Pleosporales » Leptosphaeriaceae » Sphaerellopsis

Sphaerellopsis isthmospora

Sphaerellopsis isthmospora A. Karunarathna, Phookamsak & K.D. Hyde, in Phookamsak et al., Fungal Diversity: 10.1007/s13225-019-00421-w, [28] (2019)

Index Fungorum number: IF556138         Facesoffungi number: FoF05698

 

Sexual morph: Ascomata 230–330 µm high, 260–510 µm diam., black, shiny, scattered, solitary to gregarious, erumpent through host epidermis, becoming semi-immersed to superficial, varied in shape, subglobose to mammiform, with flattened, quadrilateral, truncate base, uni-loculate, glabrous, ostiolate, minutely papillate. Ostioles central, with obtuse, minute papilla, dark brown to black, ostiolar

canal filled with periphyses. Peridium 18–60 µm wide, thick-walled of unequal thickness, thicker at the sides towards the apex, with flattened base, comprising several cell layers of black, coriaceous, pseudoparenchymatous cells, arranged in textura angularis to textura prismatica. Hamathecium initially comprising 2–5 µm wide, hyaline, filamentous distinctly septate pseudoparaphyses, laterally becoming, 6–18 µm wide, broadly cellular, hyaline, septate catenophyses, deeply constricted at the septa. Asci (120–)130–150 (–165) × (15–)19–23(–28) µm (x̄ = 141.4 × 21.6 µm, n = 20), 8-spored, bitunicate, fissitunicate, subcylindric-clavate, subsessile to short pedicellate, with truncate pedicel, apically rounded with well-developed ocular chamber. Ascospores (65–)75–95(–118) × 4–7 µm (x̄ = 87.1 × 5.9 µm, n = 30), isthmosporous, overlapping 2–3-seriate, hyaline to yellowish, elongate cylindrical to subcylindric-clavate, bent at the 8th septum, 10–12-septate, slightly constricted at the septa, deeply constricted at the 8th septum, split into two part-spores; upper part 40–70(–82) µm long, 5–7-septate, cylindrical, with rounded end; lower part 28–35(–50) µm long, 2–3-septate, subcylindric-clavate, with acute end, guttulate, lacking a mucilaginous sheath. Asexual morph: Undetermined.

 

Material examined: CHINA, Yunnan Province, Baoshan, Shuizai, Dawazi mountain, on dead branches of herbaceous plant, 23 October 2015, R. Phookamsak, BS012 (KUN-HKAS 102225, holotype).

 

GenBank Accession No: ITS: MK387925, LSU: MK387963, SSU: MK387933, TEF1-a: MK435604 (HKAS 102225A); ITS: MK387926, LSU: MK387964, SSU: MK387934, TEF1-a: MK435605 (HKAS 102225B).

 

Notes: Sphaerellopsis isthmospora forms a phylogenetically distinct lineage, but clusters with other Sphaerellopsis species in Leptosphaeriaceae. Sphaerellopsis isthmospora can be distinguished from other Sphaerellopsis species in its sexual morph having isthmosporous ascospores, with 10–12-septate, deeply constricted and bent at the 8th septum. Sphaerellopsis filum (sexual morph: Eudarluca caricis) has spindle-shaped, slightly inequilateral, 2–3-septate ascospores (Yuan et al. 1998). Based on morphological difference and phylogenetic affinity, we therefore, introduce a new species S. isthmospora from herbaceous plant in Baoshan, China.

Figure X. Sphaerellopsis isthmospora (KUN-HKAS 102225, holotype). a Appearance of ascomata on host substrate. b Section through ascoma. c Section through peridium. d, e Pseudoparaphyses. f–h Asci. i–n Ascospores. Scale bars a = 500 µm, b = 100 µlm, c = 50 µm, d–n = 20 µm.

 

Reference:

Phookamsak R, Hyde KD, Jeewon R, Bhat DJ, et al. (2019) Fungal diversity notes 929–1035: taxonomic and phylogenetic contributions on genera and species of fungi. Fungal Diversity (2019) 95:1–273

 

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