An overview of Antrodiella and related genera of Polyporales from the Neotropics.

The genus Antrodiella includes resupinate and pileate species of polypores with a dimitic hyphal system, small, globose to cylindrical basidiospores, absence of cystidia, tetrapolar mating system, and haplo-dikaryotic nuclear behavior. Recent studies, however, indicate that Antrodiella is highly polyphyletic, so many of its species have been transferred to other genera. This study reviews the systematic status and diversity of Antrodiella from the Neotropics based, in part, on studies of type specimens. Collections from Brazil were used for molecular analysis of nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), nuc 28S rDNA (28S), and portions of genes encoding translation elongation factor 1-α (tef1) and the second largest subunit of RNA polymerase II (rpb2). Eight genera are confirmed to include Neotropical species treated as Antrodiella in a broad sense: Aegis, Antrodiella s. str., Flaviporus, Metuloidea, Mycorrhaphium, Rickiopora, Trametopsis, and Trullella. Molecular data reveal the occurrence of two new species, described as Antrodiella trivialis, the only Neotropical species of Antrodiella s. str. known so far, and Mycorrhaphium hispidum. In addition, Antrodiella luteocontexta was found to nest in the genus Aegis, close to the Grifolaceae and Polyporaceae; therefore, the new combination Aegis luteocontexta is proposed. Comments on the eight Antrodiella-related genera as well as species with uncertain taxonomic position are provided, together with a key to their identification.