Neobelonopsis obtusa 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 obtusa Itagaki & Hosoya sp. nov.

Figs 9 , 13 , 14G

Etymology.

Named after rounded apices of ascospores.

Diagnosis.

Differs from N. acutata and N. multiguttata , which share 3-septate ascospores, by shorter ascospores with obtuse extremes and occurring only on woody substrates.

Holotype.

TNS-F-15602, Iryuda, Odawara City, Kanagawa Pref., 12 April 2007, on decaying wood of Aucuba japonica Thunb. var. japonica , ex-holotype culture NBRC 115381.

Description.

Apothecia superficial without subiculum and scuta, 0.2-0.3 mm high, with blackish brown (C80M80-100Y80-100K60) receptacle; disc 0.5-1.5 mm diam., white to pale gray when fresh, often turned grayish blue (C30-40M10Y10K30 or C40M20Y20K30) when moist, shrunk to 0.3-1 mm diam., pale yellow (Y20-30) or buff (M10Y30-40) when dried. Ectal excipulum 37-63 µm thick at base, 25-35 µm thick at the upper flank to margin; cortical cells hemispherical to short clavate, (10-)12-18 × (7-)8-12 µm at base, becoming slender and closely packed toward the upper flank to margin, containing refractive vacuoles at the protruding cells when mounted fresh in water. Medullary excipulum 60-75 µm thick, frequently dichotomously branched toward the margin. Asci (52-)56-78(-98) × 6-8.5(-10) µm, arising from croziers, with MLZ + apical pore. Ascospores (8-)13-17(-20) × 2.5-3.5 µm, subcylindrical with obtuse to subacute extremes, (1-)3-septate, containing small guttules. Paraphyses (40-)47-63(-70) × 2.5-3 µm, simple, (1-)2-3-septate, containing long refractive vacuoles at the apical cells when mounted fresh in water. Colony of NBRC 115381 on PDA entire, convex with abundant aerial hyphae, woolly to hairy, dark beige (M10Y20K30) from the surface, forming indistinct section and zonation observed clearer from the reverse, without soluble pigment and crystals; aerial mycelium abundant, membranous in the center, becoming densely fascicular, beige (C10-20M30Y30K10) to 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 to lageniform with determinate collarettes, up to 15 µm long, approximately 3 µm width at base, discrete to integrated, terminal or intercalary, pale brown, thick-walled, with cylindrical to wide funnel-shape collarettes of 4-6.5 × 2-3 µm; conidia aseptate, spherical to subspherical, abundantly aggregated in slimy heads, 2-2.5 µm diam., hyaline, thin-walled.

Additional specimens examined.

TNS-F-44017, Yoyogi, Shibuya Ward, Tokyo, 8 November 2011, on unidentified decaying wood, culture NBRC 115654; TNS-F-54934, Omama Town, Midori City, Gunma Pref., 21 April 2018, on unidentified decaying wood, culture NBRC 115656; TNS-F-86359, Mt. Yamizo, Daigo City, Kuji County, Ibaraki Pref., 24 May 2021, on decaying wood of Lindera sp., culture NBRC 115659; TNS-F-86638, Ikaho, Shibukawa Town, Gunma Pref., 5 October, 2021, on decaying wood of Quercus sp.; TNS-F-86658, Yugashima, Izu City, Shizuoka Pref., 15 October 2021, on decaying wood of Cornus controversa , culture NBRC 115664; TNS-F-86668, Kawazu City, Kamo County, Shizuoka Pref., 15 October 2021, on decaying wood of Morus australis .

Notes.

The ectal excipulum consisting of closely packed brownish cells of Neobelonopsis obtusa is similar to that of N. didymospora . However, the two species can be easily distinguished by the stable number of septa of ascospores (3-septate vs. 1-septate). Neobelonopsis obtusa forms an asexual stage on CMA (Figs 9N , 14G ) which closely resembles that of N. acutata in dendroid (irregularly branched) conidiophores (Figs 3N-O , 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 9. Neobelonopsis obtusa (TNS-F- 15602, holotype) A fresh apothecia on decaying unidentified wood B fresh apothecia during moist conditions C dried apothecia D vertical section of the apothecium (in LA) E refractive vacuoles in fresh marginal cells (in water) F vertical section at the basal apothecium (in LA) G ascospores (in CB / LA) H asci with ascospores (in CB / LA) I paraphyses (in CB / LA) J fresh paraphyses with long refractive vacuoles (in water) K blue-stained apical pore of ascus (in Melzer's solution after 3 % KOH pretreatment) L croziers at the base of asci (in CB / LA) M three months old colony on PDA N conidiophores with conidia (in water). Scale bars: 1 mm (A, C); 0.5 mm (B); 50 μm (D); 10 μm (E-L, N).

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.