Revised taxon definition in European Cortinarius subgenus Dermocybe based on phylogeny, chemotaxonomy, and morphology

Abstract

Cortinarius (Fr.) Fr. is one of the most species-rich genera in the Agaricales (Basidiomycota). Cortinarius subgen. Dermocybe (Fr.) Trog includes brightly coloured Cortinarii with anthraquinone pigments. The chemotaxonomic approach has always been as important as classical methods for species definition of Dermocybe and helped to improve overall species concepts. However, some species concepts within this group remain unclear. We therefore address this topic based on a combined phylogenetic, morphological, and pigment-chemical approach. For this, sequence data, HPLC-MS pigment profiles and spore sizes were included were included to obtain a better resolution of taxa. The study was based on 173 recent collections and 12 type specimens. A total of 117 rDNA ITS sequences were produced from the collections in this study, 102 sequences were retrieved from databases. We could detect and clearly delimit 19 Dermocybe species occurring in central European habitats, from which 16 are discussed in detail. Additionally, we grouped the detected anthraquinone pigments into four groups. This detailed analysis of dermocyboid Cortinarius species occurring in a restricted number of habitat types confirmed our hypothesis that species diversity is much higher than currently assumed. This high diversity is blurred by too wide and incorrect species concepts of several classical species like C. croceus and C. cinnamomeus. Molecular and chemotaxonomical studies carried out together with careful phenotypical analyses resulted in a good differentiation of species. A key is presented for these taxa to allow a better identification of Cortinarius subgenus Dermocybe spp. occurring in Central Europe mainly in the alpine range.

Supplementary information: The online version contains supplementary material available at 10.1007/s11557-024-01959-z.

Keywords: Anthraquinone pigments; Central alpine range; Coniferous forests; Identification key; Integrative taxonomy.

Fig. 1

Phylogenetic relationship of European dermocyboid Cortinarius species based on a maximum likelihood tree. Maximum parsimony bootstrap support values > 80% are given on the branches; black and small grey dots on the branches represent Bayesian posterior probabilities > 0.96 and > 0.80, respectively; GenBank or voucher numbers are given behind the species’ names; type sequences are printed in bold

Fig. 1

Phylogenetic relationship of European dermocyboid Cortinarius species based on a maximum likelihood tree. Maximum parsimony bootstrap support values > 80% are given on the branches; black and small grey dots on the branches represent Bayesian posterior probabilities > 0.96 and > 0.80, respectively; GenBank or voucher numbers are given behind the species’ names; type sequences are printed in bold

Fig. 2

Pigment chromatograms of 16 dermocyboid Cortinarius species, measured at 428 nm; the retention time is printed against the height of the peaks; numbers above peaks indicate pigments, names, assigned numbers and chemical structure visible on the right; colouration of box surrounding the taxon name indicate pigment groups

Fig. 3

Correlation between pigment profiles (left) and rDNA-based ITS phylogeny (right) of different Cortinarius species; green lines indicating a highly significant correlation. Abbreviations: C.cin: C. cinnamomeus, C.fer: C. fervidus, C.had: C hadrocroceus, C.hol: C. holoxanthus, C.hur: C. huronensis, C.mal: C. malicorius, C.omi: C. ominosus, C.pel: C. pellstonianus, C.pur: C. purpureus, C.rub: C. rubrophyllus, C.san: C. sanguineus, C.vit: C. vitiosus. Solid and dotted lines indicate the level of split similarity between both dendrograms

Fig. 4

Basidiospore size of C. cinnamomeus, C. fervidus, C. hadrocroceus, C. holoxanthus, C. huronensis, C. malicorius, C. ominosus, C. purpureus, C. rubrophyllus, C. salignus, C. sanguineus, and C. vitiosus; the ellipses are placed based on scatter diagrams and contain 95% of the spore measurements of each species (n ≥ 30); x-axis: length of spores in µm; y-axis: width of spores in µm; the colours of the ellipses indicate the pigment groups; coloured dots beside the species names indicate the pigment-group

Fig. 5

European Cortinarius subgenus Dermocybe: a C. cinnamomeus (TG2010058), b C. polaris (TG2008232), c C. huronensis (TG2018100), d C. hadrocroceus (TG2022027), e C. holoxanthus (2022019), f C. croceus (TG2022099), g C. davemalochii (TG2014038), h C. incognitus (TG2005237)

Fig. 6

European Cortinarius subgenus Dermocybe: a & b C. ominosus (TG2011156, IBF20200018), c C. pellstonianus (IBF20210121), d C. fervidus (TG2010131), e C. rubrophyllus (TG2021039), f C. purpureus (TG2022152), g & h C. sanguineus var. aurantiovaginatus (TG2010095, TG2006069); schale bars = 1 cm