Gondwanan connections in Tuberaceae-Helvellaceae: Discovery of the first Gymnohydnotrya species from South America

D. PFISTER; NOUHRA E; KRAISITUDOMSOOK, NATTAPOL; MUJIC, ALIJA; HEALY, ROSANNE; TRUONG, CAMILLE

Congreso; International mycological congress; 2018

Species of Gymnohydnotrya are of ectomycorrhizal, exothecial fungi in the order Pezizales.Exothecial fungi are basically ?inside-out truffles?, i.e. their fruit bodies lack a peridium and are coveredwith a hymenium layer instead. Gymnohydnotrya species have ornamented ascospores and asci thatlack opercula. Morphologically, Gymnohydnotrya is similar to species of Hydnotrya except that theHydnotrya species typically have a peridium. Gymnohydnotrya species are also characterized by hyaline,ornamented ascospores that lack an outer spore wall. The genus was described by Zhang and Minter in1989 based on herbarium specimens from Australia. Currently, there are three recognized species inthis genus: G. australiana, G. echinulata, and G. ellipsospora. Zhang and Minter placed Gymnohydnotryain the Helvellaceae. However, a recent study showed that these species were part of a distinctmonophyletic lineage that also included Southern Hemisphere species of the epigeous genusUnderwoodia. This group was identified as the /gymnohydnotrya lineage, but no further taxonomic orphylogenetic work has addressed the systematics of this group. We recently discovered specimens ofan unknown exothecial fungus in Patagonian Nothofagus forests in South America. These fungi aremorphologically similar to taxa in the genus Gymnohydnotrya but there are no previous reports of thisgenus from South America. Morphological and molecular analyses indicate that there is at least onenovel species of Gymnohydnotrya among our collections from South America. Here we describe themorphology of this South American species and place it within a multi-locus phylogenetic frameworkthat also includes new samples of Underwoodia and Helvellaceae species. We also discuss theimplications of this work on the evolution of truffle-like fungi, the biogeography of the /gymnohynotryalineage, and the taxonomy of Helvellaceae.