Vermiconidia endohyphata sp. nov., Vermiconidia lapidea sp. nov., and Vermiconidia mendeliana sp. nov. (Mycosphaerellales, Extremaceae): novel rock-inhabiting fungi from James Ross and Tail Islands, Antarctica

Abstract Antarctica’s extreme environment represents one of the unique habitats where melanised, slow-growing, rock-inhabiting fungi (RIF) thrive. This study characterised 15 fungal strains of the genus Vermiconidia isolated from rocks on James Ross and Tail Islands in Antarctica through morphological, physiological, and multilocus phylogenetic analyses. Most strains were phenotypically similar and difficult to distinguish. However, a morphological structure not previously reported among RIF, including the genus Vermiconidia , was observed. This structure consists of terminal spherical cells with internal hyphal proliferation. The majority of strains exhibited slow growth at temperatures ranging from 0 to 25 °C, with optimal growth around 20 °C, and moderate halotolerance, with detectable growth up to 5–7% sodium chloride. Using a polyphasic approach, we propose three novel species: Vermiconidia endohyphata sp. nov., Vermiconidia lapidea sp. nov., and Vermiconidia mendeliana sp. nov. These findings expand our understanding of fungal diversity and adaptation in polar ecosystems.