Exposing hidden diversity by concordant genealogies and morphology-a study of the Lactifluus volemus (Russulales) species complex in Sikkim Himalaya (India)

Although Sikkim belongs to one of the Global Biodiversity Hotspots, little is known about its ectomycorrhizal fungi, and even less about the main genera of Russulales, i.e. Lactarius, Lactifluus, Multifurca and Russula. Combining a multilocus genealogical and morphological study, we aimed to document the diversity within Lactifluus volemus sensu lato of Sikkim Himalaya. We compared nuclear ITS and LSU rDNA, nuclear rpb1 and rpb2 protein-coding, and mitochondrial atp6 protein-coding genealogies to determine species boundaries. Interspecific relationships were inferred from the combined dataset. Bayesian and maximum likelihood single-locus genealogies are concordant and support recognition of six species. Three of these could be identified by unique morphological characteristics and are described as new species: L. dissitus, L. leptomerus and L. versiformis.