Investigation of CZEUM cultures reveals new genera and species of Cladochytriales (Cladochytriomycetes, Chytridiomycota)

Cladochytriales comprises a taxonomic order and lineage of chytrid fungi that are primarily saprobes of organic matter in aquatic and terrestrial ecosystems. The order contains species from 12 genera, though molecular confirmations of almost all type species are lacking, and many genera are considered polyphyletic. We conducted phylogenetic analyses of ribosomal RNA genes and developmental morphology of Cladochytriales isolates from the Collection of Zoosporic Eufungi at the University of Michigan and noted some strains that were distinct from described genera. In our phylogenetic analysis, Endochytriaceae represented by only one strain of Endochytrium ramosum was sister to Septochytriaceae while the incertae sedis lineage formed by the new species Thomasia carolinae was sister to Nowakowskiellaceae. Additionally, the phylogenetic relatedness of the other two new species, Dogmamyces elongatus and Allochytrium aureum, was also highly supported. A thorough revision of the order is needed because some genera, such as Catenochytridium and Nephrochytrium, remain polyphyletic or paraphyletic. In addition to indicating these problems, our updated phylogeny supports the description of two new genera and three new species and thereby begins to bring the knowledge of the Cladochytriales up to date.