A framework for a phylogenetic classification in the genus Cortinarius (Basidiomycota, Agaricales) derived from morphological and molecular data

Abstract

Phylogenetic relationships in the genus Cortinarius with emphasis on European species were studied by integrating a molecular phylogenetic analysis of nuclear rDNA sequences with morphological, chemical, and ecological data. Internal transcribed spacers (ITS1 and ITS2, including 5.8S) and the D1–D2 regions of nuclear rDNA of 262 Cortinarius species including most of the recognised subgenera from Europe, South America, Australia, Tasmania, New Zealand, and Asia were sequenced and analysed by maximum likelihood and neighbour joining. Our morphological and molecular analyses showed considerable disagreement with earlier morphology-based hypotheses concerning the infrageneric delimitations in Cortinarius. We propose a new base for a more natural classification system in Cortinarius involving the taxonomic rearrangement of the species into the following major lineages that we informally designate as “clades” at this time: (1) phlegmacioid species are included in Alluti, Amarescentes, Arguti, Calochroi, Caerulescentes, Percomes, Phlegmacioides, Phlegmacium, Purpurascentes, Scauri, and Vulpini; (2) the Heterocliti clade includes species of the subgenera Leprocybe and Cystogenes ; (3) most of the Myxacium species are included in the Delibuti and Myxacium clades; (4) part of Rozites are included in the Rozites clade; (5) the north-hemispheric species of subgenus Dermocybe are included in the Dermocybe clade and part of the south-hemispheric species in the Splendidi clade; (6) part of Sericeocybe are integrated in the Anomali and Telamonia clades; (7) members of subgenus Cortinarius are assigned to the Cortinarius clade; (8) telamonioid taxa are included in the Obtusi, Renidentes, and Telamonia clades. Several Cortinarius species with peculiar patterns of morphology and basidiome coloration had isolated positions in the sequence analysis, and the evolutionary relationships among the major lineages remained unresolved. Our results suggest the convergent evolution of certain morphological traits across phylogenetically divergent lineages in Cortinarius. However, combinations of features such as pileipellis anatomy, spore shape, veil coloration, basidiome pigments, and stipe shape appear useful to circumscribe clades. Our molecular phylogenetic analysis allows insights in global geographical patterns of species distribution within the major lineages in the genus Cortinarius. The clade structure proposed here could be used as backbone for further more detailed systematic studies.

A new Cortinarius of section Calochroi (Basidiomycota, Agaricomycetes) from Mediterranean Quercus woodlands (Italy)

“…), mainly distributed across the forested northern hemisphere and formerly classified in subgenus Phlegmacium (Fr.) Trog (now regarded as an artificial polyphyletic group; Garnica et al 2003Garnica et al , 2005Garnica et al , 2009Peintner et al 2001Peintner et al , 2004Frøslev et al 2005;Harrower et al 2011). It comprises no less than 100 species occurring throughout Europe, Central and North America (Frøslev et al 2007;Garnica et al 2009Garnica et al , 2011Harrower et al 2011), characterized by conspicuous, brightly pigmented basidiomes, a dry stipe with a rounded to abruptly bulbous (marginate) base, a pileipellis with a well developed gelatinous matrix, and the presence of pigments (in pileus and stipe surface and context), which often change color with the application of KOH.…”

“…Recently seven major monophyletic lineages were recognized by Garnica et al (2009) within the /calochroid clade based on a combined multilocus phylogenetic analysis, namely Calochroi (hereafter indicated as Calochroi s.s.), Caroviolacei, Dibaphi, Elegantiores, Napi, Pseudoglaucopodes and Splendentes. Within Calochroi s.s. several species are rare and have limited distributions, often growing on calcareous soils and mainly associated with deciduous trees belonging to Betulaceae (Corylus, Carpinus, Ostrya) and Fagaceae (Castanea, Fagus, Quercus); a few species are known to be associated with Pinaceae (Garnica et al 2009).…”

“…Within Calochroi s.s. several species are rare and have limited distributions, often growing on calcareous soils and mainly associated with deciduous trees belonging to Betulaceae (Corylus, Carpinus, Ostrya) and Fagaceae (Castanea, Fagus, Quercus); a few species are known to be associated with Pinaceae (Garnica et al 2009). Most species are characterized by bright (pink-red) reactions of the basidiome surface to KOH, usually indicating the presence of sodagnitins (Sontag et al 1999;Frøslev et al 2007), lilac lamellae, presence of abundant and evident universal veil remnants on pileus and stipe, absence of anthraquinoid pigments (Gill and Steglich 1987;Frøslev et al 2007), and an eight bp length indel in the intron 2 portion of the RPB1 gene (Garnica et al 2009). …”

“…Variability and/or overlapping of many important characters, such as basidiome colors, spore dimensions, host-tree specificity, and even chemical reactions with KOH, all lead to problematic and conflicting taxonomic treatments. Recently analyses of genomic sequences (ITS, RPB1-RPB2 and D1/D2 regions of the nucLSU rDNA) have provided considerable aid (Frøslev et al 2006(Frøslev et al , 2007Ortega et al 2008;Garnica et al 2009). The number of species recognized to date based on phylogenetic analyses of gene sequences (Frøslev et al 2006(Frøslev et al , 2007Garnica et al 2009) has proved to be comparable or larger than that previously proposed even by authors such as Bidaud et al (2001) who employ a narrow morphological species concept.…”

“…Recently analyses of genomic sequences (ITS, RPB1-RPB2 and D1/D2 regions of the nucLSU rDNA) have provided considerable aid (Frøslev et al 2006(Frøslev et al , 2007Ortega et al 2008;Garnica et al 2009). The number of species recognized to date based on phylogenetic analyses of gene sequences (Frøslev et al 2006(Frøslev et al , 2007Garnica et al 2009) has proved to be comparable or larger than that previously proposed even by authors such as Bidaud et al (2001) who employ a narrow morphological species concept. However species recognized by means of a morphological species concept (morphospecies) and those recognized by applying a phylogenetic species concept (phylospecies) often do not overlap and in many cases a single name was applied to different phylogenetic species, or vice versa different names were given to the same phylogenetic species.…”