Imsharria

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Imsharria
Imsharria orangei.png
Holotype specimen of Imsharria orangei;
scale bar = 1 mm
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecideales
Family: Lecideaceae
Genus: Imsharria
Fryday & U.Rupr. (2024)
Species:
I. orangei
Binomial name
Imsharria orangei
Fryday & U.Rupr. (2024)
Imsharria
Holotype: Mount Adam, Falkland Islands

Imsharria is a fungal genus in the family Lecideaceae. [1] It comprises the single species Imsharria orangei, a rare saxicolous (rock-dwelling), crustose lichen. Endemic to the Falkland Islands, the lichen can be recognised by its sunken brown apothecia (fruiting bodies) and grey thallus with its distinctive paler margin. It is usually found on or near mountain summits, particularly in areas of broken rock (stone runs) and sparsely vegetated rocky ground (feldmark).

Contents

Taxonomy

Imsharria is a monospecific genus of crustose lichen in the family Lecideaceae. The genus was circumscribed in 2024 by Alan M. Fryday and Ulrike Ruprecht, with I. orangei designated as the type species. The genus was named to commemorate the lichenologists Henry Imshaug and Richard Harris, who conducted extensive lichen collecting work in the Falkland Islands during the austral summer of 1968–1969. The species epithet honours the British lichenologist Alan Orange, who also visited the islands and studied the lichen funga there. [2]

The genus is distinguished from other members of Lecideaceae by several key characteristics: [2]

Initially, specimens of this genus were provisionally assigned to the South African genus Schizodiscus , as both genera share features like Porpidia-type asci and an unpigmented hypothecium. However, molecular analysis showed only 75% sequence homology between Imsharria and Schizodiscus, indicating they are not closely related. [2]

Phylogenetic studies place Imsharria as a distinct lineage that is basal to other major groups within Lecideaceae, separate from both Lecidea and Porpidia clades. The genus forms a well-supported independent branch in molecular analyses, confirming its status as a separate genus within the family. [2]

Description

Imsharria orangei forms a thin, whitish to blue-grey crust (thallus) on rock surfaces, typically only 0.1–0.2 mm thick. The thallus has a distinctive appearance, with the outer 0.5–1.0 mm being noticeably paler than the central portions. It grows in small, flat to slightly concave segments ( areoles ) that measure 0.1–0.3 mm across. These segments develop on top of a black foundation layer called a prothallus , which is visible as a thin black border around the edge of the lichen. [2]

The reproductive structures (apothecia) are deeply sunken below the surface of the thallus. They appear as brown, disc-like depressions typically surrounded by a crack that separates them from the surrounding thallus. Initially round and measuring 0.4–0.6 mm in diameter, they can become irregular or elongated as they develop, sometimes forming slit-like shapes up to 0.7 mm long. Each apothecium has a thin, raised rim ( proper margin ) that is black or grey with a white inner edge. [2]

When examined microscopically, the thallus shows several distinct layers. The upper surface layer ( cortex ) is mostly colourless except for its uppermost portion, which contains a blue-black pigment. Below this lies a layer containing the photobiont (green algal partner) in clusters, rather than forming a continuous sheet. The internal layer (medulla) is composed of loosely interwoven colourless filaments (hyphae) and turns violet when stained with iodine solution, a distinctive chemical reaction that helps identify this species. [2]

The spore-producing structures (asci) are cylindrical and contain simple , colourless spores. These spores are surrounded by a gelatinous coating ( perispore ) that becomes more visible when treated with certain chemicals. When tested with chemical spot tests, the lichen shows a distinctive red reaction with potassium hydroxide solution (K) due to the presence of norstictic acid, a characteristic lichen product. [2]

Habitat and distribution

Imsharria orangei is endemic to the Falkland Islands, where it is known only from rocky outcrops at or near mountain summits. The species has been documented at several locations across both East and West Falkland, including Mt. Usborne, Mt. Kent, Mt. Maria, and Mt. Adam. [2]

The lichen shows a strong preference for siliceous (silicon-rich) rock surfaces, particularly in two specific habitat types: stone runs and feldmark. Stone runs are distinctive geological features in the Falklands consisting of large accumulations of broken rock fragments, while feldmark refers to sparsely vegetated rocky areas typical of exposed alpine environments. The species has been recorded at elevations up to at least 620 metres above sea level. At Mt. Adam, where the type specimen was collected, I. orangei was found growing on rocks near a tarn (mountain lake) in a southwestern cirque. [2]

Related Research Articles

<i>Psora</i> Genus of lichens

Psora is a genus of lichen-forming fungi in the family Psoraceae. Members of the genus are commonly called fishscale lichens. Lichens in the genus Psora generally have a squamulose thallus and anthraquinones in the hymenium. Photobiont partners of Psora lichens include members of the green algal genera Asterochloris, Chloroidium, Myrmecia, and Trebouxia.

<i>Herteliana</i> Genus of lichen-forming fungi

Herteliana is a genus of lichen-forming fungi. It contains four species of crustose lichens.

<i>Schadonia</i> Genus of lichen-forming fungi

Schadonia is a genus of lichen-forming fungi. Established by German lichenologist Gustav Wilhelm Körber in 1859, this genus of crustose lichens is characterised by its black, sessile apothecia, muriform ascospores, and growth on mosses, plant debris, and rocks in montane habitats. While traditionally placed in the family Ramalinaceae, recent studies have suggested its classification may be uncertain within the order Lecanorales, with some researchers proposing its placement in the Pilocarpaceae or the resurrection of the family Schadoniaceae. The genus currently comprises four recognised species.

