Biology:Malmidea albomarginata
| Malmidea albomarginata | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Malmideaceae |
| Genus: | Malmidea |
| Species: | M. albomarginata
|
| Binomial name | |
| Malmidea albomarginata Kalb & J.E.Hern.(2021)
| |
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| Holotype site: Cerro El Volcán, Venezuela | |
Malmidea albomarginata is a species of corticolous (bark-dwelling), crustose lichen in the family Malmideaceae.[1] It is found in Venezuela.
Taxonomy
The lichen was formally described as a new species in 2021 by the lichenologists Klaus Kalb and Jesús Maldonado. The type specimen was collected by the authors from the Cerro El Volcán (Miranda) at an elevation of 1,460 m (4,790 ft); there it was found growing in a disturbed tropical mountain rainforest. The species epithet albomarginata alludes to the distinctive white margins that characterise its apothecia.[2]
Description
Malmidea albomarginata is a crustose lichen with a continuous thallus measuring 200–300 µm in thickness. The thallus surface is initially [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], with [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] being scarce and unevenly distributed, each measuring 0.1–0.3 mm in height and 0.15–0.3 mm in width. Over time, the thallus becomes dull and transforms from grey or greenish-grey to a coralloid [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] texture as it ages. This species lacks soralia and isidia. The medulla of both the verrucae and thallus is white to faintly yellow, reacting K+ (orange to reddish) when tested with potassium hydroxide, but without a reaction to the P spot test. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], with cells around 6–8 µm in diameter.[2]
Apothecia in Malmidea albomarginata are sessile and rounded, ranging from 0.8–1.8 mm in diameter and 0.2–0.3 mm in height. The apothecial [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] are flat to slightly convex, with colours varying from ochre to light greyish-brown. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is of the granifera type, [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], thin, and white. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is hyaline, while the medullary excipulum is whitish to slightly yellowish, filled with opaque, greyish to yellowish [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] that partially dissolve in KOH, producing a K+ (orange-red) efflux. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is about 25 µm high and hyaline to light brown, while the centrally located [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is 100–150 µm high, narrowing towards the margin and dark brown, showing no reaction to K tests. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is indistinct, and the hymenium measures 75–90 µm in height, being hyaline. Asci are sized 65–80 µm by 12–18 µm, containing 6–8 non-septate, [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], ellipsoid ascospores per ascus, measuring (10–)14 by 6–9 µm, with a [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] of 1.5–2 µm.[2]
Chemically, Malmidea albomarginata primarily contains atranorin, alongside several unidentified xantholepinones. It is distinguished from similar species like Malmidea attenboroughii by differences in apothecia size and the presence of atranorin. In comparison with Malmidea aurigera and Malmidea piperina, Malmidea albomarginata features larger apothecia, a paler apothecial disc, and warts that become coralloid granular.[2]
References
- ↑ "Malmidea albomarginata Kalb & J. Hern.". Species 2000: Naturalis, Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/B386M.
- ↑ 2.0 2.1 2.2 2.3 Kalb, Klaus (2021). "New or otherwise interesting lichens mainly from Brazil and Venezuela with special reference to the genus Malmidea". Archive for Lichenology 27: 1–41. http://www.fschumm.de/Archive/Vol%2027_Kalb_%20Brazil%20and%20Venezuela.pdf.
Wikidata ☰ Q123983198 entry
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