Paragaeumannomyces sabinianus Reblova & 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 sabinianus Reblova & A.N. Mill. sp. nov. Figure 9

Typification.

USA - Tennessee • Sevier Co., Great Smoky Mountains National Park, Twin Creeks, Twin Creeks Nature Trail, near ATBI plot; alt. 549 m; 11 Oct. 2006; on decaying wood; A.N. Miller & P. Chaudhary leg.; A.N.M. 1011 (holotype: ILLS00121384!).

Etymology.

The species epithet is proposed in honour of Sabine M. Huhndorf for her contribution to mycology and studies in Chaetosphaeria .

Description on the natural substrate.

Teleomorph: Ascomata perithecial, non-stromatic, superficial, usually solitary or in small groups, 250-300(-400) μm diam, 280-320 μm high, subglobose to broadly conical, rarely collapsing laterally upon drying, finely roughened, dark reddish-brown except for a black indistinct papilla, setose, setae 30-41.5 × 4-5 μm, dark brown, stiff, acute, scattered over entire ascoma, shorter and narrower setae 16.5-35 × 2.5-3 μm densely aggregated around the ostiole. Ostiole periphysate. Ascomatal wall leathery, three-layered. Outer layer of textura angularis, 32-53 μm thick, consisting of thin-walled, globose to subglobose, dark orange-brown to reddish-brown cells, 11.5-28 μm diam. Middle layer of textura prismatica, 12-22 μm thick, composed of thick-walled, polyhedral, dark brown, melanised cells. Inner layer of textura prismatica, 3-5 μm thick, composed of thin-walled, flattened and elongated hyaline to subhyaline cells. Paraphyses abundant, hyaline, sparsely branched, septate, 3.5-4.5(-6) μm wide, tapering to 2-2.5 μm, longer than the asci. Asci (154-)161-189 × (11-)12.5-14.5(-15.5) μm (mean ± SD = 174.2 ± 8.7 × 13.0 ± 0.8 μm), (130-)144-165 µm (mean ± SD = 155.2 ± 8.3 μm) long in the sporiferous part, cylindrical-fusiform, stipitate, apically broadly rounded to obtuse, ascal apex non-amyloid with a distinct apical annulus 2.5-3 μm wide, 1.5-2 μm high. Ascospores (64.5-)68.5-86.5(-88.5) × (3-)3.5-4.5 μm, (mean ± SD = 79.1 ± 5.3 × 4.0 ± 0.3 μm), filiform to cylindrical, straight or slightly curved to sigmoid, hyaline, 7-septate, septa often unevenly distributed, not constricted at the septa, asymmetrical, broadly rounded at the apical end and tapering towards the narrowly rounded basal end, with one or two guttules in each cell, 2-3-seriate, rarely 4-seriate, partially overlapping, with a negative or weak dextrinoid reaction in Melzer’s reagent. Anamorph: Unknown.

Other specimen examined.

USA - North Carolina • Macon Co., Coweeta Hydrological Laboratory; 27 Jun. 1998, on decorticated wood; F.A. Fernández leg.; S.M.H. 3807. • Ibid., Horse Cove Drive & Bull Pen Road, alt. 1000 m; 27 Jun. 1998; on decorticated wood; F.A. Fernández leg.; S.M.H. 3824.

Habitat and distribution.

A saprobe on decaying wood, so far known from North America in the USA (North Carolina, Tennessee) (Ellis 1887; Huhndorf and Fernández 2005).

Notes.

Huhndorf and Fernández (2005) reported P. longisporus (as Ch. ellisii ) from numerous collections from North America; the phylogenetic analysis of ITS sequences of six specimens resolved this species as a statistically unsupported clade with two strongly supported subclades. Although Huhndorf and Fernández (2005) described P. longisporus with setae scattered over the entire ascoma, in discussion, they admitted the presence of setae also around the ostiole: "In C. ellisii , C. raciborskii and C. panamensis the setae tend to be scattered over the entire surface of the ascomata, however some specimens of C. ellisii may have setae concentrated only at the apex."

Barr (1993) described the ostiole of the holotype of S. longispora surrounded by a crown of dark brown, stiff setae. We examined three collections tentatively identified as P. longisporus from North America (ILLS00121384, ILLS00121385, ILLS00121386) and in each the ostiole was delimited by densely aggregated acute setae. Apart from the ostiolar setae, additional setae were scattered over the entire ascoma, but they differed by their density among collections. The ascomata and asci of these three collections are comparable in size; the main difference lies in the ascospore length. The specimen ILLS00121384 has longer [(64.5-)68.5-86.5(-88.5) μm] ascospores compared to ILLS00121385 and ILLS00121386, which have shorter [(50.5-)52.5-68 μm] ascospores corresponding to the size given by Barr (1993) for the S. longispora holotype. In the description of P. longisporus fide Huhndorf and Fernández (2005), a wide range of ascospore lengths [(40-)50-75(-80) μm] is given, the upper limit matching the ascospore size of ILLS00121384.

In our ITS-28S phylogeny, P. longisporus fide Huhndorf and Fernández (2005) was resolved as a strongly supported clade (100/1.0/100) with two subclades. The first subclade (100/1.0/100) was introduced as a new species P. sabinianus , including ILLS00121384 (Fig. 9 ), S.M.H. 3807 ( Huhndorf and Fernández 2005: fig. 13) and S.M.H. 3824 ( Huhndorf and Fernández 2005: fig. 15) with longer ascospores, distinguished from the second subclade P. longisporus (99/1.0/100) with shorter ascospores (Fig. 8 ). The anamorph of P. sabinianus is unknown; our specimen was not isolated in axenic culture and the strains S.M.H. 3807 and S.M.H. 3824 formed only sterile mycelium in vitro ( Huhndorf and Fernández 2005).

Figures

Figure 8. Paragaeumannomyces longisporus. A, B ascomata C, D vertical section of ascomal wall E vertical section of ascomal wall and papilla with apical of setae F ascomal wall with setae G globose cells of the outer layer of the ascomal wall H, I asci J paraphyses K-N ascospores. Images: ILLS 00121385 (A, B, G); S. M. H. 3860 (C, E, M); S. M. H. 2519 (D); ILLS 00121386 (F, H-J, K); S. M. H. 2758 (L); S. M. H. 3809 (N). Scale bars: 250 μm (A-D); 50 μm (E-G); 20 μm (H-J); 10 μm (K-N).

Figure 9. Paragaeumannomyces sabinianus. A ascomata. B ascomatal setae C vertical section of ascomal wall D, E ascomal wall F, G upper part of the ascoma with ostiole surrounded by setae H setae from the ostiolar region I paraphyses J ascal apex with apical ring K asci L, M ascospores. Images: ILLS 00121384 (A, B, D, E, G-K); S. M. H. 3824 (C, F, L); S. M. H. 3807 (M). Scale bars: 500 μm (A); 20 μm (B, E, G, H); 100 μm (C, D); 25 μm (F); 5 μm (J); 10 μm (I, K-M).