''Punctelia colombiana'' is a species of corticolous (bark-dwelling) and foliose (leafy)

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Parmeliaceae. It is found in South America.

Taxonomy

The lichen was formally described as a new species in 1984 by Belgian lichenologist

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 ...

, from collections made in the

Andean Mountains The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S l ...

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

. The type specimen was collected near

Medellín Medellín ( or ), officially the Municipality of Medellín ( es, Municipio de Medellín), is the second-largest city in Colombia, after Bogotá, and the capital of the department of Antioquia. It is located in the Aburrá Valley, a central re ...

, at an altitude of . 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 ...

''colombiana'' refers to the country where it was first scientifically documented. The species was later recorded in Argentina and Brazil (

Rio Grande do Sul Rio Grande do Sul (, , ; "Great River of the South") is a Federative units of Brazil, state in the South Region, Brazil, southern region of Brazil. It is the Federative_units_of_Brazil#List, fifth-most-populous state and the List of Brazilian st ...

Description

The thallus of ''Punctelia colombiana'' attains a diameter of up to . It is tightly attached to its bark

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

, and has a greenish-gray to ash-grey colour.

Pseudocyphella Pseudocyphellae (singular ''pseudocyphella'') are structures in lichens that appear as tiny pores on the outer surface (the cortex of the lichen. They are caused when there is a break in the cortex of the lichen, and the medullary hyphae extend t ...

e are white, small (measuring 0.1–0.2 mm in diameter) and evenly distributed throughout the thallus surface. Isidia are present over much of the surface. The medulla is white, and it measures 80.0–130.0

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 ...

thick. The thallus undersurface is mostly black with a dark brown zone around the margin. Rhizines are dark brown to black, with a branching pattern ranging from unbranched to irregular; they are abundant and evenly distributed around the margin. The upper cortex is paraplenctenchymatous; this refers to a type of tissue in which the

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

e are oriented in all directions, and is analogous to the

parenchyma Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word π ...

of plants. The upper cortex is covered by a thin epicortex, although it is ruptured on the areas above the pseudocyphellae. The pseudocyphellae are formed from the rupture and disintegration of the upper cortex cells, which exposes the hyphae of the medulla. The size of the pore gradually increases as the cells around the inside perimeter disintegrate and the medullary hyphae grow into the pore area. Air pockets, called aeroplectenchyma, occur under the upper cortex in the region in contact with the algal layer. These pockets are thought to help with the internal diffusion of gases produced during photosynthesis of the algal component of the lichen. The

conidia A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the ...

(asexual spores) are threadlike (filiform), measuring 9–12 by 1

. Ascospores are

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

, 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 or s ...

, and measure 14–16 by 10–13 μm. Major secondary chemicals present in the lichen are atranorin and gyrophoric acid.

Similar species

A 1996 study compared the morphological and chemical differences between ''Punctelia colombiana'' and ''

Punctelia stictica ''Punctelia stictica'' is a species of foliose lichen in the family Parmeliaceae. It is widely distributed lichen, recorded in Africa, Europe, North America, South America, and Greenland. It is typically found saxicolous lichen, growing on rocks. ...

'', concluding that the species are closely related but distinct, and are possibly derived from ''

Punctelia jujensis ''Punctelia jujensis'' is a species of foliose lichen in the family Parmeliaceae. It is found in Argentina and Brazil. Taxonomy The lichen was described as a new species by Argentinian lichenologist Mónica Adler in 1989. The type specimen was ...

''. A lookalike species is '' Punctelia constantimontium'', also found in South America. It is distinguished from ''P. colombiana'' by its hook-like (''unciform'') conidia, and its persistently flat lobulae that never develop into isidia.

References

{{Taxonbar, from=Q10646739

colombiana ''Colombiana'' is a 2011 French English-language action thriller film co-written and produced by Luc Besson and directed by Olivier Megaton. The film stars Zoe Saldaña with supporting roles by Michael Vartan, Cliff Curtis, Lennie James, Callum ...

Lichen species Lichens described in 1984 Lichens of Argentina Lichens of South Brazil Lichens of Colombia Taxa named by Emmanuël Sérusiaux