Hypocreales » Ophiocordycipitaceae » Ophiocordyceps

Ophiocordyceps nutans

Ophiocordyceps nutans (Pat.) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora, Stud. Mycol. 57: 45 (2007)    

Index Fungorum number: IF 504313; Facesofungi number: FoF 13969

Parasitic on adult stinkbug. Sexual morph: Stroma 50 mm high, 2 mm wide, single, erected, simple, yellow, fibrous. Fertile head 18 mm long, 3 mm wide, bright yellow, fusiform, encompassed with a layer of palisade cells. Perithecia 310–540 × 130–350 (x̄ = 434 × 200, n = 15) μm, obliquely immersed, flask-shaped. Peridium 25–50 (x̄ = 34, n = 30) μm wide, 6-8 layered, comprising hyaline, thick-walled cells of textura angularis. Asci 100–190 × 2.5–4.5 (x̄ = 140 × 3.5, n = 15) μm, unitunicate, hyaline, narrow cylindrical, eight-spored, with a thickened cap. Apical cap 3–5.5 × 2–5 (x̄ = 4.4 × 3.5, n = 25) μm thick, hemispherical, pierced by a canal. Ascospore narrow filiform, as long as the asci in long, multiseptate, breaking into numerous secondary ascospores at maturity. Secondary ascospores 3–5 × 0.4–1.3 μm (x̄ = 4 × 0.8, n = 100), cylindrical, with truncated ends, hyaline, smooth, aseptate, straight.

Material examined – China, Guizhou Province, Guiyang City, Huaxi District, Tongxin Village, on stinkbug lying on ground, 23 June 2018, De-Ping Wei, TXC03 (HKAS 102461).

Notes – Four cryptic species including Ophiocordyceps asiana, O. tessaratomidarum,
O. nutans, O. neonutans have been recognized in Ophiocordyceps nutans complex (Khao-ngam et al. 2021). These species specifically infect stink bugs (Hemiptera) and are widely distributed (Friedrich et al. 2018, Khao-ngam et al. 2021). Species of this complex are characterized by producing dark brown to black stipe, pale yellow to orange yellow fertile head, obliquely-arranged immersed perithecia, narrow cylindrical asci and filiform multiseptate ascospores fragmenting into numerous cylindrical secondary ascospores at maturity (Friedrich et al. 2018, Khao-ngam et al. 2021). It is difficult to distinguish species in this complex solely based on macro-morphology due to their morphological variation. Our collection groups sister to O. nutans with maximum support. Herein we tentatively design it as O. nutans based on the phylogenetic analysis. The individual ITS-based phylogenetic analysis with sufficient taxa sampling is needed to confirm the natural taxonomic placement of our specimen.

 

 

Ophiocordyceps nutans (HKAS 102461). a Substrate. b Host. c Stroma emerging from host. d Apex of perithecia. e Fertile part. f Vertical section of fertile part. f, g Perithecia. h Ascus cap. i–k Part of asci. l Peridium. m palisade cell. n–q Secondary ascospores. Scale bars: d = 200 µm, e–g = 1000 µm, h–l = 30 µm, m = 50 µm, n–p = 5 µm (i–k, n–p mounted in cotton blue solution).

 

Reference:

Wei DP, Gentekaki E, Wanasinghe DN, Tang SM, Hyde KD. Diversity, molecular dating and ancestral characters state reconstruction of entomopathogenic fungi. Mycosphere. 13(2): 281–351.

 

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