| Biatoropsis | |
|---|---|
 | |
| Biatoropsis usnearum | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Tremellomycetes |
| Order: | Tremellales |
| Genus: | Biatoropsis Räsänen (1934) |
| Type species | |
| Biatoropsis usnearum Räsänen (1934) | |
Biatoropsis is a genus of lichenicolous (lichen-dwelling) fungi of uncertain familial placement in the order Tremellales. [1] It comprises 11 species that parasitise various species in the fruticose lichen genera Usnea and Protousnea .
The genus was circumscribed in 1935 by the Finnish lichenologist Veli Räsänen, who assigned Biatoropsis usnearum as the type species. [2] The genus remained monospecific for several decades, until research, starting in the 1990s, [3] showed that B. usnearum represented a species complex. Since then another ten species have been added to the genus. [4] [5]
Biatoropsis is a genus of fungi that parasitises lichens (making it lichenicolous). The fungus produces reproductive structures called basidiomata that vary in both shape and colour, with a waxy-gelatinous texture similar to jelly. [5]
At a microscopic level, the internal tissue (context) consists of thread-like cells called hyphae that lack specialised connecting structures known as clamps. The fungus penetrates its host using specialised feeding structures called haustoria, which have a distinctive twisted or convoluted form characteristic of the Tremellales order of fungi. The reproductive surface (hymenium) contains numerous immature spore-producing cells called probasidia. These initially develop in a club-shaped form and may or may not have a clamp at their base. Unlike some related fungi, Biatoropsis lacks specialised sterile cells called hyphidia and cystidia in its hymenium. [5]
When fully mature, the spore-producing cells (basidia) are club-shaped to almost cylindrical and divided by cross-walls (septa). These cells develop extensions called epibasidia that are roughly cylindrical in shape. The spores (basidiospores) they produce are nearly spherical to elliptical in shape and have a distinctive side projection called an apiculus. When these spores germinate, they do so by producing a tube-like growth. [5]
The fungus can also reproduce asexually in several ways. It commonly produces chains of spores called catenulate conidia. In one rare observation, crescent-shaped (lunate) conidia were documented. In one species of Biatoropsis, the basidia themselves can function as cells that produce asexual spores – these spores are colourless and lack internal divisions. [5]
All species in the genus parasitise speciess of the fruticose lichen genera Usnea and Protousnea , causing galls in infected species. [5]
As of December 2024 [update] , Species Fungorum (in the Catalogue of Life) accepts 11 species of Biatoropsis: [6]
The Tremellales are an order of fungi in the class Tremellomycetes. The order contains both teleomorphic and anamorphic species, most of the latter being yeasts. All teleomorphic species in the Tremellales are parasites of other fungi, though the yeast states are widespread and not restricted to hosts. Basidiocarps, when produced, are gelatinous.
The Sphaerophoraceae are a family of lichen-forming fungi in the order Lecanorales. Species of this family have a widespread distribution, especially in southern temperate regions, with particular diversity in cool temperate rainforests and highly oceanic areas of both hemispheres.
Verrucariales is an order of ascomycetous fungi within the subclass Chaetothyriomycetidae of the class Eurotiomycetes. Although most of the Verrucariales are lichenised, the family Sarcopyreniaceae consists of 11 species of lichenicolous (lichen-dwelling) fungi.
Tremella is a genus of fungi in the family Tremellaceae. All Tremella species are parasites of other fungi and most produce anamorphic yeast states. Basidiocarps, when produced, are gelatinous and are colloquially classed among the "jelly fungi". Over 100 species of Tremella are currently recognized worldwide. One species, Tremella fuciformis, is commercially cultivated for food.
Buellia is a genus of mostly lichen-forming fungi in the family Caliciaceae. The fungi are usually part of a crustose lichen. In this case, the lichen species is given the same name as the fungus. But members may also grow as parasites on lichens (lichenicolous). The algae in the lichen is always a member of the genus Trebouxia.
Roccella is a genus of 23 species of lichens in the family Roccellaceae. The genus was circumscribed by Swiss botanist Augustin Pyramus de Candolle in 1805, with Roccella fuciformis as the type species.
Placomaronea is a genus of lichenized fungi in the family Candelariaceae. It has 6 species. The genus was circumscribed by Finnish lichenologist Veli Räsänen in 1944, with Placomaronea candelarioides assigned as the type species. The genus was revised by Martin Westberg and colleagues in 2009, who accepted six species in the genus.
Phacopsis is a genus of lichenicolous (lichen-dwelling) fungi. They are parasites of members of the large lichen family Parmeliaceae, of which they are also a member. Originally proposed by Edmond Tulasne in 1852 to contain 3 species, Phacopsis now contains 10 species, although historically, 33 taxa have been described in the genus. Many of the species are poorly known, some of them having been documented only from the type specimen.
