Biogeography of Cedrela (Meliaceae, Sapindales) in Central and South America.

Dated phylogenies have helped clarify the complex history of many plant families that today are restricted to the world's tropical forests, but that have Eocene, Oligocene, and Miocene fossils from the northern hemisphere. One such family is the Meliaceae. Here we infer the history of the neotropical Meliaceae genus (17 species), the sister clade of which today is restricted to tropical Asia. Sequences from the nuclear ribosomal spacer region and five plastid loci obtained for all ingroup species and relevant outgroups were used to infer species relationships and for molecular‐clock dating under two Bayesian relaxed clock models. The clock models differed in their handling of rate autocorrelation and sets of fossil constraints. Results suggest that (1) crown group diversification in started in the Oligocene/Early Miocene and intensified in the Late Miocene and Early Pliocene, and (2) Central American species do not form a clade, implying reentry into Central America after the closure of the Panamanian Isthmus. At present, is distributed in both dry and humid habitats, but morphological features suggest an origin in dry forest under seasonal climates, fitting with Miocene and Pliocene fossils from deciduous forests.