''Synarthonia leproidica'' is a species of saxicolous (rock-dwelling) and

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 order Arthoniales. Found in

Luxembourg Luxembourg ( ; lb, Lëtzebuerg ; french: link=no, Luxembourg; german: link=no, Luxemburg), officially the Grand Duchy of Luxembourg, ; french: link=no, Grand-Duché de Luxembourg ; german: link=no, Großherzogtum Luxemburg is a small lan ...

, it was formally described as a new species in 2020 by lichenologists Damien Ertz,

André Aptroot André Aptroot (Heemskerk, 1961) is a Dutch mycologist and lichenologist. In 1993 he did his PhD at the University of Utrecht under the supervision of Robbert Gradstein (nl). His dissertation was titled "Systematic studies on pyrenocarpous li ...

, and Paul Diederich. 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 in the Vallée du Lellgerbaach ( Lellingen) at an elevation of . Here the lichen was found on a siliceous wall at the edge of a forest path in an

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

- hornbeam forest. It has a pale greyish crust-like thallus with dark brown/violet tinges. It has a ''leproid'' growth form, meaning that it looks like it is made of granules; 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 ...

refers to this characteristic. The thallus forms patches that are about 0.5–5 mm in diameter, although neighbouring patches can coalesce to form larger patches up to in diameter. ''Synarthonia leproidica'' contains

psoromic acid Psoromic acid is a β-orcinol depsidone with the molecular formula C18H14O8. Psoromic acid inhibits herpes simplex viruses type 1 and type 2. Furthermore, it inhibits the RabGGTase. Psoromic acid occurs in antarctic lichens A lichen ( , ) ...

, a secondary chemical that can be detected with thin-layer chromatography.

References

Arthoniomycetes Lichen species Lichens described in 2020 Lichens of Europe Taxa named by André Aptroot Taxa named by Paul Diederich {{Arthoniomycetes-stub