''Zwackhiomacromyces'' is a

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 ...

of lichenicolous (

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

in the family

Xanthopyreniaceae Xanthopyreniaceae is a family of lichen-forming fungi in the order Collemopsidiales. The family was circumscribed by lichenologist Alexander Zahlbruckner Alexander Zahlbruckner (31 May 1860, Svätý Jur – 1938, Vienna) was an Austrian- H ...

. 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 "ostium", "opening". The term is also used in higher plants, for example to denote the opening of the involuted ...

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 or ...

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

Taxonomy

The genus was

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

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

type species In 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 species that contains the biological type specimen ...

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

Description

''Zwackhiomacromyces'' has black, pear-shaped ascomata (), which are fungal reproductive structures. These ascomata 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 colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

. 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 microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissues), in cytology (microscopic study of cells), and in the ...

with

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

. The

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

(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 may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

and typically have three

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five coun ...

(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 el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

(translucent) and smooth-walled, lacking any subapical germ pore-like spot. ''Zwackhiomacromyces'' is closely related to and often compared with '' Zwackhiomyces'', 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 for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ...

. 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 ''Zwackhiomyces'' is a genus of lichenicolous fungi in the family Xanthopyreniaceae. The genus was circumscribed by Martin Grube and Josef Hafellner in 1990, with '' Zwackhiomyces coepulonus'' assigned as the type species. The genus name of ''Zw ...

'' 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