Phylogeny and taxonomic revision of Thelonectria discophora (Ascomycota, Hypocreales, Nectriaceae) species complex

Abstract

Thelonectria discophora (Thelonectria, Nectriaceae, Hypocreales) is a conspicuous group of saprobic fungi on decaying plant material, characterized by red perithecia each with a broad mammiform (nipple-like) apex. The anamorphic state is characterized by a cylindrocarpon-like morphology, with 3?5 septate macroconidia, unicellular microconidia and chlamydospores are rarely produced in culture. In the past, T. discophora was regarded as one species with a wide geographic distribution. However, a recent study rejected the monophyly and cosmopolitanism of this species, and showed the existence of at least sixteen cryptic species based solely on molecular data. In the present paper, we revise the taxonomy of T. discophora species complex by describing twelve new species and four new combinations based on historic names. Individual diagnostic morphological characters for each species could not be identified; however, discrete morphological traits corresponding to each one of the three main groups of species were discovered. Lineages could be differentiated by average values of morphological traits as well as presence/absence of characteristic asexual propagules and colony growth at 30 C. Description, illustrations and keys for identification are provided for the recognized species.