also introduced.
