Ophiocordyceps jilinensis Y.P. Xiao & Yu Yang, in Cao et al., Fungal Diversity 132: 489 (2025)

Index Fungorum number: IF 903017; MycoBank number: MB 903017; Facesoffungi number: FoF 16977; Figs. 1, 2

Etymology – refers to Jilin Province, the locality of the type specimen.

Holotype – HKAS 144583.

Parasitic on adult Orthoptera, which is found on the abaxial side of fern fronds, where a light brown mycelium envelops the entire host, without the presence of synnemata. Sexual morph: not observed. Asexual morph: Hirsutella-like. Hyphae hyaline and initially smooth, developing warts on older; septate, 3.2 µm to 4.8 µm in width. Phialides, mono- or polyphialidic, emerging from the hyphae laterally or at the ends, hyaline, cylindrical, adorned with small warts, are inflated at the base, with 2–3 arranged in a whorl, 19.2–35.7 × 3.2–4.5 µm (x̄ = 27.5 × 3.8 µm, n = 50), tapering to a slender, verruculose, with narrow neck 8.2–14.6 µm long, 1.5 µm wide. Conidia hyaline, smooth, ellipsoid or lemon shaped, arising from the apex of the neck singly, 5.3–7.8 × 4.2–5.3 µm (x̄ = 6.5 × 4.8 µm, n = 50), surrounded by mucous sheath.

Material examined – CHINA, Jilin Province, Baishan City, Fusong County, 42°25’N 127°27’E, 781 m asl, 10 Aug 2024, Yuan-Pin Xiao, Yu Yang, JL2421 (HKAS 144583, holotype); JL2420 (HKAS 144584, Paratype).

GenBank numbers – JL2421: PQ528946 (ITS), PQ528943 (LSU), PQ528940 (SSU), PQ522476 (rpb1), PQ569911 (rpb2), PQ522478 (tef1); JL2420: PQ528947 (ITS), PQ528944 (LSU), PQ528941 (SSU), PQ569912 (rpb2), PQ522479 (tef1).

Notes – Ophiocordyceps jilinensis clustered with Hirsu tella kirchneri and O. crinalis in the phylogenetic tree with support (100% MLBP, 1.00 PP) (Fig. 1). Comparing the ITS and tef1 sequences of O. jilinensis and H. kirchneri revealed 97.23% (13 bp differences), 96.91% (24 bp differences) sequence similarities, respectively. Comparing the LSU, tef1 and rpb1 sequences of O. jilinensis and O. crinalis revealed 97.27% (21 bp differences), 92.15% (51 bp differences) and 90.33% (61 bp differences), separately. Morphologically, O. jilinensis parasitizing the adult Orthoptera and have longer phialides (19.2–35.7 µm vs. 15–24 µm) and bigger conidia (5.3–7.8 × 4.2–5.3 µm vs. 4.5–6 × 2.5–3.5 µm) (Minter et al. 1983). Thus, we would like to introduce O. jilinensis as a new species based on phylogenetic and morphological analyses.

Figure 1 – A phylogram was constructed using Maximum Likelihood analysis with RAxML based on sequence data from six gene regions: LSU, ITS, SSU, tef1, rpb1 and rpb2 sequence data. Tolypocladium inflatum and T. ophioglossoides were employed as outgroup taxa. Nodes with Maximum Likelihood bootstrap values exceeding 75% and Bayesian posterior probabilities higher than 0.90 are indicated on the phylogram. Newly generated sequences are highlighted in bold red. “T” refers to a type specimen.

Figure 2 – Ophiocordyceps jilinensis (HKAS 144583, holotype). a Habitat. b Mycelium on host. c–e Phialides. f Phialides with conidia. g–i Conidia. Scale bars: c–f = 20 µm, g–i = 5 µm.