''Crespoa'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of five species of

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

in the 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'' ( 82 ...

. Species in this genus are characterized by having an upper

thallus Thallus (: 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. A thallus usually names the entir ...

surface that is wrinkled and reticulately ridged to coarsely foveolate (having small pits or depressions).

Description

''Crespoa'' species have a distinctive

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 Protocetraric acid is a chemical compound with the molecular formula . It is a secondary metabolite produced by a variety of lichens and is classified as a depsidone. History In 1845 Knop and Schnedermann isolated crystalline cetraric acid fro ...

Distribution

All of the species in ''Crespoa'' have a more or less

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

distribution, although the range of ''C. carneopruinata'' also extends into southern France and Italy, while the distribution of the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

''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 Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

of their vegetative

. This group was placed in ''

Pseudoparmelia ''Pseudoparmelia'' is a genus of lichen-forming fungi in the family Parmeliaceae. The genus has a pantropical distribution. Taxonomy It was circumscribed by Bernt Arne Lynge in 1914, who distinguished the genus from '' Parmelia'' by the presen ...

'' by

Mason Hale Mason Ellsworth Hale, Jr. (September 23, 1929 – April 23, 1990) was one of the most prolific American lichenologists of the 20th century. Many of his scholarly articles focused on the taxonomy of the family Parmeliaceae. Hale was one of the fi ...

in 1976, and then later in '' Canoparmelia''. 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 biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

clade that is

sister A sister is a woman or a girl who shares parents or a parent with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to ref ...

to a clade containing members of the genus ''

Parmotrema ''Parmotrema'' is a genus of lichen belonging to the family Parmeliaceae. It is a large genus, containing an estimated 300 species, with a centre of diversity in subtropical regions of South America and the Pacific Islands. Members of the genus ...

'', 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 Mu ...

formally defined ''Parmotrema''

subgenus In biology, a subgenus ( 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 the ge ...

''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 Genetic distance is a measure of the genetics, genetic divergence between species or between population#Genetics, populations within a species, whether the distance measures time from common ancestor or degree of differentiation. Populations with ...

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, thymine, cytosine, and guanine. The ...

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 Int ...

, "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'' (Zahlbr.) Lendemer & B.P.Hodk. (2013) *'' Crespoa crozalsiana'' (B.de Lesd. ex Harm.) Lendemer & B.P.Hodk. (2013) *'' Crespoa inhaminensis'' (C.W.Dodge) Lendemer & B.P.Hodk. (2013) *'' Crespoa schelpei'' (Hale) Lendemer & B.P.Hodk. (2013) *'' Crespoa scrobicularis'' (Kremp.) Benatti & Lendemer (2014)

References

{{Taxonbar, from=Q21216506 Parmeliaceae Lecanorales genera Lichen genera Taxa described in 2011 Taxa named by David Leslie Hawksworth