New species of Cortinarius sect. Austroamericani, sect. nov., from South American Nothofagaceae forests

ABSTRACT

In this study, we document and describe the new Cortinarius section Austroamericani. Our results reveal high species diversity within this clade, with a total of 12 recognized species. Of these, only C. rufus was previously documented. Seven species are described as new based on basidiomata collections. The four remaining species are only known from environmental sequences. All examined species form ectomycorrhizal associations with species of Nothofagaceae and are currently only known from Argentinean and Chilean Patagonia. The phylogenetic analysis based on the nuc rDNA internal transcriber spacer (ITS1-5.8S-ITS2 = ITS) and partial 28S gene (28S) sequences shows that this section is related to other taxa from the Southern Hemisphere. Species in this group do not belong to subg. Telamonia, where C. rufus was initially placed. Cortinarius rufus and the newly described C. subrufus form a basal clade within sect. Austroamericani that has a weakly supported relationship with the core clade. Because the two species are morphologically similar to species from the core clade and share their distribution and Nothofagaceae associations, we include them here as part of sect. Austroamericani sensu lato (s.l.) until more material is available to refine the delimitation.

KEYWORDS:

• Agaricales
• diversity
• DNA barcoding
• ectomycorrhizal fungi
• Patagonia
• species delimitation
• southern temperate forests
• 8 new taxa

ACKNOWLEDGMENTS

We thank the Administracion de Parques Nacionales of Argentina for authorizing our collecting expeditions in Parque Nacional Nahuel Huapi and Parque Nacional Lanin under Projecto 2016/720 (to E. Nouhra). The Wildlife Conservation Society Chile in Parque Karukinka kindly authorized our investigation (C.T. and T.N.). We thank the staff at the CORD herbarium for helping to rapidly process loans to facilitate this work. We acknowledge critical logistical support and photography help during field collecting by R. Healy, F. Kuhar, G. Furci, N. Fernandez, and D. Pfister. We thank Ester Gaya for inspiring discussions on the evolution on South American Cortinarii during the preparation of the manuscript. Lastly, we would like to thank the editor and two anonymous reviewers who helped us to improve the manuscript.

Additional information

Funding

This work was supported by the US National Science Foundation grant DEB 1354802 (to M.E.S. and P.B.M.), two Bentham-Moxon Trust grants in 2016 and 2017 for field work (to T.N.), an Advanced Postdoc Mobility Fellowship from the Swiss National Science Foundation (to C.T.), and the University of Florida Institute for Food and Agricultural Sciences (IFAS) (to M.E.S.).