Aggregatorygma lichexanthonicum

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Aggregatorygma lichexanthonicum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Graphidales
Family: Graphidaceae
Genus: Aggregatorygma
Species:
A. lichexanthonicum
Binomial name
Aggregatorygma lichexanthonicum
Aptroot (2022)
Aggregatorygma lichexanthonicum
Holotype: Reserva Cristalino, Mato Grosso, Brazil [1]

Aggregatorygma lichexanthonicum is a species of corticolous (tree-bark dwelling), crustose lichen in the family Graphidaceae. [2] Found in Brazil, it is characterised by the presence of lichexanthone in its thallus.

Contents

Type

The lichen was formally described in 2022 by the Dutch lichenologist André Aptroot. The type specimen was collected by the author in Reserva Cristalino in Mato Grosso, Brazil, at an altitude of 250–350 m (820–1,150 ft); there, it was found growing on tree bark within a primary rainforest. The species name alludes to its chemical marker, lichexanthone. This species is the third identified within its genus, all of which were described from Brazil. [1]

Description

The thallus of Aggregatorygma lichexanthonicum is crustose and continuous, extending up to about 20 cm (8 in) in diameter and up to 0.1 mm thick. It appears rather smooth and dull, almost white, and lacks a prothallus border. The photobiont within is trentepohlioid (green algae). Ascomata (fruiting bodies) are superficial on the thallus, sessile with a constricted base, initially solitary but soon dividing into aggregates of linear, simple or slightly branched lirellae within a pseudostroma that is distinctly lobate in outline. Pseudostromata measure 1–4 mm in width and 0.4–0.7 mm in height, with individual lirellae 0.2–0.4 mm wide and up to 3 mm long. The disc is pale grey and densely white pruinose , often showing splits or cracks. The epihymenium is brownish with numerous small crystals, likely calcium oxalate, while asci are dextrinoid . Ascospores , uniquely singular per ascus, are hyaline and densely muriform . Pycnidia have not been observed to occur in this species. [1]

Chemistry

Chemical analysis reveals the thallus to be UV+ (yellow) and the disc UV+ (bluish white), with spot tests for C, K, KC, and P being negative. Thin-layer chromatography shows the presence of lichexanthone. [1]

Habitat and distribution

Aggregatorygma lichexanthonicum is found exclusively on tree bark within primary rainforests in 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 corallinum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Guyana, it was formally described as a new species in 2016 by André Aptroot. The type specimen was collected from Rain Mountain, southeast of the village in Paruima Mission at an altitude of 500 m (1,600 ft); here, it was found growing on the smooth bark of trees in a rainforest. The lichen has a smooth, somewhat shiny thallus that covers areas of up to 8 cm (3.1 in) in diameter; the entire thallus is surrounded by a thin (0.3 mm) black line that is the prothallus. The whitish parts of the pseudostromata will fluoresce yellow when lit with a long-wavelength UV light; this is due to the presence of lichexanthone, a lichen product. The thallus, however, does not contain lichexanthone, which distinguishes it from the similar species A. ochroleucoides.

Astrothelium septemseptatum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Formally described as a new species in 2016 by Dutch lichenologist André Aptroot, it is found in Guyana and Venezuela, where it grows on trees in savanna and rainforest. The type specimen was collected by Harrie Sipman about 3 km (1.9 mi) south of Kuyuwini Landing at an altitude of 230 m (750 ft); there, it was found growing on smooth tree bark. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus with a cortex and a thin black prothallus line. It covers areas of up to 9 cm (3.5 in) in diameter. The presence of the lichen does not induce the formation of galls in its host plant. Both the thallus and the pseudostroma contain lichexanthone, a lichen product that causes these structures to fluoresce yellow when lit with a long-wavelength UV light. The combination of characteristics of the lichen that distinguish it from others in Astrothelium are the presence of lichexanthone in thallus and ascomata, and the ascospores, which are divided by from 7 to 9 septa and have dimensions of 50–55 by 12–17 μm.

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 sinuosum 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 André Aptroot and Emerson Gumboski. The type specimen was collected by the second author from the Rio Pardinho e Rio Vermelho Environmental Protection Area ; 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.

Chiodecton xanthonosorediatum is a species of corticolous (bark-dwelling), crustose lichen in the family Roccellaceae. It is native to Brazil, where it occurs in the Atlantic Forest. The lichen was formally described as a new species in 2020 by Dutch lichenologist André Aptroot. The type specimen was collected by the author from Serra da Bodoquena at an altitude of 460 m (1,510 ft).

Astrothelium miniannulare is a species of crustose lichen in the family Trypetheliaceae, characterized by its corticolous (bark-dwelling) habitat and presence of lichexanthone. Characteristics of the lichen include the whitish ring around its ostiole and the presence of three septa in the ascospores.

Astrothelium rhinothallinum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae, first described in 2018. It is found in Brazil.

Polymeridium longiflavens 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.

Diorygma isidiolichexanthonicum is a species of corticolous (bark-dwelling), crustose lichen in the family Graphidaceae. It is found in the Atlantic Forest of Brazil.

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.

Allographa pruinodisca is a species of corticolous (bark-dwelling) crustose lichen in the family Graphidaceae. It occurs in Brazil.

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.

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.

References

  1. 1 2 3 4 5 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. "Aggregatorygma lichexanthonicum Aptroot". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 29 February 2024.