Lobothallia semisterilis (H. Magn.) Y. Y. Zhang, 2020

Zhang, Yan-Yun, Wang, Xin-Yu, Li, Li-Juan, Printzen, Christian, Timdal, Einar, Niu, Dong-Ling, Yin, An-Cheng, Wang, Shi-Qiong & Wang, Li-Song, 2020, Squamarina (lichenised fungi) species described from China belong to at least three unrelated genera, MycoKeys 66, pp. 135-157 : 135

Lobothallia semisterilis (H. Magn.) Y. Y. Zhang comb. nov. Fig. 1A-E

Lecanora semisterilis H. Magn., Lichens from Central Asia 1: 123-124 (1940) (Basionym). ≡ Squamarina semisterilis (H. Magn.) J.C. Wei, Enumeration of Lichens in China: 232 (1991). Type: China, Gansu Province, 2450-2600 m elev., on soil, 1931, Birger Bohlin 38L (S-Holotype!).

Description.

Thallus to 5 cm across, areolate centrally, with irregularly elongate lobes at the margin, closely to loosely attached to soil; areoles angular, plane to slightly convex, continuous to crowed, ca. 1 mm across; marginal lobes ca. 1 mm wide and 2-3 mm long; upper surface white to grey, pruinose, the pruina on the marginal lobes becoming granular; lower surface white, attached to soil directly with medullary hyphae. Upper cortex colourless with pale brown upper part, 22-55 μm high; epinecral layer colourless, 10-20 μm high; algal layer ca. 95 μm high, not continuous, the interval between different groups of algae 16-32 μm wide; medulla filled with grey granules, lower cortex lacking.

Apothecia rounded, sessile, constricted at the base, up to 2 mm in diam.; disc plane to slightly convex, blackish-brown, non-pruinose; thalline margin entire, concolorous with thallus; hymenium colourless, ca. 60 μm high; subhymenium and hypothecium colourless, I + blue; epihymenium consisting of brown granules, ca. 15 μm high; paraphyses simple, slightly thickened at the apex, ca. 3 μm in diam.; asci Aspicilia -type, 8-spored; ascospores colourless, ellipsoid, 9-13 × 5-9 μm.

Pycnidia prominent, sometimes protruding from the thallus-like apothecia, with blackish-brown ostioles, numerous, 0.1-0.4 mm across; conidia bacilliform, 5.5-6.5 × ca. 1 μm.

Chemistry.

Upper cortex K + red, C-, P-, medulla K + red, C-, P + yellow; norstictic acid.

Ecology and distribution.

Growing on soil in very dry habitats at elevations of 1760-3151 m. This species was previously only known from Gansu Prov. and is reported here as new to Qinghai Prov., China.

Notes.

The holotype consists of numerous fragments on soil, without apothecia but numerous pycnidia. This species was originally described as a Lecanora by Magnusson (1940) and transferred to Squamarina by Wei (1991). We initially treated our materials as " S. semisterilis " since their morphology was identical with the holotype, which is characterised by the pruinose and lobate thallus containing norstictic acid, terricolous habit, pycnidia resembling apothecia and bacilliform conidia. We transfer this species to the genus Lobothallia , based on the phylogenetic reconstruction. Its position within this genus is supported by the lobate and slightly convex thallus, the Aspicilia -type ascus, the bacilliform conidia and the absence of usnic acid.

The genus Lobothallia is a small genus mainly growing on rocks, containing twelve species ( Kou et al. 2013; Lücking et al. 2017). We added eight of these species as intergroups to assess the phylogenetic position of Lobothallia semisterilis in the genus. The results show that Lobothallia semisterilis is close to L. alphoplaca , L. melanaspis and L. praeradiosa in the phylogeny (Fig. 2 ). However, L. alphoplaca differs in the epruinose thallus and the presence of constictic and stictic acids, L. melanaspis differs in the saxicolous habit and the distinctly rosette-forming thallus. L. praeradiosa can be distinguished by the epruinose and green grey to orange brown thallus ( Galloway and Ledingham 2012; Kou et al. 2013). Lobothallia pruinosa Kou & Q. Ren is similar to L. semisterilis in having a pruinose upper surface, but differs in the saxicolous habit and the presence of constictic acid ( Kou et al. 2013).

Figures

Figure 1. Lobothallia semisterilis (KUN-L 18 - 59656). A Habit B apothecial anatomy (LCB) C ascus and spores (Lugol's) D section of pycnidia (LCB) E section of thallus (LCB). Scale bars: 100 μm (B, E); 5 μm (C); 20 μm (D).

Figure 2. Maximum Likelihood phylogeny of the genus Lobothallia, based on nrITS. ML bootstrap value ≥ 70 % and posterior probabilities ≥ 0.95 from the Bayesian analysis are given adjacent to nodes.