A re-evaluation of Neotropical Junghuhnia s.lat. (Polyporales, Basidiomycota) based on morphological and multigene analyses.

Abstract

Junghuhnia is a genus of polypores traditionally characterised by a dimitic hyphal system with clamped generative hyphae and presence of encrusted skeletocystidia. However, recent molecular studies revealed that Junghuhnia is polyphyletic and most of the species cluster with Steccherinum, a morphologically similar genus separated only by a hydnoid hymenophore. In the Neotropics, very little is known about the evolutionary relationships of Junghuhnia s.lat. taxa and very few species have been included in molecular studies. In order to test the proper phylogenetic placement of Neotropical species of this group, morphological and molecular analyses were carried out. Specimens were collected in Brazil and used for DNA sequence analyses of the internal transcribed spacer and the large subunit of the nuclear ribosomal RNA gene, the translation elongation factor 1-α gene, and the second largest subunit of RNA polymerase II gene. Herbarium collections, including type specimens, were studied for morphological comparison and to confirm the identity of collections. The molecular data obtained revealed that the studied species are placed in three different genera. Specimens of Junghuhnia carneola represent two distinct species that group in a lineage within the phlebioid clade, separated from Junghuhnia and Steccherinum, which belong to the residual polyporoid clade. Therefore, the new genus Geesterania is proposed including two species, G. carneola comb. nov. and G. davidii sp. nov. Neotropical specimens identified as Junghuhnia nitida represent a different lineage from the European species and are described as Steccherinum neonitidum sp. nov. In addition, the new combinations Steccherinum meridionale, Steccherinum polycystidiferum and Steccherinum undigerum, as well as the new name Flaviporus tenuis, are proposed.