Phylogenetic and morphological evidence supports the recently described <i>Tuber thracicum</i>

Truffles in the genus <i>Tuber</i> are hypogeous fungi living in symbiosis with the roots of many trees and shrubs. Within the genus <i>Tuber</i>, the Melanosporum clade includes some commercial species of great economic interest that are cultivated worldwide. At least four species of the clade have been described in Europe: <i>Tuber melanosporum</i>, <i>T. brumale</i>, <i>T. crytpobrumale</i> and <i>T. petrophilum</i>. Recent phylogenetic studies have also shown the existence of cryptic species in this clade. While analysing ascomata of <i>T. brumale</i> from Bulgaria, we found distinctive macro and micro-morphological features in some specimens. Phylogenetic analysis conducted on the internal transcribed spacer (ITS), the large subunit (LSU) rDNA and the protein kinase C like (PKC) sequences showed that these specimens form a monophyletic, well-supported taxon within the Melanosporum clade, closely related to <i>T. brumale</i> complex and <i>T. petrophilum</i>. Morphological and molecular analyses supported the recent proposal of the new species <i>T. thracicum</i>.