Trypethelium muriforme Aptroot & M.F. Souza, 2021

Aptroot, André, Souza, Maria Fernanda & Spielmann, Adriano Afonso, 2021, Two new crustose Cladonia species with strepsilin and other new lichens from the Serra de Maracaju, Mato Grosso do Sul, Brazil, Cryptogamie, Mycologie 20 (8), pp. 137-148 : 147

Trypethelium muriforme Aptroot & M.F. Souza , sp. nov

(Fig. 5)

MYCOBANK. — MB 83950.

DIAGNOSIS. — Corticolous Trypethelium with thallus UV+ yellow and pseudostroma UV-negative, ascospores muriform, 50-70 × 10-13 µm.

TYPE. — Brazil. Mato Grosso do Sul, Aquidauana, 2 km SW of Piraputanga, alt. 175 m, 20°29”S, 55°33’17”W, on bark, 27.XI.2019, A.Aptroot & M.F. Souza 81448 (holo-, CGMS; iso-, ABL).

ADDITIONAL MATERIAL STUDIED. — Brazil. Mato Grosso do Sul:Aquidauana, 2 km SW of Piraputanga, alt. 175 m, 20°29’S, 55°33’17”W, on bark, 27.XI.2019, A.Aptroot & M.F. Souza 81453 (para-, CGMS).

CHEMISTRY. — Thallus UV+ yellow, K-; pseudostromata UV-. TLC: lichexanthone.

ETYMOLOGY. — Named after the muriform ascospores.

ECOLOGY AND DISTRIBUTION. — On tree bark in cerrado forest; only known from Brazil.

DESCRIPTION

Thallus dull, pale olivaceous greenish, with pale whitish patches, not surrounded by a prothallus. Ascomata globose to pyriform, 0.4-0.6 mm diam., single or immersed in pseudostromata, in groups of 2-6. Pseudostroma conspicuous, erumpent to prominent and then constricted, outline roundish to lobate,top convex, sides curved, c. 0.5-2.5 mm diam., initially whitish, later black because the wall becomes exposed, without pigment. Ostioles apical, single, brown to black, 0.2-0.4 mm diam. Hamathecium not inspersed. Ascospores 8/ascus, hyaline, muriform, 9-13 × 1-3-septate, 50-70 × 10-13 µm, fusiform, asymmetrical with the central primary septum well above the middle, markedly constricted at the primary septum with irregularly rounded to ellipsoid lumina of rather different size, not surrounded by a gelatinous sheath. Pycnidia not observed.