''Verrucaria oulankaensis'' is a rare species of saxicolous (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 north-eastern Finland, 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 ...

rocks on river shores.

Taxonomy

The lichen was formally described as a new species in 2017 by Juha Pykälä 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 along the shore of the Oulankajoki river in

Oulanka National Park Oulanka National Park ( fi, Oulangan kansallispuisto) is a national park in the Northern Ostrobothnia and Lapland regions of Finland, covering . The park was established in 1956 and was expanded in 1982 and 1989. It borders the Paanajärvi Nati ...

(

Koillismaa Koillismaa ("North-East Finland") is a subdivision of Northern Ostrobothnia and one of the Sub-regions of Finland since 2009. Municipalities * Kuusamo * Taivalkoski Geographic region Koillismaa is also a geographic region, which includes Kuu ...

); there, at an altitude of , it was found growing on a

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

rock outcrop jutting out from a southwest-facing rock wall. The species epithet ''oulankaensis'' refers to the predominance of collections from the Oulanka area, which the authors call "one of the lichenologically most important areas in Finland". The type specimen is kept in the collections of the mycological herbaria 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 ...

Description

The colour of 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 oulankaensis'' ranges from pale brown to brownish grey, medium brown or dark brown, and usually grey with a

pruinose 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 ...

covering. It has a 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 ...

. The perithecia are immersed in the thallus, and measure 0.12–0.27 mm in diameter, and have a dark

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) that is often inconspicuous. 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 0.15–0.25 mm and has a dark brown wall. Algal cells are 5–10 μm wide. The

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

contain eight spores and measure about 50–61 by 19–24

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 ...

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 16.2–19.3 by 7.7–9.1 μm and lack a (a colorless, often gelatinous enveloping layer).

Habitat and distribution

''Verrucaria oulankaensis'' grows on

rocks, and all collections have been made from rivers shores – a particular habitat that is rare in Finland. The lichen is known to occur only in Oulanka area of northeastern Finland. A common lichen associate in its habitat is '' Staurothele areolata''. Other rare lichens occurring in this area are '' Nephroma helveticum'' and '' Peltigera retifoveata''.

References

{{Taxonbar, from=Q108473842 oulankaensis Lichen species Lichens described in 2017 Lichens of Northern Europe

Taxonomy

Description

Habitat and distribution

See also

References