AUTHOR=Regalado Ledis , Schneider Harald , Müller Patrick , Schmidt Alexander R. 

TITLE=Character evolution of modern eupolypods supports the assignment of the fossil fern Cretacifilix fungiformis to Dryopteridaceae

JOURNAL=Frontiers in Ecology and Evolution

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2023.1162577

DOI=10.3389/fevo.2023.1162577

ISSN=2296-701X

ABSTRACT=<p>The fossil fern species <italic>Cretacifilix fungiformis</italic> from mid-Cretaceous Kachin amber from Myanmar was previously assigned to eupolypod ferns for having sporangia with a vertical annulus and sporangial stalks 2–3 cells thick, along with monolete spores with a distinct perine. However, due to the insufficient documentation of character states and the unavailability of the holotype, the proposed affiliation of this fossil to derived families of eupolypods required further study. The recent discovery of additional leaf fragments of <italic>C. fungiformis</italic> from the same amber deposit enabled us to re-evaluate the relationships of this fossil taxon. Newly documented morphological evidence corroborated its placement within the eupolypod ferns. This was achieved by evaluating identifiable features present in the fossil species through an ancestral character state reconstruction utilizing a comprehensive, time-calibrated phylogeny of eupolypod ferns. Our character state reconstruction of extant eupolypod families and genera recovered morphological similarity of <italic>Cretacifilix</italic> to the closely related genera <italic>Arachniodes</italic> and <italic>Dryopteris</italic>, supporting an assignment of this fossil genus to the species-rich family Dryopteridaceae within the Polypodiineae.</p>