genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

foliose lichen A foliose lichen is a lichen with flat, leaf-like , which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common growth forms of lichens. It typically has distinct upper and lower surfaces, each o ...

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'' ( 82 ...

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

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 ...

gas exchange Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a b ...

isidia An isidium (plural: isidia) is a tiny, wart- or finger-like outgrowth on the thallus surface of certain lichen species. It is one of two principal types of vegetative reproduction, vegetative reproductive structures in lichens, the other being ...

depsidone Depsidones (+ " depside" + "one") are chemical compounds that are sometimes found as secondary metabolites in lichens. They are esters that are both depsides and cyclic ethers. An example is norstictic acid Norstictic acid is a depsidone produ ...

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

evolutionary history The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as ''Ga'', for '' gigaannum'') and ...

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Melanohalea peruviana'' in the Peruvian

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

and '' M. mexicana'' in Mexico represent the genus's limited

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

distribution. The distribution of these lichens, which are sensitive

indicators Indicator may refer to: Biology * Environmental indicator of environmental health (pressures, conditions and responses) * Ecological indicator of ecosystem health (ecological processes) * Health indicator, which is used to describe the health ...

of climate and pollution effects, is largely determined by current ecological and geographical factors. Certain species show vulnerability to

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

and environmental pollutants. Many species of lichenicolous (lichen-dwelling) fungi are known to

parasitise Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

the lichen. Several ''Melanohalea'' species are listed as

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

or

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

on national red lists across Europe, reflecting their varying levels of threat due to

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

, pollution, and climate change. Only '' M. halei'' has been assessed globally by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

and is listed as being of

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

due to its widespread distribution and stable population.

Taxonomy

''Melanohalea'' was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

in 2004 by the lichenologists Oscar Blanco,

Ana Crespo Ana María Crespo de las Casas (born 30 March 1948, Santa Cruz de Tenerife) is a Spanish lichenologist noted for studying the phytosociology, taxonomy and floristics of Mediterranean lichens. She was awarded the 2012 Acharius Medal from the Int ...

, Pradeep Divakar, Theodore Esslinger, David L. Hawksworth and H. Thorsten Lumbsch. It is a segregate of '' Melanelia'', a genus created in 1978 to contain the brown '' Parmelia'' species. The circumscription of this genus was questioned later, especially after

molecular phylogenetics 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 ...

studies published in 2004 and 2006 demonstrated that it was not

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. Subsequently, two genera, '' Melanelixia'' and ''Melanohalea'', were created. Melanohalea originally comprised 19 species, with '' M. exasperata'' serving as the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

. The species transferred to ''Melanohalea'' were formerly included in

section Section, Sectioning, or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sig ...

''Vainioellae'' of genus ''Melanelia''. This section, in turn, was derived from ''Parmelia''

subgenus In biology, a subgenus ( subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the ge ...

''Euparmelia'' sect. ''Vainioellae'', originally proposed by Vilmos Gyelnik in 1932. Section ''Vainioellae'' included "brown parmelioids" with wide, rounded to elongated lobes that were predominantly flat. The "brown parmelioids" refers to ''Parmelia'' species lacking

atranorin Atranorin is a chemical substance produced by some species of lichen. It is a secondary metabolite belonging to a group of compounds known as depsides. Atranorin has analgesic, anti-inflammatory, antibacterial, antifungal, cytotoxic, antioxidant, ...

or

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 and 1937 by Frank H. Curd and Al ...

in the cortex, with a dark to medium-brown thallus colour. Molecular phylogenetic analysis has shown that genus ''Melanohalea'' is part of the "Melanohalea"

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

, a lineage that includes most of the other "brown parmelioids". Other genera in this clade are '' Emodomelanelia'', '' Melanelixia'', '' Montanelia'', and '' Pleurosticta''. The genus name combines ''Melanelia'' with the name of the lichenologist

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

, who, according to the authors, "provided the foundations for subsequent contributions to our knowledge of this family".

Diversification

Methods used to estimate the

evolutionary divergence Divergent evolution or divergent selection is the accumulation of differences between closely related populations within a species, sometimes leading to speciation. Divergent evolution is typically exhibited when two populations become separate ...

of taxa, including the

multispecies coalescent process Multispecies Coalescent Process is a stochastic process model that describes the genealogical relationships for a sample of DNA sequences taken from several species. It represents the application of coalescent theory to the case of multiple species. ...

, suggest that most of the diversification of ''Melanohalea'' occurred throughout the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

(23.03 million to 5.333 million BP) and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58glacial cycle An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and gr ...

s of the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, it was not accompanied by

speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...

in ''Melanohalea''.

