Neobelonopsis acutata Itagaki & Hosoya, 2023

Itagaki, Hiyori & Hosoya, Tsuyoshi, 2023, A new genus Neobelonopsis and two new species of Trichobelonium (Helotiales, Ascomycota) discovered mainly from poaceous grasses native to Asia in Japan, MycoKeys 99, pp. 45-85 : 45

Neobelonopsis acutata Itagaki & Hosoya sp. nov.

Figs 3 , 13 , 14A

Etymology.

Named after the acute apices of ascospores.

Diagnosis.

Characterized by 3-septate ascospore with acute extremes and conidiophores densely aggregated in clusters. The present species resembles N. multiguttata . See Diagnosis in N. multiguttata for diagnostic characters.

Holotype.

TNS-F-86648, Yugashima, Izu City, Shizuoka Pref. Japan, 15 October 2021, on decaying culm of Miscanthus sinensis ; ex-holotype culture NBRC 115570.

Description.

Apothecia arising from scuta. Scuta superficial, scattered to gregarious, flat discoid, blackish brown (C80M100Y80-100K60), 0.1-0.3 mm diam., textura epidermoidea, composed of closely packed thick-walled cells. Apothecia 0.1-0.2 mm high, seated on subiculum, with grayish brown (C0-30M30Y40K60) to black receptacle; disc 0.25-1.4 mm diam., white to pale gray (K10) when fresh, shrunk to 0.2-1 mm diam., turns pale yellow (Y10) when dried. Ectal excipulum 25-40 µm thick at base, 15-20 µm thick at the upper flank to margin; cortical cells hemispherical to pyriform, 14-16 × 9-11 µm at base, becoming smaller to 10-12 × 7-9 µm toward the upper flank to margin, containing refractive vacuoles in the protruding cells when mounted fresh in water. Medullary excipulum 25-50 µm thick. Asci (50-)65-82(-85) × 5-9 µm, arising from croziers, with MLZ + apical pore. Ascospores 15-22(-27.5) × 2.5-3.5 µm, long fusiform, with acute apices, (1-)3(-4)-septate, containing abundant guttules, often 2-3(-4) large guttules and several smaller ones. Paraphyses (65-)70-85(-93) × 2.5-3 µm, simple, 2-3-septate, apical cells containing long refractive vacuoles when mounted fresh in water. Subiculum thinly covering the surface of substrates in patches, sparse to moderately abundant around the scuta and apothecia, shiny brown; subicular hyphae straight to curved, usually 3-5 µm diam., with 0.5-1 µm thick-walls, septate every 15-25 µm, perpendicularly branched, covered by gelatinous substance, forming bulbils of 30-45 µm across in the middle or tip, composed of densely aggregated globular or moniliform thick-walled cells, dark brown. Colony of NBRC 115570 on PDA moderately undulate, superficial, cottony to hairy, brownish gray (C20-40M40Y40K60) from the surface, zonation only observed from the reverse, without soluble pigment and crystals; aerial mycelium densely fascicular, white. Conidiophores aggregated in inconspicuous clusters on aerial hyphae, (semi-)macronematous, constricted, arising vertically or laterally from hyphae, pale to dark brown, smooth, thick-walled, frequently branched; phialides ampulliform with determinate collarettes, up to 15 µm long, approximately 4 µm width at base, discrete to integrated, terminal or intercalary, pale brown, thick-walled, with cylindrical to wide funnel-shape collarettes of 5-8 × 2.5-3 µm; conidia aseptate, spherical to subspherical, 2-2.5 µm diam., hyaline, thin-walled.

Additional specimen examined.

TNS-F-86671, Kawazu City, Kamo County, Shizuoka Pref., 16 October 2021, on decaying culm of M. sinensis , culture NBRC 115666.

Notes.

Neobelonopsis acutata resembles Belonopsis graminea (P. Karst.) Sacc. & P. Syd., which has a whitish disc that turns yellowish when dried, asci, ascospores and paraphyses with overlapped biometry ( Karsten 1871). However, N. acutata differs from B. graminea in its amyloid asci. Belonopsis graminea produces densely aggregated conidiophores (approximately 0.2 mm across, “spermogonium” sensu Karsten) and cylindrical to elongated fusiform conidia (8-10 × 1.5 µm, “spermatia” sensu Karsten) ( Karsten 1871), while N. acutata has sparsely aggregated conidiophores and spherical conidia (Figs 3M , 14A ).

Figures

Figure 3. Neobelonopsis acutata (TNS-F- 86648, holotype) A fresh apothecia on the decaying culm of Miscanthus sinensis B dried apothecia C stromata with sparse subiculum D one month old colony on PDA E vertical section of the apothecium (in LA) F refractive vacuoles in fresh marginal cells (in water) G asci with ascospores (in CB / LA) H paraphyses (in CB / LA) I paraphyses with a long refractive vacuole (in water) J blue-stained apical pore of ascus (in Melzer's solution after 3 % KOH pretreatment) K croziers at the base of ascus (in CB / LA) L ascospores (in CB / LA) M conidia (in water) N, O conidiophores (in water) P bulbile (in CB / LA) Q subicular hyphae (in CB / LA). Scale bars: 1 mm (A, B); 0.2 mm (C); 25 μm (E, Q); 10 μm (F-P).

Figure 13. Line-drawings of the Neobelonopsis and Trichobelonium species I vertical section of the apothecium showing the marginal structure of ectal excipulum, medullary excipulum, and hymenium II asci III paraphyses IV ascospores. Scale bars: 10 μm.

Figure 14. Asexual morph and hyphal structures of the Neobelonopsis and Trichobelonium species A conidiophores of N. acutata B monilioid hyphae of N. bicolor C conidiophores with conidia of N. cinnabarina D conidiophores with conidia of N. didymospora E conidiophores with conidia of N. microspora F conidiophores with conidia of N. multiguttata G conidiophores with conidia of N. obtusa H conidiophores with conidia of T. albobarbatum I hyphal mass with melanized appressorium-like structure of T. miscanthi. Scale bars: 10 μm.