''Raesaenenia'' is a fungal

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 ...

in the large family

Parmeliaceae The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: '' Xanthoparmelia'' ( 822 ...

. It is a

monotypic 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 "unispec ...

genus, containing the single lichenicolous fungus ''Raesaenenia huuskonenii'', which parasitises lichens of genus ''

Bryoria ''Bryoria'' is a genus of lichenized fungi in the family Parmeliaceae. Many members of this genus are known as horsehair lichens. The genus has a widespread distribution, especially in boreal and cool temperate areas. Taxonomy ''Bryoria'' was c ...

'' in the Northern Hemisphere.

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 2015 by

David Leslie Hawksworth David Leslie Hawksworth (born 1946 in Sheffield, UK) is a British mycologist and lichenologist currently with a professorship in the Universidad Complutense de Madrid in Madrid, Spain and also a Scientific Associate of The Natural History Muse ...

, Carlos Boluda, and Hanna Lindgren. The generic name honours Finnish lichenologist

Veli Räsänen Veli Johannes Paavo Bartholomeus Räsänen (24 August 1888 – 16 July 1953) was a Finnish lichenologist. Early life and education Veli Räsänen was born on 24 August 1888 in Simo, Finland. Räsänen's brother was the linguist Martti Räsä ...

, who described 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 ...

as ''Phacopsis huuskonenii'' in 1948. 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 botanist Avi Johannes Huuskonen from Pielavesi (

North Savo North Savo (or Northern Savonia; fi, Pohjois-Savo; sv, Norra Savolax) is a region in eastern Finland. It borders the regions of South Savo, Central Finland, North Ostrobothnia, Kainuu, and North Karelia. Kuopio is the largest city in the regio ...

, Finland), where it was found on the

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

of the lichen now known as '' Bryoria implexa''. In 2017, Divakar and colleagues used a then-recently developed "temporal phylogenetic" approach to identify temporal bands for specific

taxonomic rank In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in an ancestral or hereditary hierarchy. A common system consists of species, genus, family (biology), family, order (biology), order, class (b ...

s in the family Parmeliaceae, suggesting that groups of species that diverged within the time window of 29.45–32.55 million years ago represent genera. They proposed to synonymize ''Raesaenenia'' with '' Protousnea'', because ''Raesaenenia'' originated relatively recently and fell under the timeframe threshold for genus level. This synonymy was not accepted by

Robert Lücking Robert Lücking (born 1964) is a German lichenologist. He is a leading expert on foliicolous lichens–lichens that live on leaves. Life and career Born in Ulm in 1964, Lücking earned both his master's (1990) and PhD degree (1994) at the Univer ...

in a later critical analysis of this technique for lichen systematics, who noted that "if taxonomy and classification are to reflect evolutionary history, then merging them into a single genus just because of the point in time they diverged is certainly not justified".

Description

''Raesaenenia'' is characterized by having an

ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

structurally similar to those of genus ''

Phacopsis ''Phacopsis'' is a genus of lichenicolous (lichen-dwelling) fungi. They are parasites of members of the large lichen family Parmeliaceae, of which they are also a member. Originally proposed by Edmond Tulasne in 1852 to contain 3 species, ''Ph ...

'', but with somewhat cylindrical

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

s that have thickened caps of wall tissue at each end. ''Raesaenenia huuskonenii'' grows on ''

'' species in the Northern Hemisphere. Infection by the fungus results in blackened branches that are geniculately deformed (i.e., bent at a sharp angle).

References

External links

Image of type specimen
from JSTOR Global Plants {{Taxonbar, from=Q110239765 Parmeliaceae Monotypic Lecanorales genera Taxa described in 2015 Taxa named by David Leslie Hawksworth Lichenicolous fungi