Namibialina

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Namibialina
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Family: Ramalinaceae
Genus: Namibialina
Spjut & Sérus. (2020)
Species:
N. melanothrix
Binomial name
Namibialina melanothrix
(Laurer) Spjut & Sérus. (2020)
Synonyms [1]
  • Ramalina melanothrixLaurer (1860)
  • Ramalina capensis var. melanothrix(Laurer) Th.Fr. (1861)
  • Desmazieria melanothrix(Laurer) C.W.Dodge (1971)
  • Trichoramalina melanothrix(Laurer) Rundel & Bowler (1974)
  • Niebla melanothrix(Laurer) Kistenich, Timdal, Bendiksby & S.Ekman (2018)

Namibialina is a fungal genus in the family Ramalinaceae. [2] [3] It comprises the single species Namibialina melanothrix, a fruticose lichen. The genus is endemic to the coastal deserts of southwestern Africa, from southern Angola to South Africa's Cape of Good Hope, where it grows on rocks, soil, or as an epiphyte on tree bark. It is characterized by its shrubby thallus with branching patterns that often end in blackish or hair-like projections, and by distinctive longitudinal grooves formed by cartilage-like tissue. The genus was circumscribed in 2020 based on molecular phylogenetic evidence showing it diverged from its sister genus Ramalina about 48 million years ago during the early Eocene.

Contents

Taxonomy

The genus Namibialina was circumscribed in 2020 by the lichenologists Richard Sjput and Emmanuël Sérusiaux to accommodate species previously classified in other genera of the Ramalinaceae. Phylogenetic analysis revealed that these species formed a distinct lineage that diverged from its sister genus Ramalina approximately 48 million years ago during the early Eocene. [4] [5]

The type species, Namibialina melanothrix, has undergone several taxonomic transfers since its original description as Ramalina melanothrix by Johann Friedrich Laurer in 1860. [6] It was later moved to Trichoramalina by Philip Rundel and Peter Bowler in 1974, [7] and subsequently transferred to Niebla by Sonja Kistenich and colleagues in 2018. [8] Although the genus lacks clear-cut morphological, anatomical, or chemical autapomorphies, its significant evolutionary divergence from Ramalina supported its recognition as a separate genus. [4]

Molecular phylogenetic studies have shown that specimens previously identified as "Ramalina angulosa" represent a paraphyletic assemblage of at least three distinct species, with N. melanothrix nested among them. The full diversity of the genus is likely undersampled, as available DNA sequences are primarily from specimens collected along just 120 kilometers of Namibian coastline. [4]

The genus name combines Namibia, referencing its geographic distribution in the coastal deserts of southwestern Africa, with the suffix -lina, which is commonly used in lichen taxonomy and appears in the related genus name Ramalina. The species delimitation within Namibialina remains partially unresolved. While N. melanothrix is clearly defined, the taxonomy of the "angulosa" complex requires further study, with preliminary evidence suggesting the existence of multiple undescribed species throughout its range from southern Angola to South Africa's Cape of Good Hope. [4]

Description

The genus Namibialina consists of shrubby (fruticose) lichens that typically emerge from a single, anchoring holdfast. Their thalli (lichen bodies) can vary in size, reaching several centimeters tall on tree bark (epiphytic) or rock (saxicolous) surfaces, and sometimes forming compact, cushion-like clusters on soil. When growing in cushions, these can be up to about 10–15 cm (4–6 in) in diameter and 2–6 cm (0.8–2.4 in) high. The thallus is usually pale green or has a yellowish-green hue, giving the lichen a distinctive, subdued colouration. [4]

The branches of Namibialina generally divide in a branching pattern that may be regular or irregular, with some splitting in a "Y"-shaped ( dichotomous ) manner. Many branch tips end in slender, hair-like projections or are capped with blackish hairs. The main branches tend to be round or slightly flattened, with noticeable grooves or channels along their length. These grooves arise from thick strands of cartilage-like tissue that provide structural integrity. Smaller lateral branches and spines may be present, but this genus does not produce specialized reproductive structures called isidia or powdery reproductive areas known as soralia. [4]

Internally, the medulla—a central layer of the thallus—has a delicate, cobweb-like ( arachnoid ) structure. The cortex , or outer protective layer, has two layers but may show some variation in structure. Namibialina lichens sometimes produce apothecia (fruiting bodies), which are saucer-shaped and located at the branch tips or edges; these structures are oriented perpendicular to the branch. The spores produced in the apothecia are small, ellipsoid in shape, and have a single septum (internal partition). [4]

