Conserved genomic collinearity as a source of broadly applicable, fast evolving, markers to resolve species complexes: A case study using the lichen-forming genus Peltigera section Polydactylon.

•Intergenic spacers in syntenic regions (COR) are proposed for phylogenetic studies.•COR performance was compared to five loci commonly used in fungal phylogenetics.•Contribution to species delimitation and validation methods was also compared.•High cryptic diversity (29 new species) was revealed in one section of Peltigera.•125 collinear syntenic regions found across Lecanoromycetes and Eurotiomycetes.