Aureobasidium lannaense Senwanna, Kodchasee, J. Kumla & N. Suwannar. 2026, sp. nov.
Authors: Senwanna, Chanokned, Kodchasee, Pratthana, Kathongthung, Chirayut, Samarakoon, Milan C., Khunnamwong, Pannida, Kumla, Jaturong, Suwannarach, Nakarin
Type: Taxonomic treatment
Published: 2026-08-03
Keywords: Biodiversity, Taxonomy, Fungi, Ascomycota, Dothideomycetes, Dothideales, Saccotheciaceae, Aureobasidium, Aureobasidium lannaense

<p><i>Aureobasidium lannaense</i> Senwanna, Kodchasee, J. Kumla & N. Suwannar. sp. nov.</p><p>Fig. 15</p><p><b>Etymology.</b></p><p>Refers to the Kingdom of Lanna, the historic name of northern Thailand, where the flowers containing the new fungus were collected.</p><p><b>Type.</b></p><p>THAILAND • Chiang Mai Province, Mueang District, Suthep, isolated from flosreginae flower (<i>Lagerstroemia speciosa</i>; <i>Lythraceae</i>, <i>Myrtales</i>), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, <i>holotype</i> = CMUB 40135 (preserved in metabolically inactive state), living culture (ex-type) = SDBR-CMU 863 = GMBCC 2511 = TBRC 21785.</p><p><b>Cultural characteristics.</b></p><p>After 14 days of incubation at 25 ° C in the dark, colonies on PDA reaching 25–28 mm diam., surface flat, spreading with filiform, irregular margin, velvety, fluffy, slimy, yellowish white (2 A 2); on MEA reaching 45–54 mm diam., surface flat, spreading, round with radiating margin, velvety, yellowish white (2 A 2), dark gray (3 F 1) to black (tabby appearance); on OA 42–47 mm diam., surface flat, spreading with irregular margin, powdery, light gray (4 D 1) and olive brown (4 E 5: tabby appearance), with light gray (4 D 1) at the margin.</p><p><b>Description.</b></p><p><i><i>Anamorph</i> in vitro</i> dematiaceous hyphomycetes. <i>Vegetative hyphae</i> 3.0–10.0 (– 16.0) μm wide, hyaline to dark brown, branched, septate, smooth, thin-walled, becoming light brown to golden brown, constricted at the septa, thick-walled. <i>Conidiogenous cells</i> (5.0 –) 7.5–15.0 (– 21.0) × (3.0 –) 4.2–7.0 (– 9.0) μm (<i>x ̄</i> = 11.8 × 5.8 μm, <i>n</i> = 25), undifferentiated, intercalary, rarely terminal, producing conidia percurrently from indistinct, short lateral denticles, giving rise to conidia that aggregate in a mucoid mass, or differentiated on hyphae, hyaline to dark brown. <i>Conidia</i> oval, obovoid to ellipsoidal, elongated, or globose to subglobose, hyaline, becoming light brown with age, aseptate, occasionally with an indistinct truncated base and a hilum, guttulate, smooth-walled, (4.0 –) 5.4–9.0 (– 11.0) × 2.5–4.7 (– 6.3) μm (<i>x ̄</i> = 7.0 × 3.8 μm, <i>n</i> = 200), budding occasionally observed. <i>Chlamydospores</i> (7.4 –) 8.7–11 (– 14.9) (<i>x ̄</i> = 10.0 μm, <i>n</i> = 25) µm wide, produced in aerial hyphae, mostly intercalary, solitary or in branched chains, globose to subglobose or ellipsoidal, hyaline becoming golden brown, smooth-, thick-walled, septate, constricted near the septa. <i>Endoconidia</i> absent.</p><p>Fermentation of glucose is negative. <i>D</i> - glucose, galactose, sorbose, <i>N</i> - acetyl glucosamine, ribose, xylose, <i>L</i> - arabinose, <i>D</i> - arabinose (weak), <i>L</i> - rhamnose, sucrose, maltose, <i>α</i> - <i>α</i> - trehalose, methyl- <i>α</i> - <i>D</i> - glucoside (weak), cellobiose, salicin, melibiose, lactose, raffinose, melizitose, glycerol, erythritol, ribitol, glucitol, mannitol, galactitol, <i>myo</i> - inositol, <i>D</i> - glucono- 1, 5 - lactone, <i>D</i> - gluconate, <i>D</i> - glucuronate, <i>D</i> - galacturonic acid, <i>DL</i> - lactate (weak), succinate, citrate, ethanol, and xylitol (weak) are assimilated, but inulin, soluble starch, and methanol are not assimilated. Ammonium sulfate, ethylamine hydrochloride, <i>L</i> - lysine, cadaverine, and creatine are assimilated as sole nitrogen sources. Potassium nitrate and sodium nitrite are not assimilated. After 3 weeks, black sediment formed in <i>D</i> - glucose, <i>D</i> - arabinose, methyl- <i>α</i> - <i>D</i> - glucoside, and <i>D</i> - gluconate, while white sediment observed in lactose.