The genus produces usnic acid, a secondary metabolite commonly found in lichen that lends a yellowish tint to the cortex and provides some protection against sunlight. [4]

Habitat and distribution

Namibialina species are restricted to coastal desert areas of southwestern Africa, where they can grow as epiphytes or on rocks, although they also form terricolous shrubby cushions. Current collections are known from approximately 120 km of coastline north of Swakopmund, Namibia, though the genus is suspected to be more widely distributed along the coastal deserts from southern Angola to the Cape of Good Hope. [4]

Related Research Articles

<span class="mw-page-title-main">Ramalinaceae</span>

The Ramalinaceae are a family of lichen-forming fungi in the order Lecanorales. First proposed by Carl Adolph Agardh in 1821, the family now comprises 63 genera and about 750 species. Ramalinaceae lichens exhibit diverse growth forms, including crustose, fruticose, squamulose, leprose, and byssoid thalli, and form symbiotic relationships primarily with green algae of the genus Trebouxia. The family is characterised by pale-coloured thalli, apothecia that are typically pale but may darken with age, and ascospores that vary in shape and septation.

<i>Ramalina</i> Genus of lichen-forming fungi

Ramalina is a genus of greenish fruticose lichens that grow in the form of flattened, strap-like branches. Members of the genus are commonly called strap lichens or cartilage lichens. Apothecia are lecanorine.

Vermilacinia, a genus of lichenized fungi in the family Ramalinaceae, is a yellow-green fruticose type of lichen with about 30 species that grow on rocks, trees, and soil within the fog zone along the Pacific Coast of North America and South America. The genus name refers to the thallus being divided into narrow worm-like (vermis) branches (lacinia);the latter part of the name (lacinia) generally applied in descriptions and taxonomic keys such as exemplified in a key to Sonoran Desert species of Ramalina.

<i>Niebla</i> (lichen) Genus of lichen

Niebla, also known as the sea-fog lichens, is a genus of yellow-green fruticose lichens that grow on rocks, trees, and shrubs within the fog zone of coastal North America, or more narrowly defined to occur on rocks and soil along the Pacific Coast from Mendocino County in California south to Baja California Sur.

<i>Niebla homalea</i> Species of lichen

Niebla homalea is a species of fruticose lichen that grows on rocks in foggy areas along the Pacific Coast of North America, from Mendocino County, California south to Bahía de San Quintín on the main peninsula of Baja California, with an isolated occurrence further south on vertical rock faces above Punta Camachos, and other occurrences in the Channel Islands and on Guadalupe Island. The epithet homalea, given by Acharius, suggests it was in regard to the branches appearing flattened.

Vermilacinia cedrosensis is a species of pale fruticose lichen that is endemic to Baja California, Mexico.

Vermilacinia ceruchoides is a fruticose lichen found on rock faces of cliffs or boulders, sometimes growing among mosses, usually near the ocean, ranging in distribution from Marin County, California to San Vicente on the northern peninsula of Baja California, and in the Channel Islands.

Vermilacinia laevigata is a fruticose lichen that occurs in the fog zone along the Pacific Coast of the California Floristic Province from Marin County, California to 15 miles south of Misión San Vicente Ferrer in Baja California.

Vermilacinia polymorpha is a fruticose lichen infrequently found on Santa Catalina Island in the Channel Islands of California and along the mainland coast in Ventura and Orange counties. It has also been indicated to occur south into northwestern Baja California without reference to specimens to support its range extension, and shown to occur on the Vizcaíno Peninsula in central Baja California on a distribution map in a lichen flora, without reference to specimen data; however, specimen data from other sources indicate it does occur as far south as Punta Santa Rosalillita on the main peninsula of Baja California, and also reported from Guadalupe Island.

Vermilacinia robusta is an olive-green fruticose lichen that occurs on rocks near ocean mist along the foggy Pacific Coast of southern California to northern Baja California and offshore islands. The epithet, robusta, was probably adopted in recognizing a more robust form of V. comboides, originally described as a variety of Ramalina combeoides by Reginald Heber Howe, Jr. in 1913.

Vermilacinia cephalota is a fruticose lichen usually found on trees, shrubs and wooden fences in the fog regions along the Pacific Coast of North America from southeastern Alaska to the Vizcaíno Peninsula of Baja California.

