Lobothallia pseudopruinosa Lun Wang & Y. Y. Zhang, 2025

Wang, Lun, Feng, Yi-Shan, Wang, Li-Song, Wang, Xin-Yu & Zhang, Yan-Yun, 2025, An overview of the genus Lobothallia (lichenized Ascomycota, Megasporaceae) in China, MycoKeys 125, pp. 205-244 : 205-244

Lobothallia pseudopruinosa Lun Wang & Y. Y. Zhang sp. nov.

Fig. 5

Etymology.

The epithet indicates that this species is similar to Lobothallia pruinosa in morphology.

Diagnosis.

This species is characterized by its tightly adnate and thin thallus, areolate center and shortly lobate margin; plane, white or brownish gray upper surface with fine granular pruina; cryptolecanorine apothecia; large ascospores (10.0 -) 11.8–13.3 – 14.8 (- 17.0) × (8.0 -) 8.5–9.3 – 10.0 (- 11.0) µm; and its long conidia (5 –) 6–8 (– 9) × 1 µm.

Holotype.

China • Xizang Autonomous Region: Shigatse Ci., Dingri Co., Zhaguo Vil. , 28°35'23.26"N, 86°53'55.21"E, alt. 4320 m, on rock, 27 July 2019, Li-Song Wang et al. 19-64075 ( KUN-L 68571 ) .

Description.

Thallus tightly adnate to the substrate, up to 3 cm across, centrally areolate, 1–2 mm thick, marginally lobate, 0.3–0.8 mm thick. Areoles (0.3 –) 0.6–1 (– 1.5) mm wide, angular to rounded, flat, not constricted at base; interspaces between areoles 0.05–0.1 mm wide. Lobes radiate, short, plane, apices equal to slightly wider than base, 1–2 mm long, base 0.5–1 mm wide, apex 0.5–1.5 mm wide. Upper surface white or pale brownish gray, pruinose, brownish where pruina thin. Upper cortex paraplectenchymatous, 30–50 µm thick, containing dark brown granules (soluble in K); epinecral layer with dense grayish-black granules (insoluble in K), 10–40 (– 50) µm thick. Algal layer 70–100 (– 150) µm thick, discontinuous; photobiont chlorococcoid, (6 –) 8–20 µm diameter. Medulla 0.1–0.5 mm thick, opaque, filled with grayish-black granules (insoluble or partially soluble in K). Lower cortex absent.

Apothecia cryptolecanorine, common, grouped in the center, 1–3 per areole, angular, (0.1 –) 0.3–0.8 (– 1.0) mm in diameter; disc concave, brownish to black, matt, pruinose; apothecial margin indistinct, concolorous with the thallus. Exciple narrow, widening to 10–30 (– 50) μm in the uppermost part. Epithecium, hymenium and subhymenial layers combined (100 –) 125–150 (– 175) µm high; epithecium 5–15 µm thick, gelatinous; epihymenium 15–25 µm high, with dark brown to brownish granules (soluble in K), N –; hymenium (70 –) 90–100 (– 110) µm high, hyaline, I + blue; subhymenial layers 50–75 µm high, hyaline, I + blue; algal layer relatively continuous below hypothecium, 50–70 μm high; paraphyses submoniliform, simple, septate, with 1–3 uppermost cells shorter and wider than the basal cells, 4–6 μm wide (basal cells ca. 2 μm wide); asci clavate, Aspicilia - type, hyaline, 8 - spored, 60–75 × 15–25 µm; ascospores simple, hyaline, broadly ellipsoid, rarely spherical, (10.0 -) 11.8–13.3 – 14.8 (- 17.0) × (8.0 -) 8.5–9.3 – 10.0 (- 11.0) µm (n = 86), l / w ratio (1.0 -) 1.2–1.4 – 1.6 (- 2.1), wall ca. 1 µm thick. Pycnidia rare, punctiform, slightly convex, 0.05–0.1 mm diameter, ostiole brown to dark brown, conidia bacilliform, hyaline, (5 –) 6–8 (– 9) × 1 µm.

Chemistry.

Cortex K + pale yellow or orange, P –. Medulla K + yellow to orange-red, P + yellow, C –, KC –. Containing norstictic and connorstictic acids.

Habitat and distribution.

Saxicolous. Currently known only in Qinghai, Xizang Province, China.

Notes.

Specimens of this new species were collected from Qinghai and Xizang Provinces, China, at elevations ranging from 3000 to 4500 m. The overall morphology of these specimens is uniform, with the exception of voucher 20-67831 ( KUN-L 76010 ), which exhibits a thinner upper cortex composed of loosely arranged hyphae.