</p><p><b>Cardinal temperatures for growth.</b></p><p>Minimum 10 ° C, optimum in the range of 25 ° C to 30 ° C. No growth at 4 ° C and 37 ° C.</p><p><b>Additional strains examined.</b></p><p>THAILAND • Chiang Mai Province, Mueang District, Suthep, isolated from Indian head ginger flower (<i>Cheilocostus speciosus</i>; <i>Costaceae</i>, <i>Zingiberales</i>), Sep 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 833.</p><p><b>Habitat and distribution.</b></p><p>Flowers of <i>Cheilocostus speciosus</i> and <i>Lagerstroemia speciosa</i>. Known only from northern Thailand.</p><p><b>Notes.</b></p><p>In the multilocus phylogenetic tree, <i>A. lannaense</i> SDBR-CMU 833 and SDBR-CMU 863 (ex-type) formed a distinct monophyletic lineage (100 % MLBS and 0.99 BIPP) that was sister to <i>A. albui</i> and <i>A. floricola</i> (Fig. 2). Comparisons of nucleotide sequences showed that the <i>rpb 2</i> sequence of <i>A. lannaense</i> showed 96.97 % similarity to that of <i>A. albui</i> NRRL 61482 (ex-type) (18 / 594 bp, including gaps) and 96.59 % similarity to that of <i>A. albui</i> SDBR-CMU 866 (32 / 921 bp, including gaps), whereas the <i>tef 1</i> sequence showed 93.93 % similarity to that of <i>A. albui</i> SDBR-CMU 866 (17 / 266 bp, including gaps). The <i>tef 1</i> sequence of <i>A. lannaense</i> showed 93.51 % similarity to that of <i>A. floricola</i> SDBR-CMU 829 (ex-type) (18 / 266 bp, including gaps). Morphological comparison revealed distinct colony characteristics among the three species. On MEA, <i>A. lannaense</i> produced yellowish-white to dark-gray to black colonies, <i>A. floricola</i> produced olive-brown to black colonies with yellowish-white margins, and <i>A. albui</i> produced yellowish-brown to smoke-brown colonies with white margins. On OA, <i>A. lannaense</i> formed light-gray to olive-brown colonies with light-gray margins, differing from <i>A. floricola</i>, which formed yellowish-white to orange-white colonies, and <i>A. albui</i>, which formed whitish-gray colonies with light-gray margins. <i>Aureobasidium lannaense</i> can be distinguished from <i>A. albui</i> and <i>A. floricola</i> by its lack of endoconidium production. Growth at 4 ° C was observed only in <i>A. albui</i>, whereas both <i>A. lannaense</i> and <i>A. floricola</i> did not grow at this temperature. Moreover, the PHI test further supported the genetic distinctiveness of <i>A. lannaense</i>, <i>A. albui</i>, and <i>A. floricola</i>, confirming that they represent distinct species (Fig. 4). <i>Aureobasidium lannaense</i> can be distinguished from <i>A. floricola</i> by its ability to assimilate methyl- <i>α</i> - <i>D</i> - glucoside (Table 1). In addition, <i>A. lannaense</i> differs from <i>A. albui</i> in its ability to assimilate <i>D</i> - arabinose, <i>L</i> - rhamnose, salicin, glycerol, erythritol, ribitol, <i>myo</i> - inositol, ethanol, and xylitol as carbon sources, as well as creatine as a nitrogen source (Jumbam et al. 2025). Therefore, <i>A. lannaense</i> is described herein as a new species.</p>