A lichenicolous fungus is a member of a specialised group of fungi that live exclusively on lichens as their host organisms. These fungi, comprising over 2,000 known species across 280 genera, exhibit a wide range of ecological strategies, including parasitism, commensalism, and mutualism. They can be found in diverse environments worldwide, from tropical to polar regions, and play important roles in lichen ecology and biodiversity. Lichenicolous fungi are classified into several taxonomic groups, with the majority belonging to the Ascomycota and a smaller portion to the Basidiomycota. Their interactions with host lichens range from mild parasitism to severe pathogenicity, sometimes causing significant damage to lichen communities.
Briancoppinsia is a fungal genus in the family Arthoniaceae. It is monotypic, containing the single species Briancoppinsia cytospora, a lichenicolous fungus that parasitises parmelioid lichens, as well as Cladonia, Lepra, and Lecanora conizaeoides, among others. The species was first described scientifically by Léon Vouaux in 1914 as Phyllosticta cytospora.
Crittendenia is a genus of lichenicolous (lichen-dwelling) fungi in the monogeneric family Crittendeniaceae. The genus was circumscribed in 2021 to contain two species, C. lichenicola, and the type, C. coppinsii; these species were previously classified in the genus Chionosphaera. An additional 16 species were added to the genus the following year. The genus name honours British lichenologist Peter Crittenden.
Reichlingia is a genus of lichen-forming fungi in the family Arthoniaceae. It has seven species. The genus was originally circumscribed by Paul Diederich and Christoph Scheidegger in 1996, with Reichlingia leopoldii as the type, and at that time, only species. The fungus was at first thought to be a lichenicolous (lichen-dwelling) fungus, but is now considered a lichenised hyphomycete.
Baidera is a single-species fungal genus in the family Roccellaceae. It contains the species Baidera mauritiana, a corticolous (bark-dwelling), crustose lichen found in Mauritius. Both the genus and species were described as new to science in 2020 by Paul Diederich and Damien Ernst. The genus name honours Cláudia Baider, curator of the Mauritius Herbarium.
Tremella anaptychiae is a species of lichenicolous (lichen-dwelling) fungus in the family Tremellaceae. It was first reported in the literature in 1996 by mycologist Paul Diederich, who did not formally describe it as a new species due to the paucity of material. Additional material was collected in later years, and it was finally described in 2017 by Juan Carlos Zamora and Diederich. The fungus is known to occur in Italy, Macedonia, Spain, and Sweden. It is confined to the host lichen Anaptychia ciliaris, which has a largely palearctic distribution.
Tremella imshaugiae, is a lichenicolous (lichen-dwelling) fungus that is parasitic on the lichen Imshaugia aleurites. It is a species of Basidiomycota belonging to the family Tremellaceae.
Amerosporiopsis phaeographidis is a species of lichenicolous fungus in the subphylum Pezizomycotina. It grows as black spots on the lichen Phaeographis brasiliensis, from which it gets its name. It has only been found in one place in the Fakahatchee Strand Preserve State Park in Florida in the United States. Molecular phylogenetics testing might reveal that this is actually a new genus, but it is morphologically similar to the one other species in Amerosporiopsis, except that it has wider conidia, has no conidiophores, and lives in a different habitat.
Tremella parmeliarum is a species of lichenicolous (lichen-dwelling) fungus in the family Tremellaceae. Its host is the foliose lichen species Parmotrema reticulatum.
Syzygospora is a genus of fungi in the family Filobasidiaceae. Circumscribed by the American mycologist George Willard Martin in 1937, the genus is characterized by its gelatinous fruiting bodies that often form galls on host organisms. Syzygospora species possess distinctive features such as thin-walled hyphae with clamp connections, haustorial branches, and a hymenium containing probasidia that develop into elongated, club-shaped basidia. The genus has undergone taxonomic revisions, including the synonymization of Christiansenia and the transfer of some lichenicolous (lichen-dwelling) species to the newly established genus Zyzygomyces. As of 2024, the genus comprises 13 accepted species.
Chionosphaera is a genus of fungi in the family Chionosphaeraceae. It has four species.
Biatoropsis usnearum is a species of parasitic fungus that grows exclusively on lichen species of the genus Usnea, particularly U. subfloridana, U. barbata, and U. florida. First described in 1934 by Veli Räsänen, it has become a significant model organism in fungal evolution studies due to its specialised host relationships. The fungus belongs to the order Tremellales, though its precise family classification remains uncertain. It forms distinctive swellings or galls on its host lichens, ranging in colour from pale pink to dark reddish-brown, and notably suppresses the production of host defensive compounds like usnic acid. While initially misclassified due to its unusual characteristics, modern microscopic and genetic studies have revealed it to be part of a species complex, with at least three additional species now recognised. Found across Europe and North America, B. usnearum preferentially infects young, growing parts of its host lichens, particularly branch tips and small branches. The species has become particularly important in understanding how parasitic fungi adapt to new hosts, as it demonstrates evolution through switching between different host species rather than evolving alongside a single host species over time.