Historical biogeography and phenotype‐phylogeny ofChroodiscus(lichenized Ascomycota: Ostropales: Graphidaceae)

Abstract

Aim To analyse the historical biogeography of the lichen genus Chroodiscus using a phenotype-based phylogeny in the context of continental drift and evolution of tropical rain forest vegetation.Location All tropical regions (Central and South America, Africa, India, Southeast Asia, north-east Australia).Methods We performed a phenotype-based phylogenetic analysis and ancestral character state reconstruction of 14 species of the lichen genus Chroodiscus, using paup* and mesquite; dispersal-vicariance analysis (DIVA) and dispersalextinction-cladogenesis (DEC) modelling to trace the geographical origin of individual clades; and ordination and clustering by means of pc-ord, based on a novel similarity index, to visualize the biogeographical relationships of floristic regions in which Chroodiscus occurs. ResultsThe 14 species of Chroodiscus show distinctive distribution patterns, with one pantropical and one amphi-Pacific taxon and 12 species each restricted to a single continent. The genus comprises four clades. DIVA and DEC modelling suggest a South American origin of Chroodiscus in the mid to late Cretaceous (120-100 Ma), with subsequent expansion through a South American-AfricanIndian-Southeast Asian-Australian dispersal route and late diversification of the argillaceus clade in Southeast Asia. Based on the abundance of extant taxa, the probability of speciation events in Chroodiscus is shown to be extremely low. Slow dispersal of foliicolous rain forest understorey lichens is consistent with estimated phylogenetic ages of individual species and with average lengths of biological species intervals in fungi (10-20 Myr). Main conclusionsThe present-day distribution of Chroodiscus can be explained by vicariance and mid-distance dispersal through the interconnection or proximity of continental shelves, without the need for recent, trans-oceanic long-distance dispersal. Phylogenetic reconstruction and age estimation for Chroodiscus are consistent with the 'biotic ferry' hypothesis: a South American origin and subsequent eastward expansion through Africa towards Southeast Asia and north-eastern Australia via the Indian subcontinent. The present-day pantropical distributions of many clades and species of foliicolous lichens might thus be explained by eastward expansion through continental drift, along with the evolution of modern rain forests starting 120 Ma, rather than by the existence of a hypothetical continuous area of premodern rain forest spanning South America, Africa and Southeast Asia during the mid and late Cretaceous.

New species and new records of thelotremoid Graphidaceae (Ascomycota: Ostropales) from Thailand

“…Recent surveys focusing on the Neotropics have unveiled a large number of new species of microlichens, while the Paleotropics are less well known. Especially tropical forests harbour high diversity of Graphidaceae (Lücking et al 2008;Lücking et al 2009;Rivas Plata et al 2008;Rivas Plata et al 2010;Weerakoon et al 2012a;Weerakoon et al 2012b).…”

Population genetics of lichen-forming fungi – a review

“…Thirdly, molecular phylogeography (see glossary, Appendix 1) (Avise et al 1987) analyses the genetic structure of species on a range-wide scale, and can be used to infer population history Palice & Printzen 2004;Buschbom 2007;Lücking et al 2008), to localize refugia (Dépraz et al 2008), and to identify migration routes (Hewitt 1996;Taberlet et al 1998;Hewitt 1999Hewitt , 2000.…”

Remototrachyna, a newly recognized tropical lineage of lichens in the Hypotrachyna clade (Parmeliaceae, Ascomycota), originated in the Indian subcontinent

“…Lichen biogeography has recently become a dynamic field of study in which distribution patterns are analyzed in a phylogenetic framework (Printzen and Lumbsch, 2000; Crespo et al, 2002; Högberg et al, 2002; Printzen and Ekman, 2002; Arnerup et al, 2004), using statistical methods to address ancestral range evolution of clades (Lücking et al, 2008a). Lichen‐forming fungi have generally larger distribution ranges than most vascular plants with numerous cosmopolitan or pantropical species (Culberson, 1972b; Crespo et al, 2002; Printzen and Ekman, 2002; Feuerer and Hawksworth, 2007).…”