Ophiocordyceps nigristroma Hong Yu bis, T. Sun, W. Q. Zou and Y. D. Dai, sp. nov.

Ophiocordyceps nigristroma Hong Yu bis, T. Sun, W. Q. Zou and Y. D. Dai sp. nov. Fig. 3 Etymology. The epithet ‘ nigristroma ’ refers to black stromata produced. Type. China, Xizang Autonomous Region, Changdu City, Zuogong County, the Dongda Mountains (29 ° 43 ' N, 98 ° 01 ' E, alt. 4963 m), isolated from Hepialidae larva, 2 June 2017, Hong Yu, (holotype: YHH 1705001; ex - type living culture: YFCC 17059245). Description. Teleomorph: Stromata grew from the head of the host Hepialidae larva buried in soil, sturdy, solitary, unbranched, woody, hard, dark brown, 8.4–13.6 cm long, 0.25–0.45 cm wide at the base and 0.1–0.2 cm wide at the top. The morphology of perithecia and asci was not observed, as the collections did not include any specimens that had reached sexual maturity. Anamorph: Hirsutella - type anamorph. Colonies on PDA slow-growing, attaining a diameter of 18–21 mm after 14 weeks at 20 ° C. Colonies dark brown to black, high mycelial density, texture hard, reverse dark brown. Hyphae hyaline, smooth-walled, 1.6–2.7 μm wide. Phialides from aerial mycelium straight to slightly flexuose, monophialidic, smooth, swollen base, lageniform, tapering into the apex forming a neck, 19.2–32.7 × 3.0–6.6 μm and 0.5–1.8 µm wide at the apex. Conidia one-celled, hyaline, smooth, fusiform or oval, 5.0–9.5 × 3.6–6.9 µm. Additional specimens examined. China, Xizang Autonomous Region, Changdu City, Zuogong County, the Dongda Mountains (29 ° 43 ' N, 98 ° 01 ' E, alt. 4963 m), isolated from the Hepialidae, 1 August 2014, Hong Yu (paratype YHH 1408001). Known distribution. At present known only from China. Notes. Ophiocordyceps nigristroma was closely phylogenetically related to O. karstii, O. liangshanensis, O. nujiangensis and O. sinensis. The formation of stromata on the head of the host was a characteristic common to all four species. However, the length of the stromata varies amongst the four species. Ophiocordyceps nigristroma had a stromata length slightly longer than O. sinensis, but shorter than O. karstii, O. liangshanensis and O. nujiangensis. O. nigristroma, on the other hand, had shorter phialides than O. liangshanensis and O. nujiangensis (Table 1). Thus, the morphological characteristics and molecular phylogenetic results supported that O. nigristroma was a new species in the genus Ophiocordyceps.