The PhyloCode applied to Cintractiellales, a new order of smut fungi with unresolved phylogenetic relationships in the Ustilaginomycotina

The PhyloCode is used to classify taxa based on their relation to a most recent common ancestor as recovered from a phylogenetic analysis. We examined the first specimen of Cintractiella (Ustilaginomycotina) collected from Australia and determined its systematic relationship to other Fungi. Three ribosomal DNA loci were analysed both with and without constraint to a phylogenomic hypothesis of the Ustilaginomycotina. Cintractiella did not share a most recent common ancestor with other orders of smut fungi. We used the PhyloCode to define the Cintractiellales, a monogeneric order with four species of Cintractiella, including C. scirpodendri sp. nov. on Scirpodendron ghaeri. The Cintractiellales may have shared a most recent common ancestor with the Malasseziomycetes, but are otherwise unresolved at the rank of class.