Neomensularia meridionalis Bittencourt, Alves-Silva, Góes-Neto & Drechsler-Santos, 2024, sp. nov.
Creators: name: Bittencourt, Felipe
name: Alves-Silva, Genivaldo
name: Góes-Neto, Aristóteles
name: Drechsler-Santos, Elisandro Ricardo
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Hymenochaetales
Neomensularia
Neomensularia meridionalis

description: Neomensularia meridionalis sp. nov. Bittencourt, Alves-Silva & Drechsler-Santos, Fig. 2
MycoBank: MB 852564
Etymology:—From merīdiēs (“south” or “southern”), referring to its distribution in southern South America.
Type:— BRAZIL. Rio Grande do Sul: São Francisco de Paula, on dead standing tree, 19 June 2017, G. Alves-Silva 1153 (Holotype, FLOR 77969!).
Diagnosis:—Basidiomata annual to reviving, pileate to imbricate, upper surface velvety, unaligned reviving hymenophoral layers, (5–)6–7(–8) pores/mm, context duplex with a black line, monomitic hyphal system with two types of generative hyphae, hymenial setae ventricose with hooked apex, basidiospores broadly ellipsoid to elongate, thick-walled (3.9–)4.2–5.1 × (2.6–)2.9–3.7(–4) µm.
Description:—Basidiomata annual to reviving, pileate, gregarious to imbricate, though, 12–40 mm long, 20–69 mm wide, up to 12 mm thick, when imbricate up to 52 mm long, 95 mm wide, 43 mm thick. Pileus applanate, semicircular, rarely dimidiate with a base up to 7 mm long, sometimes umbonate with a umbo up to 7 mm thick, strong brown (7.5YR 4/6), dark reddish brown (5YR 4/6) to yellowish red (5YR 4/6). Margin round to acute, slightly involute in dry basidiomata, up to 5 mm concolours with pileus surface in mature basidiomata or reddish yellow (5YR 6/8) in developing basidiomata. Pileus surface first finely velutinate to velvety, glabrous near base and older basidiomata, sometimes with a umbo with 7 mm thick, concentrically zonate and sulcate. Pores round to slightly angular, (5–)6– 7(–8)/mm, 119–221 µm wide; dissepiment thick, entire, 31–85 µm thick. Context up to 7 mm thick, duplex with a conspicuous black line with 0.3 mm thick between layers; lower layer compact, fibrous, yellowish red (5YR 5/6-8), 3–6 mm thick; upper layer spongy, loose, 0.5–1 mm thick, dark brown (7.5YR 4/6) to dark reddish brown (5YR 4/6). Tubes one or two-layered, indistinct from each other, color similar to the lower context, 1–6 mm thick. Hymenophore poroid, reddish yellow (7.5YR 6/8) to strong brown (7.5YR 5/8) in young basidiomata, becoming brown (7.5YR 4/6), strong brown (7.5YR 4/6) or dark brown (7.5YR 3/3, 3/4) in mature basidiomata; in reviving specimens a new hymenophoral layer is formed often unaligned from the older layer (Fig. 2C).
