Ophiocordyceps sporangifera Y.P. Xiao, T.C. Wen & K.D. Hyde

Xiao, Yuan-Pin, Hongsanan, Sinang, Hyde, Kevin D., Brooks, Siraprapa, Xie, Ning, Long, Feng-Yao & Wen, Ting-Chi, 2019, Two new entomopathogenic species of Ophiocordyceps in Thailand, MycoKeys 47, pp. 53-74 : 53

Ophiocordyceps sporangifera Y.P. Xiao, T.C. Wen & K.D. Hyde sp. nov. Figs 3, 4

Etymology.

The specific epithet refers to the feature of the sporangium-bearing.

Sexual morph: Unknown. Asexual morph: Primary synnema 9-18 cm high 1-2 mm diam., arising from the head region of the larva, branching into 2-5, cylindrical, brown to deep brown, with small white fertile head on the top, not smooth. Fertile head 500-2000 µm long, 400-1000 µm diam., globose to subglobose, capitulum, white to brown, arising from the apical end of primary synnema, mess of sporangium on the surface. Sporangium 78-121 µm diam. (x̄ = 100 µm, n = 60), spherical, arising from the apical end of primary synnema, white colour when immature, becoming brown to dark brown after maturity, consisting of thick-walled cells. Secondary synnemata 1092-1937 × 21-34 µm, (x ‒= 1515 × 27 µm, n = 60), laterally from the primary synnema, brown to white, cylindrical, not smooth. Hyphae 1.8-2.8 µm wide (x̄ = 2.3 µm, n = 60), irregularly multi-septate, brown, cylindrical, smooth or rough, sometimes particularly expand. Phialides 25-40 × 1.3-2.5 µm (x̄ = 33 × 1.9 µm, n = 60), hirsutella-like, hyaline, solitary, unbranched, narrow slender, smooth. Conidia 6.7-9.8 × 2.5-3.8 µm (x̄ = 8.3 × 3.2 µm, n = 60), 1 cell, hyaline, subglobose to reniform, bound in mucilaginous spheres. Mucilaginous spheres 10.5-12.9 × 6.4-8.7 µm (x̄ = 11.7 × 7.5 µm, n = 60), composed of 1-12 conidia, hyaline, at phialide apex.

Culture Characteristics.

growing on PDA, reaching 2 cm diam., after 4 weeks at 25 °C,with circular, dense mycelium on the surface. After 6 weeks, the colour of the colony gradually deepened from white to dark brown from the periphery to the centre, with complex fold as 4 circle rings, reverse white to yellow in colour, with ring. Synnemata was produced after 8 weeks. Most of the characters are the same as the fresh collection except phialides and mucilaginous spheres. Phialides 56-86 µm long (x̄ = 71 µm, n = 60), 3-5 µm wide at base (x̄ = 4 µm, n = 60), 1.4-2.2 µm at top (x̄ = 1.8 µm, n = 60), hirsutella-like, hyaline, solitary, unbranched, narrow slender, smooth, 1-4 septa, not observed on host. Mucilaginous spheres 10.5-15.9 × 8.2-14.7 µm (x̄ = 12.7 × 11.5 µm, n = 60), 1-4 conidia, hyaline to brown. Observation stopped after 10 weeks.

Material examined.

THAILAND, Chiang Mai, The Mushroom Research Centre, on dead larva of Elateridae , Coleoptera , 6.5 cm long 0.38 cm diam., brown to dark brown, with thallus inside (larva), 18 July 2015, YuanPin Xiao, (MFLU 18-0658, holotype); THAILAND, Chiang Mai, The Mushroom Research Centre, on dead larva of Elateridae , Coleoptera , 5.8 cm long 0.4 cm diam., brown to dark brown, with thallus inside (larva), 22 August 2015, YuanPin Xiao, (MFLU 18-0659, paratypes, ex-type living culture, MFLUCC 18-0492); THAILAND, Chiang Mai, Samoeng on larva insect of Elateridae , Coleoptera , 5.5 cm long 0.32 cm diam., brown to dark brown, with thallus inside (larva), 18 June 2017, YuanPin Xiao, (MFLU 18-0660, paratypes, living culture, MFLUCC 18-0493, MFLUCC 18-0494).

Notes.

Ophiocordyceps sporangifera is closely related to O. myrmicarum D.R. Simmons & Groden in our phylogenetic tree (Fig. 1). The morphology of O. sporangifera is different from O. myrmicarum in having longer primary and secondary synnemata, a white to brown sporangium, shorter phialides and it infects insect larvae ( Lepidoptera , Cossidae ), while O. myrmicarum was found on an ant ( Myrmica rubra ) ( Simmons et al. 2015). The phylogenetic analysis does not have good support, but O. sporangifera is distinct from O. myrmicarum . In the phylogenetic tree, the relationships of O. sporangifera and O. myrmicarum are obscure because they share one clade with short branch length (100% ML/ 1 BYPP), while the two strains of O. sporangifera clustered together with a low bootstrap support (88% ML/ 0.90 BYPP). The type strain of O. sporangifera has 0 bp in nrSSU, 3 bp in TEF1α and 5 bp in RPB1 that are different from O. myrmicarum . However, the morphological features of those two species are different, thus, they should be treated as two separate species (Table 3).