Phylogenetic relationships and distribution of Karstenella (Pezizomycetes)

Abstract

LANDVIK, S. 2008: Phylogenetic relationships and distribution of Karstenella (Pezizomycetes).-Karstenia 48: 13-19. Helsinki. ISSN 0453-3402. Phylogenetic analyses of partial SSU and LSU rDNA sequences confi rm that Karstenel-la vernalis is a member of the Pezizales. Substantiating this, we defi nitively report that the asci of Karstenella are operculate. Karstenella vernalis has been reported only from the type locality in Finland; we expand its known distribution to North America (New Mexico). The inconspicuous ascomata of Karstenella consist of very thin, resupinate apothecia borne on a subiculum. Hypotheses of a close relationship with Pyronema (Py-ronemataceae) or other highly reduced apothecial forms are rejected. Combined analyses show that Karstenella constitutes an independent lineage within a highly supported group of the lineages B (Morchellaceae-Discinaceae and Helvellaceae-Tuberaceae) and C (Ascodesmidaceae, Pyronemataceae, Sarcoscyphaceae and Sarcosomataceae), Calo-scyphaceae and Rhizinaceae. This corroborates recognition of a monotypic genus and family of Karstenella. A possible sister group relationship with Caloscyphaceae and/or Helvellaceae-Tuberaceae is suggested. The ascospores of Karstenella are shown to be bi-to multinucleate using DAPI staining. Excipulum structure and/or spore cytology support a shared origin with Caloscyphaceae and/or the Helvellaceae-Tuberaceae sub-lineage. Karstenella possesses the most reduced form of ascomata found so far outside lineages A (e.g. Ascobolaceae) and C (e.g. Ascodesmidaceae and Pyronemataceae).