''Didymocyrtis trassii'' is a species of lichenicolous (lichen-eating)

fungus 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 th ...

in the family

Phaeosphaeriaceae The Phaeosphaeriaceae are a family of fungi in the order Pleosporales. Species in the family have a cosmopolitan distribution, and are generally nectrotrophic or saprobic on a wide range of plants. Genera list *'' Barria'' *'' Bricookea'' *'' C ...

. It is found in southern Ukraine, where it parasitises the foliose lichen ''

Cetraria aculeata ''Cetraria aculeata'' or the spiny Iceland lichen is a dark brown to black fruticose, soil Iceland lichen from the family Parmeliaceae. The species was first described by German naturalist Johann Christian Daniel Edler von Schreber in 1771 unde ...

'' growing on sand dunes.

Taxonomy

The fungus was formally described as a new species in 2018 by

Ave Suija Ave Suija (born 16 April 1969) is an Estonian lichenologist. The lichenicolous fungus A lichenicolous fungus is a parasitic fungus that only lives on lichen as the host. A lichenicolous fungus is not the same as the fungus that is the component ...

, Valeriy Darmostuk, and Alexander Khodosovtsev. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

was collected by the third author between the between villages of Burkuty and Prominin in Hola Prystan Raion (

Kherson Oblast Kherson Oblast ( uk, Херсо́нська о́бласть, translit=Khersónsʹka óblastʹ, ), also known as Khersonshchyna ( uk, Херсо́нщина, ), is an oblast (province) in southern Ukraine, currently claimed and partly occupied ...

); there, it was found growing on the foliose lichen ''

'', which itself was growing in sand dunes. The species epithet honours Estonian lichenologist and botanist

Hans Trass Hans-Voldemar Trass (2 May 1928 – 14 February 2017) was an Estonian ecologist and botanist. He was a member of the Estonian Academy of Sciences since 1975 and president of the Estonian Naturalists' Society from 1964 to 1973 and 1985 to 1991. ...

Description

''Didymocyrtis trassii'' has pycnidial conidiomata of the ''

Phoma ''Phoma'' is a genus of common coelomycetous soil fungi. It contains many plant pathogenic species. Description Spores are colorless and unicellular. The pycnidia are black and depressed in the tissues of the host. ''Phoma'' is arbitrarily lim ...

''-type. The pycnidia are black and more or less spherical, and partially immersed in the host thallus. They are typically 70–100

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 ...

in diameter, with a wall that is 25–35 μm thick. The

conidia A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the ...

are 14.2–18.2 by 5.0–7.2 μm. A sexual stage for the fungus is not known.

Habitat and distribution

''Didymocyrtis trassii'' is only known to occur in southern Ukraine, and it only parasitises ''Cetraria aculeata'' growing on sand. The fungus grows on the lower branches of the thick cushions of the lichen, and does not appear to cause damage to the host.

References

{{Taxonbar, from=Q107635083 Phaeosphaeriaceae Fungi described in 2018 Fungi of Europe Lichenicolous fungi Taxa named by Ave Suija Fungus species