''Malmidea rhodopisoides'' 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 Brazil.

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 by the author from (

São Paulo São Paulo (; ; Portuguese for 'Paul the Apostle, Saint Paul') is the capital of the São Paulo (state), state of São Paulo, as well as the List of cities in Brazil by population, most populous city in Brazil, the List of largest cities in the ...

) at an elevation 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) ...

alludes to its resemblance to '' Malmidea rhodopis''.

Description

''Malmidea rhodopisoides'' is a

with a

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 ...

thickness of 20–40

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 ...

. It is composed 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 forming clumps that densely cover an orange-red

prothallus A prothallus, or prothallium, (from Latin ''pro'' = forwards and Greek ''θαλλος'' (''thallos'') = twig) is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young ...

. The thallus surface is dull, showing shades of grey to greenish grey, which turns orange-red when the cortex is abraded. Its

medulla Medulla (Latin for "marrow") or medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ...

is also orange-red and has a K+ (red) chemical

spot test Spot analysis, spot test analysis, or a spot test is a chemical test, a simple and efficient technique where analytic assays are executed in only one, or a few drops, of a chemical solution, preferably in a great piece of filter paper, without usin ...

reaction. The 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 ...

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 0.7–1.5 mm in diameter and 0.4–0.5 mm in height. The apothecial is initially flat but becomes slightly convex, ranging in colour from beige to dark brown. The margin around the disc is about 0.1 mm thick, bulging, and elevated above the disc, typically orange-red and occasionally partly blackish. The of ''Malmidea rhodopisoides'' is of the ''piperis''-type,

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) at the periphery, with the inner part containing

hydrophobic In chemistry, hydrophobicity is the chemical property of a molecule (called a hydrophobe) that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thu ...

granules of norsolorinic acid. The is approximately 20 μm high and varies from hyaline to light brown. The is relatively tall, ranging from 200 to 400 μm, reddish to dark brown in colour, and does not react to potassium hydroxide (K−). The of the species is either indistinct or slightly granular, while 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 ...

is hyaline and stands 70–80 μm high. Asci within this species measure 60–70 by 20–25 μm, each containing 6–8 ascospores. These spores 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 ...

to , 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 ...

(internal partitions), with a uniformly thickened wall and a approximately 1 μm thick. The size of the spores ranges between 15 and 20 by 9–12 μm. Chemically, ''Malmidea rhodopisoides'' is characterized by a major presence of norsolorinic acid and a lack of

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, ...

Similar species

''Malmidea rhodopisoides'' has characteristics that position it between '' Malmidea rhodopis'' and '' Malmidea isidiifera''. ''M. rhodopis'' consistently has a smooth and often corticate thallus and is further distinguished by smaller spores measuring 9–15 by 5–8 μm. In contrast to ''M. isidiifera'', which lacks norsolorinic acid in the inner layer of its structural excipulum and features a thallus covered with elongated, non-granular outgrowths (isidia), ''Malmidea rhodopisoides'' has traits that are intermediate between these two species.

References

{{Taxonbar, from=Q123983877 rhodopisoides Lichen species Lichens described in 2021 Lichens of Brazil Taxa named by Klaus Kalb