Ophiocordyceps floriformis Tasanathai, Noisripoom & 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 floriformis Tasanathai, Noisripoom & Luangsa-ard sp. nov.

Fig. 2

Etymology.

The name refers to the fungus’s outer appearance on the host, which resembles a small flower.

Typus.

Thailand • Nakhon Ratchasima Province, Khao Yai National Park, Kong Kaeo Waterfall , on robber fly ( Asilidae , Clephydroneura sp. ) attached to the underside of a dicotyledonous leaf of forest plant, 3 October 2022, J. Luangsa-ard, K. Tasanathai, S. Mongkolsamrit, A. Khonsanit, W. Noisripoom, D. Thanakitpipattana, N. Kobmoo, MY 12948 (holotype BBH 51295 ) .

Description.

Sexual morph: Not observed. Asexual morph: Synnemata several, clavate, arising from the various parts of the head, thorax, and abdominal region of the host, cylindrical, unbranched, brown to dark brown at the base, light brown to grey towards the apex, 2–5 mm long, 50–100 μm wide, fertile region located at the terminal part of the synnemata. Conidiogenous cells Hymenostilbe - like, phialidic, forming a hymenial layer. Phialides cylindrical with short crowded denticles, (10 –) 12–17 (– 20) × 2–4 μm (n = 35, 14.2 ± 3.1 × 2.6 ± 0.6 μm). Conidia hyaline smooth-walled, fusoid, 6–10 × 2–3 μm (n = 35, 8.1 ± 1.3 × 2.5 ± 0.5 μm).

Culture characteristics.

All isolates of O. floriformis were successfully obtained. However, no growth was observed on PDA during the primary isolation process, possibly due to its fastidious nature.

Host.

Robber fly ( Asilidae , Clephydroneura sp. ).

Habitat.

The specimen was found on the underside of a dicotyledonous leaf of forest plants.

Additional materials examined.

Thailand • Nakhon Ratchasima Province, Khao Yai National Park, Mo Singto Nature Trail , on robber fly ( Asilidae , Clephydroneura sp. ) attached to the underside of a dicotyledonous leaf of a forest plant, 20 July 2014, K. Tasanathai, P. Srikitikulchai, S. Mongkolsamrit, T. Chohmee, R. Ridkaew, MY 4870 (paratype BBH 27634 ) .

Notes.

Ophiocordyceps floriformis exhibits a unique morphology by producing numerous short synnemata that emerge from the thorax and along the abdomen of its insect host. Ophiocordyceps floriformis produces subglobose fertile structures at the terminals, which have a white conidial powder, resembling that of O. buquetii , a species commonly found on ants. The phialides of O. floriformis are Hymenostilbe - like, whereas in O. buquetii , the phialides are cylindrical with papillate ends ( Mongkolsamrit et al. 2023). Based on the phylogenetic tree, O. floriformis belongs to the ' O. dipterigena ' complex, while O. buquetii is part of the ' O. australis ' complex. This species is fastidious, and no cultures could be obtained from the collected specimens. Hence, DNA was extracted from the synnemata of natural specimens.

Figures

Figure 2. Ophiocordyceps floriformis. A, B. Fungus on robber fly (Asilidae, Clephydroneura sp., Holotype BBH 51295); C. Synnemata; D. Head of synnema; E, F. Conidiogenous cells forming a hymenial layer; G. Conidia. Scale bars: 10 mm (A, B); 5 mm (C); 100 µm (D); 20 µm (E, F); 10 µm (G).