Striatosphaeria castanea Reblova & J. Fourn., 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

Striatosphaeria castanea Reblova & J. Fourn. sp. nov. Figure 11

Typification.

French Guiana • Maripasoula, Saül, sentier des gros arbres, disturbed secondary rainforest; alt. 200 m; 25 Aug. 2018; on the bark of decaying woody liana on the ground associated with Xylaria papillatoides ; C. Lechat leg.; GY.J.F. 18140-1 (holotype: PRA-16328!, ex-type culture CBS 145352).

Etymology.

Castanea (Latin) chestnut-coloured, referring to the colour of conidia.

Description on the natural substrate.

Teleomorph: Ascomata perithecial, non-stromatic or formed on rudimentary basal stroma, superficial, solitary or in small groups or dense clusters, 160-200 μm diam, 170-220 μm high, subglobose to broadly conical, dark brown, glabrous, papillate. Ostiole periphysate. Ascomatal wall fragile, carbonaceous, 20-27 μm thick, two-layered. Outer layer of textura prismatica, consisting of brown, polyhedral cells with opaque walls. Inner layer of textura prismatica, consisting of several rows of thin-walled, hyaline, flattened cells. Paraphyses sparse, partially disintegrating at maturity, septate, 3-5 μm wide, tapering to ca. 2.5 μm, longer than the asci. Asci (75-)78-97(-102) × (10.5-)11-14.5 μm (mean ± SD = 87.3 ± 5.0 × 12.5 ± 1.1 µm), (56.5-)65-77(-82.5) μm (mean ± SD = 70.0 ± 4.9 µm) long in the sporiferous part, cylindrical-fusiform, stipitate, apically obtuse, ascal apex with a shallow, non-amyloid apical annulus 3.5-4.5 μm wide, 1-1.5 μm high. Ascospores (10.5-)11-13.5(-14.5) × (5.5-)6-7.5 μm (mean ± SD = 12.2 ± 0.5 × 6.7 ± 0.5 µm), ellipsoidal-fusiform, dark brown to chestnut brown, 1-septate; septum median, dark brown, with a central pore, not constricted or slightly constricted at the septum, with longitudinally arranged darker brown ridges alternating with lighter brown furrows, ascospores uniseriate or obliquely uniseriate in the ascus. Anamorph: Codinaea -like, not present on the nature substrate.

Description on CMA with sterile stems of Urtica dioica .

Colonies effuse, vegetative hyphae hyaline, branched, 2.5-3.5 μm wide. Conidiophores macronematous, mononematous, 22-66 μm long, 3.5-5 μm wide near the base, erect, straight, cylindrical, several-septate, brown, paler towards the apex, unbranched, smooth-walled, or reduced to single conidiogenous cells. Conidiogenous cells (9.5-)12.5-25(-33) × 4-4.5 μm, tapering to 2.5-3.5 μm just below the collarette, monophialidic, integrated, terminal, cylindrical to cylindrical-lageniform, pale brown, subhyaline towards the apex, smooth-walled; collarettes funnel-shaped, 4-6.5 μm wide, (1.5-)2-2.5 μm deep. Conidia (10-)11-13.5 × 4-5.5 μm (mean ± SD = 11.9 ± 0.8 × 4.8 ± 0.4 µm), reniform to ellipsoidal, straight or slightly curved, asymmetrical, narrowly rounded at the apical end, truncate at the basal end, brown, 1-septate, not constricted or slightly constricted at the septum, with 1-2.5 μm long, hyaline setulae at each end, smooth-walled, in slimy droplets, dark brown in mass.

Culture characteristics.

On CMD colonies 23-25 mm diam, circular, flat, margin entire, lanose, floccose, funiculose at the centre, cobwebby towards the periphery, whitish with irregular pale brown spots due to pigmented funiculose mycelium, with an isabelline outer zone of submerged growth; reverse beige. On MLA colonies 22-25 mm diam, circular, raised, margin entire, lanose, floccose, zonate, with grey, brown and white zones, with an isabelline outer zone of submerged growth; reverse dark grey. On OA colonies 31-33 mm diam, circular, flat, margin entire, sparsely lanose, floccose, cobwebby at the margin, zonate, whitish, colony centre with irregular dark brown spots due to pigmented submerged mycelium, pale brown towards the margin, with an olivaceous outer zone of submerged growth, dark brown pigment diffusing to agar at the colony centre; reverse olivaceous grey. On PCA colonies 17-19 mm diam, circular, slightly convex centrally, margin entire, lanose, floccose becoming cobwebby towards the periphery, isabelline to light beige with irregular brown spots due to pigmented mycelium; reverse light beige. Sporulation abundant on CMD, CMA with Urtica stems and PCA, sparse on MLA and OA.

Other specimen.

Brazil • Bahia; isolated from roots of Encyclia ghillanyi ; isolate monte6.2; GenBank (ITS): KC928368, unpublished. (Specimen not available).

Habitat and distribution.

Striatosphaeria castanea occurs on the bark of woody liana and as an endophyte of Encyclia ghillanyi . It is known from South America in Brazil and French Guiana.

Notes.

Striatosphaeria codinaeophora closely resembles S. castanea , but differs in having larger [(130-)140-160(-170) × 25-35(- 40) μm] asci, [(17-)19-23(-26) × (6-)7-9(-10) μm] ascospores and (15-20 × 4.5-6 μm) conidia ( Samuels and Müller 1978). Based on the present phylogeny (Fig. 1 ) and comparison of ITS sequences, S. castanea has also been recorded as an endophyte, isolated from roots of Encyclia ghillanyi , a rupiculous orchid inhabiting rock surfaces in semiarid areas in the Bahia state of northern Brazil (strain monte6.2, ITS: KC928368, Almeida et al. unpublished).

Figures

Figure 1. Combined phylogeny using ITS and 28 S of selected members of the Chaetosphaeriaceae. Species names given in bold are taxonomic novelties; T, ET, IST and PT indicate ex-type, ex-epitype, ex-isotype 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 11. Striatosphaeria castanea (CBS 145352). A, B ascomata C asci D ascospores E ascal apex with apical annulus F colonies on CMA with an Urtica dioica stem after 8 wk G-J conidia K-Q conidiophores R colonies on CMD, MLA, OA and PCA after 4 wk (from left to right). Scale bars: 500 μm (A, B); 20 μm (C, E); 10 μm (D, G-Q); 1 cm (F, R).