Vermilacinia flaccescens is a fruticose lichen that grows on cacti and shrubs in the fog regions along the Pacific Coast of South America, Peru, Chile and in the Juan Fernandez Islands The epithet is in reference to the flaccid thallus but some specimens have been interpreted to have rigid branches.

Vermilacinia tigrina is a fruticose lichen that grows on branches of shrubs and on earth among cactus and shrubs in the fog regions along the Pacific Coast of North America and South America; in North America found in the Channel Islands and near San Diego, California, and in central and southern Baja California; and in South America from Peru to Chile. The epithet is in reference to the irregular black spots or bands on the thallus branches.

Vermilacinia zebrina is a fruticose lichen that grows on bark of trees and shrubs, occasionally on rocks, in the fog regions along the Pacific Coast of North America, from Puget Sound in northern Washington to near El Rosario in Baja California. The epithet, zebrina, is in reference to the black transverse bands on the thallus branches; however, the species is interpreted to include thalli without black bands.

Niebla isidiosa is a fruticose lichen known only from Guadalupe Island. The epithet, isidiosa is in reference to isidia (isidium) on the thallus.

Niebla pulchribarbara is a rare fruticose lichen that occurs on sandy beaches or gravelly soil along the Pacific Coast, at San Antonio del Mar and at Bahía de San Quintín, Baja California. The species epithet, pulchribarbara, is in reference to the strikingly beautiful lichen mat formed by the thallus.

Niebla testudinaria is a fruticose lichen that grows on rocks along the foggy Pacific Coast of North America, from Marin County, California to just south of Tijuana in Baja California, in the Channel Islands in California, and Isla San Martín and Guadalupe Island in Baja California The epithet, testudinaria given by William Nylander in 1870, is probably in reference to the dilated branch with a reticulated surface, similar to a tortoise shell.

<span class="mw-page-title-main">Malmideaceae</span> Family of fungi

Malmideaceae is a family of crustose and corticolous lichens in the order Lecanorales. It contains eight genera and about 70 species.

<i>Ramalina peruviana</i> Species of lichen

Ramalina peruviana is a species of fruticose lichen in the family Ramalinaceae with a pantropical distribution. The lichen was first formally described by Erik Acharius in 1810, who wrote of its flat, compressed, branching thallus with narrow, undulating branches. It typically occurs on the bark of trees (corticolous) although occasionally it grows on rocks (saxicolous). Ramalina peruviana is widely distributed, found in subtropical and warm temperate regions across several continents. It has been recorded in diverse locations such as Pacific Islands, the southern United States, East Africa, Asia, Australasia, and South America. Its presence has been documented in specific habitats like mangroves in Australia and on certain tree species in Taiwan and China, where it thrives at higher elevations.

<i>Ramalina europaea</i> Species of lichen

Ramalina europaea is a species of fruticose lichen in the family Ramalinaceae. This species is widely distributed across Europe and is distinguished by its small, punctiform (point-like) soralia that often develop terminally on spine-like branchlets.

References

  1. "GSD Species Synonymy. Current Name: Namibialina melanothrix (Laurer) Spjut & Sérus., in Spjut, Simon, Guissard, Magain & Sérusiaux, MycoKeys 74: 109 (2020)". Species Fungorum . Retrieved 10 November 2024.
  2. "Namibialina". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved 10 November 2024.
  3. Wijayawardene, N.N.; Hyde, K.D.; Dai, D.Q.; Sánchez-García, M.; Goto, B.T.; Saxena, R.K.; et al. (2022). "Outline of Fungi and fungus-like taxa – 2021". Mycosphere. 13 (1): 53–453 [152]. doi:10.5943/mycosphere/13/1/2. hdl: 1854/LU-8754813 .
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  6. Nylander, W. (1860). Synopsis Methodica Lichenum Omnium hucusque Cognitorum, Praemissa Introductione Lingua Gallica[Methodical synopsis of all lichens known so far, with an introduction presented in the French language] (in Latin). Vol. 1. p. 290.
  7. Rundel, Philip W.; Bowler, Peter A. (1974). "The lichen genus Trichoramalina". The Bryologist. 77 (2): 188–194. doi:10.2307/3241555. JSTOR   3241555.
  8. Kistenich, Sonja; Timdal, Einar; Bendiksby, Mika; Ekman, Stefan (2018). "Molecular systematics and character evolution in the lichen family Ramalinaceae (Ascomycota: Lecanorales)". Taxon. 67 (5): 871–904. doi:10.12705/675.1. hdl: 10852/67955 .