title: Journey from the West: did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast?
abstract: OBJECTIVE
  This study elucidates the phylogenetic position of a unique taxon of Graphidaceae occurring on rock in coastal desert areas, assessing its importance for our understanding of the evolution of the largest family of tropical lichenized fungi. •
  
  
  METHODS
  We used maximum likelihood and Bayesian approaches to reconstruct a three-gene phylogeny of Graphidaceae and a Bayesian molecular clock approach to estimate divergence dates for major clades, as well as Bayesian ancestral ecogeography state analysis. •
  
  
  RESULTS
  The new genus Redonographa represents a new subfamily, Redonographoideae, sister to subfamily Graphidoideae. Redonographa is exclusively saxicolous and restricted to the American Pacific coast from California to central Chile, including Galapagos. It contains four species: Redonographa chilensis comb. nov., R. saxiseda comb. nov., R. saxorum comb. nov., and R. galapagoensis sp. nov. The genus Gymnographopsis, with a similar ecogeography but differing in excipular carbonization and chemistry, is also included in Redonographoideae, with the species G. chilena from Chile and G. latispora from South Africa. Molecular clock analysis indicates that Redonographoideae diverged from Graphidoideae about 132 million years ago (Ma) in the Early Cretaceous. •
  
  
  CONCLUSIONS
  The divergence date for subfamilies Redonographoideae and Graphidoideae coincides with the early breakup of Gondwana and ancient origin of the Atacama Desert. However, the common ancestor of Redonographoideae plus Graphidoideae was reconstructed to be tropical-epiphytic. Thus, even if Redonographoideae is subtropical-saxicolous, the hypothesis that Graphidoideae evolved from a subtropical-saxicolous ancestor is not supported.
authors.affiliation: Department of Botany, The Field Museum, 1400 South Lake Shore Drive, Chicago, IL 60605 USA. rlucking@fieldmuseum.org
authors.forename: Robert
authors.initials: R
authors.lastname: Lücking
authors.forename: Anders
authors.initials: A
authors.lastname: Tehler
authors.forename: Frank
authors.initials: F
authors.lastname: Bungartz
authors.forename: Eimy
authors.initials: E
authors.lastname: Rivas Plata
authors.forename: H Thorsten
authors.initials: HT
authors.lastname: Lumbsch
mesh_terms: D001203:Ascomycota / Q000145:classification* / Q000235:genetics*; D005075:Biological Evolution; D003710:Demography; D008011:Lichens; D015493:Paraparesis, Tropical Spastic; D010802:Phylogeny; D014481:United States
keywords: Graphidaceae; Mediterranean regions; Ostropales; Pacific Desert; Sonoran Desert; lichens; rock-inhabiting