Ophiocordyceps spicatus L.S. Zha & P. Chomnunti, 2021

Zha, Ling-Sheng, Kryukov, Vadim Yu, Ding, Jian-Hua, Jeewon, Rajesh & Chomnunti, Putarak, 2021, Novel taxa and species diversity of Cordyceps sensu lato (Hypocreales, Ascomycota) developing on wireworms (Elateroidea and Tenebrionoidea, Coleoptera), MycoKeys 78, pp. 79-117 : 79

Ophiocordyceps spicatus L.S. Zha & P. Chomnunti sp. nov. Fig. 3

Etymology.

Referring to the spicate fertile head.

Sexual morph.

Parasitising a Tenebrionoidea larva ( Coleoptera ) living in humid and decayed wood. The larva is cylindrical, 7.5 mm long and 1.0-1.1 mm thick, yellowish-brown. White mycelia stuff the body cavity, also partially cover the intersegmental membranes of the body surface. Stroma arising from the first quarter of the larval body, single, fleshy, 5 mm in length. Stipe yellow, cylindrical, 3.5 mm long and 0.35-0.4 mm thick, surface rough and pubescent. Fertile head spicate, unbranched, orange, 1.5 mm long and 0.5-0.7 mm thick, obviously differentiated from stipe; its surface rugged and consisting of many humps (outer portions of perithecia), tops of the humps obtuse and with opening ostioles, darker in colour. Perithecia partially immersed and obliquely or at right angles to the surface of stipe, broadly pyriform, 200-250 × 170-200 μm; walls 25-35 μm thick. Asci cylindrical, 5-9 μm thick, middle part wider than two terminal parts; caps hemispheric, 4.6-5.3 (x - = 4.9, n = 30) μm wide and 4.0-4.6 (x - = 4.3, n = 30) μm high. Ascospores filiform; part-spores cylindrical, truncated at both ends, 3.5-6.5 (x - = 4.7, n = 30) μm long and 1.7-2.0 μm thick. Asexual morph. Unknown.

Material examined.

China, Guizhou Province, Leishan County, Leigongshan Mountain , 26°22'18"N, 108°11'28"E, 1430 m alt., 2 August 2016, Ling-Sheng Zha (MFLU 18-0164, holotype) .

Known distribution.

China (Guizhou).

Host.

Growing on a Tenebrionoidea larva ( Coleoptera ) living in humid and decayed wood in a broad-leaved forest.

Notes.

Ophiocordyceps spicatus is morphologically somewhat similar to O. formosana ( Kobayasi and Shimizu 1981; Li et al. 2016), but it has a much smaller stroma (stipes 6-10 (or 19-37) mm long and 1.5-1.7 (or 2-4) mm wide in O. formosana ), a spicate and rugged fertile head (surface entire and flattened, never spicate or rugged in O. formosana ) and partially immersed perithecia (immersed in O. formosana ).

Nucleotide sequences of O. spicatus are most similar to those of O. formosana , but there is 5.2% bp difference in ITS, 2.0% bp difference in TEF1-α and 0.1% bp difference in SSU (LSU rDNA sequence unavailable for O. formosana ). LSU of O. spicatus is> 5.6% bp different to all LSU available in GeneBank. Additionally, on the phylogenetic tree, O. spicatus is closely related (100% ML/100% MP/1.00 PP) to O. formosana , but they form into two distinct branches which also support them being two separate species (Fig. 1 ).

Figures

Figure 1. Maximum Likelihood (ML) tree of Ophiocordyceps borealis sp. nov., O. spicatus sp. nov. and their allies inferred from a combined SSU, LSU and TEF 1 - α gene dataset. Bootstrap support values of ML and Maximum Parsimony (MP)> 60 % and posterior probabilities (PP) of Bayesian Inference> 0.9, are indicated above the nodes and separated by ' / ' (ML / MP / PP).

Figure 3. Ophiocordyceps spicatus (MFLU 18 - 0164) a infected larva in decayed wood b habitat environment c fertile head of stroma d transverse section of fertile head, on which sparse arranged perithecia are shown e Asci f Ascospores and part-spores. Scale bars: 200 µm (c); 100 µm (d) 10 µm (e, f).