Tuber aztecorum sp. nov., a truffle species from Mexico belonging to the Maculatum clade (Tuberaceae, Pezizales)

Abstract. A new species of truffle, T. aztecorum, is described from central Mexico. Tuber aztecorum can be distinguished from other related Tuber species synoptically by a combination of morphological features including ascospore size, pellis cells with irregular thickness, cystidia, ascoma colour and associated host (Abies religiosa an endemic Abies species from central Mexico); sequence variation on the ITS rDNA also distinguishes T. aztecorum from related species. A phylogenetic analysis of the ITS rDNA demonstrates that T. aztecorum belongs to the Maculatum clade and is unique from other similar small, white-cream coloured Tuber species distributed in north-eastern Mexico such as T. castilloi and T. guevarai.