''Rusavskia'' is a genus 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.fungi in the family Teloschistaceae. It has 12 species. It is a member of the subfamily Xanthorioideae. The thallus of ''Rusavskia'' is characterized by its foliose (leaf-like) structure with distinct and typically narrow that curve outwards.

Taxonomy

The genus ''Rusavskia'' was proposed by lichenologists

Sergey Kondratyuk Sergey Yakovlevich Kondratyuk ( uk, Сергій Якович Кондратюк) (born 17 May 1959) is a Ukrainian botanist specialising in lichenology. His research deals with the taxonomy, floristics, ecology and geography of lichens and lic ...

and

Ingvar Kärnefelt Jan Eric Ingvar Kärnefelt (born 1944) is a Swedish lichenologist. Early life and education Kärnefelt was born in Gothenburg, Sweden in 1944. His initial goal in his higher-level studies at University of Cologne in 1966–1967 was to become ...

in 2003, with ''

Rusavskia elegans ''Rusavskia elegans'' (formerly ''Xanthoria elegans''), commonly known as the elegant sunburst lichen, is a lichenized species of fungus in the genus ''Rusavskia'', family Teloschistaceae. Recognized by its bright orange or red pigmentation, this ...

'' assigned as the type species. The initial circumscription of the genus relied predominantly on an evaluation of morphological, anatomical and chemical characteristics, with a notable absence of

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analysis. For this reason, the reception of the ''Rusavskia'' by lichenologists was initially met with cautious appraisal. As several molecular studies in the subsequent years showed, the ''Rusavskia elegans''-group occupies a separate

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

branch in the Teloschistaceae; the growing body of molecular evidence led to the acceptance of the genus ''Rusavskia''.

Description

''Rusavskia'' is characterized by its foliose (leaf-like) structure with distinct and typically narrow that curve outwards. These lobes often feature

pseudocyphella Pseudocyphellae (singular ''pseudocyphella'') are structures in lichens that appear as tiny pores on the outer surface (the cortex of the lichen. They are caused when there is a break in the cortex of the lichen, and the medullary hyphae extend t ...

e – tiny, white porous areas on the lichen's surface. The lichen adheres to surfaces using short, root-like structures called . Its reproductive structures, known as apothecia, are in form and display a noticeable orange hue. The produced 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 ...

in shape, and polardiblastic, with a moderately divided central region ( septa). Additionally, ''Rusavskia'' may possess , which are embedded reproductive structures, and produce ellipsoid-shaped (asexual spores). ''Rusavskia'' was distinguished from ''Xanthoria'' due to several unique characteristics. Unlike ''Xanthoria'', ''Rusavskia'' has a mesodermate cortex, which contrasts the earlier belief of it being . While it was believed to lack attachment organs, it was later found that species like ''R. elegans'' and ''R. sorediata'' have hapters, albeit short ones. The (asexual spores) of ''Rusavskia'' are primarily ellipsoid, with only a minority being , contrary to earlier descriptions. In terms of morphology, ''Rusavskia'' predominantly differs from ''Xanthoria'' by its narrower lobes. When compared to ''

Dufourea ''Dufourea'' is a genus of sweat bees in the family Halictidae. There are at least 160 described species in ''Dufourea''.Sharkey M.J. (2007). ''Phylogeny and Classification of Hymenoptera''."Phylogenetic relationships among superfamilies of Hym ...

'', ''Rusavskia'' stands out due to its narrow lobes that adhere more closely to surfaces. Although some experts hesitated to accept the distinct classification of ''Rusavskia'', genetic evidence firmly sets it apart from ''Xanthoria'' and other related groups.

Species

, Species Fungorum (in the Catalogue of Life) accepts 12 species of ''Rusavskia''. Rusavskia sorediata

* '' Rusavskia aspera'' * '' Rusavskia crassa'' * ''

Rusavskia dasanensis ''Rusavskia'' is a genus of lichen-forming fungi in the family Teloschistaceae. It has 12 species. It is a member of the subfamily Xanthorioideae. The thallus of ''Rusavskia'' is characterized by its foliose lichen, foliose (leaf-like) structu ...

'' * '' Rusavskia drevlyanica'' * '' Rusavskia ectaniza'' * ''

'' * '' Rusavskia granulifera'' * ''

Rusavskia hafellneri ''Rusavskia'' is a genus of lichen-forming fungi in the family Teloschistaceae. It has 12 species. It is a member of the subfamily Xanthorioideae. The thallus of ''Rusavskia'' is characterized by its foliose (leaf-like) structure with dis ...

'' * ''

Rusavskia indica ''Rusavskia indica'' is a species of both corticolous (bark-dwelling) and saxicolous (rock-dwelling) lichen in the family Teloschistaceae. Found in India, it was formally described as a new species in 2017 by lichenologists Sergey Kondratyuk ...

'' * '' Rusavskia indochinensis'' * '' Rusavskia sorediata'' * '' Rusavskia subfruticulosa'' * '' Rusavskia upretii''

References

{{Taxonbar, from=Q21215467 Teloschistales Teloschistales genera Lichen genera Taxa described in 2003 Taxa named by Ingvar Kärnefelt Taxa named by Sergey Kondratyuk