Evidence of constant diversification punctuated by a mass extinction in the African cycads.

ABSTRACT: The recent evidence that extant cycads are not living fossils triggered a renewed search for a better understanding of their evolutionary history. In this study, we investigated the evolutionary diversification history of the genus Encephalartos, a monophyletic cycad endemic to Africa. We found an antisigmoidal pattern with a plateau and punctual explosive radiation. This pattern is typical of a constant radiation with mass extinction. The rate shift that we found may therefore be a result of a rapid recolonization of niches that have been emptied owing to mass extinction. Because the explosive radiation occurred during the transition Pliocene-Pleistocene, we argued that the processes might have been climatically mediated.

SUBMITTER: Yessoufou K 

PROVIDER: S-EPMC3894887 | biostudies-other | 2014 Jan

REPOSITORIES: biostudies-other