Doctoral defence: Anton Savchenko “Taxonomic studies in Dacrymycetes: Cerinomyces and allied taxa”

On 20 February at 10:15 Anton Savchenko will defend his doctoral thesis “Taxonomic studies in Dacrymycetes: Cerinomyces and allied taxa” for obtaining the degree of Doctor of Philosophy (in Botany and Mycology).

Supervisors:
Prof. Urmas Kõljalg, University of Tartu
Dr. Otto Miettinen, University of Helsinki (Finland)

Opponent:
Dr. Robert Lücking, Free University of Berlin (Germany)

Summary
Fungi represent one of the largest and diverse kingdoms of eukaryotes. Basidiomycota is the second most species-rich group within Fungi. Despite the ecological importance of Basidiomycota, i.e., its leading role in decomposition of wood in terrestrial ecosystems, its diversity and taxonomy are insufficiently known. Fulfilling the knowledge gap, the thesis presents taxonomic studies in dacrymycetes (Basidiomycota). Dacrymycetes occur only on dead wood and produce either of the two types of fruitbodies: gelatinous voluminous yellow or dry flat bleak-coloured. The latter type, also called corticioid fruitbodies, is the primary focus of the thesis. Traditionally, such corticioid fruitbodies in dacrymycetes were strictly associated with the family Cerinomycetaceae and its only genus Cerinomyces. This emphasis on a single character led to inclusion of dissimilar species into Cerinomyces, and over the time the genus became overly broad and polyphyletic. Thus, aim of the present thesis was to revise Cerinomyces and related taxa on a basis of DNA sequence-based phylogenetic analyses and morphological studies. As a result, Cerinomyces was reshaped to a more natural scope and became monophyletic. Priority for the corticioid morphology was abandoned, and gelatinous members were introduced to the genus. Instead of fruitbody type, the genus is now united by a set of microscopic characters: simple clamps, thin-walled aseptate basidiospores, and low amount of carotenoid pigments. Moreover, investigating taxa morphologically similar to Cerinomyces, the rest of dacrymycetes was partially revised. Special attention was paid to notable morphological structures called “dendrohyphidia” that are common in Cerinomyces, but were also found in other dacrymycetes. To accommodate such taxa in the Dacrymycetaceae family, a new genus Dendrodacrys was raised. In total, the thesis proposes 42 nomenclatural novelties to science, including one new genus, 27 new species, and 14 new combinations.