A molecular and morphological re-examination of the generic limits of truffles in the tarzetta-geopyxis lineage – Densocarpa, Hydnocystis, and Paurocotylis

Truffle species within the /tarzetta-geopyxis lineage share smooth, globose, hyaline spores, but differ in the amount of convolution of hymenia in ascomata. The relationships among truffle species in this lineage have historically been confused. Phylogenetic analyses of the ITS and 28S nuclear ribosomal DNA from recently collected members of the /tarzetta-geopyxis lineage from Asia, Austral Asia, North America, and South America prompted a reinvestigation of species and generic limits in the truffle genera Hydnocystis, Paurocotylis, and Stephensia. Our analyses support emendations of Hydnocystis and Paurocotylis, abandonment of Stephensia and the resurrection of the genus Densocarpa. Nomenclatural changes include the transfer of Stephensia bombycina to Hydnocystis, the transfer of Hydnocystis singeri and Stephensia bynumii to Paurocotylis, the reinstatement of Densocarpa for Stephensia shanori and transfer of Stephensia crocea to Densocarpa. This is the first detection of the genus Paurocotylis in the Americas. We describe three new species, Hydnocystis transitoria from North America, Paurocotylis patagonica from South America, and Paurocotylis watlingii from Australia. Our work highlights the unexplored diversity, morphological plasticity, and remaining taxonomic problems among truffles in the /tarzetta-geopyxis lineage.Fil: Kumar, Leticia M.. University Of Minnesota; Estados Unidos. University of Florida; Estados UnidosFil: Smith, Matthew E.. University of Florida; Estados UnidosFil: Nouhra, Eduardo Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Orihara, Takamichi. Kanagawa Prefectural Museum of Natural History; JapónFil: Sandoval Leiva, Pablo. Biota Gestión y Consultorías Ambientales Ltda.; ChileFil: Pfister, Donald H.. Harvard University; Estados UnidosFil: McLaughlin, David J.. University Of Minnesota; Estados UnidosFil: Trappe, James M.. State University of Oregon; Estados UnidosFil: Healy, Rosanne A.. University Of Minnesota; Estados Unidos. University of Florida; Estados Unido