Tubeufia nigroseptum H.W. Shen, L.L. Li, H.Y. Su & Z.L. Luo, 2022

Li, Long-Li, Shen, Hong-Wei, Bao, Dan-Feng, Lu, Yong-Zhong, Su, Hong-Yan & Luo, Zong-Long, 2022, New species, Parahelicomyces yunnanensis sp. nov. and Tubeufia nigroseptum sp. nov. from freshwater habitats in Yunnan, China, Phytotaxa 530 (1), pp. 21-37 : 29

Tubeufia nigroseptum H.W. Shen, L.L. Li, H.Y. Su & Z.L. Luo sp. nov. FIGURE 3

Index Fungorum number: IF 558686 ; Facesoffungi number: FOF 10260 ;

Etymology: —Referring to the mature conidia of this fungus with dark septa.

Holotype: —KUN-HKAS 115528

Saprobic on decaying wood in a freshwater stream. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substratum superficial, effuse, gregarious, white to pale brown. Mycelium composed of partly immersed, partly superficial, hyaline to pale brown, septate, branched hyphae, with masses of crowded, glistening conidia. Conidiophores macronematous, mononematous, erect, cylindrical, mostly unbranched, 0–2-septate, 30–65 µm long, 3–5 µm wide, hyaline to pale brown, smoothwalled. Conidiogenous cells holoblastic, monoblastic, integrated, terminal, cylindrical, truncate at apex after conidial secession, hyaline to pale brown, smooth-walled. Conidia solitary, acrogenous, helicoid, rounded at tip, 34–62 µm diam, and conidial filaments 5–10 µm wide in the broadest part (x = 42 × 7 µm, n = 40), 142–187 µm long, tightly coiled 2–3 times, not becoming loose in water, 16–30 septate, the young conidia have indistinct septate, darkened and slightly constricted at the septa when mature, guttulate, hyaline when young, brown to dark brown when aged, smooth-walled. Sexual morph: Undetermined.

Culture characteristics: — Conidia germinating on PDA and germ tubes produced from conidia within 12 h. Colonies growing on PDA, circular, with flat surface, edge entire, reaching 28 mm in 3 weeks at room temperature, pale brown to brown in MEA medium. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown, smooth-walled.

Material examined: — CHINA, Yunnan province, Nujiang River, on submerged decaying wood, March 2017, Hong-Wei Shen , S-881 (KUN-HKAS 115528, holotype), ex-type living culture, CGMCC 3.20430 .

Notes: —Morphologically, Tubeufia nigroseptum resembles T. machaerinae in having similar shape of conidia, coiled 2–3 times and conidiogenous cells. However, T. nigroseptum differs from T. machaerinae in having less number of conidial septa (16–30 vs. 28–35), darkened septa and hyaline conidia when young, pale brown when aged. Furthermore, multi-gene phylogenetic result showed that our new taxon is distinct from T. machaerinae .

In our phylogenetic analysis, Tubeufia nigroseptum clusters with T. brunnea , T. hechiensis and T. taiwan ensis with high bootstrap support (100% ML and 1.00 PP). Following Jeewon & Hyde (2016) for delimitation of new species, there are 29 noticeable nucleotide differences among the 554 nucleotides between T. taiwan ensis and Tubeufia nigroseptum . Tubeufia nigroseptum resembles T. brunnea in having flexuous, conidiophores, multi-septate, guttulate, smooth-walled conidia, not becoming loose in water. However, T. nigroseptum has a tight spiral, brown conidia at maturity, have black septum. Therefore, we identified the isolate as new species of Tubeufia .

Figures

FIGURE 3. Tubeufia nigroseptum (KUN-HKAS 115528, holotype). a Colony on decaying wood. b Conidiophores, conidiogenous cells and conidia. c Conidiogenous cells. d–f Conidiophores with attached conidia. g–l Conidia. m Germinating conidium. n–o Colony on PDA from above and below. Scale bars: b, d–f = 30 μm, c = 10 μm, g–m = 20 μm.