Wirthiotrema xanthopustulatum Aptroot & M. F. Souza 2021, sp. nov.

Wirthiotrema xanthopustulatum Aptroot & M.F. Souza, sp. nov.

(Fig. 1I, J)

Corticolous sterile Wirthiotrema with thallus pale olivaceous metallic green, shiny, containing lichexanthone and protocetraric acid, pustules delimited, soredia globose to short ellipsoid, filled with small crystals, c. 45-100 µm diam.

MYCOBANK. — MB839449.

TYPE. — Brazil, Paraná, Guaraqueçaba, Tagaçaba Porto da Linha, road PR- 405 km 36.2, at right side of road, in chácara (property of Donald Schause), 14.X.2020, alt. 15 m, on tree bark, A. Aptroot & M.F. Souza 82093 (holo-, CGMS; iso-, ABL).

CHEMISTRY. — Thallus and pustules C-, UV + yellow, K-, P+ red, with lichexanthone and protocetraric acid, demonstated in tlc.

DESCRIPTION

Thallus corticolous, pale olivaceous metallic green, shiny, thin, IKI negative, covering an area of up to 10 cm diam., without prothallus line, but lower surface a continuous dark brown hypothallus. Algae trentepohlioid, green, c. 10-14 µm diam. Pustules delimited, of thallus colour or somewhat paler, starting as semiglobose c. 0.2 mm diam. warts, aggregating into mostly stalked, c. 0.5-2.0 mm diam, c. 0.5-1.7 mm high clusters, covering about quarter of the thallus surface. Soredia developing on top of abraded pustules, irregularly globose to short ellipsoid, IKI negative, filled with small crystals, c. 45-100 µm diam. Ascomata and pycnidia not observed.