Auriculora

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Auriculora
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Family: Ramalinaceae
Genus: Auriculora
Kalb (1988)
Species:
A. byssomorpha
Binomial name
Auriculora byssomorpha
(Nyl.) Kalb (1988)

Auriculora is a fungal genus in the family Ramalinaceae. [1] [2] It comprises the single species Auriculora byssomorpha, a tropical crustose lichen. Both the genus and its species were described in 1988 by the German lichenologist Klaus Kalb. The main characteristic of Auriculora is the ear-like appendages at the margins of the apothecia (fruiting bodies).

Contents

Description

Auriculora is characterised by a crustose, cortex -lacking thallus containing green algae of the genus Protococcus . [3] The thallus is byssoid to granular and may be fringed by a well-developed filamentous prothallus . It shows distinct zonation, with a byssoid basal layer of loosely interwoven, thick-walled hyphae and a more compact upper layer enclosing the photobiont . The thallus occasionally develops two separate algal layers. [4] The ascomata (fruiting bodies) are rounded, thinly marginate or unmarginate, with black, non-pruinose discs covered by a hyphose layer. This layer eventually peels away, leaving an amphithecium that resembles an ear-shaped structure, which inspired the genus name. [3]

The pycnidia are patelliform (shaped like a small, shallow dish) and semi- immersed , with a dark olive-brown wall that does not react to KOH. The conidiophores are simple or slightly branched, producing rod-like conidia that measure about 10  μm in length. [3] The asci are club-shaped ( clavate ), long-cylindrical, eight-spored, and similar in structure to those found in the family Lecanoraceae. The outer wall layer and apical ring of the asci are strongly amyloid. Ascospores are hyaline, fusiform , and transversely three-septate. Paraphyses are simple (unbranched), septate, approximately 2 μm thick, and only slightly or not at all thickened at their tips. The hypothecium is dark brown, and the amphithecium is composed of radiating, cartilage-like hyphae with an ochre hue. [3]

Chemical analysis of A. byssomorpha reveals a complex secondary metabolite profile. Thin-layer chromatography studies have identified five distinct compounds: two uncharacterised substances and three triterpenes. These compounds manifest as brown crystals that accumulate on the hyphal walls throughout both the thallus and generative tissues, contributing to the lichen's characteristic dark pigmentation. The crystals are particularly dense in the upper thallus layer, though absent from the bright rim where hyphae are adglutinated at the surface. [4]

Development

Auriculora byssomorpha has a unique developmental pattern in its fruiting bodies that distinguishes it from all other known lichenised fungi. The apothecia begin development with a dark-pigmented generative tissue surrounding spirally coiled ascogonia . This develops into a compact, globose structure with a lighter-coloured, gelatinous centre where ascogenous hyphae accumulate in the upper portion. [4]

The initial hymenium develops in a gymnocarpous manner (openly exposed), with the first paraphyses and asci pushing aside the dark mantle layer. However, what makes Auriculora remarkable is its subsequent development: new hymenia repeatedly form beneath older ones within the subhymenial layer, a pattern not observed in other lichens. Each new hymenium typically develops first at one side beneath the older one, eventually forming a complete new layer except at the outermost margin. [4]

As new hymenia develop, they are usually smaller than their predecessors and do not entirely replace them. The older hymenial tissue often becomes turned backward into an inverse position, with portions remaining attached to the apothecial margin or disc. These remnants form distinctive ear-like appendages (which inspired the genus name) or create superimposed layers of tissue. In mature specimens, these remnants may form a sheath around the apothecial margin and disc. The regenerative capacity of the apothecia appears to decrease with age, as successively formed hymenia become progressively smaller. In older specimens, the remnants of disintegrating marginal tissues become correspondingly larger, eventually forming an outer marginal sheath and an inner ring around the diminishing disc. [4]

This pattern of repeated endogenous development represents a unique form of secondary hemiangiocarpy, where the covering layer derives from hymenial/subhymenial tissue rather than from vegetative or generative tissue as in other lichen groups. This developmental pattern is considered a defining characteristic of the genus and sets it apart from all other known lichenised ascomycetes. [4]

Habitat and distribution

Auriculora byssomorpha was originally described from collections made in Brazil. Since then, the lichen has also been reported from Kenya, [5] Tanzania, [4] and Costa Rica. [6]

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

Ochrolechia is the sole genus in the fungal family Ochrolechiaceae. It comprises about 40 species of crustose lichens. These lichens typically form uneven, often thick, crust-like growths on various surfaces and are characterised by their white to pale grey thalli, which may have a greenish tint. The genus has a long evolutionary history, with fossils dating back to the Paleogene period, about 34 million years ago. Ochrolechia species have disc-like apothecia, which are usually yellowish or brownish-pink and often covered with a fine white powdery coating. The genus is widely distributed and includes both common and rare species, with some found in extreme environments such as arctic and alpine regions. Ochrolechia lichens produce diverse secondary metabolites, including orcinol depsides, depsidones, and xanthones.

Lithoglypha is a fungal genus in the family Acarosporaceae. It is monotypic, containing the single species Lithoglypha aggregata, a saxicolous (rock-dwelling), crustose lichen found in South Africa.

<i>Buellia</i> Genus of lichens

Buellia is a genus of mostly lichen-forming fungi in the family Caliciaceae. The fungi are usually part of a crustose lichen. In this case, the lichen species is given the same name as the fungus. But members may also grow as parasites on lichens (lichenicolous). The algae in the lichen is always a member of the genus Trebouxia.

<i>Arthonia</i> Genus of lichens

Arthonia is a genus of lichens in the family Arthoniaceae. It was circumscribed by Swedish botanist Erik Acharius in 1806.

