The specific epithet murioelongata refers to the elongate, muriform ascospores.

China. Hainan Province: Ledong County, Jianfengling National Forest Park, 18°42'39"N, 108°52'37"E, alt. 760 m, on bark, 09 Dec 2019, Y. H. Ju HN19222 (LCUF: holotype: HN19222; GenBank MW009102 for ITS and MW010271 for LSU).

Thallus corticolous, crustose, olive-grey, surface dull, smooth to uneven, ecorticate. Apothecia erumpent, dispersed or two to four aggregated, rounded, 1–3 mm diam.; thalline margin lobed with white felt-like inner surface, lobes strongly backward curved; disc flesh-coloured, covered by thick, white pruina. Exciple 80–105 μm wide laterally, dark brown; epihymenium 20–40 μm high, with coarse greyish granules; hymenium clear, 110–170 μm high, non-amyloid; hypothecium colourless, 10–30 μm high; paraphyses simple, tips unbranched; periphysoides present, 5–30 μm long. Asci 4–6 (8)-spored, clavate, 100–120 × 35–50 μm; ascospores hyaline, bacillary with rounded to subacute ends, submuriform with 20–25 transverse septa and 0–2 longitudinal septa per segment, 75–105 × 9.5–16 μm, non-halonate, I-. Pycnidia not observed.

Thallus K-, C-, PD-; no compounds detectable by TLC.

On the bark in semi-exposed forest of Hainan Province.

China. Hainan Province: Changjiang County, Bawangling Nature Reserve, Yajia Scenic Area, 10°04'54"N, 109°07'04"E, alt. 810 m, on bark, 08 Dec 2019, Y. H. Ju HN19167 (LCUF); China. Hainan Province: Lingshui County, Diaoluo Mountain, 18°43'35"N, 109°52'02"E, alt. 900 m, on bark, 14 Dec 2019, M. Li HN19682 (LCUF) (GenBank MW009103 for ITS and MW010269 for LSU).

Chapsa murioelongata is characterised by its olive-grey thallus; white pruinose discs; distinct periphysoids; clear hymenium; 4–8-spored asci; submuriform ascospores with 20–25 transverse septa and 0–2 longitudinal septa per segment. Chapsa microspora Kalb, C. asteliae (Kantvilas & Vězda) Mangold, Astrochapsa elongata Poengs. & Lumbsch and C. patens are morphologically similar to the new species. Chapsa microspora can be distinguished from C. murioelongata by the smaller apothecia (0.6–1.2 mm diam.), transversely septate and smaller ascospores (7–9 × 4 μm) (Lumbsch et al. 2011). Chapsa asteliae differs in amyloid and shorter ascospores (30–80 μm) (Kantvilas and Vězda 2000; Mangold 2008). Astrochapsa elongata differs from C. murioelongata in having shorter ascospores (40–65 μm) and less longitudinal septa per segment (0–1) (Poengsungnoen et al. 2019). Chapsa patens differs from C. murioelongata chiefly in the single-spored asci and broader ascospores (22–35 μm) (Frisch 2006).

Blast searches of nuLSU sequences indicate Chapsa murioelongata has close affinities with C. patens (98.36% identity), C. wolseleyana (95.63% identity), C. leprocarpa (91.97% identity) and C. indica (90.81% identity), so all these species were included in the phylogenetic analyses. Chapsa murioelongata was well separated from any other species in the tree and strongly supported as the monophyletic (PP = 1; ML = 100%).

Thallus crustose, corticolous, grey-brown, surface dull to slightly shiny, uneven, fissured. Apothecia erumpent, dispersed, sometimes two or three fused, mostly rounded to seldom slightly angular, 0.7–1.2 mm diam.; thalline margin raised to lobulate, lobes erected to recurved, inner part brown, covered with rose-red or white pruina; disc exposed, rose-red, covered with thick, rose-red pruina. Exciple fused, cupular, laterally 180–250 μm wide, yellowish-brown to brown; epihymenium rose-red with granules, 20–50 μm high, K+ green; hymenium 140–230 μm high, clear, colourless, non-amyloid; hypothecium indistinct; paraphyses septate, tips rose-red and moniliform with oval or rectangular cells; periphysoides present, 50–100 μm long. Asci clavate, 1-spored, 110–135 × 35–50 μm; ascospores densely muriform, oblong-ellipsoid, with hemispherical to roundish ends, 105–130 × 30–45 μm, first reddish, becoming hyaline to slightly olive-brown at maturity, I-. Pycnidia not observed.

No substances detected by TLC but apothecial disc with pigment producing K+ yellow-green efflux, suggesting presence of isohypocrelline.

Growing on bark exposed to wind and high light intensity in montane forests. Worldwide distribution: Sri Lanka (Weerakoon et al. 2012) and newly reported for China.

