''Xanthoparmelia serusiauxii'' is a species of

foliose lichen Foliose lichen is one of the morphological classes of lichens, which are complex organisms that arise from the symbiotic relationship between fungi and a photosynthetic partner, typically algae. This partnership allows lichen to live in diverse ...

in the family

Parmeliaceae The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: '' Xanthoparmelia'' ( 822 ...

. Found in

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

, it was formally described as a new species in 1986 by American lichenologist

Mason Hale Mason Ellsworth Hale, Jr. (September 23, 1929 – April 23, 1990) was one of the most prolific lichenologists of the 20th century. Many of his scholarly articles focused on the taxonomy of the family Parmeliaceae. Hale was one of the first liche ...

. 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 by Hale from the Laguneberg Mountains, southeast of

Cape Cross Cape Cross (Afrikaans: ''Kaap Kruis''; German: ''Kreuzkap''; Portuguese: ''Cabo da Cruz'') is a headland in the South Atlantic in Skeleton Coast, western Namibia. History In 1484, Portuguese navigator and explorer Diogo Cão was ordered by Ki ...

. There, it is common on

dolerite Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grained ...

boulders and small, flat pebbles. 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

Emmanuël Sérusiaux Emmanuël Sérusiaux (born 3 October 1953) is a Belgian lichenologist. His career, spanning more than four decades, has combined both lichenology research and political aspects of nature conservation. He spent several periods working as a res ...

, who, according to Hale, "was the first lichenologist to collect this unusual lichen in Namibia". The lichen has a foliose thallus measuring wide with a dull greenish-yellow colour that tends to blacken in the centre with age. The lobes that comprise the thallus are 1–2 mm wide, and have black rims.

Isidia An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting o ...

and soredia are absent from the thallus. The medulla is particularly thick and soft. The few rhizines it has are coarse, black, and measure 0.3–0.5 mm long. ''Xanthoparmelia serusiauxii'' contains the

secondary compounds 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 norma ...

lecanoric acid Lecanoric acid is a chemical produced by several species of lichen.ubChem - Lecanoric acid"> Lecanoric acid is classified as a polyphenol and a didepside and it functions as an antioxidant. The acid is named after the lichen ''Lecanora''. The acid ...

and

usnic acid Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species with the formula C18H16O7. It was first isolated by German scientist W. Knop in 1844 and first synthesized between 1933-1937 by Curd and Robertson. Usnic a ...

. Other ''

Xanthoparmelia ''Xanthoparmelia'' (commonly known as green rock shields or rock-shield lichens) is a genus of foliose lichen in the family Parmeliaceae.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ''Xanthoparmelia'' is syn ...

'' species that commonly occur in the same area are '' X. evernica'' and '' X. lagunebergensis''. In a study of the lichen growth form distributions within the lichen fields of the Central Namib desert, ''Xanthoparmelia serusiauxii'' was found to occur in areas subject to the abrasive action of strong winds carrying sand, and subject to more severe drought due to less frequent occurrence of fog.

References

{{Taxonbar, from=Q10721637 serusiauxii Lichen species Lichens of Namibia Lichens described in 1986 Taxa named by Mason Hale

See also

References