Phylogenetically, Lobothallia pruinosa and L. densipruinosa are the closest relatives of the new species. L. pruinosa can be distinguished by its lecanorine apothecia at maturity and broader lobes. L. densipruinosa differs in its whitish to light greenish gray and entirely pruinose thallus, apothecial disc dark olivaceous when wet and blackish when dry, and the absence of connorstictic acid ( Kou et al. 2013; Ashraf et al. 2022). Lobothallia pakistanica resembles L. pseudopruinosa in its white, lobate thallus but differs in possessing larger central areoles, broader marginal lobes, and lacking of secondary metabolites ( Zulfiqar et al. 2022).

Within Lobothallia , L. brachyloba , L. platycarpa L. pulvinata and this new species share an areolate thallus with lobate margins, a whitish to whitish-gray upper surface, and the presence of norstictic acid. Nevertheless, each can be distinguished by specific characters: L. brachyloba has sparse thalline and 1–7 apothecia per areole ( Paukov et al. 2019); L. platycarpa possesses larger areoles, fewer and non-aggregated apothecia, and limited distribution in North Africa ( Algeria) ( Zulfiqar et al. 2022); And L. pulvinata exhibits a thinner thallus and upper cortex (10–15 µm), and lecanorine apothecia ( Zulfiqar et al. 2023). Additionally, Lobothallia cheresina , L. controversa , and L. lacteola also have a tightly adnate, whitish to whitish – gray thallus, but these species differ from L. pseudopruinosa in their absent or indistinct marginal lobes and their different secondary metabolites.

Additional specimens examined.

Lobothallia pseudopruinosa . China • Xizang: Shigatse Ci., Dingri Co., Zhaguo Vil. , G 219, 28°35'09.99"N, 87°03'42.35"E, alt. 4306 m, on surface of weathered shale in open area, 16 June 2022, Li-Song Wang et al. 22-71222 ( KUN-L 85846 ), Yan-Yun Zhang ZYY 22-324 ( KUN-L 81905 ), ZYY 22-326 ( KUN-L 81907 ) • Angren Co., 29°19'01.32"N, 87°01'59.60"E, alt. 4524 m, on rock, 19 July 2019, Li-Song Wang et al. 19-63621 ( KUN-L 68115 ) • Qinghai Prov.: Yushu Tibetan Autonomous Prefecture, Qumalai Co., Qumahe Vil. , 34°54'50.67"N, 94°46'20.74"E, alt. 4396 m, on limestone, 17 September 2020, Li-Song Wang et al. 20-68331 ( KUN-L 76512 ) • Zeku Co., Maixiu Town , 35°15'53.57"N, 101°52'30.23"E, alt. 3143–3163 m, on rock, 8 July 2022, Xin-Yu Wang and Min Ai XY 22-1089 ( KUN-L 84907 ), XY 22-1088 ( KUN-L 84906 ), An-Cheng Yin and Han-Xiang Chen 22-72438 ( KUN-L 87064 ) • Jiuzhi Co., NianBaoYuZe National Geopark , 33°13'57.57"N, 100°55'58.56"E, alt. 4063 m, on sandy soil, 8 September 2020, Li-Song Wang et al. 20-67831 ( KUN-L 76010 ) .

Lobothallia pruinosa . China • Nei Mongol: Bayanhot Town, Helan Mountain , alt. 1600 m, on rock, 17 August 2011, H. Y. Wang 20123575, 20123154, 20123282, 20123626 ( SDNU) • Urat Rear Banner Co., alt. 1600 m, on rock, 19 August 2011, H. Y. Wang 20122917 ( SDNU), D. B. Tong 20123276, 20123888 ( SDNU) • Qinghai Prov.: Hualong Hui Ehtnic Autonomous Co., Yashiga Town , 36°03'52.78"N, 101°57'03.44"E, alt. 2002 m, on rock, 8 July 2022, Li-Song Wang et al. 22-73170 ( KUN-L 87648 ).

Figures

Figure 5. Lobothallia pseudopruinosa (KUN-L 68571, holotype). A. Thallus; B. Areoles and apothecia; C. Lobes; D. Section of thallus; E. Section of thallus (LCB); F. Vertical section of apothecium; G. Vertical section of apothecium (Lugol’s solution); H. Vertical section of apothecium (LCB); I. Ascus and ascospores; J. Paraphyses (LCB); K. Conidia. Scale bars: 1 mm (A); 0.2 mm (B, C); 50 µm (D, F); 20 µm (E, G, H); 5 µm (I, J, K).