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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]

The nomenclature of Dendrocousinsia (Hippomaneae, Euphorbiaceae) is revised and we present four new taxonomic combinations within the genus. It comprises six species and one variety. Extensive field surveys were conducted and conservation assessments are presented based on the IUCN redlist system for threatened species. Three of the species are Critically Endangered as each of them has a very restricted distribution. The other three species are Vulnerable. There has been a long debate pertinent to the taxonomic placement of Dendrocousinsia. Until extensive phylogenetic studies are performed within the Hippomaneae we propose to maintain this group as a distinct genus and not as a section within Sebastiania. This study highlights Dendrocousinsia as restricted to Jamaica with a high conservation priority because of its uniqueness and the Critically Endangered status of half of its species. [ABSTRACT FROM AUTHOR]

[Display omitted] • The eco-evolutionary history of insular Caribbean Sticta was explored. • Species assemblages date back to the early Miocene and show strong biogeographic links to South America. • Colonization of the islands did not increase diversification rates. • Environmental variation most strongly explains taxonomic and phylogenetic turnover between island-level communities. Phylogenetic approaches to macroevolution have provided unique insight into evolutionary relationships, ancestral ranges, and diversification patterns for many taxa. Similar frameworks have also been developed to assess how environmental and/or spatial variables shape species diversity and distribution patterns at different spatial/temporal scales, but studies implementing these are still scarce for many groups, including lichens. Here, we combine phylogeny-based ancestral range reconstruction and diversification analysis with community phylogenetics to reconstruct evolutionary origins and assess patterns of taxonomic and phylogenetic relatedness between island communities of the lichenized fungal genus Sticta in the Caribbean. Sampling was carried out in the Greater Antilles (Cuba, Jamaica, Dominican Republic, and Puerto Rico) and Lesser Antilles (Dominica, Guadeloupe, and Martinique). Data for six molecular loci were obtained for 64 candidate Caribbean species and used to perform both macroevolutionary phylogenetics, which also included worldwide taxa, and phylobetadiversity analyses, which emphasized island-level communities. Our work uncovered high levels of island endemism (∼59%) in Caribbean Sticta. We estimate initial colonization of the region occurred about 19 Mya from a South American ancestor. Reverse migration events by Caribbean lineages to South America were also inferred. We found no evidence for increased diversification rates associated with range expansion into the Caribbean. Taxonomic and phylogenetic turnover between island-level communities was most strongly correlated with environmental variation rather than with geographic distance. We observed less dissimilarity among communities from the Dominican Republic and Jamaica than between these islands and the Lesser Antilles/Puerto Rico. High levels of hidden diversity and endemism in Caribbean Sticta reaffirm that islands are crucial for the maintenance of global biodiversity of lichenized fungi. Altogether, our findings suggest that strong evolutionary links exist between Caribbean and South American biotas but at regional scales, species assemblages exhibit complex taxonomic and phylogenetic relationships that are determined by local environments and shared evolutionary histories. [ABSTRACT FROM AUTHOR]

Premise of research. Biogeography has improved understanding of evolution and diversification of organisms on both continental and island systems. One complicated island group in terms of geological history and biogeographic pattern is the Caribbean island system. A comparison across taxonomic groups does not result in overarching patterns for this group of islands. Columnea has the greatest number of species endemic to the Caribbean for any genus in Gesneriaceae that is not mostly endemic to the Caribbean with 16 species. Thirteen of these species are found on Jamaica, the remaining three each endemic to Cuba, Hispaniola, and Puerto Rico. In addition, populations of Columnea sanguinea and Columnea scandens are known from both mainland and multiple Caribbean islands. We investigate the pattern of evolution in Caribbean species of Columnea and attempt to explain the large number of species found on the island of Jamaica relative to the other islands. We explicitly test whether Caribbean species of Columnea are monophyletic and whether the 13 species endemic to Jamaica are a monophyletic group. This genus can help understand biogeographic patterns and modes of speciation in the Caribbean. Methodology. We sampled all Caribbean species of Columnea using DNA sequence data and phylogenetic methods to understand the pattern of diversity to determine whether multiple or single introductions could explain the diversity on the Caribbean islands. Pivotal results. The Caribbean species do not form a monophyletic group. The Jamaican species are monophyletic, and the endemic Cuban species, Columnea tincta , is sister to 12 of the Jamaican species, with Columnea pubescens sister to C. tincta + remaining Jamaican species. Most Jamaican species share similar corolla morphologies to section Columnea. Although never recovered as part of section Columnea , approximately unbiased tests cannot reject a sister group relationship of the Jamaican/Cuban endemic clade to section Columnea but can reject inclusion in section Columnea. Conclusions. The high diversity of Columnea in the Caribbean is due to the disproportionate number of species on Jamaica, but there is no obvious explanation for the radiation on this island, despite considering island size, topography, pollinators, and dispersers. The large number of species could be attributed to over-splitting on Jamaica, but even if a narrower concept were followed, and four of the species were combined as varieties of Columnea hirsuta as earlier taxonomy had predicted, the number of morphologically distinctive species would still be nine and much greater than that of the other islands. Our data also indicate that C. hirsuta sensu lato is not monophyletic. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Portlandia(Rubiaceae) is a genus endemic to Jamaica. The volatile organic constituents ofP. albiflora,P. coccinea,P. grandiflora,P. latifoliaandP. proctoriiwere analyzed by headspace solid-phase microextraction (SPME) coupled with capillary mass spectrometry. The main constituents detected in these species are 1-penten-3-one, hexanal, (E)-2-hexenal, linalool, borneol and methyl salicylate. All species are rich in aliphatic aldehydes, mainly represented by (E)-2-hexenal, that range from 17% (P. latifolia) to 90% (P. coccinea) of total volatiles. The high content of aldehydes is characteristic toPortlandiaspecies and may serve as a chemical marker to differentiatePortlandiafrom related genera within the Rubiaceae. [ABSTRACT FROM PUBLISHER]

The article provides information on the noteworthy collections of Heterotis rotundifolia at the Portland Parish in Jamaica and at the Saint David Parish in Dominica. It says that the Jamaican collection represents the first documented naturalized occurrence in the country of the commonly cultivated herbaceous melastome. The author adds that the other collection represents the first documented naturalized occurrence of the species in Dominica. The qualities of H. rotundifolia are also discussed.