Genera of Inocybaceae: New skin for the old ceremony

ABSTRACT

A six-gene phylogeny of the Inocybaceae is presented to address classification of major clades within the family. Seven genera are recognized that establish a global overview of phylogenetic relationships in the Inocybaceae. Two genera—Nothocybe and Pseudosperma—are described as new. Two subgenera of Inocybe—subg. Inosperma and subg. Mallocybe—are elevated to generic rank. These four new genera, together with the previously described Auritella, Tubariomyces, and now Inocybe sensu stricto, constitute the Inocybaceae, an ectomycorrhizal lineage of Agaricales that associates with at least 23 plant families worldwide. Pseudosperma, Nothocybe, and Inocybe are recovered as a strongly supported inclusive clade within the family. The genus Nothocybe, represented by a single species from tropical India, is strongly supported as the sister lineage to Inocybe, a hyperdiverse genus containing hundreds of species and global distribution. Two additional inclusive clades, including Inosperma, Tubariomyces, Auritella, and Mallocybe, and a nested grouping of Auritella, Mallocybe, and Tubariomyces, are recovered but with marginal statistical support. Overall, the six-gene data set provides a more robust phylogenetic estimate of relationships within the family than do single-gene and single-gene-region estimates. In addition, Africa, India, and Australia are characterized by the most genera in the family, with South America containing the fewest number of genera. A total of 180 names are recombined or proposed as new in Inosperma, Mallocybe, and Pseudosperma. A key to genera of Inocybaceae is provided.

KEYWORDS:

• Agaricales
• classification
• fungi
• nomenclature
• phylogeny
• systematics
• 184 new taxa

ACKNOWLEDGMENTS

We thank Rachel Swenie and En-Jing Tian for laboratory assistance, and Joe May for his assistance with sequencing at the University of Tennessee (UT) Genomics Core. We acknowledge Marisol Sánchez-García for providing species number estimates from Index Fungorum. We thank Cathie Aime, Matt Barrett, Neale Bougher, Bart Buyck, Dennis Desjardin, Genevieve Gates, Roy Halling, Terry Henkel, Egon Horak, Brad Kropp, Ellen Larsson, Pierre-Arthur Moreau, Clark Ovrebo, C.K. Pradeep, David Ratkowsky, Martin Ryberg, Steve Trudell, and Jukka Vauras for sharing specimen information or specimens sequenced for this study. Renée Lebeuf, K. P. Deepna Latha, Neale Bougher, Terry Henkel, and Noah Siegel provided photographs. Jerry Cooper and Noah Siegel kindly shared unpublished molecular results confirming the presence of Mallocybe in New Zealand. The authors also appreciate assistance from Konstanze Bensch, Luis Alberto Parra, Shaun Pennycook, Scott Redhead, and Keith Seifert for guidance and suggestions regarding rules of nomenclature and registration of new taxa. Thomas Kuyper, Martin Ryberg, and Ricardo García-Sandoval provided reviews of an earlier version, the comments of which greatly improved this study.

Supplemental data

Supplemental data for this article can be accessed on the publisher’s Web site.

Additional information

Funding

The Daniel E. Stuntz Memorial Foundation provided support for revisionary work of North American Inocybaceae, which contributed to this study. Support was also provided by National Science Foundation (NSF) grant DEB-1733750 to Karen Hughes, Brandon Matheny, and Ron Petersen at the University of Tennessee. Esteve-Raventós wishes to acknowledge the Ministerio de Educación, Cultura y Deporte (Spain) for granting the Project CGL2017-86540-P concerning the taxonomic study of European species of Inocybe.