Nais submersa H. Zhang & R. Yang, 2024

Yang, Rang, Gao, Yi-Bo, Zhang, Di, Zhang, Huang & Yu, Ze-Fen, 2024, Freshwater Sordariomycetes: a new species Nais submersa and a new record Natantispora unipolaris in Halosphaeriaceae from China, Phytotaxa 668 (3), pp. 252-262 : 257-258

Nais submersa H. Zhang & R. Yang , sp. nov. ( FIGURE 3 )

Index Fungorum number: IF902537, Facesoffungi number: FoF 16388

Etymology: Refers to the fungus was isolated from submerged wood.

Holotype: IFRD99002

Saprobic on decaying wood submerged in freshwater. Sexual morph: Ascomata 100–200 μm in diam., solitary, semi-immersed to erumpt, globose to subglobose, dark brown to black, coriaceous, ostiolate central, papillate. Peridium 10– 30 μm, composed of several layers of elongated cells. Paraphyses absent. Catenophyses present, persistent, numerous. Asci deliquescent, 56 × 28 μm and 72 × 29 μm (only two asci observed), 8-spored, unitunicate, saccate thin-walled throughout, no apical apparatus. Ascospores 18–24 × 7.5–11 μm (x = 20.4 × 9.3 μm, n=20), hyaline, ellipsoidal, 1- septate, slightly constricted at the septum, with a band of refringent globules around the equator and single large guttule in each cell, smooth-walled, thin-walled, several with unipolar apical appendage. Asexual morph: Undetermined.

Material examined: China, Yunnan Province, Jianshui City, Yangliu Dam, on submerged wood, 10 October 2023, W. Lin, HH3 ( IFRD 99002, holotype).

Notes: Nais submersa clusters in the clade which consists of Nais inornata (the type species of the genus), Natantispora unipolaris and Nat. retorquens . Its morphology fits well with the characters of Nais in having thin-walled asci which often deliquescing early, and ellipsoidal, 1-septate, hyaline ascospores, especially with a band of granular globose bodies around the ascospore equator. Because N. submersa has smaller asci and smaller ascospores than N. inornata and N. aquatica ( TABLE 2), we identify it as a new species in Nais .

Figures

FIGURE 3. Nais submersa (IFRD99002, holotype). a Ascoma on the substratum. b Vertical section of ascoma. c Peridium. d, e Asci. f Catenophyses. g–n Ascospores. Note the equatorial band (arrowed in h) and the unipolar apical appendages (arrowed in i). Scale bars: a = 100 µm, b = 50 µm, c–m = 10 µm.