''Malmidea volcaniana'' is a species of

corticolous This glossary of mycology is a list of definitions of terms and concepts relevant to mycology, the study of fungi. Terms in common with other fields, if repeated here, generally focus on their mycology-specific meaning. Related terms can be found ...

(bark-dwelling),

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

in the family

Malmideaceae Malmideaceae is a family of crustose and corticolous lichens in the order Lecanorales. It contains eight genera and about 70 species. Taxonomy Malmideaceae was created in 2011 to accommodate a group of species, formerly placed in genus '' Malc ...

. It is found in Venezuela. A major characteristic of the species is the coralloid (

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

-shaped) clumps of

isidia An isidium (plural: isidia) is a tiny, wart- or finger-like outgrowth on the thallus surface of certain lichen species. It is one of two principal types of vegetative reproduction, vegetative reproductive structures in lichens, the other being ...

-like outgrowths on the

thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...

surface.

Taxonomy

The lichen was

formally described A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

as a new species in 2021 by the German lichenologist

Klaus Kalb Klaus Kalb (born 1942) is a German lichenologist and an authority on tropical lichens. Born in Nuremberg, he studied at the University of Erlangen–Nuremberg before pursuing a career that significantly advanced the field of lichenology, parti ...

. The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

was collected from the

Cerro El Volcán Cerro El Volcán (sometimes written as "El Picacho Volcano") is the highest peak in El Hatillo Municipality, which is part of the metropolitan area of the Metropolitan District of Caracas in northern Venezuela, South America South Americ ...

( Miranda), at an altitude of . The

species epithet Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In Taxonomy (biology), taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany) ...

refers to the type locality.

Description

''Malmidea volcaniana'' is a

with a continuous

that ranges in thickness from 20 to 40

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

. The thallus is characterised by formations that are more or less spherical and coalesce with age, forming clumps of thin,

-like outgrowths. These formations are dull and vary in colour from greenish grey to ash-grey. The species has

soralia Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or g ...

that are more or less , measuring around 0.01 mm in diameter and intense orange-yellow in colour, emerging from warts that break off at the tips. These soralia react K+ (purple) and P+ (wine-red) to chemical spot tests. The medulla of the and thallus is orange-yellow and also reacts to potassium hydroxide (K+ purple) and P+ (wine-red). The of this species is , with cells measuring 6–8 μm in diameter.

Apothecia An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. As ...

in ''Malmidea volcaniana'' are

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

and rounded, measuring between 0.3 and 0.8 mm in diameter and 0.2–0.3 mm in height. The apothecial are initially flat but become distinctly convex with age, coloured beige to chocolate-brown. The is of the ''granifera''-type, , and ranges in colour from whitish and cream-coloured to greyish, typically paler than the disc. The is

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

(translucent), while the medullary excipulum is orange-yellow and filled with opaque, orange-yellow

anthraquinone Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic hydrocarbon, aromatic organic compound with formula . Several isomers exist but these terms usually refer to 9,10-anthraquinone (IUPAC: 9,10-dioxoanthracene) wherein th ...

s, only partially dissolving in a solution of

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

, with a K+ (golden-yellow to golden-orange) reaction. The is around 20 μm high and light brown. The centrally located is 75–85 μm high, narrowing towards the margin, and is dark brown in colour, not reacting to potassium hydroxide (K−). The is indistinct, and the

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...

measures 75–100 μm in height and is hyaline. The asci of ''Malmidea volcaniana'' are 50–60 μm by 15–20 μm in size, and each contains 6–8 . These spores lack

septa SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...

and are broadly

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

with equally thickened walls and a of 1–1.5 μm. The spores measure 11–17 by 7–10 μm. Chemically, this species contains

emodin Emodin (6-methyl-1,3,8-trihydroxyanthraquinone) is an organic compound. Classified as an anthraquinone, it can be isolated from rhubarb, buckthorn, and Japanese knotweed ('' Reynoutria japonica'' syn. ''Polygonum cuspidatum''). Emodin is part ...

and emodic acid as major or somewhat major

lichen product Lichen products, also known as lichen substances, are organic compounds produced by a lichen. Specifically, they are secondary metabolites. Lichen products are represented in several different chemical classes, including terpenoids, orcinol deri ...

atranorin Atranorin is a chemical substance produced by some species of lichen. It is a secondary metabolite belonging to a group of compounds known as depsides. Atranorin has analgesic, anti-inflammatory, antibacterial, antifungal, cytotoxic, antioxidant, ...

and emodin bisanthrone as minor components, and some unknown xantholepinones.

References

{{Taxonbar, from=Q123983880 volcaniana Lichen species Lichens described in 2021 Lichens of Venezuela Taxa named by Klaus Kalb