During a study of indoor fungi, 145 isolates belonging to Chaetomiaceae were cultured from air, swab and dust samples from 19 countries. Based on the phylogenetic analyses of DNA-directed RNA polymerase II second largest subunit (rpb2), β-tubulin (tub2), ITS and 28S large subunit (LSU) nrDNA sequences, together with morphological comparisons with related genera and species, 30 indoor taxa are recognised, of which 22 represent known species, seven are described as new, and one remains to be identified to species level. In our collection, 69 % of the indoor isolates with six species cluster with members of the Chaetomium globosum species complex, representing Chaetomium sensu stricto. The other indoor species fall into nine lineages that are separated from each other with several known chaetomiaceous genera occurring among them. No generic names are available for five of those lineages, and the following new genera are introduced here: Amesia with three indoor species, Arcopilus with one indoor species, Collariella with four indoor species, Dichotomopilus with seven indoor species and Ovatospora with two indoor species. The generic concept of Botryotrichum is expanded to include Emilmuelleria and the chaetomium-like species B. muromum (= Ch. murorum) in which two indoor species are included. The generic concept of Subramaniula is expanded to include several chaetomium-like taxa as well as one indoor species. Humicola is recognised as a distinct genus including two indoor taxa. According to this study, Ch. globosum is the most abundant Chaetomiaceae indoor species (74/145), followed by Ch. cochliodes (17/145), Ch. elatum (6/145) and B. piluliferum (5/145). The morphological diversity of indoor Chaetomiaceae as well as the morphological characteristics of the new genera are described and illustrated. This taxonomic study redefines the generic concept of Chaetomium and provides new insight into the phylogenetic relationships among different genera within Chaetomiaceae.
Keywords: Amesia X. Wei Wang, Samson & Crous; Amesia atrobrunnea (Ames) X. Wei Wang & Samson; Amesia cymbiformis (Lodha) X. Wei Wang & Samson; Amesia gelasinospora (Aue & Müller) X. Wei Wang & Samson; Amesia nigricolor (Ames) X. Wei Wang & Samson; Arcopilus X. Wei Wang, Samson & Crous; Arcopilus aureus (Chivers) X. Wei Wang & Samson; Arcopilus cupreus (Ames) X. Wei Wang & Samson; Arcopilus flavigenus (van Warmelo) X. Wei Wang & Samson; Arcopilus fusiformis (Chivers) X. Wei Wang & Samson; Arcopilus turgidopilosus (Ames) X. Wei Wang & Samson; Botryotrichum murorum (Corda) X. Wei Wang & Samson; Botryotrichum spirotrichum (R.K. Benjamin) X. Wei Wang & Samson; Chaetomiaceae; Chaetomium elatum Kunze; Chaetomium tectifimeti X. Wei Wang & Samson; Collariella X. Wei Wang, Samson & Crous; Collariella bostrychodes (Zopf) X. Wei Wang & Samson; Collariella carteri X. Wei Wang, Houbraken & Samson; Collariella causiiformis (Ames) X. Wei Wang & Samson; Collariella gracilis (Udagawa) X. Wei Wang & Samson; Collariella quadrangulata (Chivers) X. Wei Wang & Samson; Collariella robusta (Ames) X. Wei Wang & Samson; Collariella virescens (Arx) X. Wei Wang & Samson; Dichotomopilus X. Wei Wang, Samson & Crous; Dichotomopilus dolichotrichus (Ames) X. Wei Wang & Samson; Dichotomopilus erectus (Skolko & J.W. Groves) X. Wei Wang & Samson; Dichotomopilus funicola (Cooke) X. Wei Wang & Samson; Dichotomopilus fusus (Ames) X. Wei Wang & Samson; Dichotomopilus indicus (Corda) X. Wei Wang & Samson; Dichotomopilus pratensis (X.W. Wang & L. Cai) X. Wei Wang & Samson; Dichotomopilus pseudoerectus X. Wei Wang & Samson; Dichotomopilus pseudofunicola X. Wei Wang & Samson; Dichotomopilus ramosissimus (X.W. Wang & L. Cai) X. Wei Wang & Samson; Dichotomopilus reflexus (Skolko & J.W. Groves) X. Wei Wang & Samson; Dichotomopilus subfunicola (X.W. Wang & L. Cai) X. Wei Wang & Samson; Dichotomopilus variostiolatus (Carter) X. Wei Wang & Samson; Humicola olivacea X. Wei Wang & Samson; Indoor species; Melanocarpus tardus X. Wei Wang & Samson; Morphological diversity; Ovatospora X. Wei Wang, Samson & Crous; Ovatospora brasiliensis (Batista & Pontual) X. Wei Wang & Samson; Ovatospora medusarum (Meyer & Lanneau) X. Wei Wang & Samson; Ovatospora mollicella (Ames) X. Wei Wang & Samson; Ovatospora pseudomollicella X. Wei Wang & Samson; Ovatospora senegalensis (Ames) X. Wei Wang & Samson; Ovatospora unipora (Aue & Müller) X. Wei Wang & Samson; Phylogeny; Subramaniula anamorphosa (S.A. Ahmed et al.) X. Wei Wang & Samson; Subramaniula cristata (Ames) X. Wei Wang & Samson; Subramaniula cuniculorum (Fuckel) X. Wei Wang & Samson; Subramaniula flavipila X. Wei Wang & Samson; Subramaniula fusispora (G. Smith) X. Wei Wang & Samson.