Tropicoporus tamilnaduensis M. Kaliyaperumal & S. Gunaseelan, 2024

Gunaseelan, Sugantha, Kezo, Kezhocuyi, Karunarathna, Samantha C., Yang, Erfu, Zhao, Changlin, Elgorban, Abdallah M., Tibpromma, Saowaluck & Kaliyaperumal, Malarvizhi, 2024, New species of Tropicoporus (Basidiomycota, Hymenochaetales, Hymenochaetaceae) from India, with a key to Afro-Asian Tropicoporus species, MycoKeys 102, pp. 29-54 : 29

Tropicoporus tamilnaduensis M. Kaliyaperumal & S. Gunaseelan sp. nov.

Figs 9 , 10

Etymology.

The species epithet tamilnaduensis refers to the locality of the type specimen (Tamil Nadu).

Diagnosis.

Tropicoporus tamilnaduensis is characterised by applanate to meagrely ungulate basidiome with glabrous, broadly zonate, sulcate and deeply irregularly cracked pilear surface, homogenous context, obtuse margin, pores 4-5/mm, mono-dimitic hyphal system, presence of cystidioles, subglobose to broadly ellipsoid basidiospores measuring 4.5-5.7 × 3.5-4.7 μm.

Type.

India, Tamil Nadu, Cuddalore District, Thaiyalkunampattinam, Kanni Tamil Nadu ; 11°59'18"N, 79°60'17"E; 31 Dec 2022; Malarvizhi Kaliyaperumal; on a living angiosperm tree ( Madhuca longifolia ); MKDM02 (MUBL1085, holotype); GenBank: OR272297 (ITS); OR272343 (nLSU) .

Description.

Basidiome perennial, pileate, without distinctive odour or taste when fresh, woody hard and light in weight when dry. Pilei applanate to meagrely ungulate, projecting up to 5 cm, 8 cm wide and 4 cm thick at base; pileal surface glabrous, broadly zonate, sulcate, deeply irregularly cracked near attachment, brown (6E7), yellowish-brown (5F4) to golden brown (7F7) turning greyish-brown (5F3). Margin obtuse, 4 mm thick, light brown (6D5). Pore surface brown (6E6), sterile margin yellowish-brown (5E6), up to 2 mm wide; pores circular, 4-5 per mm; dissepiments thick, entire. Context homogenous, zonate, brown (6D7) to dark brown (6F8), woody hard, up to 2 cm thick. Tubes brown (6E6), up to 2 cm long, annual layers distinct, each stratum up to 0.3 cm long.

Hyphal structures.

Hyphal system monomitic in the context and dimitic in the trama, tissue darkening with KOH without hyphal swelling.

Context.

Generative hyphae, thin to thick-walled, hyaline to golden yellow, simple septate, rarely branched, 2-5 μm diam.

Trama.

Generative hyphae, dominant, thin to thick-walled, hyaline to pale yellow, septate, occasionally branched, 2-4 μm diam. Skeletal hyphae, thick-walled with narrow to wide lumen, yellowish-brown, aseptate, unbranched, 2-3.5 μm diam.

Hymenium.

Hymenial setae dark brown, thick-walled, ventricose to subulate with sharp to blunt tips, 6-19 × 3.8-5 μm. Cystidia absent. Cystidioles hyaline, thin walled, ventricose to fusoid with elongated tapering apical portion, 10-45 × 2-5 μm. Basidia clavate to broadly clavate, 7-15 × 2.7-6.2 μm, with four sterigmata and a simple septum at the base. Basidioles clavate, 5-13 × 3.5-6 μm. Basidiospores broadly ellipsoid to subglobose, pale yellow in water, turning golden yellow to brown in KOH, thick-walled, smooth, CB ̄, IKI ̄, (4.5-) 4.7-5.5 (-5.7) × (3.5-) 3.7-4.5 (-4.7) μm (n = 50/2), Q = 1.13 (Q range 1.05-1.25).

Habitat and distribution.

Basidiomes are found on living trees of Madhuca longifolia and Prosopis cineraria , distributed in Cuddalore District, Tamil Nadu, India.

Additional material examined.

India, Tamil Nadu, Cuddalore District, Thaiyalkunampattinam, Kanni Tamil Nadu ; 11°50'14"N, 79°54'14"E; 31 Dec 2022; Malarvizhi Kaliyaperumal; on a living angiosperm tree ( Prosopis cineraria ); MKDM02a (MUBL1086, Paratype); GenBank: OR272344 (nLSU) .

Notes.

Tropicoporus tamilnaduensis and T. linteus are similar in having pileate sulcate basidiomes, zonate context and a mono-dimitic hyphal system with cystidioles. However, T. tamilnaduensis differs from T. linteus in deeply-cracked basidiomes and smaller basidiospores ( Tian et al. 2013; Wu et al. 2022). Tropicoporus tamilnaduensis and T. rudis share a homogenous context, a mono-dimitic hyphal system and subglobose to broadly ellipsoid basidiospores, but T. tamilnaduensis differs in having zonate, sulcate, deeply irregularlycracked basidiome and larger pores (4-5/mm) ( Wu et al. 2022). Tropicoporus tamilnaduensis differs from T. angustisulcatus , T. lineatus and T. substratificans in having sulcate and deeply cracked basidiomes and a mono-dimitic hyphal system, while T. angustisulcatus , T. lineatus and T. substratificans have basidiomes with velutinate to glabrous, uncracked pilear surface and a dimitic hyphal system ( Zhou et al. 2015; Wu et al. 2022). Tropicoporus tamilnaduensis resembles T. excentrodendri , T. dependens and T. sideroxylicola by sharing concentrically zonate, sulcate, cracked to rimose pilear surface; however, the former differs by having a mono-dimitic hyphal system ( Zhou et al. 2015; Salvador-Montoya et al. 2018). Tropicoporus tamilnaduensis and T. guanacastensis are similar in having a mono-dimitic hyphal system; however, T. tamilnaduensis has ungulate, sulcate, deeply irregularly cracked basidiomes with larger pores (4-7/mm) and broadly ellipsoid to subglobose spores (4.5-5.7 × 3.5-4.7 μm) ( Zhou et al. 2015). Although sharing a mono-dimitic hyphal system, T. tamilnaduensis differs from T. flabellatus by having sulcate, deeply irregularly cracked basidiomes, cystidioles and larger pores (4-7/mm) with homogenous context ( Lima et al. 2022). Tropicoporus tamilnaduensis varies from T. drechsleri by having sulcate, deeply irregularly cracked basidiomes and broadly ellipsoid to ellipsoid basidiospores (4.5-5.7 × 3.5-4.7 μm) ( Salvador-Montoya et al. 2018).

Figures

Figure 9. Tropicoporus tamilnaduensis (MUBL 1085 holotype) A basidiomata (Holotype) B pore surface C cross-section of basidiome (arrows indicating stratified tube layers) D hymenial setae E-H basidiospores: E basidiospore in water F basidiospores in KOH G basidiospores in cotton blue H basidiospores in Melzer's reagent. Scale bars: 1 cm (A-C); 5 µm (D-H).

Figure 10. Tropicoporus tamilnaduensis (MUBL 1085 holotype) A tramal hyphae B contextual hyphae C hymenial setae D cystidioles E basidioles F basidia G Basidiospores. Scale bars: 5 µm.