Collemopsidium | |
---|---|
![]() | |
Collemopsidium foveolatum on barnacles in Lourinhã, Portugal. The fungus is visible as black dots on the shell. | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Dothideomycetes |
Order: | Collemopsidiales |
Family: | Xanthopyreniaceae |
Genus: | Collemopsidium Nyl. (1881) |
Type species | |
Collemopsidium iocarpum (Nyl.) Nyl. (1881) | |
Species | |
18 species; see text | |
Synonyms [1] | |
Collemopsidium is a genus of fungi in the family Xanthopyreniaceae. [3] Some members of this genus are marine species, and described as "borderline lichens" or "algicolous" fungi. [4]
The genus was circumscribed by the Finnish lichenologist William Nylander in 1881, with Collemopsidium iocarpum assigned as the type species. [5]
Species of Collemopsidium form what are known as "borderline lichens" – relatively loose symbiotic associations between fungi and photosynthetic partners. The fungal portion develops an extremely thin thallus (body) that can either grow on the surface of the substrate or be completely embedded within it. When growing on the surface, the thallus appears orange-brown, smooth, and shiny. Some species may develop black carbonaceous (blackened) ridges. [6]
The photosynthetic partner is typically Hyella caespitosa , a type of cyanobacterium that contains an orange pigment. While this cyanobacterium normally grows as filaments when living freely on mollusk shells, within the lichen partnership it usually exists as single cells measuring 3–10 micrometres in diameter. These cells may be evenly scattered throughout the thallus or concentrated in clumps, giving the lichen a blotchy appearance. In some specimens growing on shells or limestone, the photosynthetic partner may be absent. [6]
The fungal reproductive structures (ascomata) can occur either singly or in groups and feature a black carbonaceous protective covering ( involucrellum ). Each reproductive structure contains spore-producing sacs (asci) with eight spores that are divided into two cells (one-septate). The internal structure includes intricately branched and persistent thread-like filaments ( pseudoparaphyses ). The species also commonly produce smaller spore-containing structures called pycnidia, which externally resemble miniature versions of the main reproductive structures. No secondary metabolite have been detected in these lichens. [6]
Collemopsidium species are nearly cosmopolitan in distribution, occurring along tropical, subtropical, temperate, and arctic coastlines in both hemispheres. They display considerable tolerance to variations in temperature and salinity. These lichens can be found in the eulittoral (intertidal) and littoral fringe zones, growing on both siliceous and calcareous rock as well as on the shells of various marine organisms. [7] Records show they colonise at least 61 different species of molluscs and barnacles, mostly in the intertidal zone, though some host species like periwinkles ( Littorina ) can live quite high in the littoral fringe. [7]
The substrate significantly influences their growth patterns. On siliceous rock, the thallus always grows on the surface, and the reproductive structures remain above the substrate. On calcareous rock and shells, the thallus may grow either on the surface or become embedded within the substrate, with reproductive structures that can be either surface-level or immersed. Different forms are commonly found growing side by side on the same substrate. [7] While the lichens do not appear to harm their living substrates, they can alter the nature of shell matrices, sometimes affecting shell appearance to such an extent that it causes taxonomic confusion in limpet species. [7]
Limestone shores typically show less distinct zonation of lichens in the eulittoral and littoral fringe zones compared to siliceous shores, and display lower species diversity. However, Collemopsidium species often achieve higher coverage on limestone shores due to their ability to grow within the substrate, allowing them to persist despite erosion. [6]
As of January 2025 [update] , Species Fungorum (in the Catalogue of Life) accept 18 species. of Collemopsidium: [8]
Byssoloma is a genus of leaf-dwelling lichens in the family Pilocarpaceae.
Micarea is a genus of lichen-forming fungi in the family Pilocarpaceae. The widely distributed genus contains 142 species and new species are described actively. Species in the genus are crustose lichens and their photobiont is a single-celled green alga.
Arthothelium is a genus of lichen-forming fungi in the family Arthoniaceae.
Mazosia is a genus of lichen-forming fungi in the family Roccellaceae.
