Astrothelium xanthosordithecium | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Dothideomycetes |
Order: | Trypetheliales |
Family: | Trypetheliaceae |
Genus: | Astrothelium |
Species: | A. xanthosordithecium |
Binomial name | |
Astrothelium xanthosordithecium Aptroot (2022) | |
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Holotype: Santuário do Caraça, Brazil |
Astrothelium xanthosordithecium is a species of corticolous (bark-dwelling, crustose lichen in the family Trypetheliaceae. [1] The lichen grows in the rainforests of Minas Gerais, Brazil. It contains the chemical lichexanthone, a secondary metabolite that causes it to fluoresce when lit with an ultraviolet light.
The Dutch lichenologist André Aptroot formally described Astrothelium xanthosordithecium in 2022, highlighting its unique chemical composition compared to its closest relative, Astrothelium sordithecium . The species epithet xanthosordithecium alludes to its distinctive feature: the presence of lichexanthone, a yellow pigment, contrasting with the brownish hamathecium (a tissue in the ascomata containing spore-producing cells) inspersion of A. sordithecium. The type specimen was collected from the Santuário do Caraça in Minas Gerais, at an elevation between 1,200 and 1,400 m (3,900 and 4,600 ft). [2]
The thallus of Astrothelium xanthosordithecium is slightly shiny and olivaceous green, spreading up to 110 cm (43 in) in diameter and about 0.1 mm thick. It closely follows the substrate without forming a prothallus, an initial growth phase or border seen in other lichens. Reproductive structures (ascomata) are pear-shaped and fused, forming within pseudostromata , a tissue structure that houses multiple ascomata. These pseudostromata are often whitish, round to lobate, and can be 1–3 mm in diameter and 0.9–1.4 mm high. Each pseudostromatum typically has a single group of fused ascomata, thus a single ostiole (opening), which is black and eccentric (off-centre). [2]
The internal tissue, or hamathecium, contains tiny brownish oil globules. The lichen produces eight spores per ascus, which are clear (hyaline), dividided into four compartments by septa (3-septate), and measure 34–37 by 10–12 μm. These spores are long-ellipsoid in shape and do not have a surrounding gelatinous sheath. No pycnidia (structures for asexual reproduction) were observed. [2]
Chemically, both the thallus and pseudostromata show a yellow fluorescence under ultraviolet light. Thin-layer chromatography confirmed the presence of lichexanthone, a secondary metabolite that contributes to the lichen's unique characteristics. [2]
Astrothelium xanthosordithecium is closely related to Astrothelium sordithecium, sharing the habitat and the brownish hamathecium inspersion. However, it is distinguishable by its chemical composition, specifically the presence of lichexanthone, which sets it apart from any other species within Astrothelium. [2]
Astrothelium aeneoides is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. It is found in Brazil, Guyana, and Puerto Rico, where it grows on the smooth bark of rainforest trees.
Astrothelium stromatofluorescens is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is only known to occur in a few locations in Brazil and Bolivia.
Astrothelium lucidostromum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Guyana, it was formally described as a new species in 2016 by Dutch lichenologist André Aptroot. The type specimen was collected by Harrie Sipman about 45 km south of Aishalton at an altitude of 230 m (750 ft); there, it was found in a savanna forest growing on smooth tree bark. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus with a cortex but lacking a prothallus, which covers areas of up to 7 cm (2.8 in) in diameter. The presence of the lichen does not induce the formation of galls in the host plant. The pseudostromata contains lichexanthone, a lichen product that causes that structure to fluoresce when lit with a long-wavelength UV light. The main characteristics of the lichen distinguishing it from others in Astrothelium are the UV+ pseudostroma; the fused ascomata; and the immersed pseudostroma that have a white cover. Astrothelium eustomuralis is a smiliar species, but in that species, lichexanthone only occurs in the ostiole, not the entire pseudostroma.
Astrothelium eustomurale is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by lichenologists André Aptroot and Marcela Cáceres. The type specimen was collected by the authors in the Parque Natural Municipal de Porto Velho, in a low-altitude primary rainforest. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus that lacks a prothallus and covers areas of up to 12 cm (4.7 in) in diameter. The presence of the lichen does not induce the formation of galls in the host. The ascomata are pear-shaped (pyriform) and typically occur in aggregates of two to five, usually immersed in the bark tissue under the pseudostromata and with a whitish-coloured tissue that contrasts with the surrounding thallus. Black pycnidia are abundant on the pseudostromata. The area around and including the ostiole of the ascomata contains lichexanthone, a lichen product that causes these areas to glow yellow when lit with a long-wavelength UV light. The characteristics that distinguish it from other members of Astrothelium include the UV+ yellow nature of the ostiole; and the fused, erumpent pseudostromatic ascomata that have a white cover contrasting it with the thallus colour.
