Oxneriaria deosaiensis Khalid & Usman

Usman, Muhammad, Dyer, Paul S., Brock, Matthias, Wade, Christopher M. & Khalid, Abdul Nasir, 2024, Two novel species of arctic-alpine lichen-forming fungi (Ascomycota, Megasporaceae) from the Deosai Plains, Pakistan, MycoKeys 102, pp. 285-299 : 285

Oxneriaria deosaiensis Khalid & Usman

Fig. 2

Etymology.

The specific epithet " deosaiensis " refers to the Deosai Plains, the type locality.

Holotype.

Pakistan. Gilgit Baltistan: Deosai Plains (35°0'10.06"N, 75°15'0.45"E, elev. 4,689 m) on soil, 13 May 2019, M. Usman DEO206 (LAH, holotype; LAH37200). GenBank OR037225 [ITS], OR037221 [LSU], OR037261 [mtSSU].

Diagnosis.

It differs from its closest species O. pruinosa by having lobate black margins (vs. non-lobate), K test positive light brown (vs. K positive yellow), KC test positive dark brown (vs. KC negative), apothecia epruinose (vs. densely pruinose), distinct proper-exciple 30-50 µm wide (vs. indistinct) and polarilocular ellipsoid ascospores (vs. simple ellipsoid).

Description.

Thallus crustose, epilithic, irregular, 1.5-2 cm across, zonate, areolate to poorly bullate up to 0.8 mm in diam. to lobate up to 1.5 mm at margins, determinate and radiate. Hypothallus light grey. Upper surface dull grey, black at margins. Thallus heteromerous, upper cortex 20-55 µm thick, paraplectenchymatous hyaline cells 6-15 µm in diam. Algal layer discontinuous, 50-90 µm thick, photobiont Trebouxia sp, coccoid cells, globose to sub-globose, 13-21 µm in diam. Medulla and lower cortex not differentiated and consisting of paraplectenchymatous, globose to sub-globose hyaline cells, 5-12 µm diam.

Apothecia without stipe, aspicilioid, epruinose, one apothecium per areole, rounded, 520-700 µm in diam., with black disc 350-550 µm in diam., dull, concave. Proper exciple, 30-50 µm thick. Thalline exciple 90-145 µm thick. Epihymenium brown, 10-24 µm thick. Hymenium hyaline, 90-160 µm thick. Hypothecium hyaline, 50-90 µm thick. Asci clavate, 8-spored, 75-110 × 16-27 µm. Ascospores hyaline, ellipsoid, polarilocular 11-18 × 7-10 µm. Paraphyses moniliform, septate, cylindrical cells 4-10 × 1-2 µm, with internally brown terminal cells. Pycnidia roccella type ( Ryan et al. 2002), globose to pyriform, 230-320 × 210-280 µm dark brown ostiole, long filiform hyaline conidia, 19-35 × 1 µm.

Ecology.

Saxicolous, Quartz, known only from Deosai Plains, Gilgit-Baltistan, occurring at elevations between 4,364 m and 4,689 m in extreme cold conditions.

Chemical study.

K +ve (light brown), C -ve, KC +ve (dark brown), UV +ve (light green), hymenium initially blue then turning dark blue after Lugol’s solution. Substictic acid and two unknown substances detected through TLC.

Additional material examined.

Pakistan. GILGIT BALTISTAN: Deosai Plains , 35°6'28.58"N, 75°44'27.37"E, 4,364 m, on rocks, 15 May 2019, M. Usman & Kamran Habib DEO666 (LAH, paratype; LAH37416; GenBank OR 037226 [ITS], OR037222 [LSU], OR037262 [mtSSU].

Figures

Figure 2. Oxneriaria deosaiensis sp. nov. holotype (LAH 37200) A thallus B margins C apothecia under stereomicroscope D ascospores in Lugol's solution E conidia F pycnidium. Photos by Muhammad Usman. Scale bars: 1 cm (A); 1 mm (B, C); 20 μm (D); 30 μm (E); 100 μm (F).