Chaetothyriales

Chaetothyriales is an order of fungi within the class Eurotiomycetes of the phylum Ascomycota. Members are predominantly dematiaceous, meaning pigmented by melanin, and include yeast-like forms as well as filamentous, slow-growing fungi. The order comprises several families, notably Herpotrichiellaceae and Chaetothyriaceae.

Ecology and distribution: Many Chaetothyriales are rock-inhabiting or black yeasts adapted to stressed habitats, such as bare rocks, tree bark, and desert soils. They are also found in indoor environments and on human skin as part of the microbiota in some cases. Their tolerance to desiccation, salinity, and UV radiation is notable.

Pathogenicity: Some species are opportunistic pathogens in humans and animals. They can cause a range of infections, from phaeohyphomycoses to tinea nigra. Notable members include Exophiala dermatitidis, a frequent cause of systemic or subcutaneous infections, and Hortaea werneckii, the etiologic agent of tinea nigra.

Morphology and taxonomy: Chaetothyriales fungi are typically melanized and may exist as yeast-like forms or hyphae. Molecular phylogenetics have clarified their relationships within Eurotiomycetes, contributing to taxonomic updates in recent decades. The order is defined by a combination of genetic characteristics and morphological traits, reflecting diversity across ecological niches.