Astrothelium flavoduplex is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by lichenologists André Aptroot and Marcela Cáceres. The type specimen was collected by the authors in the Parque Natural Municipal de Porto Velho, where it was found growing on a twig in a low-altitude primary rainforest. The lichen has a smooth and somewhat shiny, olive-green thallus with a black prothallus line and covers areas of up to 8 cm (3.1 in) in diameter. The ascomata are more or less spherical and typically occur in groups of around 7 to 50, usually immersed in the bark tissue as pseudostromata. The thallus contains lichexanthone, a lichen product that causes the thallus surface to fluoresce yellow when lit with a long-wavelength UV light. The use of thin-layer chromatography on collected samples revealed the presence of an anthraquinone compound, possibly parietin. Astrothelium mesoduplex is similar in appearance, but that species lacks lichexanthone, and has shorter ascospores.
Astrothelium macrostomoides is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by Robert Lücking, Matthew Nelsen, Michel Navarro Benatti. The type specimen was collected by the first author from the Santuário do Caraça at an altitude between 1,300 to 1,400 m ; there, in the Atlantic Forest biome, it was found growing on bark in a gallery forest along a river. The lichen has an uneven to coarsely bullate, olive-green thallus that covers areas of up to 7 cm (2.8 in). Ascomata are in the form of perithecia, which are arranged in aggregated groups of 5–10 in pseudostromata. The pseudostromata contain lichexanthone, which is a lichen product that causes these structures to fluoresce yellow when lit with a long-wavelength UV light. The species epithet macrostomoides alludes to the similarity of the lichen with Astrothelium macrostomum, from which it differs by having larger ascospores. The characteristics of the lichen that distinguish it from others in genus Astrothelium are the diffusely pseudostromatic ascomata with erumpent pseudostromata, covered by thallus, each with a single group of fused ascomata; and the dimensions and form of the ascospores, which measure 80–110 by 17–25 μm, and have from five to seven septa.
Astrothelium pictum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by Dutch lichenologist André Aptroot. The type specimen was collected by the author from the Reserva Particular do Patrimônio Natural Santuário Caraça at an altitude of 1,300 m (4,300 ft); there, in an Atlantic Forest habitat, it was found growing on smooth tree bark.
Astrothelium chulumanense is a little-known species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in the Yungas montane forest of Bolivia, it was formally described as a new species in 2023. It is characterized by pseudostromata not differing in colour from the thallus, perithecia immersed for the most part in the thallus with the upper part elevated above and covered with orange pigment, apical and fused ostioles, the absence of lichexanthone, a clear hamathecium, eight-spored asci, and large, muriform ascospores with a thickened median septum.
Astrothelium mesoduplex is a species of lichen in the family Trypetheliaceae. It is similar to A. flavoduplex but has larger ascospores and lacks lichexanthone. This lichen species has been found only in Brazil, particularly in primary forests.
Astrothelium nigrum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is characterized by its conical black pseudostromata, which contrast sharply with the thallus. This lichen species has been found only in Brazil and is unique in its appearance, superficially resembling a Pyrenula species.
Astrothelium novemseptatum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It was first identified in Brazil, and has since been found in Guyana and Colombia. The lichen is characterized by its corticate, smooth, and somewhat shiny thallus, as well as its pyriform ascomata.
Astrothelium ochroleucoides is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is found in Brazil and Guyana.
Astrothelium supraclandestinum is a species of lichen in the family Trypetheliaceae. This lichen species is closely related to Astrothelium subclandestinum, but differs in its hamathecium, which is not inspersed. The species is widespread and has been observed in several countries across different continents.
Astrothelium conjugatum is a species of corticolous (bark-dwelling) crustose lichen in the family Trypetheliaceae, first described in 2016. It is known to occur in Sri Lanka.
Astrothelium megeustomum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae, first scientifically described in 2016. It is found in Brazil.
Astrothelium macrostomum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. It is found in Brazil, Guyana, and Venezuela.
Astrothelium graphicum is a species of lichen in the family Trypetheliaceae. This lichen features an extended, reticulate pseudostroma that is lower than its slightly bullate thallus.
Pseudopyrenula flavoreagens is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. It is found in Brazil and Panama, in both primary forest and disturbed rainforests.
Astrothelium infravulcanum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. This species was discovered in the rainforests of Acre, Brazil, and is distinguished by its unique features and chemical makeup.
Pyrenula musaespora is a species of corticolous (bark-dwelling), crustose lichen in the family Pyrenulaceae. Found in Brazil, this species is characterised by its pale ochraceous thallus and its filiform (thread-like) ascospores, which are 3–5-septate, meaning they are divided into several sections. The ascospores measure 30–37 μm by 3–4 μm.