Biology:Marcelaria
Marcelaria is a genus of crustose lichens in the family Trypetheliaceae.[1] It has three species.[2] These lichens grow as crusty patches on tree bark and are recognised by their bright orange, yellow, or red colouring. They produce distinctive flask-shaped fruiting bodies that are vividly pigmented and sit directly on the lichen's surface. The genus is found mainly in tropical regions of Asia, Africa, and the Americas.
Taxonomy
The genus was circumscribed in 2013 by André Aptroot, Matthew P. Nelsen, and Sittiporn Parnmen, with Marcelaria purpurina assigned as the type species. The genus contains species that were previously in the Laurera purpurina species complex. Species in Marcelaria contain secondary compounds such as red, orange, and yellow anthraquinones, and sometimes lichexanthone. The genus name honours Brazilian lichenologist Marcela Cáceres.[3]
In 2016, Aptroot and Nepi made a formal proposal to conserve the name Marcelaria over Buscalionia. This decision was necessitated by the rediscovery of type material originally described in 1940 by Maria Cengia Sambo as Buscalionia rubra,[4] which technically should take priority as per the rules of botanical nomenclature. Given the widespread recognition and use of the name Marcelaria, especially for the type species M. purpurina, the authors advocated for its conservation to maintain clarity and consistency in lichenological studies.[5] The proposal was rejected by the Nomenclature Committee for Fungi in 2023, who noted that the authors missed a critical 1953 annotation that identified the type of Buscalionia (B. rubra) as conspecific with Laurera purpurina, a species central to Marcelaria. Considering this oversight, the relatively short period during which Marcelaria had been used, and the fact that only three new combinations would be required if Buscalionia were adopted instead, the committee recommended against the conservation of Marcelaria.[6]
Description
Marcelaria forms a crust-like thallus on tree bark (corticolous). Part of the thallus can sit within the outer bark layer (endoperidermal). The surface "skin" ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) is thin, firm and slightly cartilage-like, and is built from hyphae arranged like vertical threads ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]). The photosynthetic partner is from the green algal genus Trentepohlia.
Sexual fruiting bodies are abundant and [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]—i.e. they resemble tiny, flask-like, single-chambered warts (unilocular) that sit directly on the thallus without a stalk ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]). They occur singly or in small groups, but do not merge into a larger compound structure (not [[Glossary of lichen terms#{{biology:{1}}}|pseudostromatic]]). Their outer covering is vividly pigmented in bright orange-yellow to red, and there is usually a visible split between the inner wall of the fruit body and the surrounding covering tissue. This covering is formed mainly by a thick, gelatinised inner [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] that turns green when treated with potassium hydroxide solution (the standard "K" spot test used by lichenologists).
Inside the fruiting bodies, the jelly-like matrix ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) contains thin, straight filaments that branch and interconnect ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) and do not react with iodine (IKI-negative). The asci have two separable wall layers ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]), show a broad, flat apical chamber ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]), are club-shaped with a short stalk, and are also IKI-negative. The spores are colourless, multi-celled with both cross- and longitudinal walls ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]), oblong-oval to ellipsoid or spindle-shaped, lack a dominant median septum, and have an inner spore wall ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) with rounded internal spaces ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]). Asexual structures (pycnidia) have a tiny pore-like opening (a [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] ostiole) and a characteristically brain-like, lobed interior; they produce colourless, rod-shaped conidia. Chemically, species contain several anthraquinone pigments in red, orange and yellow tones (sometimes concentrated in either the thallus or the fruiting bodies), and lichexanthone is often present.
Species
- Marcelaria benguelensis (Müll.Arg.) Aptroot, Nelsen & Parnmen (2013) – continental southeast Asia
- Marcelaria cumingii (Mont.) Aptroot, Nelsen & Parnmen (2013) – southeast Asia
- Marcelaria purpurina (Nyl.) Aptroot, Nelsen & Parnmen (2013) – neotropics; tropical West Africa
References
- ↑ "Marcelaria". Species 2000: Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/5L6R.
- ↑ Wijayawardene, Nalin; Hyde, Kevin; Al-Ani, Laith Khalil Tawfeeq; Somayeh, Dolatabadi; Stadler, Marc; Haelewaters, Danny et al. (2020). "Outline of Fungi and fungus-like taxa". Mycosphere 11: 1060–1456. doi:10.5943/mycosphere/11/1/8.
- ↑ Aptroot, A.; Nelsen, M.P.; Parnmen, S. (2013). "Marcelaria, a new genus for the Laurera purpurina group in the Trypetheliaceae (Ascomycota: Dothideomycetes)". Glalia 5 (2): 1–14. https://archive.org/details/2013_Glalia_5_2.
- ↑ Sambo, M. (1940). "Licheni del Brasile". Annali di Botanica 22: 19–41.
- ↑ Aptroot, André; Nepi, Chiara (2017). "(2492) Proposal to conserve the name Marcelaria against Buscalionia (Trypetheliaceae, lichenized Ascomycota)". Taxon 66 (1): 200–201. doi:10.12705/661.20.
- ↑ May, Tom W.; Lendemer, James C. (2023). "Report of the Nomenclature Committee for Fungi: 22". Taxon 72 (6): 1356–1363. doi:10.1002/tax.13099.
Wikidata ☰ Q32868220 entry
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