Astrothelium supraclandestinum

The thallus of Astrothelium supraclandestinum is corticate, smooth to somewhat bullate, somewhat shiny, continuous, and greenish-grey, covering areas up to 7 cm (2.8 in) in diameter. It is approximately 0.1 mm thick and surrounded by a prothallus line, about 0.2 mm wide. The lichen infrequently induces somewhat spherical galls on the host bark.^[2]

Ascomata are pyriform, measuring about 0.5–0.8 mm in diameter, and are mostly aggregated in groups of 2–5, immersed in the bark tissue below pseudostromata. Pseudostromata are indistinctly delimited, not corticate, ochraceous or concolorous with the thallus, not much raised above the thallus, and up to 2 mm in diameter. The wall is black and up to about 60 μm thick. Ostioles are eccentric, fused, flat to convex, and brown to black. The hamathecium is not inspersed with oil globules. The asci contain 8 ascospores, which are hyaline, 5-septate, fusiform, and measure 50–75 by 14–22 μm.^[2]

In terms of standard chemical spot tests, the thallus surface is UV−, and the thallus medulla is K−. Thin-layer chromatography shows no secondary substances detected.^[2]

Astrothelium supraclandestinum is found on smooth bark of trees in primary forests. The species has been reported in Brazil, Venezuela, Australia, and Papua New Guinea.^[2]