Biology:Lecanactis rubra
| Lecanactis rubra | |
|---|---|
Scientific classification 
| |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Arthoniomycetes |
| Order: | Arthoniales |
| Family: | Roccellaceae |
| Genus: | Lecanactis |
| Species: | L. rubra
|
| Binomial name | |
| Lecanactis rubra Ertz & Sérus. (2009)
| |
Lecanactis rubra is a species of corticolous (bark-dwelling), crustose lichen in the family Roccellaceae.[1] Found in Madagascar, it was formally described as a new species in 2009 by Damien Ertz and Emmanuël Sérusiaux. The type specimen was collected by Sérusiaux from the gorge of Manambolo (Mahajanga Province) at an elevatin of 300 m (980 ft). At this location, about 3 km (1.9 mi) upstream from Bekopaka, in a dry forest with calcareous soil, it was found growing on bark. This lichen is only known to occur at the type locality.[2]
Description
Lecanactis rubra forms a thin, crust-like film on tree bark. The thallus is pale cream and [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], often cracked into tiny angular islands or puckered into low warts, yet it is only about 50–115 μm thick. Because it lacks a true [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], the surface is simply a tangle of colourless fungal threads 2–3 μm wide that are dusted with minute crystals which dissolve in potassium hydroxide solution (K). A dark-brown, felt-like [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] up to 0.4 mm wide sometimes rims the colony. The photosynthetic partner is the orange-green alga Trentepohlia; its cells are roughly 10–17 μm long and sit in loose bundles beneath the fungal layer.[2]
Fruiting bodies (ascomata) rise directly from the thallus as tiny cushions 0.5–1.5 mm across. They are usually rounded but can become [[Glossary of lichen terms#{{biology:{1}}}|lobed]], elongated into short slits ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) or, when several fuse, develop a brain-like outline. Each ascoma bears a flat [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] that is blanketed by dense white [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]—a frost-like powder that may show an orange tinge. The supporting wall ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) is built from intricately interwoven hyphae and is packed with reddish crystals that turn purple in K, an unusual feature caused by an anthraquinone pigment; the same wall is about 45–50 μm thick at the sides and thickens to 75–100 μm beneath the hymenium. Internally, a clear to orange-tinged hymenium 75–100 μm tall overlies a thin subhymenium that stains blue in iodine. Slender, branched paraphyses thread through the hymenium, whilst eight-spored asci (55–75 × 12–17 μm) show a distinct blue apical ring with iodine staining—an anatomical hallmark of the genus.[2]
The colourless ascospores are spindle-shaped, divided by three transverse walls formed in sequence from the middle outwards, and measure 22.5–27.0 × 5.5–6.0 μm; they remain straight and do not pinch at the septa. Chemical tests reveal gyrophoric acid in both thallus and apothecia (C+ fleeting red) and confirm the presence of the aforementioned anthraquinone (K+ red to purple). Together, the cream ecorticate thallus, white-pruinose red-crystal apothecia, and relatively broad three-septate spores readily separate L. rubra from all other species in the genus.[2]
Habitat and distribution
Lecanactis rubra is known only from its type locality, a dry deciduous forest on limestone in western Madagascar, where it was observed to be locally common at about 300 m elevation.[2] It is one of two Lecanactis species that have been documented from Madagascar; the other is L. spermatospora.[3]
References
- ↑ "Lecanactis rubra Ertz & Sérus.". Species 2000: Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/3SR25.
- ↑ 2.0 2.1 2.2 2.3 2.4 Ertz, Damien; Sérusiaux, Emmanuël (2009). "A new species of Lecanactis (Arthoniales, Roccellaceae) from Madagascar". The Lichenologist 41 (2): 147–150. doi:10.1017/S0024282909008287. Bibcode: 2009ThLic..41..147E. http://orbi.ulg.ac.be/handle/2268/10116.
- ↑ Aptroot, André (2016). "Preliminary checklist of the lichens of Madagascar, with two new thelotremoid Graphidaceae and 131 new records". Willdenowia 46 (3): 349–365. doi:10.3372/wi.46.46304. Bibcode: 2016Willd..46..349A.
Wikidata ☰ Q10555460 entry
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