Hyphal system monomitic, hyphae simple-septate. Generative hyphae in trama and context of two types: a) hyaline to golden yellow, thin to thick-walled, wide lumen, regularly septate, regularly to sparsely branched, frequently septate 1.9–4.4(–4.8) µm diam., wall up to 1 µm; b) golden yellow, distinctly thick-walled with a wide lumen, rarely solid, parallel, rarely branched, adventitious septa present through all length, swollen in KOH with constrictions in septa, rarely with lateral ramifications of generative hyphae, resembling skeletal hyphae, (3.2–)3.4–5.2 µm diam., lumen (0.7–)0.9–2.2(–3.3) µm; in lower context narrower than in trama but otherwise similar, (1.3–)2.5–3.6 µm, lumen 1–2.1(–2.7) µm; generative hyphae in upper context golden yellow to brownish yellow, thick-walled, wide lumen, interwoven, unbranched to rarely with lateral ramifications, occasionally with adventitious septa, (3.4–)3.9–5.5 µm wide, lumen 0.9–2.6(–2.8) µm. Hymenial setae ventricose to strongly ventricose, rarely subulate, apex hooked, mono to bi-rooted, sometimes with nodules or outgrowths at base, without septa, with a root running parallel to the tube, (11–)16.9–35.6(–44) × (6.5–)7.2–10 µm. Basidia barrel-shaped, 6.5–10 × 4.5–6 µm, sterigmata up to 5 µm. Cystidioles not seen. Basidiospores broadly ellipsoid to elongate, (3.9–)4.2–5.1 × (2.6–)2.9–3.7(–4) µm, Q = 1.17–1.72, ave. = 4.6 × 3.4 µm, Qm = 1.37, with ventral portion flattened, distinctly thick-walled, golden yellow, brownish yellow to chestnut brown in KOH (xanthocroic reaction), IKI-, CB-.
Habitat and distribution:—Growing on fallen hardwood trees of unknown species. Currently known in the Atlantic Rainforest in Southern Brazil.
Additional specimens examined (paratype):— BRAZIL. Santa Catarina: Rodeio, Morro do Eremitério Beato Egídio de Assis, on fallen tree trunk, 3 November 2021, G. Alves-Silva, F. Bittencourt, L.A. Funez 1376 (FLOR 77970!).
Comments:— Neomensularia meridionalis can be recognized macroscopically by its imbricate basidiomata with a velvety surface, umbonate pileus with a velvety upper surface, unaligned reviving hymenophoral layer, small size of pores [(5–)6–7(–8) pores/mm] and a duplex context with a conspicuous black line. Microscopically it can be characterized by the skeletal hyphae of unlimited growth, ventricose hymenial setae with hooked apex and golden yellow basidiospores measuring (3.9–)4.2–5.1 × (2.6–)2.9–3.7(–4) µm.
Neomensularia crocitincta is morphologically and phylogenetically close to N. meridionalis (Fig. 1), sharing the pileate habit, hyphal system, similar number of pores per mm, and size of basidiospores (Ryvarden 2005, Wu et al. 2016). Neomensularia crocitincta can be distinguished by its smaller basidiomata (up to 20 mm long), a glabrous pileus surface with a crust, a homogeneous context, and hyaline to pale yellow basidiospores, whereas N. meridionalis has larger basidiomata (up to 40 × 69 mm), a velvety pileus surface without crust, a duplex context with a black line, and golden yellow basidiospores (Ryvarden 2005, Wu et al. 2016). Additionally, Neomensularia crocitincta occurs in Costa Rica, Cuba, Jamaica, and Venezuela, and is possibly widespread in the Caribbean region (Ryvarden 2005, Wu et al. 2016). A specimen collected by J. Rick in Rio Grande do Sul state, Southern Brazil, and determined by C. G. Lloyd as Polyporus crocitinctus Berk. & M.A. Curtis is currently held at BPI (BPI 302647). However, we could not study this specimen nor find any literature published by either C. G. Lloyd or J. Rick mentioning this record, and we were unable to confirm the occurrence of N. crocitincta in Brazil.
Another species of Neomensularia found in the Americas is N. arizonica, which occurs in Mexico and the USA (Gilbertson 1969, Valenzuela et al. 2013). It can be distinguished from N. meridionalis by its larger pores (3–5/mm compared to 6–7/mm in N. meridionalis) and lacerated dissepiments (entire in N. meridionalis) (Gilbertson 1969).
description: Published as part of Bittencourt, Felipe, Alves-Silva, Genivaldo, Góes-Neto, Aristóteles & Drechsler-Santos, Elisandro Ricardo, 2024, Neomensularia meridionalis sp. nov. (Hymenochaetales, Basidiomycota), a New Species from South America, pp. 67-76 in Phytotaxa 659 (1) on pages 71-73, DOI: 10.11646/phytotaxa.659.1.5, http://zenodo.org/record/13217788