Lichenostigma is a genus of fungi in the family Phaeococcomycetaceae. It includes several species which are lichenicolous (i.e. parasitic on lichens).[1] The genus was circumscribed in 1983 by the Austrian mycologist Josef Hafellner, with Lichenostigma maureri assigned as the type species.
The fossil history of Lichenostigma provides insights into its ancient origins and long-standing ecological relationships. Discoveries from European Paleogene amber have identified two fossil specimens of Lichenostigma associated with the crustose lichen genus Ochrolechia. These fossils date back approximately 34 million years, to the uppermost Eocene. The presence of Lichenostigma in these amber inclusions confirms that both the genus and its specialised parasitic association with Ochrolechia were already well-established during this period. The fossilised Lichenostigma specimens have conidiomata and ascomata (specialised structures to produce asexual and sexual spores, respectively) that are morphologically similar to those of modern species, demonstrating the evolutionary continuity of these lichenicolous fungi. This discovery not only pushes back the minimum age of the genus Lichenostigma but also provides calibration points for phylogenetic studies.
The identification of Lichenostigma in amber fossils marks a significant advancement in paleomycology, particularly regarding the fossil record of lichenicolous fungi. Prior to these findings, evidence of ancient lichen-associated microfungi was limited to more general and likely saprotrophic associations. The Lichenostigma fossils, however, represent the first concrete evidence of mycoparasitic relationships in the fossil record, highlighting the ecological importance of these interactions.
, Species Fungorum (in the Catalogue of Life) accepts 30 species of Lichenostigma.