Mycoenterolobium aquadictyosporium sp. nov. (Pleosporomycetidae, Dothideomycetes) from a freshwater habitat in Thailand

Abstract

A study of freshwater fungi in Thailand led to the discovery of Mycoenterolobium aquadictyosporium sp. nov. Evidence for the novelty and placement in Mycoenterolobium is based on comparison of morphological data. The new species differs from the type species, M. platysporum, in having shorter and wider conidia, and from M. flabelliforme in having much longer and wider conidia. The hyphomycetous genus Mycoenterolobium is similar to Cancellidium but differs in the arrangement of conidial rows of cells at the attachment point to the conidiophores. The conidia of the former are made up of rows of cells, radiating in a linear pattern from a single cell attached to the conidiophore, while in Cancellidium, adherent rows of septate branches radiate from the conidiophore. Cancellidium conidia also contain branched chains of blastic monilioid cells arising from the conidia, while these are lacking in Mycoenterolobium. At maturity in Mycoenterolobium, the two conidial lobes unite and are closely appressed. Phylogenetic analyses based on a combined LSU, SSU, ITS, TEF1-α, and RPB2 loci sequence data support the placement of Mycoenterolobium aquadictyosporium close to the family Testudinaceae within Pleosporomycetidae, Dothideomycetes. The novel species Mycoenterolobium aquadictyosporium is described and illustrated and is compared with other morphologically similar taxa.