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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., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Specimens attributed to Myrcia chytraculia and associated species form a complex within M. sect. Calyptranthes, occurring sympatrically throughout the Caribbean and Central America and sharing a continuously variable suite of morphometric traits. To ascertain whether species within this complex should be treated as separate or conspecific taxa, seven morphometric traits and a further two discrete characters are analysed using univariate and multivariate statistics. Leaf size and shape are found to be indicative of subspecies, and significant mean differences of traits can be found between groups, though they overlap throughout the range of the M. chytraculia complex. As a result of these findings, updated taxonomy for this group is proposed, creating the new combinations Myrcia chytraculia var. americana, Myrcia chytraculia var. pauciflora, and M. chytraculia var. zuzygium, as well as seven new synonyms. A distribution map and a key to the new varieties are also included. [ABSTRACT FROM AUTHOR]

Myrtaceae are a large family of trees and shrubs, including ca. 2500 species within the predominantly Neotropical and taxonomically problematic tribe Myrteae. Nearly 500 species of Myrteae are endemic to the Caribbean Islands Biodiversity Hotspot, but few have been represented in phylogenetic systematic studies to date. The major goals of this survey are to identify the main lineages of Myrteae present in the Greater Antilles and potential clades for further investigation. Specific objectives are to evaluate the monophyly and placement of the following: (1) the three genera of Myrtaceae considered endemic to the Caribbean Islands (Calyptrogenia, Hottea, Mitranthes); (2) Calycolpus and Pseudanamomis sensu Bisse; and (3) Greater Antillean species of Plinia. To accomplish these aims, species of Myrtaceae representing all genera native to the Greater Antilles were sampled from across the region for placement within previously established phylogenetic frameworks for Myrteae and the large genus Eugenia. In total, 160 terminal taxa of Myrtaceae (89 Caribbean Islands endemics) were analyzed for this study. Phylogenetic inference was conducted by maximum parsimony and Bayesian methods on alignments of DNA sequence data from one nuclear (ITS) and three chloroplast (psbA‐trnH, ndhF‐rpl32, trnL‐trnF) regions. Results of both types of analysis were congruent with each other and with the major clades recovered in previous studies, but some conflict was observed between nuclear and chloroplast regions involving congeneric species. Calycorectes (= Hottea) ekmanii from eastern Cuba was found to be closely related to Calycolpus within subtribe Myrtinae. Subtribes Myrciinae, Pliniinae, Pimentinae (Pimenta and Psidium groups) and Eugeniinae contained other Greater Antillean species. Sampled species of Plinia from Cuba emerged within Myrciaria, and Mitranthes was found to be non‐monophyletic. All sampled species of Eugenia endemic to the Caribbean fell within E. sect. Excelsae (including Calycolpus sensu Bisse), E. sect. Racemosae and E. sect. Umbellatae except for E. cycloidea, which was associated with the Old World species of E. sect. Jossinia. Within Eugenia sect. Umbellatae, Caribbean species formed two major clades, designated C1 and C2, containing species of Calyptrogenia and Hottea from southern Hispaniola, a polyphyletic Pseudanamomis sensu Bisse and the Lathberry Clade, a novel group of Eugenia species centered in Puerto Rico and the Virgin Islands. Calyptrogenia and Hottea species from southern Hispaniola are transferred to Eugenia along with Pseudanamomis nipensis, while Mitranthes species are transferred to Myrcia. Two additional combinations are made within Eugenia and Pimenta in accordance with the results, and lectotypes are designated as appropriate. [ABSTRACT FROM AUTHOR]