Neobelonopsis bicolor 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 bicolor Itagaki & Hosoya sp. nov.

Figs 4 , 13 , 14B

Etymology.

Named after the two-color variability observed among the apothecia in a single population.

Diagnosis.

Characterized by apothecia that occur only on woody substrates, 2-celled ascospores, and monilioid hyphae surrounded by a gelatinous sheath that form on artificial media.

Holotype.

TNS-F-86605, Kagawa Town, Muroran City, Hokkaido, Japan, 3 August 2021, on decaying wood of Betula sp., ex-holotype culture NBRC 115569.

Description.

Apothecia superficial, without subiculum and scuta, 0.1-0.5 mm high, with blackish brown (C80M100Y80-100K60) to black receptacle; disc 0.8-1.5 mm diam., white to pale gray when fresh, shrunk to 0.5-1.2 mm diam., buff (M10Y30-40) or bluish gray (C30-40M20Y10-20K60) when dried. Ectal excipulum 40-50 µm thick at base, 25-40 µm thick at the upper flank to margin; cortical cells hemispherical to short clavate, 13-17 × 7.5-12 µm at base, becoming slender and smaller, moderately packed toward the margin. Medullary excipulum 10-25 µm thick, hyaline to pale brown. Asci (60-)67-80(-83) × 5-7.5 µm, arising from croziers, with MLZ + apical pore. Ascospores (10-)12-15(-17.5) × 2.5-3 µm, ellipsoid to fusiform with obtuse to subacute extremes, rarely constricted at the septum, (0-)1-septate, frequently containing two large guttules. Paraphyses (60-)62-77(-87.5) × 2.5-3(-4) µm, simple, rarely branched, 2-3-septate. Colony of NBRC 115569 on PDA convex, undulate, pulvinate, cottony to floccose, entirely pale gray (K10-40), darker from the reverse, without soluble pigment; crystals regular octahedron, 10-12.5 µm on a side, hyaline, forming on colony surface; aerial mycelium dense, white to pale gray.

Additional specimen examined.

TNS-F-86357, Mt. Yamizo, Daigo City, Kuji County, Ibaraki Pref., 24 May 2021, on decaying wood of Fraxinus sp., culture NBRC 115658; TNS-F-86606, Kagawa Town, Muroran City, Hokkaido, 3 August 2021, on decaying wood of Phellodendron amurense , culture NBRC 115663; TNS-F-86664, Yugashima, Izu City, Shizuoka Pref., 15 October 2021, on decaying wood of Zanthoxylum ailanthoides , culture NBRC 115665; TNS-F-86666, Mt. Amagi, Izu City, Shizuoka Pref., 15 October 2021, on decaying wood of Cornus controversa .

Notes.

Neobelonopsis bicolor shares biometry and morphology of ascospore with Belonopsis juncicola Graddon but differs in having larger asci (vs. 40 × 5 µm) and lignicolous habitat (vs. Juncus ) ( Graddon 1990).

Both TNS-F-86605 (holotype) and 86606, which were collected from the same location in Hokkaido on the same day in October, have bluish gray hymenium (Fig. 4C ) and pigmented medullary excipulum (Fig. 4F ). Other specimens collected from spring to summer (May to August) in Honshu (TNS-F-86357 and 86664) have whitish to yellowish hymenium (Fig. 4B ) and hyaline medullary excipulum (Fig. 4E ). In the phylogenetic tree (Figs 1 , 2 ), specimens with the two-color variability of hymenium formed a well-supported identical clade. Further sampling and morphological comparisons are needed to clarify whether these morphological differences depend on geographic or seasonal variability.

Neobelonopsis bicolor produces dark gelatinous hyphal structures on the colony surface of CMA and 2% MEA (Fig. 4M ). The hyphal structure is composed of monilioid cells hyaline to pale brown, 5-10 µm diam., containing abundant guttles and a thick-walls. The monilioid cells are arranged linearly or sympodially and branch vertically or laterally (Figs 4P , 14B ). The monilioid cells are covered with a thick gelatinous sheath (Fig. 4N ). No asexual stage observed in colonies on any medium.

Figures

Figure 1. Maximum likelihood tree inferred from ITS-LSU-RPB 1 concatenate sequences used in Tanney and Seifert (2020), together with sequences from additional taxa of Neobelonopsis and two new species of Trichobelonium. Significant branch supported by SH-aLRT (> 80 %) / Ultrafast BS (> 95 %) / BPP (> 0.95) are indicated. Type species are in red. Collection numbers are shown at the beginning of the species name (type strains are in boldface). The tree is rooted with Cadophora dextrinospora and C. fastigiata.

Figure 2. Maximum likelihood tree inferred from ITS sequences used in Tanney and Seifert (2020), together with sequences from additional taxa of Neobelonopsis, two new species of Trichobelonium, Mollisia obscura, and Cejpia hystrix. Significant branch supported by SH-aLRT (> 80 %) / Ultrafast BS (> 95 %) are indicated. Type species are in red. Collection numbers are shown at the beginning of the species name (type strains are in boldface). The tree is rooted with Cadophora dextrinospora and C. fastigiata.

Figure 4. Neobelonopsis bicolor (TNS-F- 86605, holotype) A fresh apothecia on decaying unidentified wood (TNS-F- 86666) B dried apothecia with yellowish disc and blackish flask (TNS-F- 86666) C dried apothecia with greyish discs D vertical section of the apothecium (TNS-F- 86666, in LA) E hyaline medullary excipulum (TNS-F- 86666, in LA) F brown medullary excipulum G ascospores (in CB / LA) H blue-stained apical pore of asci (in Melzer's solution after 3 % KOH pretreatment) I croziers at the base of asci (in CB / LA) J asci with ascospores (in CB / LA) K paraphyses (in CB / LA) L one month old colony on PDA M dark, gelatinous hyphal mass on CMA N monilioid hyphae surrounded by a gelatinous sheath (in diluted black ink) O octahedron crystals with monilioid hyphae on CMA (in water) P monilioid hyphae containing abundant guttles (in water). Scale bars: 1 mm (A, M); 0.5 mm (B, C); 50 μm (D-F); 25 μm (N, O); 10 μm (G-K, 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.