''Zwackhiomacromyces'' 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 ...

in the family

Xanthopyreniaceae Xanthopyreniaceae is a family (biology), family of lichen-forming fungi in the order Collemopsidiales. The family was circumscription (taxonomy), circumscribed by lichenologist Alexander Zahlbruckner in 1926. Genera This is a list of the genera ...

. It has two species. The genus is distinguished by its black, pear-shaped fruiting bodies () with large, nipple-shaped

ostiole An ''ostiole'' is a small hole or opening through which algae or fungi release their mature spores. The word is a diminutive of wikt:ostium, "ostium", "opening". The term is also used in higher plants, for example to denote the opening of the ...

s that have a surface, and a dark, multi-layered wall made up of

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 ...

l cells forming a structure. The genus is closely related to the similarly named genus ''

Zwackhiomyces ''Zwackhiomyces'' is a genus of lichenicolous fungus, lichenicolous (lichen-dwelling) fungi in the family Xanthopyreniaceae. Taxonomy The genus was circumscription (taxonomy), circumscribed by Martin Grube and Josef Hafellner in 1990, with ''Zw ...

''.

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 2014 by the lichenologists Javier Etayo and Pieter van den Boom, with ''Zwackhiomacromyces constrictocarpus'' assigned 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 ...

. A second species, '' Z. hyalosporus'', was transferred to the genus from '' Pyrenidium'' in 2016.

Description

''Zwackhiomacromyces'' has black, pear-shaped

ascomata An ascocarp, or ascoma (: ascomata), is the fruiting body (sporocarp (fungi), sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded ascus, asci, each of which typically contains four to ...

(), which are fungal reproductive structures. These

have relatively large, (nipple-shaped) ostioles—openings through which spores are released. The surface of these ostioles is and opens radially. The wall of the ascomata is dark and multi-layered, made up of

l cells that form a structure, with the outermost layer sometimes having extracellular

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

. The internal structure of the hymenium (the ) of these fungi is characterised by branching and interconnected , which are filamentous structures within the ascomata. However, they lack and , which are other types of filaments found in some fungi. The central part of the ascomata does not react to

staining Staining is a technique used to enhance contrast in samples, generally at the Microscope, microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissue (biology), tissues), in cytology (microscopic ...

with

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

. The asci (spore-producing cells) of ''Zwackhiomacromyces'' are elongated and club-shaped, with a thickened wall on the side and at the tip, where an ocular chamber is present. The ascospores are

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

and typically have three

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 ...

(internal partitions), though they can range from having two to three. These spores are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

(translucent) and smooth-walled, lacking any subapical

germ pore A germ pore is a small pore in the outer wall of a fungal spore through which the germ tube exits upon germination. It can be wikt:apical, apical or eccentric in its location, and, on light microscopy, may be visualized as a lighter coloured are ...

-like spot. ''Zwackhiomacromyces'' is closely related to and often compared with ''

'', a genus established in 1990 that comprises around 32 species. The species in this latter genus are characterised by their ascomata, branched and interconnected filaments between the asci, asci (having a two-layered wall that splits to release spores), and ascospores usually with a single

septum In biology, a septum (Latin language, Latin for ''something that encloses''; septa) is a wall, dividing a Body cavity, cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Hum ...

. While the genus is generally uniform in terms of its hamathecial structures, asci, and ascospores, variations do exist in some species, such as '' Zwackhiomyces lecanorae'' with its simple spores and '' Zwackhiomyces cervinae'', which features spores with a and a tendency to turn brown.

Species

* '' Zwackhiomacromyces constrictocarpus'' * '' Zwackhiomacromyces hyalosporus''

References

{{Taxonbar, from=Q60173867 Xanthopyreniaceae Dothideomycetes genera Lichenicolous fungi Taxa described in 2014 Taxa named by Javier Angel Etayo Salazar