Description

''Melanohalea'' lichens have a

foliose A foliose lichen is a lichen with flat, leaf-like , which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common lichen growth forms, growth forms of lichens. It typically has distinct upper and lo ...

(leafy)

thallus Thallus (: 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. A thallus usually names the entir ...

that is loosely to moderately attached to its . The upper size limit of the thallus is about in diameter. The comprising the thallus are flat to concave with rounded tips, lack , and measure 0.5–7 mm wide. The upper surface of the thallus is olive-green to dark brown, ranging in texture from smooth to wrinkled, and lacks spots or stains. It usually features

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 ...

e on warts or on the tips of

isidia An isidium (plural: isidia) is a tiny, wart- or finger-like outgrowth on the thallus surface of certain lichen species. It is one of two principal types of vegetative reproduction, vegetative reproductive structures in lichens, the other being ...

; the presence of

soredia Soredia are common reproduction, reproductive structures of lichens. Lichens asexual reproduction, reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungus, fung ...

and isidia is variable. The upper

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

is (a cell arrangement where 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 o ...

e are oriented in all directions), and measures 10–16 mm thick. The does not have pores, unlike in the related genus ''Melanelixia''. The medulla is white, and the lower thallus surface is smooth and flat and coloured pale brown to black.

Rhizine In lichens, rhizines are multicellular root-like structures arising mainly from the lower surface. A lichen with rhizines is termed rhizinate, while a lichen lacking rhizines is termed erhizinate. Rhizines serve only to anchor the lichen to their s ...

s are (i.e., unbranched), and the same colour as the lower surface. The

ascomata An ascocarp, or ascoma (: ascomata), is the fruiting body (sporocarp (fungi), sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded ascus, asci, each of which typically contains four to ...

(fruiting bodies) are

apothecia An ascocarp, or ascoma (: ascomata), 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. As ...

l, , and

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

to more or less

pedicellate In botany, a pedicel is a stem that attaches a single flower to the inflorescence. Such inflorescences are described as ''pedicellate''. The stalk at the base of a leaf is called a petiole. Description Pedicel refers to a structure connecti ...

. The apothecial is brown, and is not perforated. It is initially concave but becomes convex with age. The (a layer of cells that surrounds the apothecium) has pseudocyphellate , without spots or stains. Asci are elongated, club-shaped (), ''

Lecanora ''Lecanora'' is a genus of lichen commonly called rim lichens.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, Lichens in the genus '' Squamarina'' are also called rim lichens. Members of the genus have roughly c ...

''-type, and thickened at the tip. They lack an internal apical beak, and have between 8 and 32 spores.

Ascospore In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...

s of ''Melanohalea'' are spherical to ovoid or

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

in shape, thin-walled, colourless, and measure 5.5–20 by 4–12.5

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

. The

conidiomata Conidiomata (singular: Conidioma) are blister-like fruiting structures produced by a specific type of fungus called a coelomycete. They are formed as a means of dispersing asexual spores call conidia, which they accomplish by creating the blister- ...

are

pycnidia A pycnidium (plural pycnidia) is an asexual fruiting body produced by mitosporic fungi, for instance in the order Sphaeropsidales ( Deuteromycota, Coelomycetes) or order Pleosporales (Ascomycota, Dothideomycetes). It is often spherical or inve ...

l, immersed, and laminal. The shape of the

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

ranges from cylindrical to (spindle-shaped); they are simple (i.e., lacking partitions called

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

), colourless, and measure 5–8.5 μm long by 1 μm wide. The of the lichen is , i.e., resembling or belonging to the

green alga The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ( ...

l genus ''

Trebouxia ''Trebouxia'' is a unicellular green alga. It is a photosynthetic organism that can exist in almost all habitats found in polar, tropical, and temperate regions.Erokhina, L. G., Shatilovich, A. V., Kaminskaya, O. P., & Gilichinskii, D. A. (2004 ...

''.

Chemistry

The cortex of ''Melanohalea'' lichens has a brown

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

, but lacks other compounds. All chemical spot tests are negative on the cortex. The medulla either contains

depsidone Depsidones (+ " depside" + "one") are chemical compounds that are sometimes found as secondary metabolites in lichens. They are esters that are both depsides and cyclic ethers. An example is norstictic acid Norstictic acid is a depsidone produ ...

s (including fumarprotocetraric, protocetraric, and

norstictic acid Norstictic acid is a depsidone produced as a secondary metabolites in lichens. The compound contains both an aldehyde carbonyl group and an adjacent hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical fo ...

