Austin R Mast1, Peter M Olde2, Robert O Makinson2, Eric Jones3, Amanda Kubes4, Eliot T Miller5, Peter H Weston2. 1. Department of Biological Science, Florida State University, Tallahassee, Florida 32306 USA amast@bio.fsu.edu. 2. Royal Botanic Gardens and Domain Trust, Mrs. Macquaries Road, Sydney, New South Wales, 2000, Australia. 3. Department of Biological Science, Florida State University, Tallahassee, Florida 32306 USA Department of Biology, University of Maine, Machias, Maine 04654 USA. 4. Department of Biological Science, Florida State University, Tallahassee, Florida 32306 USA. 5. Department of Biological Sciences and Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho 83844 USA.
Abstract
PREMISE OF THE STUDY: Subtribe Hakeinae (526 spp.) represents a large Australian plant radiation central to our understanding of that flora's evolution and ecology. It contains Grevillea-the third largest plant genus in Australia and a group inferred to have among the highest diversification rates in the angiosperms. However, we lack a robust phylogenetic framework for understanding subtribe Hakeinae and recognize that Grevillea lacks an unambiguous synapomorphy supporting its monophyly. METHODS: We used four plastid and one nuclear DNA region from a taxonomically even sampling of a third of the species to infer a time-calibrated phylogeny of Hakeinae and absolute diversification rates of major clades. We developed the R package addTaxa to add unsampled taxa to the tree for diversification rate inference. KEY RESULTS: Grevillea is paraphyletic with respect to Hakea and Finschia. Under most parameter combinations, Hakea contains the major clade with the highest diversification rate in Hakeinae, rather than Grevillea. The crown age of the Grevillea+Hakea+Finschia crown group is about double that of prior estimates. CONCLUSIONS: We demonstrate that the paraphyly of Grevillea considerably enlarges the number of Australian descendants from its most recent common ancestor but has also misled investigators who considered a single operational taxonomic unit as adequate to represent the genus for inferences of diversification rate and timing. Our time-calibrated phylogeny can form the basis of future evolutionary, comparative ecology, and biogeography studies involving this large Australian plant radiation, as well as nomenclatural changes.
PREMISE OF THE STUDY: Subtribe Hakeinae (526 spp.) represents a large Australian plant radiation central to our understanding of that flora's evolution and ecology. It contains Grevillea-the third largest plant genus in Australia and a group inferred to have among the highest diversification rates in the angiosperms. However, we lack a robust phylogenetic framework for understanding subtribe Hakeinae and recognize that Grevillea lacks an unambiguous synapomorphy supporting its monophyly. METHODS: We used four plastid and one nuclear DNA region from a taxonomically even sampling of a third of the species to infer a time-calibrated phylogeny of Hakeinae and absolute diversification rates of major clades. We developed the R package addTaxa to add unsampled taxa to the tree for diversification rate inference. KEY RESULTS: Grevillea is paraphyletic with respect to Hakea and Finschia. Under most parameter combinations, Hakea contains the major clade with the highest diversification rate in Hakeinae, rather than Grevillea. The crown age of the Grevillea+Hakea+Finschia crown group is about double that of prior estimates. CONCLUSIONS: We demonstrate that the paraphyly of Grevillea considerably enlarges the number of Australian descendants from its most recent common ancestor but has also misled investigators who considered a single operational taxonomic unit as adequate to represent the genus for inferences of diversification rate and timing. Our time-calibrated phylogeny can form the basis of future evolutionary, comparative ecology, and biogeography studies involving this large Australian plant radiation, as well as nomenclatural changes.
Authors: Eliot T Miller; Gavin M Leighton; Benjamin G Freeman; Alexander C Lees; Russell A Ligon Journal: Nat Commun Date: 2019-04-08 Impact factor: 14.919