Details

Autor(en) / Beteiligte

• Trénel, Philipp
• Gustafsson, Mats H.G.
• Baker, William J.
• Asmussen-Lange, Conny B.
• Dransfield, John
• Borchsenius, Finn

Titel

Mid-Tertiary dispersal, not Gondwanan vicariance explains distribution patterns in the wax palm subfamily (Ceroxyloideae: Arecaceae)

Ist Teil von

• Molecular phylogenetics and evolution, 2007-10, Vol.45 (1), p.272-288

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2007

Quelle

MEDLINE

Beschreibungen/Notizen

• The Ceroxyloideae is a small but heterogeneous subfamily of palms (Arecaceae, Palmae). It includes a Caribbean lineage (tribe Cyclospathae), a southern hemisphere disjunction (tribe Ceroxyleae), and an amphi-Andean element (tribe Phytelepheae), until recently considered a distinct subfamily (Phytelephantoideae) due to its highly derived morphology. A variety of hypotheses have been proposed to account for the biogeography of the subfamily, involving Gondwanan vicariance, austral interplate dispersal from South America to Australia via Antarctica, Andean orogeny, and Pleistocene refuges. We assessed the systematic classification and biogeography of the group based on a densely sampled phylogeny using >5.5 kb of DNA sequences from three plastid and two nuclear genomic regions. The subfamily and each of its three tribes were resolved as monophyletic with high support. Divergence time estimates based on penalized likelihood and Bayesian dating methods indicate that Gondwanan vicariance is highly unlikely as an explanation for basic disjunctions in tribe Ceroxyleae. Alternative explanations include a mid-Tertiary trans-Atlantic/trans-African dispersal track and the “lemurian stepping stones” hypothesis. Austral interplate dispersal of Oraniopsis to Australia could have occurred, but apparently only in the mid-Eocene/early Oligocene interval after global cooling had begun. Our data do not support Pleistocene climatic changes as drivers for speciation in the Andean-centered Phytelepheae as previously proposed. Radiation in this tribe coincides largely with the major uplift of the Andes, favoring Andean orogeny over Pleistocene climatic changes as a possible speciation-promoting factor in this tribe.