Myochroidea

Last updated

Myochroidea
Myochroidea rufofusca.jpg
Myochroidea rufofusca
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Genus: Myochroidea
Printzen, T.Sprib. & Tønsberg (2008)
Type species
Myochroidea rufofusca
(Anzi) Printzen, T.Sprib. & Tønsberg (2008)
Species

M. leprosula
M. minutula
M. porphyrospoda
M. rufofusca

Contents

Myochroidea is a genus of lichen-forming fungi of uncertain familial placement in the order Lecanorales. [1] It has four species of grey or brown-grey crustose lichens. [2]

Taxonomy

The genus was proposed in 2008 by the lichenologists Christian Printzen, Toby Spribille, and Tor Tønsberg, with Myochroidea rufofusca assigned as the type species. [3] This lichen was first described as Biatora rufo-fusca by Martino Anzi in 1860. [4] The name Myochroidea is derived from the Greek word myochrous, which translates to "mouse-coloured." This naming is inspired by the characteristic grey or brown-grey colour of the lichen's body (thallus), reminiscent of the hues found in a mouse's fur. [3]

Description

The thallus of Myochroidea is crust-like and not clearly defined at its edges. It has a texture that can range from wart-like clusters to small, granule -like structures, especially noted in the species M. minutula. These granules are similar in appearance to tiny, angular cysts. The clusters ( areoles ) can vary in shape from slightly to prominently rounded, sometimes even resembling coral in their complexity. The surface of these lichens is non-glossy, with hues from mouse grey to greyish brown or olive brown, and harbours a trebouxioid (green algal) photobiont. [3]

The reproductive structures (apothecia) of Myochroidea are reddish to blackish brown, and occasionally ochre, in colour. These structures are seated directly on the thallus and may range from flat to significantly rounded, maintaining a matte or slightly shiny appearance. These parts are either not covered in a powdery coating ( pruina ) or have such a coating so fine that it's only noticeable when moist. The edges of the apothecia are typically slightly raised compared to the central disc , though in older structures, the edges may not be as distinct. The supporting tissue ( exciple ) surrounding the reproductive discs is either colourless or a pale orange-brown, with the outermost layers blending in colour with the layer above the reproductive cells ( epihymenium ), composed of strongly gel-like, interweaving and branching fungal filaments. These filaments may be interspersed with small, colourless to pale yellow granules. The underlying tissue layers ( hypothecium , subhymenium , and hymenium) are colourless, while the epihymenium may be a pale ochre to brown shade. The filaments (paraphyses) are branched and fuse together, with their tips often brown and slightly enlarged. The spore-producing structures (asci) contain eight spores each and react to iodine by turning dark blue. The spores themselves are simple in form, colourless, and range from spindle-shaped to broadly elliptical. [3]

The structures typically responsible for asexual reproduction (pycnidia) have not been observed in this genus. Chemically, Myochroidea lichens may contain fatty acids, lobaric acid, and xanthones, though some species do not produce any detectable secondary metabolites. [3]

Similar genera

Myochroidea shows a superficial resemblance to the genera Biatora and Japewiella . Despite these surface similarities, these three genera can be distinguished from one another by differences in the structure of their spore-producing sacs (ascus type) and the tissue surrounding the reproductive structures (excipular anatomy). In Myochroidea, the exciple is characterised by densely interwoven fungal threads (hyphae) that have slightly thickened and pigmented ends. Contrastingly, in both Biatora and Japewiella, the hyphae within the exciple are set within a gel-like substance, a feature that is particularly prominent in Japewiella. Moreover, the presence of thickened and pigmented hyphae at the tips, as seen in Myochroidea, is not observed in Biatora. [3]

Additionally, Myochroidea shares the Micarea-type ascus with both Helocarpon and the more recently described Xyleborus , according to Harris and Ladd's 2007 publication. However, Helocarpon is distinct due to its carbonised underlayer (hypothecium) and surrounding tissue (exciple), as well as its lack of thickening at the tips of the excipular hyphae. On the other hand, Xyleborus sets itself apart with a gelatinous exciple that features radiating, lightly branched hyphae and the unique presence of spore-producing structures ( sporodochia ). [3]

Species

Related Research Articles

<i>Collema</i> Genus of lichens

Collema is a genus of lichens in the family Collemataceae. The photobiont is the cyanobacterium genus Nostoc. Species in this genus typically grow on nutrient-rich bark or somewhat siliceous or calcareous rocks in humid environments.

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

Scytinium is a genus of lichen-forming fungi in the family Collemataceae. It has 49 species. These lichens are typically found on basic rocks, soil, and trees, occasionally in association with mosses. Despite the morphological and ecological diversity within Scytinium, its species share similar ascospore features, such as shape and septation, as well as a small to medium-sized thallus with at least a partial cortex.

