Topic
Rhaphithamnus
About: Rhaphithamnus is a research topic. Over the lifetime, 2 publications have been published within this topic receiving 121 citations.
Papers
TL;DR: Phylogenetic inference suggests a South American origin for Verbenaceae, with approximately six colonization events having given rise to the Old World species.
Abstract: UNLABELLED PREMISE OF THE STUDY Verbenaceae consist of trees, shrubs, lianas, and herbs distributed primarily in Latin America, where they occur in a wide array of ecosystems. A second center of diversity exists in Africa. Competing morphology-based classifications that rely on different traits conflict in significant ways. A broad phylogenetic study was undertaken to assess those classifications and to examine the historical geography of the family. • METHODS Analysis of seven chloroplast DNA regions for 109 species, representing all genera except one monotypic genus, provide inference into evolutionary relationships in Verbenaceae. • KEY RESULTS The phylogeny shows that none of the traditional classifications reflect phylogenetic relationships very well. Eight clades are recognized as tribes (Casselieae, Citharexyleae, Duranteae, Lantaneae, Neospartoneae trib. nov., Petreeae, Priveae, and Verbeneae). Two genera, Dipyrena and Rhaphithamnus, remain unplaced in these larger clades. Petreeae, which consist of Neotropical lianas, are sister to the rest of the family. Lantaneae and Verbeneae together form a derived clade that comprises approximately two-thirds of the species in Verbenaceae. • CONCLUSIONS We present a new tribal classification, including one new tribe, Neospartoneae trib. nov., to accommodate three small genera of Argentine species (Diostea, Neosparton, and Lampaya). Phylogenetic inference suggests a South American origin for Verbenaceae, with approximately six colonization events having given rise to the Old World species.
131 citations
TL;DR: Many of the characters traditionally employed in classification have proven to be very homoplastic, or have been shown not to support relationships within the Verbenaceae, and traditional assumptions concerning character polarity have in some cases been shown to be incorrect.
Abstract: Premise of the study: A new infrafamilial circumscription of the Verbenaceae with eight tribes: Casselieae, Citharexyleae, Duranteae, Lantaneae, Neospartoneae, Petreeae, Priveae, and Verbeneae, has been recently proposed, on the basis of molecular phylogenetic studies. Two genera, Dipyrena and Rhaphithamnus , remain unplaced. The aim of this work is to reconstruct the evolutionary history of morphological characters traditionally employed in the classifi cation of the Verbenaceae, with special attention to tribes Verbeneae and Lantaneae. Methods: Twenty-one characters, related to habit and vegetative morphology, infl orescence and fl oral morphology, ovary and fruit morphology, as well as chromosome number, were optimized over a molecular phylogeny of Verbenaceae. Key Results: All tribes are supported by at least one morphological trait except tribes Duranteae and Citharexyleae. Suffrutescent habit, sessile fl owers, and four cluses are synapomorphies for tribe Verbeneae. Gynoecium with short style and entire stigma are synapomorphic traits for tribe Lantaneae. Sessile fl owers and unicarpellate ovaries are morphological synapomorphies for the new tribe Neospartoneae. Suffrutescent habit is a synapomorphic trait for tribe Priveae. Homothetic pleiobotrya and absence of the adaxial staminode are synapomorphic traits for tribe Casselieae. Undivided fl eshy fruits are probably a synapomorphic trait for tribe Petreeae. Putative plesiomorphies for the ancestor of the Verbenaceae are discussed as well as synapomorphic traits within other Verbenaceae clades. Conclusions: Many of the characters traditionally employed in classifi cation have proven to be very homoplastic, or have been shown not to support relationships within the family. Moreover, traditional assumptions concerning character polarity have in some cases been shown to be incorrect.
57 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2012 | 1 |
| 2010 | 1 |