Biology:Aggregatorygma lichexanthonicum
| Aggregatorygma lichexanthonicum | |
|---|---|
Scientific classification 
| |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Graphidales |
| Family: | Diploschistaceae |
| Genus: | Aggregatorygma |
| Species: | A. lichexanthonicum
|
| Binomial name | |
| Aggregatorygma lichexanthonicum Aptroot (2022)
| |
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| 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.
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 [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] within is [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (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 [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] within a pseudostroma that is distinctly [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] in outline. [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] 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 [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is pale grey and densely white [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], often showing splits or cracks. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is brownish with numerous small crystals, likely calcium oxalate, while asci are [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]. [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], uniquely singular per ascus, are hyaline and densely [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]. 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]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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.
- ↑ "Aggregatorygma lichexanthonicum Aptroot". Species 2000: Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/B32F9.
Wikidata ☰ Q124708488 entry
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