<span class="mw-page-title-main">Lecideaceae</span> Family of lichen-forming fungi

The Lecideaceae are a family of lichen-forming fungi in the order Lecideales. It contains about 30 genera and roughly 250 species. A major distinguishing characteristic of the family is the lecanoroid form of the fruiting bodies: typically circular, dark, and without a thalline margin. Most species in the family are lichenised with green algae, although a few species, scattered amongst several genera, are lichenicolous—they live on other lichens. Lecideaceae lichens tend to grow on rocks, wood, and soil. Several Lecideaceae species accelerate the weathering of rock surfaces, a process known as pedogenesis, by extending their hyphae into cracks and expelling rock flakes. This contributes to significantly faster weathering rates in certain environments, impacts various materials from natural rocks to man-made Sekishu roof tiles, and involves key biomolecules identified for survival and biodeterioration, including compounds to withstand intense ultraviolet radiation.

<i>Immersaria</i> Genus of lichen

Immersaria is a genus of lichen-forming fungi in the family Lecideaceae. It has eight species of crustose lichens.

<i>Porpidia</i> Genus of lichen-forming fungi

Porpidia is a genus of crustose lichens in the family Lecideaceae. Porpidia species primarily inhabit siliceous rocks, pebbles, and stonework, with rare occurrences on bark, wood, and compacted soil. The thallus, or body of the lichen, varies in appearance from thick and crusty to barely visible. It may form a continuous layer or develop cracks resulting in a segmented, areolate structure. The colour of the thallus ranges from grey and white to orange.

<i>Megalaria</i> Genus of lichen-forming fungi

Megalaria is a genus of lichen-forming fungi in the family Ramalinaceae. It contains 44 species of crustose lichens, the majority of which grow on bark.

Porpidia seakensis is a species of crustose lichen in the family Lecideaceae. It is an endolithic species, meaning it grows inside the rocks, between the grains. Found only in Alaska, it was formally described as a new species in 2020 by British lichenologist Alan Fryday. The type specimen was collected in the Hoonah-Angoon Census Area, in Glacier Bay National Park. Here it was discovered growing on granitic rock in a woodland. The lichen is only known from this area, although it is locally common. Its preferred habitat is siliceous rocks and boulders in wooded areas that are open and well lit. The specific epithet seakensis uses the letters "seak" to refer to a standard abbreviation for southeast Alaska.

Sagiolechiaceae is a small family of lichen-forming fungi in the order Ostropales. It contains two genera, Rhexophiale, and Sagiolechia, the type genus.

Buellia peregrina is a species of saxicolous (rock-dwelling), crustose lichen in the family Caliciaceae. It is found in the Namib desert in Namibia.

Schaereria porpidioides is a species of saxicolous (rock-dwelling), crustose lichen in the family Schaereriaceae. It is found in the Falkland Islands.

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Porpidia nadvornikiana is a rare species of saxicolous (rock-dwelling), crustose lichen in the family Lecideaceae. It is known to occur only in two localities, in the Czech Republic and in Spain, where it grows on serpentinite, an ultramafic rock.

<i>Myochroidea</i> Genus of lichens

Myochroidea is a genus of lichen-forming fungi of uncertain familial placement in the order Lecanorales. It has four species of grey or brown-grey crustose lichens.

Tapellaria intermedia is a little-known species of foliicolous (leaf-dwelling) crustose lichen in the family Pilocarpaceae. It occurs in Bolivia.

<i>Porpidia macrocarpa</i> Species of lichen

Porpidia macrocarpa is a species of saxicolous (rock-dwelling), crustose lichen in the family Lecideaceae.

<i>Stenhammarella</i> Single-species lichen genus

Stenhammarella is a fungal genus that contains a single species, Stenhammarella turgida, a saxicolous (rock-dwelling) crustose lichen. This lichen grows on limestone rocks in alpine environments and is found in Europe and China. It was first described in 1810 by the Swedish lichenologist Erik Acharius, the "father of lichenology". The lichen has a chalky, greyish body with distinctive reproductive structures (apothecia) that change appearance as the organism matures. Initially classified under various names and genera, it was given its own genus, Stenhammarella, in 1967. Modern genetic studies have placed it in the Lecideaceae family of fungi, revealing its close relationship to lichens in the genus Porpidia.

<i>Romjularia</i> Single-species lichen genus

Romjularia is a fungal genus in the family Lecideaceae, containing the single species Romjularia lurida, a saxicolous and terricolous squamulose lichen.

<i>Aspilidea</i> Single-species lichen genus

Aspilidea is a fungal genus of uncertain familial placement in the subclass Ostropomycetidae. It contains the single species Aspilidea myrinii, a saxicolous (rock-dwelling) crustose lichen with a circumpolar distribution.

<i>Leprantha</i> Genus of lichens

Leprantha is a fungal genus in the family Arthoniaceae. It comprises a single species, Leprantha cinereopruinosa, a corticolous (bark-dwelling), crustose lichen.

References

  1. ↑ Hyde, K.D.; Noorabadi, M.T.; Thiyagaraja, V.; He, M.Q.; Johnston, P.R.; Wijesinghe, S.N.; et al. (2024). "The 2024 Outline of Fungi and fungus-like taxa". Mycosphere. 15 (1): 5146–6239 [5255]. doi:10.5943/mycosphere/15/1/25.
  2. 1 2 3 4 5 6 7 8 9 10 Fryday, Alan M.; Götz, Anna M.; Ruprecht, Ulrike (2024). "Imsharria orangei (Ascomycota, Lecideaceae), a new genus and species, and a new species of Porpidia, from the Falkland Islands". The Lichenologist. 56 (4): 137–147. doi:10.1017/S0024282924000148.
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