''Listerella paradoxa'' is a

slime mould Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms with a life cycle that includes a free-living single-celled stage and the formation of spores. Spores are often produced in macroscopic mu ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

from the

class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differentl ...

Myxogastria Myxogastria/Myxogastrea (myxogastrids, International Code of Zoological Nomenclature, ICZN) or Myxomycetes (International Code of Nomenclature for algae, fungi, and plants, ICN), is a Class (biology), class of slime molds that contains 5 o ...

and the only member of its

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

as well as the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Listerelliidae. The species is so far only found on the wattle genus ''

Cladonia ''Cladonia'' is a genus of moss-like lichens in the family Cladoniaceae. They are the primary food source for reindeer/caribou. ''Cladonia'' species are of economic importance to reindeer-herders, such as the Sami in Scandinavia or the Nenets ...

'', mostly in European temperate zones.

Characteristics

The

sporangia A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cy ...

are just 0.1 to 0.3 mm large, visible to the unaided eye as mere black-brown dots. The dehiscence lines are slightly lighter and clearly visible. They are unstiped, more or less hemispheric and flattened on the edge. The single layered

peridium The peridium is the protective layer that encloses a mass of spores in fungi. This outer covering is a distinctive feature of gasteroid fungi. Description Depending on the species, the peridium may vary from being paper-thin to thick and rubber ...

is tearing in four to six lobes during spore maturity and is purple-brown. It features dark lime tubercles only on the dehiscence lines. A

capillitium Capillitium (pl. capillitia) is a mass of sterile fibers within a fruit body interspersed among spores. It is found in Mycetozoa (slime molds) and gasteroid fungi of the fungal subdivision Agaricomycotina The subdivision Agaricomycotina, also kn ...

is less developed and is composed of pale purple-brown, slim, vermiculated strands, which are overgrown on the peridia. On low magnification, the 1 to 1.5

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

thick strands look like string of pearls. On high magnification, there are from the centre of the strand on cup or pear-shaped links visible, which thickenings are slightly darker on the blunted end, but the stipes are sallow. The link becomes gradually developed near the edge. The strand is first twice as thick as the normal dark-coloured one, then constrictions appear on them. Then, the constrictions become apparent on them, which arrange it into light stipes and knots, become little by little slimmer and take the shape of a cup. Alternatively, the strand is lighter coloured from the beginning on and the knots rapidly develop from the collar-like constrictions. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s are black-brown as spore mass and in transmitted light brownish yellow. They are on one side thin-walled, blur finely acanthoid and have a diameter from 7 to 8 µm.

Habitat

''Listerella paradoxa'' has been only found living on the thallae of the ''Cladonia'' species of

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Cladonia rangiferina ''Cladonia rangiferina'', also known as reindeer cup lichen, reindeer lichen (cf. Swedish language, Sw. ''renlav'') or grey reindeer lichen, is a light-colored fruticose lichen, fruticose, Cladonia, cup lichen species in the family Cladoniaceae. ...

'', '' Cladonia impexa'', ''

Cladonia arbuscula ''Cladonia arbuscula'' or the shrubby cup lichen is a species of cup lichen in the Cladoniaceae The Cladoniaceae are a family of lichenized fungi in the order Lecanorales. It is one of the largest families of lichen-forming fungi, with about 5 ...

'', '' Cladonia gracilis'', '' Cladonia tenuis''), in temperate zones mainly in Europe (Germany, Sweden, Denmark, Great Britain) but also partially in Russia and Canada. A collection from California is classified as uncertain.

Classification

The species and genus were first described in 1906 by Eduard Adolf Wilhelm Jahn on the basis of a discovery in

Geesthacht Geesthacht () is the largest city in the District of the Duchy of Lauenburg (Herzogtum Lauenburg) in Schleswig-Holstein in Northern Germany, south-east of Hamburg on the right bank of the River Elbe. History A church was built in what is today ...

. Its exact taxonomic position was unclear from the beginning and is still uncertain. Jahn grouped it into a family because of its strands in the capillitium. In the first half of the 19th century however it was often grouped into the Dianemaceae, and at later times often into the Liceaceae because of the relationship. The genus name of ''Listerella'' is in honour of Arthur Hugh Lister (1830–1908), who was an English wine merchant and botanist, known for his research on

Mycetozoa Mycetozoa is a polyphyletic grouping of slime molds. It was originally thought to be a monophyletic clade, but recently it was discovered that protostelia are a polyphyletic group within Conosa. Classification It can be divided into dictyostelid ...

References

{{Taxonbar, from=Q1864927 Myxogastria