Paragaeumannomyces abietinus Reblova , J. Fourn. & A.N. Mill., 2020

Reblova, Martina, Nekvindova, Jana, Fournier, Jacques & Miller, Andrew N., 2020, Delimitation, new species and teleomorph-anamorph relationships in Codinaea, Dendrophoma, Paragaeumannomyces and Striatosphaeria (Chaetosphaeriaceae), MycoKeys 74, pp. 17-74 : 17

Paragaeumannomyces abietinus Reblova, J. Fourn. & A.N. Mill. sp. nov. Figure 4

Typification.

France - Ariège • Pyrénées Mts., Ustou, Cirque de Cagateille, path up to the La Hillette lake, mixed Abies forest; alt. 1550 m; 18 Jul. 2018; on decaying wood of a trunk of Abies alba ; J. Fournier leg.; J.F. 18057 (holotype: PRA-16323!, ex-type culture CBS 145351).

Etymology.

Referring to the host Abies alba .

Description on the natural substrate.

Teleomorph: Ascomata perithecial, non-stromatic, superficial, solitary or in small groups, 350-450 μm diam, 360-500 μm high, broadly conical, collapsing laterally upon drying, finely roughened, dark reddish-brown, glabrous except for the black conical papilla, with dark brown, stiff, acute setae, 32-40 × 3-4 μm, densely clustered around the ostiole; centrum pink. Ostiole periphysate. Ascomatal wall leathery, three-layered. Outer layer of textura angularis, 33-58 μm thick, consisting of thin-walled, globose, subglobose to polyhedral, dark ginger-brown to reddish-brown cells, 6.5-11 μm diam, grading into smaller cells towards the exterior. Middle layer of textura prismatica, 18-25 μm thick, composed of thick-walled, polyhedral, dark brown, melanised cells. Inner layer of textura prismatica, 10-15 μm thick, composed of thin-walled, flattened and elongated hyaline cells. Paraphyses abundant, hyaline, sparsely branched, septate, 4.5-7 μm wide, tapering to 2-2.5 μm, longer than the asci. Asci (185-)195-240 × 12-14.5(-15.5) μm (mean ± SD = 209.2 ± 12.0 × 14.1 ± 0.8 μm), (145-)155-205 µm (mean ± SD = 172.6 ± 14.3 μm) long in the sporiferous part, cylindrical-fusiform, stipitate, apically rounded, ascal apex non-amyloid with a distinct apical annulus 3-3.5 μm wide, 2-3 μm high. Ascospores (62-)65-87 × (3.5-)4-5.5 μm, filiform to cylindrical, straight or slightly curved to sigmoid, hyaline, light pink in mass, with dextrinoid reaction in Melzer’s reagent turning reddish-brown except for the end cells which remain hyaline, (5-)7-9(-11)-septate, septa often unevenly distributed, not constricted or slightly constricted at the septa, especially at the septa above and below the middle, asymmetrical, rounded at the apical end, tapering towards the basal end, with one or two guttules in each cell, 2-3-seriate or 4-seriate and partially overlapping or 4-seriate forming two fascicles end to end. Anamorph: Unknown.

Culture characteristics.

On CMD colonies 10-11 mm diam, circular, slightly convex, margin entire to weakly fimbriate, lanose, beige-brown with a dark brown outer zone of submerged growth, dark brown pigment diffusing from the colony margin to agar; reverse dark brown to black. On MLA colonies 12-15 mm diam, circular, slightly convex, margin entire, lanose, floccose, cobwebby at the margin, beige-brown with a dark brown outer zone of submerged growth, brown pigment diffusing from the colony margin to agar; reverse dark brown. On OA colonies 8-9 mm diam, circular, convex, margin entire, lanose, beige-brown, with a paler outer ring; reverse brown. On PCA colonies 14-15 mm diam, circular, convex, margin entire, lanose, floccose, cobwebby towards the margin, beige, pale brown towards the margin; reverse brown. Sporulation absent on all media, even after prolonged incubation (> 3 mo).

Other specimen examined.

Ukraine • Carpathian Mts., Kvasi, Bliznica near Rachiv, right bank of the upper flow of the Tisa river; alt. 1000 m; 28 Jun. 1997; on decaying wood of Abies alba ; M. Réblová leg.; M.R. 946 (PRA-16324). • Ibid.; M.R. 947 (PRA-16325). • Ibid.; M.R. 959 (PRA-16326). Ukraine • Carpathian Mts., Massif Boržava, Guklivij; 21 Jul. 1998; on decaying wood of Abies alba ; M. Réblová leg.; M.R. 1309 (PRA-16327).

Habitat and distribution.

All specimens of P. abietinus occur on decaying wood of Abies alba . The species has been collected in mountain areas and is known in Europe in France and Ukraine.

Notes.

Attempts to cultivate this species were unsuccessful for the Ukrainian specimens; the ascospores germinated over five days with long inflated germ tubes from both ends but did not grow after isolation on agar medium. The axenic culture derived from the ascospore isolate of the French material yielded sterile mycelium only.

Paragaeumannomyces abietinus is similar to P. rubicundus and P. lapazianus in reddish-brown ascomata, the arrangement of setae around the ostiole and distribution in the north temperate region. Paragaeumannomyces rubicundus ( Huhndorf and Fernández 2005) can be distinguished from the present species in having 7-septate, longer (80-100 × 3.5-4.2 μm) ascospores and red surface crystals; P. lapazianus has 7-septate ascospores and a broader range of ascospore lengths including shorter and broader ascospores [(45-)50-100(-120) × (3-)4.5-6(-7) µm] and larger ascomata [(400-)500-950 µm diam, 525-825(-1025) µm high]. In the ITS-28S phylogenetic tree (Fig. 2 ), P. abietinus was clustered with P. granulatus (New Zealand) and P. smokiensis (USA). These species are morphologically highly similar; they share glabrous, dark brown to reddish-brown ascomata except for the black papilla containing short, appressed setae, and ascospores exhibiting a dextrinoid reaction in Melzer’s reagent. Paragaeumannomyces granulatus differs from P. abietinus in longer [(90-)95-123.5 μm], (7-)11-13-septate ascospores, while P. smokiensis is distinguished from the latter species by shorter and slightly narrower asci [(134-)140-174(-189) × 11-13(-14) μm] and ascospores with more septa (9-11-septate).

Figures

Figure 2. Combined phylogeny using ITS and 28 S of 35 members of Paragaeumannomyces. Species names given in bold are new species; T and PT indicate ex-type and ex-paratype strains. Thickened branches indicate branch support with MLBS = 100 %, PP values = 1.0 and MP = 100 %. Branch support of nodes ≥ 75 % ML and MPBS, and ≥ 0.95 PP is indicated above branches.

Figure 4. Paragaeumannomyces abietinus. A, B ascomata C, D, F vertical section of ascomal wall E vertical section of the ascomal wall and papilla with apical setae G, H ascospores I, J asci K, L ascal apex with apical ring M paraphyses N colonies on CMD, MLA, OA and PCA after 4 wk (from left to right). Images: PRA- 16327 (A); CBS 145351 (B, F-L, N); PRA- 16324 (C); PRA- 16325 (D, E, M). Scale bars: 250 μm (A, B); 200 μm (C); 50 μm (D-F); 20 μm (I, J, M); 10 μm (G, H, K, L); 1 cm (N).