) or lacks

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

s. Depending on the species, the spot test results on the medulla are K− or K+ (yellow to red), KC− or KC+ (pink), and P− or P+ (red, red-orange, or yellow to orange). ''M. nilgirica'' contains the

aliphatic compound In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated (in which all ...

caperatic acid, which is rare in the brown parmelioid lichens, known only to exist in '' Melanelia stygia'', the type species of ''Melanelia''. For this reason its placement in ''Melanohalea'' has been questioned.

Cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...

s of ''Melanohalea'' lichens contain the

α-glucan α-Glucans (alpha-glucans) are polysaccharides of D-glucose monomers linked with glycosidic bonds of the alpha form. α-Glucans use cofactors in a Cofactor (biochemistry), cofactor site in order to activate a glucan phosphorylase enzyme. This enzy ...

compound isolichenan.

Similar genera

''Melanohalea'' can be mistaken for certain brown species of ''

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

'', which were previously categorised as ''Neofuscelia''. They can be differentiated by their distinct reactions to

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

; brown ''Xanthoparmelia'' species typically have a blue-green reaction, whereas ''Melanohalea'' shows no reaction. Moreover, the cell wall composition of ''Melanohalea'' differs, consisting of isolichenan instead of the ''Xanthoparmelia''-type polysaccharide ( lichenan). ''Pleurosticta'', although similar to ''Melanohalea'', is characterised by wider lobes, a network of epicortical pores, and a pigment that turns violet upon reacting with both

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

(K) and

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

(N). ''Melanelixia'' is identified by its pored epicortex and absence of pseudocyphellae, while ''Melanelia'' is distinguished by its flat and spread-out pseudocyphellae, as opposed to the raised pseudocyphellae found in ''Melanohalea''.

Habitat and distribution

Most ''Melanohalea'' occur primarily on bark and on wood throughout the

Holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

; only four species occur in the Southern Hemisphere. Occasionally, they are found growing on rock. '' Melanohalea peruviana'' is the only species in the genus that has been reported from

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

South America, although it is poorly known – a single collection from an altitude of in the Peruvian

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. The only other ''Melanohalea'' species found in a tropical habitat is '' M. mexicana'', a

highland Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills. Generally, ''upland'' refers to a range of hills, typically from up to , while ''highland'' is usually reserved for range ...

species from south central Mexico, and one of three ''Melanohalea'' species known to occur in that country. Eight members of the genus are found in China; five in Great Britain and Ireland, and seven occur in the

Nordic Nordic most commonly refers to: * Nordic countries, the northern European countries of Denmark, Finland, Iceland, Norway and Sweden, and their North Atlantic territories * Scandinavia, a cultural, historical and ethno-linguistic region in northern ...

lichen flora. The five ''Melanohalea'' species found in

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

may play a role in monitoring the impact of climate change, as arctic-alpine lichens are sensitive to fluctuations in the temperature of winter climates, and winter icing events affect lichen-dominated ecosystems. Similarly, a study of the effect of

air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

surrounding the Mongolian capital

Ulan Bator Ulaanbaatar is the capital and most populous city of Mongolia. It has a population of 1.6 million, and it is the coldest capital city in the world by average yearly temperature. The municipality is located in north central Mongolia at an ...

showed widespread damage to a variety of lichens (where the thallus was bleached, deformed, or reduced in size), including '' Melanohalea septentrionalis''. Most ''Melanohalea'' species have a broad geographic distribution, although there are a few that have more restricted ranges. Otte and colleagues suggested in a 2005 study that distribution patterns in ''Melanohalea'' are largely determined by contemporary ecogeographical factors, and most species have reached their biogeographical limits in the Northern Hemisphere. The distributions of ''M. elegantula'' and ''M. exasperatula'' seem to be affected by

anthropogenic Anthropogenic ("human" + "generating") is an adjective that may refer to: * Anthropogeny, the study of the origins of humanity Anthropogenic may also refer to things that have been generated by humans, as follows: * Human impact on the enviro ...

factors, including

eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

and

air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

. ''Melanohalea olivacea'' and ''M. septentrionalis'', both cold-tolerant circumpolar species, have the south-west limit of their distribution range in Switzerland. They are considered

relicts A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

of the last ice age and are vulnerable to global

climate warming Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes ...

in that country.

