Ophiocordyceps thilosuensis Mongkolsamrit, Liangsiri, Thanakitpipattana & Luangsa-ard, 2025

Mongkolsamrit, Suchada, Thanakitpipattana, Donnaya, Noisripoom, Wasana, Tasanathai, Kanoksri, Liangsiri, Kanraya, Jaiyen, Somruetai, Rungjindamai, Nattawut, Stadler, Marc & Luangsa-ard, Jennifer, 2025, Multi-locus molecular phylogenetic analysis reveals four new species and a new record of Ophiocordyceps (Ophiocordycipitaceae, Hypocreales) on dipteran hosts in Thailand, MycoKeys 119, pp. 235-261 : 235-261

Ophiocordyceps thilosuensis Mongkolsamrit, Liangsiri, Thanakitpipattana & Luangsa-ard sp. nov.

Fig. 6

Etymology.

Refers to the locality where the type specimen was found, Thi Lo Su Waterfall.

Typus.

Thailand • Tak Province, Umphang Wildlife Sanctuary, Thi Lo Su Waterfall , on fruit fly ( Tephritidae , Anastrepha obliqua ) attached to the underside of a bamboo leaf of a forest plant, 25 November 2010, K. Tasanathai, P. Srikitikulchai, A. Khonsanit, W. Noisripoom, K. Sansatchanon, MY 6446.01 (holotype BBH 30265 , ex-type culture BCC 46607 ) .

Description.

The dead fly hosts were covered with sparse, yellowish-white hyphae. Stromata stipitate, two stromata arising from the thorax region of host, beneath the wings, capitate, unbranched. Stipes cylindrical, smooth, yellowish white ( NN 155 A), 4–8 mm long, 0.5–1.5 mm wide. Sexual morph: Fertile heads disc-shaped, upper surface slightly convex, yellowish white, located at the tip of the stipes, 1–2 mm thick, 1–2.5 mm diam. Perithecia immersed, ovoid to obclavate, (700 –) 920–1065 (– 1075) × (240 –) 300–350 (– 400) μm (n = 30, 990.6 ± 72.3 × 325 ± 25.2 μm). Asci cylindrical, (320 –) 411–754 (– 880) × 5–7 μm (n = 30, 582.8 ± 171.4 × 6 ± 1 μm), with cap 3–6 μm thick. Ascospores filiform, multi-septate, breaking into 64 part-spores, cylindrical to fusoid, (6 –) 7.5–12 × (1 –) 1.5–2 μm (n = 50, 9.8 ± 2.1 × 1.6 ± 0.3 μm). Asexual morph: Synnemata arising from posterior abdomen region of host, solitary or multiple, cylindrical, unbranched, yellowish white, 3–10 × 0.5–1 mm, fertile part located at the two-thirds length of the synnemata. Conidiogenous cells Hymenostilbe - like, phialidic, forming a hymenial layer. Phialides cylindrical with short crowded denticles, (10 –) 12–18 (– 20) × (2 –) 2.5–3.5 (– 4) μm (n = 30, 14.7 ± 3 × 3.1 ± 0.5 μm). Conidia hyaline smooth-walled, obovoid, (5 –) 5.5–7.5 (– 8) × 2–3 μm (n = 30, 6.5 ± 0.9 × 2.5 ± 0.5 μm).

Culture characteristics.

Colonies on OA attaining a diam. of 7–10 mm in 30 days, mycelium sparse, white, reverse pale yellow (165 D). Conidia and reproductive structures not observed. Colonies on PDA attaining a diam. of 7–10 mm in 30 days, high mycelium density, white, reverse pale yellow (165 D). Conidia and reproductive structures not observed.

Host.

Fruit fly ( Tephritidae , Anastrepha obliqua ), soldier fly ( Stratiomyidae , Sarginae ).

Habitat.

Specimen was found on the underside of a bamboo leaf of a forest plant.

Additional materials examined.

Thailand • Tak Province, Umphang Wildlife Sanctuary, Thi Lo Su Waterfall , on fruit fly ( Tephritidae , Anastrepha obliqua ) attached to the underside of a bamboo leaf, 25 November 2010, K. Tasanathai, P. Srikitikulchai, A. Khonsanit, W. Noisripoom, K. Sansatchanon, MY 6439 (paratype BBH 30099 , ex-paratype culture BCC 47494 ), and MY 6446.02 ( BBH 30265 , culture BCC 46608 ); MY 6441 ( BBH 30100 , culture BCC 46606 ) .

Notes.

Ophiocordyceps thilosuensis has been collected from a bamboo forest. This species exhibits unique morphological characteristics. The fly hosts are covered with sparse hyphae that are yellowish-white in colour. The stromata range from yellowish white. The fertile parts are disc-shaped and located at the terminal of the stipe. These characteristics, which resemble those of Hevansia novoguineensis , occur on spiders and can be found on the underside of dicotyledonous leaves in the forest ( Mongkolsamrit et al. 2022).

Figures

Figure 6. Ophiocordyceps thilosuensis. A, B. Fungus on a fruit fly (Tephritidae, Anastrepha obliqua, Holotype BBH 30265); C. Perithecia; D. Ascus; E. Ascus cap; F. Part-spores; G, H. Conidiogenous cells forming a hymenial layer; I. Conidia; J, K. Colonies on OA at 30 days (J obverse, K reverse); L, M. Colonies on PDA at 30 days (L obverse, M reverse). Scale bars: 3 mm (A); 4 mm (B); 500 µm (C); 80 µm (D); 10 µm (E, F, G – I); 10 mm (J – M).