<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>Lathagrium</i> Genus of lichen

Lathagrium is a genus of lichen-forming fungi in the family Collemataceae. It has 10 species of gelatinous lichens. Species in this genus typically grow on calcareous rocks, often amidst mosses, but can also be found on siliceous or serpentine rocks, mortar, or soil.

<i>Roccellinastrum</i> Genus of fungi

Roccellinastrum is a genus of lichen-forming fungi in the family Pilocarpaceae. It has seven species.

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

Gyrotrema papillatum is a little-known species of corticolous (bark-dwelling), crustose lichen in the family Harpidiaceae. It is known from a single collection in a lowland rainforest region of Costa Rica.

Lecidea lygommella is a species of saxicolous (rock-dwelling), crustose lichen in the family Lecideaceae. It spreads up to 7 cm wide with a thin thallus varying in colour from whitish and pale grey to rusty red-brown, featuring areolate surfaces with irregularly shaped areoles. Its fruiting bodies range from slightly embedded to sitting atop the thallus and black, flat to slightly convex apothecial discs. Unlike its lookalike Lecidea lygomma, L. lygommella does not produce any secondary chemicals. It is found in New South Wales and Victoria, Australia, where it grows on rocks in alpine areas.

<i>Flavoplaca oasis</i> Species of lichen

Flavoplaca oasis is a species of saxicolous (rock-dwelling), crustose lichen in the family Teloschistaceae. It is widely distributed across Europe, and has been reported in Western Asia, China, and North Africa.

Nitidochapsa is a genus of lichen-forming fungi in the family Graphidaceae. It has five species of corticolous (bark-dwelling), crustose lichens.

<i>Glaucomaria carpinea</i> Species of lichen

Glaucomaria carpinea is a species of corticolous (bark-dwelling), crustose lichen in the family Lecanoraceae. It is a widely distributed species.

Buellia subalbula is a species of saxicolous (rock-dwelling), crustose lichen in the family Caliciaceae. It occurs in coastal southern Africa, South America, and Australia, where it grows on calcareous rocks.

<i>Porpidinia</i> Genus of lichens

Porpidinia is a genus of lichen-forming fungi in the family Lecideaceae. It has two species of saxicolous (rock-dwelling) lichens. The type species of the genus, Porpidinia tumidula, thrives in a variety of settings from coastal to mountainous areas, primarily on lime-rich rocks, and is widely spread across southern to northern Europe, northern Africa, parts of Asia, and New Zealand. Meanwhile, Porpidinia brevispora is more regionally confined, found specifically in the Sikhote-Alin range in the Russian Far East, favouring carbonate rocks at lower altitudes.

Megaloblastenia is a genus of crustose lichen-forming fungi in the family Megalosporaceae, comprising three species. Proposed by Dutch lichenologist Harrie Sipman in 1983, the genus is characterised by its thick, ecorticate thallus ranging from pale whitish-grey to yellowish, and its disc-like fruiting bodies (apothecia) that can be biatorine or lecideine. Megaloblastenia lichens form a symbiotic relationship with Dictyochloropsis algae, produce hyaline, bicellular ascospores with polaribilocular structure, and contain chemical compounds such as zeorin, pannarin, or usnic acid. Found in Australasia and South America, these lichens typically grow as epiphytes on trees in moist forests within temperate to tropical oceanic climates.

Pseudopeltula is a genus of lichen-forming fungi in the family Gloeoheppiaceae. Established in 1995 by the lichenologist Aino Henssen, the genus currently includes four recognised species. These small cyanolichens are characterised by their squamulose (scaly) to peltate (shield-shaped) thalli, which lack a lower cortex and are attached to the substrate by rhizines. A key feature of Pseudopeltula is its complex apothecia, which have hymenia that often become divided by sterile tissue as they mature. The genus is primarily found in arid and semi-arid regions of North America, Mexico, and the Caribbean, where species typically grow on soil, rock, or thin soil over rock, often forming part of biological soil crusts in desert environments.

Parallopsora is a small genus of lichen-forming fungi in the family Ramalinaceae. Established in 2018, the genus contains three species that were previously classified under a related genus, Phyllopsora. These lichens form small, scale-like growths that overlap like roof tiles and typically appear pale green to bluish-green in colour. They reproduce through both small brown fruiting bodies and sometimes through powdery structures on their surface. The species are known to grow in tropical rainforests, particularly in Brazil, Peru and Cuba.

References

  1. ↑ "Auriculora". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 12 December 2024.
  2. ↑ 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 [5254]. doi:10.5943/mycosphere/15/1/25.
  3. 1 2 3 4 Kalb, K. 1988. Lichenes Neotropici. 10:401–450
  4. 1 2 3 4 5 6 7 Henssen, A.; Titze, A. (1990). "Auriculora byssomorpha, a tropical lichen with a remarkable developmental morphology". Botanica Acta. 103 (2): 131–139. doi:10.1111/j.1438-8677.1990.tb00138.x.
  5. ↑ Kirika, Paul; Mugambi, George; Lücking, Robert; Lumbsch, H. Thorsten (2012). "New records of lichen-forming fungi from Kenya". Journal of East African Natural History. 101 (1): 73–98. doi:10.2982/028.101.0105.
  6. ↑ Mardones, Melissa; Umañan Tenorio, Loengrin; Granados Montero, María del Milagro; Mata Hidalgo, Milagro; Ruiz-Boyer, Armando; Piepenbring, Meike; Minter, David; Coto-López, Cristofer; Carranza Velásquez, Julieta (2024). "The first annotated checklist of Costa Rican fungi". Funga Latina. 2. doi:10.5281/ZENODO.14165034.
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