Tephromela xanthonica Guzman-Guillermo 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 xanthonica

description: Tephromela xanthonica Guzmán-Guillermo, sp. nov.
(Figs 3G, H; 4E, F)
Similar to Tephromela velloziae, differing in its saxicolous ecology and its areolate thallus.
HOLOTYPE. — Mexico. Veracruz, Municipality of Las Vigas de Ramírez, locality of Volcancillo, alt. 2300 m, 19°37’00.5”N, 97°04’01.0”W, on volcanic rock, IX.2020, Cárdenas-Mendoza s.n. (holo-, XALU [XALU1413]; para-, XALU [XALU1414, XALU1415, XALU1416, XALU1417]).
ADDITIONAL SPECIMENS EXAMINED. — Brazil. Minas Gerais, Catas Altas, Caraça, alt. 1200-1400 m, 20°06’S, 43°29’W, on sandstone, 17-25.V.2021, L.A. Santos & Aptroot 52016, 52057 (ISE, CGMS).
ETYMOLOGY. — The name refers to its chemistry.
CHEMISTRY. — Thallus UV+ yellow, C-, P-, K-, apothecium margin UV+ yellow. With lichexanthone.
ECOLOGY AND DISTRIBUTION. — On exposed volcanic rock associated with Pinus forest in Volcancillo, Veracruz, and on sandstone in Campo rupestre in Caraça, Minas Gerais, Brazil; known from Brazil and Mexico.
MYCOBANK. — MB 846317.
DESCRIPTION
Thallus crustose, mineral to greenish-grey, rimose to verrucose, somewhat glossy, c. 0.3 mm thick, areoles 0.5-1 mm in diam. Prothallus absent. Photobiont an unicellular green alga, arranged in one layer below the cortex. Apothecia present, sessile, roundish to lobate when old, numerous on the center of the thallus. Disk black, 0.5-2.5 mm in diam., flat to slightly convex, epruinose. Thalline margin concolorous with the thallus, glossy, 0.15-0.18 mm wide, raised above the level of the disk, minutely crenate, with motes of white pruina when young. Proper exciple thickest at the base (50-60 µm), becoming thinner at the edges, intense yellowbrown. Hymenium c. 100-130 µm thick, pigment reddish purple, K+ purple. Subhymenium 80-90 µm thick, purple pigmented, dark purple in K. Epihymenium reddish-purple, pigment K+ purple. Paraphyses simple, septate, surrounded by dark red pigmented gel. Hypothecium 0-60 µm thick, with similar colorations as the hymenium. Asci slightly clavate, 65-55 µm tall, 8-spored. Ascospores simple, hyaline, ellipsoid, 9-13 × 5-6 µm, wall 1-2 µm thick. Pycnidia not observed.
DISCUSSION
Tephromela velloziae was described as containing lichexanthone and it also agrees in ascospore size (Kalb 1984). However, the isotypes Kalb 349 (B[B600157687, B600093712]) deposited in Herbarium Berolinense (digital material consulted in BiNHum 2021) and mentioned in the original description (Kalb 1984), differ morphologically and in ecology from the new species. They have a verrucose thallus without areoles, in contrast to the areolate thallus of T. xanthonica Guzmán-Guillermo, sp. nov. Also, T. velloziae grows on dead stems of a semi-woody herb in semi-arid Caatinga vegetation, whereas T. xanthonica Guzmán-Guillermo, sp. nov., is a saxicolous species, found growing on sandstone and on volcanic rock between species of Cladonia, Stereocaulon, Rhizocarpon, and other unidentified crustose lichens, in temperate to tropical montane ecosystem, including Pinus forest at 2250-2300 m in Mexico and campos rupestres at 1200-1400 m in Brazil.
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 pages 20-21, DOI: 10.5252/cryptogamie-mycologie2023v44a2, http://zenodo.org/record/7815402