FUNGI FROM THE LOWER DEVONIAN RHYNIE CHERT - MYCOPARASITISM

Several examples of mycoparasitism are described from the Lower Devoni an (Siegenian) Rhynie chert. These fungal interactions include thick-w alled chlamydospores and vesicles in which epibiotic fungi are attache d to the outer surface of the spore. Other fossil spores are character ized by mycoparasites developing between the layers of the spore wall or within the lumen. The presence of callosities extending from the in ner surface of some fossil spores demonstrates that the hosts were ali ve when parasitized. This response by the mycohost is identical to tha t found in certain modern mycoparasitic symbioses involving vesicular arbuscular mycorrhizae that are parasitized by various aquatic fungi. The presence of mycoparasitism in a 400-million-year-old ecosystem und erscores the potential significance of the fungal genome early in the evolution of other organisms.