Studies in Gyromitra II: cryptic speciation in the Gyromitra gigas species complex; rediscovery of G. ussuriensis and G. americanigigas sp. nov.

Abstract

Taxa in the Gyromitra gigas species complex were previously studied and their taxonomy resolved. During ongoing studies in this group, cryptic speciation was discovered in G. gigas. Sequences of the ITS and LSU regions from 75 specimens were included in maximum likelihood and Bayesian phylogenetic analyses to establish species boundaries and resolve species relationships. Sequence similarity comparisons were also conducted between the two ribosomal markers and between the ITS1 and ITS2 regions. Gyromitra gigas sensu stricto and two additional species were discovered within the G. gigas clade. Gyromitra ussuriensis was rediscovered as a distinct taxon and removed from synonymy under G. gigas. It occurs in central and eastern Asia, whereas G. gigas occurs mostly in Europe but also extends into central Asia. A neotype is designated for G. ussuriensis. A new species, Gyromitra americanigigas, is described and illustrated from eastern North America. Although morphology and the LSU exhibited little variation among the three species, the ITS1 and ITS2 regions displayed similar interspeci c sequence variability around 0.5-1%, which is su cient for species identi cation at the molecular level.

Distribution of the gyromitrin mycotoxin in the lorchel family assessed by a pre-column-derivatization and ultra high-performance liquid chromatography method

“…Accepting at face value earlier reports of gyromitrin production by G. gigas sensu stricto (Viernstein et al 1980), six loss events are required to explain this pattern according to our phylogeny ( G. melaleucoides clade, last common ancestor of G. caroliniana and G. ancilis clades, and various losses in the G. gigas clade). A similar number of loss events, or one horizontal transfer and four loss events, would be required to explain this distribution according to previously published phylogenetic trees (Wang and Zhuang 2019; Miller et al 2020, 2022). On the other hand, only two horizontal transfer events could result in the observed distribution, making this the most parsimonious hypothesis.…”

“…However, this identification was based solely on its purported hefty stature and the specimen was never examined (Kubička 1966). A pattern emerges in older field guides whereby European G. gigas is flagged as toxic (references in Viernstein et al [1980] and Weber [1995]) but species in the North American G. gigas group-now known to correspond to G. korfii, G. montana, and G. americanigigas (Miller et al 2020(Miller et al , 2022-are listed as edible (references in Weber [1995]). One such source, Tylutki's Mushrooms of Idaho and the Pacific Northwest (1979), describes G. montana (listed as G. gigas) as a popular and delicious edible of the Rocky Mountains.…”

Gyromitra persicula sp. nov. (Discinaceae, Pezizales), a novel discoid Gyromitra from Northwestern North America

“…The mean length (L m ), mean width (W m ), length-width ratio (Q), and mean length-width ratio (Q m ) are also reported. Ascospore measurements include the perispore and apiculi consistent with Miller et al (2022a). Images were processed with Adobe Illustrator 2024 and Adobe Photoshop 2024 (Adobe Systems Inc., Mountain View, California).…”

“…Harmaja (1969) challenged the generic delimitation based on gross morphology and lumped these taxa together under Gyromitra, arguing that their microscopic characteristics represented a continuum-a taxonomic framework we follow here. Discinaceae species are difficult to separate with morphological analysis alone; contemporary studies utilize molecular phylogenetics in an integrative approach to resolve long-standing questions in Discinaceae taxonomy, tease apart species complexes, and describe new taxa (Miller et al 2020(Miller et al , 2022a. As part of ongoing studies concerning the gyromitrin mycotoxin in Discinaceae (Dirks et al 2023), Dr. Michael W. Beug contributed collections from Washington, USA, belonging to an unknown but locally abundant species.…”