Historical biogeography of Melastomataceae: The roles of tertiary migration and long-distance dispersal

Melastomataceae and Memecylaceae are pantropically distributed sister group s for which an ndhF gene phylogeny for 91 species in 59 genera is here link ed with Eurasian and North American fossils in a molecular clock approach t o biogeographical reconstruction. Nine species from the eight next-closest families are used to root phylogenetic trees obtained under maximum likelih ood criteria. Melastomataceae comprise similar to 3000 species in the neotr opics, similar to 1000 in tropical Asia, 240 in Africa, and 225 in Madagasc ar in 150-166 genera, and the taxa sampled come from throughout this geogra phic range. Based on fossils, ranges of closest relatives, tree topology, a nd calibrated molecular divergences, Melastomataceae initially diversified in Paloecene/Eocene times In tropical forest north of the Tethys. Their ear liest (Eocene) fossils are from northeastern North America, and during the Oligocene and Miocene melastomes occurred in North America as well as throu ghout Eurasia. They also entered South America, with earliest (Oligocene) S outh American fossils representing Merianieae. One clade (Melastomeae) reac hed Africa from the neotropics 14-12 million years ago and from there sprea d to Madagascar, India, and Indochina. Basalmost Melastomataceae (Kibessiea e, Astronieae) are species-poor lineages restricted to Southeast Asia. Howe ver, a more derived Asian clade (Sonerileae/Dissochaeteae) repeatedly reach ed Madagascar and Africa during the Miocene and Pliocene. Contradicting ear lier hypotheses, the current distribution of Melastomataceae is thus best e xplained by Neogene long-distance dispersal, not Gondwana fragmentation.