Phylogenetic analyses of Coprinopsis sections Lanatuli and Atramentarii identify multiple species within morphologically defined taxa

Sections Lanatuli and Atramentarii of the genus Coprinopsis contain some of the best known and most important agaric species, including C. cinerea and C. lagopus, yet a critical, phylogeny-based assessment of the species limits has not been carried out. Taxa have been characterized chiefly on the basis of morphological characters, which however show little discriminatory power and/or considerable overlap between several species pairs. We used ITS and LSU sequence data of 29 described taxa in Coprinopsis sections Lanatuli and Atramentarii to infer species limits and the correspondence between morphological characters and species lineages, as well as to examine the phylogenetic affinities of sections Lanatuli and Atramentarii. Our analyses recovered three large clades, implying a paraphyly for section Lanatuli. Based on morphology and clade structure, we estimate ca. 38 species in the two sections, including several potentially new taxa, three of which are described herein. Coprinopsis pachyderma, C. lagopus var. vacillans, C. acuminata, C. spelaiophila, Coprinus citrinovelatus and Cop. brunneistrangulatus were found to be synonymous with other, earlier described species. Congruent with previous mating studies, our analyses recovered multiple, morphologically indistinguishable lineages within C. lagopus, which included C. lagopus var. vacillans, an ephemeral, developmental variant. Morphological traits supporting the inferred clade structure are discussed. Three new taxa (C. fusispora, C. babosiae, C. villosa), and one new combination (C. mitraespora) are proposed.