Astrothelium trematum
| Astrothelium trematum | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Dothideomycetes |
| Order: | Trypetheliales |
| Family: | Trypetheliaceae |
| Genus: | Astrothelium |
| Species: | A. trematum
|
| Binomial name | |
| Astrothelium trematum | |
Astrothelium trematum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae,[1] first described in 2018. Found only in Brazil, it is characterised by its lack of lichexanthone and pigments, and distinctive ascospores.
Taxonomy
Astrothelium trematum was formally described by lichenologists Klaus Kalb and André Aptroot in 2018. The type specimen was collected near Caraguatatuba, São Paulo, Brazil, in a plantation of Theobroma cacao. The specimen was collected by the first author on 9 March 1980. The specific epithet trematum refers to the distinct ring around the ostiole that separates the ostiole from the thallus.[2]
Description
The thallus of Astrothelium trematum is dull, up to 0.3 mm thick, and pale olivaceous green, with a thick cortex and a medulla containing hyaline crystals. It is not surrounded by a prothallus. Ascomata are spherical to pyriform, 0.6–0.9 mm in diameter, solitary in pseudostromatal warts. The pseudostroma is low hemispherical, almost completely covered by a thallus layer, about 1–1.5 mm in diameter, and without pigmentation. Ostioles are apical, consisting of exposed carbonized, black ascoma wall, about 0.2 mm wide, surrounded by a whitish ring of approximately 0.3 mm in diameter. The hamathecium is not inspersed. Ascospores number eight per ascus, and are hyaline with 5 to 7 septa, measuring 95–135 by 25–33 μm. They have a long ellipsoid shape with internal diamond-shaped lumina. Pycnidia were not observed.[2]
The thallus of Astrothelium trematum is UV−, C−, K−, KC−, and P−. Thin-layer chromatography analysis did not detect any secondary metabolites.[2]
Habitat and distribution
Astrothelium trematum was found on tree bark in a cocoa plantation, and at the time of its original publication, was known only to occur in Brazil.[2]
References
- ^ "Astrothelium trematum Kalb & Aptroot". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 22 December 2023.
- ^ a b c d Kalb, K.; Aptroot, A. (2018). "New lichen species from Brazil and Venezuela". The Bryologist. 121 (1): 56–66. doi:10.1639/0007-2745-121.1.056.