Neotherrya circinata 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-

Neotherrya circinata Lan Zhuo & C. L. Hou sp. nov.

Figs 22 , 23

Etymology.

From circinatus (Latin) = to make round, referring to the curled tips of the paraphyses.

Diagnosis.

This new species is similar to Neotherrya catilliformis , but differs by its well-developed internal matrix of the Covering stroma, curled and coiled tips of paraphyses, and 8 - spored asci.

Type.

CHINA, Yunnan Province, Lijiang, Laojunshan , alt. ca. 3800 m, on twigs of Abies georgei ( Pinaceae ), 25 Jun. 2011, C. L. Hou, HOU 883 ( BJTC 2011041 , holotype) .

Sexual morph.

Ascomata on twigs, slightly erumpent from bark, scattered, not associated with pale areas. In surface view, ascomata round to irregular, 800–1000 µm in diam., black (# 000000), opening by irregular splits to expose a tangerine yellow (# ffb 700) hymenium. Lips absent. In median vertical section, covering stroma 65–85 μm thick near the center of ascomata, extending to the basal Covering stroma, consisting of an outer layer of carbonized, angular cells and an inner layer of hyaline, angular cells. Excipulum well-developed, formed by marginal paraphyses. Basal Covering stroma 25–35 µm thick, consisting of an outer layer of carbonized, angular cells and an inner layer of hyaline, angular cells. Internal matrix of Covering stroma well-developed, consisting of hyaline hyphae, filled with irregular crystals. Subhymenium 10–15 µm thick, consisting of textura intricata. Paraphyses aseptate, filiform, not branched, curled and coiled, slightly swollen at their tips, forming the black epithecium, 110–140 × 2–2.5 µm. Asci ripening sequentially, clavate, apex obtuse, 75–125 × 10–17 µm, thin-walled, J –, 8 - spored. Ascospores initially non-septate, with up to 7 septa when mature, cylindrical, acute at both ends, 23–38 × 2–4 μm, hyaline, covered by a 2–3 µm thick gelatinous sheath.

Asexual morph.

Conidiomata and zone lines not seen.

Additional specimens examined.

CHINA, Yunnan Province, Lijiang, Laojunshan , 26.6317°N, 99.7250°E, alt. ca. 3280 m, on twigs of Abies georgei ( Pinaceae ), 17 Jul. 2021, C. L. Hou, M. J. Guo, and Q. T. Wang, HOU 1587 ( BJTC 2020026 ) ; 26.6308°N, 99.7165°E, alt. ca. 4000 m, on twigs of A. georgei , 21 Jun. 2021, C. L. Hou, M. J. Guo, and H. Zhou, HOU 1824 ( BJTC 2021135 ) .

Distribution.

Known only from Yunnan Province, China.

Notes.

Phylogenetically, sequences of Neotherrya circinata form a well-supported clade (MLB = 100 %, MPB = 97 %, PP = 1.00) with N. catilliformis , but the latter lacks an internal matrix of the Covering stroma and has 4 - spored asci. Morphologically, the new species is similar to Neotherrya nematoidea , but N. nematoidea has well- developed periphysoids, and nematode-like ascospores.

Figures

Figure 22. Neotherrya circinata (HOU 883 / BJTC 2011041, holotype) a ascomata on a twig of Abies georgei b, c mature ascomata. Scale bars: 1 mm (a); 300 μm (b, c).

Figure 23. Neotherrya circinata on Abies georgei (HOU 883 / BJTC 2011041, holotype) a part of an ascoma in vertical section b paraphyses with curled and coiled tips, mature asci with ascospores, and immature ascus c liberated ascospores. Scale bars: 100 μm (a); 10 μm (b, c).