Tephromela obesimarginata L. A. Santos, Aptroot & M. Caceres 2023, sp. nov.
Creators: name: Santos, Lidiane Alves dos
name: Aptroot, André
name: Souza, Maria Fernanda de
name: Lücking, Robert
name: Guzmán-Guillermo, Jorge
name: Cáceres, Marcela Eugenia da Silva
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Fungi
Ascomycota
Lecanoromycetes
Lecanorales
Tephromelataceae
Tephromela
Tephromela obesimarginata

description: Tephromela obesimarginata L.A.Santos, Aptroot & M.Cáceres, sp. nov.
(Figs 3C, D; 4A, B)
Similar to Tephromela velloziae but corticolous and differing in the unevenly thickened thalline apothecium margin and the larger ascospores.
HOLOTYPE. — Brazil. Minas Gerais, Catas Altas, Caraça, alt. 1200- 1400 m, 20°06’S, 43°29’W, on tree bark, 17-25.V.2021, L.A. Santos & A. Aptroot s.n. (holo-, ISE [ISE52321]; iso-, CGMS).
ADDITIONAL SPECIMENS EXAMINED. — Brazil. Minas Gerais, Catas Altas, Caraça, alt. 1200-1400 m, 20°06’S, 43°29’W, on tree bark, 17-25.V.2021, L.A. Santos & A. Aptroot 52143, 52312, 52309 (ISE, CGMS).
ETYMOLOGY. — The species is named after the irregularly thickened, plump, thalline apothecium margin.
CHEMISTRY. — Thallus UV+ yellow, C-, P-, K-, apothecium margin UV+ yellow. With lichexanthone.
ECOLOGY AND DISTRIBUTION. — On exposed trees in Campo rupestre vegetation in SE Brazil; known only from Brazil.
MYCOBANK. — MB 846315.
GENBANK. — OP881898.
DESCRIPTION
Thallus crustose, whitish to pale ochraceous-grey, rimose to areolate, verrucose,somewhat glossy, c. 0.1 mm thick.Prothallus absent. Photobiont an unicellular green alga, arranged in one layer below the cortex, algal layer c. 50 µm high. Apothecia always present, sessile, roundish, homogeneously distributed on the thallus, with unevenly crenate, irregularly thickened margin. Disk black, 0.7-2 mm in diam., flat to somewhat concave or saddle-shaped, epruinose. Thalline margin concolorous with the thallus, c. 0.2-0.6 mm wide, raised above the level of the disk (100-150 µm). Proper exciple thickest at the base, becoming thinner at the edges, pale to intense yellow-brown, intensifying yellow in K. Exciple with crystals that after treatment with K partly or completely dissolve. Hymenium c. 100-150 µm thick, violet, K+ greenish-grey. Epihymenium violet, K+ greenish-grey. Paraphyses simple, septate, 2-3 µm wide, with 3-5 µm wide hyaline apical cells, surrounded by violet pigmented gel.Hypothecium 100-150 µm thick, violet, K+ greenish-grey, with a narrow golden-brown band below the hymenium (25-50 µm thick). Asci slightly clavate, 50-75 µm tall, 8-spored. Ascospores simple, hyaline, ellipsoid, 14-16 × 6.5-7.5 µm. Pycnidia black. Conidia not observed.
DISCUSSION
The new species somewhat resembles Tephromela velloziae, but differs in the irregularly thickened apothecium margin, the larger ascospores (14-16×6.5-7.5 µm vs 9-12× 5-7 µm), and the corticolous habit.
description: Published as part of Santos, Lidiane Alves dos, Aptroot, André, Souza, Maria Fernanda de, Lücking, Robert, Guzmán-Guillermo, Jorge & Cáceres, Marcela Eugenia da Silva, 2023, Four new species of Tephromela M. Choisy (Ascomycota, Tephromelataceae), three containing lichexanthone, from Brazil and Mexico, pp. 11-25 in Cryptogamie, Mycologie 20 (2) on page 18, DOI: 10.5252/cryptogamie-mycologie2023v44a2, http://zenodo.org/record/7815402