''Biatoropsis'' is a

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 ...

of lichenicolous (

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

-dwelling)

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

of uncertain familial placement in the order

Tremellales 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 ...

. It comprises 11 species that

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 ...

various species in the

fruticose lichen A fruticose lichen is a form of lichen fungi that is characterized by a coral-like shrubby or bushy growth structure. It is formed from a symbiotic relationship of a photobiont such as green algae or less commonly cyanobacteria and one, two or m ...

genera ''

Usnea ''Usnea'' is a genus of fruticose lichens in the large family Parmeliaceae. The genus, which currently contains roughly 130 species, was established by Michel Adanson in 1763. Species in the genus grow like leafless mini-shrubs or tassels anch ...

'' and '' Protousnea''.

Taxonomy

The genus 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 1935 by the Finnish lichenologist

Veli Räsänen Veli Johannes Paavo Bartholomeus Räsänen (24 August 1888 – 16 July 1953) was a Finnish lichenologist who made contributions to the study and documentation of Nordic and Baltic lichen funga. As a lecturer at various agricultural institution ...

, who assigned '' Biatoropsis usnearum'' 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 genus remained

monospecific In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

for several decades, until research, starting in the 1990s, showed that ''B. usnearum'' represented a

species complex 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 ...

. Since then another ten species have been added to the genus.

Description

''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. At a microscopic level, the internal tissue (

context In semiotics, linguistics, sociology and anthropology, context refers to those objects or entities which surround a ''focal event'', in these disciplines typically a communicative event, of some kind. Context is "a frame that surrounds the event ...

) consists of thread-like cells called

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 that lack specialised connecting structures known as

clamps Clamp may refer to: Tools and devices *Brick clamp, an early method of baking bricks *Clamp (tool), a device or tool used to hold objects in a fixed relative position (many types listed) **C-clamp **C-clamp (stagecraft) **Riser clamp, a device u ...

. The fungus penetrates its host using specialised feeding structures called

haustoria In botany and mycology, a haustorium (plural haustoria) is a rootlike structure that grows into or around another structure to absorb water or nutrients. For example, in mistletoe or members of the broomrape family, the structure penetrates th ...

, which have a distinctive twisted or convoluted form characteristic of the

order of fungi. The reproductive surface (

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...

) 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. When fully mature, the spore-producing cells (

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

) are club-shaped to almost cylindrical and divided by cross-walls (

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 ...

). These cells develop extensions called epibasidia that are roughly cylindrical in shape. The spores (

basidiospore A basidiospore is a reproductive spore produced by basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid Ploidy () is the number of complete sets of chromos ...

s) they produce are nearly spherical to elliptical in shape and have a distinctive side projection called an apiculus. When these spores

germinate Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an flowering plant, angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the sp ...

, they do so by producing a tube-like growth. The fungus can also reproduce asexually in several ways. It commonly produces chains of spores called catenulate

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 ...

. 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. All species in the genus parasitise species of the

genera ''

'' and '' Protousnea'', causing

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...

s in infected species.

Species

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 ...

(in the

Catalogue of Life The Catalogue of Life (CoL) is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxono ...

) accepts 11 species of Biatoropsis: *'' Biatoropsis angulatae'' *'' Biatoropsis antarcticae'' *'' Biatoropsis hafellneri'' *'' Biatoropsis hirtae'' *'' Biatoropsis macaronesica'' *'' Biatoropsis millanesiana'' *'' Biatoropsis minuta'' *'' Biatoropsis nigrescens'' *'' Biatoropsis protousneae'' *'' Biatoropsis rubicundae'' *'' Biatoropsis usnearum''

References

{{Taxonbar, from=Q10429310 Tremellomycetes Basidiomycota genera Lichenicolous fungi Taxa named by Veli Räsänen Taxa described in 1934