A comprehensive kelp phylogeny sheds light on the evolution of an ecosystem

Publication date: Available online 10 April 2019Source: Molecular Phylogenetics and EvolutionAuthor(s): S. Starko, M. Soto Gomez, H. Darby, K.W. Demes, H. Kawai, N. Yotsukura, S.C. Lindstrom, P.J. Keeling, S.W. Graham, P.T. MartoneAbstractReconstructing phylogenetic topologies and divergence times is essential for inferring the timing of radiations, the appearance of adaptations, and the historical biogeography of key lineages. In temperate marine ecosystems, kelps (Laminariales) drive productivity and form essential habitat but an incomplete understanding of their phylogeny has limited our ability to infer their evolutionary origins and the spatial and temporal patterns of their diversification. Here, we reconstruct the diversification of habitat-forming kelps using a global genus-level phylogeny inferred primarily from organellar genome datasets, and investigate the timing of kelp radiation. We resolve several important phylogenetic features, including relationships among the morphologically simple kelp families and the broader radiation of complex kelps, demonstrating that the initial radiation of the latter resulted from an increase in speciation rate around the Eocene-Oligocene boundary. This burst in speciation rate is consistent with a possible role of recent climatic cooling in triggering the kelp radiation and pre-dates the origin of benthic-foraging carnivores. Historical biogeographical reconstructions point to a northeast Pacific origin of complex kelps, with subs...
Source: Molecular Phylogenetics and Evolution - Category: Molecular Biology Source Type: research