Megalaria hainanensis Q. Ren, 2017

Su, Qing-Xia & Ren, Qiang, 2017, A new species of Megalaria (Ascomycota, Ramalinaceae) and M. laureri new to mainland China, Phytotaxa 313 (1), pp. 147-150 : 147-149

Megalaria hainanensis Q. Ren sp. nov. ( Figure 1 ) Fungal Name No.: FN 570453

Thallus bryophilous, composed of small verrucae. Apothecia biatorine, 1.5–2.5 (–3) mm diam. Ascus 8-spored, Biatora - type; ascospores hyaline, 1-septate, (22) –24– (25) × (9) –10 μm.

Type:— CHINA. Hainan: Mt. Wuzhi, 1600 m, 18.53°N, 109.41°E, bryophytes on siliceous rock, 16 December 2000, Man-Rong Huang 391 (Holotype, HMAS-L).

Thallus crustose, bryophilous, grey-brown, composed of small verrucae, without a distinct margin. Verrucae granular, 0.1– 0.15 mm diam. Soredia and isidia absent. Photobiont yellow green, globular, 5–7.5 μm diam. Apothecia sessile, black, biatorine, 1.5–2.5 (–3) mm diam.; disc plane to slightly concave at first, becoming slightly convex when mature; margin mostly grey-brown, persistent; proper exciple cupular with radiating hyphae, light-brown to brown-red, 50–75 μm wide; hypothecium 75–87 (–100) μm high, arnoldiana-brown, K+ intensifying red-brown to red, H+ orange-red, N+ red; hymenium 112–137 μm high, hyaline to pale brown-red, I+ blue; epihymenium cinereorufa-green, K+ intensifying greenish, H–, N+ red; paraphyses simple or sparingly branched at the tips, ca. 1 μm wide, not swollen at the apex, separating in K, ±conglutinate at the epihymenium; ascus 8-spored, cylindrical, 88–108 × 18–23 (–25) μm, Biatora - type; ascospores 1-septate, hyaline, ellipsoid, (22) –24– (25) × (9) –10 μm (n=27). Pycnidia not observed.

Chemistry: Cortex K+ yellow, C–, KC–, Pd–; medulla K+ yellow, C–, KC–, Pd–. TLC: atranorin, zeorin.

Distribution: —The type specimen was collected from National Protective Area of Wuzhishan of Hainan at an altitude of 1600 m. This area has a tropical monsoon climate with a mean annual temperature of 22.4°C, average annual precipitation of 1690 mm, an annual average relative humidity of 84% and mean annual sunshine of about 2000 hours. This species occurs on bryophytes over siliceous rock, and it is only known from the type locality.

Discussion: —Most described species of Megalaria are corticolous, although some are saxicolous or bryophilous. There are two species of the genus Megalaria occurring over mosses, i.e.: Megalaria allantoidea Fryday , described from the subantarctic Îles Kerguelen, differs from M. hainanensis by its lecideine apothecia, hyaline to pale blue-green hypothecium, the allantoid and much longer ascospores [(40–) 45 (–50) × 7–8 (–10) μm], and lack of lichen substances ( Fryday 2007); Megalaria jemtlandica (Th. Fr. & Almq.) Fryday , found in the arctic regions, such as Siberia, Sweden and Alaska., differs from M. hainanensis by its hyaline hypothecium, black apothecia, and Biatora or Lecanora - type asci tips ( Fryday 2004a). Megalaria grossa sometimes occurs on rock or bryophytes and differs from M. hainanensis by its thin thallus with totally black apothecia, a bi-layered exciple consisting of an outer prosoplectenchymatic layer and an inner layer of dense textura intricata, Lecanora - type asci tips, slightly larger ascospores (20–30 × 10–15 μm), and lack of lichen substances ( Sanderson 2009). The saxicolous species Megalaria beechingii Lendemer , described from eastern North America, closely resembles M. hainanensis in general appearance, but that species has granulose soredia on apical breakdown of areoles, black apothecial margin, blue-black epihymenium, and smaller ascospores [(12.7) –13.8– (14.8) × (4.6) –5.1– (5.4) μm] ( Lendemer 2007).

Some Megalaria species [e.g., M. albocincta (Degel.) Tønsberg , M. anaglyptica (Kremp.) Fryday & Lendemer , and M. pulverea (Borrer) Hafellner & E. Schreiner ] with atranorin and zeorin usually contain additional fumarprotocetraric acid ( Fryday & Lendemer 2010); however, fumarprotocetraric acid is not always present in the known species of this genus, e.g., M. intermiscens (Nyl.) Fryday & Lendemer and M. hainanensis , both of which are lacking fumarprotocetraric acid, whereas M. endochroma (Fée) Fryday & Lendemer contains additional pigments instead.

Figures

FIGURE 1 Megalaria hainanensis (holotype), A. Thallus with apothecium. Image showing apothecial margin concolorous with thallus; B. Section of apothecium. Image showing brown-red to dark brownish black hypothecium; C. Ascus with ascospores. Image showing 8- spored ascus with 1-septate, hyaline ascospores; D. Ascus tip Biatora-type. Scale bars: A = 1 mm; B = 50 μm; C = 10 μm; D = 20 μm.