Cladosporium submersum Iturrieta-Gonzalez , Dania Garcia , Gene, 2021

Iturrieta-Gonzalez, Isabel, Garcia, Dania & Gene, Josepa, 2021, Novel species of Cladosporium from environmental sources in Spain, MycoKeys 77, pp. 1-25 : 1

Cladosporium submersum Iturrieta-Gonzalez, Dania Garcia, Gene sp. nov. Fig. 8

Etymology.

Name refers to the aquatic habitat where the substrate (submerged plant material) of the fungus was collected (submersus = submerged, verb in participle, from submergere).

Type.

Spain, Catalonia, Tarragona province, Cornudella del Montsant, Siurana’s swamp, submerged plant material, Feb. 2018, I. Iturrieta-González, E. Carvalho & J. Gené (holotype CBS H-24474; cultures ex-type FMR 17264, CBS 146923).

Description.

Mycelium in vitro superficial and immersed, composed of septate, branched, subhyaline to pale brown, smooth-walled to verruculose hyphae, 1-3 μm wide. Conidiophores dimorphic, micronematous or macronematous, arising laterally and terminally from hyphae, erect to slightly flexuous, nodulose, geniculate at the apex, septate, unbranched, occasionally branched with small prolongations just below the septum, up to 77 μm long, 3-5 μm wide, pale brown to brown, smooth to verruculose. Conidiogenous cells integrated, terminal and intercalary, geniculate, nodulose, 11-28 × 3-6 μm, bearing up to five conidiogenous loci, darkened and refractive. Ramoconidia rarely formed, 0(-1)-septate, sometimes constricted at the septum when present, cylindrical to subcylindrical, 10.5-24 × 4.5-7 μm [av. ( ± SD) 16 ( ± 3.6) × 6.1 ( ± 1.03)], pale brown, verruculose to verrucose. Conidia forming short branched chains, pale brown, verrucose, occasionally verruculose, with protuberant and slightly darkened hila; small terminal conidia aseptate, ovoid to ellipsoidal, 6-12.5 × 3.5-7 μm [av. ( ± SD) 7.8 ( ± 1.63) × 4.8 ( ± 0.79)]; intercalary conidia and secondary ramoconidia 0-1-septate, ellipsoidal or subcylindrical, 7.5-16 × 4.5-8 μm [av. ( ± SD) 11 ( ± 2.18) × 5.7 ( ± 0.99)].

Culture characteristics

(14 d at 25 °C). Colonies on OA reaching 22-23 mm diam., brownish gray to olive brown (4E2/4E4), umbonate, velvety, aerial mycelium scarce, margin slightly irregular and fimbriate; reverse dark green to olive brown (6F8/4E3). On PDA attaining 26-28 mm diam., olive (3F3/1F5), slightly umbonate, radially folded, velvety, aerial mycelium scarce, margin irregularly undulate; reverse dark green (30F9) to black with brownish red (9C6) areas observed between 15 and 20 °C and a white edge. On SNA reaching 21-22 mm diam., olive (3E3), slightly umbonate, loosely cottony, margin fimbriate; reverse dark olive brown to golden gray (3E3/4C2).

Cardinal temperature for growth.

Optimum 20 °C, maximum 35 °C, minimum 5 °C.

Distribution.

Spain.

Notes.

Cladosporium submersum is related to C. subcinereum , and morphologically differentiated by having shorter conidiophores (up to 77 μm vs up to 140 μm), shorter conidiogenous cells (11-28 vs 16-38 μm), shorter ramoconidia (10.5-24 vs 19-59 μm), and longer terminal conidia (6-12.5 vs 5-7 μm), which are ovoid to ellipsoidal in our species and globose to subglobose in C. subcinereum ( Sandoval-Denis et al. 2016). In addition, C. submersum exhibited a colony reverse on PDA with brownish red areas, a feature that is absent in C. subcinereum .

Figures

Figure 8. Cladosporium submersum (ex-type FMR 16264) a-c colonies on PDA (front at 25 ° C and reverse at 20 ° C), OA and SNA at 25 ° C after 14 days d, e conidiophores and conidia f conidia. Scale bars: 10 mm (a-c); 10 μm (d-f).