Arecaceae tribe Cocoseae is the most economically important tribe of palms, including both coconut and African oil palm. It is mostly represented in the Neotropics, with one and two genera endemic to South Africa and Madagascar, respectively. Using primers for six single copy WRKY gene family loci, we amplified DNA from 96 samples representing all genera of the palm tribe Cocoseae as well as outgroup tribes Reinhardtieae and Roystoneae. We compared parsimony (MP), maximum likelihood (ML), and Bayesian (B) analysis of the supermatrix with three species‐tree estimation approaches. Subtribe Elaeidinae is sister to the Bactridinae in all analyses. Within subtribe Attaleinae, Lytocaryum, previously nested in Syagrus, is now positioned by MP and ML as sister to the former, with high support; B maintains Lytocaryum embedded within Syagrus. Both MP and ML resolve Cocos as sister to Syagrus; B positions Cocos as sister to Attalea. Bactridineae is composed of two sister clades, Bactris and Desmoncus in one, for which there is morphological support, and a second comprising Acrocomia, Astrocaryum, and Aiphanes. Two B and one ML gene tree‐species estimation approaches are incongruent with the supermatrix in a few critical intergeneric clades, but resolve the same infrageneric relationships. The biogeographic history of the Cocoseae is dominated by dispersal events. The tribe originated in the late Cretaceous in South America. Evaluated together, the supermatrix and species tree analyses presented in this paper provide the most accurate picture of the evolutionary history of the tribe to date, with more congruence than incongruence among the various methodologies.
The Caribbean Island Biodiversity Hotspot is the largest insular system of the New World and a priority for biodiversity conservation worldwide. The tribe Adelieae (Euphorbiaceae) has over 35 species endemic to this hotspot, representing a prime example of speciation in the West Indies and involving taxa from Cuba, Hispaniola, Jamaica, and the Bahamas. These species form a monophyletic group and have traditionally been accommodated in two endemic genera, Lasiocroton and Leucocroton. A study based on scanning electron microscopy of pollen, macromorphology, and molecular analysis was conducted to reveal generic relationships within this group. Phylogenies were based on nucleotide sequences of the nrITS region and the non‐coding cpDNA spacers psbM‐trnD and ycf6‐pcbM. Three major monophyletic assemblages were revealed; one of them is restricted to Hispaniola and is accommodated in a new genus, Garciadelia, with four species. The new genus is sister to a clade comprising two monophyletic groups, one including all species of Leucocroton and restricted to serpentine soils of Cuba, and a second including the species of Lasiocroton, occurring in Cuba, Hispaniola, Jamaica, and the Bahamas. Morphological, biogeographical, and ecological data provided additional support for each of these three monophyletic assemblages. Two new combinations (Lasiocroton microphyllus from Cuba, Garciadelia leprosa from Hispaniola) are made and four new species are described (Lasiocroton gutierrezii from Cuba, and Garciadelia abbottii, G. castilloae, and G. mejiae from Hispaniola).
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.
Aim Our aim was to investigate the historical biogeography of the three genera of the Leucocroton alliance (i.e. Garciadelia Jestrow & Jiménez Rodr., Lasiocroton Griseb., and Leucocroton Griseb., Euphorbiaceae). Location The alliance is restricted to the Bahamas, Cuba, Hispaniola and Jamaica. Methods Members of the Leucocroton alliance, along with representatives from tribe Adelieae (Adelia L. and Philyra Klotzsch.), were included in a molecular phylogenetic analysis based upon nucleotide sequences of the internal transcribed spacer region of the nuclear ribosomal DNA and the non‐coding chloroplast regions psbM–trnD and ycf6–pcbM. The program s‐diva was used to calculate ancestral areas based on the phylogenetic trees and present species distributions. Results Phylogenetic analyses support the monophyly of the three genera. The ancestral area of the Leucocroton alliance is eastern Cuba and Hispaniola. Ancestral forms of Leucocroton arose on eastern Cuba and underwent two migrations across the island. The ancestor of Lasiocroton also originated on eastern Cuba followed by later dispersal to and speciation events on the other islands. Our study also suggests that ancestral forms of the Leucocroton alliance probably occurred on limestone soils. Main conclusions Our study concurs with previous hypotheses suggesting that the flora of serpentinite regions of the Caribbean derives from other types of soils. The serpentine endemics of the Leucocroton alliance have a single origin and represent one of the most extraordinary examples of speciation in this unique environment of the New World. The high colonization success achieved by the members of Leucocroton on serpentine soils was not attained by the other genera of the alliance, which occur on limestone areas.
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