Unusual chytrid-like fossils in a land plant cell from the Rhynie cherts

Abstract

Evidence of chytrid-like fungi (i.e., Chytridiomycota and forms that resemble chytrids but cannot be safely assigned) using land plants or their spores as substrate and nutritional basis is rare in the Lower Devonian Rhynie cherts. This is surprising as chytrid-like organisms were abundant in the Rhynie ecosystem and land plants were a major carbon source. A cluster of unusual eucarpic, monocentric chytrid-like thalli has recently been found in a cell of a Rhynie chert land plant. Thalli are characterized by sporangia with a conspicuously darkened discharge papilla. Pigmented discharge papillae have not yet been described in fossil chytrid-like organisms. However, it remains unknown whether these are a natural feature or an artifact. Nevertheless, this discovery is important as it expands our knowledge of the interactions between early land plants and fungi.