Pseudoleptodontidium chiangmaiense Thitla, Monkai, Lumyong & Hongsanan, 2025

Pseudoleptodontidium chiangmaiense Thitla, Monkai, Lumyong & Hongsanan sp. nov.

Etymology.

The specific epithet chiangmaiense refers to the type locality, Chiang Mai Province, Thailand.

Holotype.

Thailand • Chiang Mai Province, Mueang Chiang Mai District, Su Thep , on soil in the forest dump-sites, 21 June 2024, T. Thitla & J. Monkai; VR 044 ( SZU 25-007 About SZU , holotype); ex-type living culture, MBSZU 25-005 , dried culture permanently preserved in a metabolically inactive state, SZU 25-007 About SZU .

Colony diam.

(in mm) 14 days, 25 ° C: PDA 36–40 and MEA 31–38.

Culture characteristics.

Colonies at 25 ° C for 14 days on PDA velvety, circular, flat, entire margin; dark green at the centre, greenish-yellow at the middle, white at the margin; soluble pigment absent; reverse dark green to pale yellow, white at the margin (Fig. 7 A View Figure 7 ). Colonies on MEA velvety, circular, flat, entire margin; dark green to black at the centre, yellowish-green to white at the margin; soluble pigment absent; reverse dark green at the centre, pale yellow to white at the margin (Fig. 7 B View Figure 7 ).

Micromorphology.

Mycelium composed of hyaline to black, thin- to thick-walled, smooth, branched, septate, 2–4.5 µm diam. hyphae (Fig. 7 C – L View Figure 7 ). Conidiophores arising from hyphae, solitary, erect, cylindrical, pale brown to dark brown, thick-walled, occasionally roughened on lower part, septate, 7–70 × 2.5–5 µm (Fig. 7 C – G View Figure 7 ). Conidiogenous cells terminal and intercalary on conidiophores, occasionally lateral on hyphae, obclavate, sympodially proliferate, denticulate, hyaline to pale brown, smooth, 0-1 septate, 7.5–26 × 3–5 µm (Fig. 7 C – J View Figure 7 ). Conidia hyaline, smooth, aseptate, subglobose to ellipsoidal, slightly curved, 3–7.5 × 1.5–4 µm (Fig. 7 K View Figure 7 ). Chlamydospores solitary, terminal on hyphae, medium brown to dark brown, smooth, thick-walled, aseptate, subglobose, 6–8 × 4.5–6 µm (Fig. 7 L View Figure 7 ). Sexual morph absent.

Habitat and distribution.

Soil; only known from Chiang Mai Province, Thailand.

Notes.

Pseudoleptodontidium chiangmaiense has a close relationship with Neoleptodontidium aciculare and N. aquaticum (Fig. 4 View Figure 4 ). However, their morphological characteristics are distinct: Ps. chiangmaiense has broader conidiogenous cells (7.5–26 × 3–5 µm) than N. aciculare (15–30 × 2–3 µm) and N. aquaticum (10–30 × 2–2.5 µm) and larger conidia (3–7.5 × 1.5–4 µm) than N. aciculare (3–4 × 1–2 µm) and N. aquaticum (3–4 × 1.5 µm) ( Rao and De Hoog 1986; Hernández-Restrepo et al. 2017). The pairwise nucleotide comparison between Ps. chiangmaiense and N. aciculare revealed differences of 16.38 % (95 / 580 bp, including gaps) in the ITS region and 4.92 % (40 / 813 bp, including gaps) in the LSU region. Additionally, the comparison between Ps. chiangmaiense and N. aquaticum revealed differences of 16.23 % (87 / 536 bp, including gaps) in the ITS region and 4.80 % (39 / 813 bp, including gaps) in the LSU region.