Astrothelium testudineum

Astrothelium testudineum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is found in Brazil.

Taxonomy

The lichen was fornally described as a new species in 2016 by lichenologists André Aptroot and Marcela Cáceres. Astrothelium testudineum is most similar to A. leioplacum, but it can be distinguished by its and larger .

Description

The thallus of Astrothelium testudineum is thickly , smooth, somewhat shiny, continuous, and ochraceous, covering areas up to in diameter. It is approximately 0.2 mm thick and surrounded by a black prothallus line, about 0.1 mm wide. The lichen does not induce gall formation on the host bark.

Ascomata are , measuring 0.5–0.9 mm in diameter, and are mostly aggregated in groups of 2–6, immersed in the thallus, without . The wall is all around, up to about 70 ÃŽÂ¼m thick. Ostioles are eccentric, fused, and flat, with a brown colour. is densely inspersed with hyaline oil globules. Asci contain 8 ascospores, which are hyaline, densely , broadly ellipsoid, and measure 50–65 by 23–27 ÃŽÂ¼m.

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

Habitat and distribution

Astrothelium testudineum is found on Hevea brasiliensis bark in plantations. The species is currently known only from Brazil.

References