Biatora pacifica is a species of corticolous (bark-dwelling), crustose lichen in the family Ramalinaceae. It is found in Russia, Japan, and South Korea, where it grows along the Pacific coast. It inhabits the bark of a variety of coniferous and deciduous plants.

Pertusaria albineoides is a species of corticolous (bark-dwelling), crustose lichen in the family Pertusariaceae. Found on the Galápagos Islands, it was formally described as a new species in 2015 by Frank Bungartz, A.W.Archer, Alba Yánez-Ayabaca, and John Elix. The type specimen was collected on Alcedo Volcano at an altitude of 1,089 m (3,573 ft), where it was found growing on a partially shaded, rain- and wind-exposed trunk of Scalesia microcephala. The species epithet refers to the similarity to the species Pertusaria albinea, from which it differs by having thin-walled ellipsoid-shaped ascospores that are longer and narrower.

<i>Biatora pontica</i> Species of lichen

Biatora pontica is a species of corticolous (bark-dwelling), leprose lichen in the family Ramalinaceae. It is a widely distributed species, having been recorded in Africa, Asia, Europe, and North America.

Calogaya orientalis is a species of corticolous (bark-dwelling) and muscicolous lichen (moss-dwelling), crustose lichen in the family Teloschistaceae. It is found in arid steppe and desert habitats in Northwestern China, Iran, and Turkey. The thallus of this lichen is reduced, similar to species in the genus Athallia.

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.

Megalospora austropacifica is a species of corticolous (bark-dwelling), crustose lichen in the family Megalosporaceae. It is found on the islands of Taveuni and Viti Levu in Fiji. It has a yellowish grey to whitish grey, glossy thallus that is thick and may appear slightly wrinkled or smooth, often with irregular cracks and small papillae containing conidiomata, but lacking isidia and soredia. Its apothecia are circular, up to 4.5 mm in diameter, with the disc evolving from concave to slightly convex and coloured from orange-brown to red-brown, surrounded by a thick, prominent margin.

Placolecis kunmingensis is a species of saxicolous (rock-dwelling), crustose lichen in the family Catillariaceae. It is found in Yunnan, China. The lichen is characterised by a thallus that is areolate to squamulose in its centre, forming irregular patches or clumps 10–50 mm wide, as well as its ellipsoid or spherical ascospores with slightly thickened wall.

Malmidea leucopiperis is a species of corticolous (bark-dwelling), crustose lichen in the family Malmideaceae. It is found in Brazil.

Buellia lordhowensis is a little-known saxicolous (rock-dwelling), crustose lichen species in the family Caliciaceae, first described in 2020. It is only known to occur on Lord Howe Island, Australia.

Amandinea pilbarensis is a little-known species of crustose lichen in the family Physciaceae, First described in 2020, it is found in Australia. It is similar to Amandinea polyxanthonica, but can be distinguished by its smaller ascospores and the presence of calcium oxalate and thiophanic acid in the medulla.

<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.

<i>Glaucomaria</i> Genus of lichens

Glaucomaria is a genus of lichen-forming fungi in the family Lecanoraceae. It has seven species. The genus was circumscribed by Maurice Choisy in 1929. It contains crustose lichens formerly placed in the Lecanora rupicola species complex as defined by several previous authors.

<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.

<i>Sucioplaca</i> Genus of lichen

Sucioplaca is a single-species fungal genus in the family Teloschistaceae. It contains Sucioplaca diplacia, a saxicolous (rock-dwelling) crustose lichen. It is common and widely distributed in the Caribbean, Central America, and the Galápagos Islands, where it grows on coastal rocks.

Buellia stellulata, commonly known as the disc lichen) is a species of crustose lichen that is widely distributed throughout the Northern Hemisphere.

Buellia bahiana is a crustose-type lichen species that frequently grows on the bark and wood of trees found in coastal and inland forest habitats. This lichen species exhibits a broad geographic distribution, being documented in various pantropical and subtropical regions around the world. Specific areas where Buellia bahiana has been recorded include parts of Australia, Africa, North America, Central America, South America, and several Pacific Island chains.

References

  1. ↑ "Myochroidea". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 5 April 2024.
  2. ↑ Wijayawardene, N.N.; Hyde, K.D.; Dai, D.Q.; Sánchez-García, M.; Goto, B.T.; Saxena, R.K.; et al. (2022). "Outline of Fungi and fungus-like taxa – 2021". Mycosphere. 13 (1): 53–453 [153]. doi:10.5943/mycosphere/13/1/2.
  3. 1 2 3 4 5 6 7 Printzen, Christian; Spribille, Toby; Tønsberg, Tor (2008). "Myochroidea, a new genus of corticolous, crustose lichens to accommodate the Lecidea leprosula group". The Lichenologist. 40 (3): 195–207. doi:10.1017/S0024282908007639.
  4. ↑ Anzi, M. (1860). Catalogus lichenum quos in provincia sondriensi et circa Novum-Comum collegit et in ordinem systematicum digessit (in Latin). C. Franchi. p. 76.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.