Pycnopulvinus aurantiacus gen. et sp nov., a new sporocarp-forming member of Pucciniomycotina

An unusual fungus producing minute orange stilboid sporocarps was found on a palm leaf mid-rib in a Neotropical forest. Morphological observations could not place this collection into any previously described species or genus and, due to an absence of sexual structures, even higher level placement was uncertain. Phylogenetic analysis of a portion of the large subunit and the internal transcribed spacer of the nuclear ribosomal DNA indicated that this fungus is related to Heterogastridium pycnidioideum and belongs to Heterogastridiales, Microbotryomycetes (Pucciniomycotina). A new genus and species, Pycnopulvinus aurantiacus, are proposed here to accommodate this fungus.