Origin and Diversification of Major Clades in Parmelioid Lichens (Parmeliaceae, Ascomycota) during the Paleogene Inferred by Bayesian Analysis

Abstract

There is a long-standing debate on the extent of vicariance and long-distance dispersal events to explain the current distribution of organisms, especially in those with small diaspores potentially prone to long-distance dispersal. Age estimates of clades play a crucial role in evaluating the impact of these processes. The aim of this study is to understand the evolutionary history of the largest clade of macrolichens, the parmelioid lichens (Parmeliaceae, Lecanoromycetes, Ascomycota) by dating the origin of the group and its major lineages. They have a worldwide distribution with centers of distribution in the Neo- and Paleotropics, and semi-arid subtropical regions of the Southern Hemisphere. Phylogenetic analyses were performed using DNA sequences of nuLSU and mtSSU rDNA, and the protein-coding RPB1 gene. The three DNA regions had different evolutionary rates: RPB1 gave a rate two to four times higher than nuLSU and mtSSU. Divergence times of the major clades were estimated with partitioned BEAST analyses allowing different rates for each DNA region and using a relaxed clock model. Three calibrations points were used to date the tree: an inferred age at the stem of Lecanoromycetes, and two dated fossils: Parmelia in the parmelioid group, and Alectoria. Palaeoclimatic conditions and the palaeogeological area cladogram were compared to the dated phylogeny of parmelioid. The parmelioid group diversified around the K/T boundary, and the major clades diverged during the Eocene and Oligocene. The radiation of the genera occurred through globally changing climatic condition of the early Oligocene, Miocene and early Pliocene. The estimated divergence times are consistent with long-distance dispersal events being the major factor to explain the biogeographical distribution patterns of Southern Hemisphere parmelioids, especially for Africa-Australia disjunctions, because the sequential break-up of Gondwana started much earlier than the origin of these clades. However, our data cannot reject vicariance to explain South America-Australia disjunctions.

Journey from the West: Did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast?

“…For example, the largest lichenized clade, Lecanoromycetes, has subclasses Acarosporomycetidae and Candelariomycetidae in a basal position, and these are commonly found in subtropical deserts on rock ( Hofstetter et al, 2007 ). Such evolutionary patterns are consistent with estimates that date Lecanoromycetes back to the warm Triassic ( Amo de Paz et al, 2011 ;E. Rivas Plata et al, unpublished manuscript ).…”

“…However, for extant lichenized lineages such as Arthoniomycetes, Lecanoromycetes, Lichinomycetes, Eremithallales, Trypetheliales, and Verrucariales in Ascomycota and Dictyonema , Lepidostroma , Lichenomphalia , Marchandomphalina , and Multiclavula in Basidiomycota, evidence points to a more recent, multiple origin of these from nonlichenized ancestors between 300 and 200 Ma ( Gargas et al, 1995 ;Lawrey et al, 2009 ;Nelsen et al, 2009Nelsen et al, , 2011Schoch et al, 2009 ). In the absence of a good fossil record, molecular clock dating studies indicate that most lichenized lineages, at least in the Ascomycota, evolved in the relatively dry, warm Triassic, during which extended terrestrial forest vegetation was sparsely developed ( Amo de Paz et al, 2011 ;E. Rivas Plata et al, unpublished manuscript ).…”

“…Ancestral ecogeographical character state reconstruction analysis -Ancestral ecogeographical character state reconstruction analysis was performed using a stochastic Bayesian approach to character mapping ( Huelsenbeck et al, 2003 ) implemented in SIMMAP 1.5 ( Bollback, 2006 ), as was done previously in biogeographical studies ( Lopez-Vaamonde et al, 2009 ;Amo de Paz et al, 2011 ). We treated the major ecogeographic regions as discrete characters, which were categorized broadly into three traits as multistate characters: wet tropical (0), wet extratropical (1), and semiarid to arid subtropical or "mediterranean" (2).…”

The adaptive radiation of lichen-forming Teloschistaceae is associated with sunscreening pigments and a bark-to-rock substrate shift

“…S1) suggest that the first split between the tropical suborder Letrouitineae and the rest of the Teloschistales dates back to 162 .84 Mya), in the Middle Jurassic when the climate was warm and arid (31). This divergence time overlaps with the split of another major lichen taxon, the Lecanorales (Lecanoromycetidae; 160.65 Mya) (32,33). The next divergence at ∼145 Mya (167.72-122.56 Mya), in the Early Cretaceous, gave rise to the families Megalosporaceae and Teloschistaceae, concurrent with a cooling trend, with seasonal snow and small ice caps in the poles (34,35 Increase in Diversification Rate Within the Teloschistales.…”

Hypotrachyna penduliloba and Remototrachyna pandani, two new species in the hyperdiverse lichen family Parmeliaceae from Réunion in the Mascarene Archipelago

“…It is a large, subcosmopolitan and very diverse family with 79 genera and over 2700 species currently recognized (Thell et al 2012), of which the basal radiation occured between 60 and 74 MA ago (Amo de Paz et al 2011). This group has been extensively studied worldwide by several researchers for more than five decades .…”