Sanghuangporus subzonatus S. Gunaseelan, M. Kaliyaperumal & K. Kezo sp. nov.

Index Fungorum number; IF 902414; Mycobank number: MB 902414; Facesoffungi number: FOF13990. Fig. 1

Etymology – The species epithet “subzonatus”, signifies the close phylogenetic relationship with the species Sanghuangporus zonatus

Holotype – MUBL4023

Basidiomata perennial, solitary, pileate, sessile, without odor or taste, hard corky to woody hard when fresh, become woody hard when dry. Pileus dimidiate, applanate, with no distinct crust, projecting up to 3.5 cm to 6.3 cm, 6.7 cm wide and 4.7 cm thick near attachment. Pileal surface brown (6F4), yellowish brown (5E7, 5E8) to dark brown (6F8) when young, infrequently tuberculae, concentrically zonate, on maturation pilei becoming brownish grey (5F2), narrowly sulcate with few cracks near attachment. Margin distinct, sterile, obtuse, yellowish brown (5D6) to golden brown (5D7). Pore surface yellowish brown (5D6) to golden brown (5D7); Pores round to angular, 6–9/mm; Dissepiments entire, thin. Context homogenous, up to 2.7 cm thick, yellowish brown (5D8) to brown (6D7). Tube layer golden brown (5D7), stratified, tubes upto 0.2 cm long.

Hyphal system monomitic in the context and dimitic in trama; generative hyphae simple septate; tissue darkening in KOH without hyphal swelling; Context Generative hyphae, thin to thick walled, hyaline to golden brown, simple septate, occasionally branched, 2–5.2 μm diam., Trama Generative hyphae, dominant, thin to thick-walled, hyaline to yellowish, septate, occasionally branched, 2–5 μm dia.; Skeletal hyphae, thick walled with a distinct narrow to wide lumen, yellow to yellowish brown, aseptate, unbranched, 2–5 μm dia. Hymenial setae thick-walled, dark brown, ventricose to subulate, with a sharp or obtuse tip, occasionally with lateral appendages, 11.2–39×3–10 μm. Cystidioles hyaline, thin-walled, ventricose to fusoid with elongated tapering apical portion, or abruptly narrow apices, 5–27.5×3–6 μm.  Basidia clavate to sub clavate, 5.5–11 × 4–5.5 μm, with four sterigmata and a simple septum at the base. Basidioles clavate, 4–11.5×3.5–5.2 μm. Basidiospores smooth, broadly ellipsoid to subglobose, juvenile spores thin to fairly thickwalled, hyaline to yellowish, CB+, IKI ̄.; matured spores slightly thick walled to thick walled, pale yellow to golden yellow in water, turning golden yellow to brown in KOH, CB ̄, IKI ̄, (3.9–) 4.5–4.8 (–4.9) ×(3–) 3.2–3.6 (–3.8) μm (n=50/2), Q =1.35 (Q range 1.02–1.5). Chlamydospores, smooth, irregular, globose to subglobose, golden brown in water, turning to rust brown in KOH, 5.5–9×5–7.5 μm, CB(+) to CB ̄, IKI ̄.

Material examined – India, Tamil Nadu, Salem District, Kolli Hills, 11° 17′ 42.60″ N 78° 23′ 07.45″ E, on dead wood, 03 February 2018, Sugantha Gunaseelan (MUBL4023, holotype).

Additional Material examined – India, Tamil Nadu, Salem District, Kolli Hills, 11° 17′ 43.61″ N 78° 25′ 08.52″ E, on dead wood, 03 February 2018, Malarvizhi Kaliyaperumal (MSK-II-AS04, Paratype).

GenBank numbers – ITS: OP363954; LSU: OP379563 (MUBL4023, holotype); ITS: OQ225689; LSU: OQ225691 (MSK-II-AS04, Paratype).

Notes – Morpho-microscopical analyses and phylogenetic studies of the combined ITS and LSU dataset show that S. subzonatus fits well within the Sanghuangporus genus concept (Fig. 142) (Zhou et al. 2015). Sanghuangporus zonatus and S. subzonatus share similar morpho-microscopical characteristic features such as concentrically zonate pileal surface, basidiomes more or less cracked with age, monodimitic hyphal system. However, S. subzonatus significantly varies from S. zonatus, by having obtuse margin, presence of cystidioles and larger basidiospores (3.9–4.9×3–3.8 μm) (Tian et al. 2013). The present phylogenetic study indicated that S. subzonatus is closely related to S. zonatus with significant support (98% ML, 1.00 Bayesian posterior probability (BYPP)). Sanghuangporus vitexicola formed a wellresolved sister clade to S. subzonatus (98% ML, 1.00 BYPP), the former has dimitic hyphal system with radially rimose and cracked basidiome, acute margin whereas S. subzonatus is having mono-dimitic hyphal system with few cracks in near attachment (Wu et al. 2020).

Figure 1 – Sanghuangporus subzonatus (MUBL4023, holotype) Morphological characteristics of Sanghuangporus subzonatus a Basidiomata (holotype). b Pore surface. c Cross-section of basidiome showing obtuse margin. d Stratified tube layer. e hyphae from context. f Tramal hyphae. g Cystidioles. h Hymenia setae. i Basidia. j Basidioles. k–o Basidiospores: k Basidiospore. l Basidiopore in water. m Basidiopore in KOH. n Basidiopore in cotton blue. o Basidiopore in Melzer’s reagent. Scale bar: e–o=5 μm

Figure 2 – phylogram generated from Bayesian analysis based on combined ITS and LSU rDNA sequence data of Sanghuangporus spp. The combined analyses include 29 taxa, which comprised 1908 characters (LSU: 933, ITS: 966) after alignment. The new species sequences used in the study are in bold. The tree is rooted with Inocutis tamaricis (CBS 384.72) and Inonotus compositus (Wang 552). Bootstrap support values for Maximum Likelihood (ML)≥65% and Bayesian posterior probability (BYPP)≥0.95 are given above the nodes. Type species are bold and newly generated taxa in green