''Astrochapsa sipmanii'' is a little-known species of corticolous (bark-dwelling) lichen 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 Singapore.

Taxonomy

The lichen was formally described as a new species in 2015 by Gothamie Weerakoon 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 the first author from the

Bukit Timah Nature Reserve The Bukit Timah Nature Reserve ( abbreviation: BTNR) is a nature reserve near the geographic centre of Singapore, located on the slopes of Bukit Timah Hill, the country's highest natural peak standing at a height of approximately , and parts ...

at an elevation of . It is only known to occur at the

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

. 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, either of these two meanings, each with its own set of rules: * Specific name (botany) A botanical name ...

''sipmanii'' honours Dutch lichenologist

Harrie Sipman Henricus (Harrie) Johannes Maria Sipman (born 1945) is a Dutch lichenologist. He specialises in tropical and subtropical lichens, and has authored or co-authored more than 250 scientific publications. He was the curator of the lichen herbarium ...

, "for his contributions to our knowledge of Singapore lichens".

Description

The lichen has a thin, olive-brown thallus up to in diameter, and lacks a distinct

medulla Medulla 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 ovary * Medulla of ...

. 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 ...

are more or less rounded to irregular, measuring 0.4–0.7 mm in diameter. The exposed disc is grey, and covered with a thick granular

pruina Pruinescence , or pruinosity, is a "frosted" or dusty-looking coating on top of a surface. It may also be called a pruina (plural: ''pruinae''), from the Latin word for hoarfrost. The adjectival form is pruinose . Entomology In insects, a "blo ...

Ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...

s number eight per

ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...

; they have between 3 and 5

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates transit bus, bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people ...

and measure 12–15 by 3–4

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 ...

. Analysis of the lichen using chemical analyses (

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 ...

and

high-performance thin-layer chromatography High-performance thin-layer chromatography (HPTLC) is an enhanced form of thin-layer chromatography (TLC). A number of enhancements can be made to the basic method of thin-layer chromatography to automate the different steps, to increase the r ...

) did not reveal the presence of any

lichen product Lichen products, also known as lichen substances, are organic compounds produced by a lichen. Specifically, they are secondary metabolites. Lichen products are represented in several different chemical classes, including terpenoids, orcinol de ...

s. ''

Astrochapsa astroidea ''Astrochapsa'' is a genus of lichen-forming fungi in the subfamily Graphidoideae of the family Graphidaceae. It has 28 species. The genus was circumscribed by Sittiporn Parnmen, Robert Lücking, and H. Thorsten Lumbsch in 2012, with '' Astrocha ...

'', the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

of genus ''

Astrochapsa ''Astrochapsa'' is a genus of lichen-forming fungi in the subfamily Graphidoideae of the family Graphidaceae. It has 28 species. The genus was circumscribed by Sittiporn Parnmen, Robert Lücking, and H. Thorsten Lumbsch in 2012, with '' Astrocha ...

'', is somewhat similar in appearance to ''A. sipmanii'', but that species has neither an olive-brown thallus nor the thick apothecial pruina.

References

{{Taxonbar, from=Q25358376 Graphidaceae Lichen species Lichens described in 2015 Lichens of Malesia Taxa named by Gothamie Weerakoon Taxa named by Robert Lücking