Abstract
Chaetomidium, a genus in the Chaetomiaceae, comprises 12 species that produce similar cleistothecial ascomata with a membranous, mostly pilose, peridium. Approximately six species of this genus produce some type of modified peridium composed of cephalothecoid plates that previous authors have hypothesized to be a homologous character within the genus. To better understand the phylogenetic affiliations of Chaetomidium and distribution of the cephalothecoid peridium within this genus we performed phylogenetic analyses with LSU, β-tubulin and rpb2 sequence data. The results of these analyses showed that Chaetomidium is polyphyletic and should be restricted to its type, C. fimeti, and C. subfimeti. The remaining cephalothecoid and non-cephalothecoid species were scattered throughout the Chaetomiaceae and Lasiosphaeriaceae. The cephalothecoid species of Chaetomidium were distributed in three unrelated clades, suggesting that the morphological similarity among these particular species resulted from convergence instead of ancestry.
This study was financially supported in part by grants through the National Science Foundation to SMH (DEB-0118695) and ANM (DEB-0515558) and through an Illinois Natural History Survey Special Funding Grant to ANM. Cultures were generously provided by the Faculty of Medicine, Reus (FMR), Centraalbureau voor Schimmelcultures (CBS) and the Commonwealth Agricultural Bureaux International, Genetic Resource Collection (CABI). Sequences were generated in the Pritzker Laboratory for Molecular Systematics and Evolution at the Field Museum of Natural History.