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
[edit]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
[edit]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
[edit]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
[edit]- ^ "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.