Pseudolomaantha thailandica J. Y. Zhang, Y. Z. Lu & K. D. Hyde, 2025

Pseudolomaantha thailandica J. Y. Zhang, Y. Z. Lu & K. D. Hyde sp. nov.

Fig. 2 View Figure 2

Etymology.

The name refers to the country “ Thailand ” from where the holotype was collected.

Holotype.

MFLU 24-0394 View Materials .

Description.

Saprobic on dead stems of bamboo in a terrestrial habitat. Sexual morph Undetermined. Asexual morph Hyphomycetous. Colonies on natural substrate superficial, effuse, scattered, hairy, dark brown, with gold glistening on the apex of conidia. Mycelium partly immersed, partly superficial, composed of septate, mostly unbranched, smooth, brown hyphae. Conidiophores 176–275 × 6–9 (– 11) µm (x ̄ = 219.6 × 7.5 µm, n = 20), macronematous, mononematous, solitary, cylindrical, straight or slightly flexuous, septate, black at the base, paler to light brown or brown towards the apex. Conidiogenous cells 12–22 × 5.5–7 µm (x ̄ = 16.4 × 6.1 µm, n = 20), integrated, terminal, holoblastic, monoblastic, cylindrical, brown or pale brown at the apex. Conidia (92.5 –) 95–112.5 × 12.5–15.5 µm (x ̄ = 105.8 × 13.8 µm, n = 25), acrogenous, solitary, dry, pyriform to obclavate, rostrate, tapering to the round apex, truncate at base, basal cell conical-truncate, straight or slightly curved, up to 12 - septate, with distoseptate, not constricted or slightly constricted at septum, guttulate, brown, two upper cells subhyaline to hyaline, with gold and glistening appendages around the apex of the conidia.

Culture characteristics.

Conidia germinating on WA within 15 h and germ tube produced from the ends of conidia. Colonies growing on PDA, reaching 22–26 mm in 20 days at 26 ° C, circular, edge entire, umbonate with a knobby protuberance, white from above; zonate, yellowish orange in the center, grayish olive to yellowish towards to margin from below.

Material examined.

Thailand • Chiangmai Province, Mushroom Research Center ( MRC), on dead stems of bamboo, 11 September 2020, H. W. Shen, Y 205-1 ( MFLU 24–0394 View Materials , holotype), ex-type living culture, MFLUCC 24–0521 View Materials .

Notes.

BLAST results for the ITS and LSU sequence data of Pseudolomaantha thailandica show 88.39 % similarities with Caligospora dilabens (CBS 735.83) and 97.81 % similarities with Craspedodidymum elatum ( NN 042874), respectively. Phylogenetic analysis shows that Pseudolomaantha thailandica forms a distinct lineage basal to Caliciastrum, Caligospora, and Craspedodidymum with statistical support (79 % ML / 0.97 PP, Fig. 1 View Figure 1 ). Members of Caliciastrum, Caligospora, and Craspedodidymum are characterized by phialidic conidiogenous cells with open, vase-shaped collarettes, and brown or hyaline conidia. In contrast, our new species has a sporidesmium-like asexual morph with non-phialidic conidiogenous cells ( Figueroa et al. 2018; Wu and Diao 2022; Réblová and Nekvindová 2023). Morphologically, Pseudolomaantha resembles Lomaantha in having macronematous, mononematous conidiophores, integrated holoblastic conidiogenous cells, and acrogenous, obclavate, rostrate, distoseptate, pale brown to brown conidia ( Wu and Zhuang 2005; Wu and Diao 2022; Réblová and Nekvindová 2023). However, the two genera are phylogenetically distinct. Additionally, Lomaantha species have conidiogenous cells that are determinate or extend percurrently a few times, as well as conidia that lack or bear filiform, extended, simple or branched apical appendages and distinct septal pores ( Wu and Zhuang 2005; Wu and Diao 2022; Réblová and Nekvindová 2023). In contrast, Pseudolomaantha has determinate conidiogenous cells, conidia with golden, glistening appendages at the conidial apex, and lack distinct pores in the distosepta. Based on the combination of morphological and phylogenetic evidence, Pseudolomaantha is introduced as a new genus to accommodate P. thailandica within Chaetosphaeriaceae .