Macroconstrictolumina megalateralis Aptroot sp. nov. (Fig. 79 g–k)

MycoBank number: MB 836793; Index Fungorum number: IF 836793; Facesoffungi number: FoF 08802.

Diagnosis: Corticolous Macroconstrictolumina with thallus UV-negative; ostioles lateral, ascospores granular ornamented, 34–37 × 11–14 µm, with gelatinous sheath of c. 4 µm.

Etymology: The epithet refers to the large ascomata and ascospores and the lateral ostioles.

Holotype: A. Aptroot 77751 (CGMS).

Thallus crustose, endoperidermal, whitish to pinkish, opaque, not surrounded by a prothallus. Ascomata solitary, pyriform, 0.6–0.8 mm diam., black. Ostioles lateral, black. Hamathecium clear. Ascospores 8/ascus, hyaline, 1-septate, septum median, 34–37 × 11–14 µm, sole-shaped with upper cell wider than lower cell, with conspicuous granular wall ornamentation, more or less distinctly constricted but not thickened at the median septum, with secondary constriction or invagination in each cell, surrounded by a c. 4 µm thick gelatinous sheath. Pycnidia not observed.

Chemistry: Thallus UV–, C–, P–, K–; no substances detected by TLC.

Ecology and distribution: On tree bark in Atlantic Forest; thus far only known from Brazil.

Material examined: Brazil. Mato Grosso do Sul: Serra da Bodoquena, Bonito, Fazenda Marambaia; 20°58’ S, 56°42’ W, 650 m; Atlantic Forest, on tree bark in pasture close to forest; 30 October 2018, A. Aptroot 77751 (holotype: CGMS; isotype: ABL); Serra da Bodoquena, Fazenda Monte Negro; 20°54’25″ S, 56°48’04″ W, 530 m; Atlantic Forest, on tree bark in forest; 8 November 2018, A. Aptroot 77888, 77930, 77933, 77940, 77941, 77948, 77966 (para-types: CGMS). Acre: Núcleo Cazumbá; 09˚07’ S, 68˚57’ W, 150 m; disturbed tropical rain forest; 2019, M. Cáceres & A. Aptroot (ABL, ISE 50171).

Notes: Four species of Macroconstrictolumina are so far recognized. The new species is unmistakable by the lateral ostioles.

Fig. 79 ad Bogoriella complexoluminata (holotype). a Thallus with ascomata. b–d Ascospores in various stages of development. e B. isthmospora (Aptroot s.n.), ascospores in various stages of development. f Schummia angulata (Aptroot 14061), ascospores in various stages of development. g–k Macroconstrictolumina megalateralis(holotype). g Thallus with ascomata. h Hamathecium and ascospores. i–k Ascospores in various stages of development. Scale bars: a, g = 1 mm, b–f, h–k = 10 µm. Photographs by André Aptroot except e and f, by Felix Schumm