Abstract
Ophioceras is accommodated in the monotypic family Ophioceraceae (Magnaporthales, Sordariomycetes), and the genus is delimited based on molecular data. During an ongoing survey of bambusicolous fungi in southwest China, we collected a submerged decaying branch of bamboo from Sichuan Province, China and an Ophioceras species occurring on this substrate was observed and isolated. An Ophioceras taxon was delimited based on morphological characteristics and combined LSU, RPB1 and ITS sequence analyses and is described as Ophioceras sichuanense sp. nov. The species formed a well-supported clade basal to Ophioceras (100% ML, 1.00 PP). Based on the updated phylogenetic tree of Magnaporthales, Ceratosphaerella castillensis (generic type) and C. rhizomorpha formed a clade within Ophioceras and morphologically resemble Ophioceras. Therefore, Ceratosphaerella is synonymized under Ophioceras. The phylogenetic relationships of Ophioceras are discussed in relation to morphological similarities of genera in Magnaporthales. The generic circumscription of Ophioceras is emended.