Cyphellostereum indicum S. Nayaka and A. Debnath, 2023

Nayaka, Sanjeeva & Debnath, Ambikesh, 2023, Cyphellostereum indicum (Hygrophoraceae), a new species of basidiolichen from India, Phytotaxa 603 (3), pp. 271-279 : 272-276

Cyphellostereum indicum S. Nayaka and A. Debnath sp. nov. Figs. 1 , 2 .

MycoBank MB 849435

GenBank accession number: OQ544589

Diagnosis:—Differing from other species of Cyphellostereum with distinct stipulate, flattened, flabelliform hymenophores, irregular to pip-shaped basidiospores and loose mycobiont hyphae encircling the cyanobacterial filaments.

Type:— INDIA. Arunachal Pradesh: East Kameng district, Bameng, near Kasturba Gandhi Balika Vidyalaya School , (N 27°32’38.95”, E 92°57’19.00”), on soil, elev. 1301 m, 09-11-2022, S. Nayaka and A. Debnath 22-047553 (LWG-holotype) .

Description:— Thallus terricolous, on wet soil, crustose, olive green to brownish, filamentous, interwoven with algal mat, undifferentiated, homomerous; hyphae dense at the base of hymenophores, cottony, loose, irregular, simple, hyaline, thin, 2.2–2.9 μm; photobiont cyanobacteria, Rhizonema , filamentous, unbranched, cells thin, in chains, square to cylindrical, 6–8 μm long and 5.1–6.9 μm wide, heterocysts intercalary, pale yellow, 7–8 μm long, 5–6 μm wide; fungal hyphae of mycobiont loosely wrapped around photobiont filaments, encircling the filaments at several points, lacking haustoria, clamp connections lacking or not seen.

Hymenophores (basidiomata) stipulate, arising from the primary thallus, solitary, stipe narrow, expanding upwards, thin, dorsiventrally flattened, flabelliform, smooth, white to cream-coloured, 1.87–3.77 × 1–3.66 mm; hyphae thick, compactly intertwined; holobasidia scattered 16.7–20.11 × 2.5–5.5 μm, lacking a basal clamp; basidia clavate, bearing four prominent sterigmata; sterigmata thin, slender, 3.5–4.2 × 0.8–1.1 μm; basidiospore s with hilar appendage, simple, asymmetric, thin-walled, smooth, irregular to pip-shaped (tear drop), 3.18–4.9 × 2.06–2.9 μm, inamyloid; basidioles numerous, palisade, clavate 10–15 × 1.5–3.8 μm, lacking hymenial cystidial elements.

Chemistry:—Thallus and hymenophore K-, C-, KC-, P-, UV-; no substances detected by TLC.

Distribution and ecology:— Cyphellostereum indicum is currently recorded only in East Kameng district of Arunachal Pradesh. It was found growing on a wet, vertical surface of a mound of soil on a roadside at an elevation of 1300 m.

Etymology:—The species epithet refers to its type locality country, ‘India’.

Phylogenetic analysis:—The phylogenetic analyses confirmed that Cyphellostereum indicum belongs to the Cyphellostereum clade and is unambiguously distinct from other taxa. The sequence of Cyphellostereum indicum formed a well-supported (BS>75 %) separate clade outside a group comprising C. ushimanum H. Masumoto & Y. Degawa (2022: 177) , C. unoquinoum Dal-Forno, Bungartz & Lücking (2017: 59) , and C. phyllogenum (Müll. Arg.) Lücking, Dal-Forno & Lawrey (2013: 24) signifying its position as an autonomous, independent and well-supported monophyletic lineage ( Fig. 3 ).

Figures

FIGURE 1. Morphological features of the hymenophore of Cyphellostereum indicum (Holotype). A. Flabellate basidiome (black arrow) radiating out of the lichenized thallus (white arrow), B. Ventral view of the mature basidiome, C. Dorsal view of the mature basidiome. Scale bars A = 1mm; B = 0.5mm; C = 1mm.

FIGURE 2. Microscopical features of the of Cyphellostereum indicum (Holotype). A. Mycobiont hyphae surrounding the photobiont Rhizonema (black arrow), B. Basidium with sterigmata and basidiospore. C–D. Basidiospores. Scale bars: A–B= 5µm; C–D = 3µm.

FIGURE 3. Molecular phylogenetic analysis of Cyphellostereum by the Maximum Likelihood method, only values ≥ 50% are shown in the tree. The scale bar signifies the nucleotide substitutions per sites.