Parallel bursts of recent and rapid radiation in the Mediterranean and Eritreo-Arabian biodiversity hotspots as revealed by Globularia and Campylanthus (Plantaginaceae)

作者：Affenzeller Matthias; Kadereit Joachim W; Comes Hans Peter^*

来源：Journal of Biogeography, 2018, 45(3): 552-566.

DOI：10.1111/jbi.13155

• ancestral area reconstructions
• Campylanthus
• dispersal
• diversification rates
• Eritreo-Arabia
• Globularia
• Mediterranean
• molecular phylogenetics
• palaeoclimate
• vicariance

Aim: Molecular phylogenetic inferences have been important to test hypotheses of the temporal and geographical origin of plant lineages from the Mediterranean region (MR) and their rates of diversification. However, comparisons are still rare between well-sampled and closely related clades from within and outside the MR. Here, we compare the biogeographical histories and diversification rates between two main genera of woody perennial Plantaginaceae with highest species diversities in the MR (Globularia) and the Eritreo-Arabian region (EAR; Campylanthus).
Location: Mediterranean Basin and adjacent regions; Eritreo-Arabian region.
Methods: We estimated a time-calibrated phylogeny of the Globularia+Poskea-Campylanthus clade based on combined nuclear (ITS) and chloroplast DNA sequences for ancestral area reconstructions and within- and among-clade diversification rate analyses.
Results: The presently disjunct ranges between Globularia and Campylanthus most likely reflect dispersal/migration from the EAR into the MR between the mid-early Miocene (c.9.6Ma) and the late Pliocene (c.3.3Ma). The subsequent diversification of Globularia coincides with that of Campylanthus (c.3.5Ma), with similar rates of constant lineage accumulation in both genera. While the Macaronesian Globularia species are recent (Late Pleistocene) colonists, most likely from the MR, neither late Plio-/Pleistocene vicariance nor dispersal-mediated range evolution can be refuted for Macaronesian versus EAR Campylanthus.
Main conclusions: The coupling between low- and high-latitude climate shifts likely triggered the simultaneous diversification at comparable rates of Campylanthus and Globularia in, respectively, the EAR and MR at the end of the Pliocene. In the extensive and ecogeographically complex MR, Globularia experienced increased diversification rates likely triggered by glacial cycles and resulting in adaptive species formation. In contrast, increased diversification rates in Campylanthus likely were triggered by aridity cycles and resulted in geographical speciation.

• 出版日期2018-3