Cryptothecia sorediatum J. X. Xue & Lu L. Zhang, 2025

Xue, Junxia, Yang, Zihao, Li, Ruotong & Zhang, Lulu, 2025, Four new species of Cryptothecia (Arthoniaceae, Ascomycota) and Myriostigma (Arthoniaceae, Ascomycota) from China, based on morphology and molecular phylogeny, MycoKeys 114, pp. 367-383 : 367-383

Cryptothecia sorediatum J. X. Xue & Lu L. Zhang sp. nov.

Fig. 3

Diagnosis.

The new species differs from other species of Cryptothecia in its soralia and I – medulla.

Type.

China • Yunnan Province, Xishuangbanna Dai Nationality Autonomous Prefecture, Jinghong City, Jinuo Mountain, Jinuo Ethnic Township , 21°54'52.26"N, 101°11'33.04"E, alt. 630 m, on the bark of trees, 3 March 2023, L. L. Liu et al. 20230379 ( SDNU, holotype) .

Description.

Thallus corticolous, up to 4 cm in diameter, ecorticate, cottony, dull, pale green, firmly attached to the substrate. Soralia globose, with many calcium oxalate crystals, 0.07–0.2 × 0.07–0.2 µm. Prothallus is usually distinct, thick, whitish byssoid, mainly composed of interwoven and radiating hyphae, 0.9–1.7 mm wide. Medulla white, with calcium oxalate crystals. Photobionts trentepohlioid, cells rounded to elliptical, single or aggregate into bundles, 7–12 × 6–12 µm. Hyphae 1–2.5 µm wide.

Asci and pycnidia were not observed.

Chemistry.

thallus C + red, K –, P –, UV + pale grey-white; medulla and paraphysoids I –. TLC: gyrophoric acid and lecanoric acid.

Etymology.

The epithet refers to the presence of soralia on its thallus.

Ecology and distribution.

This species is found only in China on the bark of trees in a humid tropical forest in Yunnan Province.

Notes.

Morphologically, Cryptothecia sorediatum is similar to C. bartlettii G. Thor , as they both have C + red thallus and globose structures ( C. sorediatum has globose soralia, and C. bartlettii has globose isidia-like structures) on their thallus, but C. bartlettii has I + sky-blue medulla, 1 - spored asci and muriform ascospores ( Thor 1997).

Phylogenetically, Cryptothecia sorediatum is clustered with C. subnidulans Stirton , C. inexspectata G. Thor and C. striata G. Thor. They all have a cottony thallus and whitish byssoid prothallus, but C. subnidulans has a C – thallus, muriform ascospores (69–90 × 29–44 µm) and psoromic acid as a secondary metabolite ( Thor 1997). C. inexspectata has whitish ascigerous areas, I + sky-blue medulla and muriform ascospores (33–50 × 16–22 µm) ( Thor 1997). C. striata has granular isidia-like structures on the thallus, I + sky-blue medulla and muriform ascospores [(46 –) 55–70 (– 80) × (19 –) 23–29 (– 37) µm] ( Thor 1991).

Additional specimens examined.

China • Yunnan Province, Xishuangbanna Dai Nationality Autonomous Prefecture, Jinghong City, Jinuo Mountain , Jinuo Ethnic Township , 21°54'52.26"N, 101°11'33.04"E, alt. 630 m, on the bark of trees, 3 March 2023, L. L. Liu et al. 20230377 ( SDNU) ; • ibid., 20230381 ( SDNU) .

Figures

Figure 3. Cryptothecia sorediatum (SDNU 20230377, type) A thallus and prothallus B soralia. Scale bars: 500 µm (A, B).