Purpureomyces khaoyaiensis (Hywel-Jones) Luangsa-ard, Samson & Thanakitpipattana, comb. nov.

MycoBank number: MB 834906; Index Fungorum number: IF 834906; Facesoffungi number: FoF14496

Basionym: Cordyceps khaoyaiensis Hywel-Jones, Mycol. Res. 98: 939. 1994.

Synonyms: Metacordyceps khaoyaiensis (Hywel-Jones) Kepler et al., Mycologia 104: 185. 2012. Metarhizium khaoyaiense (Hywel-Jones) Kepler et al., Mycologia 106: 823. 2014.

Description and illustration: See Hywel-Jones (1994).

Cultural characteristics: Colonies on OA attaining a diam of 25 mm in 7 d, white, cottony, floccose, dense mycelium, reverse verona brown (223B). Hyphae septate, smooth-walled, hyaline, 1– 2 μm wide. Phialides lecanicillium-like, arising from aerial hyphae, cylindrical, tapering gradually towards the apex, hyaline, solitary or more often 2 or 4 in whorls on each node, (3 –)5.5 – 14(– 20) × 1– 2 μm. Conidia in long chains, hyaline, ovoid, 2– 3 × 1.5 – 2(– 3) μm.

Colonies on PDA attaining a diam of 15– 17 mm in 7 d, white to creamy, cottony, dense mycelium, reverse tawny olive (223D). Hyphae septate, smooth-walled, hyaline, 1 – 2 μm diam. Phialides lecanicillium-like, arising from aerial hyphae, cylindrical, tapering gradually towards the apex, hyaline, solitary or more often 2 or 4 in whorls on each node, (3–)6 – 13.5(– 18) × 1– 2 μm. Conidia in long chains, hyaline, ovoid, 2– 3(– 3.5) × (1 –) 1.5 – 2 μm.

Colonies on SDAY/4 attaining a diam of 16 – 20 mm in 7 d, white to creamy, cottony, dense mycelium. Colonies reverse robin rufous (340). Hyphae septate, smooth-walled, hyaline, 1– 2 μm diam. Phialides lecanicillium-like, arising from aerial hyphae, cylindrical, tapering gradually towards the apex, hyaline, solitary or more often 2 or 4 in whorls on each node, (7 –) 9.5 – 14.5(– 18) × (1 –)1.5– 2(– 3) μm. Conidia in long chains, hyaline, ovoid, 2– 3 × 1.5 – 2(– 3) μm.

Typus: Thailand, Nakhon Nayok Province, Khao Yai National Park, on Lepidoptera larva, in leaf litter, 14 Apr. 1997, N.L. Hywel-Jones (holotype NHJ 00885 preserved in metabolically inactive state, culture ex-type BCC 1376).

Habitat: Lepidoptera larva.

Known distribution: Thailand.

Additional materials examined: Thailand, Chiang Mai Province, Ban Hua Thung Community forest, 19.367814 N, 98.964903 E, on Lepidoptera larva, in leaf litter, 23 Sep. 2010, K. Tasanathai, P. Srikitikulchai & A. Khonsanit (BBH 30160, BCC 44287); idem., 5 Oct. 2012, K. Tasanathai, A. Khonsanit, W. Noisripoom, P. Srikitikulchai & R. Promharn (BBH 32908, BCC 55765), (BBH 32909, BCC 55766); idem., 29 Oct. 2012, K. Tasanathai, A. Khonsanit, W. Noisripoom, D. Thanakitpipattana, P. Srikitikulchai & S. Wongkanoun (BBH 40315, BCC 75721), (BBH 40208, BCC 75753), (BBH 40319, BCC 76485).

Notes: Purpureomyces khaoyaiensis is similar to P. pyriformis in having the same host and colour of the stroma. Both species occur on Lepidoptera larvae and produce purple stromata. They differ in the size and shape of perithecia, asci and ascospores. In culture, the asexual morph of P. khaoyaiensis and P. pyriformis is lecanicillium-like. Both P. khaoyaiensis and P. pyriformis produce white to cream mycelium on OA, PDA and SDAY/4, with similar sizes and shapes of the phialides and conidia.

Fig. 28. Purpureomyces khaoyaiensis (NHJ00855.01, BCC1376). A. Stroma arising from Lepidoptera larva. B. Oblique perithecial. C. Section through the stroma showing perithecia. D. Whole ascospore. E. Germination and microcyclic sporulation of the ascospores on slide. F. Colonies on OA. G–I. Phialides and conidia on OA. J. Colonies on PDA. K–M. Phialides and conidia on PDA. N. Colonies on SDAY/4. O–Q. Phialides and conidia on SDAY/4. Scale bars: A = 5 mm; B = 4 mm; C = 200 μm; D, E = 20 μm; G−I, K−M, O−Q = 10 μm.