''Graphis marusae'' is a species of corticolous (bark-dwelling)

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

in the family

Graphidaceae The Graphidaceae are a family of lichens in the order Ostropales. Distribution and ecology The vast majority of Graphidaceae species are restricted to the tropics. Most Graphidaceae species are epiphytic (i.e. they grow only on plants). Gene ...

. It is found in a relict tropical lowland rainforest in

Veracruz Veracruz (), formally Veracruz de Ignacio de la Llave (), officially the Free and Sovereign State of Veracruz de Ignacio de la Llave ( es, Estado Libre y Soberano de Veracruz de Ignacio de la Llave), is one of the 31 states which, along with Me ...

, Mexico, growing in exposed

understory In forestry and ecology, understory (American English), or understorey (Commonwealth English The use of the English language in current and former member countries of the Commonwealth of Nations was largely inherited from British co ...

Taxonomy

The lichen-forming fungus was described as new to science in 2011 by the lichenologists Alejandrina Peña and

Robert Lücking Robert Lücking (born 1964) is a German lichenologist. He is a leading expert on foliicolous lichens–lichens that live on leaves. Life and career Born in Ulm in 1964, Lücking earned both his master's (1990) and PhD degree (1994) at the Univer ...

. The

type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

was collected by Bárcenas Peña from the

Los Tuxtlas Biosphere Reserve The Los Tuxtlas Biosphere Reserve or Biósfera Los Tuxtlas, is a biosphere reserve located in the coastal and higher elevations of the Sierra de los Tuxtlas, in Los Tuxtlas of Veracruz state, in south eastern Mexico. Ecoregion The area is notable ...

at an elevation of , where it was growing in a lowland

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfo ...

on the bark of ''

Astrocaryum mexicanum ''Astrocaryum mexicanum'', the chocho palm, cohune palm, or chapay, is a species of cocosoid palm in the family Arecaceae, native to Mexico and Central America. It is very long-lived for a palm, reaching 140 years. Local people harvest its youn ...

'' and '' Pseudolmedia oxyphyllaria''. It is characterised by its green

thallus Thallus (plural: 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. Many of these organisms ...

, its 1–5 mm-long (elongated and slit-like fruiting bodies) with grey-black labia.

Description

The

of ''Graphis marusae'' reaches up to in diameter with a thickness of 50–100

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

. The surface of the thallus is smooth, shiny, and pale greenish-grey in colour. There is no

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 initial growth stage or outer layer). In cross-section, the thallus has a (firm and tough) upper cortex, an irregular , and clusters of crystals. The

apothecia An ascocarp, or ascoma (), 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. Ascocarps are mo ...

(fruiting bodies) of ''Graphis marusae'' are (elongated and slit-like) and (curved or twisted), typically unbranched, and prominent on the surface. They measure 1–5 mm in length, 0.2–0.3 mm in width, and 0.2–0.25 mm in height. The of the apothecia is concealed, with a thick (border) that initially remains smooth but eventually becomes striate (striped). The (the part of the thallus surrounding the apothecium) is indistinct, thin, and ranges from basal to almost lateral, greenish-grey in colour. The grey-black labia (edges of the proper margin) are almost fully exposed. The (the cup-like structure around the apothecium) is completely (blackened and hardened), measuring 80–120 μm in width, and can be entire (smooth) to apically (scalloped at the top). The excipulum is basally covered by a thin layer of the thallus. The (layer beneath 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 others som ...

) is (composed of elongated, interwoven cells), 10–20 μm high, and colourless. The hymenium (spore-producing layer) is 100–150 μm high, colourless, and clear, while the (uppermost layer of the hymenium) is indistinct. The

paraphyses Paraphyses are erect sterile filament-like support structures occurring among the reproductive apparatuses of fungi, ferns, bryophytes and some thallophytes. The singular form of the word is paraphysis. In certain fungi, they are part of the fe ...

(sterile filaments among the spores) are unbranched. The

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

(spore sacs) are (spindle-shaped), measuring 90–120 by 25–35 μm. Each ascus contains 8 ascospores, which are oblong, 9–13-

septate In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatr ...

(divided by transverse septa), measuring 50–70 by 10–15 μm, and are 4–5 times as long as they are wide. The are colourless. No

secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the no ...

s were detected in ''Graphis marusae'' using

thin-layer chromatography Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. Thin-layer chromatography is performed on a sheet of an inert substrate such as glass, plastic, or aluminium foil, which is coated with a t ...

References

{{Taxonbar, from=Q18345994 marusae Lichens described in 2011 Lichen species Lichens of Mexico Taxa named by Robert Lücking