Rhodoveronaea guizhouensis H. Zhang & J. Ma sp. nov.

Fig. 3

Etymology.

The specific epithet ‘ guizhouensis ’ refers to the locality “ Guizhou Province ”, from where the holotype was collected.

Holotype.

GZAAS 25-0663.

Description.

Saprobic on decaying submerged wood in a freshwater habitat. Sexual morph Undetermined. Asexual morph Hyphomycetous. Colonies on wood effuse, hairy, scattered or aggregated, brown. Mycelium partly superficial, partly immersed, composed of branched, septate, guttulate, smooth-walled, hyalina to brown hyphae. Conidiophores 211–268 × 4.5–6.3 μm (x ̄ = 234 × 5.2 μm, n = 25), macronematous, mononematous, erect, flexuous, solitary, cylindrical, smooth-walled, septate, unbranched, black brown, mid brown, paler towards the apex. Conidiogenous cells polyblastic, integrated, terminal, determinate, sympodial, forming a rachis with subdenticulate loci, flexuous, pale brown to subhyalina, pigmented, with inconspicuous denticles. Conidia 11.5–17 × 4.3–6 μm (x ̄ = 13.8 × 5.2 μm, n = 25), acropleurogenous, aggregated in slimy masses, ellipsoidal to narrowly obovoid, 1–3 - septate, mostly 3 - septate, smooth-walled, pale yellowish brown, guttulate, thin-walled, sometimes slightly constricted at the septa.

Culture characteristics.

Conidia germinating on PDA within 11 hours, producing germ tubes from the conidial body. Colonies on PDA are circular with a raised surface and entire margin, reaching 27 mm in diameter after 32 days at room temperature (approximately 25 ° C), and are white, reddish brown to black in color on both the surface and reverse sides.

Material examined.

China • Guizhou Province, Chishui City, Chishui River, on decaying submerged wood in a freshwater habitat, 10 October 2024, Hong Zhang & Jian Ma, CSF 2 (GZAAS 25-0663, holotype), ex-type living cultures GZCC 25-0633; Ibid., CSF 9 (GZAAS 25-0664, paratype), living culture GZCC 25-0634.

Notes.

In our phylogenetic tree (Fig. 1), our isolates (GZCC 25-0633 and GZCC 25-0634) formed a sister clade to Rhodoveronaea lignicola (GZCC 23-0624) with 92 % ML and 1.00 BYPP support. Rhodoveronaea guizhouensis (GZAAS 25-0663) can be distinguished from R. lignicola (GZAAS 23-0612) by its longer conidiophores (211–268 μm vs. 75–125 μm), longer conidia (up to 17 μm vs. 9–13.5 μm) (Chen et al. 2024). Moreover, base pair comparison of Rhodoveronaea guizhouensis (GZCC 25-0633) and R. lignicola (GZCC 23-0624) shows 30 / 528 bp differences in ITS (5.7 %, gaps 5 bp), 7 / 862 bp differences in LSU (0.8 %, gaps 2 bp), 3 / 910 bp differences in SSU (0.3 %, without gap), 39 / 887 bp differences in tef 1 - α (4.4 %, without gap), and 69 / 803 bp differences in rpb 2 (8.6 %, without gap). Therefore, based on DNA molecular data and morphological characteristics, we introduce Rhodoveronaea guizhouensis as a novel species.