Age is not a problem: using modern fungal taxonomy to increase accuracy of deep-time paleoecological interpretations

Abstract

Mycopalynology is an increasingly important branch of palynology. While the utility of fungi as ecological indicators has been known for nearly 100 years, it is only in the last two decades that fungi have been embraced by paleoecologists, in part because of the difficulty in classifying fungal taxa. Identification and naming of fossil fungi are not easy tasks. The traditional school follows the scheme of naming all fungi as if they were extinct, i.e. with names ending in-ites, etc. While useful for biostratigraphy, this method is not useful for paleoecology, especially if authors do not link fossil fungal remains named as form taxa to extant taxa. The most modern approach for naming fossil fungi is to follow the modern fungal taxonomic schemes. We present a re-study of three fossil fungal taxa (Desmidiosporites stellatus Elsik 1992 nomen nudum, Foveodiporites anklevarensis Varma & Rawat 1963 and Parapotamomyces maydiformis O Keefe 2017) as an example of how important the collaborative work between mycologists and palynologists is. Desmidiosporites stellatus, rather than being a variant of entomopathogenic Desmidiospora, could be a member of ?Arthrinium a group of endophytes, pathogens or saprobes, usually isolated from soil debris, plants, etc. Foveodiporites ankelvarensis is a member of a clade of soil-inhabiting fungi. Lastly, P. maydiformis is not allied to Potamomyces, as previously thought, rather it is a member of the Botryosphaeriaceae. Of note, all three taxa occur in the Eocene of Texas, Miocene of Peru, and Holocene of Argentina.