Terrestrial-aquatic wood-inhabiting ascomycete Potamomyces from the Miocene of Poland

We report fungal ascospores of Potamomyces affinities from four Miocene localities in Poland. The spores are similar to the ones known from extinct species of Potamomyces invaginatus, Potamomyces batii, and Potamomyces pontidiensis, as well as to living Potamomyces armatisporus. Living representatives of Potamomyces are saprophytic, and usually found on decaying wood. They are mainly found in a freshwater or brackish environment, and sometimes also on terrestrial, moist to damp substrates. Therefore, the species of Potamomyces can be classified as a facultative-aquatic or terrestrial- aquatic fungus. Both living and extinct species of Potamomyces prefer a tropical to subtropical, and usually humid climate as their past and recent distribution is mostly confined to the intertropical zone. Fossil record of the Potamomyces ranges from the Lower Miocene to the Holocene, covering all continents with the exception of the Antarctica. Miocene findings of Potamomyces from Poland represent the first known fossil record of this genus from Europe and confirm the warm temperate to subtropical and humid climate during Middle to Late Miocene of present Poland previously inferred from palaeobotanical investigations.

Automated summary

This study reports the discovery of fungal ascospores of Potamomyces affinities from four Miocene localities in Poland. The spores resemble those found in extinct species and a living species of Potamomyces, suggesting a preference for tropical to subtropical and humid climates. These findings also represent the first known fossil record of the genus Potamomyces from Europe.