Heppia arenacea M. Schultz and Lempholemma polycarpum M. Schultz are described as new and placed in the Lichinaceae. Heppia arenacea occurs in soil-crust communities in southern Yemen and on Socotra. It colonizes both calcareous soil-crusts over limestone as well as soils originating from basaltic rocks. The sand-coloured, squamulose thallus, the erumpent, dark red apothecia and the incorporation of soil material into the thallus are diagnostic characters. Lempholemma polycarpum occurs on inclined limestone boulders in south-eastern Yemen. It is characterized by an umbilicate-lobate thallus with radiating, tongue-shaped, furcate lobes which bear numerous, small, immersed apothecia with punctiform discs.

The systematic position of the lichen genus Heppia in the order Lichinales was investigated. 18S rDNA sequence data were analyzed using a Bayesian approach to infer phylogeny using Markov chain Monte Carlo methods. The Lichinales are divided at family level into the sister groups Lichinaceae and Peltulaceae. The genus Heppia forms a highly supported clade in the family Lichinaceae. It is shown that the genus Heppia is morphologically well circumscribed within the Lichinaceae. As a nomenclatural consequence, the family name Heppiaceae is placed into synonymy under the older name Lichinaceae.