RESUMO
The family Steccherinaceae includes genera with smooth, hydnoid, and poroid hymenophores, monomitic to dimitic hyphal systems, and generative hyphae with clamps or simple septa. Steccherinum is the largest genus in the family, with a worldwide distribution, and is characterized mainly by a dimitic hyphal system and presence of thick-walled encrusted cystidia. Species traditionally included in Steccherinum, however, have been transferred to other genera based on results of molecular phylogenetic analyses. Even though knowledge of Steccherinaceae has increased in the past few years, very little is known about the hydnoid species of the family, especially from the Neotropics. In this study, we present morphological and phylogenetic analyses on hydnoid specimens of Steccherinaceae collected in the Neotropics. Molecular data of nuc internal transcribed spacer region ITS1-5.8S-ITS rDNA (ITS) and portions of nuc 28S rDNA (28S), translation elongation factor 1-α (tef1), and the largest subunit of RNA polymerase II (rpb1) were obtained from Brazilian collections. Types and original collections were studied for morphological comparison. Samples we studied grouped in four different genera of Steccherinaceae: Cabalodontia, Etheirodon, Metuloidea, and Steccherinum. Three new neotropical species, Cabalodontia delicata, Etheirodon purpureum, and Steccherinum larssonii, are described. In addition, the new combinations Cabalodontia albofibrillosa and Metuloidea reniformis are proposed. The four genera presented in this study are compared and discussed in detail.
Assuntos
Polyporales , DNA Fúngico/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Filogenia , Polyporales/genética , RNA Ribossômico 28S , Análise de Sequência de DNARESUMO
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.