Cryptic taxa within European species of Hydnellum and Phellodon revealed by combined molecular and morphological analysis

Previous studies of morphological variation in the homobasidiomycete Hyphoderma setigerum have lead to suspicions of a species complex. This study explores variation in DNA sequences from the nuclear ribosomal ITS region of 45 specimens from America, Asia, and Europe in a phylogeographic context. Based on molecular analysis, morphological studies, and crossing tests, nine preliminary taxa are shown to exist inside the species complex, and the two previously described segregate species H. subsetigerum and H. nudicephalum are confirmed. The molecular analysis shows evidence of allopatric differentiation over intercontinental distances. Only one of the nine well-supported clades has a geographic distribution spanning more than one continent, probably indicating the importance of vicariance in the evolution of this species complex. The basionym of H. setigerum, Thelephora setigera, is neotypified to fix the application of that name.