Neohelicosporium xishuangbannaensis Y. R. Xiong, Manawas., & K. D. Hyde 2024, sp. nov.

Neohelicosporium xishuangbannaensis Y. R. Xiong, Manawas., & K. D. Hyde sp. nov. Fig. 6 Etymology. Species epithet refers to the location name “ Xishuangbanna ” from where the holotype was collected. Holotype. MHZU 23-0156. Description. Saprobic on the rotting petiole of Elaeis guineensis. Sexual morph: Not observed. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substratum superficial, effuse, gregarious, brown. Mycelium composed of partly immersed, partly superficial, brown, septate, unbranched hyphae. Conidiophores 40–125 μm long, 3–6 μm wide (x = 68.4 × 4.4 μm, n = 20), macronematous, mononematous, flexuous, long, cylindrical, branched, septate, smooth-walled. Conidiogenous cells 7–14 μm long, 2.5–5.5 μm wide (x ̄ = 11.2 × 3.9 μm, n = 20), mono- to polyblastic, integrated, sympodial, terminal or intercalary, cylindrical, pale brown, smooth-walled; with denticles, 1.8–3.3 μm long, 1.1–2.3 μm wide (x ̄ = 2.4 × 1.4 μm, n = 20), arising from the juncture portion of two conidiogenous cells as tooth-like and papillate protrusions, mono- to polyblastic, pale brown or hyaline, smooth-walled. Conidia 16.5–20.5 μm diam. (x ̄ = 18.5 μm, n = 40) and conidial filament 1.8–3.2 μm wide (x ̄ = 2.4 μm, n = 40), 90–125 μm long (x ̄ = 107 μm, n = 40), solitary, acropleurogenous, helicoid, rounded at tip, coiled 2–3 ¼ times, 9–13 - septate, becoming loose in water, guttulate, slightly constricted at septa, hyaline to pale brown, smooth-walled. Culture characteristics. Conidia germinating on water agar and germ tubes produced from conidia within 12 h. Colonies growing on PDA attaining 2.5 cm diam. after six weeks at 25 ° C, irregular, undulate, umbonate, rough, superficial and partially immersed, brown aerial mycelium mixed with pale brown, deep brown at up and down junction area; reverse brown with deep brown. Material examined. China, Yunnan Province, Xishuangbanna City, an unidentified forest beside National Highway 219 (21 ° 93 ' N, 101 ° 24 ' E, 549.6 m elev.), rotting petiole of the Elaeis guineensis, 5 February 2023, Y. R. Xiong and Li Lu, XG 197 (MHZU 23-0156, holotype); ex-type, ZHKUCC 24-0119, other living culture ZHKUCC 24-0120. Notes. Two isolates obtained in this study developed an independent clade in the phylogenetic tree with 77 % ML, 79 % MP bootstrap support and 0.99 BIPP bootstrap support. The nucleotide differences excluding gaps between Neohelicosporium xishuangbannaensis and N. fusisporum (MFUCC 16-0642) are ITS: 2.81 % (15 / 533 base pairs), LSU: 1.06 % (9 / 852 base pairs), tef 1 - α: 2.41 % (22 / 912 base pairs) and rpb 2 sequence is unavailable. Neohelicosporium fusisporum was reported as a sexual and asexual morph by Jayasiri et al. (2017). Neohelicosporium xishuangbannaensis is different from the asexual morph of N. fusisporum (Jayasiri et al. 2017) in the size of conidia and conidiogenous cells (Table 3). In addition, the asexual morph of N. fusisporum (Jayasiri et al. 2017) has an intercalary conidiogenous cell, while N. xishuangbannaensis has an intercalary (Fig. 6 e, f) or terminal (Fig. 6 g, h) conidiogenous cell. Furthermore, the asexual morph of N. fusisporum (Jayasiri et al. 2017) has denticles with tooth-like or long neck cells, while N. xishuangbannaensis has a denticle with tooth-like and papillate protrusions. Based on these differences, herein we introduce N. xishuangbannaensis as a new species.