title: Myrteae phylogeny, calibration, biogeography and diversification patterns: Increased understanding in the most species rich tribe of Myrtaceae.
abstract: Myrteae (c. 2500 species; 51 genera) is the largest tribe of Myrtaceae and an ecologically important groups of angiosperms in the Neotropics. Systematic relationships in Myrteae are complex, hindering conservation initiatives and jeopardizing evolutionary modelling. A well-supported and robust phylogenetic hypothesis was here targeted towards a comprehensive understanding of the relationships within the tribe. The resultant topology was used as a base for key evolutionary analyses such as age estimation, historical biogeography and diversification rate patterns. One nuclear (ITS) and seven chloroplast (psbA-trnH, matK, ndhF, trnl-trnF, trnQ-rps16, rpl16 and rpl32-trnL) DNA regions for 115 taxa representing 46 out of the 51 genera in the tribe were accessed and analysed using maximum likelihood and Bayesian inference tools for phylogenetic reconstruction. Dates of diversification events were estimated and contrasted using two distinct fossil sets (macro and pollen) in BEAST. The subsequent dated phylogenies were compared and analysed for biogeographical patterns using BioGeoBEARS and diversification rates using BAMM. Myrteae phylogeny presents strong statistical support for three major clades within the tribe: Australasian group, Myrtus group and Main Neotropical Lineage. Dating results from calibration using macrofossil are an average of 20 million years older and show an early Paleocene origin of Myrteae, against a mid-Eocene one from the pollen fossil calibration. Biogeographic analysis shows the origin of Myrteae in Zealandia in both calibration approaches, followed by a widespread distribution throughout the still-linked Gondwana continents and diversification of Neotropical endemic lineages by later vicariance. Best configuration shift indicates three points of acceleration in diversification rates, all of them occurring in the Main Neotropical Lineage. Based on the reconstructed topology, several new taxonomic placements were recovered, including: the relative position of Myrtus communis, the placement of the Blepharocalyx group, the absence of generic endemism in the Caribbean, and the paraphyletism of the former Pimenta group. Distinct calibration approaches affect biogeography interpretation, increasing the number of necessary long distance dispersal events in the topology with older nodes. It is hypothesised that biological intrinsic factors such as modifications of embryo type and polyploidy might have played a role in accelerating shifts of diversification rates in Neotropical lineages. Future perspectives include formal subtribal classification, standardization of fossil calibration approaches and better links between diversification shifts and trait evolution.
authors.affiliation: Comparative Plant and Fungal Biology, Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom; Department of Genetics, Evolution and Environment, University College London, WC1E 6BT London, United Kingdom. Electronic address: t.vasconcelos@kew.org.
authors.forename: Thais N C
authors.initials: TNC
authors.lastname: Vasconcelos
authors.affiliation: Departamento de Botânica, Universidade de Brasília, 70919970 Brasília, DF, Brazil.
authors.forename: Carol E B
authors.initials: CEB
authors.lastname: Proença
authors.affiliation: Faculty of Science and Natural Resources, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia.
authors.forename: Berhaman
authors.initials: B
authors.lastname: Ahmad
authors.affiliation: Herbaria, Harvard University, 021382020 Cambridge, MA, United States.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Aguilar
authors.affiliation: Centro de Diversidad de Plantas Regionales, Los Charcos de Osa, 768203, Península de Osa, Puntarenas, Costa Rica.
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Aguilar
authors.affiliation: Departamento de Botânica, Universidade Federal de Pernambuco, 50670901 Recife, PE, Brazil.
authors.forename: Bruno S
authors.initials: BS
authors.lastname: Amorim
authors.affiliation: Natural History Museum of Jamaica, Institute of Jamaica, 10-16 East Street, Kingston, Jamaica.
authors.forename: Keron
authors.initials: K
authors.lastname: Campbell
authors.affiliation: Departamento de Biologia, Universidade Federal do Ceará, 60455760 Fortaleza, CE, Brazil.
authors.forename: Itayguara R
authors.initials: IR
authors.lastname: Costa
authors.affiliation: Universidade Estadual de Goiás, 76190000 Palmeiras de Goiás, GO, Brazil.
authors.forename: Plauto S
authors.initials: PS
authors.lastname: De-Carvalho
authors.affiliation: Departamento de Engenharia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 39100000 Diamantina, MG, Brazil.
authors.forename: Jair E Q
authors.initials: JEQ
authors.lastname: Faria
authors.affiliation: Departamento de Botânica, Universidade de São Paulo, 05508900 São Paulo, SP, Brazil.
authors.forename: Augusto
authors.initials: A
authors.lastname: Giaretta
authors.affiliation: Comparative Plant and Fungal Biology, Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom.
authors.forename: Pepijn W
authors.initials: PW
authors.lastname: Kooij
authors.affiliation: Departamento de Biologia Vegetal, Universidade Estadual de Campinas, 13083979 Campinas, SP, Brazil.
authors.forename: Duane F
authors.initials: DF
authors.lastname: Lima
authors.affiliation: Departamento de Ciências Ambientais, Universidade Federal de São Carlos, 18052780 Sorocaba, SP, Brazil.
authors.forename: Fiorella F
authors.initials: FF
authors.lastname: Mazine
authors.affiliation: Departamento de Botánica, Jardín Botánico Nacional Dr. Rafael Ma. Moscoso, 10507 Santo Domingo, Dominican Republic.
authors.forename: Brigido
authors.initials: B
authors.lastname: Peguero
authors.affiliation: Comparative Plant and Fungal Biology, Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS Richmond, Surrey, United Kingdom.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Prenner
authors.affiliation: Departamento de Biologia, Universidade Federal de São Carlos, 18052780 Sorocaba, SP, Brazil.
authors.forename: Matheus F
authors.initials: MF
authors.lastname: Santos
authors.affiliation: Institut Agronomique néo-Calédonien, 98851 Nouméa, New Caledonia.
authors.forename: Julia
authors.initials: J
authors.lastname: Soewarto
authors.affiliation: School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, T12 YN60 Cork, Ireland.
authors.forename: Astrid
authors.initials: A
authors.lastname: Wingler
authors.affiliation: Comparative Plant and Fungal Biology Department, Herbarium, Royal Botanic Gardens, Kew, TW9 3AB Richmond, Surrey, United Kingdom.
authors.forename: Eve J
authors.initials: EJ
authors.lastname: Lucas
mesh_terms: D001499:Bayes Theorem; D002138:Calibration; D002736:Chloroplasts / Q000235:genetics; D019143:Evolution, Molecular; D005580:Fossils; D017343:Genes, Plant; D049810:Genetic Speciation; D014644:Genetic Variation; D058885:Multilocus Sequence Typing; D027822:Myrtaceae / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D058974:Phylogeography
keywords: Eugenia; Evolution; Myrcia; Myrtus; Psidium; Systematics