''Lepraria santosii'' is a species of

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 Stereocaulaceae. It occurs in

Tenerife Tenerife (; ; formerly spelled ''Teneriffe'') is the largest and most populous island of the Canary Islands. It is home to 43% of the total population of the archipelago. With a land area of and a population of 978,100 inhabitants as of Janu ...

, in the

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...

Taxonomy

It was formally described as a new species in 2006 by Arturo Argüello and

Ana Crespo Ana María Crespo de las Casas (born 30 March 1948, Santa Cruz de Tenerife) is a Spanish lichenologist noted for studying the phytosociology, taxonomy and floristics of Mediterranean lichens. She was awarded the 2012 Acharius Medal from the Intern ...

. The

type specimen In biology, a type is a particular wiktionary:en:specimen, 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 a ...

was collected at a road cutting in (

) at an elevation of . Here, on a shaded, north-facing slope, it was found growing on the soil over

basaltic rock Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of a ...

s. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

honours Canarian botanist Arnaldo Santos of the Botanical Garden of Puerto de la Cruz in Tenerife.

description

The

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 wer ...

of ''Lepraria santosii'' ranges in form from

crustose Crustose is a habit of some types of algae and lichens in which the organism grows tightly appressed to a substrate, forming a biological layer. ''Crustose'' adheres very closely to the substrates at all points. ''Crustose'' is found on rocks and ...

(crust-like) to somewhat

squamulose A squamulose lichen is a lichen that is composed of small, often overlapping "scales" called squamules. If they are raised from the substrate and appear leafy, the lichen may appear to be a foliose lichen, but the underside does not have a "skin ...

(scaly) to leprose (powdery or granular). Measuring about 0.2 mm thick, its colour is whitish grey to greenish grey. The granules comprising the thallus are round and 20–100

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 Unit ...

in diameter; they are surrounded by colourless, branching, projecting

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

e. The lichen does not have a medulla. The

photobiont A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.green alga The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

whose cells measure about 10–16 μm in diameter and sometimes clump together. ''Lepraria santosii'' contains several lichen products: atranorin, roccellic acid,

stictic acid Stictic acid is an aromatic organic compound, a product of secondary metabolism in some species of lichens. Stictic acid is the subject of preliminary biomedical research. Stictic acid has cytotoxic and apoptotic effects ''in vitro''. Computation ...

, and

zeorin Zeorin is a triterpene with the molecular formula C30H52O2 which occurs in many lichens A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among hypha, filaments of multiple fungus, fungi species in a mutu ...

. ''

Lepraria xerophila ''Lepraria'' is a genus of leprose crustose lichens that grows on its substrate like patches of granular, caked up, mealy dust grains.A taxonomic revision of the North American species of Lepraria s.l. that produce divaricatic acid, with notes ...

'' is similar in appearance but has a different chemistry.

References

{{Taxonbar, from=Q17387942 santosii Lichen species Lichens described in 2006 Taxa named by Ana Crespo Lichens of Macaronesia