Paragaeumannomyces albidus (T.J. Atk., A.N. Mill. & Huhndorf) 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 albidus (T.J. Atk., A.N. Mill. & Huhndorf) Reblova & A.N. Mill. comb. nov. Figure 5

Basionym.

Chaetosphaeria albida T.J. Atk., A.N. Mill. & Huhndorf, New Zealand J. Bot. 45: 688. 2007.

Specimens examined.

New Zealand - Tasman • Tasman District, Abel Tasman National Park, Pigeon Saddle point, unpaved road between Tata Beach and Totaranui ca. 10 km NW of Totaranui; 24 Feb. 2003; on decaying wood of Nothofagus sp. buried in soil; M. Réblová leg.; M.R. 2605/NZ 76 (PDD 118737). - West Coast • Westland District, Arthur’s Pass National Park, Kelly Shelter ca. 5 km W of Otira, Cockayane Nature Walk, a podocarp-broadleaf forest; 16 Mar. 2003; on decaying wood of a trunk; M. Réblová leg.; M.R. 2840/NZ 351 (PDD 118738). • Ibid.; 16 Mar. 2003; on decaying wood and bark of a branch; M. Réblová leg.; M.R. 2843/NZ 355 (PDD 118739).

Habitat and distribution.

Paragaeumannomyces albidus has been collected on Metrosideros robusta , Metrosideros sp., Nothofagus sp. and other unidentified hosts and is known from New Zealand ( Atkinson et al. 2007; this study).

Notes.

For additional illustrations and description, see Atkinson et al. (2007).

Paragaeumannomyces albidus is the only species of the genus characterised by a wide range of ascoma colours that change when ascomata are young and fresh or mature and dried. Different colours were used by Atkinson et al. (2007) to distinguish P. albidus from closely related P. bombycinus . Paragaeumannomyces albidus differs from the latter species in having distinctly papillate ascomata, which are almost white, yellowish-white, areolate and translucent when young except for the black papilla (Fig. 5A, B ). In older specimens and after drying, ascomata often become laterally pinched, dark yellow, buff, tawny to dark ginger-brown (Fig. 5C-E ). The ascomatal wall of P. albidus is thicker than that of P. bombycinus , with an outer layer containing an external melanised section. In our material, asci were longer than those in the original description, 270-295 × 18.5-20.5 μm long and 155-225 μm long in the sporiferous part vs 220-260 × 16-20 μm fide Atkinson et al. (2007). The size and septation of ascospores matched those given in the protologue, though being slightly longer in the upper range: (3-)5-11-septate, (55-)69-86 × 5-6.5(-7) μm vs (5-)7(-12)-septate, (47-)60-80 × 5-7 μm fide Atkinson et al. (2007). The ascospores exhibited a dextrinoid reaction in Melzer’s reagent turning reddish-brown except for the tips of the end cells that remain hyaline.

Attempts to isolate our specimens of P. albidus in living culture were not successful. Therefore, the DNA was extracted from herbarium material of all three collections, but only ITS1 of PDD 118738 could be amplified and sequenced. Comparison of the ITS1 sequences of our specimen and the holotype of P. albidus revealed 100 % similarity (Fig. 2 ).

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 5. Paragaeumannomyces albidus (PDD 118738). A, B young ascomata C-E mature ascomata F, G asci H paraphyses I, J sporiferous parts of the asci K, L ascospores. Scale bars: 250 μm (A-E); 10 μm (F-L).