Squamarina kansuensis (H. Magn.) Poelt

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

Squamarina kansuensis (H. Magn.) Poelt Fig. 5C-G

Lecanora kansuensis H. Magn., Lichens from Central Asia 1: 116-117 (1940). Type: China, Gansu Province, 1500-1700 m elev., on soil, 1930, Birger Bohlin 202 (S-Holotype!) (Basionym)

Description.

Thallus terricolous, loosely to tightly adnate on soil, irregular to radiate in outline and with elongate marginal lobes, up to 10 cm in diam.; lobes 2-4(5) mm long, 1-2(3) mm wide, 0.2-0.4 mm thick, with white, thickened and slightly upturned edges, more or less overlapping; upper surface greenish to straw, pruinose and strongly cracked at least in the centre of the thallus; lower surface well delimited, milk-white to pale, without rhizines, margins usually containing sparse white tomentum. Upper cortex filled with yellowish-brown granules, turning colourless in KOH, 26-32 μm thick; epinecral layer grey to brown, 5-15 μm thick; algal layer continuous, well delimited, ca. 50 μm high; medulla grey, filled with calcium oxalate crystals; lower cortex lacking.

Apothecia frequent, rounded, single or in small groups, usually less than 2 mm in diam. Disc pale brown to reddish-brown, slightly concave to flat when young, usually becoming strongly convex with age. Thalline margin distinctive when young and disappearing with age. Hymenium colourless, I + blue, ca. 65 μm high; epihymenium yellowish-brown turning colourless in KOH, ca. 12.5 μm high; thalline margin with evenly thick cortex filled with grey granules; paraphyses septate, ca. 2.5 μm in diam.; hypothecium colourless, 75-87 μm high; algal layer below hypothecium continuous, 62-87 μm high; ascus Porpidia -type, 8-spored; ascospores colourless, ellipsoid to slightly fusiform, variable in size and shape even within one ascus, 7.5-15 × 5-7.5 μm.

Chemistry.

Upper cortex K-, C-, P-, medulla K-, C-, P+ yellow; isousnic, usnic, psoromic and 2'-O-demethylpsoromic acids.

Ecology and distribution.

Growing on soil at 1310-4730 m of elevation. Previously only known from Gansu Prov. and reported here as new to Neimenggu, Ningxia, Sichuan, Xizang, Xinjiang and Yunnan provinces, China.

Notes.

The holotype consists of several small fragments on soil, bearing a single small apothecium. This species was originally described as a Lecanora by Magnusson (1940) and transferred to Squamarina by Poelt (1958). It is characterised by the pruinose, greenish- to straw-coloured thallus, lobes with white, thickened and slightly upturned edges, exposing a milk-white to pale lower surface, without rhizines and the presence of psoromic and 2'-O-demethypsoromic acids. This species is very common in the deserts and alpine zones of China. In desert regions, the thallus is usually irregular in outline with wider lobes and becomes rosette-like with narrower lobes when growing in the alpine zone.

The genus Squamarina (= S. sect. Squamarina ) includes eleven species ( Poelt 1958) and there are three species with sequences in GenBank. We integrated the data from GenBank with the newly-produced data here to reconstruct the phylogeny of the genus Squamarina to assess the phylogenetic position of the species S. kansuensis (Fig. 6 ). The results show that S. kansuensis is a sister species to S. lentigera which, in turn, is also very similar in morphology, but differs in the larger thallus and by containing psoromic and 2'-O-demethypsoromic acids. Squamarina nivalis Frey & Poelt and S. provincialis Clauzade & Poelt are similar to S. kansuensis in having a strongly white pruinose thallus; however, S. nivalis differs in the smaller thallus, ca. 2 cm, not cracked upper surface, the apices of lobes bent downwards and the absence of psoromic acid; S. provincialis differs in the continuous but never overlapped lobes, the absence of the white thickened edges of lobes and the presence of atranorin. So far, the two species, S. nivalis and S. provincialis , are only known from very restricted places from Europe.

Specimens examined (all in KUN-L unless otherwise noted).

China: Gansu Province: Jiayuguan, 1500 m-1700 m elev., 1930, Briger Bohlin, S-L60805 (S); Yumen Ci., Moshan National Geological Park, 1760 m elev., 39°57'N, 97°14'E, on soil, 2018, Li-Song Wang et al. 18-59601; Sunan Co., Binggou Danxia landform Park, 1970 m elev., 38°56'N, 99°50'E, on soil, 2018, Li-Song Wang et al. 18-59658; Ningxia Province: Mt. Helanshan, 38°40'N, 1310 m elev., 105°46'E, on soil, 2014,Dong-Ling Niuet al. 14-09-1429 (NXAC); Qinghai Province: Wulan Co., Gobi desert along the way from Chaka to Wulan, 3151 m elev., 36°52'N, 98°55'E, on soil, 2018, Li-Song Wang et al. 18-59260, along the way from Wulan to Delingha, 3039 m elev., 36°59'N, 98°12'E, on soil, 2018, Li-Song Wang et al. 18-59274, 18-59306; Delingha Ci., Chayegou Station, 2974 m elev., 37°23'N, 96°37'E, on soil, 2018, Li-Song Wang et al. 18-59344, 18-59343. Sichuan Province: Derong Co., 1960 m elev., 28°12'N, 99°20'E, on soil, 2009, Li-Song Wang & Wang Jue 09-31112, 09-31118; Xizang Province: Linzhou Co., 3780 m elev., 29°54'N, 91°14'E, on soil, 2016, Li-Song Wang et al. 16-54052; Xinjiang Province: A-ke-tao Co., Oytagh observation zone, 2850 m elev., 38°54'N, 75°14'E, on soil, 2013, Hurnisa Shahidin et al. 20139103; Yunnan Province: Deqin Co., 2110 m elev., 28°13'N, 99°19'E, on soil, 2012, Li-Song Wang et al. 12-34756. Neimenggu Province: Beli-miao, 41°30'N, 110°10'E, on soil, 1929, Briger Bohlin, S-F304837 (S).

Figures

Figure 5. Lecanora chondroderma (A, B KUN-L 18 - 60317): A habit B apothecial anatomy (LCB) and ascospores (water). Squamarina kansuensis (C-G KUN-L 18 - 59601): C habit D apothecial anatomy (LCB) E ascus and ascospores (LCB) F apical structure of ascus (Lugol's) G section of thallus (LCB). S. oleosa (H, I KUN-L 09 - 30043): H habit I ascus and ascospores (water). Scale bars: 100 μm (B - apothecia, D); 5 μm (B - ascospores, F); 10 μm (E); 20 μm (G); 25 μm (I).

Figure 6. Maximum Likelihood phylogeny of the genus Squamarina and related genera, based on nrLSU. ML bootstrap value ≥ 70 % and posterior probabilities ≥ 0.95 from the Bayesian analysis are given adjacent to nodes.