Phylogenetic relationships of Chaetomium and similar genera based on ribosomal DNA sequences

The 30 taxa sampled for this study were chosen based on their taxonomic position or particular morphological characters, which are related to those of Chaetomium. The 15 fungal isolates sequenced herein were obtained during a fungal biodiversity survey of tropical soils or from the collections of R.T. Hanlin. Fifteen species were selected from the published data. The. aligned sequences of the 5' portion of the 18S ribosomal DNA were analyzed to infer the phylogenetic relationships among Chaetomium and related genera. The sequence data confirmed the generic entity of Achaetomium and placed Ascotricha within the Xylariaceae. The analyses also defined the monophyletic lineage of the Microascaceae and the evolutionary linkages between the families Sordariaceae and Chaetomiaceae. The placement of Coniochaeta in the Coniochaetaceae and Chaetomium and Achaetomium in the Chaetomiaceae, under the order Sordariales, is supported by this study.