''Verrucaria ahtii'' is a species of

saxicolous A saxicolous lichen is a lichen that grows on rock. The prefix "sax" from the Latin means "rock" or "stone". Characteristics Saxicolous lichens exhibit very slow growth rates. They may develop on rock substrates for long periods of time, give ...

(rock-dwelling)

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

Verrucariaceae The Verrucariaceae are a family of mostly lichenised fungi in the order Verrucariales. The lichen-forming species, which comprise the vast majority of the family, have a wide variety of thallus forms, and include crustose (crust-like), foliose ( ...

. It is found in Finland, Lithuania, Russia, and Switzerland, where it occurs on

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an adje ...

pebbles.

Taxonomy

The lichen was formally described as a new species in 2017 by Juha Pykälä, Annina Launis, and Leena Myllys. 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 the first author in

Lohja Lohja (; sv, Lojo) is a city and municipality in the Uusimaa region of Finland. The city has a population of 47,518 (2017), and it covers an area of of which , or 8.3 percent, is water. The population density of Lohja is . The municipality is ...

(

Southwest Finland Southwest Finland, calqued as Finland Proper ( fi, Varsinais-Suomi ; sv, Egentliga Finland), is a region in the southwest of Finland. It borders the regions of Satakunta, Pirkanmaa, Tavastia Proper (Kanta-Häme), Uusimaa, and Åland. The regi ...

) on a high road bank northwest of a

lime Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...

processing factory; there it was found growing on a pebbles that may have been enriched by

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

-rich dust. The species epithet honours Finnish lichenologist

Teuvo Ahti Teuvo ("Ted") Tapio Ahti (born 1934) is a Finnish botanist and lichenologist. He has had a long career at the University of Helsinki that started in 1963, and then following his retirement in 1997, at the Botanical Museum of the Finnish Museum ...

, "for his major contributions to lichenology". The type specimen is kept in the collections of the mycological

herbaria A herbarium (plural: herbaria) is a collection of preserved plant specimens and associated data used for scientific study. The specimens may be whole plants or plant parts; these will usually be in dried form mounted on a sheet of paper (called ...

of the Botanical Museum of the

Finnish Museum of Natural History The Finnish Museum of Natural History ( fi, Luonnontieteellinen keskusmuseo, sv, Naturhistoriska centralmuseet), established in 1988, is a research institution under the University of Helsinki in Finland, based in Helsinki, Finland. It is a natur ...

Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analysis of

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

s from the

internal transcribed spacer Internal transcribed spacer (ITS) is the spacer DNA situated between the small-subunit ribosomal RNA (rRNA) and large-subunit rRNA genes in the chromosome or the corresponding transcribed region in the polycistronic rRNA precursor transcript. I ...

regions shows that ''Verrucaria ahtii'' is closely related to '' V. vitikainenii''.

Description

The crust-like

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 ...

''Verrucaria ahtii'' is usually from medium brown to dark grey (rarely, it is grey), and has a flake-like consistency. It has a medium- to dark-brown

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 ...

that is often inconspicuous. The

perithecia 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 partly immersed in the thallus, measure 0.15–0.32 mm in diameter, and have a dark, flat, inconspicuous

ostiole An ''ostiole'' is a small hole or opening through which algae or fungi release their mature spores. The word is a diminutive of "ostium", "opening". The term is also used in higher plants, for example to denote the opening of the involuted ...

(pore). The exciple (the ring-shaped tissue layer surrounding 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 some ...

) measures 0.16–0.32 mm and has a dark brown wall about 13–18 μm thick.

Alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mi ...

l cells are 5–11 μm wide.

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 or s ...

s are 20.6–25.5 by 10.2–12.4 μm and lack a perispore (a colorless, often gelatinous enveloping layer).

Habitat and distribution

''Verrucaria ahtii'' grows on

pebbles, and on

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

pebbles that have been enriched with calcareous dust. It prefers sunny habitats, and has been recorded from south-facing rock walls in lime quarries. The lichen was originally known to occur in Finland, Lithuania, and Russia. In 2018, it was recorded from Switzerland, where it was found growing on calcareous

plaster Plaster is a building material used for the protective or decorative coating of walls and ceilings and for Molding (decorative), moulding and casting decorative elements. In English, "plaster" usually means a material used for the interiors of ...

on a humid and shaded wall. The Lithuanian and Russian collections were incorrectly reported as '' Verrucaria invenusta''.

References

{{Taxonbar, from=Q108472101 ahtii Lichen species Lichens described in 2017 Lichens of Central Europe Lichens of Eastern Europe Lichens of Northern Europe

Taxonomy

Description

Habitat and distribution

See also

References