Penicillium chiangmaiense Thitla, Monkai, Lumyong & Hongsanan 2025, sp. nov.

Penicillium 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, Mae Rim District, Mae Sa, on soil in the forest dump-sites, 27 June 2024, T. Thitla & J. Monkai; VR 005 (SZU 25-006, holotype); ex-type living culture, MBSZU 24-009, dried culture permanently preserved in a metabolically inactive state, SZU 25-006. Colony diam. (in mm) 7 days, 25 ° C: CREA 40–44, CYA 50–52, CYAS 35–38, CZ 48–49, DG 18 34–39, MEA 47–51, MEAbl 51–53, OA 53–54, PDA 49–50 and YES 32–38. 7 days, 30 ° C: CYA 59–61. 7 days, 37 ° C: CYA 55–56. Culture characteristics. Colonies at 25 ° C for 7 days on CREA thin colonies; acid production absent (Fig. 6 A). Colonies on CYA and CYAS wrinkled texture, velvety, circular, flat, entire margin; white mycelia; soluble pigment absent; reverse light brown (Fig. 6 B, C). On CZ, thin colonies, circular, flat, filamentous margin; white mycelia; soluble pigment absent; reverse white (Fig. 6 D). On DG 18, wrinkled texture, velvety, circular, flat, entire margin; white mycelia; soluble pigment absent; reverse white to pale yellow (Fig. 6 E). Colonies on MEA and MEAbl smooth texture, circular, flat, entire margin; pale yellow at the centre, white at the margin; soluble pigment absent; reverse pale brown to white (Fig. 6 F, G). On OA, smooth textured, velvety, circular, flat, entire margin; white mycelia; soluble pigment absent; reverse light yellow to white (Fig. 6 H). Colonies on PDA circular, flat, smooth texture, entire margin; white mycelia; soluble pigment absent; reverse white to light yellow (Fig. 6 I). Colonies on YES circular, flat, wrinkled texture, velvety, entire margin; white mycelia; soluble pigment absent; reverse brownish-yellow (Fig. 6 J). Sporulation abundantly produces on DG 18, MEA and MEAbl media. Sclerotia produces MEA, MEAbl and OA (Fig. 6 P). Micromorphology. Conidiophores monoverticillate, sometimes divaricate. Stipes hyaline, smooth – walled, 80–270 × 2–3 µm (Fig. 6 K – N). Phialides terminal, ampulliform, hyaline, smooth – walled 6–17 × 2–3.5 µm (Fig. 6 K – N). Conidia globose to subglobose, 2–4 µm diam., smooth, hyaline (Fig. 6 K – O). Sclerotia pale brown to brown, globose to irregular, 180–260 µm diam. (Fig. 6 P). Sexual morph absent. Additional strain examined. Thailand • Chiang Mai Province, Mae Rim District, Mae Sa, on soil in the forest dump-sites, 27 June 2024, T. Thitla & J. Monkai; CMUVR 005-2; living culture, MBSZU 24-010, dried culture permanently preserved in a metabolically inactive state, CMUVR 005-2. Habitat and distribution. Soil; only known from Chiang Mai Province, Thailand. Notes. Penicillium section Lanata - Divaricata was established by Thom (1930) to include species with biverticillate conidiophores, which usually contain a main conidiophore axis and metulae that diverge (referred to as divaricate conidiophores), as well as broadly spreading colonies (Houbraken and Samson 2011; Pangging et al. 2021). Species within this section have been isolated from various sources, including soil, air, fluvial sediments and plants (Nóbrega et al. 2024). Currently, the section is divided into five series: Dalearum, Janthinella, Oxalica, Rolfsiorum and Simplicissima (Ansari et al. 2023; Visagie et al. 2024 a). Penicillium chiangmaiense is classified within section Lanata - Divaricata, series Janthinella. In the phylogenetic tree (Fig. 3), the new species is closely related to P. brefeldianum, P. limosum and P. michoacanense. However, P. brefeldianum produces sexual structures on cornmeal agar and P. limosum produces on CZ, MEA and OA, while P. chiangmaiense does not exhibit any sexual features (Dodge 1933; Ueda 1995). Furthermore, the growth rate of P. limosum on MEA (42 mm in 14 days) was slower than that of P. chiangmaiense (47–51 mm in 7 days) (Ueda 1995). In the case of P. michoacanense, the stipes (15–60 × 1–1.5 µm) and phialides (4–5 × 1.5 µm) were shorter than those of P. chiangmaiense (stipes 80–270 × 2–3 µm; phialides 6–17 × 2–3.5 µm) (Rodríguez-Andrade et al. 2021). Moreover, P. michoacanense produced weak acid on CREA, while P. chiangmaiense does not produce it (Rodríguez-Andrade et al. 2021). Additionally, the pairwise nucleotide comparison of P. chiangmaiense with related species revealed significant differences. The comparison of P. chiangmaiense to P. brefeldianum showed 0.90 % (5 / 556 bp) difference in ITS, 4.73 % (21 / 444 bp) in TUB, 4.28 % (24 / 561 bp) in CAM and 1.46 % (11 / 755 bp) in RPB 2, including gaps. Differences in P. chiangmaiense and P. limosum were 1.09 % (6 / 548 bp) in ITS, 5.00 % (22 / 440 bp) in TUB, 6.28 % (35 / 557 bp) in CAM and 0.93 % (7 / 755 bp) in RPB 2, including gaps. In comparison between P. chiangmaiense and P. michoacanense, the differences were 0.73 % (4 / 548 bp) in ITS, 2.84 % (11 / 388 bp) in TUB, 8.35 % (34 / 407 bp) in CAM and 1.61 % (12 / 745 bp) in RPB 2, including gaps.