Melanocucurbitaria uktampratovii D. Pem, R. Jeewon, Gafforov & K. D. Hyde 2025, sp. nov.

Melanocucurbitaria uktampratovii D. Pem, R. Jeewon, Gafforov & K. D. Hyde sp. nov. Fig. 2 Etymology. uktam-pratovii (Lat.) in honor of Uzbek scientist, Prof. Uktam Pratovich Pratov (1934–2018), for his contribution to the botanical research in Central Asian countries. Description. Saprobic on dead branches of Salvia karelinii J. B. Walker. Sexual morph: Ascomata 200–500 μm wide, 250–400 μm high scattered to gregarious, immersed or semi erumpent, carbonaceous, dark brown to black, globose to subglobose, papillate. Ostiole indistinct, with a small papilla. Peridium 25–35 μm, 3–5 layers, inner layers composed of subhyaline to light brown cells of textura angularis, outer layer composed of irregular, thick-walled, highly pigmented dark-brown cells of textura angularis. Hamathecium 1.5–2.0 µm (n = 10) wide, comprising numerous, filamentous, branched, anastomosing, septate, hyaline, pseudoparaphyses. Asci 160–175 × 13–14 μm (x ̄ = 164.0 × 13.6 µm, n = 10), 8 - spored, bitunicate, fissitunicate, cylindrical, pedicellate, apically rounded, with an ocular chamber. Ascospores 18–25 × 7–9 μm (x ̄ = 20.8 × 7.7 µm, n = 10), uniseriate, ellipsoidal, muriform, 4–6 transverse septa, with 3–7 longitudinal septa, slightly constricted at the septa, more at the middle septum, at first hyaline turning golden brown to dark-brown at maturity, obtuse at the ends, lacking a mucilaginous sheath, smooth and thick-walled. Asexual morph: Undetermined. Culture characteristics. Colonies on MEA, reaching 20–25 mm diam. after 3 weeks at 25 ° C, medium dense in middle, medium sparse at the edges, irregular, umbonate, velvety to floccose, undulated edges, smooth. Known distribution (based on molecular data). Uzbekistan (Wanasinghe et al. 2018; this study). Confirmed hosts (based on molecular data). Acer pubescens Franch (Sapindaceae) (Wanasinghe et al. 2018), Salvia karelinii (Lamiaceae) (this study). Material examined. Uzbekistan • Surkhandarya Province, Baysun District, Omonxona Village, South-Western Hissar Mountains, on dead branches of Salvia karelinii (Lamiaceae), 13 May 2016, Y. Gafforov, I. Urinboev, YG-S 29-3 (TASM 6176, holotype; MFLU 17-0071, isotype), ex-type living culture MFLUCC 17-1953. GenBank numbers. LSU: PQ 453820, ITS: PQ 453018, TEF- 1: PQ 441826. Notes. The morphology of our collection (TASM 6176) resembles the type species Melanocucurbitaria uzbekistanica (TASM 6109) in its scattered to gregarious, dark brown to black, globose to subglobose, papillate ascomata, cylindrical, pedicellate asci and ellipsoidal, muriform ascospores (Wanasinghe et al. 2018). Our collection is different from the type species M. uzbekistanica in having smaller ascomata (200–400 × 250–400 μm vs. 500–700 × 550–750 μm), smaller asci (160–175 × 13–14 μm vs. 280–300 × 19–23 µm), smaller ascospores (18–25 × 7–9 μm vs. 37–47 × 17–19 µm) and number of septa (4–6 transverse septa, 3–7 longitudinal septa vs. 6–8 transverse septa, 3–4 longitudinal septa) (Wanasinghe et al. 2018). Melanocucurbitaria uzbekistanica also differs from M. uktampratovii in having black, semi-immersed ascomata, ostiole filled with brown cells, ascospores which are pale brown at maturity, broadly rounded at the ends, surrounded by a mucilaginous sheath when immature while M. uktampratovii has immersed or semi erumpent ascomata, indistinct ostiole, with a small papilla, ascospores which are dark brown at maturity, obtuse at the ends and lacking a mucilaginous sheath. According to the multi-gene phylogeny, our collection clusters with the isolate of Melanocucurbitaria uzbekistanica (MFLUCC 17-0829) in 90 % ML and 1.00 BYPP supported clade. The nucleotide base comparison of LSU, ITS and TEF- 1 regions showed that our strain (TASM 6176) differs from the type strain of M. uzbekistanica (MFLUCC 17-0829) by 23 / 865 bp (2.65 %), 15 / 439 bp (3.41 %) and 20 / 571 bp (3.5 %), respectively. Therefore, we introduce our collection as a new species based on morphology and phylogeny. The phylogenetic placement of our strain (TASM 6176) is shown in Fig. 1.