Pyrenula rufotetraspora M. Z. Dou & Z. F. Jia sp. nov. Fig. 4 Etymology. The specific epithet rufo refers to the red oil in over-mature ascospores and tetraspora means that there are four spores in each ascus. Holotype. China • Guizhou Province, Libo County, Xiaoqikong Scenic Area, Laya Waterfall, 25°15'10"N, 107°44'06"E, alt. 425 m, on bark, 24 October 2018, Z. F. Jia (LCUF GZ 18377, holotype; GenBank PP 692371 for ITS, and PP 692474 for nuLSU). Diagnosis. This new species can be distinguished from the most similar species Pyrenula yunguiensis by fewer ascospores per ascus, bigger ascospores, more locules and different lichen substances. Description. Thallus corticolous, crustose, olive-green in the field and khaki after drying, surface dull, corticate with pseudocyphellae, UV-. Apothecia emergent, dispersed, conical, 0.6–1.2 mm diam., the sides often partly covered by the thallus, with crystals. Excipulum completely carbonized when mature and falls apart when over-mature. Ostioles apical, white or brown. Hamathecium not inspersed, IKI + red. Ascospores 4 per ascus, uniseriate, fusiform, with pointed or blunt ends, 70–100 (– 106) × (17 –) 21–27 (– 41) μm, hyaline to brown, muriform, with c. 10–12 × 3–14 locules, lumina rounded, old spores containing globules of red oily substance. Chemistry. Thallus UV-. TLC with solvent C showed one unidentified black spot at the dividing line of Rf three and four under 254 nm ultraviolet light; unidentified red substances at Rf four under 365 nm ultraviolet light (Suppl. material 3). Habitat and distribution. The new species is currently only known from the subtropical regions of southern China on bark. Notes. This new species is similar to Pyrenula seminuda, P. endocrocea, P. breutelii, P. macularis, P. submacularis and P. yunguiensis in having (sub) muriform ascospores with red or orange oil when over-mature. This new species differs from P. seminuda by bigger and muriform ascospores with more locules, the latter 22–40 × 10–17 μm and submuriform with 6 × 1–2 locules, most transverse locules being single and few with an oblique or longitudinal division (Aptroot et al. 2013). P. endocrocea differs from this new species by medulla with a soft layer of copious orange anthraquinone crystals reacting UV + red and KOH + crimson, and smaller ascospores, (30 –) 32–44 (– 50) × 13–16 (– 19) μm (Aptroot et al. 2012). This new species can be distinguished from P. breutelii, P. macularis, P. submacularis and P. yunguiensis by different lichen substances (Suppl. materials 3, 4), bigger ascospores, more locules and fewer ascospores per ascus. There are 8 ascospores in per ascus in P. breutelii, P. macularis, P. submacularis and P. yunguiensis, 4 in the new species. P. rufotetraspora showed a black spot at the dividing line of Rf three and four under 254 nm ultraviolet light (no. nr. 13 on Suppl. material 3), which was not red on charred plate under 365 nm ultraviolet light. This black spot did not exist in P. breutelii, P. macularis, P. submacularis and P. yunguiensis and located at Rf four under 254 nm ultraviolet light on Suppl. material 4 (no. nr. 16). The difference of locations of this spot on Suppl. materials 3, 4 might be caused by edge effect. P. submacularis is sister to P. rufotetraspora with high support (1 / 92), but the latter has fewer ascospores in ascus (4) and obviously bigger ascospores.

Published as part of Dou, Mingzhu, Li, Jiechen, Hu, Yongshun, Aptroot, André & Jia, Zefeng, 2024, Phylogenetic analysis shows that Pyrenula (Pyrenulaceae) diversity is larger than expected: three new species and one new record discovered in China, pp. 159-183 in MycoKeys 110 on pages 159-183, DOI: 10.3897/mycokeys.110.131741