Proliferodiscus ailaoensis L. Luo & K.D. Hyde, 2025

Luo, Le, Chethana, K. W. Thilini, Zhao, Qi, Thiyagaraja, Vinodhini & Al-Otibi, Fatimah, 2025, Unveiling fungal diversity: a novel species of Proliferodiscus (Lachnaceae, Helotiales) discovered in China, Phytotaxa 682 (3), pp. 227-239 : 232-233

Proliferodiscus ailaoensis L. Luo & K.D. Hyde , sp. nov. ( Fig. 2 )

Index Fungorum number: IF 902902; Faces of fungi number: FoF 16788

Etymology:— the epithet refers to the collection site of the type specimen.

Holotype:— HKAS 137596

Saprobic on dead twigs. Sexual morph: Apothecia discoid, 0.7–2.2 mm diameter when dry, scattered to gregarious, sessile, superficial, yellow when fresh and yellow to cream white when dry. Receptacle surface yellow to white and cupulate with bushy hairs. Discs flat and circular, slightly sunken, yellow when fresh, brown when dry. Hairs 3.5–5.3 µm wide, cylindric, hyaline, deeply brown on receptacle, septate, thin-walled, slightly rough. Hymenium 57–184 µm, brown, with asci and paraphyses immersed in the gelatinized substances. Ectal excipulum 33–68 µm thick, comprised of thin-walled, hyaline cells of textura globulosa to textura porrecta, non-gelatinous. Medullary excipulum 20–53 µm (x = 34 µm, n = 30), composed of thin-walled, hyaline to yellowish, gelatinized cells of textura intricata. Paraphyses 0.9–2.5 µm wide (x = 1.5 µm, n = 30), filiform, cylindrical, rounded apex, aseptate, unbranched. Asci 64–104 × 8.3–15.3 µm (x = 85 × 12 µm, n = 50), eight-spored, cylindrical to clavate, J- in Melzer’s reagent, tapered to long stipitate base. Ascospore s 27–52 × 1.2–3 µm (x = 39.6 × 2.1 µm, n = 60), overlapping fascicles, narrowly fusoid with acute ends, sinuous, 4–6-septate, smooth. Asexual morph: undetermined.

Material examined: — CHINA. Yunnan: Ailao Mountain , on a dead twig of an unidentified tree, alt. 2451 m, 25 August 2022, Le Luo, ly560 ( HKAS 137596 , holotype) ; ibid., ly582 ( HKAS 137591 ) .

Notes: —Our specimens HKAS 137596 and HKAS 137591 grouped in a distinct clade, separated from the clade comprising Proliferodiscus longisporus and P. tricolor with 99% MLBS and 0.99 BIPP support ( Fig. 1 ). The new species, P. ailaoensis , morphologically differs from P. longisporus by having yellow to cream white apothecia, a yellow to white-haired receptacle surface, yellow or brown discs, aseptate and unbranched paraphyses, 4–6-septate ascospores, while the latter is characterized by orange or brownish-orange apothecia, a reddish-white to reddish-grey haired receptacle surface, orange or brown discs, septate paraphyses branched at the base, and 0–3-septate ascospores ( Li et al. 2022). Our species also differs from P. tricolor by having different colored hairs, aseptate paraphyses, and longer ascospores (27–52 µm vs. 10–14 µm) while P. tricolor has bluish-grey or pale violet-grey hairs and sparse septate paraphyses ( Popov 2013). Proliferodiscus ailaoensis differs from P. caeruleoniger , which lacks molecular data, in terms of hair colour (yellow to white vs. deep blue-black) ( Spooner 1987). Therefore, P. ailaoensis is introduced as a novel species that can be distinguished from P. longisporus and P. tricolor , not only through phylogenetic analysis, but also by its distinct morphological characteristics.

Figures

FIGURE 1. Phylogram of RAxML analysis based on the combined LSU and ITS sequence dataset. Bootstrap support values for maximum likelihood equal to or greater than 50%, and Bayesian posterior probability equal to or greater than 0.95 BYPP are indicated at the nodes as ML/BYPP. The generic names are denoted on the right side of the phylogenetic tree. Type strains are in bold. The newly generated isolates are in red.

FIGURE 2. Proliferodiscus ailaoensis (HKAS 137596, holotype). a. Fresh apothecia growing on dead wood. b–c. Dry apothecia on dead wood. d. Cross section of an apothecium. e. Close-up of the ectal excipulum and medullary excipulum cells. f. Hairs. g. Paraphyses. h–l. Asci (j–l treated with Melzer’s reagent). m–p.Ascospores. Scale bars: d = 200 µm, e = 100 µm, f–p = 20 µm.