New Hypoxylon species from Martinique and new evidence on the molecular phylogeny of Hypoxylon based on ITS rDNA and β-tubulin data

Abstract

Three new species of Hypoxylon (Xylariaceae) collected from Martinique in the French Caribbean are recognised by new combinations of morphological characters. Their status as undescribed taxa was supported by secondary metabolite profiling based on High performance liquid chromatography with diode array and mass spectrometric detection (HPLC/DAD-MS) as well as by comparison of ITS and partial s-tubulin DNA sequences with related taxa. In the course of this study, the teleomorph of Nodulisporium griseobrunneum was found, and this species could be transferred to Hypoxylon. Moreover, several names in Hypoxylon are epitypified by selecting recently collected specimens from the same geographic areas as the holotypes came from. Despite the fact that our study used the hitherto most extensive taxon sampling, the phylogenetic analyses inferred from ITS and s-tubulin sequences remain contradictory to each other, and neither genealogy was found fully in agreement with phenotype-derived traits. We conclude that the right gene (or multi-gene genealogies) to reflect the phylogeny and evolution of Hypoxylon still remains to be found. For the time being, we recommend that the application of polyphasic taxonomic concepts should be continued in taxonomic studies of Hypoxylon.