Anisomeridium is a genus of lichens in the family Monoblastiaceae. The type species was originally named Arthopyrenia xylogena by Swiss botanist Johannes Müller Argoviensis in 1883; in 1928, Maurice Choisy defined the genus Anisomeridium, designating A. xylogena the type species.
Agonimia is a genus of lichen-forming fungi in the family Verrucariaceae.
Tylophoron is a genus of lichen-forming fungi in the family Arthoniaceae. It comprises seven species of crustose lichens, most of which occur in tropical regions.
Zwackhiomyces is a genus of lichenicolous (lichen-dwelling) fungi in the family Xanthopyreniaceae.
Porpidia is a genus of crustose lichens in the family Lecideaceae. Porpidia species primarily inhabit siliceous rocks, pebbles, and stonework, with rare occurrences on bark, wood, and compacted soil. The thallus, or body of the lichen, varies in appearance from thick and crusty to barely visible. It may form a continuous layer or develop cracks resulting in a segmented, areolate structure. The colour of the thallus ranges from grey and white to orange.
Synarthonia is a genus of lichen-forming fungi in the order Arthoniales. The genus has not been placed into a family.
Megalaria is a genus of lichen-forming fungi in the family Ramalinaceae. It contains 44 species of crustose lichens, the majority of which grow on bark.
Hydropunctaria is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. The genus includes both aquatic and amphibious species, with members that colonise either marine or freshwater habitats. The type species, Hydropunctaria maura, was formerly classified in the large genus Verrucaria. It is a widely distributed species common to littoral zones. Including the type species, five Hydropunctaria lichens are considered marine species: H. adriatica, H. amphibia, H. aractina, H. orae, and H. oceanica.
Schizotrema is a genus of lichen-forming fungi in the family Graphidaceae. The genus was circumscribed in 2009 by Armin Mangold and H. Thorsten Lumbsch.
Swinscowia is a genus of lichen-forming fungi in the family Strigulaceae. It has 34 species. Swinscowia was proposed in 2020 by lichenologists Shu-Hua Jiang, Robert Lücking, and Emmanuël Sérusiaux to contain non-foliicolous species that were isolated from bark and rocks. Swinscowia jamesii, a species that was originally described in genus Geisleria, and later transferred to Strigula, is the type species of the genus. The genus name honours British lichenologist Dougal Swinscow, who originally described the type species in 1967.
Leptogidium is a genus of lichen-forming fungi in the family Pannariaceae. It has six species.
Celothelium is a genus of lichen-forming fungi in the family Celotheliaceae. These lichens typically have a thin, crust-like thallus that often grows beneath the surface of tree bark or rocks in tropical rainforests and coastal areas. Celothelium species are characterised by small, black, shiny reproductive structures (perithecia), and thread-like spores. The genus has had an uncertain taxonomic history since its original description in 1860, but recent genetic studies have placed it in its own distinct group within the fungal class Eurotiomycetes. Celothelium species have been found in various parts of the world, including Asia, Europe, and the Americas.
Collemopsidium sublitorale is a species of lichen in the family Xanthopyreniaceae. First described in 1871, it forms a "borderline" symbiotic relationship with cyanobacteria that is less structured than typical lichen partnerships. The species is characterised by an immersed thallus and black, roughly spherical fruiting bodies measuring 0.15–0.55 mm in diameter. It grows in the intertidal and littoral fringe zones of marine environments, exclusively on calcareous substrates such as limestone and marine shells. Studies have documented its presence along both exposed and sheltered coastlines in northwest Europe, where it typically occurs in shaded positions lower in the tidal zone.
Collemopsidium foveolatum is a species of lichen in the family Xanthopyreniaceae. It is a marine lichen that grows entirely embedded within calcareous substrates in the intertidal zone, particularly on limestone rocks and marine shells. The species is characterised by its minute, black, sunken reproductive structures that measure 0.10–0.24 mm in diameter and create small pits in the substrate. First described in 1911 from specimens collected in England, it has since been documented along coastlines in western Europe, North America and North Africa. The species can be distinguished from similar marine lichens by its consistently small, deeply embedded perithecia and its ability to maintain stable growth by keeping pace with natural substrate erosion.