lichen
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Parmeliaceae. Species in this genus are characterized by having an upper thallus surface that is wrinkled and reticulately ridged to coarsely foveolate (having small pits or depressions).
Description
''Crespoa'' species have a distinctive thallus structure, with a strongly reticulately ridged and wrinkled upper surface, and medullary stictic and
constictic acid
Constictic acid is a chemical compound of the depsidone class. It was first isolated in 1968 from lichen of the genus ''Usnea''. It has since been found in many other lichen genera including ''Menegazzia'', '' Crespoa'', and ''Xanthoparmelia
...
s, with the exception of ''C. schelpei'', which has medullary protocetraric acid.
Distribution
All of the species in ''Crespoa'' have a more or less tropical distribution, although the range of ''C. carneopruinata'' also extends into southern France and Italy, while the distribution of the type species ''C. crozalsiana'' includes the US and southern Europe. ''C. scrobicularis'' has been reported from Oceania and South America, including Argentina, Brazil, Paraguay, and Venezuela.
Taxonomy
Species in ''Crespoa'' were originally considered part of the ''Parmelia crozalsiana'' group, united by similarities in the morphology of their vegetative thallus. This group was placed in ''
Pseudoparmelia
''Pseudoparmelia'' is a genus of lichenized fungi in the family Parmeliaceae. The genus has a pantropical distribution, and contains 27 species. It was circumscribed by Bernt Arne Lynge in 1914, who distinguished the genus from ''Parmelia'' by th ...
'' by
Mason Hale
Mason Ellsworth Hale, Jr. (September 23, 1929 – April 23, 1990) was one of the most prolific lichenologists of the 20th century. Many of his scholarly articles focused on the taxonomy of the family Parmeliaceae. Hale was one of the first liche ...
in 1976, and then later in ''
Canoparmelia
''Canoparmelia'' is a genus of lichen-forming fungi in the family Parmeliaceae. The widespread genus contains about 35 species. ''Canoparmelia'', a segregate of the parmelioid lichen genus ''Pseudoparmelia'', was circumscribed by John Elix and M ...
''. More recently,
molecular analysis
Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...
demonstrated that this group of four species forms a well-supported
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 ...
clade that is sister to a clade containing members of the genus '' Parmotrema'', and were therefore unsuitably classified as members of ''Canoparmelia''. For this reason,
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 ...
formally defined ''Parmotrema''
subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
''Crespoa'' to contain this group, suggesting "generic rank is not appropriate ... as there are no features from the ascomata or conidiomata that distinguish it ... from ''Parmotrema''." In a later analysis, this subgenus was promoted to status as a distinct genus, due to both differences in thallus morphology, and its significant genetic distance from ''Parmotrema''.
In 2014, Michel Benatti and James Lendemer proposed transferring ''Parmelia scrobicularis'' (also known as ''Pseudoparmelia scrobicularis'' and ''Canoparmelia scrobicularis'') to ''Crespoa'' based on its shared morphological and chemical characteristics, albeit without providing phylogenetic support. In 2016, Kirika and colleagues suggested that ''Crespoa'' should be subsumed within ''Parmotrema'', and treated as a subgenus, as per Hawksworth's proposal. In 2017, Michelin and colleagues confirmed the correct generic placement of ''Crespoa scrobicularis'' using molecular analysis, and also confirmed the monophyly of ''Crespoa''. An analysis of the phylogeny of the Parmeliaceae using a next-generation
DNA sequencing
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
technique (target enrichment sequencing) also supports accepting ''Crespoa'' at the genus level.
The genus name ''Crespoa'' honours Spanish lichenologist
Ana Crespo
Ana María Crespo de las Casas (born 30 March 1948, Santa Cruz de Tenerife) is a Spanish lichenologist noted for studying the phytosociology, taxonomy and floristics of Mediterranean lichens. She was awarded the 2012 Acharius Medal from the Intern ...
, "in recognition of the lead she has taken in rationalizing generic and specific concepts in the parmelioid lichens using molecular phylogenetic approaches."
Species
*''
Crespoa carneopruinata
''Crespoa'' is a genus of five species of lichen in the family Parmeliaceae. Species in this genus are characterized by having an upper thallus surface that is wrinkled and reticulately ridged to coarsely foveolate (having small pits or depres ...
'' (Zahlbr.) Lendemer & B.P.Hodk. (2013)
*''
Crespoa crozalsiana
''Crespoa'' is a genus of five species of lichen in the family Parmeliaceae. Species in this genus are characterized by having an upper thallus surface that is wrinkled and reticulately ridged to coarsely foveolate (having small pits or depressio ...
Crespoa schelpei
''Crespoa'' is a genus of five species of lichen in the family Parmeliaceae. Species in this genus are characterized by having an upper thallus surface that is wrinkled and reticulately ridged to coarsely foveolate (having small pits or depres ...