Ophiocordyceps muscidarum Y. P. Xiao, K. D. Hyde & Y. Yang, 2025

Ophiocordyceps muscidarum Y. P. Xiao, K. D. Hyde & Y. Yang sp. nov.

Fig. 3 View Figure 3

Etymology.

The epithet “ muscidarum ” refers to its host belonging to the family Muscidae (Diptera).

Holotype.

China • Liaoning Province, Tieling City, Xifeng County, at 356 masl, 42.663°N, 124.482°E, parasitic on the fly ( Muscidae , Diptera ), collected on a tree stem, 20 July 2023, Yuanpin Xiao ( HKAS 132178 ) GoogleMaps .

Description

( HKAS 132178 ). Parasitic on flies ( Muscidae , Diptera ), collected on a tree stem. Host 6–8 mm long, 3–5 mm wide, without hyphae on the surface. Sexual morph: Stromata 5–7 mm long, 1–4 mm diam., one or several growing from the host prothorax, stipitate, capitate, unbranched, cinnamon to pale yellow. Stipe 3–5 mm long, 1–2 mm diam, cinnamon to pale brown, cylindrical, with a fertile apex. Fertile head hemispherical to globose, 1.5–4 mm, cinnamon to pale yellow, single. Perithecia 570–760 × 190–310 μm (x – = 665 × 250 µm, n = 30), immersed, ovoid to flask-shaped, thick-walled. Peridium 30–50 µm (x – = 40 µm, n = 60) wide, hyaline, three layers: outer layer to textura porrecta, middle layer textura prismatica, inner layer textura angularis. Asci 280–430 × 5.4–7.5 μm (x – = 355 × 6.5 µm, n = 60), 8 - spored, hyaline, cylindrical, with a thick apex. Apical cap 5.2–7.6 × 4.4–5.2 μm (x – = 6.4 × 4.8 µm, n = 60), thick, hyaline. Ascospores as long as asci, filiform, hyaline, easily breaking into part-spores. Secondary ascospores 7–10.5 × 1.6–2.5 μm (x – = 8.8 × 2.1 µm, n = 60) fusiform, 1 - celled, mostly straight, hyaline, smooth-walled. Asexual morph Not observed in natural substrates.

Additional material.

China • Liaoning Province, Tieling City, Xifeng County, at 374 masl, 42.665°N, 124.487°E, parasitic on the fly ( Muscidae , Diptera ), collected on a tree stem, 20 July 2023, Yuanpin Xiao TL 2378 ( HKAS 132275 , paratype) GoogleMaps .

Notes.

Phylogenetically, Ophiocordyceps muscidarum is closely related to O. globiceps , with support (100 % MLBP, 1.00 PP) (Fig. 1 View Figure 1 ). Base pair differences of LSU, ITS, and tef- 1 α sequences of O. globiceps are 4.14 % (34 / 820), 7.43 % (35 / 471), and 2.17 % (20 / 920), respectively. O. muscidarum is similar to O. globiceps in having a fly ( Muscidae , Diptera ) as the host, whereas O. muscidarum differs from O. globiceps in having larger perithecia and longer secondary ascospores ( Xiao et al. 2019; Table 3 View Table 3 ). Additionally, several Ophiocordyceps species exhibit a specific affinity for parasitizing dipteran flies. Notable examples include Ophiocordyceps dipterigena , O. globiceps , O. hemisphaerica , and O. lacrimoidis , all of which can be distinguished from O. muscidarum through phylogenetic analyses ( Berkeley and Broome 1873; Freire 2015; Hyde et al. 2016; Xiao et al. 2019). Another species, Ophiocordyceps discoideicapitata , has also been reported to infect flies but lacks molecular data ( Kobayasi and Shimizu 1982). Ophiocordyceps discoideicapitata differs from O. muscidarum in having smaller perithecia and shorter, cylindrical, truncated secondary ascospores ( Kobayasi and Shimizu 1982, Table 3 View Table 3 ). Based on morphology and phylogeny, Ophiocordyceps muscidarum is introduced as a new species in Ophiocordyceps .