China. Fujian Province: Quanzhou City, Jiuxian Mountain, Reflecting Pool, 25°42'57"N, 118°07'14"E, alt. 1540 m, on bark, 5 Jul 2019, F.Y. Liu FJ19148-b (LCUF) (GenBank MW009106 for ITS, MW010270 for LSU and MW010279 for SSU); China. Fujian Province: Quanzhou City, Jiuxian Mountain, Natural Observation Path, 25°42'44"N, 118°07'17"E, alt. 1460 m, on bark, 25 Jul 2019, F.Y. Liu FJ19158 (LCUF) (GenBank MW009078 for ITS, MW010273 for LSU and MW010277 for SSU). China. Fujian Province: Quanzhou City, Jiuxian Mountain, Reflecting Pool, 25°42'57"N, 118°07'14"E, alt. 1540 m, on bark, 25 Jul 2019, F.Y. Liu FJ19127-2, same locality, FJ19128-2, FJ19141-2 (LCUF).

Chapsa wolseleyana is characterised by its grey-brown, uneven thallus, apothecia with raised to lobed thalline margin, rose-red discs with similar coloured pruina, rose-red epihymenium and paraphyses tips, distinct periphysoids, 1-spored asci, muriform ascospores, red when young and hyaline to olive-brown when old. Only a few species of Chapsa have pigmented discs and among them C. rubropulveracea Hale ex Mangold, Lücking & Lumbsch is morphologically most similar to C. wolseleyana, but its thallus is farinose and its ascospores are 8 per ascus, smaller (15–20 ×5–6 μm) and transversely septate (Lumbsch et al. 2011).

Chapsa wolseleyana was transferred to Astrochapsa, based on a phenotype-based analysis (not molecular phylogeny) (Parnmen et al. 2012). However, our phylogenetic analysis shows that this species belongs in Chapsa, rather than Astrochapsa. Chapsa wolseleyana was associated phylogenetically with a strongly-supported clade (100/1) with C. patens, but with sufficient distance to be considered a distinct species. In addition, the latter differs from C. wolseleyana in having larger pale brown apothecia (up to 2 mm diam.) with white pruina, unpigmented epihymenium and unpigmented paraphyses adspersed with fine greyish to brownish granules, hyaline ascospores (Frisch et al. 2006; Joshi et al. 2012; Joshi et al. 2018).

Thallus corticolous, crustose, pale grayish-green surface dull and fluctuating along the bark. Apothecia erumpent, solitary to fused, angular rounded to slightly elongate, 0.5–1.8 × 0.5–1.2 mm; thalline margin split and recurved, insidewith thick white pruina; disc exposed, yellowish-brown, covered by white pruina. Exciple laterally 12–75 μm wide, dark brown; epihymenium 10–20 μm high; hymenium 120–200 μm high, grey-brown, inspersed by granules, non-amyloid; hypothecium indistinct; paraphyses unbranched; tips distinctly thickened; periphysoides present, but obscured by granular inclusions. Asci 1-spored, clavate, 120–140 × 27–36 μm; ascospores densely muriform, with thick halo at both ends, oblong, hyaline, 115–135 × 25–34 μm, I-. Pycnidia not observed.

Thallus K-, C-, PD-; no compounds detectable by TLC.

Growing on tree bark in tropical rainforests in altitudes ranging from 500 to 1100 m. Australia, Queensland (Mangold 2008); newly reported for China.

China. Hainan Province: Wuzhishan City, Wuzhishan Nature Reserve, 18°54'13"N, 109°41'04"E, alt. 870 m, on bark, 12 Dec 2019, M. Li HN19508 (LCUF) (GenBank MW009076 for ITS and MW010272 for LSU); China. Hainan Province: Wuzhishan City, Wuzhishan Nature Reserve, 18°53'13"N, 109°41'04"E, alt. 1020 m, on bark, 12 Dec 2019, M. Li HN19530 (LCUF); China. Hainan Province: Wuzhishan City, Wuzhishan Nature Reserve, 18°54'13'N, 109°41'04'E, alt. 870 m, on bark, 12 Dec 2019, M. Li HN19499 (LCUF); China. Hainan Province: Lingshui County, Diaoluo Mountain, 18°43'35"N, 109°52'02"E, alt. 900 m, on bark, 14 Dec 2019, M. Li HN19687 (LCUF); China. Hainan Province: Lingshui County, Diaoluo Mountain, 18°43'35"N, 109°52'02"E, alt. 900 m, on bark, 14 Dec 2019, M. Li HN19679 (LCUF).

Chapsa niveocarpa is characterised by its crustose, pale greyish-green thallus; rounded to elongate apothecia, yellowish-brown discs with white pruina, obscured periphysoids, inspersed hymenium, 1-spored(rare 2-spored)ascus and muriform and hyalineascospores with halo. Chapsa niveocarpa is morphologically similar and phylogenetically related to C. leprocarpa, and both species occur on bark in tropical forests (Frisch 2006; Mangold 2008; Parnmen et al. 2012). Chapsa leprocarpa differs from C. niveocarpa in having a lower hymenium (100–130 μm) and smaller ascospores (up to 111 μm long) (Frisch 2006). The specimen (HN19508) we collected in China is allocated phylogenetically to a strongly-supported (1/91) clade with C. niveocarpa. The collections cited above are the first reports for China.