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

Figs 4 , 5

Etymology.

Carbo- (Latin) = carbonized, - stoma (Latin) = opening, referring to strongly carbonized opening of ascomata.

Diagnosis.

This new species is similar to Cryptococcomyces niger , but differs by the presence of a basal Covering stroma and ascospores covered by a thick gelatinous sheath.

Type.

CHINA, Yunnan Province, Lijiang, Laojunshan , 26.6418°N, 99.7673°E, alt. ca. 3495 m, on twigs of Juniperus squamata D. Don ( Cupressaceae ), 16 Aug. 2023, C. L. Hou, L. Zhuo, and S. Y. Zhao, HOU 2025 ( BJTC 2023155 , holotype) .

Sexual morph.

Ascomata on twigs, erumpent from bark, scattered, not associated with pale areas. In surface view, ascomata round or slightly irregular, 1000–2000 × 750–1000 µm, black (# 000000), opening by irregular splits to expose a yellow (# ffe 562) hymenium. Lips absent. In median vertical section, ascomata intracortical. Covering stroma 100–175 μm thick near the center of ascomata, 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 textura prismatica. Basal Covering stroma 25–35 µm thick, consisting of 3–7 μm diam., thick-walled, angular to globose cells. Internal matrix of Covering stroma 40–65 µm thick, consisting of hyaline, thin-walled, angular cells, filled with irregular crystals. Subhymenium 25–20 µm thick, consisting of hyaline textura porrecta. Paraphyses aseptate, filiform, not branched, curled or coiled at their tips, 130–145 × 1–1.5 µm, covered by a thin gelatinous sheath. Asci ripening sequentially, clavate, apex acute, 80–120 × 6–8 µm, thin-walled, J –, 8 - spored. Ascospores aseptate, filiform, tapering towards the apex, 30–40 × 1–1.5 μm, hyaline, covered by a ca. 2 µm thick gelatinous sheath.

Asexual morph.

Conidiomata and zone lines not seen.

Distribution.

Known only from Yunnan Province, China.

Notes.

The multi-locus gene analysis indicates that the sequences of Cry. carbostomaticus form a well-supported clade sister to the sequences of Cry. niger . Cryptococcomyces carbostomaticus is morphologically similar to Cry. niger , but the latter has a covering stroma without textura prismatica, no basal Covering stroma, and ascospores lack a thick gelatinous sheath. Therefore, Cry. carbostomaticus is considered to be a distinct species.

Figures

Figure 4. Cryptococcomyces carbostomaticus (HOU 2025 / BJTC 2023155, holotype) a ascomata on a twig of Juniperus squamata b, c mature ascomata. Scale bars: 2 mm (a); 1 mm (b, c).

Figure 5. Cryptococcomyces carbostomaticus on Juniperus squamata (HOU 2025 / BJTC 2023155, holotype) a part of an ascoma in vertical section, covering stroma with hyaline textura prismatica b paraphyses, mature asci with ascospores, and immature ascus. c Liberated ascospores. Scale bars: 100 μm (a); 10 μm (b, c).