Astrothelium infravulcanum

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Astrothelium infravulcanum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Dothideomycetes
Order: Trypetheliales
Family: Trypetheliaceae
Genus: Astrothelium
Species:
A. infravulcanum
Binomial name
Astrothelium infravulcanum
Aptroot (2022)
Astrothelium infravulcanum
Holotype: Reserva extrativista, Acre, Brazil [1]

Astrothelium infravulcanum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. [2] This species was discovered in the rainforests of Acre, Brazil, and is distinguished by its unique features and chemical makeup.

Contents

Taxonomy

Astrothelium infravulcanum was formally described as a new species in 2022 by the Dutch lichenologist André Aptroot, in a study highlighting new lichen species from Brazil. The type specimen was collected by Marcela Cáceres and Aptroot from the Comunidade Cuidado in the Cazumbá-Iracema Extractive Reserve (Sena Madureira, Acre, Brazil); there, at an elevation of 150 m (490 ft), it was found growing on bark in a rainforest. The species name infravulcanum signifies its resemblance to Astrothelium vulcanum but with notably smaller spores, hence infra indicating "below" or "smaller than" in Latin, pointing to the smaller size of its spores compared to those of A. vulcanum. [1]

Description

The species showcases a pale ochraceous (yellowish-brown) thallus, which is the body of the lichen, lacking a prothallus (a preliminary growth phase or border). The thallus emits a yellow fluorescence under UV light, indicating the presence of specific chemicals. Its reproductive structures, called ascomata, are globose to pyriform (globe to pear-shaped), measuring 0.2–0.4 mm in diameter, and mostly embedded within the thallus rather than lying on a separate supportive structure. These structures have a single, black opening (ostiole) at the top through which spores are released. [1]

The internal structure ( hamathecium ) is interspersed with clear, oil-like globules. Spores are produced eight per ascus, are clear (hyaline), divided into three sections (3-septate), and measure 14–17 by 5–6  μm. These spores are long-ellipsoid in shape and do not have a surrounding gelatinous layer. The species does not form pycnidia, which are structures that produce asexual spores. [1]

Chemically, the thallus reacts to UV light by turning yellow but shows negative reactions to standard lichen spot tests (C, P, and K tests), indicating the absence of certain chemicals typically searched for in lichen studies. The only chemical detected through thin-layer chromatography is lichexanthone, a xanthone compound common in some lichens and known for its yellow fluorescence under long-wavelength UV light. [1]

Habitat and distribution

Astrothelium infravulcanum is corticolous, meaning it grows on tree bark, specifically within the humid and biodiverse ecosystem of a Brazilian rainforest. At the time of its original publication, the lichen was only known to exist in its type locality within the state of Acre, Brazil. [1]

Related Research Articles

Enterographa lichexanthonica is a species of crustose and corticolous (bark-dwelling) lichen in the family Roccellaceae. Found in the Brazilian Amazon, it was formally introduced as a new species in 2017 by lichenologists Marcela Eugenia Cáceres and André Aptroot. The type specimen was collected by the authors from the Adolfo Ducke Forest Reserve, along trails near a field station; here, it was found growing on tree bark in a old-growth rainforest. The lichen has a thin, dull, pale greenish thallus surrounded by a thin black prothallus. Its ascospores are hyaline, have seven septa, and measure 21–27 by 5–6 μm; they have a 1 μm-thick gelatinous sheath surrounding them. The specific epithet lichexanthonica refers to lichexanthone, a secondary chemical that occurs in the cortex of the lichen. This compound causes the lichen to fluoresce yellow when a UV light is shone upon it. Enterographa lichexanthonica is morphologically similar to E. kalbii, but this latter species has lichexanthone only on the ascomata, not on the thallus.

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 octoseptatum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by 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 rainforest. The lichen has a smooth and somewhat shiny, pale greenish-grey thallus that lacks a prothallus and covers areas of up to 7 cm (2.8 in) in diameter. The ascomata are pear-shaped (pyriform) and typically occur in groups of two to five, usually immersed in the bark tissue. The lichen contains lichexanthone, a substance that causes the surface of the pseudostroma to glow yellow when lit with a high-wavelength UV light. The species epithet octoseptatum refers to the ascospores, which usually have eight septa that divide the spore into distinct compartments.

Astrothelium quatuorseptatum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by André Aptroot and Marcela Cáceres. The type specimen was collected by the authors in the Estação Ecológica de Cuniã, in a low-altitude primary rainforest. The lichen has a smooth and somewhat shiny, pale greenish-grey thallus that lacks a prothallus and covers areas of up to 7 cm (2.8 in) in diameter. The ascomata are pear-shaped (pyriform) and typically occur in groups of two to five, usually immersed in the bark tissue. The lichen does not react with any of the standard chemical spot tests, and thin-layer chromatography did not reveal the presence of any lichen products. The species epithet quatuorseptatum refers to the ascospores, which usually have four septa that divide the spore into distinct compartments. A. octosporum is quite similar in appearance, but that species has twice the number of septa in its spores, and it contains lichexanthone.

Astrothelium eumultiseptatum 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 Fazenda São Francisco, in a low-altitude primary rainforest. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus with a black prothallus line and covers areas of up to 7 cm (2.8 in) in diameter. The ascomata are pear-shaped (pyriform) and typically aggregate in groups of two to five, usually immersed in the bark tissue as pseudostromata. The ostioles of the ascomata contains lichexanthone, a lichen product that causes these structures to glow yellow when lit with a long-wavelength UV light. The main characteristic that distinguishes it from other members of Astrothelium are its ascospores, which measure 65–70 by 15–17 μm, and only have transverse septa.

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 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 ochroleucoides is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is found in Brazil and Guyana.

Astrothelium xanthosuperbum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is found in Rondônia, Brazil. The species is characterized by its large muriform ascospores and is similar in appearance to Astrothelium disjunctum.

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Astrothelium tetrasporum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae, first described in 2016. It is found in Brazil.

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 longisporum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. It occurs in the Atlantic Forest of Brazil.

Astrothelium curvatum is a species of corticolous lichen in the family Trypetheliaceae. Found in Brazil, it was described as a new species in 2016. It is characterised by its immersed pyriform ascomata with lateral ostioles and bent, muriform ascospores.

Astrothelium gyalostiolatum is a species of corticolous (bark-dwelling) crustose lichen in the family Trypetheliaceae. Found in Brazil, it was described in 2022 by the Dutch lichenologist André Aptroot. It belongs to the genus Astrothelium, sharing similarities with Astrothelium bicolor but uniquely characterized by the presence of lichexanthone exclusively around the ostioles.

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.

Fissurina isohypocrellina is a species of corticolous (bark-dwelling), crustose lichen in the family Graphidaceae]. Newly described to science in 2022, it is found in the rainforests of Acre, Brazil. This species is notable within the genus Fissurina genus for the presence of isohypocrellin, a rare secondary metabolite that contributes to its unique wine-red apothecia.

References

  1. 1 2 3 4 5 6 Aptroot, André; de Souza, Maria Fernanda; dos Santos, Lidiane Alves; Junior, Isaias Oliveira; Barbosa, Bruno Micael Cardoso; da Silva, Marcela Eugenia Cáceres (2022). "New species of lichenized fungi from Brazil, with a record report of 492 species in a small area of the Amazon Forest". The Bryologist. 125 (3): 435–467. doi:10.1639/0007-2745-125.3.433.
  2. "Astrothelium infravulcanum Aptroot". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 2 March 2024.