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

Fig. 2

Diagnosis.

The new species is distinguished from other Cryptothecia species by its verrucose pseudisidia, which are loosely scattered on the thallus. The upper parts of the pseudisidia are white or have darker dots.

Type.

China • Hainan Province, Baoting Li and Miao Autonomous County, Qixianling Hot Spring National Forest Park , 18°42'14.43"N, 109°41'47.92"E, alt. 325 m, on the bark of trees, 8 March 2023, J. X. Xue et al. 20230146 ( SDNU, holotype) .

Description.

Thallus corticolous, up to 15 cm in diameter, ecorticate, cottony, dull, pale green, loosely attached to the substrate. Pseudisidia verrucose, loosely scattered on the thallus, upper parts white or with darker dots, and most pseudisidia have few projecting hyphae, 0.13–0.26 × 0.13–0.22 mm. Prothallus is usually distinct, thin, whitish byssoid, mainly composed of interwoven and radiating hyphae, 1.1–1.5 mm wide. Medulla white, with calcium oxalate crystals. Photobionts trentepohlioid, cells elliptical to oblong, single or aggregate into bundles, 10–23 × 7–18 µm. Hyphae 1–2.5 µm wide.

Asci and pycnidia were not observed.

Chemistry.

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

Etymology.

The epithet refers to its pseudisidia, which are verrucose and loosely distributed across the thallus.

Ecology and distribution.

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

Notes.

Morphologically, Cryptothecia disjecta is similar to both Herpothallon and Cryptothecia . However, we describe C. disjecta on the basis of its morphological and chemical characteristics and assign it to Cryptothecia on the basis of sequencing ( Aptroot et al. 2024). Cryptothecia disjecta is similar to C. eungellae G. Thor , as they both have whitish byssoid prothallus, I + sky-blue medulla and C + red thallus, but C. eungellae has 1 - spored asci, muriform ascospores, and gyrophoric acid and norstictic acid as secondary metabolites ( Thor 1997; Jagadeesh Ram and Sinha 2016).

Phylogenetically, Cryptothecia disjecta is clustered with C. bartlettii G. Thor. They both have cottony thallus, whitish byssoid prothallus and C + red thallus, but C. bartlettii has delimited ascigerous areas (developing in the thallus centre and covered with globose isidia-like structures), 1 - spored asci and muriform ascospores ( Thor 1997).

Additional specimens examined.

China • Hainan Province, Baoting Li and Miao Autonomous County, Qixianling Hot Spring National Forest Park , 18°42'14.43"N, 109°41'47.92"E, alt. 325 m, on the bark of trees, 8 March 2023, J. X. Xue et al. 20230144 ( SDNU) ; • ibid., 20230145 ( SDNU) .

Figures

Figure 2. Cryptothecia disjecta (SDNU 20230144, type) A thallus and prothallus B pseudisidia. Scale bars: 500 µm (A); 200 µm (B).