Species interactions

Several species of

lichenicolous fungi A lichenicolous fungus is a member of a specialised group of fungi that live exclusively on lichens as their host (biology), host organisms. These fungi, comprising over 2,000 known species across 280 genera, exhibit a wide range of ecological st ...

have been recorded growing on ''Melanohalea'' species. These include '' Epithamnolia xanthoriae'', '' Xenonectriella septemseptata'', '' Plectocarpon melanohaleae'' (on ''M. ushuaiensis''), '' Abrothallus bertianus'', '' Zwackhiomyces melanohaleae'' (on ''M. exasperata''), '' Phoma melanohaleicola'' (on ''M. exasperata''), '' Didymocyrtis consimilis'', '' Stigmidium exasperatum'' (on ''M. exasperata''), '' Sphaeropezia melaneliae'' (on ''M. olivacea''), '' Arthrorhaphis olivaceae'' (on ''M. olivacea''), '' Epithamnolia xanthoriae'', '' Xenonectriella septemseptata'', '' Plectocarpon melanohaleae'' (on ''M. ushuaiensis''), and '' Stagonospora exasperatulae'' (on ''M. exasperatula''). '' Crittendenia coppinsii'' (on ''M. exasperatula''), Recent revisions of the poorly known genus lichenicolous '' Crittendenia'' (

Pucciniomycotina Pucciniomycotina is a subdivision of fungus within the division Basidiomycota. The subdivision contains 10 classes, 21 orders, and 38 families. Over 8400 species of Pucciniomycotina have been described - more than 8% of all described fungi. T ...

) revealed '' Crittendenia coppinsii'' (on ''M. exasperatula'') and '' C. crassitunicata'' (on ''M. ushuaiensis'') as parasites of the genus.

Conservation

''Melanohalea septentrionalis'' is listed as

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

on the

Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological sp ...

of Switzerland. ''Melanohalea exasperata'' is on the German national Red List, and is in the

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

category in Poland's Red list of extinct and vulnerable lichens of Poland. Although ''M. olivacea'' was left off this list over uncertainties about its taxonomic status, it has been preliminarily assessed as critically endangered in Switzerland using the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

criteria. It has received the same assessment in the neighbouring countries Germany and France. ''M. elegantula'' is red-listed in Sweden. ''Melanohalea halei'' is the only species in this genus that has been assessed for the global

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

. Because of its broad geographic distribution, breadth of ecological niches, and large, stable population size, it has been assessed as a

least-concern species A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

.

Species

''Melanohalea'' originally included 19 species transferred from ''Melanelia''. In the following years, new species in the genus were described from India, Tibet, Mexico, and Peru. In 2016, Leavitt and colleagues used genetic analyses to help identify six previously undescribed morphologically

cryptic species In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

in ''Melanohalea''. ,

Species Fungorum ''Index Fungorum'' is an international project to index all formal names (Binomial nomenclature, scientific names) in the fungus Kingdom (biology), kingdom. As of 2015, the project is based at the Royal Botanic Gardens, Kew, one of three partn ...

accepts 30 species of ''Melanohalea''. *'' Melanohalea austroamericana'' *'' Melanohalea beringiana'' *'' Melanohalea clairi'' *'' Melanohalea columbiana'' *'' Melanohalea davidii'' *'' Melanohalea elegantula'' *'' Melanohalea exasperata'' *'' Melanohalea exasperatula'' *'' Melanohalea gomukhensis'' *'' Melanohalea halei'' *'' Melanohalea inactiva'' *'' Melanohalea infumata'' *'' Melanohalea laciniatula'' *'' Melanohalea lobulata'' – Tibet *'' Melanohalea mexicana'' – Mexico *'' Melanohalea multispora'' *'' Melanohalea nilgirica'' – India *'' Melanohalea olivacea'' *'' Melanohalea olivaceoides'' *'' Melanohalea peruviana'' – Peru *'' Melanohalea poeltii'' – Nepal; India *'' Melanohalea septentrionalis'' – North America; Europe; Asia *'' Melanohalea subelegantula'' – western North America; Tibet *'' Melanohalea subexasperata'' – Tibet *'' Melanohalea subolivacea'' *'' Melanohalea subverruculifera'' *'' Melanohalea tahltan'' *'' Melanohalea trabeculata'' *'' Melanohalea ushuaiensis'' *'' Melanohalea zopheroa''

References

{{Taxonbar, from=Q10580432 * Lecanorales genera Lichen genera Taxa described in 2004 Taxa named by Ana Crespo Taxa named by Pradeep Kumar Divakar Taxa named by Theodore Lee Esslinger Taxa named by David Leslie Hawksworth Taxa named by Helge Thorsten Lumbsch