Cryptococcomyces niger Lan Zhuo & C. L. Hou, 2025

Zhuo, Lan, Wang, Hai-Qi, Zhang, Peng, Sui, Xiao-Nan, Guo, Mei-Jun, Wang, Shi-Juan & Hou, Cheng-Lin, 2025, New genera and species of coniferous twig-inhabiting Rhytismatales from China, IMA Fungus 16, pp. e 138790-e 138790 : e138790-

Cryptococcomyces niger Lan Zhuo & C. L. Hou sp. nov.

Figs 8 , 9

Etymology.

Niger (Latin) = black, referring to the black ascomata.

Diagnosis.

This new species is similar to Cryptococcomyces crystallinus , but differs by having an internal matrix of the Covering stroma without crystals.

Type.

CHINA, Yunnan Province, Lijiang, Laojunshan , 26.6322°N, 99.7250°E, alt. ca. 3880 m, on twigs of Juniperus squamata ( Cupressaceae ), 23 Jun. 2020, C. L. Hou, M. J. Guo, and Q. T. Wang, HOU 1625 ( BJTC 2020067 , holotype) .

Sexual morph.

Ascomata on twigs, scattered, not associated with pale areas. In surface view, ascomata elliptical to round, 800–1000 × 900–1200 µm, black (# 000000), erumpent from bark, opening by radial splits to expose a pale yellow (# ffff 9 d) to yellow (# ffd 400) hymenium. Lips absent. In median vertical section, ascomata intracortical. Covering stroma 110–125 μm thick near the center of the ascomata, not extending to the basal Covering stroma, consisting of an outer layer of remains of the host cortex, an inner layer of carbonized, angular to globose cells, and an innermost layer of hyaline angular cells embedded in the hyaline gelatinous matrix. Basal Covering stroma absent. Internal matrix of Covering stroma 90–110 µm thick, consisting of hyaline, thin-walled short hyphae in a gelatinous matrix. Subhymenium 20–30 µm thick, consisting of hyaline textura porrecta. Paraphyses aseptate, filiform, not branched, curled or coiled at tips, 125–150 × 1–2 µm, covered by a thin gelatinous sheath. Asci ripening sequentially, clavate, apex obtuse to acute, 72–95 × 6–8 µm, stalked, thin-walled, J –, 8 - spored. Ascospores aseptate, filiform, tapering towards the apex, 30–40 × 1 μm, hyaline.

Asexual morph.

Conidiomata and zone lines not seen.

Additional specimens examined.

CHINA, Yunnan Province, Lijiang, Laojunshan , 26.6322°N, 99.7250°E, alt. ca. 3880 m, on twigs of Juniperus squamata ( Cupressaceae ), 26 Jul. 2024, C. L. Hou, L. Zhuo, and X. N. Sui, HOU 2303 ( BJTC 2024153 ) .

Distribution.

Known only from Yunnan Province, China.

Notes.

The multi-locus gene analysis indicates that the molecular sequences of Cry. niger form a well-supported clade sister to Cryptococcomyces carbostomaticus . Cry. carbostomaticus is distinguished by presence of a basal Covering stroma and textura prismatica on innermost layer of the covering stroma. Morphologically, Cry. niger is similar to Coccomyces petersii , and both of these two species occur on Juniperus spp. However, the covering stroma of Co. petersii is composed entirely of carbonized globose cells, whereas that of Cry. niger includes an innermost layer of hyaline angular cells embedded in a hyaline gelatinous matrix. Additionally, Co. petersii has larger asci (85–110 × 8–10 µm). The basal Covering stroma of Co. petersii is reduced to a subiculum of dark brown hyphae, while Cry. niger lacks a basal Covering stroma but possesses a well-developed internal matrix within the Covering stroma, consisting of hyaline hyphae.

Figures

Figure 8. Cryptococcomyces niger (HOU 1625 / BJTC 2020067, holotype) a ascomata on a twig of Juniperus squamata b, c mature ascomata. Scale bars: 2 mm (a); 500 μm (b, c).

Figure 9. Cryptococcomyces niger on Juniperus squamata (HOU 1625 / BJTC 2020067, holotype) a part of an ascoma in vertical section, innermost layer of covering stroma with hyaline angular cells embedded in the hyaline gelatinous matrix b paraphyses, mature asci with ascospores, and immature ascus c liberated ascospores. Scale bars: 100 μm (a); 10 μm (b, c).