Megasporoporia tamilnaduensis K. Kezo, M. Kaliyaperumal, S. Gunaseelan, Xue W. Wang & L.W. Zhou., sp. nov

MycoBank number: MB 559790; Index Fungorum: IF 559790; Facesoffungi number: FoF 12713 Fig. 1

Etymology: “tamilnaduensis” refers to the place of collection.

Holotype: MUBL4022

Diagnosis: Basidiomes annual, resupinate with white to brownish grey pore surface and duplex context, a dimitic hyphal system with clamped generative hyphae, presence of dendrohyphidia and tetrahedric to polyhedric crystals in the hymenium, absence of cystidia and cystidioles and cylindrical, hyaline, thin-walled basidiospores.

Basidiomes annual, resupinate, without odor or flavor when fresh, becoming corky upon drying, up to 9 cm long, 2.5 cm wide and 1.5 mm thick at the centre. Margin white (5A1) when fresh becoming yellowish white (4A2) on drying, up to 0.5 mm wide. Pore surface reddish white (7A2) when fresh to brownish grey (6C3) on drying; pores round to angular, 1–2 per mm; dissepiments thin. Context duplex without black line, yellowish white (4A2) towards substrate, white (5A1) towards the tube, up to 0.5 mm thick. Tubes concolorous with the pore surface, up to 1 mm long.

Hyphal system dimitic, skeletal hyphae dominant in context, while in trama generative hyphae. Context generative hyphae thin- to thick-walled, hyaline, clamped septate, branched, 2–3 μm in diam, CB +, IKI–; skeletal hyphae thick-walled with narrow lumen, unbranched, aseptate, 2.5–6.2 μm in diam, CB + , IKI–. Trama generative hyphae thin-walled, hyaline, clamped septate, branched, 1.8–2.5 μm in diam, CB + , IKI–; skeletal hyphae thick-walled with narrow lumen, aseptate, unbranched, 2.5–6 μm in diam, CB + , IKI–. Abundant tetrahedric to polyhedric crystals present in the hymenium. Cystidia and Cystidioles absent. Dendrohyphidia present, 1.8–2.7 μm in diam. Basidioles clavate, 14–20×7–7.8 μm. Basidia clavate, with four sterigmata, 16–24.2×7–8.2 μm. Basidiospores cylindrical, hyaline, thin-walled, smooth, IKI–, CB–, (9.5–)9.7–11.5(–12) × (3.3–)3.5–4(–4.2) μm, Q =2.85 (n=30/2).

Material examined: India, Tamil Nadu, Thiruvannamalai district, 12°29′15.4″N, 78°55′01.8″E, on dead wood, 14 November, 2019, Kezhocuyi Kezo, MUBL4022 (holotype). INDIA, Tamil Nadu, Thiruvannamalai district, Jawadhu hills, Nallapathur Reserve Forest, 12°32′49.9″N, 78°54′05.9″E, on dead wood, 14 January 2020, Kezhocuyi Kezo, KSM-NP7.

GenBank numbers: ITS=ON249127, LSU=ON254196.

Notes: Megasporoporia tamilnaduensis (MUBL4022) shares similarities with M. bannaensis (Li and Cui 2013) by annual, resupinate basidiomes and pores size (1–2 per mm). However, the former differs by the presence of dendrohyphidia and smaller basidiospore size (9.5–12×3.3–4.2 μm). The spore size of M. tamilnaduensis and M. inflate are similar; however, the latter has smaller pore size (2–3 per mm) and lacks dendrohyphidia (Wang et al. 2021b). Our Indian species shares similar pore size with M. setulosa but the latter varies by having larger basidiospore (10–14×4.2–5.7 μm) and absence of dendrohyphidia (Lira et al. 2021). Megasporoporia tamilnaduensis share similar basidiospore and pore size with M. neosetula, but the latter varies in the absence of dendrohyphidia and homogenous context (Lira et al. 2021). Megasporoporia minuta varies from M. tamilnaduensis by small pores (6–8 per mm), narrowly ovoid basidiospores, and lack of hyphal pegs, dendrohyphidia and tetrahedric or polyhedric crystals (Zhou and Dai 2008).

Figure 1 – Microscopic structures of Megasporoporia tamilnaduensis (MUBL4022, holotype). a Basidiomata. b1 Duplex Context. b2 Tube layer. c Pore surface. d Cross section of hymenium. e Crystals. f Dendrohyphidia. g Basidioles. h Basidia. i Basidiospores. j Phloxine. k Water. l Cotton blue. m Melzer. Scale bars: b-c = 1 mm, d-m = 10 μm

Figure 2 – Phylogram generated by the maximum likelihood algorithm based on combined nLSU and ITS sequence data is presented along with the bootstrap values and the Bayesian posterior probabilities above 50% and 0.8, respectively, at the nodes. Type specimens are in bold and the isolates of new species characterized are in blue