Abstract
A new species of Magnicamarosporium, M. diospyricola was found on dead or dying twigs of a dicotyledonous plant in southern Thailand. The new species is distinct from other species in Sulcatisporaceae, as it has dematiaceous dictyosporous conidia. It differs from Magnicamarosporium iriomotense in its smaller conidiomata and conidia. Bayesian inference and maximum likelihood analysis of combined LSU, SSU, ITS, and TEF1-alpha sequence data indicate that M. diospyricola is a well-resolved species, sister to M. iriomotense, in the family Sulcatisporaceae. The morphology and phylogenetic placement of the new species are discussed in this paper.