A novel species and a new geographical record of Nigropunctata from Bambusa vulgaris in northern Thailand

Nigropunctata species are characterized by brown to dark brown, cylindrical, aseptate and guttulate ascospores, with a germ slit occasionally present. The ascospores are sometimes surrounded by a mucilaginous sheath. To date, no asexual morph of Nigropunctata species has been documented. Species in this genus are saprobes isolated from dead bamboo branches. Nigropunctata was initially introduced as an incertae sedis genus in Xylariales, but has recently been accommodated in Pallidoperidiaceae. Since Nigropunctata species share similar morphological characters and are cryptic, species identification based solely on morphology is insufficient. Therefore, we used a biphasic approach, incorporating morphology and multi-gene phylogenetic analyses of ITS, LSU, β-tub, rpb2 and tef-1α sequences to establish a new species, Nigropunctata chiangraiensis, and a new geographical record for N. khalidii. Our isolates match the morphological species concept of Nigropunctata in having dark brown and aseptate ascospores. However, the sheath of N. chiangraiensis is not constricted at the center, as seen in most Nigropunctata species.