Chaetocapnodium magnum and Chaetocapnodium polonicum from conifer resins disclose an unknown lifestyle in the Capnodiales (Dothideomycetes)

The paraphyletic order Capnodiales s. lat. was recently divided into eight orders based on phylogeny, morphology, and fungal lifestyle. As a consequence, Capnodiales s. str. was redefined to include fungi called sooty moulds, which grow on sugary exudates (honeydew) excreted by sap-feeding insects. Despite some exceptions, Capnodiales s. str. constitutes a highly specialized order comprising fungi adapted to this specific habitat.

The order includes many genera, of which one of the best studied is the genus Chaetocapnodium. To date, Chaetocapnodium has accommodated 10 species, which are strictly sooty moulds. In this study, two novel species of Chaetocapnodium are described from Poland — Chaetocapnodium magnum and Chaetocapnodium polonicum — based on morphology and multi-gene phylogenetic analyses.

Importantly, both species were isolated from resin flows of conifers, which represents a new ecological niche for the genus Chaetocapnodium as well as for the entire order Capnodiales s. str. Members of the genus Chaetocapnodium were previously reported mostly from the tropics or subtropics (exceptionally from the sub-Antarctic), and therefore they are reported from the temperate zone in Europe for the first time.