Phylogeny and historical biogeography of the cocosoid palms (Arecaceae, Arecoideae, Cocoseae) inferred from sequences of six WRKY gene family loci.

Arecaceae tribe Cocoseae is the most economically important tribe of palms, including both coconut and African oil palm. It is mostly represented in the Neotropics, with one and two genera endemic to South Africa and Madagascar, respectively. Using primers for six single copy WRKY gene family loci, we amplified DNA from 96 samples representing all genera of the palm tribe Cocoseae as well as outgroup tribes Reinhardtieae and Roystoneae. We compared parsimony (MP), maximum likelihood (ML), and Bayesian (B) analysis of the supermatrix with three species-tree estimation approaches. Subtribe Elaeidinae is sister to the Bactridinae in all analyses. Within subtribe Attaleinae, Lytocaryum, previously nested in Syagrus, is now positioned by MP and ML as sister to the former, with high support; B maintains Lytocaryum embedded within Syagrus. Both MP and ML resolve Cocos as sister to Syagrus; B positions Cocos as sister to Attalea. Bactridineae is composed of two sister clades, Bactris and Desmoncus in one, for which there is morphological support, and a second comprising Acrocomia, Astrocaryum, and Aiphanes. Two B and one ML gene tree-species estimation approaches are incongruent with the supermatrix in a few critical intergeneric clades, but resolve the same infrageneric relationships. The biogeographic history of the Cocoseae is dominated by dispersal events. The tribe originated in the late Cretaceous in South America. Evaluated together, the supermatrix and species tree analyses presented in this paper provide the most accurate picture of the evolutionary history of the tribe to date, with more congruence than incongruence among the various methodologies.

Molecular phylogenetics of the palm subtribe Ptychospermatinae (Arecaceae).

PREMISE OF THE STUDY: We examined the phylogeny and intergeneric relationships among the 12 genera of the palm subtribe Ptychospermatinae. While many of these taxa are familiar, cultivated ornamental palms in warm areas of the world, the monophyly of the subtribe and its component genera required testing. We also examined the biogeographic relationships of this lineage, which has a significant radiation east of Wallace's Line. METHODS: Phylogenetic analyses were based on maximum parsimony and Bayesian analyses of nucleotide sequences of two low-copy nuclear genes: intron 4 of phosphoribulokinase and intron 23 of RNA polymerase II. Biogeographical reconstructions were explored using S-DIVA. KEY RESULTS: The two-gene, combined analysis yielded a monophyletic subtribe with six major clades. The biogeographical analysis suggests that the subtribe originated in New Guinea. CONCLUSIONS: The phylogenetic hypotheses support the monophyly of the subtribe. The genera Drymophloeus, Ponapea, and Veitchia, as presently circumscribed, are not monophyletic. The resurrection and expanded circumscription of the genus Ponapea are supported. A newly discovered species of Adonidia is confirmed as sister species to Adonidia merrillii. Our phylogenetic hypothesis suggests that the Ptychospermatinae diverged into six major clades with repeated radiations into Australia and the western Pacific. The presence of Adonidia to the west of Wallace's Line is likely to be the result of long-distance dispersal. The following new combinations are made to restore monophyly to Veitchia and Ponapea: Veitchia pachyclada, V. subisticha, V. lepidota, and Ponapea hentyi.