Mariannaea macrochlamydospora, a new hyphomycete (Nectriaceae) from soil in the Bonin Islands, Japan

• Morphology of Mariannaea macrochlamydospora resembles those of M. elegans, M. aquaticola and M. samuelsii.
• This species is characterized by large chlamydospores.
• Mariannaea superimposita related to Mariannaea in Nectriaceae on ITS-D1/D2 phylogeny.

Mariannaea macrochlamydospora, a new hyphomycete classified in the Nectriaceae (Ascomycota), was isolated from a soil sample collected in the Bonin Islands, Japan. It is characterized by a yellow to brownish colony, verticillate conidiophores and imbricate chains of fusiform conidia. Morphologically, the species is similar to M. elegans, M. aquaticola and M. samuelsii, but differs from them in phylogeny and with respect to conidia or phialides morphology. Chlamydospores of this species are also larger than those of all other species of Mariannaea.