Chaetocapnodium magnum Czachura, Janik & Piątek, 2015

Czachura, Paweł, Janik, Paulina & Piątek, Marcin, 2025, Chaetocapnodium magnum and Chaetocapnodium polonicum from conifer resins disclose an unknown lifestyle in the Capnodiales (Dothideomycetes), MycoKeys 119, pp. 315-333 : 315-333

Chaetocapnodium magnum Czachura, Janik & Piątek sp. nov.

Figs 2 , 3

Etymology.

The name refers to the pycnidial size, which is the largest among all currently known species of this genus.

Typus.

Poland • Podkarpackie Province, Krosno County, the Modrzyna Reserve , on resin of Larix decidua ssp. polonica , 22 Oct. 2020, leg. P. Czachura (holotype: KRAM F-60024 ; culture ex-type: CBS 153154 = P 0022 ) .

Description.

Hyphae hyaline (when young), pale brown or brown, smooth or verruculose, branched, septate, mostly constricted at septa, sometimes anastomosing, 2–7.5 μm wide. Pycnidia globose, subglobose, or pyriform, formed intercalary or terminal on hyphae; peridium composed of pale brown, brown, or pale olivaceous pseudoparenchymatous cells arranged in textura angularis, 44.5–209 × 35.5–158 μm. Setae absent or present, aseptate or one-septate, dark brown, rarely branched, 10.5–26 μm long. Ostiole absent or present, not well-developed or well-developed. Conidia release from ostiole or by rupture of peridium, hyaline or subhyaline, aseptate, globose or subglobose, smooth, 2.5–3.7 × 2.4–3.2 μm.

Culture characteristics.

Colonies on MEA convex, greenish black, greenish grey, or pale greenish grey, reaching 16 mm diam. after 2 weeks at 15 ° C and 13 mm diam. after 2 weeks at 25 ° C, margin lobate, reverse greenish black. Colonies on OA flat, greenish black, reaching 9 mm diam. after 2 weeks at 15 ° C and 12 mm diam. after 2 weeks at 25 ° C, margin nearly entire, reverse greenish black. Colonies on PDA convex, olivaceous black with fluffy, grey olivaceous aerial mycelium, reaching 15 mm diam. after 2 weeks at 15 ° C and 12 mm diam. after 2 weeks at 25 ° C, margin irregular from undulate to lobate, reverse olivaceous black. Colonies on SNA flat, grey olivaceous, with sparse aerial mycelium, reaching 11 mm diam. after 2 weeks at 15 ° C and 11 mm diam. after 2 weeks at 25 ° C, margin fimbriate, reverse grey olivaceous.

Additional specimen examined.

Poland • Świętokrzyskie Province, Kielce County, the Świętokrzyski National Park, the strict protection area Psarski Dół , on resin of Abies alba , 16 Oct. 2020, leg. P. Czachura ( KRAM F-60025 ; culture: CBS 153155 = P 0023 ) .

Notes.

Chaetocapnodium magnum formed a highly distinct phylogenetic lineage within representatives of the genus Chaetocapnodium . Morphologically, Chaetocapnodium magnum differs from the rest of the Chaetocapnodium species by having the largest pycnidia amongst all currently known Chaetocapnodium species. Moreover, all other species have straight setae in contrast to the occasionally branched setae observed in Chaetocapnodium magnum , a feature that is observed in the genus Chaetocapnodium for the first time.

Figures

Figure 2. Morphology of cultures of Chaetocapnodium magnum (CBS 153154) after 2 weeks at 25 ° C. A. B. Colony on MEA; C, D. Colony on OA; E, F. Colony on PDA; G, H. Colony on SNA.

Figure 3. Morphology of Chaetocapnodium magnum (CBS 153154). A – D. Pycnidia; E. Ruptured peridium with released conidia; F. Ostiole not well-developed; G, H. Ostioles well-developed with released conidia; I – K. Setae; L. Conidia. Scale bars: 100 µm (A, B); 10 µm (C – L).