<br> During a survey of microflora associated with dead plant substrates in coastal regions of Guangdong Province, China, we identified several interesting Dothideomycetes fungi and provided refined updated phylogenetic analyses for<br> Dictyosporium<br> and<br> Melomastia<br> species. Two novel species are introduced,<br> Dictyosporium thecatum<br> and<br> Melomastia shenzhenensis<br> , based on molecular and morphological evidence. New host records of<br> M. beihaiensis<br> ,<br> M. hydei<br> and<br> M. fusispora<br> are also reported in this paper. Molecular phylogenetic studies of new isolates were based on concatenated (i) ITS, LSU,<br> tef<br> 1-α and (ii) LSU, SSU, ITS,<br> tef<br> 1-α gene regions for<br> Dictyosporium<br> and<br> Melomastia<br> , respectively. These taxonomic novelties were recognised by comparing morphological characteristics with closely-related taxa.<br> Melomastia shenzhenensis<br> closely clustered with<br> M. oleae<br> (CGMCC 3.20619 and UESTCC 21.0003) with high statistical support value (ML/BYPP = 100%/1.00). Morphologically,<br> Melomastia shenzhenensis<br> can be distinguished from<br> M. oleae<br> in having larger of ascomata, ostiolar canal and peridium and smaller asci and ascospores.<br> Dictyosporium thecatum<br> forms a distinct basal clade with<br> D. sexualis<br> (MFLUCC 10-0127).<br> Dictyosporium thecatum<br> is different from<br> D. sexualis<br> in having smaller ascomata, asci and ascospores and possesses a larger mucilaginous sheath surrounding ascospores than<br> D. sexualis<br> . Two pairwise identity analyses were conducted for<br> Dictyosporium<br> and<br> Melomastia<br> . The resulting sequence identity scores were saved as a matrix and visualised as plots with a colour key to indicate the correspondence between pairwise identities. This study offers new insights into saprobic Dothideomycetes colonising dead woody substrates in coastal habitats of Guangdong Province, China.<br>
