From Messinian crisis to Mediterranean climate: A temporal gap of diversification recovered from multiple plant phylogenies

Paleobotanical and molecular studies link diversification of plants in the Mediterranean Basin with the onset of the Mediterranean climate. Screening diversification before this period is needed in order to analyze whether the observed increase in diversification is a legitimate footprint denoting radiation or instead the biological signal of a previous mass extinction or rate stasis period. A shared post-Messinian temporal gap of cladogenesis has been previously observed in two Mediterranean sister genera. Based on this evidence we explored recently published molecular studies to recover lineages with similar diversification profiles exhibiting a cladogenesis gap. Using this criterion, we conducted a meta-analysis of 36 Mediterranean plant lineages with a post-Messinian temporal gap of cladogenesis, including a new molecular dating of Genista (Fabaceae). Whereas 39% of these lineages have not diversified since the Miocene, another 39% began to rediversify during the onset of the Mediterranean climate and the remaining 22% began diversifying again afterwards during the Quaternary. The pattern of Mediterranean diversification recovery after a temporal gap of cladogenesis was also obtained with phylogenetic tree simulations under birth and death processes when forcing one or two temporal shifts in diversification rates. The relative importance of the Mediterranean onset as a driving force promoting speciation or triggering extinction remains as an open question, since neither the mass extinction nor the rate stasis evolutionary scenarios can be rule out. The independent analysis of individual clades within phylogenies is also essential to detect clade-dependent patterns hidden by phylogeny-level ones. We disclose the importance of analyzing diversification patterns of Mediterranean lineages since the Miocene to understand the recent history of the Mediterranean biota. (C) 2013 Elsevier GmbH. All rights reserved.