Geminoarcus maximus sp. nov. and Ceramothyrium brevis sp. nov., two novel aquatic hyphomycetes from Viet Nam

Geminoarcus maximus sp. nov and Ceramothyrium brevis sp. nov. were isolated from fallen leaves collected from Cuc Phuong, Ninh Binh and Phu Quoc National Park, Viet Nam, respectively. They were described and illustrated. Geminoarcus maximus was similar to the others three known species of Geminoarcus in shape and conidial development, but the sizes of the mature conidia were different from the other species. Ceramothyrium brevis ( Stanhughesia morph) has one main axis composed of several cells, 4–8 septate, sometimes have one (rarely two) lateral arm. This characteristic shows similarity with the Stanhughesia carniolica (morph of Ceramothyrium ). C. brevis differs from S. carniolica in the size of the conidia. The phylogeny based on D1/D2 of the 28S rDNA gene showed that Geminoarcus is nested in the Trichomeriaceae, Chaetothyriales, Eurotiomycetes. Ceramothyrium brevis is nested in Ceramothyrium spp. clade (Chaetothyriaceae, Chaetothyriales, Eurotiomycetes).